Replacement Of The Heater Unit - YOKOGAWA ZR22G User Manual

Figure 11.3
(2) Next, make sure that the O-ring groove on the flange surface of the sensor is clean.
Install the metal O-ring in that O-ring groove, and then insert the sensor in the probe while
turning it clockwise. After inserting it until the metal O-ring comes in contact with the probe's
O-ring contact surface, properly align the U-shaped pipe insertion holes with the bolt
openings.
(3) Attach the U-shaped pipe to its support with filter, then fully insert the U-shaped pipe and its
support into the probe.
(4) Coat the threads of the four bolts with anti-seize grease and then screw them in along with
the washers. First, tighten the four bolts uniformly by hand, and then use a torque wrench
to tighten all areas of the metal O-ring uniformly, that is, to make sure the sensor flange is
perfectly horizontal to the O-ring's working face in the probe.
This is done by tightening first one bolt and then its opposing bolt each 1/8 turn, and then
one of the other bolts followed by its opposing bolt, each also 1/8 turn. This continues
in rotating fashion until they are all fully tightened with the torque wrench preset to
approximately 5.9 N • m. If they are not uniformly tightened, the sensor or heater may be
damaged.
Replacement of the sensor assembly is now complete. Install the detector and restart
operation. Calibrate the instrument before making a measurement.
NOTE
Optional Inconel bolts have a high coefficient of expansion. If excess torque is applied while the
bolts are being tightened, abnormal strain or bolt breakage may result.
So, tighten the bolts following the instructions given above.
11.1.4

Replacement of the Heater Unit

This section describes the replacement procedure for the heater unit.
The sensor or ceramic heater-furnace core internal structure is subject to fracturing, so do NOT
subject it to strong vibrations or shock. Additionally, the heater unit reaches high temperatures
and is subjected to high voltages. So, maintenance services should be performed after the power
is off and the heater unit temperature has returned to normal room temperature.
For details, refer to IM11M12A01-21E "Heater Assembly".
NOTE
If the heater strut assembly can not be removed because a screw has fused to its thread, one of
our service representatives can fix it.
Groove in which the contact
(E7042BS) is placed
Installing the Contact
<11. Inspection and Maintenance>
F11.2E.ai
IM 11M12G01-02EN
11-4
1sh Edition : Mar. 25, 2021-00