<p dir="ltr">Just a quick look in the McMaster Carr catalog reveals 0-5000 psi pressure transducers. 1/4" NPT, all stainless with an 11,000 psi max pressure. I doubt they're rated for O2 though. If you're concerned about leaks, I wouldn't bother with the 1/8 tube, but instead put a second, much smaller, flow control orifice upstream from the bulkhead. A .01" diameter orifice gives you about .426 cfm at 3000psi. Then have a ball valve immediately coming off your bulkhead followed by the pressure transducer.</p>
<div class="gmail_extra"><br><div class="gmail_quote">On Oct 30, 2016 11:55 PM, "via Personal_Submersibles" <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.<wbr>org</a>> wrote:<br type="attribution"><blockquote class="m_7426136097646880115quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Send Personal_Submersibles mailing list submissions to<br>
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Today's Topics:<br>
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1. Re: Electronics contents gauge<br>
(Alan James via Personal_Submersibles)<br>
2. Re: Electronics contents gauge<br>
(Stephen Fordyce via Personal_Submersibles)<br>
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------------------------------<wbr>------------------------------<wbr>----------<br>
<br>
Message: 1<br>
Date: Mon, 31 Oct 2016 01:04:58 +0000 (UTC)<br>
From: Alan James via Personal_Submersibles<br>
<<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.o<wbr>rg</a>><br>
To: Personal Submersibles General Discussion<br>
<<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.o<wbr>rg</a>><br>
Subject: Re: [PSUBS-MAILIST] Electronics contents gauge<br>
Message-ID: <<a href="mailto:2109399614.868898.1477875898277@mail.yahoo.com" target="_blank">2109399614.868898.14778758982<wbr>77@mail.yahoo.com</a>><br>
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Thanks Emile & Steve.I may combine both suggestions.I am wanting to put my penetrations through a removeable platea la Deep Worker. It will be behind me in my 1 person submersible;so a pressure transmitter with wires coming from it rather than a gaugelooks like the right option.I like the idea of the 1/8th tube. I couldn't find a flow rate anywherefor a 1st stage hp port. May have to flow it in to a plastic bag & get anestimate, to see if a failure would be an issue anyway.?? Steve, are those pressure transmitters suitable for oxygen?Cheers Alan?<br>
<br>
From: Stephen Fordyce via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.o<wbr>rg</a>><br>
To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.o<wbr>rg</a>><br>
Sent: Monday, October 31, 2016 12:34 PM<br>
Subject: Re: [PSUBS-MAILIST] Electronics contents gauge<br>
<br>
Hi Alan,I?have pressure transmitters?(similar to many commonly used in industry)?that could probably be adapted for that - see attached photos.??You could replace the end section with a small penetrator/cable gland plate.? It needs a power supply of 6-30VDC and outputs 0.5-4.5V or 4-20mA (both linear).? They are NPT so you'd need an adaptor for the SCUBA?HP port - but a 1/4" Swagelok thread will fit.<br>
I imagine you're worried about?leaks?of HP inside, and maybe cost as well.??Something you may not have thought of is?running?1/8"?SS tube.? It's soft enough to?bend by hand (more like stiff solid-core electrical cable than 1/4" tube)?and can be run in a bundle with cables.? Also available in very small inside diameters so flow is greatly restricted.? I've had good success using it for remote gauge lines.<br>
I also have digital HP oxygen pressure gauges if you ever need one of those :).<br>
Shoot me an email at <a href="mailto:Stephen.fordyce@tfmengineering.com.au" target="_blank">Stephen.fordyce@tfmengineering<wbr>.com.au</a> if you're interested in one - list price is AU$198.<br>
Cheers,Steve(TFM Engineering Australia)<br>
On Mon, Oct 31, 2016 at 7:19 AM, emile via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.o<wbr>rg</a>> wrote:<br>
<br>
The scuba pressure sensors are wireless. Most scuba divers don?t want it as it is unreliable.?Best would be to screw a industrial pressure sensor (with ? ?thread or so) into the penetrator plate and attach a HP line on the outside.??Br, Emile?Van: Personal_Submersibles [mailto:<a href="mailto:personal_submersibles-" target="_blank">personal_submersibles-</a> <a href="mailto:bounces@psubs.org" target="_blank">bounces@psubs.org</a>] Namens Alan James via Personal_Submersibles<br>
Verzonden: zondag 30 oktober 2016 21:02<br>
Aan: Personal Submersibles General Discussion<br>
Onderwerp: [PSUBS-MAILIST] Electronics contents gauge?Is there a suitable electronic scuba tank contents gauge out there?I am after something that plugs in to the high pressure port of the1st stage regulator & has wires off it that I can run through a throughhull so?I can?display the tank contents pressure on a screen.Trying to avoid bringing high pressure in to the hull.An alternative may be to run a high pressure line to a throughhull & have an electronic pressure gauge threaded in to this from the inside of the hull. However with the second method, I wouldn't havea shut off valve if the pressure gauge failed some how.Alan<br>
?<br>
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Message: 2<br>
Date: Mon, 31 Oct 2016 14:53:49 +1100<br>
From: Stephen Fordyce via Personal_Submersibles<br>
<<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.o<wbr>rg</a>><br>
To: Personal Submersibles General Discussion<br>
<<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.o<wbr>rg</a>><br>
Subject: Re: [PSUBS-MAILIST] Electronics contents gauge<br>
Message-ID:<br>
<CAAzgXiNU_nw8bxJigff==<a href="mailto:V1ZGV%2Bech4DTnGrovRb-VcwbQmW%2BA@mail.gmail.com" target="_blank">V1ZGV+e<wbr>ch4DTnGrovRb-VcwbQmW+A@mail.gm<wbr>ail.com</a>><br>
Content-Type: text/plain; charset="utf-8"<br>
<br>
Hi Alan<br>
Yep, my pressure transmitter is suitable for oxygen (and is ranged<br>
0-400bar).<br>
<br>
A SCUBA reg HP port usually has an orifice built-in to restrict flow in the<br>
event of hose failure. But with even 100bar behind it, the tank will still<br>
empty in a matter of minutes - pretty significant. Having the<br>
prolonged restriction of a long skinny tube will help a bit, but a total<br>
failure would still put out a lot of gas.<br>
<br>
Cheers,<br>
Steve<br>
<br>
On Mon, Oct 31, 2016 at 12:04 PM, Alan James via Personal_Submersibles <<br>
<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.or<wbr>g</a>> wrote:<br>
<br>
> Thanks Emile & Steve.<br>
> I may combine both suggestions.<br>
> I am wanting to put my penetrations through a removeable plate<br>
> a la Deep Worker. It will be behind me in my 1 person submersible;<br>
> so a pressure transmitter with wires coming from it rather than a gauge<br>
> looks like the right option.<br>
> I like the idea of the 1/8th tube. I couldn't find a flow rate anywhere<br>
> for a 1st stage hp port. May have to flow it in to a plastic bag & get an<br>
> estimate, to see if a failure would be an issue anyway.<br>
> Steve, are those pressure transmitters suitable for oxygen?<br>
> Cheers Alan<br>
><br>
><br>
><br>
> ------------------------------<br>
> *From:* Stephen Fordyce via Personal_Submersibles <<br>
> <a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.or<wbr>g</a>><br>
> *To:* Personal Submersibles General Discussion <<br>
> <a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.or<wbr>g</a>><br>
> *Sent:* Monday, October 31, 2016 12:34 PM<br>
> *Subject:* Re: [PSUBS-MAILIST] Electronics contents gauge<br>
><br>
> Hi Alan,<br>
> I have pressure transmitters (similar to many commonly used in<br>
> industry) that could probably be adapted for that - see attached<br>
> photos. You could replace the end section with a small penetrator/cable<br>
> gland plate. It needs a power supply of 6-30VDC and outputs 0.5-4.5V or<br>
> 4-20mA (both linear). They are NPT so you'd need an adaptor for the<br>
> SCUBA HP port - but a 1/4" Swagelok thread will fit.<br>
><br>
> I imagine you're worried about leaks of HP inside, and maybe cost as<br>
> well. Something you may not have thought of is running 1/8" SS tube. It's<br>
> soft enough to bend by hand (more like stiff solid-core electrical cable<br>
> than 1/4" tube) and can be run in a bundle with cables. Also available in<br>
> very small inside diameters so flow is greatly restricted. I've had good<br>
> success using it for remote gauge lines.<br>
><br>
> I also have digital HP oxygen pressure gauges if you ever need one of<br>
> those :).<br>
><br>
> Shoot me an email at <a href="mailto:Stephen.fordyce@tfmengineering.com.au" target="_blank">Stephen.fordyce@tfmengineering<wbr>.com.au</a> if you're<br>
> interested in one - list price is AU$198.<br>
><br>
> Cheers,<br>
> Steve<br>
> (TFM Engineering Australia)<br>
><br>
> On Mon, Oct 31, 2016 at 7:19 AM, emile via Personal_Submersibles <<br>
> <a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.or<wbr>g</a>> wrote:<br>
><br>
> The scuba pressure sensors are wireless. Most scuba divers don?t want it<br>
> as it is unreliable.<br>
><br>
> Best would be to screw a industrial pressure sensor (with ? ?thread or so)<br>
> into the penetrator plate and attach a HP line on the outside.<br>
><br>
><br>
> Br, Emile<br>
><br>
> *Van:* Personal_Submersibles [mailto:<a href="mailto:personal_submersibles-" target="_blank">personal_submersibles-</a><br>
> <a href="mailto:bounces@psubs.org" target="_blank">bounces@psubs.org</a> <<a href="mailto:personal_submersibles-bounces@psubs.org" target="_blank">personal_submersibles-bounces<wbr>@psubs.org</a>>] *Namens *Alan<br>
> James via Personal_Submersibles<br>
> *Verzonden:* zondag 30 oktober 2016 21:02<br>
> *Aan:* Personal Submersibles General Discussion<br>
> *Onderwerp:* [PSUBS-MAILIST] Electronics contents gauge<br>
><br>
> Is there a suitable electronic scuba tank contents gauge out there?<br>
> I am after something that plugs in to the high pressure port of the<br>
> 1st stage regulator & has wires off it that I can run through a through<br>
> hull so I can display the tank contents pressure on a screen.<br>
> Trying to avoid bringing high pressure in to the hull.<br>
> An alternative may be to run a high pressure line to a through<br>
> hull & have an electronic pressure gauge threaded in to this from the<br>
> inside of the hull. However with the second method, I wouldn't have<br>
> a shut off valve if the pressure gauge failed some how.<br>
> Alan<br>
><br>
><br>
><br>
> ______________________________ _________________<br>
> Personal_Submersibles mailing list<br>
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