2.29.5
Vibrating Conveyor
Vibrating conveyor shall be the electric-motor driven mechanical vibrating
type with a capacity of [_____] metric tons/hour tons/hour when handling
coal weighing approximately 800 kg/cubic meter 50 pcf and with maximum lump
size of [_____] mm inches in diameter. Conveyor shall have a conveying
length as shown. The conveyor trough shall be fabricated of [_____] mm
gauge steel, [_____] mm inches in width and [_____] mm inches deep [and
provided with dust-tight cover]. Conveyor pans of 9.5 mm 3/8 inch thick,
Type 304L solid stainless steel plate shall be provided. The trough shall
be mounted on vibrator bars, torsion bars, or coil springs attached to
yoker legs of rigid cross brace construction and fabricated of
corrosion-resistant material with hardened steel encased rubber bushings at
articulation points. The base shall be fabricated of steel channels or
angles bolted directly to [building support] [concrete foundations]. The
drive shall be through an eccentric shaft supported by a double row of
self-aligning ball-or roller-bearing pillow blocks. Positive action motion
shall be imparted to the trough by a cast steel connecting rod attached to
the trough by rubber-bushed wristpin and securely locked by taper lock
bushings. The conveyor shall be driven by a [totally enclosed,
nonventilated type] [totally enclosed, fan-cooled type suitable for
installation in Class II, Division 1, Group F hazardous location in
accordance with NFPA 70] electric motor connected to the eccentric shaft by
V-belt drive. [The motor starter shall be [manual] [[magnetic]
[across-the-line] [reduced voltage start]] type with [general-purpose]
[weather-resistant] [water-tight] [dust-tight] [explosion-proof] enclosure.]
2.29.6
Gravimetric Weigh Feeder
The weigh feeder shall be a metering belt type device designed to operate
at a variable rate ranging from 10 percent of maximum capacity to [_____]
metric tons/hour tons/hour. Flow rate shall be automatic. A
silicon-controlled, rectifier dc drive shall automatically adjust the belt
speed to maintain the rate of material flow, as set on the controller. The
weigh feeders shall meet or exceed the requirements of NIST HB 44
[Southern] [Eastern] [Western] Weighing and Inspection Bureau. They shall
have an accuracy of 1/2 of 1 percent of flow rates over their total
variable rated capacity. The feeder shall be provided with a flexible boot
for connecting the gate to the feeder inlet chute, which in turn shall be
flared to produce a feed opening tapering from [_____] wide to [_____] wide
with the direction of flow of material. The belts for feeders shall meet
RMA IP-1 requirements, conforming to the Conveyor and Elevator Belt
Handbook, fire-resistant type conforming to the standards of Part 18.65, of
the 30 CFR 1. Top belt cover thickness shall be 6.4 mm 1/4 inch with
bottom cover 3.2 mm 1/8 inch thick. Belt edges shall have minimum 25 mm 1
inch flanges and shall be sealed by carrying the cover around the carcass
edges during manufacture. Cover and skim coat material shall be comparable
to those meeting the requirements of the RMA IP-1 for impact and abrasion
resistance. The weight sensor shall be a heavy-duty, industrial,
electronic force transducer flexure-mounted to the force collection system.
Each sensor shall have a remote indicating meter and a six-digit
totalizing counter located, installed, and connected in the boiler control
panel. Unit frame shall provide rigid support for the material load, belt,
and idlers. The unit shall be shop assembled complete with drive and all
appurtenances, and shall be dust-tight in operation.
SECTION 15559A
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