When I researched this a number of years back, both Taylor-Wharton and
Cole-Parmer techs said nearly all dewar failures were in the epoxy in the neck
of the dewar. This could not be remedied through pumping down the vacuum
jacket as the seal was breached.
They did give some advice to elongate the lifespan of the dewars:
1. try not to raise the liquid level above the bottom of the inside of the
neck.
2. do not drop the dewar.
3. try to keep the dewar temperature constant and thaw it only when necessary.
4. keep the cap on to maintain temperature in the neck.
5. do not apply extreme heat to the inside of the dewar, especially at the
neck.
6. purge the dewar with dry gas (nitrogen) until dry.
Realize the absorptive material inside travel dewars will need additional time
to dry.
Additionally, if you wish to thaw your dewar more quickly, tilt the dewar on
its side (or even angled more) to allow the cooler, more dense air to fall out
as warmer air is pulled into the vessel.
Kris
________________________________
From: Gunnar Olovsson <gunnar.c...@gmail.com>
To: CCP4BB@JISCMAIL.AC.UK
Sent: Wed, June 30, 2010 5:20:47 PM
Subject: Re: [ccp4bb] vacuum adapter for Dry shipper Cryo Dewar
Thank you everyone that replied !
I got some excellent answers!
Cheers! Gunnar :^)
On Tue, Jun 29, 2010 at 3:32 PM, James Holton <jmhol...@lbl.gov> wrote:
>
>
>
>
>
>>The part you are looking for is known as a "valve operator", at least
>in the parlance of our supplier. Here's a cut & paste of the item
>we purchased for pumping out our shipping dewars with a nominal 30mm
>O.D.:
>>************************************
>>V1000 Series Operator for 1" tube.
>>Part Number: V1085-3-25 (KF-25 flange) @ $356.00 each
>
>>From:
>>DLH INDUSTRIES INC.
>>P.O. Box 562
>>San Luis Obispo, California 93406
>>(805) 781-3565 FAX (805) 781-3566
>>Email: sa...@cryocomp.com
>>Web Site: http://www.cryocomp.com
>>******************************************
>
>>So far, we have tried to rescue 3-4 different people's dewars by
>pumping them down with this thing, and only one of them has worked.
>Most of the time the vacuum fails because of a crack or leak on the
>inside of the dewar somewhere, and that cannot easily be fixed. Still,
>the one success pays for the tool.
>
>>-James Holton
>>MAD Scientist
>
>
>
>>On 6/28/2010 9:34 PM, Frank von Delft wrote:
>
>>>
>>They seem to have a finite life-time: we had two of these, bought at
>>the same time, self-immolate the way you describe within months of
>>another, after ~5 years of good service.
>>
>>>>We asked TW about it and they said it would cost more to get it fixed
>>than just get a new one -- then again, they would have said that,
>>wouldn't they. If you figure out how to re-suck the vacuum, do tell
>>the list!
>>
>>>>Cheers
>>>>phx.
>>
>>>>P.S. Sorry, we don't have an adaptor -- you probably figured :)
>>
>>
>>
>>>>On 29/06/2010 00:07, Gunnar Olovsson wrote:
>>
>>Dear ccp4bb,
>>>
>>>
>>>We
>>>have a Taylor-Wharton CX100 Dry
>>>shipper Dewar that has lost it's vacuum insulation. The vacuum sealing
>>>plug "popped out" of the
>>>valve (standard 30mm diameter).
>>>
>>>
>>>Has
>>>anyone found a vacuum adapter that
>>>fits so that one can re-establish vacuum
>>>insulation at "home"?
>>>
>>>
>>>I
>>>would ideally need to find a vacuum adapter that fits the valve of the
>>>Dewar and that ends in a KF16 Flange (preferably), so that
>>>we can re-establish vacuum insulation ourselves.
>>>
>>>
>>>
>>> Thank you very much in advance for your help!
>>>
>>>
>>>
>>> Sincerely - Gunnar
>>>
>>>
>>>
>>>
>>>Dr.
>>>Gunnar Olovsson
>>>Life Sciences Centre
>>>(4th floor)
>>>University
>>>of British Columbia
>>>2350
>>>Health Sciences Mall
>>>Vancouver,BC
>>> V6T1Z3 Canada
>>>gun...@byron.biochem.ubc.ca
>
