| 摘要 |
PURPOSE: To accurately measure combustible gas component concentration without influence of oxygen concentration by supplying oxygen to gas to be measured under controlled oxygen partial pressure, and burning the component. CONSTITUTION: Gas to be measured containing combustible gas component is passed through a diffusion controlled passage 12 provided in a sensor element 2, and introduced into an inner void space 6 under a predetermined diffusion resistance. In this case, oxygen is pumped by the pumping action of the oxygen generated by applying a predetermined voltage between inner and outer pump electrodes 16 and 18, and the oxygen concentration in the gas to be measured in the space 6 is controlled to a predetermined low concentration value in which the gas component is not burned. The gas to be measured controlled under the oxygen partial pressure is introduced into the space 8 via a diffusion controlled passage 14, the oxygen is supplied by the pumping action of the oxygen by applying a voltage between inner and outer pump electrodes 28 and 30, and the component is burned. At this time, the current flowing to an electrochemical oxygen pump cell formed of the electrodes 28, 30 is measured by a measuring unit 34. Thus, the component concentration can be accurately measured without influence of the oxygen concentration. |
