the sidewall header and the frame. Provide restraints in the
boiler setting to prevent seals at rear of stoker from opening up.
j.
Stoker Support: Stoker and drive shall be complete with
supporting structural steel framework. Locate and protect
structural supports so that they will not be overheated or damaged
by heat from either the furnace or ash pit.
k.
Grate Return Run Support: Adequately support the lower return run
of the grate on a system of cross members and longitudinal members
or skids. Provide an air seal between this lower drag frame and
ash pit and siftings hopper.
2.4.1.3
Grate Ash Discharge Enclosure
Enclose rear end of grate, where ash is discharged into the hopper below
the floor line, with a dust tight enclosure made of heavy steel plates
properly protected with fire brick where exposed to the furnace. Fit
vertical ends of this enclosure with cast iron, refractory lined inspection
and access doors, one for each feeder. Seal off roof of this enclosure
with refractory, protecting metal parts from the furnace temperature with
refractory. Exposed metal parts in the enclosure are not acceptable.
Enclosure shall be compatible with the ash storage hopper as specified
under paragraph entitled "Ash Handling System" this section.
2.4.1.4
Stoker Grate Drive
Drive the grate of the stoker through hydraulic drive, or with electrical
motor and transmission equipment as specified below. Drive shall have a
variable speed ratio of not less than six to one with the speed changing
device, controlled automatically by the combustion control system. Provide
a manual and reversing adjustment so the grate speed can be operated
independent of the combustion control system. Provide adequate safety
release to prevent damage to the drive or grates due to foreign material or
jamming of the grates. Provide the front and rear shafts of the grates
with an adequate lubrication system with fittings located on the outside of
the setting.
a.
Electric Motor: Motor shall be [_____] volt, [_____] phase,
[_____] rpm, 60 Hz, totally enclosed, fan cooled, not less than
[_____] kW hp as specified under paragraph entitled "Motors and
Drives" in this section.
b.
Mechanical Drive: Mechanical drive shall include variable speed
transmission with gears and chains, enclosed in an oil tight case,
and running in a bath of oil. Bearings shall be of the
anti-friction type, with hardened inner and outer races and fitted
with forced lubrication fittings.
c.
Hydraulic Drive: Hydraulic drive shall include a complete
hydraulic system with adequately sized reservoir, dual pumps, oil
piping to and from drive, control and isolating valves, oil
cooler, when required, with self-operated cooling water control
valve, oil temperature indicator, and other accessories for a
complete, satisfactory operating system.
2.4.1.5
Miscellaneous Equipment
Provide shafting, couplings, bearings, drives with guards, linkages, rods,
SECTION 15502N
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