Quote:
Originally Posted by MaadDaawg
Delivery is never free, and the large dewars gas off real quickly.
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Delivery is cheap though, relatively...
As far as Large containers gassing off more quickly I would expect that.
If you look at the size of 20L dewar the device is much larger that the capacity dictates. teh 160L I saw at teh welding supply shop, were NOT 5-6 times larger than my 30L, more like 3-4.
I am assuming that the ratio of insulation to LN2 is much higher on the smaller units.
So if 1.5" insulation on a 20L say, with a 24" diameter, then move up to a 160L and still have 1.5" insulation on a 36" diameter... im no physics expert but would assume that the larger surface allow greater heat transfer to occur and thus would require a larger amount of insulation...
Another consideration is the large dewars require pressure to dispense LN2 since you cant just tip it...
Pressure = agitated molecules = heat. Might be better to have 3 50L dewars laying around and fill the 160L. Should hold the LN2 better and 30L was easy to pour (one hand pour with another holding my coffee mug
) , cant see 50L being too difficult especially if you have a spout.
just gotta remember it shoot out straight at first lol (I wore a glove the first couple of times, but got it figured out after that and poured from dewar too coffee cup with no glove)
I only have had the experience of 1 full dewar I cant wait to do it again though
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Now that is a piece of copper and anodized alumonum put to good use ...... 
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