Water ring pumps

Water vapor is frequently removed by pumps that operate with water or steam as a pump fluid, for example, water ring pumps or steam ejector pumps. This depends considerably on circumstances, however, because the economy of steam ejector pumps at tow pressures is generally far inferior to that of rotary pumps. For pumping a vapor - gas mixture in which the vapor portion is large but the air portion is small, the vapor can be pumped by condensers and the permanent gases, by relatively small gas ballast pumps (see Section 2.1.5). 

Instead of rotary pumps, large water jet, steam ejector, or water ring pumps can be used. For batch evacuation, and the production of hydrocarbon-free fore vacuum for sputter-ion pumps, adsorption pumps (see Section 2.1.8.1) are suitable. If the use of oil-sealed rotary vane pumps cannot be avoided, basically two-stage rotary vane pumps should be used. The small amount of oil vapor that backstreams out of the Inlet ports of these pumps can be almost completely removed by a sorption trap (see Section 2.1.4) Inserted In the pumping line. 

After the cleaning process has been completed, the jet rods are emptied automatically. The water ring pump is used for drying when the cycle has completed. 

Use of a drying device for the filter housing - a water ring pump, for example - for optimum drying of the housing after a steam sterilization process. 

A modern autoclave is generally equipped with a water-ring pump that can produce a vacuum of approximately 70 residual mbar in the chamber. Accordingly, almost 7% of the air is not removed. The following two methods are essentially used for completing air removal. 

Vacuum pumps are generally divided into 13 categories according to the working principle, as listed in Table 2.5. They include water jet pump, water ring pump, steam ejector, oil-sealed rotaiy pump, Roots pump, vacuum diffusion pump, oil vapom booster pump, sputtering-ion pump, radial field pump, titanium sublimation pump, sorption pump, molecular pump and cryopump [9],... 

Coarse vacuum 1000 to 50 mbar water ring pumps... 

Figure 20 Principle of a venting filter for in situ integrity tests. The integrity tests are carried out following the water intrusion method 1, primary filter with an 0.22 pm cartridge 2, secondary filter with an 0.22 pm cartridge installed as a backup filter, sterilized independently of the filter 1 3, test liquid reservoir (WFI) with heater 4, inlet valve for test liquid (WFI) 5, pure steam inlet 6, filtered air (5 bar absolute) 7, venting gas (1060 mbar) 8, drain line with valves 9, to water ring pump (WRP) 10, to condenser 11, to chamber 12, sanitary valves 13, temperature sensors.

LRVPs are still frequently used to be called water ring pumps, even though they have been used in the chemical industry since the start of the last century. In this sector, they are not only used for creating vacuum but also used as reactors, absorbers, condensers and washers. Process liquids are being used ever more frequently to achieve higher product qualities and pure products. 

The most frequently utilised type of vacuum pump in these areas of application - even since the broad utilisation mechanical vacuum pumps - was and still is today in the area of industrial chemical process engineering, the so-called water ring pump or liquid ring vacuum pump. This type of vacuum pump is covered in-depth in chapter 3 of this book. 

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