*Fracture of Peltier cooling-water supply Varian 720 AES*
A plea (shown below) went out a couple of weeks ago.
Here is some feedback from a fix we had yeasterday.
The engineer showed me conclusively that the camera had died.
We replaced the camera and everything is now fine - leading to the
question why did the camera fail?
One possibility? On start the instrument is purged of air by argon (our
instrument use is intermittent). The purge last about 15 minutes and the
machine cannot be used in that time.
We had assumed that the machine's interior, including the light path was
being purged. We were wrong. What was being purged was a tiny space in
front of the camera chip.
As we normally don't run wavelengths < 200 nm, we usually ran with
polyboost off. It seems that we were therefore running with a light-path
of air with a Peltier at -35 degrees C.
Have we been using the peltier (and chip) to freeze-dry the light path
and did the chip finally give up as a result?
Why should that coincide with a rupture to the plastic cooling-water
pipe to the Peltier?
So, we don't really know what caused the pipe to break - other than that
is was VERY brittle when removed - and we don't really know why the
Professor of Geochemistry
Director, Cross-faculty ICP Facility
University College London
London WC1E 6BT
Room 111 Kathleen Lonsdale Building
phone +44 (0)20 3108 6362
//Any advice on the following problem would be much appreciated, on- or
//The cooling water for our Varian 720 AES is carried inside the machine
by plastic tubing that runs from the external inlet/outlet to and from
the Peltier in the camera.//
//That tubing became brittle and broke, causing water to release inside
the machine. The tubing has been replaced.//
//The machine appears now to have mis-aligned Ar specra and simply
doesn't work at all.//
//The questions are://
//1. Has anyone experienced breakage of this tubing inside the machine ?//
//2. Have owners of Varian 720s seen this tubing being replaced as part
of an annual service ?//
//3. If answers to either 1 and 2 are yes, were problems experienced
subsequent to tube replacement ?//
//4. Can anyone recommend a service engineer in the UK able to fix this
type of machine ?/