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Endura AZ25 series probe
Combustion oxygen monitor
3.8 Mounting – Endura AZ25 AutoCal unit
The AutoCal unit can be pipe- or wall-mounted. Refer to Section
3.6.2, page 15 for mounting requirements.
3.9 Mounting – Endura AZ25 probe
The probe can be fitted horizontally or, preferably, vertically for
prolonged high temperature operation.
Mount the probe through the furnace wall using the preferred
method shown in Fig. 3.15. Ensure that a sufficiently large hole
is provided through the mounting (min. bore 42 mm diameter) to
avoid damage to the probe during insertion or use.
In applications such as high temperature incinerators, fluid bed
boilers, and ore roasters, where the level of water vapor in the
waste gases to be measured can be extremely high, it is
important that the mounting flange of the probe, including any
stand-off which may be used, is thermally insulated to minimize
condensation within the probe – see Fig. 3.15.
Condensation within the probe sheath, particularly in outdoor
installations, can be sufficient to allow water to come into
contact with the hot ceramic (zirconia) tube leading to thermal
shock and failure of the sensor. This problem is most likely to
occur on such installations where the plant is shut-down
regularly over the week-end. Additionally, take care to protect
the head of the probe from the elements in out-door
installations.
Raising the temperature of the probe as rapidly as possible will
assist in reducing the level of condensation. This is not possible
on some processes where the plant temperature is gradually
raised to the normal operating level. The temperature rise at the
head of the probe can be assisted by having a large clearance
hole in the refractory allowing hot gases to get up to the
mounting flange/stand-off – see Fig. 3.16.
The problems described above are more likely to occur on
horizontal installations. Where it is not possible to mount the
probe in the vertical position, install the probe with a slope of at
least 10 to 15° downwards from the head of the probe – see
Fig. 3.17.
18
Gasket
Thermal
insulation
Furnace
wall
Min. 42.0 mm dia.
Fig. 3.15 Probe mounting – standard configuration
Thermal
insulation
Fig. 3.16 Probe mounting – for improved probe heating
Furnace
wall
10° min.
Fig. 3.17 Probe mounting – inclined configuration
3 Mechanical installation
Clamp bolt
Fixing flange
Support tube
and flange
(min. bore
42.0 mm dia.)
150 mm (5.91 in.
minimum
Support tube
Furnace wall
Thermal insulation
Support tube
OI/AZ25P–EN Rev. E
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