Obtain product and technical data sheets from the manufacturer selling you the liguid ring pump.
Vacuum flow rate from the point of pickup can be a tricky thing if you are in a manufacturing environment with long distance from the pump to the point a vacuum is used. If any appreciable distance is involved, you will need to factor in one or two increases in pipe size to minimize vacuum loss in the distance traveled.
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Eventually, one needs to realize that it is far less important to be the smartest person in the room than it is to sit next to that person and make friends.