| 摘要 |
The pump has a housing 7 accommodating a plurality of rotors 1, 2 at least one of which is made of a non-metallic material having a smaller coefficient of thermal expansion than the material of which the housing is made so as to reduce friction between the rotors and/or the rotors and the housing. The non-metallic material may be a plastics one with a fibre filling or an electrically conducting filling e.g. carbon, to provide a leakage path for electrostatic charges. The housing, too, may be made of a non-metallic material. The working fluid may be a hydrocarbon fluid or steam. <IMAGE> |
