complete mechanical ash handling system. Provide related electrical work
required to operate the ash handling system.
2.11.1.2
Routing
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.
2.11.1.3
Discharge
Discharge ash into ash storage silo in a dry condition. Arrange silo
equipment for disposal of conditioned ash to trucks. Operation shall be as
dustless as possible.
2.11.1.4
Maximum Noise Level
Noise level of the operation shall not exceed 85 decibels sound pressure
level 1.52 meters 5 feet from the equipment in any direction.
2.11.2
System Valving
2.11.2.1
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 Brinnell hardness of 500. Valves
requiring part of the housing to form an airlock seal are not acceptable.
a.
Electric Motor: Totally enclosed, fan cooled, [_____] volt,
[_____] phase, 60 Hz not less than [_____] kW hp as specified
under paragraph entitled "Motors and Drives" in this section.
2.11.2.2
Manual Valve Intakes for Bottom Ash
Provide in front of the 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.
2.11.2.3
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
flanges shall be standard drilled pipe flange. Rotor blades and sealing
arrangement shall be the manufacturer's standard for the intended service.
When rotors are equipped with adjustable tips, provide a service door in
the body of the valve for tip adjustment. Shaft seals shall be of the
packing gland type 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.
SECTION 15502N
Page 121
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