Howden - Model D-Series - Cooling Fans
From Cooling Fans
Howden D-series axial cooling fans are designed to operate at peak efficiency at the most common duty points in field erected cooling towers and air-cooled steam condensers.
D-series cooling fan blades have the innovative and patented 'Aerotip' blades developed by Howden. The blades have an integral shaft, are positioned on the fan hub-plate by aluminium blade supports and are fastened by U-bolts for simple field assembly and blade pitch adjustment.
- one-piece fan blade with integral reinforced shaft. This eliminates the concentration of stresses at mechanical joints, which is a major cause of fan failures in operation, and is less sensitive to load variations such as those caused by high winds.
- less risk of resonance compared to aluminium blades or metal blade parts due to the superior dampening properties of Howden glass fibre reinforced polyester. Fan design life is prolonged to up to 40 years
- patented 'Aerotip' blades enhance the aerodynamic performance of the DNF fan and significantly reduce the 'pressure pulse' transmitted to the fan ring.
- accurate and reliable fan performance data. Our fan selection software contains many years of (field) experience and exhaustive cooling fan know-how.
- no need to re-pitch the blades after start-up due to reliable fan software.
- low sound, because of the dampening effect of polyester and the geometry of the blade construction.
- high efficiency resulting in low power consumption, because of optimal blade shapes (determined in the world's most extensive cooling fan test facility).
- lightweight blades, allow simple field assembly and easy individual adjustment of the blade pitch.
- lightweight construction benefits the gearbox cost (lighter bearings potentially save 2-3% off the fan price).
- excellent chemical resistance (suitable for cooling towers using brackish water).
- straight aerofoil designed for clockwise rotation in the horizontal position only.
- available in standard high-efficiency aerofoils (DNF) as well as low-noise aerofoils (DLF and DVF).
- patented 'Aerotip' blade tip design (only valid for DNF fans).
- fan diameters range from 7925mm to 10,973mm (26ft to 36ft)
- standard operating temperature range from -20 to +65oC (-4 to +149oF).
- one-piece glass fibre reinforced polyester (FRP) blades, adjustable at rest. D-Series blades have an integral shaft.
- mild steel polyurethane coated hub plate with aluminium blade clamping pieces and stainless steel U-bolts, nuts and washers.
- polyurethane blade leading edge protection for wet cooling tower applications.
- cast iron, polyurethane coated, standard straight bore or taper lock bore coupling flange (bushing excluded), to suit the mating drive shaft of the gearbox or motor, including galvanized bolting.
- material upgrade for seawater cooling tower applications.