Volute-free centrifugal fan

The utility model belongs to the technical field of ventilator equipment, and particularly relates to a volute-free centrifugal fan, which comprises a box body, the box body is a cubic frame with openings on two sides, one opening is an air inlet, the other opening is an air outlet, a protective net is arranged at the opening of the box body, a pressing block is arranged above the opening of the box body, a fastening block is arranged inside the pressing block, and the fastening block is connected with the box body. The fastening block is connected with the spring and located in the pressing block, the pressing block can fix the protective net, a cleaning device is arranged below the pressing block and comprises a moving rod and a sliding block, the moving rod is connected with the sliding block, the sliding block is arranged in the moving air cylinder in a sliding mode, and a dust storage box is arranged below the moving rod. And when excessive dust is accumulated on the protective net, the dust needs to be