roller-chain-connected to the drive shaft. Motor shall be [totally
enclosed, nonventilated type] [totally enclosed, fan-cooled type] [totally
enclosed, fan-cooled] type suitable for installation in a Class II,
Division 1, Group F Hazardous location in accordance with NFPA 70. [Motor
starter shall be [manual] [[magnetic] [across-the-line] [reduced voltage
start]] type with [general-purpose] [weather-resistant] [water-tight]
[dust-tight] [explosion-proof] enclosure.] Conveyor frame shall be
constructed essentially as indicated, with supports and additional bracing
as required for rigidity.
2.24
ASH HANDLING SYSTEM
2.24.1
Boiler Room Ash Handling System
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NOTE: When specifying boilers with capacity of 4.1
MW (14 million Btuh) or less per boiler, paragraph
Ash Hopper and subsequent paragraphs will be
deleted, except applicable portions of paragraph Ash
Silo through paragraph Rotary, Dustless Unloader
will be retained.
**************************************************************************
The ash handling system shall be the dry pneumatic type in stoker fired
boilers. This system shall gather ash from the boiler forward ash
discharge grate hopper and from [economizer] [air preheater] ash discharge
hopper and other filtration systems and shall discharge to the ash storage
silo located outside of the building. The entire system shall be
coordinated to fit the equipment supplied. Ash dust control conditioners
shall be used to reduce fugitive dust emissions during discharge of ash
from the storage silo.
2.24.1.1
Ash Hopper
Ash removal hopper for each boiler shall be constructed of 6.4 mm 1/4 inch
thick steel plate, minimum, with suitable external structural steel
supports for connection to boiler ash hopper and necessary internal anchors
for holding refractory lining in place. Refractory lining shall be 225 mm
9 inches thick on vertical walls and 150 mm 6 inches thick on feed plates.
Each hopper shall be furnished with a sliding ash gate. Each boiler
sliding gate unit shall be provided with an access compartment to allow
gathering and cooling of ash. A cast-iron grate shall be provided along
with a manually-operated air-tight inlet valve for feeding ash into the
pneumatic gathering line. A hinged, steel access gate shall be provided at
each compartment. Spring loaded air intakes shall be provided at the end
of each header. The structural integrity of the hopper shall be based on
the ash weight of 1120 kg/cubic m 70 pcf.
2.24.1.2
Clinker Grinder
**************************************************************************
NOTE: Delete this paragraph if coal analysis
indicates no possibility of slag formation.
**************************************************************************
Clinker grinder unit shall be provided with [_____] mm inch wide double
roll for each hopper outlet gate housing. The grinders shall have
manganese steel rolls and cast-iron housings with grinder shafts mounted on
outboard bearings protected by a stuffing box and gland assembly. Grinder
SECTION 15555A
Page 78
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