Liquid piston vacuum pump

Liquid-piston vacuum pump down to 12 kPa absolute 0.01 to 1000 kg/h air see also Section 6.37. 

Liquid piston vacuum pump cool seals with 0.03 L/s of clean cooling water at pressure at least 35 kPa greater than discharge pressure of pump. 

But the liquid ting pump has (1) multiple vanes (fins) vs. a single one (often) for the rotary vane pump (2) no vanes which contact the perimeter of the cavity as it s essential for aU to do so in a rotary vane pump (3) a point of entry for the vapor within the rotor and not at the circumference of the casing as is typical of other vacuum pumps and (4) a "pool" of liquid which acts a "collector" to remove vapor from the work chamher and also as a piston to compress the vapor not a good descriptive diagram of a liquid ring vacuum pump is shown in Figure 2.9. 

Positive displacement pumps diaphragm vacuum pumps, liquid ring vacuum pumps, rotary vane and rotary piston vacuum pumps as well as Roots vacuum pumps (dry compressing claw and screw pumps are not yet mentioned here but also belong to this group of pumps). 

It is to be taken into account that with the employment of rotary piston vacuum pumps, the temperature of the fluid fed to the liquid ring compressor is higher than with the other combinations. In addition, this heat is to be dissipated by the ring liquid, so that the temperature of the liquid ring will be higher and with it the suction capacity will be lower. 

Vacuum breaker, 291 Vacuum pump, 9 Vacuum service, 10 ejectors in, 11 liquid pi.ston, 9 liquid piston, 130 sliding vane, 10 Valve design, 62 Valve loss, reciprocating, 62 Valve unloader, 81 Valve velocity, 62 Valves... 

The most used mechanical vacuum pumps or compressors are reciprocating, liquid-ring, rotary-vane, rotary blower, rotary piston, and diaphragm. 

The Nash vacuum pump or compressor has only one moving part—a balanced rotor that runs without any internal lubrication. Such simplicity is possible because all functions of mechanical pistons or vanes are performed by a rotating band of liquid compressant. 

Liquid-Piston Type This type is illustrated in Fig. 10-97. These compressors are offered as single-stage units for pressure differentials up to about 0.52 MPa (75 Ibf/in ) in the smaller sizes and capacities up to 6.8 X 10 mVh (4000 fF/min) when used with a lower pressure differential. Staging is employed for higher pressure differentials. These units have found wide application as vacuum pumps on wet-vacuum service. Inlet and discharge ports are located in the impeller hub. As the vaned impeller rotates, centrifugal force drives the sealing liquid... 

Phases Gas-liquid fast reaction when the upstream equipment operates under a vacuum. The liquid piston draws the vacuum with the vapor reacting with the liquid sealing the pump. 

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,... 

Figure 8 gives details of the piston injectors and vapour pressure cell. Only one of the injectors is shown. The piston injector is a commercial 100 cm capacity liquid metering pump capable of operating under vacuum conditions. The displacement volumes can be read to 0.01 cm . The vapour-pressure cell consists of a 100 cm glass vessel connected to a metal lid E by an O-ring seal. The lid supports a magnetic stirrer, a set of baffles, and an evacuation port H. 

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