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

[Alec Smyth via Personal_Submersibles]

Hi Steve,

I use a 1st stage outside the hull. As you say the flow regulator can
handle the tank pressure, so it is not strictly necessary, but I do so as
an extra safety precaution to avoid bringing high pressure O2 inside. If
doing it again I would the reg directly on the tank, so that way all of the
tubing would see only low pressure.

I'm using a 1st stage that is incredibly inexpensive ($60), but I'm
delighted with the quality and what is a big plus for me, it's a
particularly simple design. I've collected three of them by now, and not
any problem at all.

https://www.piranhadivemfg.com/item/Balance-Piston-Din-First-Stage--For-Pony--Stage-Bottles--Nitrox-Ready-11738

I do my own oxygen cleaning on tubing and penetrators, but prefer to buy
O2-clean regs and valves. You may notice this reg is advertised for Nitrox,
not pure oxygen. I spoke to the owner of the business selling it, and he
told me the cleaning and materials are identical for partial or full O2,
but that they advertise it only for partial O2 use as a legal CYA.


Best,
Alec

On Mon, Dec 25, 2017 at 12:50 PM, 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:
>
>    1. They sell regulators that are already suitable for 100% O2 use. How
>    difficult to clean one that is not O2 ready?
>    2. 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.
>       1. 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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