[Splave]

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.

[GFDuke]

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.

[Chuchnit]

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.

[Buckeye]

Originally Posted by Chuchnit

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.

Yup sounds like what happened.

The blow off valve might be frozen and stuck open. Try what was suggested with hot water and tapping.

Frezening the Dewar like that when filling can also be bad for the vaccum seal of the main part of the Dewar.

I forget what type/size Dewar you have ?

When they fill mine I take off the pressure top and they drop the hose right into it for filling. Can yours do this ?

Gezz just wake up and only see the first post and a few comments after... must have more coffee LOL


tbh guys the big Dewars you get when renting can be total garbage. First 160L I had from Airgas was junk and was popping off all day and night. Granted it was very hot here when I had it tho. It was a low pressure Dewar and very hard to get liquid out of.

Second one I rented was a 230L and in much better shape, no venting. It was a high pressure tank.
It kept pressure at a nice steady state. The was another valve on the top that you could open which allowed pressure to build back up very fast when I was filling my 50L from it.

I don't think I will fill my 50L from these big tanks next time as I waste way to much gas when doing so.

Did they charge you for a filling hose and defuser at the end for the big tanks ?

[Splave]

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.

[Dentlord]

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.

[Splave]

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

[ReverendMaynard]

Originally Posted by Splave

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.

[HITandRUN]

Originally Posted by Splave

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

If its blowing off thats a good thing. Now I would not worry too much since it will take a little more that 15PSI pop the hood on a dewar. I'm sure something is froze on this thing and will be good as you start emptying it. I think this may be a product of too fast filling by the dude.

[GFDuke]

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