Patent ID: 8815077
Filing Date: 2014-08-26
Classification: G01N

Abstract:
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.