LC Packings SWITCHOS II, User Manual

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The Switching Valves
A-2
D850R3
User’s Manual Switchos II
A.2 Maintenance
In most instances, the only maintenance that is required is cleaning of the valve.
Cleaning can often be accomplished by flushing all the lines with an appropriate
solvent(s). The selection of the solvent is dependent on the nature of the sample
and the mobile phases that are used. Typically solvents such as methanol,
acetonitrile, methanol/water (80/20) or acetonitrile/water (80/20) should be
used.
A.3 Disassembly/Reassembly of the Valve
Note: Do not disassemble the valve unless system malfunction is definitely
isolated to the valve.
A.3.1 Disassembly of the Valve
To disassemble the valve:
a) Use a 9/64” hex driver to remove the socket head screws which secure the
cap to the valve (FIGURE A-1)
Driver
Rotor
Stator
FIGURE A-1. Exploded View of the Valco Model C2 Valve (6-port Version)
b) To insure that the sealing surface of the cap is not damaged, rest it on its
outer face. If the tubing is still attached, leave it suspended by the tubing.
c) Gently pry the rotor away from the driver with your fingers or a small
screwdriver.
d) Examine the rotor sealing surface for scratches.
•
If scratches are visible to the naked eye, the rotor must be replaced.
•
If no scratches are visible, clean all parts thoroughly with an
appropriate solvent. Take care that no surfaces get scratched while
you are cleaning the components.
Note: The most common problem in the use of the valve with HPLC is the
formation of buffer crystals, which are usually water-soluble. After cleaning, it is
not necessary to dry the rotor.