2.12.7.2
Fluid Gear Drive
Crushers shall be driven by a fluid gear drive including a totally
enclosed, fan cooled, [_____] volt, three phase, 60 Hz electric motor not
less than 3.75 kW5 hp, as specified under paragraph entitled "Motors and
Drives" in this section, fluid coupling and reduction gear, integrally
mounted in dust and oil tight enclosures. Fluid drive shall protect the
unit from excessive shock. Drive shall automatically reverse when stalled;
crusher shall reverse and move forward three times and, after the third
time, shall shut down and alarm when still stalled.
2.12.8
System Valving
2.12.8.1
Side Intake Valve for Fly Ash
Provide side intake valve for fly ash collection at each hopper, including
dust collection hoppers and rear pass hoppers, and other collection points.
Side intake valve shall be pneumatically opened, spring closed, totally
enclosed disc valve of cast iron construction with wearing surfaces of
Brinell hardness not less than 350. Provide valve complete with flanged
inlet hopper, handhole with gasketed cover and clamp and couplings. Side
intake valve shall feed ash to conveyor line on an angle, thus permitting
air to mingle with the ash in the proper proportion to eliminate clogging.
Valves shall provide positive and automatic air tight shutoff and dust
tight pickup. Valve shall close on failure of operating air and before the
discharge cycle of the intermittent conveyor operation. A full load
regulating switch shall control each valve to prevent overloading of the
2.12.8.2
Rotary Valve Intakes for Bottom Ash
Provide a rotary valve, designed for regulating bottom ash to the a
conveyor pipeline, under each crusher. Valve shall provide intake
isolation and prevent overfilling or plugging of the conveyor line.
Construction of valve shall be of cast iron with wearing surfaces of
Brinell hardness not less than 350. Valve shall be pneumatically operated.
2.12.8.3
Air Intake
Provide spring loaded, swing disc, check valve type air intake, designed
for air induction, at the end of each conveyor branch. When intake is
located exposed to the weather, provide a rain hood.
2.12.8.4
Isolating Valves (Line Valves)
Provide an air operated, totally enclosed rotary slide gate isolating valve
at each branch pipe line connection to prevent air flow through an unused
branch line. Construct valve of abrasion resistant metal, machined and
fitted to ensure a vacuum tight fit and guard against leakage and excessive
maintenance. Provide purge air connection and a solenoid valve in the
valve housing or cavity for purging the gate cavity of ash.
2.12.8.5
Silo Discharge Valve
Provide a rotary feeder for discharging bottom ash and fly ash from the ash
silo. Feeders shall be of ductile iron or cast steel and shall be complete
with motor, motor support, chain drive, and necessary guards. Chain shall
be driven through a torque limiting clutch on the driven sprocket equipped
with electric cutout switch and alarm. [Feeder shall have spring-loaded
SECTION 15502N
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