摘要:
The unit has a conveying pump embodied as a flow pump (10) with an impeller wheel (12) rotating in a pump chamber (24) and having respectively a crown of vanes (32) on both of its front faces which, together with grooves (38, 24) in the shape of a partial circle arranged in the front walls (26, 28) delimiting the pump chamber (24), respectively constitute a lateral conveying channel (44). The vanes (50) of the impeller wheel (12) are connected by an outer ring (36) on their radially outer ends. The outer ring (36) of the impeller wheel (12) also has a crown of vanes (50) which, together with the grooves in the shape of a partial circle arranged in the front walls (26, 28), respectively constitute an outer flow channel (58). Over a portion of their circumference the outer flow channels (58) are connected with the conveying channels (44) and, together with them, a pressure build-up in the direction of rotation (11) of the impeller wheel (12) approximately corresponding to the pressure build-up in the conveying channels (44) takes place, so that there is essentially no pressure difference between them, by means of which the entry of dirt into the area between the outer ring (36) of the impeller wheel (12) and the front walls (26, 28) is prevented.