Passive supply air duct with gravity butterfly valve

Mine supply CFI has an aerodynamic shape and is made of plastic resistant to aggressive environment of livestock buildings. The shaft has a smooth surface with a dirt-repellent property and is easy to clean. CFI shaft with rainproof umbrella and roof slab - resistant to sunlight and low temperatures. Protective net from wild birds made of plastic, not subject to frost. The shaft body has a multilayer structure of the type “sandwich panel”. The internal cavity is filled with foamed polyurethane with a thickness of 45 to 50 mm, depending on the diameter of the shaft. It is possible to lengthen the duct in sections of 500 mm, 1000 mm, 1500 mm.