Thanks very much to everyone who responded to my questions with so much
great info.
To clarify a little bit, I have the "rubber boot" setup provided by
Varian with our 400-MR, including the low pressure regulator and
gauge and have used it successfully several times. Aside from my
curiosity about the different pressurization methods, my concerns were
that a) I might get a dewar without the knurled nut on top and would
thus have difficulty getting the boot to seal, and b) our boot has a
slight curve to it which tends to put stress on the stinger and makes
it difficult to line up.
A couple of people suggested obtaining the fittings from Cryofab or
RegO. The gold star goes to Michael Strain who jogged my memory
about where I'd seen that plastic transfer tube fitting before.
Michael provided a link to drillspot.com who sell the Parker version
of this polypropylene/polyethylene tubing compression fitting.
I dug around in my spare parts and found a bag of 1/2 inch
polypropylene compression adapters (p/n 5016K466, bag of 5,
available from McMaster-Carr for $7.54). The compression nut side
of this fitting does a perfect job of sealing the stinger to the
outlet of the Cryofab dewar. Same size, same thread pitch. Woohoo!
So to sum up, I may see if I can find a straighter length of vacuum
hose to replace my boot since, as one respondent noted, it can be
useful to have the dewar vent port available to quickly dump
pressure. If that doesn't work out, I have a fitting that will
do what I want.
Thanks again everyone!
-Steve
Received on Thu Mar 15 2012 - 11:38:07 MST