DFO-103 - page 51

Provideahighperformance, lowmaintenance, centrifugal
fanwithairfoil wheel andhyperbolicwheel cone.Fanshall
be licensed to bear the AMCACertified Ratings Seal for
Air Performancebasedon tests andprocedures inaccor-
dancewith AMCA standard 211. Fansmust bemanufac-
tured and assembled in the U.S.A. Acceptable vendors:
ChicagoBlower Corporation.
Performance shall include steep pressure and non-over-
loadinghorsepower characteristics.Mechanical efficiency
shall beno less than80%.Wheel inlet cone tobedesigned
toensuresmooth, stableair flowacross theentireoperat-
ing range. System static pressure changes of 30% shall
result inanapproximate10%volume reduction.
Fanhousingshall beofwelded, heavygaugeconstruction
with seven common discharge positions. Scroll is to be
continuously welded. Bearing supports shall be heavy
gauge steel bar bolted to fan housing for easy removal of
the rotor.
Wheel shall havecast ironor cast steel hubhuckbolted to
aheavy centerplate.Airfoil blades continuouslywelded to
the centerplate and hyperbolic wheel cone.Wheels to be
statically and dynamically balanced toG6.3 standards in
accordancewith ISO1940andANSIS2.19specifications.
Shaft shall be turned, groundandpolished1045hot rolled
steel straightened toamaximumT.I.R.of .002 inchesand
mounted using heavy duty ball or roller pillowblock bear-
ings. Shaft critical speedshall not be less than1.25 times
Housingandbaseassemblycompletewith integralmount-
ingangles for connection to foundation.
If motors and drives are to be factorymounted unit to be
testedat runningspeed for vibrationandbalance.Filtered
vibrationreadings, takenat fanbearingsandmotorbearings,
arenot toexceed0.15 inches per second.
Inlet volume control (IVC) device shall be totally enclosed
within the inlet cone. IVC device shall be 7-bladed, and
pre-spin the incomingair to control volumeandpressure.
• FlangedOutlet - PunchedHoles
• CompanionFlange - Punchedor Unpunched
• Spherical Roller or Ball BearingswithL10 lifeof
• Split PillowBlockBearings
• Type “C”AMCASparkResistant Construction
• 1-1/2" NPTHousingDrain
• QuickClampor RaisedBoltedAccessDoor
• Inlet Screen
• AdjustableMotor Base
• ExtendedGreaseFittings
• TotallyEnclosedBelt GuardwithVentilationPanel
• Constant or AdjustableSpeedV-Belt Drives -
• Outlet Damper - Parallel orOpposedBlades.Manual
OperationwithLockingQuadrant orAutomaticOperaton.
• Horizontal HousingSplit
• UnitaryBase:Heavy channel construction, continu-
ouslywelded, with fanandadjustablemotor base
welded, to insure vibration-free service.
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