Syphoning effect on pipework 1

[ER_Azza]

Hi All

We had recently changed our pump (for our effluent system) from a screw pump (BLUE PUMP) to an air operated diaphragm pump. Simple setup.

When we stop the diaphragm pump, the discharge pipe maintain its syphoning effect and still pull the effluent from the suction side (due to the level in Pit 2 and RED PUMP running). We do not want to drain the effluent in Pit 1 to dry.

Most simplest option is to drill a hole (or installed a vent) at X, inside pit 2 but way above the bottom of the first pump discharge.

What's your thought?

 

[LittleInch]

Just place a vacuum valve at the top of the loop downstream the blue pump which will stop the syphon.

It's basically nothing more than a spring loaded non return valve.

I don't think your idea would work as its too far away from the peak negative pressure in the syphon

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[goutam_freelance]

Vacuum breaker valve at pump level should work but you also need a foot valve at bottom of pump inlet pipe otherwise you may lose pump priming.A small priming tank at pump level may also be needed to take care of leakage thru the foot valve.

Engineers, think what we have done to the environment !

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[LittleInch]

A foot valve or non return valve would help, but given the blue pump is a diaphragm pump it should be self priming, especially if the lift is quite low.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Just cut off some of the inlet pipe so it does not reach below your minimum level mark.

 

[bimr]

You can also use a full port solenoid valve in the pipe. If the system is automatic, connect the solenoid valve so that it operates when the air pump is operating.

 

[ER_Azza]

Thanks all for the quick feedback.

Will the arrangement below work using a Vacuum breaker?

 

[HTURKAK]

Agreed.. pink star for this simple but neat, working solution..

 

[bimr]

As long as you don't mind getting sewage sprayed on your face as you walk by. You mentioned "effluent system" which indicates that this is a sewage application. Vacuum breakers are not recommended on sewage because of the potential for failure from clogging.

 

[goutam_freelance]

If you cut the pipe the outlet end may be above the downstream tank level (possibility). If it happens the pipe may become empty due to back flow. It is doubtful whether the pump cam pump out air to create vacuum for priming(it is only an assumption).

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/

 

[katmar]

Just put a full bore ball valve in the line and wire it so that it opens when the pump is running and closes when the pump stops.

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[LittleInch]

searching for "sewage vacuum valve" seems to show the valve vendors do specific version for waste water. e.g.

https://www.valmatic.com/Portals/0/brochures/Air_1500.pdf

page 6

Now how good they are in practice is another matter, but at least they are simple and need no power.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[TiCl4]

Cutting off the inlet pipe short will only work if the pipe siphon flow is not high enough to fill the discharge pipe, allowing air back up. If the piping has a sufficient drop between the two levels, that idea may not help at all.

 

[1503-44]

So the water just jumps up into the higher inlet???

 

[LittleInch]

Just depends if ER Azza wants flow to stop when the pump stops or just doesn't want pit A to empty.

Of course if you cut the pipe off you will want a second pipe and valves etc to go to the bottom so that if you want to you can pump out the first pit...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Good idea. You could prime it easier too.

 

[TiCl4]

1503-44,

My apologies, I misunderstood which pipe you were referring to. I thought your were suggesting that for the piping going from the pump to the second tank, which is technically the inlet feed to the second tank, not the pump suction line.

I'll leave my previous post so the conversation train still makes sense.

 

[1503-44]

No worries.

 

[ER_Azza]

HI all,

Thanks again for the feedback.
The vacuum breaker I had in mind is the a simple one.

https://pressuresystems.com.au/product/ps-series-a196-stainless-steel-anti-siphon-vacuum-breaker/

 

[1503-44]

Bimr said "Vacuum breakers are not recommended for sewage."
I tend to believe what bimr says.