Abstract: A connected impeller and shaft is provided. The shaft has a first part which provides a threaded portion carrying a thread which screws onto a corresponding threaded portion of the impeller. The shaft also has a second part which provides an abutment surface for engaging a corresponding abutment surface of the impeller when the threaded portions are screwed together, thereby tightening the threads to provide a rotationally fixed connection between the impeller and the shaft. The first part is rotationally fixed relative to the second part at a joint. The threaded portion of the shaft is axially spaced a first distance from the abutment surface of the shaft. The threaded portion of the shaft is axially spaced from the joint by a second distance which is greater than the first distance. The threaded portion of the shaft and the joint are on the same side of the impeller.

Abstract: A connected impeller and shaft is provided. The shaft has a first part which provides a threaded portion carrying a thread which screws onto a corresponding threaded portion of the impeller. The shaft also has a second part which provides an abutment surface for engaging a corresponding abutment surface of the impeller when the threaded portions are screwed together, thereby tightening the threads to provide a rotationally fixed connection between the impeller and the shaft. The first part is rotationally fixed relative to the second part at a joint. The threaded portion of the shaft is axially spaced a first distance from the abutment surface of the shaft. The threaded portion of the shaft is axially spaced from the joint by a second distance which is greater than the first distance. The threaded portion of the shaft and the joint are on the same side of the impeller.

Abstract: A connector for connecting an impeller to a shaft is provided. The connector is formed as a unitary body. The connector has a sleeve portion which is frictionally connected on a radially outer surface of a shaft-side hub extension of the impeller. The connector further has a threaded portion carrying a thread which screws onto a corresponding threaded portion of the shaft, such that the connector provides a rotationally fixed connection between the impeller and the shaft. The hub extension has a central recess, and a part of the connector is inserted into the recess. The frictional connection between the sleeve portion and the radially outer surface of the hub extension transmits, in use, substantially all of the torque between the shaft and the impeller.

Abstract: A connector for connecting an impeller to a shaft is provided. The impeller has a shaft-side hub extension with a central recess. The impeller is formed of a material having a greater coefficient of thermal expansion than the material of the shaft. The connector is inserted into the recess to frictionally connect an outwardly facing surface of the connector with a radially inner surface of the hub extension. The connector has a threaded portion carrying a thread which screws onto a corresponding threaded portion of the shaft, such that the connector provides a rotationally fixed connection between the impeller and the shaft. The connector is formed of a material having a coefficient of thermal expansion which is greater than the coefficient of thermal expansion of the material of the shaft.

Abstract: A connector for connecting an impeller to a shaft is provided. The connector is formed as a unitary body. The connector has a sleeve portion which is frictionally connected on a radially outer surface of a shaft-side hub extension of the impeller. The connector further has a threaded portion carrying a thread which screws onto a corresponding threaded portion of the shaft, such that the connector provides a rotationally fixed connection between the impeller and the shaft. The hub extension has a central recess, and a part of the connector is inserted into the recess. The frictional connection between the sleeve portion and the radially outer surface of the hub extension transmits, in use, substantially all of the torque between the shaft and the impeller.