Fiber fabric diaphragm duct introduction The diaphragm air duct is a fabric air duct product which integrates two kinds of air supply methods. The diaphragm is a film made of non-permeable fabric material, the film can be adjusted to the upper part or the lower part by the flip valve. When heating the diaphragm up, can be through the lower side of the hole out of the wind, when the cooling, the diaphragm down, the air can be through the upper side, the micro-pores permeate out of the wind. Bag air duct are more suitable for places with high wind sense and requirements.