Abstract: The objective of the present invention is to measure gas concentration with a high degree of accuracy. A gas sensor is provided with: a sensor enclosure: an ultrasonic transducer provided at one end of the sensor enclosure; an ultrasonic wave reflecting surface which is provided at the other end of the sensor enclosure and which intersects an axial direction of the sensor enclosure; and a plurality of ventilation holes provided in a side wall of the sensor enclosure. The plurality of ventilation holes are provided at positions such that one side of the sensor enclosure cannot be seen from the other side thereof when viewed from a side surface side of the sensor enclosure, and each ventilation hole has a shape extending in the axial direction of the sensor enclosure.

Abstract: The flow regulating structure comprises a plurality of rail structures. Each rail structure has a plurality of rod-shaped members that are arranged side-by-side with the same direction of extension. The plurality of rail structures are disposed along the direction of gas travel in overlapping positions with space therebetween. The extension directions of the rod-shaped members differ between adjacent rail structures. In each rail structure, the plurality of rod-shaped members are arranged side-by-side with the same direction of extension in both a first virtual plane and a second virtual plane, which face one another in the direction of gas travel, and when viewed from the direction of gas travel, the rod-shaped members disposed on the second virtual plane are positioned between adjacent members among the plurality of rod-shaped members disposed on the first virtual plane.

Abstract: The gas-liquid separator comprises: a swirl structure that causes a gas heading from upstream to downstream to swirl about a flow axis heading from upstream to downstream; a separation structure that discharges outward liquid components contained in the gas passing through the swirl structure; and a deflection structure that is provided downstream of the swirl structure and deflects the gas that has passed through the swirl structure. The deflection structure is provided with: a narrowing core portion that has a three-dimensional shape which narrows from upstream to downstream; and deflecting fins that are provided to the side surface of the narrowing core portion and deflect the gas in the opposite direction to the swirling direction resulting from the swirl structure.

Abstract: The objective of the present invention is to measure gas concentration with a high degree of accuracy. A gas sensor is provided with: a sensor enclosure: an ultrasonic transducer provided at one end of the sensor enclosure; an ultrasonic wave reflecting surface which is provided at the other end of the sensor enclosure and which intersects an axial direction of the sensor enclosure; and a plurality of ventilation holes provided in a side wall of the sensor enclosure. The plurality of ventilation holes are provided at positions such that one side of the sensor enclosure cannot be seen from the other side thereof when viewed from a side surface side of the sensor enclosure, and each ventilation hole has a shape extending in the axial direction of the sensor enclosure.