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RE: [PSUBS-MAILIST] Fill Rate & Blow Rate
Very good questions! There's no way to over pressurize the MBTs, they
have no bottoms. I suppose it would be possible if you had one with
small openings, but these literally have no bottom at all. Regarding the
possibility of a 3,000 psi air leak into the cabin, yes that is
certainly something to take into account, and I think it's in ABS
somewhere. Here are the mitigating circumstances in Snoopy, some on
purpose and some accidental:
- There's a cabin overpressure valve. I'm not referring to the ball
valve you would use to flood the cabin for bailing out. I mean a
separate spring loaded valve that automatically relieves any cabin
pressure buildup. I've noticed folks like Emile and Carsten do the same.
This is a must for me, with regulated or unregulated air. While a major
leak at 3,000 psi might be very rare, slow leaks are relatively common
and can also build up pressure over time unnoticed. If you aren't aware
of it you can blow a viewport or hatch during surfacing. Recall the
incident related by Kittredge in his biography.
- There are hull stops on the HP lines, and they only require a quarter
turn.
- The tubing is 1/4 inch and the heaviest wall available. Therefore the
bore is quite small.
- I'm partial to small SCUBA tanks, and the largest I own is a 63 cf.
The cabin volume of a K250 is 40 cf. So even if you dumped the whole
tank into the cabin, it's not like you'd knock yourself out with a
pressure increase of hundreds of pounds.
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Alex
Sent: Thursday, April 19, 2012 2:06 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Fill Rate & Blow Rate
If you did have a ball valve or even a normal valve and you opened it
suddenly,
could you over pressurize your soft tanks and blow them out?
Now that got me thinking. If you had a valve or pipe failure and the
3000 PSI
tank air went inside the psub, could the pressure inside blow out the
hatch or
dome once you got to the surface, or worse, before you got to the
surface and
cause injury and flooding?
Alex
On 19-Apr-2012 Smyth, Alec wrote:
> Yes, that's correct. The thing is, you don't do it with a ball valve,
> you use valves that graduate more finely.
>
>
> -----Original Message-----
> From: owner-personal_submersibles@psubs.org
> [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Jon
Wallace
> Sent: Thursday, April 19, 2012 11:37 AM
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] Fill Rate & Blow Rate
>
>
> Alec, I want to make sure I understand...you're running straight
piping
> from HP tank to ballast tank and just using an appropriate sized valve
> someplace to let the air pass to the ballast tank. With valve
> completely open you're supplying 3000psi (with a full tank) into the
> ballast tank. Is this correct?
>
>
>
>
>
>
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--
Mailed on 19-Apr-2012.
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