2.9.13
Coal Scales
Stationary, automatic, dust-proof, belt-fed, batch type with rated capacity
of not less than [_____] Mg tons per hour and a hopper capacity of 91 kg
200 pounds. Coal scales shall be complete units, including body, belt
feeder, feeder drive, bypass, weighing mechanism, weigh hopper, controls,
counters, and remaining items required to make a completely automatic coal
scale.
2.9.13.1
Body
Dusttight, of welded heavy steel plate construction with base angles not
less than 6 mm 1/4 inch thick. Top plate, bypass plate, and reducer
mounting plate shall be not less than 6 mm 1/4 inch thick, with other
plates of not less than 11 gage (3.04 mm0.1196 inch) steel plate. Provide
large, gasketed, dusttight doors with adjustable pre-set compression type
latches and forged steel hinges for inspection and maintenance purposes.
Door openings shall be sufficient to allow removal of feeder and hopper
without removal of screws or bolts.
2.9.13.2
Feeder
A self-contained unit with an endless belt which is capable of being
removed from one end or side. Construct feeder of heavy rigid steel frame
with an 11 gage (3.04 mm0.1196 inch) stainless steel plate to support the
belt on the carrying run. Head and takeup shafts shall be cold rolled
steel carried on self-aligning ball bearings equipped with dust seals and
fitted for pressure lubrications. Bearings shall be capable of being
lubricated during scale operation. Takeup shaft shall have screw-type
takeup bearings and pulleys shall be crown faced steel for proper belt
tracking.
2.9.13.3
Feed Belt
Channel type and of endless construction without splice. Belt shall be not
less than 7.94 mm 5/16 inch thick of three ply heavy fabric core
construction with chemical and abrasion resistant rubber coating. Feeder
skirts and leveling plate shall be stainless steel and shall be arranged to
provide a continuous stream of constant width and depth coal on the feed
belt.
2.9.13.4
Electric Motor And Drive
Totally enclosed [_____] volt, [_____] phase, 60 Hz, with heavy duty
reduction gear not less than 0.56 kW 3/4 hp as specified in paragraph
entitled "Motors and Drives." Scale shall be capable of bypassing coal
without disconnection of drive. Drive disconnection shall not be required
for feeder removal unless special provisions are made for a quick and
simple drive disconnection.
2.9.13.5
Coal Bypass
Provide a quick-operating coal bypass with an easily operable lever located
on the outside of scale body. Operating lever operation shall instantly
bypass coal around the feeder section and weighing mechanism without
release of belt tension to prevent entry of coal between belt and pulley or
support plates. Bypass construction shall not restrict inlet opening size
for normal scale operation.
SECTION 15501N
Page 85
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