TYPE CRB - BELT DRIVE DOMED POWER ROOF VENTILATORS, UL705
Power Roof Spun Aluminum Ventilators of Type CRB: The CRB units are quiet, dependable power roof ventilators recommended for a wide range of general exhaust applications where low, medium and high ranges of air volume and pressure are specified. Applications include virtually all types of light manufacturing, commercial and institutional buildings such as shopping centers, hospitals, schools, hotels, office and apartment buildings, warehouses, airports, bus terminals and many others. CRB units are specified where a roof-mounted location is desired to eliminate interference with other equipment or activities in the building. They permit the direct upward venting of air. CRB units may be used with or without ducts. The advantages of a CRB belt-drive over a direct-drive roof ventilator include quieter operation and adjustable performance to suit operating needs and availability of larger volume units.
Construction of CRB fans: CRB models feature a housing of durable spun aluminum for optimum weather protection. The overlapping deep-spun venturi minimizes air turbulence and increases efficiency. The aluminum centrifugal wheel is a non-overloading, backward-inclined type, selected for low noise levels. Backplate fins draw cool air through the motor compartment. The wheel is secured to the machined aluminum hub, and computer balanced on state-of-the-art equipment. Neoprene vibration isolators to reduce noise and wear, and 1/2” galvanized mesh birdscreen are both standard.
Drive & Bearings of CRB fans: The belt driven CRB utilizes a standard V-belt drive design with variable pitch cast iron pulley for adjusting fan speed. Drive shaft is turned, ground and polished. Motor support is adjustable for proper tensioning. Bearings are of heavy duty pillow-block ball bearing design supplied on all CRB units.
Prefabricated Roof Curbs: Insulated roof curbs with weather-resistant continuous welded construction. Available with treated wood nailer, aluminum, or galv. steel construction, 8”, 12”, or 24” high; with dam[per shelf and accordingly pitched to meet roof profile.
Special Motors: ALL SINGLE PHASE UNITS COME WITH OPEN DRIP PROOF MOTORS AS STANDARD AND HAVE BUILT IN THERMAL OVERLOAD PROTECTION . Two-speed, totally enclosed, energy efficient and explosion-proof motors for hazardous locations are available. Motor requirements may affect UL Listing.
Backdraft Dampers: Gravity, or motor operated aluminum back-draft dampers are available.
Safety Disconnects: Safety disconnects to cut power to motor for servicing of unit, available as plug-in internal NEMA1 disconnect, or external NEMA3R/NEMA4 disconnect.