Dewar blowing off like a mother
 

Alright guys some weird ass guy (not the usual) filled my dewar this morning while I waited. He froze the whole top of the damn thing, blow off valves, handles, gauge etc like im talking half an inch of ice rofl. So the whole time one of my blowoff valves is fully blasting the whole drive to work and i figure it still is. Pressure is at 12psi and the blowoff is 10psi so that makes sense. Does this always happen? I usually drop off and pickup the next day so is this normal? The valve stops when I put my finger over it (which I did so it could thaw out a little bit) Temps are high here today too supposed to be 80s so that certainly doesnt help.

Pour some hot water on it (the blowoff valve) and tap it with a hammer. Thats what i had to do to my 160's from Airgas. Sounds like there is some ice in it.

He coulda damaged the seal on the vacuum by freezing it. That's what my busted dewar does. It keeps too high of pressure and constantly blows off if I put the head on it.

are you fucking serious!
yeah duke I thawed it out real nice tapped it a couple times and it still blowing off from high pressure. There is a 15psi valve right next to the 10psi one, worse comes to worse could I seal the 10psi side?

Is it possible it always does this when it gets filled? pretty sure he left the top on to do it so I could see how it could build some serious pressure if he fucked up.

Mine does something similar to that every time, but only for a few minutes. The whole head is encased in ice after they fill it yeah. All melted off and finished venting by the time I get halfway home (20 minutes)

Like Duke said, sometimes there is ice holding it open and I have to knock it off.

Its sitting in the parking lot of my work lol I will go check it out and see whats going on lol I dont need it exploding on me

hopefully you don't go out and see your car surrounded by bomb squad lol.

Well if its blowing off it wont explode. Its when it dosnt blow off at all you gotta worry. lol

12PSI is awfully low inst the air were you live at 14.7?

(Or are the rated OVER atmosphere?)

must be over atmosphere, and its a 10psi valve says right on it

It was barely hissing when I checked on it so I opened the vent handle for 2 seconds dropped the pressure and it cut off wanted to make sure it wasnt stuck open :) hopefully it doesnt build back up to someting stupid.