[PSUBS-MAILIST] flow meters

Tue Mar 13 17:53:31 EDT 2018

Rick,
just to make it more complicated; you need to monitor the contents of
your O2 tank, so this may mean bringing the high pressure on to a through
hull to read on an internal gauge. In which case you may as well have a
regulator off this to your flow meter. Whether you do this off the high pressure
port of your first stage or not I am not sure. You would have enough flow from
it for your life support system. It may pay to ask how all the Psubbers
are doing it & debate the pros & cons.
I have had some electronic pressure gauges built with a male fitting compatible
with a first stage high pressure port, & are pressure proofing them. So
will only have wires not hp on to the sub.
Cheers Alan

Sent from my iPad

> On 14/03/2018, at 10:27 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Rick,
> I bought it when I was first going to build a 1atm but didn't install
> it as I built an ambient first.
>    I would guess that half the Psubbers have a similar click style regulator
> & half use a flow meter. I am going with a variation on the "belows add"
> system where the flow is set below your minimum requirement ( so as to never
> be able to over-pressurise) & the balance of O2 is added by a bellows or
> electronically off O2 or pressure readings.
> I am pretty sure on the Triton 3000 the pilot was just manually adjusting the flow
> meter off O2 readings like they did in the old days. If you are adjusting manually
> then the flow meter would be better because the click style regulator  "clicks"
> around to varying range increments whereas you could get a finer adjustment
> with the flow meter.
> Mine is a CGA fitting brass sleeved 50psi O2 regulator, 0-4 LPM. Model AREG5404
> with input pressure max of 2600 psi.  And yes I am running it off an O2 cleaned first stage regulator to keep high pressure O2 away from the hull & the various
> hardware down line from the regulator. 
> You can adjust the pressure above ambient out of some first stage regulators
> by replacing the spring. I tried a system of air compensation that Karl Stanley
> uses; he just takes the spring out of a first stage regulator & that gives him
> ambient pressure.
> Alan
>  
> 
> Sent from my iPad
> 
>> On 14/03/2018, at 8:49 AM, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Hi Alan,
>> 
>> I thought about the fact that the pressure to the inside of the sub would be increasing with depth after I sent the post. Are you also breaking down the HP to LP at the bottle outside the sub? Did you buy the regulator/flow meter you showed me? 
>> 
>> Rick
>> 
>> 
>> 
>>> On Tue, Mar 13, 2018 at 9:13 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> Rick,
>>> as you say "above ambient" so at 350' depth you will have 130psi
>>> coming out of the regulator plus another 175psi for the ambient depth.
>>> EMT have this...https://www.emtmedicalco.com/GENTEC-OXYGEN-FLOWMETER-WITH-REGULATOR-0-15-LPM-CGA-870-OR-540-191M.htm
>>> I bought a pressure regulator for inside the hull to deal with that,
>>> however the click style paediatric regulators they have take a high inlet pressure
>>> although I can't see any literature on this at EMT.....
>>> https://www.emtmedicalco.com/PEDIATRIC-REGULATORS-0-4-LPM-CGA-870-8704.htm
>>> Alan
>>> 
>>> 
>>> Sent from my iPad
>>> 
>>>> On 14/03/2018, at 6:53 AM, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>> 
>>>> Was looking into buying an 02 flow meter yesterday online and was told that the incoming pressure to the meter had a max incoming working pressure of 50 psi. My bottles will be on the outside and I have two 02 cleaned first stage regulators that will take them from HP to LP then into the sub.
>>>>  I guess the average LP setting is  around 150 psi + -above ambient? so I should be able to have a dive shop re set them down to 50 psi? What have others done that have the same scenario and wonder if there are flow meters that can take the 150 psi in?
>>>> 
>>>> Rick
>>>> _______________________________________________
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>>> 
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>> 
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