For the cone part, adopt new design, plug type connection, not need many bolts and nuts for tightening as before, intensity of labor is reduced, also improve aesthetic results of fan

The belt tensioned device made of aluminum magnesium alloy, on deforming, long service life. This device make the belt inside tight up, effective for avoiding the belt distortions in reverse direction

When the two semicircle shutter doors close, the rubber sealing ring make good air tightness.In different condition, not run all the fan, the air could pass through the space of stop fan, use this type fan, could avoid this problem.

fan motor installed on the top left corner, effective protection of the motor. Avoid wind resistance. And the motor panel connection is reasonable, fixing fan frame stronger.