Dewar to the extreme

I

itrade

Joined
Jul 3, 2002
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645
RLinger asked if I got a new tank. Here it is:

tank.jpg


60+ liters, found in a surplus warehouse.

I may not be much of a maker, but my shop is lookin' good.

Steve

(OK I wasn't going to gloat, but only paid $100)
 
Gloat away, that's dirt cheap, and quite a find. That doesn't have a screw-off top, though, does it? Looks more like a storage cylinder from this vantage. Did you get another open-top dewar to put the LN in or something, or am I seeing wrong? I'm just wondering how you'll immerse the blades. Curious, not critical...
 
Impressive.

Missed out this week, but sometime I'm gonna go in with my friend to work whenhe's refilling the LN bottles. Works at a medical research facility as a graduate student, and one of his jobs is to refill the LN. They've got the nice big 6' tall or so cylinders that they fillt he smaller ones out of. I'm jealous. :)
 
(OK I wasn't going to gloat, but only paid $100)

Some people have all the &^*)*_(_)(^%#$#$#@@! luck! #^%^%%$##@ %$$##@#@%^^$$$# and the $##$%^%$@@ you rode in on!;)
 
Gee good fortune breeds hatred ;) ;) :p

fitzo,

You're right it is a storage/transfer unit. I bought it only knowing that, but the for the price I was going to find some use for it. The surprise was that the valve assembly is held in with a single quick clamp. Flick of the finger and it pulls right out (just release the pressure first!). Reveals a 2.5" hole.

I don't know what shape the vacuum is. If it needs service the frieght back to the manufacturer is going to cost a small fortune, but ... So far it's holding ok. The pressure is sitting at 12lbs.

Once in a while luck runs your way.

Steve

PS Found on EBAY - no bidders and they sold it to me after the auction was over.
 
Steve, I think you'll be okay on that tank. You may better serve yourself later on by getting a 20 liter dewar and using this unit to refill the dewar as necessary. You'll need to see how long this unit preserves to LN to know. I had to wait (very happily) 5 1/2 months for my 20 liter dewar to get too low to use. Hopefully yours will last much longer.

RL
 
Hi Steve,

...hate to one up you, but I only paid $40 for a 150L LN2 storage bottle! :) It's waiting in a warehouse up near D.C. for me to pick up next time I head up that way. Heck, I paid more for my 60L dewar ($125)! That's a nice looking set-up you've got there, btw.

-Darren
 
Steve,

That's pretty cool you can take the "lid" off and possibly use it directly for immersion without having to buy a secondary Dewar. I couldn't remember what the configuration was on the storage tanks. 2.5" will accomodate a heckuva blade. I take it there is a vent other than through the dip tube?? Looks like there are a couple of different ports on there.

I hope the vacuum is intact; they don't go bad too often. I was checking on pricing on those yesterday, and they are expensive beasties. You got a great deal. Happy for you. I recently found some Dewars locally, salvaged from my own company. Brand new in the box, and less than a year old, I paid out the yingyang for it, almost a third retail, but it should be in topnotch shape.

Have fun.
 
fitzo,

Good thing you found one. Full retail is outragous!

I am worried about the vacuum tho. The tank was built in '94. An I don't know about service in-between. Heck I don't know how often they are supposed to be checked.

I'm calling around the gas places to find someone in town that re-evacuates them. Only rumors so far.

Just 'cause you're curious. The are 3 valves on top. They all enter into the same cap: filling, liquid, and gas release. These all have simple steel pipes that go inside. Also in the cap is are 2 fittings that hook to a steel coil that makes about 4 loops around inside that top shroud you see. Who ever had it before re-connected with a short nylon 1/4" hose. It makes it real easy to lift the cap off (don't have to disconnect the coil. I'm not sure what the coil did. Maybe keep the top of the tank cool? It's not part of the pressure release valves. Those are hooked into the pipes. Hmmmm.......


This morning the pressure is at 12lbs and the release valve is releasing. I wonder how much 'release' is normal in a proper dewar of this type. Regular dewars have a foam plug with slits to allow the release. I suppose, since I'm not draining, I don't really need the valve assembly and could use a foam plug if that works better?? The drain pipe goes to the bottom of the tank and up to the valve. Seems to me that it would work to draw out the cold? Oh, I don't know.


Steve
 
Steve,

I might suggest looking that model up through the manufacture's website if they have one. Find out what the evaporation rate is supposed to be and keep a check on it. Or call the vendor about it.

Unless you have a reason to doubt the vacuum I would expect it to be okay.

RL
 
Thanks Roger,

I did call the manufacturer before purchase. It was a custom order and still had the paperwork. They never tested the evaporation rate, but he figured less than .25 liters a day. (.2 a day is 1 liter in 5 days. 40 liters in 200 days I think I can expect an easy 6 months life out of it.)

I didn't know about the coil at the time to ask.

Of all things I forgot to ask the actually holding size!

Steve

PS This is all your fault, Mr. Doyouownheattreat ;) ;)
 
I wonder if that coil and fittings are for heat exchange? Could it be there to run warm water or a gas through to keep the valve from freezing when there is a steady flow on the gas outlet line? i know CO2 tanks for MIG welding can actually freeze the valve if there's too much flow. Or simply to prevent moisture condensation as the gas cools the valve?

I read yesterday on a safety website for these things that LN can actually freeze oxygen out of the air when a condenser is cooled with LN. That was sorta freaky. I also read that, for another manufacturer, leak rate on their cylinders was 2.8% per day.

I betcha still have a good tank. We had the same tanks for years in some cases at work and never had one go bad that my feeble mind can remember. As for release when filled, they hissed constantly.

Seems to me you got a real winner at an awesome price.
 
I agree. A real super buy. I just love the looks of it. It looks soooo important. Steve's going to be a heat treat'n man.

RL
 
As for release when filled, they hissed constantly.
Click to expand...

Yeah - thanks Mike! That little piece of info goes a long way.

RE the coil

The both ends of the coil definately open into the cap, which is open to the chamber.

So, you haven't seen that before. Hmmmm....

I could call the manufacturer but that would ruin the mystery.

Steve
 
This coil thingy is intruiging. Almost sounds like the pigtail on a steam guage to prevent hammering.....
If you find out what it is, please post. Thanks.
 
Whoa!

Man Steve, you sure scored! That is awesome. I've been watching dewars off and on for a while (same durned influence, too... :D ) but have never seen such a fine deal. That's what clean livin'll getcha!

Keep up the great luck!

Dave
 
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