Yokogawa GC8000 Process Gas Chromatograph - Manual (Page 410)

<6. Maintenance>
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IM 11B08A01-01E
(2) Stop the supply of power.
CAUTION
The isothermal oven is extremely hot after turning off the power immediately. Keep the purging
air supplied for more than an hour after turning off the power. Keep hands away from the oven
components.
(3) Turn off the supply of the purging air. Remove the tubes connected to ports IN, OUT1,
OUT2, and OPEN. When removing the tubes, put labels on them for ease of identifying the
connections later (see Figure 6.49 and Figure 6.50).
(4) Remove the two screws.
(5) Install a new pneumatic valve for actuating the external air supply in the reverse order of
steps (3) and (4).
(6) Confi rming that the piping is correct and there are no leaks.
(7) After completing the piping, follow the steps below.
(a) After fully opening each of the needle valves, rotate it back two turns and lock them.
(b) Feed air and make sure that air comes out from point (1) but not from point (2).
(c) Actuate valve SV11 and make sure that air comes out from (2) but not from (1).
(d) Repeat steps (b) and (c) and confi rm that the reaction times at (1) and (2) do not take more
than 0.5 seconds, with respect to the actuation of SV11.
(e) If the reaction time at (1) was more than 0.5 seconds as a result of step (d), open the EHX1
needle valve by 1/4 turns and check the delay again. If the reexamination still shows the
same result, repeat this step.
(f) If the reaction time at (2) was more than 0.5 seconds as a result of step (d), open the EHX2
needle valves by 1/4 turns and check the delay again. If the reexamination still shows the
same result, repeat this step.
K9193NX
K9193NY
K9193NT
K9193NU
OPE.
EXH1
EXH2
IN
OUT1
OUT2 OUT2
OUT1
IN
EXH2
EXH1
OPE.
K9193NX (K9193NY) K9193NT (K9193NU)
Figure 6.49 Pneumatic Valve for Actuating External Air Supply
2nd Edition : May 11, 2012-00
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