This arrangement has a shaft and bearings supporting an overhung impellor. The bearings and shaft are outside of the airstream. The hub of impellor protrudes from the casing. The fan unit is mounted onto a channel frame, along with motor and slide rail unit & belt drive. The drive guard and support are neatly integrated with the fan unit and channel base. The channel base comes in 2 variants, one with outriggers and one without. Outriggers enable easy drilling of foundation holes without having to mark and then move the fan.
The inner casing is completely contained within another casing. Maximum air temperature is 350ºC (50mm lagging) – 450ºC(100mm lagging). The impellor can be removed from inlet side only. This casing has 2 further variants, one where the lagging is cut back at the discharge and one where the inlet flange is unlagged.