Backressure automatic control valve

[needmoremaples]

Does something like this exist? It's basically a pressure relief valve I think but it's meant to be controlling back pressure and not popping off in case of over pressure.

I think most RO throttle the back pressure with a needle valve and slowly back it off in a recirculation type setup. I would like to maintain 220 psi and it be potable water/food grade. Ideally 3/4 threaded but I can make it work whatever you find. Lmk if you know of one.

[Tweegs]

This is close:
https://www.zoro.com/watts-pressure-regulator-12-in-100-to-300-psi-12-ss-263a-e-100-300/i/G0274723/

Reading your post, I get the impression you want to auto-regulate membrane pressure in an RO.
If that’s the case, I don’t recommend this approach.

[fred]

buy a food grade gate type valve. put it on the exit side of the membrane- permeate line. there has to be a electronic shut off when pressure is too high. those can be bought at any dealer or electric shop, wire to pressure pump

[needmoremaples]

Yep that's what I'm trying to do tweegs. I'm almost tempted to try and make one. All it is, is a higher spring pressure in a spring loaded check valve. Find the right spring and you are golden.

Fred- I'm confused and also intrigued to what you are saying. Why the permeate line?

[fred]

Why the permeate line?

that how the bigger units work. more pressure to the vessel with restriction to the permeate line forces the sugars out. the water comes out the center top, concentrate to the outside

[Super Sapper]

Restricting the permeate side would allow all the sap to run around the outside of the membrane and no permeate would be produced. If you restricted both you are just hindering the unit as you would drop the pressure differential across the membrane and thus push less water through.

[iby]

here's a much cheaper version

https://www.tractorsupply.com/tsc/product/hamilton-pressure-regulating-bypass-valve-nylon-3-4-in-mnpt-inlet-x-3-4-in-fnpt?cm_vc=-10005

I have used this in the past with some success..

[needmoremaples]

That's what I'm looking for!! Thanks dude!


here's a much cheaper version

https://www.tractorsupply.com/tsc/product/hamilton-pressure-regulating-bypass-valve-nylon-3-4-in-mnpt-inlet-x-3-4-in-fnpt?cm_vc=-10005

I have used this in the past with some success..

[needmoremaples]

Restricting the permeate side would allow all the sap to run around the outside of the membrane and no permeate would be produced. If you restricted both you are just hindering the unit as you would drop the pressure differential across the membrane and thus push less water through.

I think we are baffled together. He had to have meant the opposite.

[johnallin]

I think we are baffled together. He had to have meant the opposite.

Pretty sure Fred knows a "little bit" more about RO's than you think he does.

[wmick]

Does something like this exist? It's basically a pressure relief valve I think but it's meant to be controlling back pressure and not popping off in case of over pressure.

I think most RO throttle the back pressure with a needle valve and slowly back it off in a recirculation type setup. I would like to maintain 220 psi and it be potable water/food grade. Ideally 3/4 threaded but I can make it work whatever you find. Lmk if you know of one.

I'm curious but not quite following.. Are you planning to put this bypass valve in the outgoing concentrate line (instead of a needle valve), or in the line between your pressure pump and the membrane??

[bowhunter]

Absolutely do not put back pressure on the permeate line. You can destroy your membrane. A number of people on this forum have over pressured the permeate side when they made a mistake on the plumbing. In any case the higher the permeate pressure the lower the permeation rate. You would be defeating the purpose of the RO.

[needmoremaples]

talked to a smart fella yesterday and he said a centrifugal pump cant over pressurize a membrane to the point of explosion because centrifugal pumps will just slip in that scenario. In my head i thought it could but i started out knowing that could happen when using a aquatec diaphragm pump on the little membranes. i ordered the TSC valve above also. I guess i will wait a month and see what happens.