An alternative to scuba tanks is firefighting SCBA tanks. The all aluminum
tanks are rated to 2215 psi in extreme service, doubtless they have very large
safety factor. They are largely being phased out of the fire service in favor
of much lighter and higher pressure carbon over wrapped tanks, which are rated
at 4500 psi, but obviously won't work for cryo.
Additionally, a number of manufacturers offer high pressure gas cylinders in
aluminum, intended for oxygen or nitrogen service. Search for the keyword
DOT-3AL. They are available in a range of pressures and volumes.
--------------------------------------------
On Wed, 12/13/17, ignacio belieres <ignacio_belieres@xxxxxxxxxxx> wrote:
Subject: [AR] Re: Ground Testing Tank Question
To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
Date: Wednesday, December 13, 2017, 1:27 PM
Brian,
I would also recommend splitting the volume into a
couple of tanks instead of just 1, but I really dont think
you could do better than 9k for the setup you need.
Just as Rick has, I too have built a number of both
welded and fastened endcap tanks, with 1200 psi yields and
tested to 800 psi, and I can say this, its not cheap, and it
takes a few tries to get right.
I just ran a quick estimate, and you'd easily be
looking at 5k for the tubing and endcap costs, and another
4k for heat treating. That said, you could probably source
the materials for and build the first tank in less than 1
month.
Another option would be to buy say 15 aluminium scuba
tanks, 22 liter ones, and run them at slightly over their
design pressure. They are usually built with a safety factor
of 4, so other than needing to buy 15 tanks I dont think
there would be any major
difficulties.
Cheers,
IB
-------- Original message --------
From: Rick Wills <willsrw@xxxxxxxxx>
Date: 12/13/17 4:46 PM (GMT-03:00)
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Ground Testing Tank Question
Brian
You can weld up your own
tanks from pieces. The welding will be
tricky due to the thickness you need. An alternative is to
use something like a .5 inch to 1 inch wall thickness then
overwrap the entire tank with
fiberglass with a room temp cure resin. You will need to
set up a winding jig. One problem is this tank will be
heavy so you will need a device (forklift, back hoe, etc) to
move it. Consider using two or three tanks.
Easier to make a smaller tank for these
high pressures.
My tanks
are made with aluminum (6061) cylinder (1/8 thickness) with
hemispheric end caps. We welded and had the welds heat
treated. Yield point is 1000 psi; tested to 750
psi. You could overwrap something like this at
much lower cost and ease of manufacture. You
could overwrap with carbon roving at a greater cost.
You didn’t say anything about temperature ( as in
cryogenic). You could also do a dry overwrap and paint
the resin on the surface.
If you
decide to overwrap, consider getting a used nitrogen gas
bottle and try overwrapping it. Then test to failure.
You need experience in wrapping.
What do you
need such a high pressure for? Most of my work is well
below 1500 psi.
Hope this
helps,
Rick
From:
arocket-bounce@xxxxxxxxxxxxx
[mailto:arocket-bounce@xxxxxxxxxxxxx]
On Behalf Of Brian McCann
Sent: Wednesday, December 13, 2017 10:06 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Ground Testing Tank Question
Hello All,
Trying to find a reliable source
for some ground testing tanks. They can be used or custom
fabricated, but preferably vertical cylinder designs. Trying
to get them with specs of 80 gallon (300 liter) capacity
and pressure rated to 4350 psi (300 Bar). Material wise,
looking at 304 unless someone has a better suggestion. These
tanks do need to be able to handle cryogenic conditions as
well.
I have been looking for a while
and talking with some vendors, but not many are willing to
make only two of these tanks, or they have a lead time of
6-12 months. Ideally, looking for about a 2-3 month lead
time and a price that will not cause my bank to
break.
Thoughts and suggestions very
welcome!
Thank you in advance for the
guidance.
Cheers,
Brian
