Sensor unit and sensor module

Abstract

To determine whether an oxygen concentration sensor had reached the end of its lifespan and to obtain accurate measurement results, it was necessary to remove the oxygen concentration sensor from the supply line at predetermined intervals for inspection and calibration. However, such inspection and calibration presents challenges in terms of time and cost. [Solution] The sensor unit 14 includes a main flow path 26 through which gas flows, a venturi tube 28 connected in series with the main flow path 26, a sub-flow path 30 connected to the main flow path 26 and the venturi tube 28, an oxygen concentration sensor 34 provided in the middle of the sub-flow path 30, a first valve 36 provided upstream of the oxygen concentration sensor 34, a second valve 38 provided downstream of the oxygen concentration sensor 34, and outside air ports 42 and 44 for taking in outside air. The first valve 36 and the second valve 38 can switch the connection destination of the oxygen concentration sensor 34 between the main flow path 26 and the outside air ports 42 and 44.