2.12.6
Bucket Elevator
Provide a dusttight bucket elevator centrifugal discharge type, having
approximately [_____] meters feet [_____] mm inch sprocket centers,
vertical chain and bucket, operating at a speed not to exceed [_____] m/s
fpm, and having a capacity of not less than [_____] Mg tons per hour of 640
kg per cubic meter 40 pounds per cubic foot ash. Provide bucket elevator
complete with continuous chain and attached buckets, sprockets, gears,
shafts, bearings, casing, top hood, discharge spout, bottom boot, access
doors, electric motor, reduction gear, service platform, and accessories.
2.12.6.1
Head and Foot Shafts
Not less than [_____ and _____] mm [_____ and _____] inches in diameter,
respectively. Construct shafts of cold rolled steel and mount in
antifriction roller bearings with forced lubricating type fittings. Mount
foot shaft in fixed pillow blocks. Head shaft shall have screw-type
takeups with not less than [_____] mm inches adjustment.
2.12.6.2
Terminal Sprockets
Cast iron with chilled rims. Head sprocket shall be not less than [_____]
mm inches in diameter and foot sprocket not less than [_____] mm inches in
diameter.
2.12.6.3
Buckets ands Chain
Construct buckets of malleable iron not less than 200 mm long, 127 mm wide,
and 140 mm deep 8 inches long, 5 inches wide, and 5 1/2 inches deep.
Buckets shall be mounted by not less than four bolt attachments to a single
strand of steel bushed chain having an ultimate strength of not less than
178 kN 40,000 pounds and pitch of 100 mm 4 inches. Bucket spacing shall
not be greater than 406 mm 16 inches.
2.12.6.4
Backstop
Differential band brake type to prevent reversal of chain and buckets in
case of power failure.
2.12.6.5
Elevator Casing
Not less than 298 by 991 mm 11 3/4 by 39 inch internal dimension and
constructed of not less than 5 mm 3/16 inch commercial hot rolled mild
steel plate with 50 by 50 by 6 mm 2 by 2 by 1/4 inch corner angles for full
height of elevator casing. Fabricate casing in standard sections from 3 to
3.66 meters 10 to 12 feet high with 50 by 50 by 6 mm 2 by 2 by 1/4 inch
angle flanges at the end of each section. Provide a hinged inspection door
not less than 610 by 762 mm 24 by 30 inches in the section immediately
above the boot section and where indicated. Casing and inspection doors
shall be of dusttight construction with flange angles continuously welded
and gasketed. No makeshift repairs or field patching to overcome leakage
shall be permitted. Coat casing interior with not less than 1.60 mm 1/16
inch thick coal tar primer and enamel conforming to SSPC PS 11.01.
2.12.6.6
Head Section
Construct of not less than 5 mm 3/16 inch commercial hot rolled mild steel
plate in heavy angle frame with split, hinged, and removable top cover hood
built of not less than 10 gage (3.42 mm0.1345 inch) commercial hot rolled
SECTION 15501N
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