- Fan Type
The fan shall be the centrifugal fan which adopts backward inclined centrifugal wheel. The drive type shall be direct-drive or belt-drive. The fan shall use aluminum backward inclined centrifugal wheel, and shall include a wheel cone carefully matched to the inlet Venturi for precise running tolerances. The wheel shall be statically and dynamically balanced to Level G2.5 as per AMCA204 standard.
- Quality Standards
The fan shall be tested in accordance with AMCA Standard 210 and 300. The manufacturer must own the production license for industrial products and ISO9001 quality system authentication.
- Wind Band
The wind band shall be constructed of heavy gauge galvanized steel with [or: stainless steel] a rigid internal support structure. The wind band profile shall be of the streamline type; the structure shall be of the multi reinforced rib type to protect the fan from wind overload; and the external surface shall be pitched to quickly drain rain and snow by gravity.
- Upward Air Intake
The fan inlet shall have upward air intake to make sure rain would not be sucked into the fan body as well as the building.
Motor shall be carefully matched to the fan load and its protection grade shall be IP54, while insulation class F and temperature rise B. The motor bearing shall be self-lubricating ball bearing. And TEFC, 2-SPD, EXP, VFD, 60Hz and other correct motor types must be selected according to the specific working conditions.
- Transmission Device (Only for belt drive type)
Shaft: Fan shaft shall be heat treated through soaking furnace to reach the hardness level of HB250, and the surface shall be hard film corrosion treated. The fan shaft shall be balanced together with the wheel, and the shaft design speed shall at least exceed 25% of the maximum fan operation speed.
Pulleys: Fan pulleys shall be sized for a minimum of 150% of driven power. Pulleys shall be cast iron. Motor pulleys shall be adjustable for final system balancing. Conical (QD) type bushing shall be equipped for easy removal of the pulleys.
Bearing: Bearings shall be selected of metallic to avoid vibration directly applied to motor. The motor bearings shall be selected for a minimum (L－10) life in excess of 80,000 hours at maximum cataloged operating speed. Bearing type shall be permanently sealed, lubricable pillow block metal ball bearings.
Drive support: Drives shall be supported by powder coated heavy gauge steel and mounted on vibration isolators. The belt tension shall be adjusted through motor support plate to make sure the fan shaft and motor shaft always parallel.
Permanently fixed aluminum nameplate shall be fixed on fan body clearly display fan mark, product model and serial number (i.e.: unique ID for each fan), so that the customer can use this number to find out the parts used.
- Acceptable Manufacturers
Qualified suppliers shall have an AAA credit rating. Providing INFINAIR or similar products, with their design based on YFRSC models of INFINAIR.