In a vacuum pump, does the inlet pressure measure closer to 30 inHG?
The following is a pure water pump, a 100w 8 meter regenerative turbine pump. Not a vacuum pump. Maybe the reason it couldnt get lower than 20 inHG was because its not a vacuum pump? Or is the analysis the same in both? How low can a real vacuum pump measure in the suction side?
I wanted to understand the physics side of vacuum in pumps, so I bought a compound pressure gauge that can measure absolute zero to atmospheric pressure and positive pressure.
I throttled the ball gate valve to decrease atmospheric pressure in the inlet of a 100W Regenerative turbine pump.
But the most I could measure is -20 inHG. I can't get to -30 inHH or absolute zero. Will it work if I move the pressure gauge closer to the impeller? But as I understand, vacuum is uniform in enclosed space, or does it vary in different portions inside? I can't find any adaptor that can make the gauge closer to the impeller. I have to let fabricator design one and it will be expensive and will take long.
If I used a centrifugal pump, will the vacuum be absolute zero close to the impeller? I assume the eye of the impeller is absolute zero vacuum? how large does the vacuum extend and how do you compute it (if you know how)?