and mount in antifriction roller bearings. Mount head shaft in fixed
pillow blocks and foot shaft shall have screw-type takeups with not less
than [_____] mm inches adjustment.
2.9.8.2
Terminal Sprockets
Cast iron terminal sprockets with chilled rims not less than 380 mm 15
inches in diameter. Foot shaft sprockets shall be split type in two 180
degree sections to facilitate removal in shallow pit.
2.9.8.3
Chains and Flights
Chains shall be bar link type each having a pitch of not greater than 150 mm
6 inches and an ultimate strength of not less than 20,430 kg 45,000 pounds.
Construct chain of heat treated carbon steel components with not less than
a 22 by 38 mm 7/8 by 1 1/2 inch wide center link, 10 mm 3/8 inch wide by 38
mm 1 1/2 inch thick side bars, fastened with 18 mm 5/8 inch diameter pins.
Construct bar flights of 10 mm 3/8 inch thick steel bars not less than 50 mm
2 inches high with flight width of not less than [_____] mm inches.
Flight spacing shall be such that feeder shall move the required coal with
a head shaft speed not greater than [_____] rpm.
2.9.8.4
Frame and Enclosure
Construct feeder frame of structural steel properly tied and braced,
complete with guides and track for both the carrying and return runs, of
not less than 80 by 80 by 10 mm 3 by 3 by 3/8 inch steel angles with not
less than 6 mm 1/4 inch high renewable carbon steel wear bars. Enclosure
shall be dusttight of not less than 10 gage (3.42 mm0.1345 inch) commercial
hot rolled steel plate. Enclosure shall be removable in sections. Top and
side panels at head and foot sections shall be hinged and removable for
access to chain sprockets.
2.9.8.5
Trough
Construct trough with flat bottom of not less than 10 mm 3/8 inch thick
steel plate. Trough shall be removable and constructed with flanged
discharge opening.
2.9.8.6
Hopper
Construct hopper not less than 2 1/2 meters 8 feet long and 3 meters 10 feet
wide of structurally reinforced 10 mm 3/8 inch thick steel plate lined
with 10 gage (3.42 mm0.1345 inch) 410 stainless steel plate. Hopper sides
shall not slope less than 55 degrees from the horizontal. Construct hopper
with a shield over the return run so that coal is fed directly to the
bottom conveying run.
2.9.8.7
Grating
Hopper grating shall have openings 90 by 90 mm 3 1/2 by 3 1/2 inches.
Construct grating of 65 by 10 mm 2 1/2 by 3/8 inch steel bars and 20 mm 3/4
inch diameter steel rods. Weld grating and make in sections for ease of
removal. Provide intermediate beams to support the grating.
2.9.8.8
Flight Feeder Drive
Flight feeder shall be driven by an electric motor direct connected by
means of flexible coupling to a reduction gear unit having alloy steel
SECTION 15502N
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