current production standards. High stress fan wheels shall be
continuously welded. Low stress exterior housing bracing,
dampers, and other similar components shall be intermittently,
plug or continuously welded.
e.
Painting: Interior of fan, including wheel, shall be coated with
protective coatings suitable for the flue gas conditions expected
to be encountered by this fan. Exterior surface of fan shall have
coatings of quality weather and heat resistant paint. Fan shall
be shop assembled and match-marked by manufacturer before
dismantling for shipment. Surface cleaning and painting shall be
in accordance with the manufacturer's standards for the service
expected.
2.6.2.3
Fan Drive
Fans shall be equipped with [both] [a motor] [and] [steam turbine] drive.
The [motor] [and] [turbine] shall be directly 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
with a 1.5 service factor. Provide a removable guard over each clutch
coupling].
2.6.2.4
Electric Motor
Motor for driving the induce draft fan shall be [_____] volt, three phase,
60 Hz, [open drip-proof,] [totally enclosed fan cooled,] variable speed not
less than [_____] kW hp, as specified under paragraph entitled "Motors and
Drives" in this section, and shall not overload over the range of the fan
with unheated 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 each of the four
motor mounting bolts. Separate parallel soleplate bars are not acceptable.
2.6.2.5
Steam Turbine
Steam turbine shall drive the fan through a reduction gear and shall be
single stage, rated at not less than [_____] kW hp, with inlet steam
pressure of [_____] kPa (gage) psig, [_____] degrees C Fotal 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 shall be split on the
horizontal centerline constructed of ASTM A 48M ASTM A 48, cast
iron, with design pressure rating of 1724 kPa (gage) 250 psig at
232 degrees C 450 degrees F at the inlet, and 379 kPa (gage) 55
psig at 232 degrees C 450 degrees F at the outlet. Turbine shall
include a stainless steel steam strainer, sentinel relief valve,
b.
Turbine Bearings and Shaft. Turbine bearings shall be
horizontally split, ring-oiled, sleeve type water-cooled. Shaft
shall be stainless steel sprayed or chrome plated under the
packing glands.
Shaft seals shall be segmented carbon rings with
SECTION 15502N
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