Volute type centrifugal fan

The utility model discloses a volute type centrifugal fan which comprises a volute and a centrifugal wind wheel, and the centrifugal wind wheel is rotatably installed in the volute. A flow blocking ring is arranged at the top of the centrifugal wind wheel in a protruding mode, an installation groove is formed in the inner wall of the volute in an inwards-sunken mode, and the installation groove is used for containing the flow blocking ring. An operation gap is reserved between the installation groove and the flow blocking ring, and the distance between the inner groove wall of the installation groove and the inner side wall of the flow blocking ring is smaller than or equal to 2 mm. According to the volute type centrifugal fan, loss of main airflow energy can be effectively reduced, so that the purpose of improving the efficiency of the fan is achieved, meanwhile, airflow entering the centrifugal wind wheel can integrally flow more smoothly, and the volute type centrifugal fan is simple and reasonable in stru