did you checked the needle valve at your inlet?
You closed and reopen it, sometimes the ferrules not tight enough moving
the parts in and out.
What kind of SS tubing you used for this? Could it be, that the surface
in the tube isn´t clean enough?
On 27.06.2011 19:05, Axel Rosas wrote:
> Hello listmembers,
> I have a Delta Adv plus with a Gas Bench II. I've been going back and forth
> with this problem for over a month now and haven't been able to solve it: I
> added about 2mts (6 feet) of 1/8 SS tubing to my He line, also 1/8, because I
> needed to move my gas tanks to a new spot in the lab. So, after making the
> final connection and starting the system back up (turned of filament, closed
> the SGE valve on my Delta, let the whole thing vent for ~15 hrs after opening
> the He flow through the new segment, then backwards..) my Ar signal went
> from 70mV to 780 mV with the same He tank. A simple (?) case of a leak do to
> a faulty connection, you say? Well, thought so to, so I:
> *went back and tightened every connection just a bit...nothing
> *checked the whole line with Snoop, starting at He tank to regulator to SS line
> all the way to the start of the GB...nothing
> **went back and checked the whole He path (SS line and GB) with Argon,
> running a scan of mass 40 on Instrument control panel....nothing
> *I had installed a new regulator, so went back to the old one...nothing.
> *changed the He tank! tried 3 different He tanks, the last one being of better
> grade then the ones I had been using, without a problem, up to this
> *I use two filters: H2O and hydrocarbon. Changed both, one at a
> * eventually went back and connected my He tank through the previous
> point...cant go back!
> * started going backward, towards GB, with the He tank: skipped the SS line
> and connected straight to first filter, then to second filter, then straight to
> GB....still nothing!!
> Argon signal (and 18, 28, 32) has been really crazy. After change in, say, He
> connection spot, it sometimes went down to maybe 130. Thought I had it, let
> the hole thing alone for a day...Ar back up to +700. Signals for water, N and O
> have been behaving much the same way.
> This post has been long enough, so any further info I will be more than glad to
> share off list. Any suggestions will be GREATLY and ETERNALLY appreciated.
> Again, thank you very much and looking forward to your comments....
> Best regards,
Max Planck Institute for Evolutionary Anthropology
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