Yokogawa GC8000 Process Gas Chromatograph - Manual (Page 391)

<6. Maintenance>
6-38
IM 11B08A01-01E
2. When replacing the gland with sample volume of less than 360μl.
3. When gland with engraving is required (Replacement glands do not have the engravings).
 Valve seat for rotary valve
See Figures 6.32 and 6.33.
(1) Stop the operation. (See “3.3.4 Stopping operation” for this procedure).
(2) Turn off the supply of the sample.
(3) If the sample is liquid, purge the sample line with the purge gas (nitrogen gas or instrument
air).
• When the stream switching valve is a pneumatic valve, change the analyzer status to
Manual and turn on the stream switching valve on the sample line to let the purge gas fl ow
in.
• When the stream switching valve is a stop valve, close all the stop valves and open the stop
valve on the sample line to let the purge gas fl ow in.
(4) Close all the stream switching valves.
IMPORTANT
• During the purge, purge gas may fl ow into the sample return line, causing pressure
fl uctuation.
Prepare the sample return line and collection tank, if necessary.
• Prepare the sample return line so that the sample does not return.
(5) 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.
(6) Turn off the supply of the purging air and the carrier gas. For a detection system with an FID,
turn off the supply of hydrogen (or nitrogen) gas and the combustion air as well.
(7) Open the control unit door using a key included in the accessory kit.
(8) Manually loosen the nut and remove the gland assembly.
IMPORTANT
The gland assembly is a vulnerable part. Please handle it with care.
(9) Remove the two screws not coated with red enamel and then remove the rotary valve. Do
not loosen the screws coated with red enamel.
(10) Remove the gasket, gland assembly, and the valve seat, in this sequence. Do not remove
the washer and the coil spring (see Figure 6.32).
(11) As shown in Figure 6.33, the valve seat and gland assembly have a specifi c location to
install. Insert these components in the correct location using the location notch.
(12) Reassemble the components in the reverse order of steps (7) to (9). Firmly tighten the nut
by fi ngers. Do not allow oil or grease to adhere to the seat.
2nd Edition : May 11, 2012-00