Damper - page 2

The InletVolumeControl (IVC) is adevicedesignedbyChicago
Blower toalter fanperformance.Closing the IVCspins inlet air
in thedirectionof thewheel rotationand reduces the flowand
pressurewhile travelingdown the fan’s systemcurve.This keeps
the fan ina stableoperating condition.Chicago’s IVCs canbe
utilizedonopen inlet fans, aswell as fanswith inletboxes.
Chicago’s IVCconsists of 7or 9pie-shapedblades nested
insidean inlet cone, welded to full lengthaxles.Thesepivot on
prelubricatedbronzebearings locatedwithina coveredoperating
mechanismpositioned in the center of the inlet cone. IVCs are
furnished formanual control witha lockingquadrant or for auto-
matic operationusinganelectric or pneumatic actuator.On
double inlet fans, interconnecting linkageassures coordinated
operation.
Standard IVCs are suitable for applications to200°F.They should
not be considered zero leakage.Anoptional low-leakage IVChas
tighter clearances resulting inadditional turn-down capabilities.
Outlet dampers areprimarily utilized for shut-off and isolation,
but canalsoassist inachievinggreater turndownwhen com-
binedwithan IVCor inlet damper.They arenot recommended
as theprimarymodulationdamper as the closureof these
dampers alter the systemcurve,moving it towards thepeak
pressurepoint and resulting inanunstable condition.The
damper has double surfacedbladeswelded to full lengthaxles.
Theblades rotatewithanopposedaction toeachother, thereby
creatinga straight air flow. Theblades are fully contained
withinaheavy-duty, formed steel channel frame sized to
match the fandischarge, evase´ or stack opening.The shafts
rotate through the flangedbearings.
For installations inexcess of 200°F, dampers rotate through long
lifepillowblock bearingsmountedon stand-off channels, and
protectedby stuffingboxeswithbraided fibrous packing topre-
vent leakageat the shaft holes in the frame.Blades, axles and
frames canbe coatedwithany number of coatings, or
constructedofmild steel, or 304and316 stainless steels
dependingon the temperatureandapplication
Inlet Volume Control
Outlet Dampers
1 3,4
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