Vacuum Release for Pump Shutdown

[cthor64]

We have system that uses a vacuum pump that generates around 10" hg of vacuum. When the system is shutdown the pump runs backwards at a really high rpm to as the air enters the system through the pump. In order to extend the life of our pump I want to add a pressure relief to allow the system to equalize with the atomosphere. I'm thinking of a solenoid valve so that when the pump is on it is closed and when the pump is off it opens. Does anyone have experience with such a system? What type of valves or controls have been used?

Thanks,
Carl

 

[BigInch]

Why not a solenoid valve at the pump's discharge?

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[BigInch]

BTW that's in the discharge pipe, not open to atmosphere. Just close that valve when the pump stops.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[cthor64]

Biginch, thanks for the quick response. I think that would be a good way to do it. However, the pump discharges to a 6" pipe. I was looking to vent to atmosphere because there is already an unused (plugged) 2" tap on the discharge pipe.

 

[BigInch]

Oh. OK. I didn't know it was so small.

Or just a check valve in the discharge might do well too, if you don't need totally positive shutoff.

If you vent to atmos on the pump discharge side, or on pipe discharge side, that won't work. Remember you have a vacuum in the pipe, so you're "venting" to a source which will probably just hasten the backflow through the pump.

You'd have to "vent" the suction line, but then you lose any vacuum you have there which only must be pumped out again on startup. Waste of effort and energy.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/