Re: [PSUBS-MAILIST] propane tanks revisited

[irox <irox@ix.netcom.com>]

I can't speak for the type of steel used, but I was refering to 'quality' and defect
rate.  Believe there is a difference in the standards used for constructing pressure
vessel for human occupancy compared to the standards used for producing
pressure vessels for propane occupancy.

A defect or flaw that would be acceptable for a propane tank would not neccessarily
be allowed for pressure vessel for human occupancy.

Ian.

-----Original Message-----
From: Brian Cox <ojaibees@ojai.net>
Sent: Apr 30, 2004 12:13 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] propane tanks revisited

Ian,  I don't think that the steel used for internal pressure is different than that for external pressure.

Brian
----- Original Message ----- 
From: "Ian Roxborough" <irox@ix.netcom.com>
To: <personal_submersibles@psubs.org>
Sent: Friday, April 30, 2004 8:29 AM
Subject: Re: [PSUBS-MAILIST] propane tanks revisited


> 
> There's a lot of stuff in the archives about propane tanks, and I seem
> to remember that you still have to deoderize a new tank due to some
> chemical that is used to treat the inside.
> 
> Propane tanks are designed specifically for internal pressure, you are
> building something that's specifically designed for external pressure.
> (Internal pressure vessels are more forgiving of defects than external
> pressure vessels.)
> 
> Still, if you're going this route, then a new propane tank is going
> to be way better than a used (unknown quality) propane....
> 
> Ian.
> 
> On Fri, 30 Apr 2004 07:30:00 -0700
> "Brian Cox" <ojaibees@ojai.net> wrote:
> 
> > Propane Tank investigation:
> > 
> > I was explaning my design to my diving friend and he mentioned that
> > since my pressure hull is around 28" in diameter that I might consider a
> > propane tank.  I have always discounted the propane tank idea because I
> > felt having to deoderize it wouldn't be worth the effort, but then we
> > discussed buying a brand new one -never been used - from the factory.
> > I didn't think that would make any difference whether you were buyng a
> > new one from the factory or having one rolled from a fabrication
> > lant  -  but  -  he pointed out that since the propane tanks are mass
> > produced that they are cheaper !  So I called a propane company that I
> > know and sure enough they are a lot cheaper .  For a 250 gal  which is
> > approx 30" X 7'  the cost was $850.00    compared to $2000.00 (a year
> > ago) having it rolled at a fab plant.  I still have to find out the
> > exact specs on the propane tank however,  I'm not sure on the thickness
> > and I haven't confirmed the grade of steel.
> > 
> > Brian
> > 
>