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[How To] Renewal Dewar Vacum


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Guest barbonenet
Posted

U r welcome;) just for confirm that the guide works properly, after a year my dewars have still perfect vacuum;)

 

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Posted (edited)

Thanks for this bro ,I'm thinking about little maintenance on both of my tanks since they aging quick ..looks like techjesse have similar valve seat

Edited by coolhand411
  • 8 months later...
  • 1 month later...
Posted

So you think i can still do this repair? In the valve there is a steel ball that is able to spin. Looks different from other dewar's so im not sure how to do it. Would it be possible to just seal that valve and drill a new hole to use as the valve port?

Posted

I saw that Drweez had / has similar dewar with a ball bearing in it. Guess i could pm him for some advice on how to get it out.

 

http://forum.hwbot.org/showthread.php?t=144929

 

Thanks for the guide.

 

Side question :)

im pretty sure if i were to drill another hole on the dewar that it would ruin it because the is some kind of material inside the vacuum chamber? Is that why i have to go in where the valve is?

Posted

Just a tip for others. don't buy the same dewar i have ( union carbide LR-31 linde)

 

(Thank you for your inquiry but we no longer repair this type of vessel.

Success rate was 50% at best as the glue joint is the most common failure

point. Even if we were not able to perform the repair successfully you

would be liable for $125.00 as it would be necessary to weld a pump out port

on the dewar in order to leak check it.)

Posted
I saw that Drweez had / has similar dewar with a ball bearing in it. Guess i could pm him for some advice on how to get it out.

 

http://forum.hwbot.org/showthread.php?t=144929

 

Thanks for the guide.

 

Side question :)

im pretty sure if i were to drill another hole on the dewar that it would ruin it because the is some kind of material inside the vacuum chamber? Is that why i have to go in where the valve is?

Because if u make another hole, u will have the double problem of air infiltration...u need to work with that hole....is a bit harder but u can do it

 

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Posted

I'm going to bring it to this welding / metal fabrication place I talked to today. There going to help me out with it.

 

Took a little explanation but he got the jist of what I wanted to do.

 

Thanks for all the advice much appreciated.

 

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  • 3 years later...
Posted

I have repaired two dewars this way and the performance is great. My valve that I use is not the most suitable one for vacuums but it still works. I recommend you use boiling water to heat the inside part of the dewar to like +80c or so for better performance.

 

 

  • 2 months later...

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