65
PLC PURIFICATION SYSTEMS |
uSer’S GuiDe
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8. Put back the cleaning disc on the piston. insert it inside the heads holder.
9. Verify that the alignment between the cleaning disc and the heads holder holes is correct.
10. Put back the pump head on the piston by checking that the outlet check valve housing is
on top, and the inlet check valve housing is at the bottom.
11. insert the four fastening screws. tighten slowly in an alternating criss-cross pattern with a
3 mm allen wrench.
12. reconnect the tubing. When tightening the SS nut on the outlet check valve housing, use
a 17 mm spanner to hold the housing and keep the suitable tightening.
Clean or Replace a Pump Check Valve
abnormal pressure fluctuation or the observation of pump noise in the
chromatogram data is usually caused by check valve problems. Dirty or
damaged check valves do not open and close properly, which can cause
pressure fluctuations and irregular flow.
there are four check valves: two per head, one for each inlet, and one for
each outlet.
to clean or replace a check valve, follow the instructions below:
1. Purge the system with a suitable solvent.
2. Switch off the system and disconnect it from
the mains. (refer to
page 33).
3. for an inlet check valve (bottom), disconnect the
etfe inlet tubing by hand (PeeK nut).
4. for an outlet check valve (top), disconnect the SS
outlet tubing with a 3/8” spanner (SS nut). When
loosening the SS nut, use a 17 mm spanner to hold the
housing. you have to remove the tube (i.e., disconnect
it from the purge valve holder).
5. once the tubing is removed, unscrew the check valve
housing using a 17 mm spanner and remove the check
valve. if the check valve is blocked inside the housing,
use a small tool to extract it, in this case, the check
valve must be replaced.
Figure 62
Check Valve
inlet Check Valve,
etfe tubing, and
PeeK nut
outlet
Check
Valve
outlet
Check
Valve
Purge Valve inlets
Figure 63
removing the outlet and inlet tubing
Figure 64
removing the Check Valve Housing and the Check Valve
