YOKOGAWA TB820D, User Manual, Page: 65 / 87

<8. MAINTENANCE>
8-4
IM 12B01B30-02EN 2nd Edition : June 09 , 2021-00
8.3 Checking and Replacing Desiccants
Inspect the condition of desiccant once every 6 months and replace it if necessary. Regardless of
the result of the inspection, replace the desiccant once a year.
If the humidity in the detector (the light source unit and the receiver) is high when a sample with
low temperature runs into the Flow cell, condensation may form on the window glass. To prevent
this, the light source unit and the receiver should be kept dry. Remove the desiccants from the
detector unit, and check for softness with the hand. Desiccants that have become soft thoroughly
in gel form should be replaced.
(1) Putting the converter in the maintenance mode.
(2) Loosen the six (6) fixing screws and remove the front cover of the detector unit.
(3) Remove the desiccants and check for softness with the hand. Desiccants soft textured in gel
form should be replaced.
(4) Install the desiccants. The printed side has to be face down. (See Figure 8.3)
(5) Attach the front cover by fastening the six (6) screws.
(6) Put the converter in the measurement mode.
(7) This completes the replacing procedure.
After checking or replacing desiccants, allow the instrument to warm up for at least one hour
before measurement so that desiccants can remove moisture inside the detector.
The desiccants absorb moisture from the side on which letters are printed.
Figure 8.3 Installing the desiccants to the front cover
Arrange the desiccants as below.
Table 8.2 Desiccants
Part No. Name Description
K9657RJ Desiccant 4 pcs/Q’ty
8.4 Pipe Cleaning
Remove the pipes between the detector and the head tank, and clean them.
(1) Putting the converter in the maintenance mode.
(2) Close the sample supply valve.
(3) Close the sample valve and open the drain valve of the head tank to drain the water from
the head tank.
(4) Check that the water in the head tank has been drained off. Remove the pipes between the
detector and the head tank. Clean the inside using a long brush or relevant tool, and wash
away with tap water. If pipes are heavily stained and dirt cannot be removed, replace them
with new ones.
(5) Reinstall the pipes between the detector and the head tank.
(6) Open the sample valve to supply a sample to the head tank. Close the drain valve of the
head tank.
(7) Open the sample supply valve to supply the sample to the detector.
(8) Putting the converter in measurement mode.
(9) Pipe cleaning is now complete.