2.11.3
Conveyors
2.11.3.1
Chain Drag Conveyor
Provide 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 [_____] meters feet sprocket centers, operate at speed not greater than
35 mm per second 7 feet per minute, and have a capacity of not less than
[_____] Mg per hour of 640 kg per cubic meter tons per hour of 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 [_____] meter feet.]
a.
Head and Foot Shafts: Provide SAE 1045, steel head and foot
shafts not less than [_____] and [_____] mm 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: Terminal sprockets shall be 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
on [_____] mm inch diameter carbon steel shafts spaced at not more
than 3 meters 10 feet apart.
f.
Discharge Chute: Construct of not less than 10 mm 3/8 inch steel
plate and slope at not less than 60 degrees.
g.
Electric Motor and Drive: Totally enclosed, fan cooled, high
torque, [_____] volt, [_____] phase, 60 Hz not less than [_____] kW
hp as specified under paragraph entitled "Motors and Drives" in
SECTION 15502N
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