flanges shall be standard drilled pipe flange. Rotor blades and sealing
arrangement shall be manufacturer's standard for the intended service. When
rotors are equipped with adjustable tips, provide a service door in body of
valve for tip adjustment. Provide packing gland type shaft seals with
suitable packing materials. Shaft bearings shall be outboard sealed ball
bearings. Periphery seals shall be such that a complete seal is
accomplished at a differential of [_____] Pa inches of water
static/pressure.
2.12.5
Conveyors
2.12.5.1
Chain Drag Conveyor
Provide with endless chain for dragging coal ashes from front of boilers
along a recessed trough to the inlet chute of a bucket elevator. Conveyor
shall have [_____] meter feet sprocket centers, operate at speed not
greater than 35 mm/sec 7 fpm, and have a capacity of not less than [_____]
Mg tons per hour of 640 kg per cubic meter 40 pounds per cubic foot ash.
Provide conveyor complete with continuous chain, drive, and take up
terminals, gears, shafts, bearings, return rolls, hard white iron trough,
ash intake gratings, floor plates, discharge chute, electric motor,
reduction gear, and supports. [Chain drag conveyor shall be designed for
future length of [_____] meters feet.]
a.
Head and Foot Shafts: Provide SAE-1045, steel head and foot
shafts not less than [_____ and _____] mm [_____ and _____] inches
in diameter, respectively, mounted in anti-friction roller
bearings in pillow blocks. Foot shaft shall have screw-type
takeups with not less than [_____] mm inches adjustment.
b.
Terminal Sprockets: Gray iron chilled rim not less than [_____] mm
inches in diameter with solid web and not less than eight teeth
each.
c.
Chain: Combination drag type of riveted construction. Design
chain symmetrically so that it can be turned over after one side
is worn. Chain shall be [_____] mm inches wide with a pitch not
greater than 200 mm 8 inches and an ultimate strength of not less
than [187] [249] kN [42,000] [56,000] pounds. Construct chain of
promal, a pearlitic malleable iron, center links not less than
[_____] mm inches high, and heavy [_____] mm inch thick heat
treated carbon steel side bars. Steel pins shall be cold rolled
steel not less than [_____] mm inch in diameter, press-fitted into
sidebars, and machined flat on one side to prevent rotation.
Center section shall be rugged block type forming a rigid
rectangle for maximum resistance to distortion with broad wearing
shoes contoured to prevent snagging and damage to chain or trough.
Barrels of center section shall be chambered to provide lubricant
reservoir and still provide maximum bearing area for pins. Shape
barrel with pushing surface on one side and for contact with
sprocket on the other side.
d.
Trough: Concrete lined with not less than [_____] mm inch thick
hard white iron approximately as indicated. Trough shall be
[_____] mm inches wide with hinged 6 mm 1/4 inch thick checkered
steel plate covers. Covers shall be installed to be dusttight.
Coordinate concrete work with conveyor manufacturer's requirements.
e.
Return Rollers:
Chilled rim, single flange, enclosed-oiling type
SECTION 15501N
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