Contributions to an ultra-high temperature (250°C/500°F) bearingless pump

The semiconductor industry demands for pumps which handle aggressive fluids at very high temperatures, as this is an important step towards higher process speeds and increased yield in semiconductor etching applications. This paper presents the thermal, electrical and mechanical design of a bearingless pump for operating temperatures of up to 250 °C without active cooling. A detailed thermal analysis of the machine is presented which allows for the prediction of the thermal stress of critical components. The machine design is based on the prediction of the internal temperatures and hydraulic specifications of the pump. Furthermore, a hallsensorless, observer-based, control of the rotor angle is presented. The necessity for this control scheme arises from the high temperatures that prevent the usage of conventional angle measurement systems.