Vaccum pump calculation

One of the things is the vapour pressure of the process fluids at the operating temperature. At that pressure, liquid will boil, preventing any further reduction in pressure until all the liquid has turned to gas.

So, process conditions are always involved.

Definitly need to know what the entire system looks like from process to pump. Need to consider level of vacuum needs at the processes, vacuum losses in the length of piping from the process to the pump, potential leak points, etc.

Calculations on Liquid ring/piston vacuum pump is complicated process.

Majority of shaft energy goes for maintaining the liquid ring and circulation.

Thius is unlike a reciprocating machine, wherein the geometry is simple to calculate. Swept, clearance volume etc are easier to conceive and calculate.

Where as in Liquid ring/piston vacuum pump, the total volume for calculation is not simply the air volume of the rotor.

It is the volume of gas space between two consecutive vanes -volume of liquid in the same space when these vanes are at major diameter.

If this volume is: 'V' then,

The total Volume per minute = V * No compartments * rpm