What liquid expands the most with a temperature change?

[4570Man]

That's pretty much what I'm trying to accomplish but I need it to close at a lower temperature. Since other similar devices exist I might as well spill the beans since I'm not going to get rich. I'm trying to activate a water shutoff valve when it gets below freezing. I'm hoping to use no electric before most of the other versions do use electric and I'm hoping that with spring assistance it will turn the water back on when it warms up.

 

[davedj1]

Use water then. It expands when frozen and will contract at room temp from frozen size. Make your own cylinder out of some plastic pipe. Test random sizes, I would start small diameter so it would freeze before valve. Like tow sizes of pex ? Or maybe even a rubber diaphragm with some sort of gas in it? You could pull the valve instead of push it?

 

[countrybumpkin]

May do some searching in this area, you might get some more ideas.

Pages - Typical Self-acting Temperature Control Valves and Systems

 

[4570Man]

Use water then. It expands when frozen and will contract at room temp from frozen size. Make your own cylinder out of some plastic pipe. Test random sizes, I would start small diameter so it would freeze before valve. Like tow sizes of pex ? Or maybe even a rubber diaphragm with some sort of gas in it? You could pull the valve instead of push it?

By that point my water lines are already frozen.

 

[Renze]

Salt expands quite extreme, but it turns liquid only after 450 degrees Celsius or so.

What do you need it for, a Stirling engine ?

 

[Tractor Seabee]

Greenhouse vent cylinders.

From:
Automatic Greenhouse Vent Openers & Circulation Fans

How automatic vent openers work: Vent openers do not require electricity. The opener has a metal cylinder containing a mineral which expands when heated. This pushes a piston that opens the vent. As the temperature cools, the mineral shrinks and a spring closes the vent and resets the piston. The opening and closing of the vent is gradual allowing just the right amount of air flow for cooling.

and

From:
Greenhouse Accessories : Univent Automatic Vent Opener Replacement Cylinder

Use the Standard Vent Opener to lift up to 15 lbs, and the much stronger Gigavent, with powder-coated green, all metal construction, to lift up to 65 lbs.


Bruce

They also use a linkage that multiplies a small movement into a longer stroke. There is an engineering principle there.

Ron

 

[Tractor Seabee]

That's pretty much what I'm trying to accomplish but I need it to close at a lower temperature. Since other similar devices exist I might as well spill the beans since I'm not going to get rich. I'm trying to activate a water shutoff valve when it gets below freezing. I'm hoping to use no electric before most of the other versions do use electric and I'm hoping that with spring assistance it will turn the water back on when it warms up.

Quarter turn water valves take more pressure than you may realize so size your cylinder commensurate with that issue.

Ron

 

[4570Man]

Quarter turn water valves take more pressure than you may realize so size your cylinder commensurate with that issue.

Ron

I actually need to turn off a frost free hydrant because it's the only water source I have and it'll freeze if it's open.

 

[Tractor Seabee]

I actually need to turn off a frost free hydrant because it's the only water source I have and it'll freeze if it's open.

They take more power to open and close. This project may turn into something more trouble than it's worth.

Ron

 

[4570Man]

They take more power to open and close. This project may turn into something more trouble than it's worth.

Ron

Likely so but I enjoy a challenge. After I posted this thread I've found a valve that Ts into the water line and opens once the water reaches 35 degrees. That solves 2 possible 3 of the 4 hurdles in this project. The next issue is if I use that approach how do I turn the water back on?