Electrically driven air pump has surfaces of housing walls forming pump wheel running gap facing pump wheel with recesses and/or protrusions formed by grooves and beads

摘要

The pump has at least one pump impeller wheel (4) between closely adjacent housing walls (2,3), whereby the running gap (5) formed between the walls passes into an external gradually expanding housing channel or is connected to it by a connector. The surfaces (8,9) of the housing walls forming the running gap facing the pump wheel have recesses and/or protrusions (10) formed by grooves and beads.