| 摘要 |
PROBLEM TO BE SOLVED: To improve accuracy in flow rate measurement by correcting with an offset flow rate caused by temperature.SOLUTION: A flow rate measuring device comprises: first and second vibrators 2 and 3 that are provided in a flow channel 1 and transmit and receive ultrasonic signals; time measuring means 10 for measuring propagation time for transmission and reception of an ultrasonic signal; flow rate calculating means 11 for calculating a flow rate from the propagation time measured by the time measuring means 10; an oscillation circuit 21 for generating a reference clock for measuring the propagation time at the time measuring means 10; temperature calculating means 22 for calculating temperature on the basis of a frequency change caused by a temperature change in the oscillation circuit 21; and flow rate correcting means 23 for correcting the flow rate calculated by the flow rate calculating means 11 with an offset flow rate at a desired temperature, the offset flow rate calculated on the basis of the temperature calculated by the temperature calculating means 22. |
