a)IMASS SA,GREECE

b) YOKOHAMA,JAPAN  www.yrc.co.jp

c) TAERUYK RUBBER ,S.KOREA  www.taeryuk.en.ec21.com

d) PHOENIX YULE  www.phoenix-conveyorbelts.com

2.IDLERS

a) KALI,KUMBAKO NAM

b) V V N MFG  VV NAGAR

c) ELECON, VV NAGAR

                        This specification is intended to cover the following activities and services in respect of all the equipments of Coal Handling Plant for 2×500 MW units.

1.1.0                 Scheme of Coal Handling System

1.1.1                 Coal shall be transported to the plant in bottom discharge wagon rakes and shall be unloaded in under ground R.C.C. Track hopper.

1.1.2                 Six (6) number paddle (Rotary plough) feeders, each of 800 T/Hr rated capacity shall be installed at the bottom of the Track hopper to scoop the coal from track hopper and feed coal on to the underground conveyors 1A/1B. There shall be three paddle feeders on each conveyor of which two shall work simultaneously and one shall remain stand by.

1.1.3                 Two (2) nos. In-Line Magnetic separators to remove tramp iron pieces shall be mounted on the discharge end of conveyors 3A/3B. The rated capacity of each conveyor in coal handling plant shall be1600 TPH.

1.1.4                 Conveyor 1A/1B will discharge coal on conveyor 2A/2B in transfer point TP-1.  Conveyor 2A/2B will carry coal to Primary Crusher House for crushing coal from 300mm to (-) 150mm. In the Primary crusher House each of the conveyor 2A and 2B shall transfer coal to separate sets of two Crushers through feeders, such that coal flow may be properly distributed to the crushers in service. There shall be Four (4) numbers rotary breakers each of 800 TPH capacity with two (2) normally working and two as standby. Provision shall be made such that all the four crushers may run when both streams are required to operate.

1.1.5                 Two (2) nos. belt weigh scales shall be provided on conv. 1A/1B for weighing the coal received in the track hopper.

1.1.6                 Conveyor 3A/3B will convey coal to Secondary Crusher house which shall have four (4) Crushers each of 800 TPH capacity. Coal from each incoming conveyor 3A/3B to crushers will pass through a set of two nos. dedicated vibrating roller screens so that maintenance of equipment, hopper, chutes in either stream does not affect the operation of other stream.

1.1.7                 Each roller screen shall be of 800 TPH capacity. The four (4) Crushers, each of 800 MTPH capacity, shall crush the coal to (-) 20 mm size. Input coal above 20 mm size shall be fed to the crushers. Both, the screened coal below 20 mm size and crushed coal shall be discharged either onto conveyor 4A/4B or to  or or to stacking yard Conveyor No. 8. From conveyor 4A/4B, normally the crushed coal will be fed on Conveyor 5A/5B for onward transmission to Conveyor 6A/6B through the transfer point2 (TP-2), TP-3 and TP-4.  In TP-2 and TP-3, provision shall be kept for feeding the coal to one future conveyor for second future Stacker-cum-Reclaimer and Conveyor for extension stage if required.

1.1.8                 Stacker-cum-Reclaimer is envisaged for stock-yard having reversible conveyor 8 as yard conveyor. The feeding of coal from conv. 8 on boom conveyor of SR shall take place during stacking mode. Yard conv. 8 shall discharge coal on conv. 9A/9B at TP-6 while on reclaim mode.

1.1.9                 At TP-5, conveyor 6A/6B will discharge coal onto conveyor 7A/7B. Two (2) nos. In-line magnetic separators (ILMS) shall be provided over the discharge end of conveyor 6A/6B for extraction of tramp magnetic pieces.

1.1.10               Two (2) nos. belt scales shall be provided on conveyor 6A/6B for weighing the coal received from stock yard.

1.1.11               Conveyor 6A/6B shall discharge coal onto bunker bay conveyors 7A/7B at TP-5.

1.1.12               One (1) no. Travelling Tripper mounted on each of the conveyors 7A/7B shall feed coal into Raw coal bunkers of the boiler units.

1.1.13               One (1) no.  stacker cum reclaimer (S/R) machine of 1600 TPH rated capacity shall be provided on yard conveyor 8. The S/R machine shall operate on rails for stacking/reclaiming the coal in the stock yard area. During reclaiming the coal shall be conveyed to the yard conveyor 8 by reclaiming operation of S/R machine and shall be fed to conveyor 9A/9B at TP-6. During stacking mode of operation of the machine, coal from crusher house shall be fed to yard conveyor 8. One belt scale shall be provided on Yard Conveyor.

1.1.14               Two nos. coal sampling units  shall be installed one each at crusher house and TP-4 to sample the coal of (-) 150 mm size and (-) 20 mm size respectively.

1.1.15               In the event of direct flow through 1A/!B, 2A/2B, 3A/3B, 4A/4B is not resorted, then the coal will be reclaimed from coal heap with the help of S/R and chain of conveyor No. 8, 9A/9B and 10A/10B and will be transfer crushed coal to conveyor 6A/6B at TP-4

1.1.16               In the case of S/R being out of order and crushed coal is required to be reclaimed, six emergency underground reclamation hoppers shall be provided on conveyor No. 9A/9B. The coal from crushed coal heaps shall be dozed into these hoppers with the help of Bull-Dozer.

1.3.0 System Design Basis

1.4.0 Spare Parts

1.6.0 Equipment Specification

1.8.0 Testing and Inspection

VENDERS

Manapakam, Post Bag No. 979,

Chennai – 600 089.

5.Tecpro Systems Ltd 

www.tecprosystems.com

106, Vishwadeep Tower,
Plot No.4, District Centre,
Janakpuri, New Delhi-110 058
Ph: +91 11 4503 8735
Fax:+91 11 4503 8734

6. M/s Mc Nally Baharat
7th Floor 4 Mangoe Lane
Kolkata

www.mcnallybharat.com

7. M/s MBE Lignite Handling
7th Floor 4 Mangoe Lane
Kolkata

8.Energo Engineering Projects Ltd

Add: A-57/4, Okhla Industrial Area, Phase-II,

New Delhi 110020
Tel: 011-26385323/28/29/38
Fax: 011-26385333
E mail: energo@energoindia.com
www.energoindia.com

===========================

 www.specahp.wordpress.com

www.specmillreject.wordpress.com

www.specinstrumentation.wordpress.com

The work shall include but not limited to the following:

1.2.1                 Mechanical Equipment

1.2.1.1              Six (6) Nos. Paddle feeders, complete with all electricals, rails, supporting structures, end stops, cable reeling drums, trailing cables and necessary accessories.

1.2.1.2              Complete Belt Conveying Systems including Conveyor Nos. 1A/1B, 2A/2B, 3A/3B, 4A/4B, 5A/5B, 6A/6B, 7A/7B, 8, 9A/9B and 10A/10B complete with conveyor supporting structures, short supports, stringers, deck plate, seal plate etc. drive motors, drive units, pulleys, idlers, gravity take ups, take up structure upto ground level, internal and external belt wipers, pull chord switches, belt sway and zero speed switches, electro-hydraulic thruster brakes, all electricals etc. including all civil, structural and architectural works for conveyor gallery, gallery supporting trestles and their associated foundations.

1.2.1.3              Tripper floor belt conveyors 7A/7B in the bunker building complete with conveyor supporting structures, short supports, stringers, deck plate, seal plate etc. drive motors, drive units, pulleys, idlers, gravity take ups with guides upto ground level excluding the take-up structure, internal and external belt wipers, pullchord switches, belt sway and zero speed switches, electro-hydraulic thruster brakes etc. and all electricals etc.

1.2.1.4              Yard conveyor 8 complete with conveyor supporting structures, short supports, stringers, deck plates, etc., drive motors, drive units, pulleys, idlers, take-ups, take-up structure, internal and external belt wipers, pull – chord switches, belt sway and zero speed switches, electro hydraulic thruster brakes, all electricals, etc. including all civil, structural and architectural works and their associated foundations.

1.2.1.5              Four (4) Nos. Vibrating feeders in Primary Crusher House complete with drives, all mechanical, electrical and accessories. Four Nos. Rotary Breakers complete with drives, all mechanical, electrical including civil and structural works.

1.2.1.6              Two (2) numbers crusher house (one primary crusher house and one secondary crusher house) complete with all civil, structural, architectural and electrical works etc accommodating four nos. crushers and associated vibrating grizzly feeders, gates etc., goods cum passenger lift, conveyors, chute work alongwith actuator operated flap gates, hoists and other equipment such as coal sampling unit, dust suppression & ventilation system etc. as specified elsewhere.

1.2.1.7              Four (4) nos. roller Screens (in secondary crusher house) complete with drives, all mechanical, electricals and accessories.

1.2.1.8              Four (4) nos. crushers complete with drives, all mechanical, electricals including civil & structural works, vibration isolation system with springs & viscous dampers, vibration monitoring system etc.

1.2.1.9              Four (4) sets of Gates each comprising of one rod gate and one actuator operated rack & pinion gate at inlet to each of the above vibrating roller screens complete with drives, all mechanical, electrical,  structural works etc.

1.2.1.10            Transfer point TP1 alongwith under ground tunnel and pent  house PH-I, TP-6 alongwith underground tunnel and pent house PH’ and drive house for yard conveyor 8 complete with all civil, structural, architectural and   electrical works including  chutes,  monorails, hoists/chain pulley  blocks, hoist maintenance platforms,  RCC/steel floors, external staircases, hand rails etc.  All transfer points shall have separate debris disposal chute right up to the ground floor.

1.2.1.11            All mechanical, electrical equipment to be housed in Transfer points TP-1, TP-2, TP-3, TP-4, T.P-5, T.P-6, T.P-7,  drive house of yard conveyor and pent houses including chutes, maintenance / operating platforms, Monorails, electric hoists etc.

1.2.1.12            One (1) no. stacker cum reclaimer machine having rated capacity of 1600 TPH/ 1600 TPH complete with all equipment and conveyors, structural, electricals, cable reeling drums, all trailing cables and accessories, rails, rail foundations, fixing and grouting of rails  and other associated civil & structural works to operate in conjunction with yard conveyor 8.

1.2.1.13            Complete chute work along with chute block switches and actuator operated flap gates between various conveyors and equipment at all transfer points and crusher house.

1.2.1.14            Three (3) Nos. passenger – cum – goods elevators with drives, all mechanical, civil, structural & associated foundation works, accessories and electricals to serve various floors of the Primary and secondary Crusher House (CH) and TP-5

1.2.1.15            Two (2) Nos. motorized Travelling Trippers, One (1) each on conveyor 7A/7B. Trippers shall be complete with all mechanical, electrical equipment, rails, rail supporting structure (any structural stools, if required), cables with cable reeling drum, all trailing cables, brakes, rail clamp etc.  Grid/ grating over the bunker slot on tripper floor is to be provided by the bidder.

                        The drive chain equipment for conveyor 7A/7B therefore shall first be placed at the end of unit no. 1 bunkers for commissioning of unit no. 1 and shall be later shifted at the end of the bunker bay at the time of commissioning of unit no. 2.  Bidder’s scope of work shall include shifting of the drive chain equipment for conveyors 7A/7B for unit no.2 commissioning including its associated civil and electrical works and making good the bunker floor after shifting of the drive chain equipment to its ultimate location for unit no. 2 commissioning.

1.2.1.16       Adequate number of ventilation for ventilating the track hopper, TP-1, underground portion of conveyor 1A/1B, under ground portion of TP-6 and under ground portion of conv. 9A/9B and bunker bay (housing tripper conveyors) complete with all mechanical, electrical, civil and structural works.

1.2.1.17            Pressurised Ventilation system for all HT Switchgear room, MCC rooms and S&T room complete with all mechanical, electricals, accessories, civil and structural works.

1.2.1.18            Air conditioning of Main CHP control room; operator’s cabin & MCC room on Stacker/Reclaimer complete with all electricals, civil & structural works etc.

1.2.1.19            Minimum nine (9) Nos. sump pumps six (6) nos. in track hopper and three (3) nos. sump pumps each in underground tunnel and Transfer point of Conveyor no. 9A/9B complete with motors, local control panel, level switches, individual discharge piping with fittings and valves to nearest plant drain as specified and as indicated elsewhere.

1.2.1.20            Two (2) Nos. coal sampling units, one for (-) 300 mm size coal complete with all accessories and electricals, supporting structures, approach/ maintenance platforms in unit, in crusher house and one for (-) 20 mm size coal in TP-4 complete with all accessories and electricals, supporting structures, approach/ maintenance platforms.

1.2.1.21            One (1) No. belt vulcanising machines of adequate size complete with all mechanical, electricals, accessories and consumables.

1.2.1.22            Four (4) Nos. Inline Magnetic Separators, complete with reject chutes, reject bins, and all mechanical, supporting arrangement, electricals, civil, structural works and accessories.

1.2.1.23            Four (4) Nos. Electronic Belt weighers complete with all mechanical, supporting arrangement, electricals, and accessories.

1.2.1.24            Complete dust suppression system for control of fugitive dust in track hopper, paddle feeder, transfer points, crusher house, coal stock yard complete with pump houses, water tanks, pumps, drives, piping, valves etc.

1.2.1.25            Belt Sealing arrangement in Bunker bays to operate in conjunction with tripper for control of dust coming out of R.C. Bunkers.

1.2.1.26            Suitable monorails and electrically operated hoist blocks as well as hand operated chain pulley blocks for servicing/ installation / easy replacement of drive machinery, different types of pulleys for all conveyors, GTU and other equipment from ground level to all locations. Electric hoist provided at bunker (Tripper) floor and all transfer houses/crusher house shall also be able to lift  one belt drum (including wooden/ Steel drum) safely.

1.2.2                 Electricals

Two nos. 11 kV feeders and two nos. 3.3 kV supply feeders shall be provided from 11 kV & 3.3 kV station board for feeding entire CHP.

The scope of work shall include, but not limited to the following:

1.2.2.1              3.3 KV CHP Switchgears to feed HT drives including Stacker Reclaimer and auxiliary transformers.

1.2.2.2              Auxiliary Transformers :

a)                Two (2) nos. 11/3.45 kV, ONAN, out door transformers for 3.3 KV CHP Switchgear.

b)               3.3 / 0.433 KV, ONAN, out door transformers for each of the CHP MCC-I, II, III.

c)                One (1) no. 3.3/0.433 KV, Dry type indoor Transformer for S/R machine

1.2.2.3              Three (3) nos. of 415 V CHP MCCs to feed LT loads of entire coal handling plant. These three CHP MCCs are proposed to be located as follows :

a)         MCC-II in the MCC room near Track hopper area.

b)         MCC-I in the switchgear room at CHP control room building near             Secondary Crusher House.

c)         MCC-III in the MCC room near Transfer Tower.

1.2.2.4              One (1) no. of 415 V Stacker/Reclaimer MCC.

1.2.2.5              3.3 KV segregated phase bus ducts from 11/3.45 KV transformer to 3.3 KV CHP switchgear alongwith bends, terminations, supports etc.

1.2.2.6              Control desk and Programmable logic controllers (PLCs) :

a)                Main control desk with CRT/keyboard and large video screen, PLC panels, remote I/O racks etc. for the control of the entire coal handling plant.

b)               PLC system with control desk and I/O racks etc. for Stacker/ Reclaimer machine.

1.2.2.7              AC distribution boards as required.

1.2.2.8              Six (6) nos. DC distribution boards (2 Nos. each at the location of MCC-I, II, III.

1.2.2.9              Local push button stations for all drives.

1.2.2.10            Internal and external illumination system for the complete CHP & coal stock yard, including track hoppers, TPs/ conveyors in bunker area etc.

1.2.2.11            3.3 KV and 1.1 KV grade FRLS, XLPE/ PVC, AI/Cu, Armoured power, control, trailing and special cables for the complete system

a)         between equipment supplied under this specification.

b)         between equipment supplied under this specification and   Purchaser’s equipments.

1.2.2.12            Cable trenches / trestles including trays and supporting arrangement etc., required for the cables including laying & termination / jointing etc.

1.2.2.13                        Earthing and lightning protection system for all equipment and buildings.

1.2.2.14                        Close circuit TV system.

1.2.2.15                        Grouting of bolt holes and underside of base plates.

1.2.2.16            One (1) No. Main CHP control building located adjacent to the secondary Crusher House to house Main Control Desk, PLC panels for the coal handling plant on the first floor and 3.3 KV CHP switchgear, 415V CHP MCCs  DCDB, lighting panels etc. on the ground floor.  Associated auxiliary outdoor transformers shall be located suitably adjacent to the building.

1.2.2.17            Two (2) no. MCC rooms each  to be located near T.P-1 and T.P-5. Each MCC room shall have 415V CHP MCC-1 and CHP-MCC-II respectively, lighting distribution boards, DCDB, I/O panel etc. Associated auxiliary outdoor transformers shall be located suitably adjacent to the building.

1.2.2.18            One (1) no. S&T (signalling & telecommunication) building to be located at exit of  track hopper.

1.2.2.19            All MCC room buildings shall be complete with all electrical, civil, structural, architectural works, cable trenches, fire safety walls, foundation / fencing / earthing for transformers etc.

1.2.2.20                        All cable/duct tanks/trenches/trestles including civil & structural works.

1.2.3.0              Control & Instrumentation

                        Operation and Control Philosophy

                        The coal handling system shall be controlled from the following control points.

1.2.3.1              Coal Handling Plant Main Control Room

Overall, operation of the following equipment of Coal Handling Plant shall be controlled from the main CHP control room.

a)         Conveyors, feeders, flap gates, R & P gates, crushers, Vibrating Roller Screens.

            b)         Paddle feeders (running status with stop facilities).

            c)         Complete Dust Suppression system & service water system.

            d)         Ventilation system (group/individual control as required).

            e)         Vibration Monitoring System

            f)          In line Magnetic separators (ON/OFF control with indication).

            g)         Coal Sampling Systems (ON/OFF control with indication).

            h)         Belt weigher (ON/OFF control with indication)

            i)          Stacker Reclaimer (ON/OFF status with stop facilities).

            j)          Mobile trippers over bunkers (tripper position indications).

1.2.3.2              Local Control Panels

            Local control stations for following equipment’s shall be provided

            a)         Paddle feeders along with its dust suppression system

            b)         Mobile trippers over bunkers

            c)         Coal Sampling units

            d)         Belt Weighers

            e)         Electric hoist – wall mounted control box with pendent push button                                    controls.

f)                In line magnetic separators

g)                Sump Pump

h)               Suspended Magnet

All the above local control panels shall be accessible and located near their respective equipment and shall be complete with all the required controls, interlocks, annunciation’s etc. Further, necessary controls, indications and annunciation’s for all the above equipment shall also be provided at main CHP Control Room as described under relevant clause.

1.2.3.3              Stacker / Reclaimer Control Room

The entire control & operation of Stacker Reclaimer machine shall be from the operator’s cabin on the machine itself.

1.2.3.4              In addition to the remote control of various equipment’s, local stop push button stations shall be provided for all equipment.

Track hopper to the reclaim conveyor shall be controlled from the paddle feeder itself based on instructions from main control room. 

1)         The following equipment will not come under interlock of the        conveyor scheme.

            2)         Belt sway switch – not operated

3)               Under speed switch – closed at 90% speed of the conveyor within designed accelerating time.

            4)         Motor protection – not tripped

            5)         Local stop PB – reset

6)         Chute Block switch – not operated.  Two such switches shall be provided.

            7)         End of travel limit switches – reset.

1.2.3.5              Annunciation System:

The mimic panel cum Control desk shall be provided with adequate number of facia type annunciation windows operating through PLC for audio-visual fault annunciation purposes. Wherever group annunciation is provided, alarm status of individual equipment shall be provided on CRT.

The mechanical and structural / civil system shall be designed for 1600 TPH rated capacity and round the clock operation with both the streams operating simultaneously.

i)          The Coal delivered to the power station shall be of size 300 mm & below.             Occasionally 1-2% coal of 400 mm lump size may also be encountered.

ii)                HGI of the Coal shall be between 44 to 65. Normally moisture content in coal will vary between 12% to 15%. However for design purposes, moisture content of 20% shall be considered.

iii)              Due to open cast method of mining involved, the coal may contain shale and sand stone as high as 20%. Also occasionally metal pieces  like broken shovel teeth, brake shoe, wires etc., may also come alongwith coal from open cast mine.

iv)              The coal “as received” shall contain varying percentage of fines. Coal with such fines may tend to form adhesive lumps, particularly during monsoon when surface moisture is at its maximum value.

The sizing and selection of the vital equipment viz. crushers, vibrating roller screens, paddle feeders etc. covered under the system shall be based on the above characteristic of coal and operating conditions. Bidder shall ensure that equipment/ system efficiency shall not be effected particularly during monsoon when surface moisture is at its maximum value.

For the purpose of volumetric computation, the bulk density of the coal shall be taken as 800 kg/m3. Therefore for calculation of belt conveyor capacity, for their drives & drive motors kW requirement, and sizing (volume calculations) of chute, hoppers etc. the above bulk density shall be considered. For all other purpose viz. for stresses/ load on structures, torque calculations of paddle wheel of paddle feeder, bucket wheel of stacker / Reclaimer, sizing of actuators for flap gates, R&P gates, calculations of plugged chute/ hopper loads etc. the bulk density of the coal shall be taken as 1100 kg/m3.

All mechanical, and structural / civil system design shall consider simultaneous running of both the streams, starting of one stream with the other stream in standstill condition as well as starting of one stream with the other stream in operation.

1.3.1                 System Requirement

The CHP facility shall have two (2) coal streams; one (1) operating + one (1) standby having guarantee capacity of each stream as 1600 TPH.

CHP shall be operated normally for two shifts per day (single stream operation basis) to meet the daily coal requirement of the two (2) units.   However, all components of CHP facility shall be designed for continuous duty of 24 hours/day.

The CHP shall be designed & installed such that any one stream can be operated and if required both the streams can be operated simultaneously.

1.4.1                 General

The Contractor shall indicate and include in his scope of supply all the necessary mandatory spares, start-up commissioning spares and recommended spares in the relevant schedules. The variation in quantity of spares based on unit rates (rates as quoted for mandatory spares and rates as mutually agreed for recommended spares), if desired by the Purchaser shall be acceptable to the contractor.

The Purchaser reserves the right to buy any or all mandatory and recommended spares. The contractor shall identify service expectancy period for all items of spares, under normal operating conditions before order placement.

The Contractor shall also indicate the unit wise population of each item and the service expectancy period for the spare parts (both mandatory and recommended) under normal operating conditions before order placement is necessary.

All spares supplied under this contract shall be strictly interchangeable with the parts for which they are intended for replacements. The spares shall be treated and packed for long storage under the climatic conditions prevailing at the site, e.g. small items shall be packed in sealed transparent plastic bags with dissector packs as necessary.

Each spare part shall be clearly marked or labeled on the outside of the packing with the description. When more than one spare part is packed in single case, a general description of contents shall be on the outside of such case and a detailed list enclosed. All cases, containers and other packages must be suitably marked and numbered for the purposes of identification.

Purchase specification & addresses of Procurement sources of all mandatory spares & recommended spares shall be furnished. Details of all types of bearings in the plant shall also be furnished.

1.4.1                 Mandatory Spare Parts

The list of mandatory spares, which are considered essential by the Purchaser, is indicated in enclosed Annexure-  . The Purchaser reserves the right to buy any or all mandatory spares. The Bidder shall include all the mandatory spares in his proposal. The Bidder shall furnish in the relevant schedule of Bid proposal sheets, the itemwise and total price for these spares mentioned in the above Annexure. Further whenever the spares are indicated in percentage and numerical figures, arrived is in fraction, the same be converted to the next whole number.

In line with the requirements in ITB, the prices for mandatory spares indicated separately shall be used for bid evaluation purposes. All mandatory spares shall be delivered at site at least two months before scheduled date of trial operation of the system. However, spares shall not be dispatched before dispatch of corresponding main equipment.

1.4.2                 Recommended Spares

In addition to the spares mentioned above, the contractor shall also provide a list of recommended spares with unit and total prices for 3 years of normal operation of the system for spares of Indian origin and 5-years for spares for non-Indian origin in relevant schedule of Bid Proposal Sheets. The list shall take into consideration the mandatory spares specified in Annexure-     and should be independent of the list of the mandatory spares. The Purchaser reserves the right to buy any or all recommended spares.

Prices of recommended spares will not be used for the evaluation of Bids. The prices of these spares will remain valid upto 12 months after the placement of order for  main equipment package. The Purchaser reserves the right to buy any or all recommended spares. Further, the prices of recommended spares wherever common with the mandatory spares shall be the same as those of mandatory spares. Prices of recommended spares not listed as mandatory spares shall be reviewed by Purchaser and shall be mutually agreed with the contractor. However, the contractor shall be liable to provide necessary justification for the quoted prices for the spares desired by the Purchaser.

1.4.3                 Start-up Commissioning Spares

Start-up commissioning spares are those spares which may be required during the start-up and commissioning of the equipment / system. All spares used until the plant is handed over to the Purchaser shall come under this category. The contractor shall provide for an adequate stock of such start-up commissioning spares to be brought by him to the site for plant erection and commissioning. They must be available at site before the equipment are energised and the unused spares, if any, should be removed from there only after the issue of taking over certificate. All start up spares, which remain unused at that time, shall remain the property of the Contractor. The list of commissioning spares to be brought by the Contractor to ensure smooth commissioning of the plant shall be subject to Purchaser’s approval. The Contractor shall submit a complete list of all such start-up commissioning spares. The cost of above spares, if any, and that consumed before the handing over of the plant shall be deemed to have been included in the lumpsum proposal price of the package and the Contractor shall have no claim on this account to the Purchaser.

All cases, containers, other packages are liable to be opened for such examination, as may be considered necessary by the Project manager.

In case contractor is not able to submit report of type test(s) conducted in last five years, or in case type test report(s) are not found to be meeting the specification/relevant standard requirements, then all such tests shall be conducted under this contract by the Contractor free of cost to Purchaser, and reports shall be submitted for approval.

Even if the Bidder is furnishing valid test report as indicated above, Purchaser may get some type test conducted under this contract as specified in subsequent chapters for which Bidder shall include in his total equipment price the cost of carrying out all such type tests. The charges for each of these type tests shall be given separately in the relevant schedule of bidding documents for the price adjustment purpose, in case waiver of any test at a later date.

All acceptance and routine tests as per relevant standard and specification shall be carried out. Charges for these shall be deemed to be included in the bid price.

                        Tests at Site

After erection at site, the complete system/ equipment will be operated at site to show satisfactory performance as required by the applicable clauses of the specification. Further, all piping shall be hydraulic-tested at site.

The contractor shall furnish the quality procedures to be adopted for assuring quality from the receipt of material at site, during storage, erection, pre-commissioning to final trial run and commissioning of the complete system/ equipment.

1.6.1                 Paddle Feeder

Travelling paddle feeders of self-contained, self-propelled design shall be furnished and erected to scoop out coal from the hopper and each feeder shall be capable of travelling back and forth along the entire length of the hopper and transfer the coal from the hopper uniformly onto the conveyors below. Each paddle feeder shall have capacity to scoop out coal at the guaranteed capacity in both forward and reverse motions with no indication of wheel slipping (water tank full). Each paddle feeder shall be designed for guaranteed capacity while handling entire range of lump sizes.

It shall operate on the principle of positive discharge and shall not depend on friction or moisture content.

The Paddle wheel shall be driven by a stepless hydraulic drive. Carriage travel shall be achieved through electric motor gearbox (2 speed) and flexible coupling or through hydraulic drive. Minimum number of starts/min. for chain drive equipments shall be 15 starts/min. (with minimum 10 consecutive starts)

All equipment’s shall be designed to withstand any rate of acceleration imparted by drives or any strain resulting from a sudden change in load. Further, the design of paddle feeder carriage should be such that it does not run off from its rails due to sudden change in load or other reasons.

The Bidder shall include in his proposal necessary electricals for paddle feeder and carriage such as motorised cable reeling drum with trailing cables, cable trays for resting the trailing cables, and end limit switches for protection against over travel of the feeder carriage. The cable reeling drum and trailing cable of each feeder shall be suitable for the entire length of the hopper. Mechanical track stops shall also be provided. Dust suppression equipment for paddle feeder shall also be provided.

For designing the paddle wheel as well as travel drive, Bidder shall consider the hopper fully loaded with coal on either side of the paddle wheel to the maximum capacity.  The hydraulic system normal average working pressure shall be selected considering the above loading condition. Further hydraulic system shall be designed to stall / trip beyond a certain pressure above the normal average working pressure. The minimum margin between the normal working pressure and the stall / trip pressure shall be 50%.

Feeder carriage drive shall be suitably designed so that the forward & reverse movement of carriage can be achieved without stopping the scooping operation. Tank filled with water in DS trolley shall also be considered for travel drive.

Rail having section of 90 lb/yard structure shall be designed considering two-wheel support and accounting no frictional force from the other two wheels and considering hydraulic motor stall condition.

The hydraulic motor shall be selected based on 110% of actual power requirement motor output shaft at specified guaranteed capacity. The capacity of paddle adjustment shall be 0 to 100% of the guaranteed value.

Bidder’s design of paddle feeder should not incorporate a separate loading table (impact cradle) below the paddle feeders. However, the height of fall of coal between paddle wheel and conveyor belt shall be kept minimum. Further, the length of the skirt board shall adequately extended on both sides of the paddle wheel so that there is no spillage of coal on to the paddle feeders trolley. Minimum 500 mm extension shall be considered for this purpose. Hydraulic components shall be provided with dust proof cover for protection against spillage of coal/ dust. 

Complete telephone communication system shall be provided between each paddle feeder and main CHP control room.

The paddle feeders shall run on rails mounted on the supporting structures of associated conveyors. Both paddle feeder and carriage drives shall be mounted on the feeder carriage.

The paddle feeder wheel shall comprise of suitable numbers of vanes with cutting edges. The vanes shall be of high strength steel construction with removable tiscral or equivalent liner plates. Vanes shall be easily removable individually.

The feeder carriage shall be of steel construction and of robust design. Skirt plates shall be provided integral with the equipment for collecting the material drawn by the paddle feeder from the track hopper and discharging on to the conveyor belt. Feeder skirts of paddle feeders shall be extended at least by 500 mm on either side of the paddle wheel to avoid spillage of coal. Necessary baffle/retainer plates for suitably guiding the flow of coal from track hopper to the reclaim conveyor being fed by paddle feeders shall be provided. Hand railing shall be provided on the top deck of feeder carriage together with an access ladder.

The feeder carriage shall be provided with suitable number of double flange wheels of steel construction, complete with sealed bearing unit. The drive mechanism shall be suitable for continuous reversible motion of the carriage. Start/stop switches shall be provided at the local control panel for the operation of paddle wheel and feeder carriage. The carriage shall automatically reverse its motion, when two paddle feeders operating on the same track come within a predetermined distance. Suitable anti-collision device (infrared and mechanically operated limit switch type) shall be provided.  Provision shall be made to trip the track hopper conveyor from respective paddle feeder and provision shall be made for tripping of paddle feeder from CHP main control room.

Suitable indication of paddle wheel rpm shall be provided on the paddle feeder control panel and flow rate indicator of belt weigh scale shall also be duplicated on control panel of paddle feeder.

Suitable rail cleaners shall be provided at the leading as well as trailing side of the feeder carriage for both tracks.

Suitable cable trays minimum 300 mm above floor shall be provided along the travel of paddle feeder for supporting and guiding the trailing cables. In order to save flexible cables from damage due to tension/over-tension protection switches shall be provided.

Spacing of carrying idlers in the loading zone of paddle feeders shall be 600mm. Various equipment of Paddle Feeder assembly shall be easily accessible. It shall be possible to replace electrical, mechanical and hydraulic components of paddle feeder when in position. Various drive equipment and hydraulic/other components shall be so arranged that coal spillage from track hopper month does not accumulate near/over them.

1.6.2                 In-Line Magnetic Separator and Suspended Magnet

Inline Magnetic Separators shall be provided for continuous and automatic extraction and discharge of tramp magnetic pieces from coal being discharged from conveyors as specified. The sets shall be complete in all respects with drives, magnets, inline belts, hoppers, chutes, tramp-iron boxes and all electrical ancillaries like control panels etc. Suspended Magnetic Separator shall be provided for picking up tramp magnetic pieces from moving coal over Conveyor.

Magnetic core material shall be pure annealed iron or equivalent high permeability magnetic material.  The coil shall be of aluminum wire with class ‘H’ insulation, to limit the absolute temperature of the winding to 140 deg. centigrade. The ILMS shall be oil cooled.

The ‘Force Index’ i.e. the product of flux density in gauss and rate of change of flux density w.r.t. distance, at the bottom of falling material trajectory shall be 100,000 (gauss x gauss/inch) minimum in hot condition for mounting height of 400 mm.  However, the strength of the magnet shall not be less than 1000 gauss in hot running condition at 400 mm distance. The minimum strength of the magnet shall be 1000 gauss at the specified mounting height through out the burden width.

Mounting height of 400 mm shall be taken between top of conveyor belt or bottom of falling material trajectory and the surface of magnetic separator belt.  Characteristic curve of magnet with the value of flux density varying between 50 mm to face of conveyor belt shall be provided.  The cross section of magnet shall be suitably designed to provide sufficient area for magnetising the coil effectively covering full cross section of the discharge material.  The magnetic separator shall be located such that it picks-up tramp iron from coal trajectory after it has been discharged from head pulley.

The tramp magnetic pieces picked up by the magnetic separator shall be discharged suitably to ensure that it falls into the tramp iron chute, which shall be provided upto ground level. All conveyors with magnetic separator at head end shall have non-magnetic SS pulleys & shafts.

The motor and the gear reduction unit for driving the in-line belt shall be adequately sized with minimum 20% margin to avoid any over loading during operation.  Suitable zero speed switch shall be provided.

The belt shall be designed to withstand high temperature at the bottom of the magnet and any serious damage due to the impact of the sharp edges of the tramp iron.  The belt shall be provided with rubber cleats spaced suitably. The belt shall be of fire resistant grade.

The magnetic separator units shall be supported by suitable structural member from the top by taking support from the operating floor beams with turn buckle arrangement to facilitate the necessary adjustments during operation. Further, manual cross travel arrangement shall be provided to move the magnetic separator away to facilitate maintenance of the conveyor discharge pulley.

ON/OFF control push buttons with indicating lamps shall be provided at the local station. Both local and remote manual control shall be possible. The materials of chutes and hoppers associated with magnetic separators above the drive floor shall be SS-304 in the magnetic zone. Other chutes shall be of 1 mtr. sq. dimension and shall be made of MS. chutes shall have poking doors at all floors to clear jammed material.

Suitable arrangements shall be provided in the magnet for keeping the coil of the magnet dry from atmospheric condensation when the magnetic separator is not in use.

Following items of tramp iron are expected to be handled by the system:

                        Coal Sampling Unit

                        Coal Sampling Unit shall be complete with necessary samplers, crushers, flap valves, chutes, hoppers, belt feeders and sample collectors etc. to give samples from any of the two streams running at guaranteed capacity.

Coal sampling unit shall be automatic & provided at place specified elsewhere.

The coal sampling units suitable to give “Samples” conforming to ASTM-D-2234 shall be selected by the Bidder for taking samples from any of the two streams running at guaranteed capacity. The different Equipment selected for coal sampling unit shall be such that there shall be no loss of fines and moisture from the samples. The capacity, make and model of all equipments of coal sampling unit shall be subject to approval of Project Manager.

The normal input feed size shall be considered as (-) 250 mm for coal sampling unit before coal crushers (Ring granulators). However occasionally (-) 400 mm lumps may also arrive. Coal lump size after crusher (as fired coal) shall be (-) 20mm. However occasionally (-) 50 mm lumps may also arrive in as fired coal.

Primary samplers (separate for each conveyor) shall be rugged, able to withstand severe shock loads and operate trouble free.

Belt feeders shall be provided for entire sampling path upto sample collector. The feeders shall meter the flow accurately, produce a non-plugging condition and resist sticky and wet coal.

For rejects path also, belt feeders shall be preferred. Screw conveyors for the same shall be accepted only where space constraints do not permit distribution of coal rejects to receiving conveyors below.

Suitable sample crushers shall be provided for reducing the main input feed coal to 95% minus 8 mesh size and 100% minus 4 mesh size. Single stage crushing shall be provided. There should be no re-circulation of fines in the crushers.

‘Lot size’ shall be equivalent coal quantity handled in 8 hours operation assuming average conveyor loading at 75% of rated conveyor capacity. However sampling system shall also be suitable for taking one gross sample for each lot of “3500 Te” coal (approx. equal to one rake load).

Belt feeders shall be positively self cleaning and have dust tight construction. It shall be provided with flanged belt, rubber lagged head pulleys and inspection doors. No chain/belt drives shall be accepted.

The crusher’s base should be built of reinforced concrete and be sufficiently large in mass.

The primary / secondary samplers shall be of dust tight construction and self contained type.

The sample chutes shall have minimum valley angle of 60 degrees to horizontal and shall be of stainless steel plates. The welding of chutes shall be done externally only.  The inside surface of the material near welds shall be smooth. Radius at corners not less than 1″ shall be provided in chutework. All solid connected members shall be by means of bolting flanges with atleast 6 mm thick standard grade neoprene gasket material between the metal flanges. No control gates to regulate the flow of material shall be incorporated in the chute work.

The materials rejected from samplers shall be returned to main conveyor stream.

Minimum 4 nos. sample collecting bins shall be provided.  The bins shall be provided with air tight connection.

1.6.3                 Roller Screens

The Roller Screens shall be of mechanical type.

The roller screens shall be capable to segregate the (-) 20 mm size of coal alongwith coal dust, any muck & muddy coal (which is likely to be encountered during rainy season) etc. The segregated material shall  be directly fed onto the corresponding belt conveyors/feeders through separate hoppers/chutes  provided under each grizzly feeder.  The width of vibrating roller screen shall match to feed the material uniformly over  the entire length of crusher rotor without any deflectors in the feeding chute.

Inclination of the grizzly pan shall not exceed 10 deg. from horizontal.

The equipment shall be designed in such a manner that choking does not occur during operation, particularly during rainy season when the coal gets sticky.

The deck of vibrating roller screens shall have continuous solid deck section in the impact zone under direct coal fall and remaining deck shall be fitted with grizzly bars. The solid deck section shall be provided with replaceable tiscral or eqvt. liner plate of adequate thickness.  The grizzly bars shall be wear resistant. The bars shall be rigidly fixed with main frame along with the length of grizzly deck.

The vibrating roller screens shall be mounted on the floor with the help of helical springs made of alloy steel.  No rubber/synthetic material for the support shall be acceptable.

Vibrator bearings shall be grease lubricated, double spherical roller type suitable for vibrating equipment.  The bearings shall be sized for minimum 8,000 hours of operation.  Bearing calculations shall be furnished during detail engineering for Owner’s approval.

Suitable sealing arrangement shall be provided between the vibrating structure and chute work to avoid dust nuisance in the surrounding area.

Proper arrangement to avoid dust ingress into lubricant of eccentric shafts shall be provided.

In case of V- belt drive to avoid loosening of  sheave mounted on eccentric shaft, suitable arrangement like taper bush or coupling shall be provided.

1.6.4                 Crusher and Vibration Monitoring System 

The Crushers of 800 T/H shall be provided. The crusher shall be of ring granulator type such that the crushing action is accompanied by the minimum of attrition. Uniform crushing impact shall be assured. The Crusher  shall  be   suitable   to handle coal with size of (-) 250 mm (occasionally 1-2% coal shall be –400mm size.) 98% output of the crusher shall be down to (-) 20 mm.

Maximum crushing efficiency shall be of obtained, i.e., thermo dynamically, the ratio of surface energy produced to the kinetic energy expended should be maximum.  Accordingly, the number of central discs along the rotor shaft shall be maximum with minimum spacing in between.

The crusher shall be capable of delivering the normal rated output even when handling damp sticky coal having maximum moisture content.  No clogging or building up of material on the crushing element shall develop. The material for major components of crusher shall not be inferior to the quality and standards as mentioned below:

                        VIBRATION MONITORING SYSTEM FOR COAL CRUSHER

Vibration monitoring system should be offered for crushers as indicative below :

                        ———————————————————————————————-

                        Sl.No.  Equipment            Type  No.      No. of              

                                                                                                *locations         

                                                                                                per Equipt.

                        ———————————————————————————————-

                        1.         Coal Crusher        Radial              4        2                     

                                                ring                                                                  

                        ———————————————————————————————

            * Vibration shall be measured at each location in Horizontal as well as           

               vertical direction.

1.6.5                 Belt Conveyors System

Design of belt conveyor system shall be suitable for coal parameters specified elsewhere.

Slopes of conveyors, wherever applicable, shall not exceed 15 deg. depending on the lump size, and other governing factors.

The guaranteed capacity of all conveyors shall be the rated capacity.

All conveyors (except boom conveyor of S/R) shall be designed for 110% of rated capacity. The boom conveyor of S/R shall be designed for 125% of rated capacity. Design capacity of the conveyor system shall be considered for the selection of belt width, belt speed and the continuous motor rating at 50oC.

The drive chain equipment’s for various belt conveyor systems shall consist of drive motors, fluid couplings, gear reduction units, low speed flexible couplings and pulleys. 

Conveyors and belt feeders shall be provided with electro hydraulic thrustor brakes to adjust the coasting time of conveyors such that there will not be any build up of material in the chutes. Further conveyor shall come to halt as early as possible.

Belt conveyor system shall be designed as per the latest edition of ‘Belt Conveyors for Bulk Materials’ published by Conveyor Equipment Manufacturer’s Association’ or equivalent International Standard.

1.6.5.1              Construction Requirement

                        Belting

The belting shall be of either synthetic fabric such as Nylon/Nylon, Polyester/Polyamide etc. with rubber covers of adequate flexibility to give a troughing angle of 35 deg. For all the conveyors the number of plies, cover thickness, factor of safety etc. shall be as per the recommendation of belt manufacturer, but not inferior to the followings:

                        Belting 

                        Type                                        Synthetic Fabric of Nylon / Nylon,

Polyester / Polyamide, etc.        

                        Cover Grade                             Fire resistant      (Conforming to Canadian 

standard association CAN/ CSA M-422- M87 Grade – C.     

                        Cover Thickness (without -ve tolerances).

                        (a)        Face                             5.0 mm (min.)              

                        (b)        Bottom                         2.0 mm (min.                           

                        No. of plies                               Minimum 4                              

                        Drive Arrangement       

                        i) Snub drive                             For motor ratings upto 160 kW and         for

motor ratings above 320 kW.     

                        ii)  Dual tandem drive                 For motor ratings not covered above.     

                        Factor of Safety             10 (Minimum)              

                        Normal Working tension             Less than 80% of max. allowable

                        at design capacity                       working tension            

Carrying idlers shall be provided with three equal rolls with troughing angle of 35 deg. and 2 deg. forward tilt (except in case of reversible conveyors).

In no case, shall the diameter of the idler roll be less than 152 mm for both carrying side and return side.

Roller used in idlers shall be made from ERW steel tube.  Wall thickness shall be minimum 4.0 mm without any negative tolerance. The rollers shall be mounted on EN-8 or equivalent material spindles by means of heavy duty ball bearings, preferably seize resistant type (SKF/Equivalent), of 30 mm size for carrying idlers and 20 mm size for return idlers. The bearings shall be adequately sealed and lubricated for life. The rolls shall be supported from fabricated steel brackets. Fixing arrangement of rollers with brackets shall be drop-in type. For adjusting the alignment of the idlers, slotted holes shall be provided in idler supporting base plates.  Direction of belt travel shall be clearly marked on the brackets of carrying idlers.

Idler rollers shall be waterproof, dust proof and weather proof against a high velocity water jet.  All idlers shall be provided with minimum tripple labyrinth dust seal.

Impact idlers used at the loading and transfer point shall be so designed as to avoid direct loading impact, belt damage and excessive punishment to the carrier. The material used in construction of this type of idlers shall be of resilient type.

The return idlers for all conveyors shall be single roll type.  For conveyors longer than 400m, two roll return idlers with 10 deg. troughing angle shall be provided.

The self-aligning idlers shall be direct acting type, complete with actuating rollers fitted with the ball bearings and mounted inclined towards the belt.  The idler frame shall be suitably cradled about a vertical pivot, supported in bearing over a fixed plate.  Adequate sealing arrangement shall be provided to prevent contamination of the lubricant by dirt and moisture.

Transition type troughing idlers shall be used adjacent to all pulleys to permit proper support of the loaded belt near the pulleys without excessive stretch of the belt edges. The transition idlers shall be provided with preferably adjustable concentrator (end) rolls and long center rolls to suit the troughed belt contour between the last regular troughing idler and the adjacent pulleys. The transition length and the number of the transition idlers shall be selected depending upon the tensions, type and size of belt, number of plies and other necessary governing factors.

All the conveyors shall be provided with one self cleaning type rubber disc return idler located near the head pulley for cleaning the return belt.

Proper arrangement shall be provided in the brackets of all types of  idlers for preventing the rollers from coming out of the brackets during normal / abnormal conditions.

1.6.5.2              Belt Cleaners

                        External Belt Cleaner

Spring loaded scraper type cleaner with modular segmented and replaceable polyurethane scrapers blades complete with main cleaner, pre-cleaner along with accessories and necessary fines chutes shall be furnished for all belt conveyors, tripper head pulley and belt feeders at discharge pulleys. The modular units shall be easily replaceable. The scraper assembly shall be easily maintainable from outside without any interference with the chute arrangement and assembly.

                        Internal Belt Cleaner

V-plough type belt cleaner made of mild steel flats and hard rubber strips with automatic wear adjustment and necessary accessories shall be furnished for cleaning internal surface of the conveyor belt.

1.6.5.3              Belt Take-up Arrangement

Automatic take-up of gravity type shall be generally provided with necessary take-up arrangements complete with bend pulleys, take-up pulley, with its supporting / sliding assembly, wire ropes for suspending the separate take – up weight sliding assembly close to the ground, counter weights and other accessories. Suitable guards, marked up scale attached to the frame to monitor belt stretch and access/maintenance platforms with handrails all around etc. shall be provided.  Adequate access from conveyor gallery/transfer house/ground etc., as the case may be shall be provided to inspect, repair and maintain the gravity take-up arrangement. Suitable arrangements shall be provided for clearing accumulated coal from various platforms to ground level. Guides of take up pulley/counter weights shall be sufficiently strong so that they do not bend during belt snapping.

The prime consideration should be to locate the automatic take-ups at a place where these will work best, in relation to the drive, to keep belt tension at a minimum.  Other considerations such as available space, maintenance considerations and the economics of the location should also be taken into account while designing.  Take up shall not be located over buildings..  Height of take-up guide structure shall be sufficient to allow the take-up weight movement up and down for all operating conditions of conveyor and to allow minimum two (2) vulcanising lengths margin in the belt or percentage of conveyor length (2.5% for synthetic belting) whichever is larger.  Suitable guides shall be provided both for take up pulley and take up weight.

Hoists with monorails for holding take-up pulley and weight in case of belt changing, vulcanising etc. shall be provided.  2 M safety fencing along with suitable gate and locking arrangement shall be provided around gravity take-up at the base level / ground level.

Irrespective of take-up location, the travel zone of take-up weight shall start from a suitable height above ground.

Suitable buffer arrangement shall be provided to arrest the fall of take-up pulley in order to avoid damage of the pulley assembly in case of belt snapping.  Similar buffer arrangement shall be provided for take-up weight also in case of take-up weight travel zone terminating above a building floor.  Suitable sandpits shall be provided at ground below the take-up weights.

In case of double stream conveyors, a partition of 3mm steel plate shall be provided between the two take-up pulleys along entire travel zone of take-up pulleys. Intermediate platforms shall be provided in the take-up zone for maintenance of take – up pulleys / counter weight.

Take-up weight shall consist of multi-blocks and not of single block to facilitate adjustment in weight if required during operation.  Weight of the blocks shall be in descending order and single heaviest piece shall be suitable for easy handling.

1.6.5.4              Hold Back Devices

Suitable hold back devices for preventing running back of the conveyor belt in case of conveyor being stopped in loaded conditions due to power failure or during normal operational delays shall be provided to give positive protection.  The hold back shall instantaneously engage without shock and be capable of protecting equipment and personnel.  It shall be released instantly when ‘power’ resumes or the ‘delay’ is removed.  The holdback devices shall be integral with gearbox.

1.6.5.5              Pulleys

Pulleys shall be provided as required for various conveyors. In determination of pulley diameter, no account shall be taken of the pulley lagging.  The nominal diameter and face width of the pulleys shall be as stated in IS:8531.

The snub pulleys on each conveyor shall be located to provide a belt wrap on the drive pulleys of not less than 220 deg. wrap is envisaged for single snub drive only.

All drive pulley surfaces shall be hot lagged with vulcanised natural rubber lagging grooved in diamond pattern.

All non-drive pulleys shall be vulcanised natural rubber lagged (hot) with plain lagging.

The rubber to be used for lagging of pulleys shall confirm to following specifications The rubber lagging of pulleys and method of lagging and testing the same shall conform to IS:4682.

                        Pulleys 

                        General (for all types of Pulleys)

                        (i)         Minimum shell               16 mm

                                    thickness          

                        (ii)        Minimum end disc                     24 mm

                                    thickness          

                        (iii)       Maximum allowable                   5 minutes

                                    deflection of shaft

                                    at the hubs       

(iv)       Pulley  shaft  diameter Margin of minimum 20% shall be considered on maximum tension for arriving at the shaft dia.

                        Drive Pulleys

                        (1)        Minimum shell thickness 16 mm

                        (2)        Lagging                         Hot lagged with vulcanised natural

            rubber

                        (3)        Lagging thickness                       12 mm thick grooved in diamond                                                                                                pattern with grooves 6 mm wide x 6                                                                                            mm deep          

                        (4)        Minimum angle of wrap 220° degrees

                        (5)        Maximum Out of                       0.5% of nominal diameter

                                    roundness        

                        Other pulleys

            (1)        Minimum shell thickness 16 mm

            (2)        Lagging                         Hot lagged with vulcanised natural

rubber

            (3)        Lagging thickness                       12 mm thick plain

                        Rubber for lagging

            (1)        Type                                        Natural rubber blended with styrene

butadiene rubber.

            (2)        Hardness                                   55 to 65 durometer (Shore A)

            (3)        Elongation                                 Over 300%

            (4)        Strength                                    160-200 kg/cm2

            (5)        Abrasion loss                             250 mm3 as per DIN 53516

            (6)        Specific Gravity             1.4 to 1.5

            (7)        Adhesion Strength                      10 kg/cm (minimum)     

                        Bearings for Pulleys

                        (1)        Type                                        Heavy duty roller type

            (2)        Casing                                      Horizontal Split Type    

            (3)        Sealing                          Dust tight with double labyrinth                                                                           seals.

            (4)        Lubrication                                Greasing arrangement with conical                                                                                  head shape nipples.       

                        Pulley Material                   Mild steel conforming IS:226 / IS : 2062.

The pulleys shall be made from mild steel conforming to IS:2062 (Tested Quality). However for conveyors with in line magnetic separators, at head end the pulleys and the shaft shall be of non-magnetic stainless steel.

All the pulleys shall be keyed to forged steel shafts of EN-8 or equivalent material of adequate proportion running in heavy duty roller bearings with proper greasing arrangement.  The plummer blocks for pulleys shall be of horizontally split type construction with minimum (4) nos. bolts holding the two split halves and with min (4) nos. foundation bolts.  The plummer blocks shall be dust tight with double labyrinth seals. Conical head shape nipples conforming to IS:4009, suitable drain plug and eye bolt shall be provided. Side covers of plummer blocks shall be heavy duty metallic sheets. No plastic components shall be used.

Pulleys shall be mounted on machined & ground surfaces.  Suitable guards shall be provided for all tail pulleys and bend pulleys for safety of operating personnel.

Suitable stiffening arrangements shall be provided in all pulleys.  For selection of pulley shaft dia of all the pulleys, a margin of atleast 20% shall be considered on the maximum tension.  Selection of pulley diameter, shell thickness, stiffening and shaft diameter shall be subject to approval of Project Manager during detailed engineering.

Pulleys of same diameter shall be completely interchangeable in totality and component wise. To have interchangeability of same diameter pulleys procured under separate contracts for a station, the bearing center distance of pulleys shall be subject to approval of the Owner. The adjustments required shall be done by the Contractor at no extra cost to the Owner.

1.6.5.6              Belt Protection Equipment

            a)         Pull chord Switch

Pull chord type (manually reset type) emergency stop switches shall be located on both sides of belt conveyors along the walkways for the entire length of conveyors for emergency stopping of conveyor at spacing of 30 Meters. The enclosure shall be of cast aluminum with degree of protection IP-65. It shall have a separate terminal box with a separate hinged cover which shall be totally sealed from main box containing actuating mechanism / limit switch etc. Local pull chord actuation shall be provided by means of mechanical flap. Each switch shall have two NO and two NC contacts, which shall be wired out to the terminal block. The terminal block shall have facilities of cable looping. The Contact rating of the switches shall be rated for atleast 5 Amps, breaking at 240 VAC at 0.3 p.f. lagging. Adequate length of rope and all accessories shall be furnished.

            b)         Belt Sway Switches

Belt sway switches of self resetting type shall be furnished one pair at 50 meter intervals to limit belt sway to permissible extent. The enclosure shall  be of cast aluminum having degree of protection of IP-65. It shall have a separate terminal box with a separate hinged cover totally sealed from the main box containing actuating mechanism/ limit switch etc. Each switch shall have two NO and two NC contacts one for alarm and one for trip, which shall be wired upto terminal block. The terminal block shall have facilities for cable looping. The contacts of the switches shall be rated for at least 5 Amps. breaking at 240 VAC at 0.3 p.f. lagging.

            c)         Zero Speed Switch

Zero speed switch shall be non-contact (proximity) type electronic switch. Mounting arrangement/ location shall be such that operation, effective sensing distance, sensitivity etc. shall not be effected by accumulation of dust on rotating part or surface of probe. Adequate mechanical protection by means of non-metallic shields shall be provided on top of the switch to prevent any damage due to falling coal / metallic pieces etc. In built initial start up delay and nuisance, tripping delay through timers shall be provided. Each switch shall have two NO and two NC contacts wired out to the terminal blocks. The contact of the switches shall be rated for atleast 5 Amps. breaking at 240 VAC at 0.3 p.f. lagging. The monitoring unit shall have cast aluminum body having IP-65 degree of protection. A separate terminal box with a separate cover, which shall be totally sealed from main box, shall be provided. Terminal blocks shall be suitable for terminating 1.5 mm sq. standard copper cable.

            d)         Under belt switch

These switches shall be installed under the belt for detecting the presence of material on the belt whose contacts shall in turn be used for operating solenoid valves of dust suppression system elaborated elsewhere. The switch and its operating arrangement shall be suitable for working in dusty areas. The minimum degree of protection of switch shall be IP-62. The switch shall be capable of detecting three events simultaneously as follows :

i)          Belt loaded

ii)         Belt running at more than preset speed.

iii)        Preset initial start delay.

            e)         Chute Blockage Switches

One no. chute blockage switch of proven type (subject to approval of the Employer) shall be provided at a suitable height on each leg of the conveyors chute nearest to the skirt boards. Chute blockage switch shall trip the feeding conveyor in case of Chute blockage and protect the feeding conveyor equipment.

The switch and its operating arrangement shall be suitable for working in dusty areas.  The minimum degree of protection of switch shall be IP-62.  Local indication of chute blockage switch actuation shall also be provided.  Location of chute block switch shall be such that washing/cleaning of chute by pipe / rod does not affect it.

1.6.5.7              Drive Equipment

Rating of all drive motors of conveyors shall not be less than 120% of the power required at drive motor output shaft at specified design capacity.

                        Suitable Drive Chain Equipment’s like electric motors, gearboxes (where applicable), fluid couplings (where applicable), flexible couplings and other accessories shall be provided for all the belt conveyor systems, paddle feeders, vibrating grizzly feeders, vibrating feeders (if applicable), crushers, mobile trippers, various pumps of dust suppression system, fans for ventilation system, monorail electrical hoists and other equipment’s specified in this specifications.  Various requirements as spelt out in the Technical Specifications for individual equipment’s shall be taken into consideration while designing the associated drive chain equipment’s.

                        Gear Boxes

Gear Boxes shall be of sealed type and mounted on machined or ground surfaces.

The gearboxes shall be designed for 24 hours continuous duty.   For thermal and mechanical rating of the gearbox the data sheet shall be referred to. Gearboxes with cooling coils are not acceptable.

The gears used shall be helical conforming to IS:3681 (latest revision) or worm reduction units or spiral bevel speed reduction units conforming to suitable Indian Standards.  The dimensions of the shaft end shall conform to IS:3688 or its latest revision.  Above 40 kW drive rating, all gearboxes shall be helical or bevel helical type only.

Recommended oil grade shall be compatible with gear internals like material of bearing, cages. Further, all gearboxes shall have suitable breather plugs.

                        Couplings

                        Flexible Couplings

Approved type of couplings shall be used for power transmission depending upon duty requirements.  The design of the coupling shall be such that it can take shock and misalignment without sacrificing its efficiency.  Flexible couplings shall be provided on low speed side of gearbox for all conveyors. Flexible couplings shall be geared type.

                        Fluid Couplings

Fluid couplings shall be provided in all the drive machinery for belt conveyor systems and coal crushers if the actual power requirement at motor output shaft is more than 30 kW.  The fluid coupling for LT motors shall be of traction type.  Cooling water coils for traction type fluid coupling shall not be accepted.  Scoop tube type fluid coupling shall be provided for conveyors with HT motors and coal crushers.  Suitable electrically operated actuators shall be provided for scoop tube operation from local as well as remote.  Suitable provision for alternate manual operation shall also be kept.  If required by the equipment designer, separate pump with motor shall be provided for circulating the fluid coupling oil through oil cooler.  Independent arrangement for forced cooling water supply using 2X100% capacity pumps to oil cooler shall be provided by bidder.  Suitable interlock using flow switches shall be provided in both oil as well as water lines to trip the drive motor in the event of flow in either lines falling below/ acceptable levels.  Suitable pressure indicators and flow indicators shall be provided in the cooling water lines along with all relevant valves, strainers and accessories.  Necessary interlock shall also be provided so that the HT motor cannot be started from remote / local unless position of scoop tube permits no load start of the motor. Tripping of downstream equipment while the system is under normal operation shall result in scoop tube re-positioning to permit no load run of the concerned HT motor.

1.6.5.8              Conveyor Galleries

All overground and overhead conveyors shall be located in suitably enclosed bridge structure.  Structural steel bridges of adequate width and depth (3000 mm clear head room for under ground and 2700mm for overground) shall be provided complete with conveyor bottom deck plates, seal plates, walkways of chequered plates with anti-skid arrangement(s) hand rails (on both sides of each conveyor belt except where equipment like paddle feeders, stacker/ reclaimers, trippers etc. traverse over conveyor), conveyor supports etc.

The conveyor bridge shall have permanently colour coated steel sheeting covers on roof and both sides, properly screwed or locked to steel structure as required.  Adequate provision of windows shall be kept.  A continuous slot opening of 500 mm shall be provided on both sides just below the roof sheeting.

The floors of outdoor conveyor galleries shall be designed and constructed as follows:

All conveyors shall be provided with 12 G steel seal plates throughout the length of the conveyor gallery in such a way that complete gallery bottom surface area forms a single water proof floor. It is envisaged to clean the conveyor gallery with water periodically.  All the water / coal slurry  shall be suitably guided to down comers (min 300 mm dia) provided at every trestle. Each downcomer shall lead the coal slurry into a 2 m3 brick wall tank at ground level having 2 Nos. decanting taps at suitable elevations. Decanted water shall be led to the nearest storm water drain of the Owner.  Necessary arrangement shall be provided to avoid choking of downcomers by bigger coal lumps and for cleaning of choked downcomers.

The conveyors shall be provided with continuous steel decking plate of minimum 3 mm thickness.

Structures and floors shall be so designed as to provide suitable space for routing of 200 NB fire fighting pipe with water, and conduits. Power and control cables shall be routed outside conveyor gallery.

Steel trestles to support the conveyor bridge shall rest upon concrete foundations to be provided by the Contractor.  Complete trestle structures shall also be supplied by the Contractor. Suitable approach/access platforms with handrailings shall be provided to approach the conveyor gallery (like in case of fire) through monkey ladders on the trestles. Suitable wire mesh doors on steel frame construction lockable from outside only shall be provided in the conveyor galleries at these locations. All monkey ladders shall have cage for safety of personnel using them.

The width of conveyor galleries shall be decided by the Bidders depending on the equipment’s size and the walkway width as specified.

Provision shall be kept with platforms and ladders for crossing over the conveyors at approximately every 100m intervals of route length and min. one per conveyor.  Further provision shall also be kept with platforms and ladders for atleast two (2) crossings over the track hopper. Walkways shall be kept as follows:

                        Walkways

            (a)        Construction                  Chequered plate with antiskid arrangement.

Chequered plate steps shall be provided where conveyor slope exceeds 10 degrees. (Totally sealed so that no water falls down while washing.)         

            (b)        Central walkway            1100 mm clear (no infringement allowed)

                        width

            (c)        Side walkway    800 mm clear (no infringement allowed)

width                            (for single conveyors, the width of side walkways shall be 800 mm on one side and 1100 mm on the other). (no infringement allowed)

                        Side Windows              

            (a)        Spacing (Center             25.0 m on each side (in staggered

                        to center)                      fashion)

            (b)        Size                              1.5 m x 1.5 m   

            (c)        Window material           Refer Civil Section

1.6.6                 Stone Picking

Manual Stone Picking arrangement at a suitable location in the conveyor gallery before the primary crusher house shall be provided complete with platforms, overhead lighting, hand railings, suitable seating & holding arrangement for manual pickers and disposal chutes to ground level etc.  Four (4) nos. manual pickers (two on each side) shall be positioned for each belt.  Each manual picker shall cover 3 m long belt stretch adjacent to each other.  The picked up stone lumps (upto 600 mm size) shall be collected over the conveyor gallery walkway level from where these stones can be pushed into the hopper/chute upto disposal trolley at the ground level.

1.6.7                 Belt Vulcanizing Machine

Belt Vulcanizing Equipment shall be suitable for hot vulcanizing of belt splice and shall be of easy-to-handle type.

Equipment should be suitable for vulcanizing of entire splice width in single setting.

Equipment should be capable of applying uniform pressure over the splice by pneumatic or hydraulic means.

                        Heating element should be preferably of flexible type.

1.6.8                 CHUTES AND HOPPERS

                        Chutes & Hoppers, flap gates and rack & pinion gates shall be furnished alongwith all necessary accessories, electricals etc. shall be provided to ensure proper flow/storage/bifurcation of coal as per system requirements.

The minimum valley angle of chutes shall be 60 degrees from horizontal. The actual valley angle and chute design shall be finalised after carrying out coal flowability studies at worst conditions.

Transfer chutes shall be adequately sized and sloped to ensure smooth flow of coal without any accumulation anywhere.

Complete chute work above the drive floor for conveyors provided with ‘In-line belt magnetic separators’ shall be of 10 mm thick  SS – 304 in the zone of magnetic field.

Direct impact of material on conveyor belt shall be avoided by providing an inclined surface at 60 degrees valley angle at the feeding point to guide the material in the direction of belt travel.  Further, chute construction below flap gate shaft shall be such that there will not be any accumulation of coal dust between chute and flap gate in that zone.

Hoppers and Chutes shall be made of minimum 10 mm thick TISCRAL/MS or equivalent with adequate stiffeners.  Long chutes guiding flow from considerable height shall be provided with impact plates wherever change in direction of flow takes place. Hinged inspection doors (generously sized) of leak proof construction shall be provided for access/ maintenance purpose, at approachable heights, of the chutes. All chutes should have one inspection door at every floor and for the ones in between the floors, suitable access ladder and platform etc. shall be provided. Maximum distance between two inspection doors in a chute shall be 2 mtrs. For sealing at inspection doors labyrinth type arrangement (with rubber inserted in grooves) to be provided. In addition to mounting bolts, swiveling eccentric handle(s) to tighten the door further against rubber shall also be provided.

Bottom side of the chutes on which the coal slides shall be welded to the side plates to form a trough. Bottom sides along with its adjacent sides shall be flanged and made from TISCRAL  or equivalent  material of 10 mm thickness. The non striking surface i.e. the covers of the trough shall be of 10 mm thick mild steel and bolted to the flange provided on the trough. Inside welding shall be provided in the corners for permanent sealing. Further, the chute boxes not more than 1.5 m in length shall be joined through bolted flange connection to form the chute legs.

Bolted flange joints shall be of dust tight construction and necessary sealing material shall be provided in all the flange connections for adequate sealing.

Complete chute work in the region of flap gates shall be fabricated from TISCRAL or equivalent. In case of vertical chute (valley angle more than 80 degree) complete chute, work shall be of 10 mm thick TISCRAL or equivalent material. While finalising the chute work inside the building, arrangement for shifting and replacing chute legs, proper handling arrangement/wall openings, trolleys, hoists shall also be provided.

Hoods over the conveyor head pulleys shall be made of suitably stiffened minimum 4 mm M.S. Plates and shall be provided with hinged and gasketed inspection doors with suitable access to them.  Further, rubber seal shall also be provided at the very inlet of head chute to minimise dust nuisance. Minimum size of chute shall be kept as 2/3^rd of belt width or 1000X1200 mm which ever is higher.

1.6.9                 Skirt Boards

Skirt board shall ensure centralised loading of conveyor belt to avoid coal spillage. Suitable ‘Skirt Plates’ of minimum 3.0 meters length shall be provided at each feeding point of conveyor. The width of the Skirt Boards shall be two-third the conveyor belt width.  In the belts before Crusher House where coal of appreciable lump size (250 mm) is being conveyed, the gap between the bottom of the skirt board and the belt shall be made to increase uniformly in the direction of belt travel. The height of the skirt boards shall be sufficient to contain the material volume as it is loaded on the belt and shall not be less than 750 mm. The skirt plates shall be fitted with modular segmented and replaceable rubber skirting pads having facility of adjusting the pressure on the belt conveyor and shall have provision of on line removal for the purpose of easy maintenance. Such segmented rubber pads with its holding down adjustment arrangements shall be of proven design. The edges of segmented pads shall be installed at an angle for providing a better seal.  All care shall be taken while designing, to combine good sealing with minimum belt wear.

1.6.10               Flap Gates

The motor operated two position flap gates shall be provided in transfer chutes as specified and shall be complete with electrically operated actuators. The gates shall be of robust construction and suitable for trouble free operation. The face of the flap gate shall be mode out of 10 mm thick TISCRAL or equivalent material.

The equipment shall be capable of being operated for at least 15 switchings per hour at rated load and thrust and shall be suitable for 10 Nos. consecutive switchings at rated load and thrust.  The equipment shall be shop tested to prove this requirement.

The motor rating for the actuator shall be so selected as to provide sufficient thrust for operation of the flop gates against the moving weight of coal and/or flap gate. The flap gate travel shall be in the range of 60 deg. to 70 deg. The motor shall be completely dust tight.

Lever arm shall be provided between actuator and flap gate shaft for obtaining required thrust.

The actuators shall be capable of preventing any over travel.  Suitable travel dependent limit switches controlling the travel of the flop gates on either direction shall be furnished.  These shall be placed internal to the drive unit and shall be completely dust-proof. The limit switches shall be capable of adjustments to vary the total length of travel of the gates.

Suitable thrust dependent limit switches shall be provided in the actuator, which shall trip off the actuator motor in case of excessive thrust due to jamming of the gates during its travel in either direction.  The same shall also be integral to the drive unit and shall be dust proof.

Provision for alternative manual operation shall also be made using declutchable handwheel. The diameter of handwheel shall be selected considering convenient force to be applied by a single operator. However, minimum diameter of hand wheel shall be 500 mm. Limit switch for safety of person operating the hand wheel shall be provided.

All the two way chutes, one way of which is leading towards the future conveyor, shall be provided with blind flange and flap gate with a provision to mount an actuator in future.

All the actuators in the plant should be selected based on heaviest loading, but the rating shall not be less than 2500 kg with a lever arm of 1.0 m in any case.

Suitable stiffening arrangement shall be provided between the two faces of the gate plate.  At the end of the travel the total length of edge of the flap gate shall rest on a suitable projected surface from chute to prevent leakage of coal dust through the available clearance between chute and flap gate.

Maximum feasible counterweights shall be provided for better utilisation of system.

Suitable self aligned double row ball bearings in dust tight housing shall carry the gate shaft.  Suitable provision for regreasing shall be provided.

For standardisation purposes, only one standard type of actuator for flap gates shall be provided. The standard type actuator shall be selected for maximum thrust as calculated for various locations. Flap gate actuator as a whole and individual component wise shall be completely interchangeable for all locations.

The material of shaft shall be EN-8 or equivalent. The diameter of the shaft shall be suitable for  motor stalled condition and associated twisting.

Approach/maintenance platforms complete with the chequered plate floor, hand rails, ladders etc. shall be provided for all flap gates.

Shaft & flap gate shall be tightly fitted to each other.

On both faces of flap gate main plate, 10mm thick TISCRAL liner plate or equivalent material shall be provided.

The motor operated two position flap gates shall be provided in transfer chutes as specified and shall be complete with electrically operated actuators. The gates shall be of robust construction and suitable for trouble free operation. The face of the flap gate shall be mode out of 10 mm thick TISCRAL or equivalent material.

The equipment shall be capable of being operated for at least 15 switchings per hour at rated load and thrust and shall be suitable for 10 Nos. consecutive switchings at rated load and thrust.  The equipment shall be shop tested to prove this requirement.

The motor rating for the actuator shall be so selected as to provide sufficient thrust for operation of the flop gates against the moving weight of coal and/or flap gate. The flap gate travel shall be in the range of 60 deg. to 70 deg. The motor shall be completely dust tight.

Lever arm shall be provided between actuator and flap gate shaft for obtaining required thrust.

The actuators shall be capable of preventing any over travel.  Suitable travel dependent limit switches controlling the travel of the flop gates on either direction shall be furnished.  These shall be placed internal to the drive unit and shall be completely dust-proof. The limit switches shall be capable of adjustments to vary the total length of travel of the gates.

Suitable thrust dependent limit switches shall be provided in the actuator, which shall trip off the actuator motor in case of excessive thrust due to jamming of the gates during its travel in either direction.  The same shall also be integral to the drive unit and shall be dust proof.

Provision for alternative manual operation shall also be made using declutchable handwheel. The diameter of handwheel shall be selected considering convenient force to be applied by a single operator. However, minimum diameter of hand wheel shall be 500 mm. Limit switch for safety of person operating the hand wheel shall be provided.

All the two way chutes, one way of which is leading towards the future conveyor, shall be provided with blind flange and flap gate with a provision to mount an actuator in future.

All the actuators in the plant should be selected based on heaviest loading, but the rating shall not be less than 2500 kg with a lever arm of 1.0 m in any case.

Suitable stiffening arrangement shall be provided between the two faces of the gate plate.  At the end of the travel the total length of edge of the flap gate shall rest on a suitable projected surface from chute to prevent leakage of coal dust through the available clearance between chute and flap gate.

Maximum feasible counterweights shall be provided for better utilisation of system.

Suitable self aligned double row ball bearings in dust tight housing shall carry the gate shaft.  Suitable provision for regreasing shall be provided.

For standardisation purposes, only one standard type of actuator for flap gates shall be provided. The standard type actuator shall be selected for maximum thrust as calculated for various locations. Flap gate actuator as a whole and individual component wise shall be completely interchangeable for all locations.

The material of shaft shall be EN-8 or equivalent. The diameter of the shaft shall be suitable for  motor stalled condition and associated twisting.

Approach/maintenance platforms complete with the chequered plate floor, hand rails, ladders etc. shall be provided for all flap gates.

Shaft & flap gate shall be tightly fitted to each other.

On both faces of flap gate main plate, 10mm thick TISCRAL liner plate or equivalent material shall be provided.

1.6.11               Rack & Pinion Gates

Rotary actuator operated rack and pinion gates shall be provided at various locations as specified. The gate shall be mounted such that coal load does not act vertically on gate.

Suitable manually operated rod gates shall be provided over rack and pinion gates for their easy operation and maintenance.

The rack and pinion gate shall be guided properly and suitable rollers with bearings sealed for life and dust proof shall be provided.

The rack and pinion gates shall be of mild steel construction with liner plate of 10 mm thick tiscral or equivalent material. The gates shall be operated by means of double rack and pinion.  The material for rack & pinion wheel shall be cast steel and shaft shall be EN.-8.

Provision for alternative manual operation of motorised rack and pinion gates shall also be made. Limit switch for safety of person operating the hand wheel shall  be provided.

Manual effort required to operate the rack and pinion gate shall not exceed 25 kg. Maximum time for closing/opening shall be 25 sec.

Approach/maintenance platforms complete with chequered plate floor, hand railings, ladder etc. shall be provided for all gates.

1.6.12               TRAVELLING TRIPPER AND BUNKER SEALING ARRANGEMENT

                        Mobile Trippers on bunker conveyors along with belt sealing arrangement shall be furnished and erected complete with rails, including necessary supporting structures, approach/ maintenance platforms with ladders and hand railings, trailing cables, all electricals including machine mounted local control panel & control panel on one end of Bunker, location of which shall be decided during detail engineering.

Complete Bunker Sealing arrangement shall be provided over the bunkers to prevent dust emission into tripper bay.

1.6.12.1                        Travelling Tripper

The Travelling tripper on bunker conveyors shall be motor driven type.  It shall consist of structures, supports, walkways, rails, belt scrapper with adjustable rubber strip, rubber lagged head and bend pulleys complete with shaft bearings, chutes, stops, limit switches, brakes etc.  The tripper shall have provision for dropping coal both sides of conveyor into the bunker and back to the conveyor for the purpose of skipping intermediate bunkers.  The rating of tripper travel motor shall be adequate to move the tripper smoothly either in same or opposite direction to belt direction under fully loaded conditions. Adhesive weight requirement and tractive effort calculations shall be subject to approval of Project Manager. Coefficient of adhesion shall be considered as maximum 0.15.  Minimum two drive axles shall be provided for tripper travel. Arrangement shall be provided at the starting point of the tripper to avoid folding of belt.

In case of tripper running at a speed more than its rated speed due to chute jamming or other reason, conveyor shall trip and annunciation shall appear.

Supply of adequate length of rails to cover the runway length for the motor driven tripper shall be included.  The supporting structures for the rails with necessary end stops shall also be supplied under this specification.  Suitable belt hold down guide pulley shall be provided over the concave curve of belt over tripper.

The Bidder shall include in his proposal necessary electricals for traveling trippers such as motorised cable reeling drum with trailing cables, cable trays for resting the trailing cables and end limit switches for protection against over travel of the tripper. The cable reeling drum and trailing cable of each tripper shall be suitable for the entire length of the bunker bay.  Mechanical track stops shall also be provided. The cables shall have copper conductors, proper insulating material and braided armouring in accordance with IS:691.   Complete Telephone Communication system between Travelling tripper and CHP control room is in Bidder scope.

The travelling trippers shall be provided with fail safe  A.C. thrustor operated brake of totally enclosed type which shall engage as soon as tripper travel motor stops. A.C. thrustor operated rail clamps with hand operation facility from either side of the tripper shall also be provided. The specifications of brakes and clamps are as discussed elsewhere.

For selection and specification of drive motor, gearboxes and all other equipment associated with tripper relevant clauses of this specification shall be referred to.

All drive equipment shall be selected based on 115% of actual power requirement at specified guaranteed capacity. Further complete drive equipment shall be suitable for minimum 60 starts/hours.

Monorail & electric hoist shall be provided for lifting conveyor drum to bunker floors. Monorail all along the bunker conveyor to facilitate maintenance of tripper shall be provided.

1.6.12.2                        Bunker sealing arrangement

The sealing belt shall be of suitable grade (minimum 2 plies) with 5 mm x 5 mm covers (fire resistant) in line with other conveyor belting.  The belt shall rest on 20mm MS round bars spaced at 150 mm provided over the bunker slot (minimum 1100 mm) on tripper floor for tripper conveyor.  Needed guide rollers, bearings, brackets, safety guards etc. shall be provided by the Contractor.  The bunker sealing arrangement shall keep the bunkers sealed and prevent dust emission into tripper room.  The width of the bunker seal belt shall be at least 100 mm more than the bunker slot opening. Separate openings shall be provided on the bunker floor of each bunker to measure level of coal in the bunker. Hinged dust sealed door / flaps shall be provided on these openings.

Suitable grating to be provided in between bunkers in the tripper travel zone. Tripper floor is by Purchaser. Openings on the tripper floor for level measurement will be provided by Purchaser. Opening size will be informed to successful bidder during the detail engineering stage.

Suitable dust cover shall be provided over tripper head pulley.  Serrated rubber seal shall be provided at open side to prevent dust nuisance. Suitable dust tight access doors shall be provided. Counter-weighted type belt cleaner shall be provided below the tripper head pulley for cleaning the carrying side of the belt.

The tripper shall run on rails (90 lbs/yard) with double flanged wheels.  Rails for tripper travel shall be mounted on supporting structure of respective conveyors.

Suitable system for monitoring position of tripper shall be provided.  In addition, travel end limit switches and end stops shall also be provided.

Suitable access platform of chequered plate with ladders, handrailing and walkways on both sides shall be provided for access/maintenance of equipment on tripper.  In addition, crossover platform shall be provided with tripper so that operator can cross the belt through the same.

Suitable rail cleaners shall be provided on leading and trailing edge of tripper for either track.

3mm deck plate continuous shall be provided below carrying idlers on the trippers.

For specification of flap gates/actuator on trippers relevant clauses of this specification shall be referred to.

            Walkway of 800 mm wide shall be provided on both side of the tripper

Provision shall be kept for automatic tripping of bunker bay conveyor in the event of travelling tripper getting dragged (i.e. travel speed in excess of rated speed).

1.6.13               Belt Scale

                        Belt weigh scale for measurement of coal flow rate and quantity shall be provided at specified locations. System shall be complete with flow rate indicator, totaliser, control panel etc.

The weigh scale shall be automatic and electronic type. It should be designed for continuous automatic weighing, metering and printing of coal flow.

Each belt weigh scale shall comprise of a belt weigh scale platform with minimum 4 nos. weighing idlers. It shall have unitised construction for ease of installation and shall be fully floating type (without pivot points). Minimum 4 nos. sealed load cells of precision strain gauge type shall be applied in tension to support the weighbridge. The load cells shall have 100% overload protection and shall be structurally safe upto to 250% of rated belt scale capacity.

Belt scale shall be electronic microprocessor based with its program stored in non-volatile memory.

It shall be provided with self diagnostic features for trouble shooting of the entire belt scale system.

                        Fully automatic zero and span calibration facility shall be provided.

The electronic systems offered by the Bidder shall include all signal conditioning, power amplifiers and printed circuits etc. The printed circuits shall be encapsulated against dust and moisture.

Belt scale shall be provided with flow rate, total quantity etc. Remote flow rate indicators shall also be provided on paddle feeders.

The flow rate indicator shall have minimum 4 digits. The flow totalizer should have 8 digits display scale with reset facility.

Complete belt scale system shall be suitable for 70°C ambient temperature and 100% relative humidity.  It shall be suitable for out door installation in a dusty area.  The electronic circuit enclosure, sensors housing shall be dust and watertight, explosion proof conforming to NEMA and NEC (National Electronic Code). The electronic printed circuits shall be encapsulated with epoxy or other suitable material for protection against dust and moisture.

Minimum three years battery back up power failure protection shall be provided.

Belt scale shall be designed for a range of 20% to 120% of rated capacity with an accuracy of atleast (+) 0.25 percent throughout its range. Belt scale provided in Stacker Reclaimer Boom Conveyor shall have an accuracy (in the horizontal position of Boom) of (+) 1 percent for the range of 20% to 120% of boom conveyor capacity.

                        Local panel for belt scale shall be of FRP material.

1.6.14               Travelling Stacker cum Reclaimer

Travelling Stacker cum Reclaimer operating in conjunction with reversible yard conveyor shall be provided as specified. Stacker-cum-Reclaimer shall be capable of both stacking and reclaiming complete with adequate length of rail track, cantilever boom conveyor, intermediate conveyor, support carriage with vibrating feeders (if required), boom hoist, reclaimer bucket wheel, control panel, operators cabin, electrical power distribution system, motorised cable reeling drum, adequate length of trailing cables etc.

The design capacity of the yard conveyor shall not be less than 110% of the rated (guaranteed) capacity. For bucket size calculations and boom conveyor capacity, a peak reclaim capacity  of 125% of rated capacity shall be considered. The drive train of yard conveyor consisting of motor, scoop type fluid coupling, gear box etc. shall be provided at both ends of the yard conveyor.  Both the drive train at each end of the yard conveyor shall run simultaneously in one direction and reversed depending upon stacking or reclaiming operation of the machine.  The continuous motor rating at 50°C Ambient of the drive motors to be provided on each side of the yard conveyor shall be 120% of the actual power requirement at motor output shaft.  The actual requirement at motor output shaft of both the motors at each end shall be calculated based on 75% of the total load demand at design capacity.

Stacker/Reclaimer shall be capable of operating at high wind velocities upto 65 km/hr. It shall also be able to withstand maximum wind velocity as indicated in “Criteria for Wind Resistant Design of Structures & Equipment” placed in the document on civil aspect, when it is not operating. An anemometer shall be provided which shall indicate the wind velocity in the control cabin.

Electro-hydraulic thruster operated rail clamp shall be provided for holding the stacker-cum-reclaimer. Suitable arrangement shall be provided for keeping the stacker-reclaimer in fixed stable position when the weather is stormy.

Stacker-cum-reclaimer shall operate on rail track of 52 kg/mtr. running for adequate length to cover the entire coal stockyard. The ratio of boom length (as specified) to the rail track gauge shall not exceed 5. Top of rail level shall be maintained at 1.0 m above the ground level, i.e., coal pile base level unless specified otherwise.  Suitable number of rail scrappers shall be provided.

The machine shall be mounted on traverse carriage provided with driven and non-drive wheels of cast or forged steel and double flange design.  The track wheels shall be combined in pairs in the track wheel bogies. The wheels shall rotate on self-aligning roller bearings. Between the motor and the gearing, electro-hydraulic thrustor brake shall be provided.

The reclaimer shall be traversed by manual control at any desired speed within its speed range. During stacking/reclaiming operation, the equipment travel shall be limited to its travel zone and shall automatically stop when the machine reaches the extreme ends of such travel zone.

The lower works of the under-carriage of the machine shall be designed to transmit load on the wheel sets of the travel carriage in such a manner that the equipment is stable during normal operating condition as well as during hazardous weather condition with maximum permissible variation in center distance of rails and rail top levels.  The rail mounting for under-carriage shall be four legged system with hydraulic/mechanical equalising arrangement to make it three point suspension system for the best stability during operation. The traverse carriage and the under-carriage shall be interconnected in a manner, which will permit uniform distribution of overloads even if the rails are not level.

The upper frame of the machine shall be designed in such a manner that minimum number of angular movement points affects the luffing operation.  In addition, the variation of moment/torque on slew bearing shall be minimum.  The ring bearings shall be dimensioned in such a way that all forces can be safely transmitted to the structures of the wheels.

The roller bearing slewing ring shall be sealed against penetration of water and dust.

Angular movement points (hinge points) namely between equalising beam and base frame, luff pivots and hydraulic cylinder hinge points shall be provided with maintenance free bearings requiring no periodic lubrication during entire life span of bearings.  Minimum life span of self lubricating type bearings shall be 25 years with average 10 hrs. daily operation.

The luffing motion shall be through hydraulic pumps and cylinders.  In case of more than one cylinder being used for boom luffing operation, necessary provisions shall be provided such that the differential oil pressure between two cylinders are always maintained within permissible limits, during luffing operation and as well as when the boom is fixed at any position.  In case of any undue increase in differential pressure, the hydraulic circuit shall trip and suitable alarm indication shall be provided before tripping.  The hydraulic system of luffing shall be such that in case of failure of hydraulic system due to leakage or any other reason the boom could be held in position.

The boom shall revolve by at least 210° about the center of the receiving hopper and discharge/reclaim material on/from both sides of track anywhere within specified radius of the boom.

The boom conveyor shall be of adequate design capacity to match with the rate of peak reclaiming by the bucket wheel.

Boom conveyor with 41 m length shall be provided with a Belt Weighing Scale with weighing accuracy (in the horizontal position of the boom) of  ± 1% for a range of 20% to 120% of boom conveyor capacity.  The belt scale shall provide only flow rate indication in the Operator’s Cabin on the Stacker/Reclaimer. 

The bucket wheel assembly shall consist of 8 numbers of buckets of cell-less design and stationary annular chute.  The bucket shall be of suitable shape and design, which will enable to empty out the material fully from the bucket, and to prevent spilling of the scooped material during transfer to boom conveyor.  The buckets shall be readily removable.

Bucket size shall be selected for peak reclaim capacity based on maximum 80% degree of fill with respect to water fill capacity of the bucket.  Further, not more than 50% of annular ring volume shall be considered as effective volume. Rate of bucket discharges shall not exceed 55 per minute.

The bucket wheel drive shall be complete with electric motor, reduction gear unit moving in oil bath and suitable coupling between motor and the gear unit. Bucket wheel drive system, structural members, mast, hydraulic system etc shall be designed considering completely wet coal with max. surface moisture. Adequate safety devices shall be provided to prevent overloading of the bucket wheel drive, particularly when wheel will get stuck-up in the stockpile. In such an event, the power supply of the drive shall get automatically cut-off. Suitable electro hydraulic thrustor brake shall be provided to avoid backward movement of the bucket wheel after the power supply is cut-off and during maintenance work.

The boom conveyor with bucket wheel assembly, the mast and counter weight mounted on the upper structure shall rotate on the bearing ring.  The drive mechanism shall consist of the gear rim and drive unit shall comprise of motor, safety coupling, gearbox and pinion.  Protective devices against overloads shall also be provided.  The slew speed shall be variable. Boom conveyor shall be provided with self-training arrangement of latest design to avoid belt sway in the boom conveyor.

One tripper shall be furnished for stacker-cum-reclaimer unit for working in conjunction with the yard conveyor. The tripper & intermediate conveyor shall be complete with supporting structure, walkways, platforms, railing, belt scrapper, head pulleys, bend pulleys, hold-down pulley, chute and support with adequate number of wheels in bogie construction travelling on the same rails as those of the stacker-cum-reclaimer.

The intermediate conveyor will be skewed longitudinally to enable to receive material (during stacking) from tripper conveyor.  The intermediate conveyor shall be of adequate capacity to match with the design capacity of stacking which shall be 110% of rated capacity of stacking.  For other details, the relevant clauses of belt conveyor system of this specification shall be referred to. The intermediate conveyor shall be completed with supporting structure, walkway, railings, platforms, belt scrappers, head pulley, tail pulley and necessary chute work.

Group-wise lubrication system shall be provided combining different zones of lubrication points under different groups depending upon location and number of lubrication points.  Each group lubrication unit shall be independently functional through separate pump (motorised), grease container, valves, metering devices, pipes and other accessories etc. Preferably, the grease entry into various lubrication points shall be vertically downwards. The grease container shall have adequate capacity for supply of lubricants to all points and grease quantity for the points to be greased shall be adjustable. Further, all the lubrication points shall be easily accessible.

The stacker-reclaimer shall receive power through trailing cables. Separate motorised cable reeling drums for power and control cable shall be provided with arrangements for winding and rewinding of the cables.  The trailing cables shall run in a cable tray.  Further, the trailing cable arrangement shall be such that the cables run in-between the track rails. Cushion shall be provided in the cable reeling drums for about 30 m extra cabling length.

Complete telephone communication system between stacker-cum-reclaimer operator’s cabin and main coal handling plant control room shall be provided.

Limit switches shall be provided to prevent traverse movement, slew and hoisting etc. beyond the respective safe extremities.  Interlocking shall also be provided for S/R rail clamps and travel motors.

Travel drive equipment and slew drive equipment shall be suitable for 150 starts/hr. with continuous reversals.

                        Hydraulic control shall be provided for :

(a)        Hoisting/luffing

(b)        Operator cabin level adjustment

(c)              Equalising arrangement for travel carriage (in case of hydraulic

equalising)

Axial piston pumps shall be provided for pressurising hydraulic control fluid.

All drive equipments shall be selected based on 120% of actual power requirement at specified design capacity.

In addition to the requirements elaborated above, the structural design of the stacker-reclaimer shall be supplemented by following standards:-

ISO 5049/1       : Mobile Continuous Bulk Handling Equipment.

FEM                 : Federation Europeanne De La Manutention Section-I –

  Rules for Design of Hoisting Appliances.

Suitable RCC platform to be provided at one end of travel of the stacker-cum-reclaimer to rest the head end of the boom while either under maintenance or out of operation.

            The under-carriage shall be fabricated of steel plates and section.

The wheel mounting arrangement shall be such that the wheels can be dismantled easily from their supports.

800 M wide walkways with hand railings shall be provided on both sides of boom conveyor.

The upper structure shall consist of rigid box type steel plate construction on which the super-structure supporting mast, boom with bucket wheel and counterweight boom with ballast are erected.  The upper works shall be mounted on under-carriage by means of large diameter ring bearing of double roll roller type.

The boom shall be fabricated from rolled steel plates and sections and shall be of luffing type.

The counterweight boom with ballast, which balances the boom conveyor, shall be mounted on the upper structure and shall be suitably dimensioned.  The counterweight boom shall be fabricated with rolled steel plates and sections.  Suitable boxes shall be provided for placing the counter weights.

The stacker-reclaimer shall be provided with one enclosed dust proof & air conditioned operator’s cabin and so located as to enable the operator to get clear vision of both sides of the track and the field of operation. The cabin shall be suitable for operation in monsoon and tropical conditions and the inside ambient temperature shall be maintained at 27°C. The cabin shall be provided with toughened glasses with wipers and the arrangement shall be such that glasses can be cleaned from outside without any scaffolding. Cabin door shall be provided with hydraulic door closures. The cabin shall be kept in horizontal position through hydraulic cylinders irrespective of the angle of inclination of the boom conveyor. All controls for operation of all parts of the stacker-reclaim unit shall be provided in the cabin within easy reach of the operator. Lights and fan for operator’s cabin and adequate number of floodlights for all necessary illumination for working at night shall also be provided.

Electrical/MCC room shall be fabricated of sheet steel with suitable floor matting.  The room shall be dust tight and air conditioned. Fireproof insulation shall be provided under the roof of MCC room.  Further, the door shall be provided with hydraulic door closer.

Adequate number of impact idlers shall be provided integral with stacker-cum-reclaimer at the region where the bottom conveyor feeds material through transfer chutes onto the yard conveyor for the protection of the yard conveyor.

Suitable arrangement shall be provided at the starting point (belt take off point) of the tripper to avoid folding of belt while the tripper is in tension.

                        Brakes shall be provided for decelerating driven equipment/conveyor as per requirement.

Rail clamps shall be provided for various mobile machines travelling on rails as specified for those machines.

The necessary Electro Hydraulic Thrustor (AC) brakes, totally enclosed and fail safe, shall be provided as required for various equipment’s. Braking torque shall be adjustable from 0 to 100% of rated braking torque.  The brake shall be actuated by compression springs. The spring shall apply braking force directly to the shoe without using lever arm linkages.

Rail Clamp shall be designed for holding the machine stationary. Rating of the rail clamp shall be subject to the approval of Engineer.

Rail Clamp shall be actuated by compression springs, the spring shall apply the clamping force directly on the Rail clamp mechanism without using lever arm linkages once power supply is cut-off.  The force transmission mechanism from spring to rail clamp faces shall be very simple with minimum linkages.

The electro hydraulic thrustor shall be fitted with the brake. Limit switches shall be provided for brake applied/released positions.  The windings shall be provided with class-B insulation suitable for 415V  ± 10% at 50 Hz  ± 5% and combined variation of  ± 10%. Brake lining shall be asbestos with inter woven brass wires capable of withstanding 200°C temperature.

            The lining shall be fixed to the shoe by counter sunk screws.

Electro Hydraulic thrustor shall be fitted directly above spring without any intermediate linkage mechanism.

Rail clamp shall be provided between the two travel wheels. Further, limit switches shall be provided for Rail clamp ‘ENGAGED’ and ‘DISENGAGED’ signals.

Minimum clearance between the Rail clamp face and rail surface shall be 50mm.  However, this clearance may not be uniform for both the faces of Rail clamp throughout the length of rails.  Rail clamp shall operate satisfactorily under this condition without the need for any adjustments.

Complete Rail Clamp mechanism shall be manufactured from forged steel.

1.6.15               Monorails and Hoists

                        Suitable handling arrangements shall be provided for all equipment’s to transfer the equipment to maintenance area within the building and/or to transfer the equipment outside the building upto ground level for further transportation.  For this purpose Bidder shall provide monorails and hoist blocks with cross travel facility.

For the Hoists with more than 3.0 tonne lifting capacity or more than 10.0 M lift, motor operated hoist blocks for both long travel and lift shall be provided. Other hoist blocks shall be of hand operated type for both travel and lift.  However, all monorails coming out of the building shall be provided with electric hoist blocks, irrespective of load and lift. Adequate length of Cantilever shall be provided in monorails to lower the equipment to ground level clearing the building sidewalls.

The center line of monorail shall not deviate by more than 500 mm from the center of gravity of any equipment that is to be lifted.  Bidder shall take clear note of the fact that the number and monorail hoisting systems shall also be decided considering the movement of the equipment being lifted over/by the side of other equipment’s without removing the later.  The necessary levels of floors in various buildings shall be decided considering the above requirement.

Monorails shall be extended outside the building to handle the equipment to ground level. Suitable machinery well/ hatch and removable handrailing/ grating shall be provided on various floors of buildings, as necessary.

Electrically operated monogirder type hoists shall consist of following major components.

(a)              Electrically operated trolley complete with drive motor (Trolley travel speed maximum 15 m/min.).

(b)             Hoist cable, hoisting block and hooks complete with drive motor (Hoisting speed maximum 6m/min.).

(c)              Limit switch to prevent overhoisting, over lowering and over travel.

(d)        Festoon arrangement of feeding power to trolley assembly.

(e)        Erection hardware.

(f)        Pendent control station suspended from hoist.

The hoist shall be designed and constructed in accordance with the latest revision of IS:3938 and shall be suitable  for duty class 2.

Trolley movement and hoisting shall be effected by using two separate motors.  However the motors shall be suitable for 150 starts per hour at 40% CDF.

Trolley shall be designed to accommodate a wide range of I beams and shall be capable of travelling on straight as well as curved monorails with the design being such to maintain uniform distribution of pressure on the flanges.

Motor operated geared trolley shall have two (2) pairs of wheels, one pair of which shall be driven through motor.

Wire rope shall be of pre-formed type, hemp cored, regular lay 6/37 construction with a breaking strength of 160-175 kgf/mm2.  Reverse bend of ropes is not acceptable.  Minimum number of falls of rope shall be four (4).

All gears and pinions shall be of hardened and tempered steel with machine cut teeth in metric modules.  Surface hardening of steel is not acceptable.

All running shafts and wheels shall be fitted with roller bearings with a rated life not less than 20 years based on equivalent running time as per IS:3938.

An electromechanical brake shall provide restraining torque.  Brake lining shall be of asbestos.

                        Cast iron parts, wherever used, shall be of minimum grade 30, IS:210.

All hand operated chain pulley blocks shall be designed to IS:3832, the operating hand chain shall conform to IS:2429(1) grade 30 pitched and polished and the load chain to IS:3109 grade 40.  The chain pulley block shall be suitable for duty class 2. Hooks shall be of high tensile steel and heat treated as per Clause 7.1 (b) IS:3815.

All hoists/chain pulley blocks shall be selected to have minimum headroom and shall be selected to lift heaviest piece of equipment.  Further, it shall be possible to handle any equipment without disturbing other equipment.

The hand chain wheels shall be of cast steel, the wheels shall be with flanges and designed to ensure effective operation of hand chain. Further, suitable local brake shall be provided as per IS:3832 to arrest and sustain loads in all working positions.

The velocity rates, effort on chain required to raise the safe working load and travel and speed shall be within the limit specified in IS:3832.  Proof load test shall be carried out as per IS:3832.

The hoist mechanism shall consist of a grooved rope drum driven by electric motor through gears. Each end of the rope shall be anchored to the drum in such a way as the anchorage is readily available for maintenance. Each rope shall have not more than two (2) full turns of the drum when the hook is at its lowest position and one (1) spare groove when the hook is at its highest position.  The leading rope taken by the drum should not slope sideways when slack and it should not be caught between the gear wheel.

Rope drum, gear box, block etc. should be fabricated out of weldable quality steel.

Trolley wheels shall be of single flange type in the taper treads.  The wheels shall be mounted on antifriction bearings and shall be easily removable for repair/replacement.

The load hook shall be swiveling type forged circular shank section and shall confirm to IS:3815.

All gears and bearings shall be lubricated by grease.  All lubricating points shall be grouped together in easily accessible position.

The bottom block shall be of enclosed type and shall have guard against rope jamming in normal use.  It shall have standard forged swivel shank hook fitted on antifriction thrust bearing.  Lock to prevent hook from rotation and locking arrangement to prevent accidental unlocking shall be provided.  Pulley of the bottom block shall be provided with antifriction bearings.

All parts requiring replacement/inspection/lubrication shall be accessible without need for dismantling of other parts/structures.

All components of hoists of identical capacity and duty shall be interchangeable.

Hoists shall have permanent inscription on each side readily recognizable from floor level stating safe working load.

Pendant shall be provided with up/down/forward/reverse travel push buttons and indicating lamps.  Its power supply shall be limited to 24V AC.

The control panel shall be wall mounted type & easily approachable from the floor by a standing man.

For Inspection / maintenance of hoist components a fixed platform with ladder shall be provided for each hoist.

1.6.16               Dust Control System

The dust control system is required for control of fugitive dust emissions from dust generation points such as transfer points, feeders, crushers etc. Dust control is achieved by dust suppression system.

Bidder shall provide adequately sized fool proof dust control systems the performance of which should be guaranteed by the Bidder. 

1.6.16.1                        Dust Suppression System

Dust Suppression system complete with water supply system,  valves, piping, spray heads, pumps, drive motors with canopy, couplings with enclosure electricals, including supporting structures, approach/maintenance platforms, handling for equipment, civil & structural works, necessary accessories shall be provided at all places.

At specified locations dust suppression system shall be provided which comprises spray equipment discharging water in a fine mist, to capture air borne dust particles and direct them into the main coal flow,  agglomerate dust in the main coal flow and prevent release of dust particles from the main coal flow.

Water shall be drawn from the water storage tank by 2×100% electric motor driven pumps, and delivered through a pipe network system to spray heads at the dust suppression zones.  Solenoid valves shall be provided for open/close control of solution line to each spray head.  Each spray head shall consist of minimum 4 nos. nozzles.  Spray heads shall be provided at coal loading, discharge and at skirt board zone.  Pressure at inlet to spray head shall not be less than 3.5 Kg/cm²(g).

Trolley mounted pumping arrangement shall be provided for supplying water to the mobile paddle feeders.  In this arrangement, tank, supply pump(s) and spray nozzle header shall be mounted on paddle feeder trolley. The tank on P/F trolley shall be filled through flexible hose tapings on a ring header, which will remain, flooded through a connection to on ground storage tank.  This storage tank shall have make up connection from the common dust suppression system.

Each spray head shall have a provision for installing a pressure gauge whenever required.  Further, pressure gauges shall be provided at least at two locations.

At specified locations dust suppression system shall be provided which comprises spray nozzles discharging plain water in a fine spray to capture air borne dust particles and direct them into the main coal flow.  Water shall be discharged via a pipe work system through spray heads at the dust suppression zones.

1.6.16.2                        Track Hopper Dust Suppression System

Water shall be drawn from the water storage tank by electric motor driven pumps and discharged via a pipe work system through spray heads.  The dust suppression system shall consist of headers with spray nozzles routed along the entire length of track hopper on each side.  Each nozzle header shall be provided with adequate number of spray nozzles spaced at 1000 mm interval in zig zag way. Further, at the track hopper the water spray shall be of fogging type with a minimum pressure of 2.5 kg/cm2(g) at spray nozzle inlet.

1.6.16.3                        Coal Yard Dust Suppression System

Water shall be drawn from the water storage tank by electric motor driven pumps and discharged via a pipe work system through spray heads.  Spray heads shall comprise of swiveling type spray units spaced at an interval of approximately 30 meters around each coal pile.  Manually operated globe valve shall be provided to control water supply to each spray unit.  One no. pump shall be provided for each individual stock pile with common header.  Pressure at inlet to spray unit shall not be less than 4.5 kg/cm²(g).

1.6.17               Sump Pumps

Sump pumps alongwith level switches & piping upto nearest Purchaser’s drain (max upto 50.0 mtrs. from outside the building) shall be provided at all locations wherever natural drainage is not possible.  Further sump pumps alongwith drain pits shall be provided at other locations also, if required, during detailed engineering stage.

The capacity of each pump shall not be less than 50 M³/hr.  Minimum 10% margin on capacity and 20% margin on computed head shall be considered for selection of pumps.

Size of the sump pit shall not be less than 2.0 meters x 2.0 meters x 2.5 meters.  One no. of settling pit shall also be provided before sump pit so that water without heavy coal particles goes into sump pump pit.  High and low level switches shall be provided in the sump pump pit.

2×100% sump pumps alongwith level switches and piping up to nearest Owner’s drain (max. up to 50.0 meters from outside the building) shall be provided at all locations wherever natural drainage is not possible. Sump pumps along with drain pits shall be provided at other locations also, if required, during detailed engineering stage.

1.6.18               Service Water System

Service water distribution system complete with water supply system, valves, quick couplings, hose pipes with nozzle, piping, pumps, drive motors with canopy, couplings with enclosure, electricals, including supporting structures, handling for equipment’s, civil and structural works and necessary accessories shall be provided throughout the coal handling plant area in Bidder’s scope.

1.6.18.1                        Pipings, Fittings, Valves and Specialities

-           The material to be supplied for completing the pipe work shall include but not be limited to Straight piping, bends, tees, elbows, branches, laterals, crosses, reducing unions, couplings, caps, blank flanges, saddles etc. necessary for making reliable piping system.

-           Gaskets, ring joints, jointing material etc. as required.

-           Instrument tapping connections, stubs.

-           Gate, globe and check valves to start/stop, regulate and to

 prevent back flow.

-           Duplex Strainers

-           Anchors, hangers and supports as required including secondary steel embedments etc.

-           Bolts, nuts, fasteners as required for interconnection piping, valves and fittings as well as for terminal points.

-           Underground pipe protection for all underground pipe work.

-           Painting, anti-corrosive coatings etc. inside and outside pipes as necessary.

-           Welding electrodes and welding rods.

1.6.18.2                        Service Water System

Service water connections are to be provided in conveyor galleries and tunnels at 50 meter intervals.  Adequate number of these connections shall be provided in all transfer houses with minimum one no. at each floor and with minimum two (2) nos. at each floor in crusher house.  Each connection shall be provided with one (1) no. 32 NB globe valve and quick coupling.  One (1) No. Hose pipe with nozzle shall be provided in each building.

Service water distribution system shall be designed considering the water scheme and water requirement.

1.6.18.3                        Water Supply Pumps

                        Water supply pumps shall be provided as required.

The pumps shall be complete with drive motors, base plate and other accessories.  The constructional features of the pump shall be as follows:

(a)              Pump casing may be axially or radially split.  The casing shall be of robust construction. Casing drain and vent connections shall be provided.

(b)             Impeller shall be made in one piece and securely keyed to the shaft.  Locking device shall be provided to prevent its loosening during all conditions of operation.

(c)              Wearing rings shall be of renewable type.  Opposed wearing surface shall be of hardened material and shall have a hardness difference of at least 50 BHN.

(d)             Replaceable shaft sleeves shall be provided to protect the shaft where it passes through bearings and stuffing boxes.  The end of the shaft sleeve assembly shall extend through the packing gland.  Shaft sleeve shall be securely locked or keyed to the shaft to prevent loosening or rotation.  Shaft and shaft sleeves shall be machined and assembled for concentric rotation.

(e)              The design of the shaft shall take into consideration the critical speed, which shall be at least 20% away from operating speed.

(f)              Pump bearings shall be of antifriction type.  Bearings shall be readily accessible without disturbing the alignment of pump.

(g)              Packed stuffing boxes shall be of sufficient length to prevent leakage along the shaft and shall be complete with all packing and lantern rings required.

(h)             Pumps shall be furnished complete with flexible -coupling.

(i)               Couplings guards made of expanded metal and bolted to the base plate shall be furnished.

(j)               The common base plate for pumps and motor shall be in one piece and shall be made of fabricated steel.

(k)             Pump speed shall be less than 1500 rpm for pumps of capacity more than 10 m³/hr.

The power, head and flow characteristics of each pump shall be suitable for parallel operation.  The Power characteristics of the pumps shall be of non overloading type.

All rotating parts of the pumps shall be statically and dynamically balanced.

Design duty point of pump shall match with the average value of maximum and minimum flow rates of the pump in the stable operation zone.

                  Materials of construction of pump components shall be as follows:

1.6.19               Special Cleaning, Protection and Painting

                        Piping & Fittings

Surfaces to be painted shall be thoroughly cleaned of loose mill scale, rust etc. by wire brushing.

For overground exposed steel pipes, one shop and one site coat of red oxide zinc phosphate and two coats of synthetic enamel finishing paints unless specified otherwise shall be applied.  A minimum of 120 microns Dry Film Thickness (DFT) after finished coat of paint shall be ensured.

For steel buried pipeline, three (3) coats of heavy duty bitumastic paint shall be applied on the cleaned surface.  Finally, it should be wrapped with minimum 3 mm thick bitumen impregnated tar felt.  The lap joint of the felt shall be generally touched with heavy duty bituminous  paint.

1.6.20               Ventilation Systems

1.6.20.1                        General

The specification is intended to cover design, engineering, manufacture, supply, erection, testing and commissioning of the complete Ventilation & A.C. systems as specified hereinafter for the smooth and trouble free operation of CHP.

The Contractor shall refer to the other sections enclosed to appraise himself of the work and scope of supply of the other Contractors/Owners and shall coordinate his work with the work of other Contractors.

1.6.20.2                        General Description

The air quantity for mechanical ventilation system shall be estimated based on equipment and solar heat loads and the temperature rise inside the building. Necessary air filters shall be provided to supply only clean air into building.  Exhaust air shall be discharged at a suitable height above building.  Exhaust fans shall be provided for tripper floor.

The pressurised ventilation system having adequate nos. of supply air fans with washable metallic pre filters, HDPE fine filters, and exhaust fans with self closing flaps, ducting along with 3 phase AC motor drives, electricals, supporting structures, access / maintenance platforms shall be provided in all MCC/switchgear room areas of coal handling plant to be furnished under this specification. The pressurized ventilation system shall be designed considering 15 air changes to maintain these areas pressurised slightly above atmospheric pressure to prevent ingress of dust from outside.

Air conditioning system shall be furnished for control room area of main control room, MCC room on S/R and operator’s cabin and PLC rooms for Coal sampling units.  It shall be designed considering the equipment heat loads, solar heat loads, heat gain into the room, adequate no. of air changes etc. to maintain a uniform temperature and relative humidity within the air conditioned areas.  Outside design condition shall be as specified in Data Sheet of this section. PLC room having the PLC of coal sampling units near the CSU shall also be air-conditioned.

The ventilation system generally consisting of adequate number of supply air filters, ducting along with 3 phase AC motor drives, electricals, supporting structures, approach/maintenance platforms, civil and structural works and necessary accessories shall be furnished for ventilating the track hopper, underground portion of transfer points, underground conveyor tunnels and pent houses. Exhaust fans shall be provided for tripper floor.

            For design purpose the outdoor ambient temperature shall be taken as

50oC.

The ventilation system generally consisting of adequate number of supply and exhaust fans, metallic pre filters, HDPE fine filters, ducting along with 3 phase AC motor drives, electricals, supporting structures, approach / maintenance platforms, necessary shed, civil & structural works and necessary accessories shall be furnished for all MCC/switchgear rooms.

For design purpose the outdoor ambient temperature shall be taken as 50oC.

2×100% capacity air conditioning packaged units (PAC) with roof mounted air cooled condensers shall be provided for control room area of main control room.

One (1) no. window AC each for MCC room of S/R, operator’s cabin and PLC room for coal sampling unit shall also be provided.

Supply and return air distribution ducting complete with insulation, of resin bonded mineral wool equivalent of density at least 24 Kg/m³ and thermal conductivity of max. 0.49 mw/cm°C conforming to IS:8183 including supporting structures, approach/maintenance platforms, civil and structural works and necessary accessories shall be provided.

The design, manufacture, inspection and testing of Systems equipments shall comply with all the currently applicable statutes, regulations and safety codes in the locality where the equipment is to be installed.  The equipments  shall conform to the latest edition of the following standards and codes. Other internationally acceptable standards/codes, which ensure equal or higher performance than those specified, shall also be accepted.  Nothing in this specification shall be construed to relieve the contractor of the required statutory responsibility.  In case of any conflict in the standard and this specification, the decision of the Project Manager shall be final and binding.

            American Iron & Steel Institute (AISI)

            American Society for Mech. Engineers (ASME)

            American Society for Testing & Materials (ASTM)

            American Wire Gauge (AWG)

            Institute of Electrical & Electronic Engrs. (IEEE)

            Instrument society of America (ISA)

            National Electrical Code (NEC)

            National Electrical Manufacturers Association (NEMA)

            United States of America standards (USAS)

            Bureau of Indian Standards (BIS)

            Conveyor Equipment Manufacturers Association (CEMA)

IS:778               Gun Metal gate, globe & check valves for general purpose.

IS:780               Sluice valves for water works purposes (50 to 300 mm)

IS:1239 Mild Steel tubes & fittings.

IS:2379 Colour for the identification of pipe line.

IS:2906 Sluice valves for water work purposes.

IS:3589 Electrically welded steel pipes for water, gas & sewage

(200 to 2000 mm)

IS:5312 Swing check type reflux (non return) valves.

IS:1520 Horizontal centrifugal pump for clean, cold fresh water.

IS:5120 Centrifugal pump for clean, cold & fresh water.

ANSI B 31.1     Code for pressure piping.

Hydraulic institute Standards of U.S.A.

ASTM-D-2234              Standard Methods for collection of a Gross Sample of Coal.

ASTM-D-2013              Standard Method of Preparing Coal Samples for Analysis.

IS:3938 Specification for Electric Wire Rope Hoist

IS:3832 Hand operated chain pulley blocks

IS:2429 Round steel short link chain

IS:3109 Short link chain grade M(4)

IS:3815             Points hooks with shank for general engineering purposes

IS:210               Cast Iron Castings

IS:4682 Code of practice for lining of vessels and equipment

 for chemical processes.

IS:226               Structural Steel (Standard Quality)

IS:11592           Code of practice for selection and design of Belt

Conveyors.

            IS:3823 Dimensions for vibrating conveyors and feeders

with rectangular or trapezoidal trough.

IS:3688 Dimensions for shaft ends

IS:3681 General plan for spur & helical gears

IS:7403 Code of practice for selection of standard worm

and helical gear boxes

NEMA

            NEC                 For electronic circuit enclosures.

                        IS:11547           Electronic weighing in motion system.

                        IS:3588 Specification for electrical axial flow fans.

IS:2312 Propeller type AC Ventilation fans

IS:3963 Specification for roof-extractor units

IS:4894 Centrifugal Fans

IS:655               Specification for Metal Air Duct

ARI:210            Standard for Unitary air conditioning equipment.

ARI:270            Standard for application, installation and servicing of

unitary equipment.

IS:8183 Specification for bonded mineral wool.

IS:661               Thermal insulation for cold surfaces.

IS:4671 Expanded polystyrene for thermal insulation purpose.

IS:8148 Packaged Air conditioners.

“Belt Conveyors for Bulk Materials” published by Conveyor Equipment Manufacturers’ Association.

IS:7155             Codes of Practice for Conveyor Safety.

IS:1891 (Part-I) General Purpose Belting

IS:8598             Idlers and Idler Sets for Belt Conveyors

IS:4009 (Part-II)            Conical Head Grease Nipples

IS:3531             Pulleys for Belt Conveyors.

IS:226                           Structural Steel (Standard Quality)

IS:4682             Codes of Practice for Lining of Vessels and

Equipment for Chemical Processes.

IS:11592                       Code of practice for selection and design of

Belt Conveyors.

                        CAN / CASA – M422 M87  : Canadian standard association.

The details of the checks/tests to be carried out in the various equipments are to be submitted by the Contractor for Owners approval.  However, some indicative checks on different items are given below which should necessarily form a part of the Quality Assurance Programme to be agreed with by the Owner.

            i)          Pumps

All materials should be of tested quality and test certificates to be provided.

Shaft forgings to be also subjected to ultrasonic testing and hardness checks.

            Impellers to be dynamically balanced.

All pumps to be performance tested as per Hydraulic Institute Standard/Indian Standard.  Performance test to include check for noise, vibration level and temperature rise.

            ii)         Valves & Specialties

                        Valves & specialties shall be tested as per relevant standards & codes.

                        Seat leakage & hydraulic test to be carried out as per relevant code.

            iii)        Pipes & Fittings

                        Pipes & fittings shall be tested as per relevant standards & codes.

            iv)        Ventilation and Air Conditioning

                        Fan

All materials should be of tested quality and test certificates should be provided.

            Dynamic balancing of the fan impellers to be carried out.

Shop run test shall  be conducted on all centrifugal fans including check for noise and vibration level.

Performance test shall be conducted on one fan of each type at shop for capacity, pressure, efficiency and power consumption.

                        Valves and Specialties

                        Valves and Specialties shall be tested as per relevant code.