additional wheeled covered dumpsters. For greater
ash removal rates screw conveyors could be used for
removing ash from the stoker ash pits. These could
convey ash to wheeled ash dumpsters or into a drag
conveyor, bucket elevator, ash silo system.
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Provide a complete integrated, mechanical, semi-automatic, ash handling
system with chain drag conveyor, screw conveyors, bucket elevator, material
intakes, rotary valves, [ash doors and enclosures,] silo vent filter, ash
silo, rotary ash conditioner, and other equipment that may be necessary for
a complete mechanical ash handling system. Provide related electrical work
required to operate the ash handling system.
2.12.1
Ash Silo
The system shall receive, and convey to the ash silo, ash from the stoker
fired boiler ash storage pits, [economizer hoppers,] [baghouse hoppers,]
and other pollution control equipment hoppers.
2.12.2
Ash
Discharge ash into the ash storage silo in a dry condition. Arrange silo
equipment for disposal of conditioned ash to trucks. Operation shall be as
dustless as possible.
2.12.3
Maximum Noise Level
Noise level of operation shall not exceed 85 decibels sound pressure level
1.50 meters 5 feet from the equipment in any direction.
2.12.4
System Valving
2.12.4.1
Rotary Valves
Provide rotary valve feeders of carbon steel construction complete with
drive, guard, motor mount and gaskets, carbon steel adjustable blade tips,
adjustable shoe type air seal and right angle gearhead drive motor. Rotor
blade tips and shoes shall have a minimum Brinell hardness of 500. Valves
requiring part of the housing to form an airlock seal are not acceptable.
The electric motor for the rotary valve feeders shall be totally enclosed,
fan cooled, [_____] volt, [_____] phase, 60 Hz., and not less than [_____]
kW hp, as specified in paragraph entitled "Motors and Drives."
2.12.4.2
Manual Valve Intakes for Bottom Ash
Provide in front of stoker ash pit doors, a 610 by 610 mm 24 by 24 inch
cast iron grid and hopper with opening approximately sized for the
conveyor. Provide intake with dusttight, removable 6 mm 1/4 inch thick
checkered steel plate cover.
2.12.4.3
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
hinged bypass plate to permit passage of clinkers.] Inlet and outlet
SECTION 15501N
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