Patent ID: 9709071
Date: 2017-07-18
CPC Classifications: F04C,F04D,F05D

Claim:
1. A screw-type centrifugal wheel pump ( 1 ) comprising a pump housing ( 3 ) with a pump inflow opening ( 3 a ) and with a housing rear wall ( 23 ) arranged opposite the pump inflow opening ( 3 a ), comprising a screw-type centrifugal wheel ( 20 ) which is rotatably arranged within the pump housing ( 3 ) and which has a hub ( 21 ) and an impeller ( 25 ), and comprising a rotatable drive shaft ( 33 ) which is connected to the screw-type centrifugal wheel ( 20 ) and which is rotatable about an axis of rotation (A), and comprising a cover plate ( 2 ) which is arranged between the screw-type centrifugal wheel ( 20 ) and the housing rear wall ( 23 ), wherein the cover plate ( 2 ) has a central opening ( 2 g ) through which the hub ( 21 ) or the drive shaft ( 33 ) extends, and wherein an interior space ( 37 ) is formed between the cover plate ( 2 ) and the housing rear wall ( 23 ), wherein the cover plate ( 2 ) has a front side ( 2 h ) oriented toward the pump inflow opening ( 3 a ), and wherein the front side ( 2 h ) comprises a partial surface ( 2 k ) the form of which is implemented adapted to a rear side ( 25 a ) of the screw-type centrifugal wheel ( 20 ) in such a way that a first gap ( 24 ) of maximally 3 mm is formed between the front side ( 2 h ) of the cover plate ( 2 ) and the rear side ( 25 a ) of the screw-type centrifugal wheel ( 20 ), wherein between the central opening ( 2 g ) of the cover plate ( 2 ) and the hub ( 21 ) or the drive shaft ( 33 ) there is formed a second gap ( 2 b ), which is connected in fluid-conducting fashion to the interior space ( 37 ) and to the first gap ( 24 ), wherein the cover plate ( 2 ) has at least one aperture ( 2 a ) which is arranged and spaced apart from the central opening ( 2 g ), wherein the screw-type centrifugal wheel ( 20 ) and the arrangement of the aperture ( 2 a ) are embodied and adapted to one another such that the rear side ( 25 a ) of the screw-type centrifugal wheel ( 20 ) does not cover the aperture ( 2 a ) or covers the aperture ( 2 a ) only over a partial angle in a rotation of the screw-type centrifugal wheel ( 20 ) through 360°, and wherein the aperture ( 2 a ) forms a fluid-conducting connection between the front side ( 2 h ) and the interior space ( 37 ) in order to generate a fluid flow (F 1 ), which flows into the interior space ( 37 ) via the aperture ( 2 a ) and then flows out of the interior space ( 37 ) via the second gap ( 2 b ), wherein the hub ( 21 ) has a protrusion which covers the partial surface ( 2 k ) partially with the result that the first gap ( 24 ) is formed between the hub ( 21 ) and the partial surface ( 2 k ) and wherein the first gap ( 24 ) runs transversely with regard to the axis of rotation (A).