inside a cheap eBay solenoid water valve. 

Absolute perfect description of a pilot-operated valve (for either pneumatic or hydraulic). I work with solenoid valves, pressure regulators and pneumatic relays on a daily basis, and you nailed it with a very easy to understand theory of operation regarding pressure differential on either side of a diaphragm.

Saw the thumbnail, thought someone invented the smallest flushing toilet. Dang.

Now i finally really understand how this works. Thank you very much !!!

yeah you could use it with an Arduino to make an automated watering system

Spot on with spring! Its purpose is to clean the compensating port and it's patented by the company I happen to work for :-) Btw. very nice explanation of the servo mechanism!

That solenoid valve looks almost identical to one I replaced recently in a truly cheap and nasty Montpelier washing machine. The coil had gone O/C, I didn't investigate the reason.

I use a lawn sprinkler valve to turn off all my water in the house until I need it. My water system leaks everywhere and I can't afford to replace it. So, rather than let the house be destroyed and my water bill go to extremes, I put the valve on my water intake. It has worked for several years, now.

Oddly enough my old electronics teacher gave me the first explanation of these ingenious valves - I think the context was an automatic bath filler with temperature control. It never happened - we couldn't find low voltage ones at a reasonable cost...and tbh the idea was a bit rubbish... I'd fancy this for greenhouse applications or perhaps a PIR operated anti-cat watercannon.

1:10 - KHAAAAANNNNN! Sorry, I had a Star Trek moment. ;-) It seems cheap enough that one probably would not want to disassemble it... And inexpensive enough to not bother rebuilding them if the diaphragm fails, just replace the whole unit for a few bucks. It is, however, a nice little unit to have for a clothes washer water inlet replacement if the original fails... I could also see it applied for light-duty irrigation, hydroponics, water features, even for DIY heat pumps. Quite a nice find, Clive!

Hey big clive! Can you show us your workbench area that would be cool, i really enjoy your videos they are awesome! Wow im first to comment!

I Wouldnt want to put much pressure through that.. It would blow apart.. I second the request for a work bench tour. Would be cool to see. Take Care..

I remember Tim Hunkin explaining this incredibly clever device on The Secret Life of Machines circa 1986. I had in fact forgotten about the actual design of the diaphragm so this has been a nice revision session for me. Thanks a lot

You explained it really well, I wonder what the maximum pressure that it can cope with is?

Fill it with water cap both ends then throw it in the freezer : ) .

Entertaining as always. Question, i was looking online for a atx power adapter that would allow me to go from say the 12v rail and be able to adjust the voltage and current. I know about the little dangerous prototypes board as well as the little boost buck converters but i cant seem to find and dont know why just a box that you plug the 24 pin into and has those adjustments built in. Are you aware of such a thing? If not you should make em:)

Modern toilet cisterns have fill valves which work with the same method - it means the float can be much smaller as the force required is less than a traditional ballcock and valve assembly which equates to smaller, neater cisterns.

Your discussion and drawing were very elucidating, many thanks Clive. I construct irrigation systems but haven't yet had need to service a valve interior, and so wasn't aware of the clever force multiplier effect of the diaphragm. I've confirmed that the landscape grade valves I use operate on this same principle (although the solenoids actuate on 24VAC, presumably because of the long cable runs required). I'll have to order a couple of these cheapies to play around with for toy aquaponic systems and the like. Come to think of it, I wonder if the valve may not positively close under low pressure intakes, such as gravity feeds...

trick or treat 😝 how can viewers send you mail.. I have a brand new clamp meter for you to review and take apart

not in a bad way, a good way, but your videos are so interesting and soothing that a lot of the time i fall asleep watching them lol

tried using these valves for airgun, found out that slightest hit to it could lead to actuation of the valve, thus rendering the gun unsafe whenever the reservoir is inflated up

I use one very similar connected to a raspberry pi that also has one of those soil moisture probes connected to it. didnt trust it on a mains fed water supply so it controls a gravity fed water tank that collects rainwater. Built it to keep my cucumbers watered in the summer but by the time I finished it the summer was over.. always next year...

Agree with others here Clive that these are are common in washing machines where feed pipes fix to the rear of the machine itself.

Hey Clive, great video as usual. That black and silver screwdriver (that you use), is it a pound shop one, I ask only because I bought one from my local pound shop. When I saw it I thought 'Big Clive has one like that'. I have also paused one of your vid's that have the said screwdriver in it, to get a good look. I think I have the same one as you.

the springy thing on the valve and stem is a anti hydrolock feature.

I can't decide whether to spend the rest of my life calling these "water transistors" or "H2OFETs".

I used one of these valves to make a potato gun, but the amount fluid that can flow is very restricted so reduced the power of the potato, does anyone of a more suitable electronic valve that can let a larger volume of air flow

I'd not be surprised if that Brass was DZR brass - allowing for variation in monitor performance, the shade seems "just right". The inline filter is a nice extra too - not particularly fine, but obviously someone's thought about this, and the end product is all the better for it. Chinese quality is RAPIDLY improving, and I'd expect the same transition in perception as we saw with Japanese cars - originally poorly-regarded, now the Industry standard.

It has been designed for low pressure which is why it has the extra spring. The important parts are the quality of the rubber and type of steel used in the plunger so it just not rust and jam. Same quality as used in you washing machine at a fraction of the price. but 230/110 volts Ex Factory FOB prices are around $1.50 -$3 on a lot of brands. If your lucky have a look on line you may see the same brand with a different fittings, and just change the inside round. Failure to fill fast is normally a small hole in the rubber part keeping the valve closed. Most were made in Italy a few years ago.

The solenoid changes the water pressure from one side of the diaphragm to the other pushing it open or closed depending on the position of the tiny pin . This works exactly like a washer inlet valve. I have taken many apart and cleaned them when they either dond open or close compleatly ; ( usually what goes wrong with them in washers. Why replace when if you clean out the grit they work like new again , provided lightning or a power surge has not killed the coil ; which could only happen if it was activated at the time of the over voltage . Very unlikely.

Cool, thanks Clive. Been looking at these (among other solutions) for an auto watering setup for a friends allotment. Nice to see inside of one before deciding.

Very interesting and a nice explanation of how it works. Thanks

i would say its probably aluminium bronze, its both cheaper to make than brass and has good corrosion properties.

I wonder if they might be useable for my central heating system. Every radiator has its own set of tubes. If I could give every room it's own temperature sensor, and run the whole setup on a simple plc, there might be quite some savings possible. If only this Chinese stuff would do a few 100.000 reliable cycles ... :)

They ought to get William Shatner to advertise for them, seeing as it's a KHAAAAAANNNN!!!!!!!!

The classic "Secret Life of Machines" episode on Washing Machines explains in detail how these work, including why there are holes in the diaphragm, etc. The solenoid part starts at 9:45 -- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-baFaEvBywGc.htmlm45s The whole series is amazing!

But...Does it work now?

Almost every single video on your channel has "Hochland Toast-It" advert in front of it, the 15s skippable kind of ad. I get hungry every single time, seeing the clock being 1:30am doesn't really help the situation :D

Would any solenoid valve be ok for drinkable water or do they make special type for that? I'd use it to fill a coffee maker with water.

Nice! Your explanation is so much clearer than the textbooks ..... (or maybe it's just your mesmerising, mellifluous voice .....) What is the thread on the pipe fittings? Could you use 15 mm. olives and compression nuts? Or would it have to be hose connectors?

Excellent video. Do you know if those kind of valves can be used in a low pressure water system? I need to control the out of an IBC water tank and this might handy, but I'm afraid the water pressure would not be enough to make it fully operational. Thank you.

If I was going to use that then I'd probably drill out the holes and add some threaded brass inserts to the plastic body.

Could Clive be the actor in "The Gods Must be Crazy" film? In the film, he had a Land Rover with no brakes, no windshield and a dead battery. Over-tight pistons would not allow him to turn off the engine. Sounds like him and acts like him. If you have not seen the film, you must! Utterly hilarious.

Hose fittings look like anodized aluminum--if so, no damn good. The aluminum will corrode to aluminum oxide--the stuff they make sandpaper from. If it felt heavy in the hand, that's brass, but I've had all kinds of things spoiled by aluminum fittings.

Naah, this is not even general use. More like household use. I don't think it can work at more than 3 bars. It really is "worth" the money, it's a very poor quality valve. You should also know that there are more types of valves. I think this one is a floating diaphragm. You can also have hung diaphragm, hung piston and floating piston. Also, that little bit from the spring that goes into the hole in the membrane could also protect against water hammer effect.

bigclive would you entertain a video of something like a diy digital ocilloscope kit? Theres loads on Bang good.com and they are cheap? Just thought you"d be great at reviewing stuff like that, maybe you could get free-bees by contacting company in return of a review??

Or used to make a DIY ventilator out of a common CPAP machine during the COVID19 pandemic.

I wouldn't want to put too much pressure on that thing, it would rip the screws out of the brass ends.

I like your videos it's like watching an episode of Absolutely!

Would this be fast enough for a pneumatic potato gun quick release?

Add a PIR and timer for an automated cat scarer and would be burglar wetter. (for avid bird feeders and burglar deterrers). 'Sorry postie!'

Just like the officer says "Move Along, Nothing To See Here". Not that would stop Clive. Lets get to the guts.

"The diaphragm has a pinhole through its center which allows a very small amount of water to flow through it. This water fills the cavity on the other side of the diaphragm so that pressure is equal on both sides of the diaphragm, however the compressed spring supplies a net downward force. The spring is weak and is only able to close the inlet because water pressure is equalized on both sides of the diaphragm." en.wikipedia.org/wiki/Solenoid_valve#Internally_piloted

Cheap nasty solenoid control valve, The springs will most likely rust within 12months, the main diaphragm will erode in a similar period and potentially cause a minor disaster. Glad to see the tear down changed my mind on getting one will spend the money a buy an industrial quality unit.

Great video! I have learnt something! Thank you Clive! 🤗

A quite clever design. Thanks for sharing it with us.

"Automated Plant Watering Devices" :P Sounds... interesting. xD

Try to see the various potato gun builders' descriptions and teardowns of the Rainbird solenoid valves. This seems to be basically the same.

I am a heatpump technician work i whit so many different technical thing's looks a lot of what you do in the Dutch I like your video's

Thank you for the explanaion. Now I know why they don't work unless there's lots of pressure. I need to open and close a tap that has no pressure!

Just add a shower head, a bell button labeled "cold shower", a battery and connect it to the garden hose. Just the right thing for these little monsters that have fun to push all bell buttons and run away. ;)

Still watching... but did you mistake inlet for outlet... seems like the inlet would be before the shutoff mechanism and the clean out would be after the shut off mech and before the outlet... back to the video lol

Interesting film, thank you, learnt something :)

Can you do a review on the Thrunite flash lights? They seem very simple but cost a fortune.

When I lived in England, I had a few just like this. In the states, I can't find one at the same cost with US threads.

I like fish and chips!

You could make an auto dog water bowl filler with it having a weight sensor on a mat the bowl is secured to turn it off when the bowl is full or when the dog is present.

That filter would be critical to continued operation. If a bit of something gets embedded into the diaphragm, the valve might never shut off!

Can you post a link for the supplier? Having a problem finding it.

Very open-able and turn-off and on-able. :)

Would be nice if you`d make some videos about chinese cheap pneumatic parts

I don't see those cheap-o self-tapping screws holding reliably against domestic water pressure.

Am I the only one disappointed that he didn't test it on an actual water supply? :P

connect one of them onto your a/c condencer when she kicks on spray water on condencer it will blow ice cold i allways wanted to do that

are the springs stainless steel? a standard steel spring will rust very quickly.

I can't find that particular solenoid valve on ebay.

That diaphragm looks very similar to the one I have to replace on the inlet valve to my toilet cistern (every few years). I never understood how they worked... I just about get it now, but I think I will have to watch this video a few more times.

You missed out on the "easy to remove and clean FIlter".

P.P.S. Can you post the link to buy this valve.

Just like a Sloan type toilet valve.

water might push open and coil shuts off?

Clive you gotta use it on a whiskey bottle hanging upside down, then you can make a remote control and a relay powering/depowering the valve and bob is your uncle ;-)

Do gas valve diaphragms operate in the same fashion??

possible PC water cooling application?

What is the max water temperature this would work with?

I tried using a solenoid valve like this to control a bucket-fed drip irrigation system, but it was a total fail because these valves require a certain amount of water pressure to work, and the bucket's few feet (less than a meter) of height was insufficient. Looking at your dissection, I guess that's because low water pressure is unable to press open the diaphragm. A motorized ball valve (off eBay) did work for me. They're more expensive, but would be cool if you could tear one apart some day.

It looks very similar in function to a SIAMP diaphragm valve that my loo uses :-) Unfortunately they have a relatively short life span which is exacerbated by higher water pressures :-/

How could we get this to work for a school project

Do you know a kind of "fail safe" valve that restricts water flow if a pipe/hose would burst, but allows normal flow for a short period of time if there wasn't any flow for some time?

Hi Clive, this is fantastic. We have 2 x 12volt solenoid valves on our boat toilets to control the flushing water. These have been a pain of my life for the last 10 years as they are always leaking when the small transfer hole blocks. Thus the water ends up continuing to flow and flooding over the bowl. That little tag on the spring to keep the hole clear is such a simple idea. My valves are made by Jabsco and cost over £100 each. I will be order 2 of these plus 2 more for spares asap. Thanks for the tip. I will post a video of these being fitted and a link to this video on our channel. PS Thanks for all your videos they provide endless hours of entertainment and information for us fellow geeks! 🙂

Pressure difference will close the valve

Same princip used in refrigeration.

Stick some warm white LEDs in it.

Aargh. I'd worry about the screws popping out the body and flooding the house. Absolutely unusable for anything permanent. Thanks for showing that!

more industrial ... PLEASE

I use one of these solenoid valves connected to a ZJ-LCD-M flow meter on my brewery (real ale). I use it between the HLT and mashtun so I can measure the volumes of water. Works well most of the time but not and again it stops, I think the water gets too hot as the valves are rated at 80 degrees C maximum.

Looks like it is some sort of equilibrium valve.

Hey Clive, did you fit that central heating water filter from your video a while back? Curious to know how much crap has collected inside if you'd consider revisiting it?

Clive. Look back on your notepad sketch, you missed an important point that you drew perfectly. The force on the top of the diaphragm is higher than it is below because of the unequal area. When the pilot spool blocks the hole in the centre and the diaphragm seals the exhaust port, the area of the underside of the diaphragm is reduced by the area of the exhaust port. As the inlet water pressure is free to equalise through the bleed hole it is the different area of diaphragm exposed to this equal pressure that seals the diaphragm down hard on to the port. When the pilot spool lifts off the diaphragm the inbalance is lost as the hole in the diaphragm allows the cavity above the diaphragm to fall down to the exhaust port pressure and so the diaphragm is lifted by the higher inlet port pressure. The force of the helper springs become insignificant as water starts to lift the diaphragm seal. The small size of the bleed hole means that so little water passes up through the diaphragm compared to the flow (and pressure) down through the pilot valve that again the water pressure is doing the work. The reason for the check valve just inside the outlet flange is to make sure that the exhaust pressure is lower than inlet if possible otherwise the diaphragm is forced closed and not open as the pilot valve opens. Does any of that make sense? Garry

Great explanation. Just to add - no wonder there is a filter and no wonder it is easily serviceable, because (I guess) in case of water not being perfectly clear it could easily clog those tiny holes.

clive i'm not complaining, but i did notice a minor amount of distortion in the audio on this video, i just thought you would like to know that because you were changing up the mic setup in past videos, possible the mic was clipping, but as always a rather interesting video, i really do enjoy you're channel a lot :)