Filling a hand dewar with liquid nitrogen at the ALS

[TheSweetalchemist]

should the pressure builder knob be turned on at the same time when you are getting liquid nitrogen?

[drmcmartin]

It sounds like your liquid nitrogen is boiling off before it gets into your smaller container. Perhaps the flexible hose you're using isn't properly insulated (i.e. if it is vacuum jacketed the vacuum in the hose jacket might be bad). In this case the liquid will mostly boil away just going through the transfer tube and only gas will come out of the end. If your transfer tube is properly insulated, you should start to see liquid coming out of it after a couple minutes.

[TheSweetalchemist]

I have a 180 liter Large Dewar Tank. It's 22 psi. How come after 5 minutes I only filled a cup? And the smoke just fills 1/4 of the room I can't see how much liquid nitrogen I have.

[TheSweetalchemist]

I would appreciate any information on withdrawing liquid nitrogen on a 180 liter tank. I use a flexible hose to get liquid nitrogen. My problem is I cannot measure on how much liquid nitrogen I already have because I cannot see with all the smoke coming out of the hose. If you know any info on how to know have the right amount, I thank you in advance. Most of the time, I thought I already have enough, closed the valve, end up with just a cup.

[TheSweetalchemist]

how do you prevent the larger dewar from making this 100 decibel noise when it releases pressure out its release valve? as this would drive people away

[drmcmartin]

@TheSweetalchemist If the large dewar is releasing pressure out of its release valve on its own, then the dewar needs to release pressure! If this happens often, you probably need to have your dewar checked as it shouldn't be building up that much pressure on its own. If you mean the noise it makes while liquid is flowing down the transfer tube, you can always adjust the flow rate to make the noise more bearable!