The dry dewar is employed to transport target materials at LN2 temperature (77K). In practice, the dewar doesn't contain LN2 directly; rather, it employs an absorbent to saturate and maintain the LN2, thus preserving the target material at LN2 temperature. Prior to usage, some prerequisites should be observed: check for vacuum integrity, inspect for leaks, invert the dewar to ensure no LN2 flow, and fully charge the dry shipper with LN2 until no LN2 escapes.
To verify if the dewar is fully charged:
So, the total dewar weight is the sum of the empty Dry Shipper weight (11.7 lbs) and the absorbent holding 4.1L of LN2 (7.30 lbs), resulting in a total of 19 lbs.
Here are some important information that we used to write up the document for dry shipper to ship CH2/CD2 and NH3/ND3.
We received documentation from Vendors to prepare dry shipper. K SERIES Cryostorage System.pdf
We received W.E.Sander letter of Compliance for dry dewar. UVa dry Dewar compliance evaluation 13sep2023.docx
49 CFR ยง 173.320 - Cryogenic liquids; exceptions (https://www.law.cornell.edu/cfr/text/49/173.320#:~:text=(a)%20Atmospheric%20gases%20and%20helium,temperature%20conditions%20during%20transportation%20are)
These pictures were taken during the drop test of the shipper case at UVA. The dewar shipper and plastic box were dropped from a height of 1.8 meters
one time from every direction with LN2 absorbed in the dewar. No damage to either the box or the dewar was found. A weight test was performed with
the equivalent weight of 10 ft of the same package stacked on top of the dewar box. The required weight is 130 lbs so six 25 lbs lead bricks were used for
a total of 150 lbs. The weight was left on top of the box for 24 hours with no damage to the external box or filled dewar inside.
