How to build a LN2 Withdrawl Device?

[Buckeye]

It you are talking about that one in the link, it might burst from sudden pressure expansions and being frozen very fast. LN2 expands very fast when it evaperates.

[iandh]

Haha I wasn't suggesting that equipment, more so that a similar design in better material.
Oh and Iandh, I've got a low temp solenoid on the way, we'll have to see how mine plus a PID compares to yours
I think some autocontrol is in the works.

That should be quite swanky... I've daydreamed about an automated dispensation system before. That would be quite handy if you could adjust it to just dribble into the pot and use only what you needed, and you could just concentrate on benching and nothing else.


My design is about one thing only... cheap cheap cheap; that's what I keep hearing repeated about liquid withdrawl devices, how the cost is too high. I do not think that my design is the best way to do it, but I am fairly sure it is the best cheap way to do it.

[Gunslinger]

It you are talking about that one in the link, it might burst from sudden pressure expansions and being frozen very fast. LN2 expands very fast when it evaperates.

One volume of liquid nitrogen will expand to produce 696.5 equivalent volumes of gas.

[Buckeye]

One volume of liquid nitrogen will expand to produce 696.5 equivalent volumes of gas.

LOL yes GS, thats why I said that plastic thing could burst.

[n00b 0f l337]

My design is about one thing only... cheap cheap cheap; that's what I keep hearing repeated about liquid withdrawl devices, how the cost is too high. I do not think that my design is the best way to do it, but I am fairly sure it is the best cheap way to do it.

Might not be that expensive my way either. $100 or so in parts + milling time? $200 product with full automation. Could be half that without automation.

[quintus]

keep going Nol, i started building my own dewar and a withdrawl device will be nice!

[N3RO]

Should have mine here in about 4 days we'll see how it does! Awesome find though even if it doesnt work

And what about if we replace the plastic tubes by another metal tubes?

Maybe works with some mods

[n00b 0f l337]

Naw, I doubt you can replace it all. We'll see, maybe he'll get a run out of it for $4.
I'm trying to work out a pretty universal way to mount the top. It has to be able to withstand 10psi or so, clamp on, and not bolt in.

[n00b 0f l337]

In the spirit of today (invention people! tesla's birthday! come on!)

A low temperature solenoid valve, all metal seals.
Now I just need to pickup a dewar to build a top for.

[k|ngp|n]

In the spirit of today (invention people! tesla's birthday! come on!)

A low temperature solenoid valve, all metal seals.
Now I just need to pickup a dewar to build a top for.

Someone asked me to add to this thread, a simple withdrawl device can be made provided you can find all the parts . I was lucky to get a rubber stopper and tightening nut for it to start with, the rest are just bs parts like the center manifold, 10psi pressure reliefe valve, pressure discharge valve, needle valve for discharge and some stainless flanged tubing.
Most needle valves will work fine for liquid withdrawl device. I have used ones not rated for cryogenic use and they work fine. 40-60.00 range Parker needle valves. Also chart industries used to carry most of the components to make a withdrawl device incuding the rubber stopper, but I havent checked in a few years.

noob, I got a killer 50l cryofab at my shop the has a pressure bulider (for maintaining pressure during LONG periods of valves staying in open postition) and dual parker cryo solenoids with a nice 3/8th 5ft vacuum insulated line coming off from each solenoid for liquid delivery. It's so tight dude
If you want to do any significant benching (multi- component) using valves with an automated or even manual system, you need to have a pressure buliding dewar or one with a busted vacuum seal, the latter actually works awesome but can be VERY DANGEROUS