Semiconductor acoustic measurement device that determines the presence or absence of the second ultrasonic measurement

A measurement device comprising:

• a controller which controls an upstream-side first transceiver and a downstream-side second transceiver which transmit/receive an acoustic wave to/from each other in the flow path of a fluid and controls a first measurement including a transmission of a first acoustic wave in one of the first and second transceivers and the reception of the first acoustic wave in the other one of the first and second transceivers and controls a second measurement including a transmission of a second acoustic wave in the other transceiver and the reception of the second acoustic wave in the one transceiver;
• a first detector which detects a first measured value correlated with a propagation time of the first acoustic wave in a first detection period from the transmission to the reception of the first acoustic wave in the first measurement;
• a second detector which detects a second measured value correlated with a propagation time of the second acoustic wave in a second detection period from the transmission to the reception of the second acoustic wave in the second measurement;
• a determiner which determines the presence or absence of the second measurement on the basis of a result of comparison between the first measured value and a previous first measured value measured earlier than the first measured value;
• a first calculator which calculates the propagation time of the first acoustic wave on the basis of the first measured value, and calculates the propagation time of the second acoustic wave on the basis of the second measured value;
• and
• a second calculator which calculates the fluid flow velocity or the flow rate on the basis of the difference between the propagation time of the first acoustic wave and the propagation time of the second acoustic wave when the second measurement is performed, or calculates the flow velocity or the flow rate on the basis of information correlated with the flow velocity or the flow rate of the past when the second measurement is not performed.

A measurement method comprising:

• performing a first measurement including a transmission of a first acoustic wave in one of an upstream-side first position and a downstream-side second position and a reception of the first acoustic wave in the other one of the first and second positions in a flow path of a fluid to detect a first measured value correlated with a propagation time of the first acoustic wave in a first detection period from the transmission to the reception of the first acoustic wave in the first measurement;
• calculating the propagation time of the first acoustic wave on the basis of the first measured value;
• determining the presence or absence of a second measurement including a transmission of the second acoustic wave in the other position and a reception of the second acoustic wave in the one position on the basis of a result of comparison between the first measured value and a previous first measured value measured earlier than the first measured value;
• detecting a second measured value correlated with a propagation time of the second acoustic wave in a second detection period from the transmission to the reception of the second acoustic wave when a decision is made to perform the second measurement;
• calculating the propagation time of the second acoustic wave on the basis of the second measured value when the second measurement is performed;
• and
• calculating the flow velocity or the flow rate of the fluid on the basis of the difference between the propagation time of the first acoustic wave and the propagation time of the second acoustic wave when the second measurement is performed, or calculating the flow velocity or the flow rate on the basis of information correlated with flow velocity or flow rate of the past when the second measurement is not performed.