[PSUBS-MAILIST] Parker Pressure Regulator

Wed Oct 16 01:15:13 EDT 2019

Thanks Alec, I can see your problem.
The Parker regulator I am using at the moment is the R374-O2C.
This looks pretty similar to Cliff's R364-02BSS/M1 but with an Aluminium
body. I just pulled it apart. You can see the small relieving hole in the 
brass centre of the diaphragm in attached photo.
I had a look at the relieving spring at the bottom of the regulator, thinking
I could replace it with a lighter Spring, but it has less power than a ball point pen.
You could cut a bit off it & see if it improves things but I think if you are air
compensating you have a lot of air going out through that small hole on
ascent & that will push the pressure up in the thruster. You could oil 
compensate with the same set up & only have a fraction of the air to expel,
but I guess you are considering the environment!
Alan

> On 16/10/2019, at 4:23 PM, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Hi Alan,
> 
> Great stuff there! I noticed that upon surfacing the compensation pressure was high and eventually dropped, so my assumption is this industrial reg just takes a while to gas off the excess. Certainly I see no sign of a large cross-section valve like all 2nd stages have. I too am shooting for about 5psi, but if possible no more. The reason is that my thrusters are jettisonable and are connected to the compensation lines through a little plastic tube that is designed to pull off if I drop a thruster. I have experimented and found that if I increase the compensation pressure above about 15psi, the hoses blow off. 
> 
> Best,
> Alec 
> 
>> On Tue, Oct 15, 2019 at 2:58 PM Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> Alec, thanks.
>> I have several scuba regulators on my ambient sub.
>> I used octopus regulators as they are slightly less sensitive so that they don't 
>> free flow. As per pictures below, I took off the mouth piece & attached some
>> some clear plastic tubing that I heated & forced on. On the exhausts I fitted
>> & glued PVC bends to keep air on the outer side of the exhaust valve & stop
>> water coming in the system. Not all regulators are the same so you need to
>> Source the most adaptable one. I believe it was Greg that liked the idea of the 
>> exhaust extension as he said he had been using regulators & getting a bit of water 
>> in his thrusters.
>> I had thought of machining a housing & fitting scuba second stage parts in it;
>> adding a spring to give 5 psi overpressure & using a BCD exhaust valve with
>> an appropriate sized spring in it.
>> I have an Ex military document on compensating motors, & 5 psi is the standard,
>> however there are large variations on that. Commercial compensator pressure
>> varies from around ( roughly) 3 to 9 psi over pressure depending on the oil level 
>> / Spring Extension. 
>> Is the off gassing volume going to be a problem? In the last 33ft to the surface 
>> the volume will double but even if it is still releasing air after you hit the surface
>> it shouldn't be an excessive pressure should it?
>> Karl Stanley was using a first stage regulator with spring removed ( gives ambient
>> pressure) for air compensation & said he just let the air bubble out the thruster seals.
>> Alan
>> <image1.PNG>
>> 
>> <image2.PNG>
>>> On 16/10/2019, at 4:31 AM, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> 
>>> I believe I have the same one as Cliff. I'm going to look into swapping it out for a SCUBA second stage, which I think will be both more sensitive and definitely able to handle a larger off-gasing volume. What I'm wondering about is how to connect something that's intended for a human mouth to Swagelok tubing instead. Any suggestions are welcome!
>>> 
>>> Thanks,
>>> Alec
>>> 
>>>> On Tue, Oct 15, 2019 at 1:14 AM Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>> Cliff & Alec,
>>>> I have just been playing around with my Parker miniature regulator.
>>>> As Alec noted there is quite a bit of pressure difference between the set
>>>> pressure & the relieving pressure. I have been turning the pressure up
>>>> to 20psi & then turning it down, & it takes a lot of turns to bring the pressure
>>>> down again. Ie. 1 full turn to go to 20psi but 2 full turns to drop pressure
>>>> back to zero.
>>>> I am using a cheaper Aluminium version for experimentation & bought the 
>>>> 0-125 psi range, which In hindsight was a mistake as I am not getting the 
>>>> sensitivity I need.
>>>> What range did you guys buy. I see you can get 0-25 psi.
>>>> I am running my thruster full of silicone oil & just a few inches of air in the feeder
>>>> tube from the regulator. 
>>>> Alan
>>>> 
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