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Provide factory fabricated multilouver dampers with [parallel] [or]
[opposed] blade type operation. Construct damper frame of distortion
resistant welded steel channels with raised seat to ensure free nonbinding
operation of blades and to keep blades square in the frame. Construct
blades of 6 mm 1/4 inch thick steel plate in a stressed skin airfoil-shape
with fully welded seams containing no external ribs. Blade shafts shall be
stainless steel. Blades shall be pinned to blade shafts. Louver shaft
bearings shall be outboard type and shall be self-lubricating and
self-cleaning. Bearing seals shall be gas-tight.
a.
Multilouver Damper Linkage: Damper linkage shall be adjustable
and of pinned construction for easy removal and shall be designed
to handle full operation torque. Linkage on dampers in clean flue
gas areas shall operate from a single connection point. Design
linkage on dampers in dirty flue gas areas, between boiler outlet
and inlet to air pollution equipment, so that the bottom blade
linkage arm is not connected to the above linkage, to allow this
blade to operate separately. The remaining linkage for this
damper shall be constructed to operate from a single operating
point.
b.
Control Damper Operators: Provide control damper operators as
noted. Operators may be either electrically or pneumatically
operated with positive positioning, manual override, and hydraulic
or oil immersed gear trains. Each operator shall be
full-proportioning type, with spring return to position indicated
in case of loss of power. Damper operating speeds shall be
selected or adjusted so that the operators will remain in step
with the controller. Operators acting in sequence with other
operators shall have adjustment of control sequence as required by
the operating characteristics of the system.
c.
Two-Position Damper Operators shall be pneumatically operated with
air cylinder, four way valve, and solenoid valve arrangement.
2.7.4.2
Guillotine Dampers
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NOTE: Guillotine dampers shall be used for
open-shut service where tight shutoff is required;
for example, for air pollution control equipment
bypass dampers.
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Provide factory fabricated guillotine dampers with heavy structural frame
rigid enough to support the extended blade and external loads through the
breeching flange. Damper shall be capable of operating without precleaning
or manual assistance under normal operating conditions. Enclosed bonnets
will only be required where indicated. Provide three inch diameter
cleanout ports on both sides for cleaning bottom sections.
a.
Guillotine Damper Blades: Provide stress-relieved flat plate
guillotine damper blades. Damper blade shall be nonwarping.
Intermediate blade supports are acceptable to limit blade
deflection. The leading edge of the damper blade shall be beveled
and capable of guiding damper blade into frame seat. Blade guides
shall be continuous and self cleaning and capable of preventing
SECTION 15511N
Page 47
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