Solenoid Valve Question

Thanks Rakesh.

I have been looking at washing machine valves, but I've found few manufacturers who offer the threaded ports I need for this application. Still looking though.

This: Advantages of Direct Acting and Pilot Operated Solenoid ... gives a good explaination.

rakesh_semwal gives you very good advice.

Lyn,

Thanks for that link. I'd previously read that and it was definately helpful for background info. But I was more looking for advice as to which might be best for my particular application. This sort of thing isn't my field and I'm flummoxed.

Pilot-operated valves are selected when the power of the solenoid is insufficient to activate the valve; the solenoid operates a pilot valve and the pilot valve directs a portion of the fluid to operate the valve itself. They are typically found in larger valves, and are slower to operate than a direct-acting type.

For a "household sink water line" the differences are not going to be hugely relevant. Just select the type of valve that best suits the pipeline size, and the fluid chemistry, its temperature and pressure.

I'd been guessing that the pilot-operated ones reduced solenoid size / cost since they only have to shift that comperably smaller pin in the control port as opposed to a larger plunger / spring combo pinching off the water supply directly.

"Not hugely relevant" adds up after a few thousand valves though.

That said, can anybody tell me if the direct-acting kind is more resistant to crud in the water line?

_{[Definition of abbreviation: "CRUD" - chemical reaction unidentified deposit.]}

Only in as much as there isn't a pilot port to gum-up with crud in a direct-acting valve.

Why not strain/filter the water upstream; why is the downstream process resistant to line-borne crud if the valve is susceptible? Why not use a different valve that is designed specifically to be used with dirty water?

Unfortunately this is for residential use and from past experience we've learned that the vast majority of customers won't bother to use filtering - even when offered a filter. Regrettably an integrated filter isn't an option.

And I would be absolutely delighted to learn more about a type of valve designed specifically to be used with dirty water!

So, after a game of "20 questions", the forum has established that this equipment is designed to supply non-potable water to households on a thousand-sized scale. Surely it's time to stop wasting time on CR4 and start discussing the valve selection methodology with local valve distributors?

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I appreciate your and the other CR4 members help on this. And yes, I'll be taking it up with local (actually mostly overseas) valve suppliers. I just wanted some good information to go in with so I didn't seem as clueless as I'm happy to admit to being in this forum.

And my apologies if you felt this was a game of 20 questions.

"And I would be absolutely delighted to learn more about a type of valve designed specifically to be used with dirty water!"

It will certainly depend on just what 'dirty water' really means. The valves for lawn sprinkler systems are generally designed to be used with nonpotable water from an open ditch, so they will generally tolerate the occasional chunks of leaf or bug that have been run through a pump and softened/macerated. Easy to source, relatively inexpensive, lots of selection features...

They are generally not intended for many cycles per day (something else the forum has no info about).

Pilot operated valve need a min pressure at its inlet to keep the outlet leak proof when outlet is in closed position. which is not in the case of direct operated. one of the application for pilot operated is washing machine, where you can get enough pressure at its inlet as it is directly connected with the overhead water tank with enough head to keep it close, where as later one is used in coffee vending machine where inlet pressure can go as low as zero in few minutes.

I would think the main difference is line pressure...here's some

http://www.solenoid-valve-info.com/cheap-solenoid-valves.html
Higher quality...
Grainger water valve 1/2"

Dual manual shut off...

I need to instruct using this hydraulic van điện từ. Please, help me find suppliers of this type.

I only use the van điện từ UniD

Pilot operated solenoid valves typically need a minimum pressure differential to operate.

Not all applications have a DP that will operate a pilot valve. Caveat Emptor.

I agree with PWSlack. If you are buying these in quantity, it's time to get someone involved who will have a financial stake in the outcome. He sells you the right valve, at the right price, and he makes money. More valves, more money.

Another economical water solenoid valve is the type used in underground lawn sprinkler systems.

I had similar valves installed in some of restaurants. They had sensors which would sense the hands of customers and automatically operate the valves. They worked for some years but disappeared after some years, may be due to faulty operation.

For your application direct-acting is economical. Pilot-operated is better for big size valves. It has in fact two valves, solenoid operate a small air valve, and air has to operate bigger valve, so it additionally require compressed air also reliably.

Rubber internals in pinch valves are classed for slurry service, which covers 'drain water'. And the ones in the link are threaded.

But the models I'm familiar with are air operated, not electrically operated.

https://www.usplastic.com/catalog/item.aspx?sku=31424&gclid=EAIaIQobChMIz4Xo9pmi3QIVRLnACh2pdABPEAQYAiABEgLQxfD_BwE

Maybe some Google-foo can find electric operated pinch valves (although I'm not sure what would look like).