[PSUBS-MAILIST] Electronic contents gauge

Thu Nov 3 00:23:29 EDT 2016

Hi Alan,
These also exist and are pretty cheap, although not particularly oxygen
friendly:
http://valvesandregulators.aquaenvironment.com/item/check-valves-and-flow-limiting-devices/443-flow-fuse/443?&bc=100%7C1009

(I stock a couple of these for SCUBA tank filling, but they are not very
popular)

As you say, I don't think you will be able to use these with a SCUBA reg HP
port due to the restricted flow.

Cheers,
Steve

On Thu, Nov 3, 2016 at 7:48 AM, Alan via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Thanks Hugh,
> I just got a price of $160 NZ for a 1/4" 316 excess flow valve.
> A lot cheaper than I thought. However looking at the data on their standard
> XS4 series, the "trip" flow on 3000psi is 250 cubic ft per minute or 116
> litres
> per second. I had measured roughly 2 litres per second coming out of my
> 1st stage high pressure port.
> They do say they have smaller springs for tripping at a lower flow but it
> might be a big step to get to what I want ie. tripping with virtually no
> flow.
> For me I am leaning toward the option of potting the electronic gauge that
> Steve suggested & having wires through the hull to a plc. plus have
> contents
> gauges within view of my dome.
> Cheers Alan
>
>
> Sent from my iPad
>
> On 3/11/2016, at 8:34 am, Hugh Fulton via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Hi Hank / Alan,
>
> There are excess flow valves available for air/gas.  We make them but also
> Swagelok have them.  Ours are industrial for high gas flows.
>
> You need to make sure they are self resetting.  Hugh
>
>
>
> *From:* Personal_Submersibles [mailto:personal_submersibles-
> bounces at psubs.org <personal_submersibles-bounces at psubs.org>] *On Behalf
> Of *hank pronk via Personal_Submersibles
> *Sent:* Thursday, 3 November 2016 1:16 AM
> *To:* Personal Submersibles General Discussion
> *Subject:* Re: [PSUBS-MAILIST] Electronic contents gauge
>
>
>
> Alan,
>
> There is a hydraulic component on cranes etc the allows oil to flow at a
> set rate, but if the flow increases dramatically the component becomes a
> shut off valve.  This is to protect people and equipment in case a hose or
> seal blows out.  maybe there is aa air equivalent?
>
> Hank
>
>
>
> On Wednesday, November 2, 2016 3:43 AM, Alan James via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
>
> I just experimented with the flow from the high pressure port
>
> on my 1st stage regulator. That's the one your pressure gauge runs off.
>
> Even though the hole is literally a pin prick, I was getting at least
>
> 2 liters a second flow out of it.
>
> I am building a similar sized sub to Cliff's R300 & a leak like that,
>
> apart from increasing the pressure massively, would be hazardous
>
> if it was O2. In 4 minutes I could have 70% O2 based on an air
>
> volume in the sub of 250 liters.
>
> I think I'll go for a pressure gauge outside my view port or try potting
>
> a digital pressure gauge & just send the wires through a penetrator.
>
> Alan
>
>
> ------------------------------
>
> *From:* Alan via Personal_Submersibles <personal_submersibles at psubs.org>
> *To:* Personal Submersibles General Discussion <
> personal_submersibles at psubs.org>
> *Sent:* Wednesday, November 2, 2016 12:41 AM
> *Subject:* Re: [PSUBS-MAILIST] Electronic contents gauge
>
>
>
> Thanks for the advice Steve.
>
> I haven't looked in to the electronic oxygen add system too deeply.
>
> Bound to have some questions later on.
>
> Cheers Alan
>
>
> Sent from my iPad
>
>
> On 1/11/2016, at 9:39 pm, Stephen Fordyce via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Thanks Alan - I should probably point out that my Watchdogs are rather
> literally named - ie. they can sense something is wrong and do
> something simple about it, but are limited in how complex the reaction can
> be.  It can only handle one O2 input, and the control is limited
> by controller settings - it's an off-the-shelf item and not fully
> programmable like a PLC.  Good for an independent backup or alarm.  As a
> primary system it could be made to work but would require a thoughtful
> setup.
>
>
>
> Eventually I do plan to make a rebreather controller (for the rebreather
> I'm designing) which would be perfect (many O2 cell inputs and a solenoid
> or two output), but that's a while away!
>
>
>
> A key thing to consider in automatic oxygen adding is placement of
> sensors, natural mixing of the air and sufficient time delay in the control
> system to get meaningful feedback before the next oxygen
> injection (Ie. rebreather controllers squirt a little bit of oxygen in,
> wait a few seconds for it to mix, and then measure, and squirt in more
> accordingly).
>
>
>
> Cheers,
>
> Steve
>
>
>
> PS: I also have some M12 plated brass Blue Globe cable glands if you find
> yourself short a couple - very hard to get down here.
>
>
>
>
>
>
>
> On Tue, Nov 1, 2016 at 2:19 PM, Alan James via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>
> Steve,
>
> sending this again as I didn't receive it...
>
> Steve,
>
> I am wanting to build an O2 system like James Cameron had.
>
> An O2 valve that flows continuously with a top up from a solenoid
>
> valve which  triggered by a plc that is receiving signals from 3 x O2
> sensors.
>
> Mainly because I want to keep everything as small as possible.
>
>    With your O2 unit it looks like you could have it doing similar;
>
> turn on a solenoid to top up the O2 beyond what is flowing in from
>
> a pre-set valve. A bellows add system that replaces the bellows with
>
> your "Oxygen Watchdog"
>
> Know what you mean about UK freight charges, have cancelled items
>
> because of ridiculous freight charges. Thanks for the offer of buying
>
> through your firm.
>
> Cheers Alan
>
>
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