With these arrangements, the motor sits in a tunnel which is isolated from air stream. This tunnel passes all the way through casing, which allows unrestricted air movement for motor cooling. This is of particular importance for higher temperature applications. The impellor is mounted onto a precision machined extension shaft, which in turn is mounted onto the motor shaft. Shaft seals are fitted to prevent ingress of dust and minimise air leakage into the motor tunnel. These seals are not gas tight and can be affected by condensation, corrosive chemicals or abrasive materials. Please refer to RHF if special seals are required.
The middle section of the fan casing is enlarged to minimise the restriction of airflow. Coned ends have been carefully proportioned to give a smooth flow from the impellor barrel right through the casing. The use of a one piece spinning for the cone ends ensures accuracy and smooth aerodynamic transitions. These spun cone ends are made from a minimum of 3mm thick steel and are used on all sizes, regardless of whether the casing construction is in mild steel or stainless steel.
Ancillaries such as spigot flanges, inlet bellmouths, casing feet and flexible connections are also available. RHF can offer non standard arrangements/special fans.