Valve for gravity-fed watering system

The example projects I've found all use a pump and solenoid that requires at least 20 kPa. Can anyone recommend a valve suitable for building a small gravity-fed watering system?

There are loads of motorised valves and solenoids but they depend on if the project is using a relay for ac, is battery powered etc etc. You cant really recommend a valve without a basic idea of the application.

I was thinking of just using a 5V USB power supply plugged straight into a wall socket and a 5V-to-12V DC-DC converter to control the valve, if possible.

If the valve needs AC though, using a relay is just fine by me. Whatever is simpler.

type 12v motorised valve into google and you will get lots. if you don’t mind ac then there are even more

here is a no-pressure washing machine drain valve that might work.

Soft wall tube.
Solenoid
Bend to kink

Soft wall tube
Solenoid
Cam
Rotate cam to squeeze
#######
Periostalic pump
Remove all but one roller
Rotate to seal
Rotate to allow to flow.

peristaltic

Do not look for a standard solenoid valve. Look for a "piloted" solenoid valve. They switch by using the pressure of the water to move a diaphragm which opens and closes the main valve. Minimum pressure difference will let the valve operate.

Paul

alto777:
peristaltic

Danm... now i gotta rewrite all my code....

This one claims to work at 0 PSI:

Why not forget the electrics and use a basic float valve.

float-valve.jpg

float-valve.jpg

bluejets:
Why not forget the electrics and use a basic float valve.

float-valve.jpg

I have one of those! I have no idea where or why I have it. All brass. 3/4 pipe inlet.

Paul

Paul_KD7HB:
I have one of those! I have no idea where or why I have it. All brass. 3/4 pipe inlet.

You see it many times a day in the smallest room of the house!

Small Gravity water system.

You can get a small pump. About a dollar.
5 volt. Simple and very cheap
Ues a tee at the top of the bucket to break tthe Siphon.

Small inexpensive motorized valves are hard to find.
Low cost solenoid valves tthat Work with low pressure are also hard to find.

Let us know what you choose and how it works

AJLElectronics:
You see it many times a day in the smallest room of the house!

Yes, but not of the same physical design. Mine and the one pictured are for cattle water.

Paul

https://www.aliexpress.com/item/33035325360.html

Would one of these work? You're right Dave, cheaper than any valve I've come across