Impellers
Blades
The blades have been designed for optimal performance, for both aerodynamic needs as well as noise characteristics. They are available in a range of materials as shown below:-
Impeller Ranges
Range of diameters |
No. of blades |
Hub Dia (mm) |
Materials |
315 to 900 |
5 or 10 |
150 |
GRP, Nylon, Aluminum, Anti-static GRP |
560 to 1000 |
7 or 14 |
250 |
GRP, Nylon, Aluminum, Anti-static GRP |
800 to 1250 |
3 or 6 |
255 |
GRP, Nylon, Aluminum, Anti-static GRP |
800 to 1400 |
3, 6, 9, or 12 |
350 |
GRP, Nylon, Aluminum, Anti-static GRP |
1000 to 1800 |
3, 6, or 9 |
400 |
GRP or Aluminum |
1250 to 2000 |
3, 6, 9, or 12 |
550 |
GRP or Aluminum |
The stress limits of the blades vary from one material to another and simplified criteria are incorporated on the curves. However, if selecting fans using our interactive product selection CD, you may find solutions with higher pitch angles are chosen; these selections are quite acceptable.
It should be noted that, as we are constantly reviewing the materials we use, these limits may be extended.
Hubs
All hubs use Fantech TECH-LOCK® taper bushes as standard with one exception. The bush ensures ease of fitting and removal of the impeller from the motor shaft should adjustment of the pitch angle, cleaning or repair of the impeller prove necessary. The exception is for bores above 65mm and 85mm diameter for the 400mm and 550mm diameter hubs respectively. In these cases we supply impellers with simple through-bores.
Fixings
All impellers are assembled using high-tensile, zinc-plated set screws and self-locking nuts.
Handing
Right and left-hand blades are available enabling the selection of contra-rotating or multi-stage axial flow fans up to 1400mm diameter. If contra-rotating fans of a larger diameter are required please refer to our sales department.
Standard Material
GRP blades will be supplied for normal clean ventilation applications as standard except where otherwise specified, or where local regulations prohibit their use.
Balance
The balance of all impellers is carefully checked to ensure vibration-free running.
Fully-adjustable Blades
All impeller pitch-angles are fully adjustable. For the Elta Range, up to size 1400, the required blade angles are set on jigs but for sizes up to 100, may also be set utilising the graduated scale at the root of each blade. For the Elta 2000 Range pitch angle setting is by protractor.