Laserfiche WebLink
D. Belt-Drive Units: Motor mounted on adjustable base, with adjustable sheaves, enclosure around belts within fan <br /> housing,and lubricating tubes from fan bearings extended to outside of fan housing. <br /> E. Wheel: Aluminum,airfoil blades welded to aluminum hub. <br /> F. Accessories: The following accessories are required as indicated: <br /> 1. Companion Flanges: For inlet and outlet duct connections. <br /> 2. Fan Guards: Expanded metal in removable frame. <br /> 3. Speed Control: Variable speed switch with on-off control and speed control for 100 to 50 percent of fan air <br /> delivery,as indicated or required. <br /> 2.05 CENTRIFUGAL ROOF VENTILATORS <br /> A. General Description: Belt-driven or direct-drive as indicated, centrifugal consisting of housing, wheel, fan shaft, <br /> bearings,motor and disconnect switch,drive assembly,curb base,and accessories. <br /> B. Housing: Heavy-gage, removable, spun-aluminum, dome top and outlet baffle; square, one-piece, hinged, <br /> aluminum base with venturi inlet cone. <br /> 1. Upblast Units: Provide spun-aluminum discharge baffle to direct discharge air upward, with rain and snow <br /> drains. <br /> C. Fan Wheel: Aluminum hub and wheel with backward-inclined blades. <br /> D. Belt-Drive Assembly: Resiliently mounted to the housing,with the following features: <br /> 1. Pulleys: Cast-iron,adjustable-pitch. <br /> 2. Shaft Bearings: Permanently lubricated,permanently sealed,self-aligning ball bearings. <br /> 3. Fan Shaft: Turned,ground,and polished steel drive keyed to wheel hub. <br /> 4. Fan and motor isolated from exhaust air stream <br /> E. Accessories: The following items are required as indicated: <br /> 1. Disconnect Switch: Nonfusible type, with thermal overload protection mounted inside fan housing, factory- <br /> wired through an internal aluminum conduit. <br /> 2. Bird Screens: Removable Y2-inch mesh, 16-gage,aluminum or brass wire. <br /> 3. Dampers: Counterbalanced,parallel-blade,backdraft dampers mounted in curb base,factory set to close when <br /> fan stops. <br /> 4. Dampers: Motor-operated,parallel-blade,volume control dampers mounted in curb base. <br /> a. Blades: Die-formed sheet aluminum <br /> b. Frame: Extruded aluminum,with waterproof,felt blade seals. <br /> C. Linkage: Nonferrous metals,connecting blades to counter weight or operator. <br /> d. Operators: Manufacturer's standard pneumatic motor. <br /> 5. Roof Curb: Provide with a factory pre-fabricated roof curb. <br /> 15850-5 No.99132-CP2 <br />