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Date: Thu, 30 Nov 1995 07:28:59 -0500 (EST)
From: Ken Sallot <afn35346@af*.or*>
To: Jason Rogers <gasdive@sy*.DI*.oz*.au*>
Cc: techdiver@terra.net
Subject: Re: Spare Air/Pony (was manifolds & inde, was trimix bailout)
On Wed, 29 Nov 1995, Jason Rogers wrote:

> With an independent system (be it in cave or OW) other peoples mistakes
> won't do you in.

Follow rule #1, that should solve this.

> Those figures were based on *one* disk failing in a manifolded set.
> The pressure remaining, was the pressure in both cylinders and the
> time was the time to closing the isolation valve.  Then the
> pressure remaining was the pressure left in the cylinder with the
> "good" disk. The other one will drain to nothing, and there is no
> way to stop it.
> 
> I mentioned two holes because there are two types of burst disk plug
> in common use.  I measured, and did the figures for the one with the
> *lowest* flow.  The *single* hole plug.  These are now falling into
> disfavour due to liablity concerns with cylinders flying around when
> the disk goes.  They are being replaced with "reactionless" plugs,
> which have *two* holes in each plug (nothing to do with there being
> two plugs in a manifolded pair)  This type of plug will flow twice
> as fast as the older single hole type, because it has two holes!

Once again, how long does it take to dump the contents of a tank through 
a burst disk. Really. The ones I've seen do not go in "10 seconds" (even 
though with all the damn noise they make you wish they did). Now down 
below you offer to blow $100 worth of trimix.. That does open one 
question, which this is pure ignorance on my part, does trimix dump 
quicker because of the lack of gas density compared to air? 

> > Jason, next you'll be telling me you want to do trimix fills based on
> > a set flow psi over <x> minutes ;-)
> >
> Isn't that how ANDI mixes NTX?  ;)

That explains a lot about the "safe air" campaign...

Ken

--
==================================================================
Ken Sallot        "Your trim goes to hell when you run out of air"
afn35346@af*.or*                                         - Jim Wei
http://grove.ufl.edu/~ken/

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