* model 4-72 centrifugal fan can convey air and other non-hypergooic gas which are not harmful to the human body and will not corrode steelmaterials. the adhesive materials are not allowed in the gas. its containing dust and hard particles should not exceed 150mg/m., gas tem-perature not exceed 80`c.it has sound pneumatic performance. there-fore it has features such as balanced running little vibration，high efficiency, long life etc. it is widely applicable, large-size architectures, guesthouses, restaurants, etc.
* model b4-72 is an explosion一proof type centrifugal fan.it is mainly composed of aluminum pad die-wheel, casing, air inlet etc. and the explosion-proof motor. it can beused as ventilation and air-exch ange to the inflammable and volatilizing gas. its performance and foundation size are the same as mode 4-72.
* model f4-72 is anti-corrosion centrifugal fan. it mainly uses fiberglass( orstainless steel)to make up the impeller, casing, air inlet etc, then combine with motor.lt can be used to convey the corrosive gas. the performance and foundation size are same as model 4-72.