Got a 180L today. Arrived at 150 psi. I drained 25L out of it to fill up one of my dewars so I woudn't get stuck without LN2 unexpectedly. About 7-8 hours later the thing was popping off at 350psi every 5-10 minutes.

The liquid removal port valve was stuck so I couldn't drain it (not frozen at all). I opened the vent valve and the sucker took 1/2 hour to get the pressure down to 0!

After some effort and some assistance from channel locks, I got the liquid valve to open.

Closed the vent and waiting for pressure to build up again.

Makes me nervous to have a damn bomb sitting in my garage popping off at 350psi every few minutes.......it's loud too.

Is this normal? My last 180L rental never popped off. (Of course, it was gone in a few days........was more like an 80 L rental...)

Yikes, I'd be friggin nervous too, especially after seeing what it does to a sealed water bottle

WTF?

I would call and complain. (after you top off another dewar ;))

send it back to the supplier and dont pay for it, stress the fact that you requested (ordered) a low presser NL55 22PSI

the high pressure tanks are for gas withdraw only, you are only after the LIquid

the blow off is normal for high pressure tanks, even low pressure tanks will blow off occasionally. no danger here tho

what is the model of your tank?

Ahh....therein lies the problem.

I go through a mom and pop welding supply (1/3 the price of airgas and praxair in my area). I'm pretty familiar with their yard, and haven't seen any other dewars (unless the 230 L's are lower pressure). They normally have 1 to 4 LN2 tanks around. These high pressure tanks are what they fill my personal dewars with.

The 350psi is where the popoff is supposed to occur - but I got concerned with the rapid rise from 150 to 350 and the frequent loud popoffs in my garage. The last time I rented one of these, it never popped off and it hung out at 250ish psi.

Thank you sir! Methinks I'll have to go back to just bringing my dewars to fill if I can't arrange a lower pressure dewar through them. I'm skeptical about them investing in alternative equipment just to tailor to me.

all the tanks are the same only the regulator just needs to be dialed down (only time here) and the bleed off needs to be swapped ($15 part)

explain your situation and they should know what to do.

im betting they are getting supplied from AIRGAS any ways, in that case the tank will be swapped out as im sure they rent them :D


when you go with a low pressure tank (22PSI bleed) you will be able to withdraw much more liquid so it is by far a better deal

:thumbsup:

Great info.

Filled my dewars today and the guy tells me I have the biggest dewar he's ever seen (50L) :Dizzy:

"Who hit the fucking mustang"
:laughing:

Brian@asus Travis and I were messing around with extra ln2 the last night. I put some in water bottle that had the spouted top and shook that bitch and the cap went flying maybe 60 yards and supposedly pinged one of the prize mustangs. Guy with a beard comes over to yell at us. :laughing: