Does Size Matter?

D

Dennis Paish

Joined
Jan 3, 2007
Messages
302
Greetings,
I couldn't resist the title...sorry!

What capacity is required for a liquid nitrogen Dewar canister. There are a lot of different sizes and styles of canisters. What to look for, what size (for a small shop) and what to stay away from?

Thanks,
Dennis Paish
 
There is a trade off in longevity between fillups

Larger dewars will hold more, cost more to fill and take up more space
-however they will last longer between fill ups, having more insulation and the larger volume holding it's temp longer.
 
I was quoted today that 10 liters of LN would cost in Calgary, Alberta, Canada $150.00. I could not believe it so I contact the largest supplier here and he verified the same price. They have a 10 liter minimum fill charge. Is that close to what LN is worth in your area?

Note, that Dry Ice is $2.35 cnd per pound. Is that close to what LN is worth in your area?

Thanks for anyone's input. At this point I am heavenly leaning towards the Dry Ice method, based on cost.

Dennis
 
Dennis Paish said:
I was quoted today that 10 liters of LN would cost in Calgary, Alberta, Canada $150.00. I could not believe it so I contact the largest supplier here and he verified the same price. They have a 10 liter minimum fill charge. Is that close to what LN is worth in your area?

Note, that Dry Ice is $2.35 cnd per pound. Is that close to what LN is worth in your area?

Thanks for anyone's input. At this point I am heavenly leaning towards the Dry Ice method, based on cost.

Dennis
Click to expand...


Wow !!! $150 for 10 L. of LN :eek: That seems extremely high to me.

I have a 30 Liter LN Dewar and it cost $126 to fill at Airgas. It isn't a 10 minute procedure. There is an initial fill where the dewar is "cooled down" then it's topped off.

Before I picked up the dewar I used dry ice & acetone with excellent results (per Nathan the Machinist help)(Thanks Nathan ;)) I picked up dry ice for months at less than $2 per lb. Actually my wife usually made the ice run but the last time, I did. I got 15 lbs of dry ice for around $26 U.S. + gas, for ~120-130 mile rd. trip + time.

For me LN, when I take everything into consideration ( & imho, you must) is much more economical.

There is also the option of making your own dry ice. All you need is a syphon tube tank of CO2 and a little gizmo called a frost stick. Do a search on ebay for "Dry Ice Maker". There are several of them plus a couple of commercial looking models being sold right now. I'm not sure how economical this method is as I have not tried it.



:thumbup:
 
jeez,,, $15/L ???? I think I was quoted $2/L (or was it 4?) when I checked some tanks. That seems pretty high.

jm
 
I have only been paying 10.00 us for 30 liters of couse I made the guy who works there (a fellow knife nut) a small cable knife.
 
Bill Burke said:
I have only been paying 10.00 us for 30 liters of couse I made the guy who works there (a fellow knife nut) a small cable knife.
Click to expand...

Thats a really good price Bill. When I initially started checking on LN cost I read somewhere on the web that LN is cheaper to make than bottled water. :confused: Estimated per liter cost's I found (again, somewhere on the web) were less than what I paid too.

Dennis, could the $150/10 L. price you were quoted have something to do with where you live ? Are you even further out in the boondocks that I am ? :eek: As far away from a LN depot as is globally possible maybe ?
 
Part of it is where you are I am sure. The closer you are to a air plant the cheaper it should be. Plus, there are some huge markups on some of this stuff to the guy off the street. Places like welding shops get big discounts. Funny thing, I got a big price break on my personnel supplies, right after I started running a shop and ordering for them. I no longer run that shop, but, still have the discount. Same goes for steel. One of the salesmen for the local steel yard belongs to the same local blacksmith organization as I do. He set me up with my own account and it comes with a big price break. Love that networking. Jim
 
After 2 hours on the phone I found a medical supply company whom will sell LN for $3.00 per Liter with a $10.00 delivery fee. Not bad considering the $15.00 per l quote from all other suppliers in the area.

Question: Do dewars wear out over time? How old is too old?

Thanks for everyone's comments.

Dennis
 
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