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Date: | Thu, 6 Apr 2006 02:44:56 -0500 |
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This sounds familiar. We had a similar experience where the Pirani was not reading accurately (after a power failure and exposure to atmosphere). We determined that the Pirani was the culprit for the disagreement in vacuum readings, but didn't have another one on hand. A quick cleaning of the Pirani remedied the problem. It's surprising what accumulates on the interior-exposed surfaces of a Pirani guage. If you think that might be worth trying, take a look at the Pirani manual and make sure you have the parts necessary to reattach it (rings/gaskets?).
As for the dual inlet results, maybe another reader has a suggestion.
I hope this helps.
-tom
----- Original Message -----
From: Supriya Ghotge <[log in to unmask]>
Date: Wednesday, April 5, 2006 11:36 pm
Subject: [ISOGEOCHEM] Pirani reading showing high
>
> Hi all,
> We have GV Isoprime MS in our lab. Last week we had a power
> failure when the system was kept on pumping overnight.
> Now after starting the system and getting it baked, the analyser
> HV is showing 6e-8mbar and LV is 3e-3mbar, but the pirani reading
> is 3.5e0. Before the powerfailure the pirani was reading 3.0e0-
> 3.2e0.
> We checked all the valves and also the Activated Alumina sieves
> has been changed but no improvement in pirani reading. Background
> scans are also clean with no moisture and any other gases.
> What could be the possible cause for this???
> It would be very helpful if anyone could suggest something on this.
> Regards,
> Supriya.
>
>
>
>
> Supriya G. Karapurkar
> JTA
> IRMS Lab, COD
> National Institute of Oceanography
> Dona Paula, Goa. 403004
> INDIA.
> email: [log in to unmask]
> Tel: +91-0832-2450465
> Fax:+91-0832-2450607
>
> --------------------------------------------
> www.nio.org
> www.indian-ocean.org
> www.reefindia.org
> www.coastalhazards.info
> www.mangroveindia.org
>
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