DMF have recently completed a project for BHP at one of their large mine sites in central Australia, supplying and overseeing 8 units of Efaflex high speed spiral doors. The model selected was the STR, which has a 900gsm PVC panel, with closely spaced windbars, and allowing speeds of over 1.5m/sec by tracking around the spiral design. This model has a high wind capacity at 100km/h, remaining fully operational under this wind load, and the doors were 6m in height, and ranging from 6m to 7m in width. The Efatronic controller are a simplified design with fully programmable features, and allow a single phase power source, with invertor control provide a soft start / stop operation of the door. This feature removes considerable loading of the door operation, especially when working at such high speeds with considerable angular momentum of the door blade.
