[PSUBS-MAILIST] Solenoid valve

Thu Jun 23 18:36:46 EDT 2016

Sean, Jon.that is similar to Vance's design, using an air cylinder to actuate the ballast valve,however you have added a solenoid valve in the system so that it can be controlled electronically.That requires the addition of an extra piece of hardware. You could start with something like this air core solenoid (below) or just wrap wire from an oldtransformer round a plastic tube. Then dunk it in resin, however the wires are insulated anyway so it would be a matter of concentrating on potting the terminations. Then get an undersized iron rod so it has a sloppy fit, & dunk that in resin.The rod is only moving inside the coil a couple of times every dive, so friction & wearwon't be an issue. You would only need to design it bigger to get the strength you needed,& so that it ran cool. The power consumption would be a non issue as it is onlyrunning for about 30 seconds a couple of times per dive.I made a solenoid valve from an old solenoid & a toilet ball valve. It worked but becausethe solenoid was so small it did heat up quickly.Cheers Alan  

      From: Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Friday, June 24, 2016 12:52 AM
 Subject: Re: [PSUBS-MAILIST] Solenoid valve

I have solved similar problems by using small solenoid valves to control the application of low pressure air (<100 psi) to the exposed valve, which is air actuated.  This way, all of the electronics are protected from the outside environment, easily repairable / replaceable, and can be observed for correct function. The air signal from the first valve is then what would pass through the hull, so it would have a safety shutoff at the through hull, and then the second (larger) valve is entirely mechanical in nature and made of materials compatible with the environment. I have used several different versions of this, but the solenoid valves I use most often now are Asco Red Hat Next Generation solenoid valves with 24 VDC coils, because they appear to have the least constant power draw when actuated of all the options I've tried.  1/4" is all you nee! d forair, unless you have a particularly huge second valve that requires a fast actuation time. I do something similar with proportional valves too, using an I/P converter (proportional regulator) to convert 4-20 mA control signals to 0-15 psi pilot air pressure which is sent to a large proportional valve which is exposed to a H2S environment.Sean

On June 23, 2016 5:49:13 AM MDT, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
Hank,I thought of putting bellows around the plunger & oil filling the solenoid,but I would need another set of bellows or something to compensatefor the displaced oil when the plunger retracted.I Googled to try & find a suitable off the shelf valve but couldn't find anything.This design should be fine. It will be corrosion proof  & work at any depth. I am not sure I like the retaining system of the solenoid & might look around for something off the shelf I can adapt.Alan
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On 23/06/2016, at 11:26 pm, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Alan,Perhaps an oil filled enclosure could be built around the valve.  I have never potted anything on one of these valves, they go strait from the box to the sub (ROV).Hank 

    On Thursday, June 23, 2016 5:18 AM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

  James,I have attached a solenoid valve design based on Vance's  pneumaticallyoperated top hat ballast valve. It was done quickly & is open comment & being evolved.   A solenoid is just a coil of wire with an iron core plunger. As long as the solenoid& plunger are coated with epoxy or similar this simple design should work.The solenoid is clamped in place by the two circular plates & the retaining bolts.(didn't put thread on the bolts) The neoprene gasket seals on it's seat by the springspressure & air pressure in the ballast tanks. when power is on the solenoid itdraws the plunger in to it, which pulls the gasket seal open.A solenoid is easy to make but it may take some experimentation to get the right gauge of wire & number of windings, so that it opens the valve but doesn'theat up excessively.The other neoprene gaskets shown are for sealing to thehull.Some sought of gauze needs placing round it to stop foreign matter gettingin the valve seat. Alan

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