Ring Pumps

A big part of the overall problem with adequate mechanical. seal life is trying to make a precision mechanical seal run into the same. space that previously was occupied by the packing rings. Pump design evolved over time to accommodate the packing rings. 

Figure 6-9C. Improving the maximum vacuum obtainabie by staging an ejector ahead of the suction of a iiquid ring pump or any other device that can handie water into the unit, uniess dry air is used. By permission, Graham Manufacturing Co., Inc.

Figure 6-110. Typical performance curves for steam jet ejectors, liquid ring pumps, and rotary piston oil-sealed pumps. By permission, Ryans, J. L. and Roper, D. L. [24],...

Vacuum capacities and operating ranges, table, 344, 355 Ejectors, 344, 357 Integrated systems, 344 Liquid ring pumps, 344 Rotary lobe blowers, 344 Rotary piston pumps, 344 Rotary vane pumps, 344 Vacuum equipment, 343 Applications diagram, 352 ASME Code, 344 Pumps, 382 Steam jets, 357 Vacuum flow,... 

Friction losses, air steam, 131 Pressure losses chart, 134 Vacuum pumps, mechanical, 382 Liquid ring pumps, 383-385 Liquid ring volume displaced/ evacuation, 387... 

Figure 8.36. Nash Hytor liquid ring pump...

Introducing local recycles around liquid 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. 

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