| abstract |
A motor pump unit (1) (fig 1) has for protection against highly corrosive conveying media in the region of the pump (2) an inner covering of polytetrafluoroethylene (PTFE). In the case of the motor, different corrosion-resistant materials are used, matched to the different requirements for on the one hand the can (10) and on the other hand for the rotor (9). The can (10) expediently consists of PTFE with a filler content of 10 to 15 % carbon graphite. This produces not only the resistance to corrosive media but also a high mechanical stability and a good thermal conductivity. The rotor (9) with shaft has an enamel casing (11), which has a sufficiently good thermal conductivity and also allows the surface of the rotor to be produced with high fitting and dimensional accuracy. In addition, favourable temperature expansion characteristics are obtained. The application of a continuous impervious enamel layer is assisted by using a solid-iron rotor. In the region of the end windings (21), a casting compound is introduced, preferably of epoxy resin with quartz flour as filler to improve the thermal conductivity and for mechanical support of the can. The bearings are designed as corrosion-resistant sliding bearings. <IMAGE> |