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Re: [PSUBS-MAILIST]

Alan,
 
Just was thinking that if the MK 2 that you bought is a standard scuba first stage, I am not sure but I don't think you can get more than 150 PSI out of it and so if you at the Max working depth of the K-350, you wouldn't have enough PSI to get the 02 inside the sub. My source in Seattle found a company (Apex) that makes first stages that will push well beyond the 150 PSI and are 02 cleaned and can be submerged but start around $500. It also has a "DIN" attachment on it so the 02 bottles would also need to have that which also drives up the price. As much as I would like to keep all the high pressure gas on the outside of the sub I may have to give in and have to go with the silica bronze threw hull and conventional regulator inside. Your thoughts?
 
Rick

From: Alan James
Sent: Wednesday, July 20, 2011 1:07 PM
Subject: Re: [PSUBS-MAILIST]

Hi Rick,
I was offered 2 options of first stage regulators that could be O2 cleaned.
I took the cheaper option. Once it's O2 cleaned it's pretty well dedicated to sub use unless you
use it for high percentage nitrox diving. If you put air through it again you're supposed to O2 clean it again.
So as a dedicated submarine 1st stage regulator, it wouldn't be as critical as it would be for diving.
i.e. if it failed you would still have a cabin full of air to last you a while.
I don't know why Global dive Auckland suggested it; but they seem to be a leader in technical diving, do O2 fills
& had experience in O2 cleaning regulators. Maybe it's what they were familiar with & capable of operating on.
I googled "O2 cleaning first stage regulators" & there seemed to be a few options, however they are O2 cleaning for
nitrox wich has a maximum 40% O2  content whereas we have 100%.
If your guy is suggesting something, & he can O2 clean it, go with that. At least you will have avoided the trap of buying
a first stage regulator & finding it can't be O2 cleaned.
Good luck,
Alan 
----- Original Message -----
From: Land N Sea
Sent: Thursday, July 21, 2011 10:17 AM
Subject: Re: [PSUBS-MAILIST]

Hi Alan,
 
I called a friend of mine who owns several dive shops in Seattle and was going to buy the Scubapro MK 2 first stage as you had mentioned. He said that he wasn't a scubapro rep but was familiar with that system and said that it was an old design and not that good of a first stage due to being piston operated. He suggested I go with a first stage that has a diaphragm instead of a piston and that it could be 02 cleaned. He also asked me to check with anyone on this site that might know why that particular first stage was suggested?
I assume the diaphragm is rubber and maybe the rubber and 02 are not a good match?
 
Rick

From: Alan James
Sent: Wednesday, July 20, 2011 11:28 AM
Subject: Re: [PSUBS-MAILIST]

I had an electronic version of the bellows add system made up for me.
A vaccum sensor triggers a solenoid valve that lets in O2 when the pressure drops.
It also displays pressure readings.
I haven't put air lines in to my hull so haven't tried it out yet.
I think Cliff has a similar system, but his operates in response to O2 level readings.
Regards Alan
----- Original Message -----
Sent: Thursday, July 21, 2011 8:25 AM
Subject: RE: [PSUBS-MAILIST]

I was never able to source that little metal bellow. If anyone knows where to get them, please let me know!
 
Alec


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From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Daniel D. Lance
Sent: Wednesday, July 20, 2011 4:17 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST]

This system works brilliantly. The heart of the demand valve is a small bellows. Maybe Phil would give us some specifications of it.

On 7/19/2011 10:38 PM, Land N Sea wrote:
Thanks Al
 
I took a quick look at it and the picture quality isn't good but will read the text and hopefully get the just of it.
 
Rick

From: Al Secor
Sent: Tuesday, July 19, 2011 3:24 PM
Subject: RE: [PSUBS-MAILIST]

Rick,

 

Don’t mean to step on Dan’s toes but I think this is what you are looking for:

 

http://www.psubs.org/design/lifesupport/lifesupport.pdf

 

Al Secor

 

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Land N Sea
Sent: Tuesday, July 19, 2011 9:14 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST]

 

Dan,

 

Do you have a drawing or data on Phil's tilt/demand system?

 

Rick

 

Sent: Thursday, June 30, 2011 2:22 PM

Subject: Re: [PSUBS-MAILIST]

 

Rick,
I built my K-350 according to the plans and made the Phos. bronze fittings. If I had it to do over again I would skip that part and bring the O2 into the cabin at low pressure instead of high. Stainless steel is not favored for HP oxygen service. Phil Nuytten has the best system going with the tilt  / demand valve.
Dan Lance

On 6/29/2011 10:49 PM, Land N Sea wrote:

I am building a K-350 and am trying to get as many thru hull fittings welded in as I can before welding the end caps on. For anyone who has the plans for a K-350, did you actually follow drawing 041-2? it is the Phos. bronze removable piece for the 02 to pass threw and looks quite expensive to machine if not doing it yourself.

I would like to hear from anyone regardless of boat type that uses an 02 life support system what they welded in for a threw hull fitting. I can't see why I just can't weld in a schedule 80 ss 316-L pipe coupling then screw into that a HP valve then HP to LP 02 regulator then a proper flow meter for 02?? I would 02 clean the nipples and coupler of course. Also any feed back for the ID of pipe I should use would be appreciated.

 

Rick P.