Liquid jet vacuum pumps with threaded connections are mainly used in chemical laboratories for the production of vacuum, for example in vacuum distillation or drying.

They are also used for evacuating syphon lines, suction lines of circulating pumps and condensers; for deaeration of pressure vessels and for producing negative pressure in Nutsch filters.

Liquid jet vacuum pumps, when water is used as the motive medium, can be directly coupled to the water line. If, however, the water consumption has to be as economical as possible, the operating water may be circulated. This is also the case when other liquids are used as the motive medium, instead of water.

The temperature of the operating liquid may be kept low by the constant addition of a small quantity of fresh liquid. Higher vacuum can be achieved by further cooling of the operating liquid. This is particularly expedient when the suction flow contains condensable components, e.g. solvents. In such a case the vacuum pump can be operated by using the condensate as the motive medium.

The lowest suction pressure which can be obtained with a suction capacity of zero (blind vacuum) corresponds to the vapor pressure of the motive liquid which depends on the temperature of the liquid.

The action of liquid jet pumps is based on the fact that the liquid jet coming out of the motive nozzle at high speed entrains air, gas, liquid or solid matters from the head of the jet pumps and compresses them to atmospheric pressure.

For more detailed information on structure and mode of operation of jet pumps please refer to “Product catalogue”.