Abstract: The invention relates to a cover plate (2) for a screw-type centrifugal wheel pump (1), wherein the cover plate (2) has a front side (2h) and a rear side (2i), and wherein the front side (2h) comprises a surface part (2k) which runs in a preferably frustoconical manner and the profile of which is designed to be matched to the rear side of a screw-type centrifugal wheel (25), wherein the surface part (2k) has, in the center thereof, a central opening (2g), wherein the central opening (2g) runs in the direction of an axis (A), and wherein the cover plate (2) has at least one aperture (2a) which is arranged in the region of the surface part (2k) and spaced apart from the central opening (2g), and wherein the aperture (2a) forms a fluid-conducting connection between the front side (2h) and the rear side (2i) of the cover plate (2).

Abstract: The screw-type centrifugal wheel pump includes a pump housing and a screw-type centrifugal wheel arranged rotatably within the pump housing and having a hub and a blade, and comprises a rotatable drive shaft connected to the screw-type centrifugal wheel, and includes a cover plate arranged between the screw-type centrifugal wheel and a housing rear wall, wherein the cover plate has a central opening through which the hub or the drive shaft runs, and wherein an interior space is formed between the cover plate and the housing rear wall, wherein a gap is formed between the central opening of the cover plate and the hub or the drive shaft, which gap is connected in fluid-conducting fashion to the interior space, wherein the cover plate has at least one aperture, which is arranged spaced apart from the central opening, in order to generate a fluid flow which flows into the interior space via the aperture and out of the interior space again via the gap.