Liquid ring vacuum pump control
Liquid ring vacuum pump control
(OP)
I am trying to find the correct method for determining how much air should be added to the suction of a vacuum pump to control the suction pressure at a specified value within the design range of the vacuum pump. My previous attempts at determining the air flow have not been accurate enough, so I am hoping someone else can shed some light on the correct approach.





RE: Liquid ring vacuum pump control
The way to do it is to put a valve in the bleed line and let it control the suction pressure of the pump. If you do it this way the flow information you read off the pump curve should be plenty accurate enough for you to size the pipe and control valve. Where did you go wrong previously.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Liquid ring vacuum pump control
RE: Liquid ring vacuum pump control
RE: Liquid ring vacuum pump control
I would size the bleed valve to give the full rated volumetric capacity of the pump at the desired suction pressure so that it could cope in the situation where no air is coming from the process. If you need less air than this the valve can close down. We used to say that a valve should never operate at less than (say) 30% open if we wanted decent control, but with modern controllers I have seen butterfly valves operate absolutely stably at only 10% open. Its best not to design for that, but it can work.
Have you asked your pump supplier for help? Here in South Africa I have found the pump supplier's technical backup to be very good. Hopefully you are in a similar position.
What went wrong in your previous application?
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Liquid ring vacuum pump control
RE: Liquid ring vacuum pump control
Anne Delestre
www.cutes-europe.com