Concave type centrifugal fan air inlet structure

The utility model discloses a structure of an air inlet of a concave centrifugal fan, which comprises a fan volute, a barrel flange matched with the fan volute, a current collector, a flange reducing support frame and a threaded connecting piece, the barrel flange is fixedly connected to the input end of the fan volute, and a plurality of connecting through holes are formed in the barrel flange; the current collector is fixedly connected to the flange supporting frame; the flange variable-diameter supporting frame is of an inwards-concave structure and is fixedly installed on the flange with the barrel through the threaded connecting piece, and the flange variable-diameter supporting frame comprises a support ring arranged on the current collector, a base plate arranged on the support ring, a conical ring arranged on the base plate and a side wing ring arranged on the conical ring. 本实用新型公开了一种内凹式离心风机进风口的结构，包括风机蜗壳、与所述风机蜗壳配套的带筒法兰、集流器、法兰变径支撑架及螺纹连接件，所述风机蜗壳的输入端上固接有所述带筒法兰，所述带筒法兰上设有多个连接通孔；所述集流器固接于所述法兰支撑架上；所述法兰变径支撑架呈内