percent of deleterious substances. Grade aggregate from coarse to
fine. Compressive strength of solid concrete staves at 28 days
shall be 34.50 MPa 5,000 psi.
2.11.17
Bag Filter Vent
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NOTE: Consult the manufacturer of ash handling
equipment for venting requirements.
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Provide pulse jet bag filter vent for silo constructed of 10 gage steel
plate, fitted with rain hood. Bag material shall be sateen cotton capable
of withstanding not less than 91 degrees C 195 degrees F, weighing 0.33 kg
per square meter 9.75 ounces per square yard, having thread count of 4 by 2
per square mm 96 by 60 per square inch and permeability of 76 to 102 L/s
per square meter at 249 Pa 15 to 20 cfm per square foot at one inch water
column. Vent shall have not less than [_____] square meter feet effective
cloth filtering area, with each bag having a maximum effective cloth
filtering area of 0.56 square meter 6 square feet.
2.11.18
Rotary Ash Conditioner (Unloader)
Provide a complete dustless horizontal, floor mounted unloading device to
discharge ashes from silo to a [truck] [railroad car]. Unloader (ash
conditioner) shall include a 762 mm 30 inch diameter revolving drum which
rotates about fixed spray nozzles, and shall be complete with conditioner
and discharge compartments, scrapers, and other accessories as required.
Unloader drum shall be constructed of steel plate not less than 10 mm 3/8
inch thick and shall be roller chain driven by a totally enclosed, fan
cooled, [_____] volt, three phase, 60 Hz electric motor not less than 3.75
kW 5 hp as specified in paragraph entitled "Motors and Drives." Unloader
shall discharge conditioned ashes to a truck through a 6 mm 1/4 inch thick
steel plate chute. Unloader shall be designed to eliminate most dust in
unloading ash from the ash silo. Unloaders that utilize screws as a means
of mixing are not acceptable. Dustless unloader shall add water to ash,
but not to the extent that there is free or surplus water running or
dripping from the ash after discharge. Discharge ash shall be in a
semi-fluid, loose, free flowing condition.
2.11.19
Fluidizing System
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NOTE: Delete fluidizing system if not necessary.
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Provide a fluidizing system on the silo floor to ensure a constant and
uniform feed of ash through silo discharge outlet. System shall consist of
a series of diffuser modules, a conical diffuser hood, designed to support
the total weight of ash when the silo is full, and compressed air piping.
Each diffuser module shall be mounted on the silo floor using sloped
concrete pads. System shall operate from plant air system. Provide
pressure reducing valves, safety valves, and controls for a complete system.
2.11.20
Control Panel and Controls
Provide a semi-automatic control system for the ash handling system [as
indicated].
SECTION 15501N
Page 105
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