[3dem] issues with liquid nitrogen tanks

[Matthias Wolf]

Hi Kristin,

I doubt you have crappy tanks. Your supplier probably occasionally overfills them. When a tank is filled all the way to the top, there is no gaseous N2 to push out the liquid. In that case simply open the valve opposite of the LN2 valve for a limited time to generate pressure. Once there is sufficient volume of N2 on top, it becomes self-propelling.
It may help with your setup, if you  swap only one of the two bottles at a time, so that the half filled one provides enough pressure.

Matthias
________________________________
From: 3dem <3dem-bounces at ncmir.ucsd.edu> on behalf of Parent, Kristin <kparent at msu.edu>
Sent: Wednesday, January 29, 2020 07:21
To: 3dem
Subject: Re: [3dem] issues with liquid nitrogen tanks

Thank you everyone for the great suggestions!!! We have some things to try here and I hope it will get resolved easily.

Best,
Kristin

From: 3dem <3dem-bounces at ncmir.ucsd.edu> on behalf of "Parent, Kristin" <kparent at msu.edu>
Date: Tuesday, January 28, 2020 at 2:45 PM
To: 3dem <3dem at ncmir.ucsd.edu>
Subject: [3dem] issues with liquid nitrogen tanks

Hello fellow 3dem-ers,

We are experiencing quite an annoying situation with Airgas and I am wondering if other folks have had similar problems and what potential solutions are.

We have a custom manifold from Chart to deliver liquid nitrogen to our Talos Arctica that can be equipped with two 240L tanks, each with 22 psi pressure. This should help reduce the LN2 waste and be more efficient, and when our tanks are good, it really is amazing. BUT, some of the time Airgas gives us tanks that we cannot use as the pressure never builds beyond 10 psi and we have to return full tanks. They are not the nicest about this either ☹

We know the manifold is working correctly, and that it is caused by individual bad tanks. Has anyone else had crappy tanks? Do people just buy their own tanks and have them refilled instead of swapped?

Unfortunately, in Michigan Airgas is our only option, so any help would be appreciated.

Thanks in advance,
Kristin

--
Kristin N. Parent, PhD
JK Billman, Jr., MD Endowed Research Professor
Director, MSU Cryo-EM
Associate Professor of Biochemistry and Microbiology
Michigan State University
603 Wilson Rd
East Lansing, MI 48824
Phone: 517-432-8434
https://kparentlab.natsci.msu.edu/
Twitter: @Phage4Lyfe

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