Zirconia probes are primarily categorized into two types based on the detection method: straight insertion and sampling detection.

Direct Insertion Probe: The direct insertion probe inserts the zirconia probe directly into the measured gas, utilizing the gas's own high temperature to reach the operating temperature of the zirconia without the need for an additional heater. The probe has a simple structure and rapid response, particularly suitable for oxygen concentration measurement in high-temperature environments. For example, in the heating furnaces and boilers of metallurgy, electricity, and other industries, the direct insertion probe is widely used for real-time monitoring of flue gas oxygen content.