Abstract: A floating-ring seal in a seal chamber is disposed on a pump casing at said end of a housing on the side remote from said pump. The seal chamber is isolated from the pump side by a contact seal element that is seated close to a rotating pump part. The seal chamber has a cooling circuit that is preferably filled with a fluid that is identical to the pumping medium. The seal chamber is separated from pumping medium by the seal element. A pressure compensation device is disposed in the region of the seal element in case fluid leaks from the seal chamber. The pressure compensation device fills the seal chamber with pumping medium to compensate for the leaked fluid.

Abstract: A bearing arrangement at the intake aperture of a centrifugal pump impeller in which a bearing shell (5) arranged in the housing (4) can be fitted from outside the pump. The bearing shell (5) is positioned by a retainer (7) and the flange (10) of a pipe to be connected thereto.

Abstract: A multi-stage centrifugal pump wherein a casing surrounds an impeller and a fluid flow guiding insert in each pump stage. The casing is made of a ferritic material, and the inserts are made of an austenitic material. The casing defines with each insert a first clearance wherein a cylindrical surface of the casing is surrounded by a cylindrical surface of the respective insert so that the width of the clearance increases in response to heating of the inserts and of the casing at the respective first clearances. The casing further defines with each insert a second clearance which is disposed radially outwardly of the respective first clearance and wherein a frustoconical surface of the casing surrounds a complementary frustoconical surface of the respective insert so that the width of each second clearance decreases in response to heating of the casing and of the inserts at the respective second clearances.

Abstract: The inlet and/or outlet edge of a blank which is to be converted into the vane of an impeller for use in a centrifugal pump is reinforced by providing an exposed surface of the blank with a pair of contiguous recesses which extend along the edge and the deeper of which is immediately adjacent to the edge. The recesses are then filled with metallic armoring material by cladding so that some of the surplus extends beyond the recesses and/or beyond the edge. In the next step, the surplus of armoring material is removed by one or more material removing tools, together with a portion of the blank in the region of the edge so that the exposed surface is provided with a fresh edge which is defined by the armoring material.