priming tank design

[majdesigner]

I want to attach a priming tank to an existing set of pumps. the pumps take suction from an underground tank with suction lines having foot valve, thus normally pumps remain primed. I understand that generally a tank having 3 times the volume of suction line is used. But once I start the pump it will suck all the water from the P tank, IS THERE SOME WAY TO ENSURE THAT PUMP TAKS WATER FROM PRIMING TANK ONLY IF THE SUCTION LINE NEEDS TO BE PRIMED??

 

[BigInch]

Fill your prime volume, start and begin turning off the Ptank valve.

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"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

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[BigInch]

Forgot this link which might help with some valve ideas. Maybe your foot valve leaks.

http://www.gouldspumps.com/pag_0029.html

"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.

"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

 

[Artisi]

Anything and everything is possible, it just needs design and money.
Do you want /need an auto system of can it be done manually?

For interest, what size pump units are you talking about?

 

[majdesigner]

Thank you both for responding. The pumps I am dealing in are 500 gpm 7 bar with 4 inch suction side. they are supposed to run on auto but the foot valve develops leakage and pump runs dry. I need a cheaper solution (no sensors and alarms please)

 

[Artisi]

Fit a priming tank to each unit then you needn't worry about it being pumped dry by another pump.

 

[BigInch]

Use a float valve connected to a sluice gate valve with a lever. Arrange it so that when float drops to lowest allowable level the lever will close the valve.

 

[majdesigner]

thanks BigInch, will try it
thanks Artsi for contributing

 

[katmar]

majdesigner, I have worked with priming tanks based on your "3x volume" rule and they work well. The line from the sump should enter the top of the priming pot. Use a 180 deg bend on top of the tank and go straight down into the sump. In this way, if your foot valve leaks and air is drawn into the system only the pipe from the tank down to the surface of the sump can drain out. The 3x volume remaining in the tank will enable the pump to re-start and draw the water up the suction line. Entering from the top ensures that there is good turbulence in the tank and with time any air in the tank will be entrained in with the liquid and pumped out - leaving the tank full of liquid for the next time it starts.

Katmar Software
Engineering & Risk Analysis Software

http://katmarsoftware.com

 

[chicopee]

About having check valves so that water is always available in the lines and forgo the priming.