Pump for cryogenic fluid, especially fluid gained during an air distillation process, such as liquid oxygen, has labyrinth seal to prevent contamination of cryogenic fluid by flow of operating fluid from motor to pump impeller

摘要

The pump has a labyrinth seal arrangement(35) to prevent contamination of the cryogenic fluid(3) by flow of operating fluid(15) from the motor to the pump impeller(21). The pump is immersed in the cryogenic fluid to be pumped, and the pressurized operating fluid is supercooled. The hydraulic motor has a drive wheel(13) driven by the operating fluid and seated upon the same shaft(27) upon which is mounted the pump impeller. The shaft is seated in bearings(29,31) lubricated by the operating fluid. Independent claims are also included for the following: (a) a use for the pump, which is in an air distillation plant; (b) a pump unit with two pumps; (c) a plant for air distillation, incorporating the proposed pump.