LISTSERV mailing list manager LISTSERV 16.5

Help for ISOGEOCHEM Archives


ISOGEOCHEM Archives

ISOGEOCHEM Archives


ISOGEOCHEM@LIST.UVM.EDU


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

ISOGEOCHEM Home

ISOGEOCHEM Home

ISOGEOCHEM  October 2016

ISOGEOCHEM October 2016

Subject:

Re: AW: [ISOGEOCHEM] GC-TC-irMS leak

From:

gerard olack <[log in to unmask]>

Reply-To:

Stable Isotope Geochemistry <[log in to unmask]>

Date:

Thu, 20 Oct 2016 14:36:45 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (66 lines)

Hi Jeff,

Ar leak check definitely the way to go.  If that does not help, check 
the flow out the bleed out lines.  Those can vary by setup, but are 
typically by the He feed for the backflush and the O2 input.  They 
should have a very low flow, 0.5 mL/min or less with 2 mL/min He flow 
from GC.  No flow could mean a leak upstream or at valve.  High flow 
would mean clog downstream--or leak across valve.

Not sure if this is what is happening in your case, but a couple of hard 
to find problems are:

1. Shaft seal leaks on valve.  You can't always find that using Ar since 
the leak is buried.

2. Capillary pulled out a little bit so it's not all the way thru the 
ferrule.  Instead of tightening around the capillary tube, you end up 
sealing on edge--eventually pushing the capillary out. Re-tightening 
seems to help, but then the leak opens up again. You can end up pinching 
off the flow if you tighten it enough.

When I was playing on GCC, I ended up putting in a union on the line to 
the open split just so I could check flow to the open split.  Depending 
on your exact set up, you may have something similar in place already.  
Just remember to set it up so the mass spec won't be sucking in air when 
play with the plumbing--and open it back up for the Ar leak testing...of 
course if you are picking up a leak via Ar testing with the mass spec 
closed off, you might have other problems ;)

good luck,

gerry



On 10/20/2016 1:02 PM, Dyckmans, Jens wrote:
> Hi Jeff,
>
> I suspect you have a leak between BF valve and open split. This way you basically have no He flow into the open split but air diffusing in. Opening the BF does hardly flush the capillary leading to the open split because the leak is too large. Can you put m/z 40 on the first cup to get a readable value and Ar spray the system downstream of the BF?
>
> Best,
> Jens
>
> Von: Stable Isotope Geochemistry [mailto:[log in to unmask]] Im Auftrag von Jeff Salacup
> Gesendet: Donnerstag, 20. Oktober 2016 19:31
> An: [log in to unmask]
> Betreff: [ISOGEOCHEM] GC-TC-irMS leak
>
> Hi all,
>
> Me again. We've got a large leak somewhere. With the GC split in and the backflush closed we get a slowly increasing Ar signal starting around 400 sec and terminating a minute or so later at a full 50 V. Opening the BF and pulling the GC split out results in a slowly decaying Ar signal that can take an hour to really leave the system.
>
> I initially troubleshot it down to the BF. A flow check at the BF vent suggested it wasn't closing and removing it from the flow path got rid of the problem. So I ordered a new one and installed it. It opens and closes but the problem remains.
>
> I've removed the column from the flow path and the problem remains.
>
> The reactor is new... twice now, just to double check.
>
> The inlet liner ferrule is new.
>
> What am I missing?
>
> Thanks,
>
>

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003
December 2002
November 2002
October 2002
September 2002
August 2002
July 2002
June 2002
May 2002
April 2002
March 2002
February 2002
January 2002
December 2001
November 2001
October 2001
September 2001
August 2001
July 2001
June 2001
May 2001
April 2001
March 2001
February 2001
January 2001
December 2000
November 2000
October 2000
September 2000
August 2000
July 2000
June 2000
May 2000
April 2000
March 2000
February 2000
January 2000
December 1999
November 1999
October 1999
September 1999
August 1999
July 1999
June 1999
May 1999
April 1999
March 1999
February 1999
January 1999
December 1998
November 1998
October 1998
September 1998
August 1998
July 1998
June 1998
May 1998
April 1998
March 1998
February 1998
January 1998
December 1997
November 1997
October 1997
September 1997
August 1997
July 1997
June 1997
May 1997
April 1997
March 1997
February 1997
January 1997
December 1996
November 1996
October 1996
September 1996
August 1996
July 1996
June 1996
May 1996
April 1996
March 1996
February 1996
January 1996
December 1995
November 1995
October 1995
September 1995
August 1995
July 1995
June 1995
May 1995
April 1995

ATOM RSS1 RSS2



LIST.UVM.EDU

CataList Email List Search Powered by the LISTSERV Email List Manager