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Re: [PSUBS-MAILIST] Ambient Pressure (No Subject)
Hi Brent!
Thanks for the letter. You have some very solid points I haven't tought.
I was planning to have the sub just slitely negative with ballast full of
water so the descend will be very slow. No problem since I plan to go at
about max 60 foot.
Very good idea about the check valve! I would have to check the outside
pressure because my design can't resist pressure. I think I will install
those two gages.
The supply of air is a 3/8" dia line with the ball valve at 100 psi. I think
it can supply enough air for the dive.
I'm not too hot to relie on a automatic valve because of the poor pressure
design of my hull.
Thanks again for the advise! How is your project gooing?
Pierre Poulin
>From: Brent Shaw <drydivenz@yahoo.com>
>Reply-To: personal_submersibles@psubs.org
>To: personal_submersibles@psubs.org
>Subject: Re: [PSUBS-MAILIST] Ambient Pressure (No Subject)
>Date: Tue, 25 Mar 2003 14:07:56 -0800 (PST)
>
>Pierre
>
>After reading this I believe you could be heading for
>danger and not being able to enjoy the scenery because
>you'll be working to hard.
>
>What I see as being dangerous is if any water comes
>into the hull, displacement changes and the sub will
>go down. Watching a clear hose I think would not be
>the right way the control of inside hull pressure
>although it would work and is very simple.
>
>Driving along in your sub you'll be constantly turning
>ball valves on and off as well as steering. I see that
>as a lot of work and any little slip up and you could
>crash.
>
>Just my two cents worth and I'm no expert
>
>On the hose going out of the hull run a one way check
>valve.
>
>For air into the cabin run a 1/4 push air switch.
>These 1/4 air switches run 900 liters per minute
>@100psi
>Or you could go for a polit operated regulator to make
>the system automated.
>
>Run two 60psi gauges. one for outside hull pressure
>and the other for inside hull pressure.
>
>I would also go for a flow meter. Comments about
>surfacing to refresh the air don't gel right with me
>at all.
>
>
>Brent
>
>
>
>
>
>
>
>--- David Buchner <buchner@wcta.net> wrote:
> >
> > On Monday, Mar 24, 2003, at 19:40 US/Central, Pierre
> > Poulin wrote:
> >
> > > I only have a hole at the bottom of the sub with a
> > ball valve and a
> > > piece of clear tubing that goes to the top and
> > down to the bottom of
> > > the sub. The end of the hose is open-. I also have
> > another ball valve
> > > that provide compressed air from a cylinder into
> > the hull. So the
> > > principle is very simple. If there is not enough
> > air comming in the
> > > sub to equalize the pressure, water will want to
> > go into the sub by
> > > the clear hose. I will see it gooing up and I will
> > open the compressed
> > > air valve to augment pressure inside the hull. If
> > there is to much
> > > compressed air comming in the hull, I don't care
> > because the excess
> > > will go out by the hose. The end of the hose is at
> > the bottom of the
> > > sub to expulse water that might comme into the sub
> > and to expulse co2
> > > which is heavyer that o2.
> >
> > That's the sort of simple way I might have come up
> > with. But (and,
> > apologies if you've described this more in the past
> > and I forgot) --
> > does this arrangement respond fast enough during
> > descent and ascent? I
> > guess: how big is that clear hose? What if you're
> > rummaging in the
> > cooler behind you for another beer, and your shirt
> > sleeve catches on
> > the dive plane stick, and you start ascending
> > rapidly -- is there a
> > danger of higher pressure building up inside because
> > you're rising
> > faster than the air gets out through your tube?
> >
> > - - -
> >
> > David
> > buchner@wcta.net
> > Osage, MN, USA
> > http://customer.wcta.net/buchner
> >
>
>
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