The characteristics of DD size multi-blade centrifugal fan are:1. The impeller is multi-blade style with stability adjustment of high-speed running, large blowing rate and low noise. 2. The main case is punch formed by precision mold, and passed electrophoresis procession, so the appearance is exquisite. 3. It is equipped with high efficiency motor through direct-coupled installation with stable performance. 4. The optimally designed air flue can save energy greatly. It can applied to support industrial mechanical equipment, such as wood-working machine, packaging machinery, electronic equipment, UV drying equipment, printing machinery, plastic machinery, purifying equipment and other special equipment for air supply, air exhaust and wind circuit.