[PSUBS-MAILIST] HP air whip

[Sean T. Stevenson via Personal_Submersibles]

Jon - LP tubing and fittings are not necessarily cheaper than HP, as the line size comes in to play in that calculation. Do a worst-case scenario downstream demand calculation on the LP gas, and work back to what size of HP tubing would be required to deliver that at your service pressure. You might be able to get away with less substantial parts. Also, consider that any pressure reducing regulator is going to get cold in the presence of flow due to adiabatic cooling - what is the downside risk of a regulator freeze if it is outside the hull? As much as HP lines within the personnel hull can present a risk, I would want to make all equipment as accessible as possible to enable in-situ diagnosis, repair, and/or bypass.

Sean

-------- Original Message --------
On Mar 5, 2024, 07:45, Jon Wallace via Personal_Submersibles wrote:

> Thanks for the response James. I found a USA supplier at Dive Gear Express that custom make them as well. I am still pondering whether to bring HP into the hull or put first stage balanced regulators on the tanks and bring in 150psi (or there abouts). I'm not bothered by HP inside the vessel but LP plumbing parts such as manifolds, pipe fittings, and valves are going to be significantly cheaper and more highly available. I'm not sure there's a real winning strategy over the other either way, but if someone wants to try to convince me I'm listening.
>
> Jon
>
> On Tuesday, March 5, 2024 at 09:08:27 AM EST, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
> HI Jon
>
> https://undersea-centre.com/
>
> This is a UK company, but they are really good. Give them a call and tell them what you are trying to do and they will be able to advise.
>
> They made up a pressure reducing manifold for me. I have 2x scuba whips with male din connections both ends. The 2 hoses plug in and via a regulator, are then plumbed into 6mm 300bar swagelok pipe. I will do the same on my new boat, except i probably wont bother with the regulator as i dont really think its required. Will probably just go full HP all round.
>
> Kind Regards
> James
>
> On Sun, 3 Mar 2024 at 18:35, Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>> Where's a good source for HP whip to connect external SCUBA tank to my 1/4 npt hull penetrator? Are you guys using chrome SCUBA whips or hydraulic hose with SS connections?
>>
>> Jon
>>
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