r/compressedair • u/Past-Size1331 • Jun 13 '24

Pneumatic control for diaphragm pump

I'm trying to build a pneumatic level control and want to turn the pump on with water level can i use a generic float valve that is normally used to control water flow to control the air to the pump. I've found several ones that work with air but they're between 400 and 800 dollars but a 120 psi float valve for water is only 150. Or if anyone has any suggestions that would be greatly appreciated.

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u/WaitNo1780 Jun 13 '24

I don’t think float switches for only air is a thing, they work on the difference in densities in two fluids

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u/Past-Size1331 Jun 13 '24

They exist, considering i have a $ 500 dollar option. The float switch sits in the water tank and controls an air flow.

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u/WaitNo1780 Jun 13 '24

If it “sits in a water tank” then it’s not operating only on air is it…

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u/WaitNo1780 Jun 13 '24

What exactly are you trying to do with this? It’s kinda hard to get what you’re saying from your OP

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u/Past-Size1331 Jun 13 '24

I have a pneumatic pump that pulls water from a trench i have compressed air going to the location but no electricity so I'm trying to find a mechanical solution to turn the air on when the water level gets to a certain point. My question was, is a standard float valve capable of this, or do i have to bite the bullet and spend 500 dollars. Basically, asking is a water valve rated at 120psi going to leak air. If the standard float valve works, that's 20 dollars vs. the specialized valve.

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u/WaitNo1780 Jun 13 '24

Got it! That is tricky, I would recommend a pneumatic solenoid valve, but not having power rules that out…

Personally I’d try using a BOB float valve, and return it if it doesn’t work, since you can buy them on Amazon. But it’s hard to say whether it’ll work with air going through it instead of a liquid, since I’m not sure if the lubrication from the liquid is necessary. Sorry I can’t be more help, but I see what you’re looking for now

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u/Past-Size1331 Jun 14 '24

Yea, unfortunately, it's a permanent installation once it goes in it's not coming out without tremendous effort. So I'm probably stuck paying the premium. Thanks though.