Extreme Pressures and Cryogenic Fittings/Materials 1

[karlb]

Looking for suitable material/fittings. From what I've seen Cryogenics typically involves low pressure. This is involving high pressures. This is not the actual application but does cover the range of requirements.

Essentially, I want to fill a small custom cylinder (1" ID approx) temperature pre-conditioned and with suitable wall thickness with LN2 at 100K. I then would like to seal the cylinder with a fitting/plug and allow all to warm to room temp. Essentially I should still have the same density of gas as I had with fluid when at room temp.

Does anyone have some thoughts on best method of filling and if there are fittings available to cover this range of temp & pressures?
I am concerned that fitting and cylinder work through the entire range and I also haven't figured out at what rate this would occur.

I would like to use 6061-T6 for cylinder but not at 1000 atm. I've looked at Inconel625 and a few others as a start.

I have found this forum to be a great source when considering a new application. This is also a new discipline for me, one which I have no experience in.

Much appreciated.
KB

 

[dcasto]

go to the NIST web site and see if they have data on N2 over 30,000 psi as it will take over that pressure to get the densities the same.

 

[EdStainless]

625 may be a good option. I can 't think of any high strength age hardened alloy that I would use at LN temps.
The cylinder isn't a big deal, but a closure that works at 30ksi is another issue. And you will need a valve........

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Plymouth Tube

 

[iainuts]

Cone and thread type fittings and valves such as from Butech are acceptable down well below LIN temperature and can go as high as 100,000 psi or more. Valves are also available with extended stem for cryogenic applications.

 

[karlb]

Hello again,

Thanks for the input...I've done some calcs and my application seems reasonable but now I'm considering the design of fluid handling and filling apparatus.
I am a little worried about procedures also as this will be disconnected from the filling apparatus.

Can anyone provide some design and set up advice?

Are there similar applications in industry?

Cheers,

KarlB

 

[HDS]

Not very similar pressure or temp but liquid natural gas and propane tanks are filled with a liquid gas and kept at pressure to keep the gas a liquid. Pressures are only 3600psi.

Be careful of phase change in your metals for the cylinder. Make sure you look at properties at 77K and consider thermal shock and fatigue.