Super Systems Gold Probe - Manual (Page 4)

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SSi Gold Probe Manual Rev C
CHARACTERISTICS
The typical zirconia carbon sensor consists of a
closed end tube with the sensing portion at the tip.
The entire tube may be zirconia or there may be a
slug of zirconia cemented in the tip. Fig.1
illustrates the Gold Probe™ design with details
omitted for clarity. The tip of the tube is spring
loaded into contact with the sheath, which also
serves as the outer electrode. The inner electrode
is spring loaded into contact with the inner
zirconia surface. A thermocouple is positioned
close to the inner electrode surface and reference
air bathes the sensing surface.
To the instrument technician, the probe looks like
a battery (see Fig.2.) It displays a voltage, E
c
, from
which the carbon potential can be calculated. The
probe thermocouple is shown next to the sensing
electrode.
The value of the internal resistance can be
measured, as shown in Fig. 3, by putting a shunt
resistor across the probe, measuring the resultant
voltage, E
m
and carrying out the simple calculation
shown.
FIG. 1
FIG. 2
FIG. 3