Re: [PSUBS-MAILIST] Source for a demand regulator?

[John Farrington <jrf@prismnet.com>]

I've been trying to track down the metal bellows myself, with the
intent of building one of those units myself.

Not knowing exactly which bellows to use, I contacted a manufacturer,
and gave him some ballpark specs on the bellows.  "Approximately 'this'
big in diameter, about 'this' long, needs to move about 'this' far, based
on variations in 'this' much barometic pressure.  Not real specific.

His question back to me was 'How many thousands will you be needing?"

I said about 0.001 'thousand' of them.  We both chuckled.

So, it's going to be a bit of a challenge finding the exact one, at
a reasonable cost.

But, if I can somehow manage to find an off-the-shelf bellows that would
work, then the rest of the unit shouldn't be too difficult to make.

As Phil has said in his paper, it is a simple design that has proven
to be very reliable - nice attributes for your life-support system!

If I make any progress on any of this, I'll definitely post a
parts list to the group.

-John