[PSUBS-MAILIST] regulator for compensating

Fri Jan 15 17:10:08 EST 2021

 Hank / Alec / Cliff, this looks like it could be a good 3D printingproject that could be a custom solution forany psubber wanting to air compensate. Print a housing with a thread for the low pressure hose and valve opening mechanism. Either use a scuba diaphragm or a more robust off the shelf option & create an enclosure that encapsulates a spring (perhaps a plastic spring) rated for the over pressure needed. Design a port to fit a standard BCD over inflation valve and size its spring to suite. And finally add a hose fitting & maybe a means of attachment. The cad file could be exported to anyone that wants to get it printed! Alan 

    On Saturday, January 16, 2021, 10:20:11 AM GMT+13, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

  Alan, I have plugged one exhaust port and put an extension on the other.  May not be needed , but I cant hurt.Hank
    On Friday, January 15, 2021, 12:47:53 PM MST, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

  Hank, you could get a bit of overpressure in the system by putting a spring on the seaward side of the diaphragm (some how) & then maybe block off one of the exhaust ports and put in a BCD over expansion valve or similar. It's spring may be OK, but you could always change it out! Alan
    On Saturday, January 16, 2021, 08:34:34 AM GMT+13, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

  Hank, if you put the regulator in the bucket with the diaphragm face down, this helps cause free flow as the system is very sensitive & the water pressure on the disphram causes it to flow. That is when it's not in a divers mouth or in your case attached to a system it can pressurise. So mount it vertically or with the diaphragm to the top. If you narrowed the extentions to the exhaust ports you would get a bit of back pressure that would stop any free flow. All your system should be at the ambient pressure the diaphragm is exposed to. So if its 1ft down in a bucket you should have 1/2 psi in the system that is out of the water. Alan
    On Saturday, January 16, 2021, 01:16:11 AM GMT+13, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

  Emile, thank you, I did some testing yesterday with the regulator in a pail of water and connected to the arm actuators.  I removed the vent plug from the actuator to see how much air flows through the actuator.  Only a very small amount of air comes out the vent port before the regulator free flows.  I think that is due to the length of the small air lines to the actuators, plus there are wires in the hoses.  I then put extension tubes on the regulator vent ports and tried it.  There is a significant improvement in air flow coming out of the actuator vent port.  The question is, do I need the increased air flow? given the amount of things being compensated.Hank
    On Thursday, January 14, 2021, 11:21:55 PM MST, via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

Hank,

The lenght should be not a problem.You can create a small overpressure by placing the second stage as low as possible. Any water or condensation will be expelled during ascending as another advantage. Flow restriction sounds ok. 

Br,Emile

Van: Personal_Submersibles <personal_submersibles-bounces at psubs.org> Namens hank pronk via Personal_Submersibles
Verzonden: donderdag 14 januari 2021 21:16
Aan: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Onderwerp: [PSUBS-MAILIST] regulator for compensating

HI All, I have been playing around with and installing a first and second stage regulator on my ROV to compensate the arm etc.  Alan has raised a very valid concern.  The pressure differential between intake and exhaust is very slight and make me think the air may not make it to the arm motors.  Alan has suggested extending the exhaust ports to create more back pressure.  I was also thinking about restricting the volume allowed to exhaust, so if it free flows the restriction will help close the exhaust valve.  

Any thoughts on the matter?

Hank
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