Axial Check valve installed as a foot valve
Axial Check valve installed as a foot valve
(OP)
Hi,
An axial foot check valve is installed in the vertical position in a sump.
The height difference between the (pump suction flange) and the (foot valve location) is 3m.
The issue is that the foot valve is leaking (not fully closing)to allow to prime the pump and hence it is not possible to pump water from the sump.
The manufacturer manual of the axial check valve states that 5m WC is required for tight closure of the axial check valve in vertical position.
Can we install the foot valve horizontally using a 90 degree bend, so as to make the same axial valve work as a foot valve (with tight closure)?
Do you see any other way to make the scheme work without changing the foot valve?
Thanks
An axial foot check valve is installed in the vertical position in a sump.
The height difference between the (pump suction flange) and the (foot valve location) is 3m.
The issue is that the foot valve is leaking (not fully closing)to allow to prime the pump and hence it is not possible to pump water from the sump.
The manufacturer manual of the axial check valve states that 5m WC is required for tight closure of the axial check valve in vertical position.
Can we install the foot valve horizontally using a 90 degree bend, so as to make the same axial valve work as a foot valve (with tight closure)?
Do you see any other way to make the scheme work without changing the foot valve?
Thanks





RE: Axial Check valve installed as a foot valve
I think you'll need a vacuum pump to prime the suction, or move the pump down toward the bottom of the sump.
Mike Halloran
Pembroke Pines, FL, USA
RE: Axial Check valve installed as a foot valve
You could install two in series?, install a self priming pump or add a vacuum line to the inlet of the pump to proved the flooded inlet or try a different type of foot valve, aka Non return valve or install a submersible pump.
No other details so can't really go much further....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Axial Check valve installed as a foot valve
RE: Axial Check valve installed as a foot valve
RE: Axial Check valve installed as a foot valve
RE: Axial Check valve installed as a foot valve
a) Reverse flow of air through the discharge line if there is no discharge SDV
b) Reverse flow of air through pump shaft seals - for single seal configuration
c) Some other reverse flow location.
See if you can cut out these reverse flow sources, where applicable.
RE: Axial Check valve installed as a foot valve
RE: Axial Check valve installed as a foot valve
Mike and Littleinch, you guys are right, it does not make a difference if I put in a bend.
compositepro, I don't completely agree with that, because the head available above the foot valve outlet flange, is equal to the length of the pipe below the flange of the pump suction flange, irrespective of the level of water in sump. Please explain to me if you think differently.
Georgeverghese, Interesting way of opering an axial foot valve with air assistance- do you have an example?
Regarding the issue at hand,
I discussed with the manufacturer regarding the issue, and they informed me that the check valve is designed to close reliably at 5m and not 3m in vertical condition.
I suggested a change of spring to facilitate closure of the foot valve at 3m, but apparently tolerances, coating thickness and other features also need to be controlled to ensure that the foot valve will reliably close at 3m.
Thankfully the manufacturer agreed to send the axial foot valve tested for 3m.
Thank you for your comments.
RE: Axial Check valve installed as a foot valve
I just re-read your original post and I wonder why you think mounting the check-valve horizontally would help. In almost all valve designs the ball or flapper weight will help seal the valve in the vertical position, which is what you want.
RE: Axial Check valve installed as a foot valve