Electrochemical sensor for measuring the oxygen partial pressure in a process fluid and a method for testing its function

摘要

An electrochemical sensor for measuring the oxygen partial pressure in a process fluid, comprises
an electrolyte-filled sensor body, which is covered on one side charged with the process fluid by an oxygen-permeable membrane,a cathode on the membrane,an annular guard electrode surrounding the cathode, which in measuring operation lies at the same potential as the cathode,an anode charged by the electrolyte in the sensor body,a reference electrode charged by the electrolyte in the sensor body, wherein between the anode and cathode a voltage can be applied, which is controlled between the cathode (8) and reference electrode at a constant polarization voltage and the measuring sensor current flowing in measuring operation between the cathode and anode is a measure for the oxygen partial pressure in the process fluid, anda test voltage source which can be switched in a testing mode between the cathode and guard electrode for producing test oxygen in the electrolyte and/or in the process fluid between the cathode and guard electrode for testing the function of the sensor.

主权项

1. An electrochemical sensor for measuring the oxygen partial pressure in a process fluid, the electrochemical sensor comprising:
an electrolyte-filled sensor body, which is covered on one side charged with the process fluid by an oxygen-permeable membrane; a cathode on the membrane; an annular guard electrode surrounding the cathode, which in measuring operation lies at the same potential as the cathode; an anode charged by the electrolyte in the sensor body; a reference electrode charged by the electrolyte in the sensor body, wherein between the anode and the cathode a voltage can be applied, which can be controlled between the cathode and the reference electrode at a constant polarization voltage, and wherein the measuring sensor current flowing in measuring operation between the cathode and the anode is a measure for the oxygen partial pressure in the process fluid; a test voltage source switching in a testing mode between the cathode and the guard electrode to produce test oxygen in at least one of the electrolyte and the process fluid between the cathode and the guard electrode to test the function of the sensor.