Abstract: A casing which admits the fluid medium into the range of the impeller or first impeller in a fluid flow machine, particularly in a centrifugal pump, is made of several sections which have abutting surfaces. At least one such surface has a recess forming part of a fluid flow passage, and the recess is machined into the respective surface by a material removing tool. This simplifies the making of the casing and enables the latter to optimally conform to the conditions of flow between the supply conduit and the impeller or first impeller of the machine to thus reduce noise and stray movements and enhance the efficiency of the machine.

Abstract: A fluid flow machine, particularly a centrifugal pump, wherein the casing has a tubular first portion serving to convey a stream of fluid radially toward a pump shaft which drives one or more impellers. The casing has a second portion with an arcuate band-like wall which spacedly surrounds the shaft and defines a passage having an oval cross-sectional outline and receiving fluid from the outlet of the first portion. A cylindrical outlet of the passage is adjacent the foremost impeller or the only impeller of the pump. One or more guides are provided in the passage to control the flow of fluid from the outlet of the first portion of the casing toward and into the range of the foremost impeller.