DBF series cabinet fan is specially designed to meet the supply air and exhaust air of different working condition running, according to the seasonal variation and operation condition to adjust the air volume, can save energy consumption. It can supply air to multi-direction air duct at the same time. It has the advantages of stable running, low-noise, small volume, light weight, good-looking appearance, convenient maintenance etc. It is widely used in air conditioning project system of supply air and exhaust air, such as: industrial production, civil construction, business entertainment, education and public health departments. According to the request, the cabinet fan can adjust air volume and air pressure by power pressure regulating or by power frequency conversion. It can be remote controlled after equipped with electric control cabinet. a) DBF-I: external-rotor motor drive and multi-fan structure; supply air to multi-direction air duct at the same time. The vertical type is inlet air horizontally and outlet air vertically upward. b) DBF-II: forward curved multi-blades centrifugal cabinet fan, with a single-fan and belt drive structure, can provide large air volume. c) DBF-III: backward curved plate-type centrifugal cabinet fan, with a single-fan and belt drive structure, and can provide high air pressure. DBF-I, II, III can be assembled with the dust filters in the inlet air according to user's requirements, or addprimary filter, mid-effect filter to be used as a purifying cabinet fan. The dimensions of cabinet can be further designed.