Penny,

Sometimes the turbo(s) will not vent properly when you shut down the MS.  This leaves low vacuum pressure between the outlet off the turbo and the inlet of the rough pump.  In this condition the rough pump will not start i.e. no gurgling sound.  To fix it all you have to do is open one of the rough pump inlet connections while the rough pump is ON...this will break the vacuum state.

Mark


On Sat, 6 Sep 2008, Penny Higgins wrote:

> I'm having troubles (I think) with our rotary vane pump. I wonder if any of you 
> can help me determine if I really am having a serious problem.
>
> I had to shut down our mass spec for maintenance and I serviced the pump. It's 
> been working fine since. I've had to shut the mass spec down again (for the 
> troubles I described earlier this week) and now when I try to fire up the 
> vacuum pumps, I do not hear the usual gargle from the rough pump - just a 
> clicking that seems to increase over time. I look in the oil window there and 
> rather than seeing the oil flowing like usual, it almost looks like it's 
> splashing and the pump itself is shaking. Before the turbos kicked on, I shut 
> down the whole thing. It's a Pfeiffer Duo 5 (or Duo 5 C - I can't remember) 
> rotary vane pump.
>
> With the troubles I've been having this week, I really don't want to make 
> matters worse with a bad rough pump.
>
> Thanks for your help,
>
> ~Penny
>
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>                      Dr. Pennilyn Higgins
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>  Stable Isotope Ratios in the Environment Analytical Laboratory
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