NATIONAL ALUMINIUM COMPANY LIMITED - Rites

14.2.13 Cast iron parts, wherever used, shall be of minimum grade 30, IS:210.
14.2.14All chain n pulley blocks shall be designed to IS:3832, the operating hand chain shall conform to
IS:2429 grade 30 pitched and polished and the load chain to IS:6216 grade 80. The chain
pulley block shall be suitable for duty class 2. Hooks shall be as per IS: 8610 & with
antifriction bearing for bottom look.
14.2.15 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 disturb disturbing other equipment.
14.2.16 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 load loads in all working positions.
14.2.17 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. Balance requirements shall be as discussed in earlier clauses pertaining to electric
hoists.
14.2.18 Hoist for Gravity Take up arrangement and bend pulley.
For handling bend pulley, take take-up up pulley and counter weights following hoisting
arrangement shall be provided:
(1) For handling bend pulleys, hooks of adequate capacity shall be provided at the top of gallery.
Further minimum four (4) nos. manually operated chain pulley blocks of adequate capacity
shall also be provided for the entire coal handling plant for handling bend pulleys.
(2) For handling take-up up pulleys, manual hoist along with mono rail beam of adequate capacity
having cross travel, arrangement shall be provided at bottom of gallery to handle take take-up
pulley only of conveyors.
(3) For handling take-up up weight, a separate mmanual
anual hoist with mono rail beam of adequate
capacity shall be provided to hold complete counter weight (inclusive of all counter weight
blocks). This hoist shall be provided for holding the counter weight and shall be located in
the zone of counter weight travel.
14.3 CONSTRUCTION REQUIREMENT
14.3.1 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 mai maintenance. ntenance. 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 nd it should not be caught between the gear wheel.
14.3.2 Rope drum, gear box, block etc. should be fabricated out of weldable quality steel.
Technical Specification:Sec-4,System System Parameters, Operation & Control Philosophy
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