Dear All,
Thanks for the response.
For those of you interested, the extra cost associated with shipping
'wet' is about 35 USD within the US, and about 50 to 100 dollar
internationally. Extra paperwork and labels are needed when shipping
wet. One of our users recommends shipping wet, especially
internationally. in the case that something does go wrong (customs,
dewar lost), your samples should still be okay.
The best procedure for preparing a dewar for dry shipping seems to be
the as described by Steve Ginell:
all shipping dewars are turned upside down until all LN2 drains out,
this is repeated 2-3x times to remove the residual caught in the top.
Summary:
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At APS/SBC sector 19 all shipping dewars are turned upside down until
all LN2 drains out, this is repeated 2-3x times to remove the residual
caught in the top. With this method there is no free LN2 remaining in
the dewars to leak out. During the upside down tipping the dewars must
not be bumped. The ANL shipping Department has been instructed to
verify that the dewars are empty of LN2 by turning them upside down
prior to shipping. When pucks are not used we caution all users to
place vials securely in the dewars using canes with tabs or placing
the bottom of one against the top of another and using plastic
sleeves, to prevent the pins from being dislodged from the vials.
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We tip them out thoroughly ahead of time and by the time the Dewars ship
there's never any liquid in them. (....) if you absolutely MUST have
the vessel to be entirely dry it
is adviseable to empty the Dewar and wait 5-10 hours before shipping it.
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Personally I drain the dewars before filling (...) Then I fill the
dewar with canes and make two attempts to tip/angle the dewar to drain
off nitrogen without losing the vials. (...) There is one group in our
department that likes (or liked) to ship "dry" dewars as "liquid"
(with all the paperwork and hassle that you can imagine) because they
had the same experience that you describe (...)
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SSRL always ships them back full. We even had our shipper temporarily
denied by FedEx because we forgot to
remove the ssrl label specifying that there is liquid nitrogen inside.
So in theory one can arrange to ship dewars *with* liquid nitrogen.
We usually just tilt the shipper (we have Taylor-Wharton CX100) at
roughly 150 degrees polar angle with respect to its upright position
and
hold it like that until no liquid is coming out. We never had a
problem with FedEx.
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I always used to just fill the shipper w/ LN2, and declare it
Dangerous Goods. Never any trouble, save one time in Birmingham (AL),
the FedEx person at the office intentionally tipped shipper 90
degrees, even though it was marked DG, Keep Upright, etc. !!
Naturally, they got scared by all the "steam" and hissing! I went down
the the FedEx office, and easily convinced them not to tip it (after
all, it was marked DG!), and all was then OK. I guess the goal of
"dry" shipping is to save the DG costs. On this I cannot comment,
other than one potentially good, but ruined crystal to me is worth
more than DG shipping costs (which, as I recall, only add ~$100-200).
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Thanks a lot.
Peter Zwart
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