Hi Stephen,
We just went through a training session by Oxford Engineer for cryogens
refill. We learned a lot in the process. I highly recommend it as a general
refresher.
Using the rubber boot on the outlet of the He storage Dewar is fine. The
brass fitting between the He storage Dewar & rubber boot can be requested to
the He supplier (Airgas for e.g.). The plastic fittings on the other end of
the rubber boot can be provided by Oxford, or Varian, or Pfeiffer.
Hope this help,
Hélène
Best Regards,
Hélène
Dr. Hélène Citeau
Scientific Instruments Specialist
Department of Chemistry and Biochemistry
Donald P. Shiley Center for Science and Technology
University of San Diego
5998 Alcalà Park
San Diego, CA 92110
Ph.619 260 2920
Fx 619 260 2211
On 3/15/12 7:06 AM, "Stephen Peurifoy" <stephen.peurifoy_at_millersville.edu>
wrote:
> Hello all,
>
> I have a couple of (related) questions about liquid helium fills:
>
> First, there seem to be two general LHe dewar pressurization
> methods. Some facilities use a rubber "boot" on the outlet of
> the transport dewar with a side connection for helium gas.
> Other places pressurize through the dewar vent port. Is this
> just a handed-down tradition thing or are there reasons for
> choosing one method over another?
>
> Second, does anyone know of a supplier for the oddball fittings
> involved in this? The transport dewars we get from our supplier
> have what appears to be a male 3/4-20 UNEF fitting. The female
> nut on our LHe transfer line stinger looks like 7/8-20 UNEF.
> I've trawled the internet for hours and haven't found a source
> for compatible fittings but maybe I haven't used the right
> search terms. There's a 7/8-20 UNEF to 1/2 NPT plastic adapter
> in our "boot" so clearly someone makes these. Our cryogen
> supplier was no help and none of the plumbing places I've checked
> have fittings that size with that fine a thread pitch.
>
> Thanks,
>
> Steve Peurifoy
> Chemistry Department
> Millersville University of Pennsylvania
> Millersville PA
>
>
Received on Thu Mar 15 2012 - 08:27:44 MST