Gas meter for ultrasound measurements in a breathing apparatus having self-draining conduit arrangement

A gas meter for ultrasound measurements in a breathing apparatus, comprising:

• a gas conduit having an inner wall defining an inlet in a first end of the gas conduit and an outlet in a second end of the gas conduit, said inner wall having a lower inner wall surface forming a bottom, relative to a direction of gravity, of an interior of said gas conduit;
• an ultrasound transducer arrangement configured to measure the speed of sound in a gas flowing through a part of said gas conduit forming a measurement chamber;
• said lower inner wall surface of the inner wall being inclined downwardly in said direction of gravity, relative to a horizontal plane in a longitudinal direction of the gas conduit, at both sides of the measurement chamber with a highest part of said lower inner wall surface being situated in said measurement chamber, causing condensation water to be pulled away from the measurement chamber by gravity.