2.12.6.1
Construction
Not less than 6 mm 1/4 inch thick, ASTM A 36/A 36M, steel plate, dust
tight, floor supported steel structure with refractory lining.
Provide
required steel columns, beams stiffeners and cross bracing. Bolt top
section of the hopper to the stoker support steel. Design load of hopper
shall be based on 1120 kg per cubic meter 70 pounds per cubic foot. Slope
sides at not less than 45 degrees from the horizontal to maintain positive
feed to the outlet.
2.12.6.2
Refractory Materials
As recommended by the manufacturer; the minimum total thickness of the
refractory and insulating block lining shall not be less than 178 mm 7
inches. Refractory shall be minimum of 114 mm 4 1/2 inches.
2.12.6.3
Provide each hopper with refractory lined, dust tight, water cooled,
vertical lift doors, of an opening size not less than 560 by 560 mm 22 by
22 inches. Each door shall be [air-cylinder operated] [chain wheel
operated]. [Provide intermediate positioning capability with air cylinder
operators.] Provide each door with guide rollers and support arms to ensure
smooth operation without binding. When doors are vertical the minimum
number of rollers shall be 4; for a sloping surface, the minimum number of
rollers shall be 6.
2.12.6.4
Hopper Lift Door Enclosure
Provide not less than 6 mm 1/4 inch thick steel, dust tight, enclosure, for
each vertical lift door. Match enclosure to housing of the clinker crusher
and make it large enough to enclose the outlet and the vertical lift door.
Provide hinged inspection and cleanout door on the front of the enclosure.
2.12.6.5
Hopper Access Door
Provide hinged access door on one side wall of each hopper. Door shall be
cast iron, air tight swing-away locking type with refractory lining.
Install door so that it is convenient and easy to use.
2.12.7
Clinker Crusher
Provide a clinker crusher mounted under each hopper discharge outlet, below
the vertical lift door enclosure, capable of reducing clinkers from bottom
ash to a maximum size of 50 mm 2 inches at a rate not less than the
conveyer system capacity.
2.12.7.1
Construction
Single roller crusher unit with extra heavy housing, outboard bearings
sealed against grit infiltration, motor and drive. Housing shall be 15 mm
1/2 inch thick. Crusher rollers shall have replaceable cam segments
(teeth) with a minimum Brinell hardness of 450. Each cam tooth shall be
designed to permit resurfacing with hard material. Stationary heavy cast
iron or manganese steel abrasion resistant wear plates, of a Brinell
hardness not less than 350, shall be mounted about the crusher rollers.
Cam shaft rotational speed shall not exceed 20 rpm.
SECTION 15502N
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