Varian ProStar 325 UV-Vis, Service Manual

Page: 68 / 149

ProStar325 Service Manual
68
Publication date 8 May 2003
3.22 Back pressure restrictor
The outlet port of the analytical and semi micro flowcells should
be connected to a back pressure restrictor (provided in the ship
kit). Also, the prep 9x1 prep flowcell should also be connected to a
back pressure restrictor when it is used for analytical
measurements.
The back pressure restrictor provides approximately 40psi back
pressure on the flowcell. This prevents outgassing and bubbles
from forming or being trapped in the flowcell, which can cause an
unstable baseline.
Note the arrow stamped on the restrictor body which must point
away from the flowcell outlet port, and toward the waste receiver.
The threaded plastic fittings should be finger tightened only
enough to prevent leaks.
Some 1/16” tubing is supplied at both the inlet and outlet of the
restrictor. The inlet tubing is provided with a 1/16” plastic fitting
for connecting to the flowcell outlet port. Either the outlet tubing
can be directed to the waste container, or the tubing removed,
and the restrictor itself dropped to the bottom of the waste bottle.
The pressure of the restrictor is not adjustable. If it fails or
becomes blocked it will need replacing (p/n 01-107433-00).
4x0.15 Super
Prep 4x0 Micro
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