Re: [PSUBS-MAILIST] RE: payload

["Paul Kreemer" <paulkreemer@gmail.com>]

The LP taps should give you just 140-150psi.  (http://www.scubadiverinfo.com/2_regulators.html)  That'd about equal the ambient pressure at 330ft.  So the deep tech divers must use adjusted first stages to go as deep as they do.  ??

Paul

On 12/10/06, Joseph Perkel <joeperkel@hotmail.com> wrote:

"The pressure in a scuba tank is much greater than what we'll get in our
trim tanks"

.........Does a 350' rated psub use HP air directly off the tank valve, or
thru an LP port on a second stage to blow soft tanks? Someone please remind
me what psi service is in an LP port? A quick google came up empty.

Joe

>From: ShellyDalg@aol.com
>Reply-To: personal_submersibles@psubs.org
>To: personal_submersibles@psubs.org
>Subject: Re: [PSUBS-MAILIST] RE: payload
>Date: Sun, 10 Dec 2006 13:26:47 EST
>
>NP- You are right, the psi is the same. The mechanical advantage does apply
>with a decrease in volume though.
>The analogy of a square, one inch rod, pushing into the sub's one
>atmosphere
>gives you a certain pressure, where as a 1/4 inch round rod ( or hose  )
>would push less.
>Still, to push something out of the sub ( like ballast water) will require
>a
>pump able to push the 267 psi.
>Depending on the volume pumped,  267 psi is easy to achieve, and in  the
>case
>of a trim tank, you're pumping air into a tank to expel the  water.
>I've got a small compressor in my vehicle for emergency roadside repairs
>that pumps to 250 psi ( but at a very small volume ) that runs on 12
>volts.
>The pressure in a scuba tank is much greater than what we'll get in our
>trim
>tanks.
>Blowing out the trim ballast ( adjusting trim en route ) must be part of
>the
>system or we'll have to surface constantly to dump the water.
>Frank D.
>





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