[PSUBS-MAILIST] First Stage Regulator for O2 service Questions

[Alan via Personal_Submersibles]

Steve,
I had some regulators O2 cleaned. The dive shop which specialised in technical
diving said they could only O2 clean certain regulators, & recommended a 
couple of models. I believe someone on Psubs disagreed with this & thought
all regulators could be O2 cleaned, but that was my experience. I would suggest
you ask the dive shop you intend to deal with about this. 
I wouldn't worry about an expensive regulator as you are not breathing from
it directly so the subtleties of performance  would be of no use. 
You need to monitor the contents of your tank, & a first stage regulator has
high pressure ports for your pressure gauge. I am not sure how Hank does this
with the O2 high pressure direct on to the sub; probably an internal gauge.
Another factor in the equation is where you are going to get the O2 filled.
If you are getting it filled at a dive shop, the tank will require a scuba type 
fitting, & they may require some sort of certification. Even though I was a diver
I'm not qualified for mixed gas diving & they required me to do a " Emergency O2
provider" course. If you are intending to fill at a medical O2 supplier / industrial
gas supplier, then you will need a different tank fitting. 
I am only feeding low pressure O2 to my hull, mainly because it is a one person sub 
& the pressure could build up a lot quicker with a leak.
Cheers Alan

Sent from my iPad

> On 26/12/2017, at 6:50 AM, Steve McQueen via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> All, I am purchasing the system components for my K-250’s O2 system.  I am not a SCUBA diver so I lack some experience with regulators. I am considering sealed/balanced options for the first stage regulator (it will create an intermediate pressure downstream of the O2 tank (located external of the hull). These get pricey and I don’t really want to overspend for options I do not need (sealed vs. not, balanced vs. unbalanced, O2 ready vs. needing cleaned).
>  
> A couple of questions:
> They sell regulators that are already suitable for 100% O2 use. How difficult to clean one that is not O2 ready?
> The pediatric flow regulator (located in the hull) can directly handle the O2 tank pressure so I am wondering why we use the first stage regulators at all.
> I assume to remove as many HP leak sources from within the hull especially since it is 100% O2 (safety).
>  
> Thoughts/recommendations?
>  
> Steve
>  
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