Abstract: The free-flow pump comprises an impeller (11, 22, 33) with an impeller base that is constituted by a front side (14, 5 24) of a hub body (12, 23) projecting at the center of the impeller (11, 22, 33) and by a disk surface (18, 28) located deeper than the front side (14, 24) of the hub body (12, 23) and reaching to an outer circumference of the impeller with its maximum depth. The disk surface (18, 28) is provided with vanes (19, 29, 34) comprising open vane front sides (20, 30, 35) adjoining the hub body (12, 23) at their inner end and extending from there to the outer circumference of the impeller (11, 22, 33). To avoid material accretions in front of the impeller (11, 22, 33) it is suggested that at least within an inner third of its radius, the impeller base is not located deeper with respect to the inner end of the vane front sides (20, 30, 35) than at most one sixth of the height difference (H) between the inner end of the vane front sides (20, 30, 35) and the maximum depth of the disk surface (18, 28).

Abstract: The free-flow pump comprises an impeller (11, 22, 33) with an impeller base that is constituted by a front side (14, 5 24) of a hub body (12, 23) projecting at the center of the impeller (11, 22, 33) and by a disk surface (18, 28) located deeper than the front side (14, 24) of the hub body (12, 23) and reaching to an outer circumference of the impeller with its maximum depth. The disk surface (18, 28) is provided with vanes (19, 29, 34) comprising open vane front sides (20, 30, 35) adjoining the hub body (12, 23) at their inner end and extending from there to the outer circumference of the impeller (11, 22, 33). To avoid material accretions in front of the impeller (11, 22, 33) it is suggested that at least within an inner third of its radius, the impeller base is not located deeper with respect to the inner end of the vane front sides (20, 30, 35) than at most one sixth of the height difference (H) between the inner end of the vane front sides (20, 30, 35) and the maximum depth of the disk surface (18, 28).

Abstract: An impeller plate of an impeller of a centrifugal pump, particularly a channel impeller pump, for pumping liquids with solid or gaseous admixtures, is provided with at least one wide vane that is displaced toward the impeller drive by a distance D so that the impeller chamber is enlarged by a rearward portion thereof. In addition, the impeller comprises at least one auxiliary vane having a center width at between 25%-75% of the width of the wide vane. This arrangement improves particularly the gas transporting ability of the pump.

Abstract: An impeller plate of an impeller of a centrifugal pump, particularly a channel impeller pump, for pumping liquids with solid or gaseous admixtures, is provided with at least one wide vane that is displaced toward the impeller drive by a distance D so that the impeller chamber is enlarged by a rearward portion thereof. In addition, the impeller comprises at least one auxiliary vane having a center width at between 25%-75% of the width of the wide vane. This arrangement improves particularly the gas transporting ability of the pump.

Abstract: The free-flow pump has an impeller housing (9, 10) laterally of its free flow chamber (4), and the impeller (6) is located in the impeller chamber (9, 10). The external, radial limiting member (10) of the impeller housing is drawn forwardly into the free flow chamber so as to decrease in the direction of rotation from the housing tongue (11) to the pressure pipe outlet. The limiting member (10) causes a constriction in the external portion (4') of the flow chamber, and such constriction decreases from the housing tongue towards the pressure pipe outlet. These measures permit the pump characteristics to be improved, and in particular the throttle characteristic of the free-flow pump can be stabilized.