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, Em and carrying out the simple calculation shown.}