separately. Remaining linkage for this damper shall be
constructed to operate from a single operating point.
b.
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
operators will remain in step with controller. Operators acting
in sequence with other operators shall have adjustment of control
sequence as required by operating characteristics of system.
c.
Two-position damper operators shall be pneumatically operated with
air cylinder, four way valve, and solenoid valve arrangement.
2.8.4.2
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 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 80 mm 3 inch diameter
cleanout ports on both sides for cleaning bottom sections.
a.
Provide stress-relieved flat plate guillotine damper blades.
Damper blade shall be nonwarping. Intermediate blade supports are
acceptable to limit blade deflection. Leading edge of 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 binding from deposits and damage from
misalignment. Bonnet guides shall be removable. Design damper so
that a damper blade can be replaced without opening the frame.
b.
Provide guillotine damper bonnet seal to effectively seal against
atmospheric leakage under normal operating conditions.
c.
Guillotine damper drive shall be a positive dual endless chain
drive capable of driving damper in both directions. Chain drive
headshaft shall have sufficient torsional rigidity to prevent
binding of blade when blade is stalled. Damper shall be motor
operated with manual override. Design drive mechanism to prevent
back driving of motor. Entire drive mechanism shall be of a
simple design and require no routine maintenance other than
inspection. Chain shall be capable of operating up to the stall
torque of the damper drive motor.
d.
Electric motor shall be [_____] volt, [_____] phase, 60 Hz,
[totally enclosed, fan cooled] [open drip-proof], not less than
[_____] kW hp, as specified in paragraph entitled "Motors and
Drives." Provide removable, totally enclosed chain guard.
SECTION 15501N
Page 66
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