What type of pump can be used for moving liquid in a process under vacuum? I am of need of help in my google kung fu. Instead of using a vacuum rated mechanical seal stirrer I want to use a inline pump to agitate / move water under reduced pressure conditions. The water will be at a boil 50c or so. Gear pumps? Centrifugal? I am having a hard time forming a search to get to the content I need.
No personal experience with this one, but I’ll give it a shot.
Not knowing the volume you are trying to move I would say one of these chugger/ stainless steel pumps.
https://www.google.com/search?q=chugger+pump&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari
i think the internal/shaft seals would have to be good enough to deal with the pressures created by the impeller.
A diaphragm pump could be an option too.
Gear pumps work well for the pressure application, but they often have trouble with low viscosity fluids
Under perfect vacuum the only thing that’s going to move fluid is gravity. So make sure that your pump is below the liquid level, as under vacuum its going to be an uphill battle (literally) to make your pump pull fluid against a vacuum.
From experience peristaltic pumps will move fluid under vacuum but the efficiency is dictated by rotors and rotation speed, less rotors means more GPH/LPH transfer for a given RPM at no vacuum but also means more liquid moving backwards when the pump inlet is under vacuum. I suspect more rotors means more liquid moving forward with minimal backwards movement, but at the cost of flow and 6-8+ rotor peristaltic pumps get stupid expensive when we’re talking about any significant flow. The 3 rotor ones are bad enough when you’re talking about 1/2-3/4"+ ID tubing within the pump body.
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