2.11.4.5
Induced Draft Fan
Performance of the induced draft fan shall be as specified in paragraph
entitled "Design Parameters." Induced draft fans shall be double inlet,
double width. Provide one induced draft fan for each steam generator and
its associated gas cleaning equipment as indicated. Each induced draft fan
shall be equipped with dampers as specified in paragraph entitled
"Mechanical Draft Equipment." Provide inlet control dampers for regulating
the fan output. Inlet dampers shall be arranged for operation from one
control drive at each fan. Control drive shall be as specified in
paragraph entitled "Analog Control System." Provide control signal from
combustion controls. Induced draft fans shall have housing constructed of
10 mm 3/8 inch minimum thick mild steel. Housing shall be provided with
wear-resistant liners of not less than 12.70 mm 1/2 inchthickness at all
points of wear. Liners shall be easily replaceable. Interior bolt heads
shall be protected from fly ash erosion. Fabricate housing of 19 mm 3/4
inch minimum thick, mild steel plate instead of separate liner plates, if
desired. Induced draft fan rotors shall have radial blades with replaceable
wearing surfaces over at least two-thirds of the blade width, at least
equal to the thickness of the skin of the blade.
2.11.4.6
Reverse Air Fan
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NOTE: Insert appropriate Section number in the
blanks below.
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The reverse air fans shall be heavy duty industrial type fans having single
flanged inlets and outlets. Type of bearings and bearing lubrication shall
be suitable for the temperatures encountered. Provide heat slingers. A
quick-release gasketed inspection door shall be furnished on the housing.
Fans shall be V-belt driven by a constant speed motor through adjustable
speed sheaves. Mount motor on slide motor bases designed to adjust belt
tension from a screw mechanism; furnish suitable belt guards. The fan
shall be rated for flow, pressure, power, speed of rotation, and efficiency
in accordance with AMCA 210 and the fan shall comply with AMCA 201 and the
fan shall comply with AMCA 99. Motors shall be as specified in Section
[_____] ELECTRICAL, for the service intended. Minimum reversing air flow
shall be with 10 L/s per square meter 2 acfm per square foot of net cloth
area under cleaning action.
2.11.5
Painting
Surfaces of ductwork and metal parts of expansion joints which will be
exposed after installation of insulation and lagging shall be painted as
specified in paragraph entitled "Ductwork and Draft Equipment." Areas that
will not be exposed shall be painted as specified, except that a dry film
thickness of 0.051 mm 2 mils shall be applied. Apply primer to steel
surfaces, except the areas within 50 mm 2 inches adjacent to field welds.
Surfaces that will be exposed to the flue gas flow need not be painted, but
shall be protected during shipment and storage with a suitable
rust-preventative coating. Damper frames, support steel and seal air
ductwork not directly in the gas stream shall be shop-cleaned and painted
as specified in paragraph entitled "Structural and Miscellaneous Steel."
Damper operators, seal air valve operators, motors, seal air fans and limit
switches shall be primed and painted per the equipment manufacturer's
standard practice. Protect exposed machined surfaces with a suitable
rust-preventative compound.
SECTION 15864N
Page 78
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