Print

Print


Hi Linnea,

Next time I clean the source I'm planning on changing the dual SGE valve
setup (came with our Delta+XL) to a Nupro + Valco 4 way, identical to what
you describe (except that I only plan to use a single Nupro + 4 way, manual
Valco 'under the hood'). My reasoning was identical to yours in that I want
to have a small flow through all capillaries at all times to shorten
switch-over time (mostly because of the huge water background buildup in
the SGE when they are 'shut off').

My questions are:

1) did you drill your own 2 hole ferrules or were you able to find a
supplier? (I've got the Valco 4 way with 1/16" swage ports).

2) did you attach your waste line(s) to a vacuum? I have planned to do so
under the assumption that there won't be any flow unless I pull through the
capillaries. In my case there is an open split between both peripherals and
the Valco (the GC-C III o/s and a Conflo II o/s) so unless there is a
vacuum I'm not sure there will be any flow. If you found this unnecessary,
then maybe I can skip it ...

Cheers,
Steve


At 01:46 PM 12/9/2003 -0800, you wrote:
>Hi Paul,
>
>I have had good luck (touch wood) with Valco 4 port zero volume switching
>valves. To get four peripherals on our system we have two SGE valves (from
>the factory) with a Valco up stream of each SGE. The "EA Valco" switches a
>TC/EA and an EA  (before the Conflo) and the "GC Valco" switches a GasBench
>and a GC-C. I even get a nice leak free connection using the two hole
>composite GC ferrules with the Valco nuts. We mounted the "GC Valco" under
>the hood with about 1 foot of stainless tubing connecting it to the SGE.
>
>The "GC Valvo" configuration:
>port1= waste
>port2= GasBench sample and reference capillaries (2 hole ferrule)
>port3= to SGE #1 (1/16" stainless tubing)
>port4= GCC sample and reference capillaries (2 hole ferrule)
>
>Everyone (the peripherals) seems pretty happy with this set-up and the
>chromatography is not degraded. With gas flowing continuously through
>all  peripheral capillaries in stand-by, the recovery time after switching
>is fairly short. On the "EA Valco" we have a long chunk of capillary at the
>waste port to restrict He flow of the TC/EA in stand-by.
>
>I think the manual Valco runs ~$400. If you want to get super tricky, for a
>bit more cash you could get the electrical actuator and operate switching
>through ISODAT NT.... theoretically.
>
>Don't recall specific part numbers etc., but I would be glad to look them
>up if you are interested. Of course I will probably be busy for the next 3
>months trying to fix a nasty leak at the Valco having now said that it all
>works so well!!
>
>Happy Winter
>Linnea
>
>
>At 09:59 AM 12/9/2003 -0800, you wrote:
>>Bill, and others who might have answers:
>>
>>I am just adding a PreCon to our Delta Plus XL which already has a Gas
>>Bench and Conflo II attached.  The Gas Bench and Conflo II each have a SGE
>>valve, but it will be necessary to unscrew the capillary from the Gas Bench
>>to attach the Precon, and vise versa.  It is immediately apparent that this
>>is going to be tedious and not a good idea in the long term.  Has anyone
>>successfully attached three valves for three continuous flow peripherals to
>>a Delta Plus XL?
>>
>>Thanks in advance,
>>
>>Paul.
>>
>>Paul D. Brooks,
>>Center for Stable Isotope Biogeochemistry,
>>Dept. Integrative Biology MC3140,
>>3060 Valley Life Sciences Building,
>>UC Berkeley, Ca. 94720-3140.
>>
>>[log in to unmask]
>>
>>phone (510)643-1748,
>>FAX (510)643-1749
>>
>>http://ib.berkeley.edu/groups/biogeochemistry/
>
>Linnea Heraty
>Department of Earth and Environmental Sciences
>University of Illinois at Chicago (MC-186)
>845 West Taylor Street
>Chicago, Illinois 60607-7059
>office/lab: 312-413-0098
>fax: 312-413-2279
>email: [log in to unmask]

Stephen W. Taylor
Lab Manager
Isotope Science Laboratory
Dept. of Physics & Astronomy
University of Calgary
2500 University Dr. N.W.
Calgary, Alberta, Canada
T2N-1N4
(t) 403 220 8268
(f) 403 220 7773
[log in to unmask]
www.phas.ucalgary.ca/isl