Coal-Fired
Excess Volume
Excess Pressure
Oil-Fired
Forced Draft
10 percent
20 percent
2.6.1.2
Fan Construction
Fan shall be arrangement [_____] in accordance with AMCA 801. Fan shall
have backward inclined or backward curved single thickness blades.
Fan
shall have stable characteristics with self-limiting power curve.
Construct fan wheel of steel. Balance fan wheel both statically and
dynamically at factory. Provide fan with air cooled roller bearings
mounted in horizontally split pillow blocks. Fan housing shall be welded
constructed of a minimum of 12 gage steel. Provide flanged inlet and
outlet connections, 50 mm 2 inch plugged opening in low point of scroll and
hinged, quick opening access door in scroll. Provide a multi-blade vortex
ball bearing damper in fan inlet with an extended, ball bearing mounted
control lever for field connections to control actuator.
Interior of fan,
including wheel, shall be painted with two coats of red primer and one coat
of rust resistant enamel with a total dry film thickness of 0.152 mm 6 mils.
Exterior surface of the fan shall have two coats of red primer with a
total dry film thickness of 0.10 mm 4 mils. Cleaning and painting shall be
in accordance with the manufacturer's standards.
2.6.1.3
Fan Drive
Equip fans with [both] [a motor] [and] [steam turbine] drive. The [motor]
[and] [turbine] shall be direct connected to the fan [with a gear type
flexible coupling] [with a roller type, hardened steel clutch coupling
consisting of an over-running clutch and double flexing coupling to permit
instantaneous change-over from one drive to the other. One clutch coupling
shall be provided between the fan and each driver. Clutch couplings shall
be selected for the maximum torque requirement of the fan, with a 1.5
service factor. Provide a removable guard over each clutch coupling].
2.6.1.4
Electric Motor
Motor for driving the forced draft fan shall be [_____] volt, three phase,
60 Hz, [open drip-proof] [totally enclosed fan cooled] [two speed]
[variable speed] not less than [_____] kW hp, as specified under "Motors
and Drives" in this section, and shall not overload at the specified
capacity with unheated cold air. [Fan motor shall be suitable for
installation in a hazardous location as defined by NFPA 70.] Provide [_____]
mm inch thick steel soleplate for motor. Soleplate shall be common for
four motor mounting bolts. Separate parallel soleplate bars are not
acceptable.
2.6.1.5
Steam Turbine
Steam turbine shall drive the fan through a reduction gear shall be single
stage, rated at not less than [_____] kW hp, with inlet steam pressure of
[_____] kPa (gage) psig, [_____] degrees C F total temperature and a normal
exhaust back pressure of [_____] kPa (gage) psig or a maximum back pressure
of [_____] kPa (gage) psig. Water rate at full load and normal steam
conditions shall not exceed [_____] kg pounds per brake power hour.
Maximum turbine speed shall not exceed [_____] rpm.
a.
Turbine Construction: Turbine casing split on the horizontal
centerline constructed of ASTM A 48M ASTM A 48 cast iron, with
SECTION 15502N
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