Frank:
I read this post first thing this morning, and my brain still isn't in gear, so let me see if I understand this correctly:
I'm in my sub, 600 feet down, and the outside pressure on the hull is 18atm.
(600 / 33) = 18.18atm or 267psi
Now let's say I have three pipes entering the hull, and all three have pressure gauges on them. The first pipe is 3" in diameter, the second is 1", and the third is 1/4" in diameter. Won't all three gages read the same pressure? Will a pump have to generate 267.0001psi in order to pump anything out of the hull?
I think I can understand what you're saying about smaller pumps. A small pump can be geared down so that the volume of water it's moving is decreased while the pressure it creates is increased. It would just take more time to pump out all the water you were trying to move. However, hooking a pump up to a 1/4" hose is not going to give you any more of a mechanical advantage than hooking it up to a 3" pipe... or directly to the hull of the sub.
Am I right? Or should I get a few more cups of coffee in me before I start posting? ;-)
-- NP
From: ShellyDalg@aol.com
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] RE: payload
Date: Wed, 6 Dec 2006 21:30:09 EST
Just a quick note on this pressure thing. If you are pushing against the pressure in a 1/4 inch high pressure hose/line, a small pump would work. Frank D.