| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic flowmeter capable of stably measuring a flow rate over a long period by preventing mixing of electrical noise into a signal line connecting an ultrasonic transducer with an amplifier circuit. SOLUTION: The ultrasonic flowmeter comprises: a pair of ultrasonic transducer circuits 22 disposed at a predetermined distance from each other on upstream and downstream sides of a passage in which a fluid to be measured flows; a time measuring means for measuring propagation time of ultrasonic signals that are transmitted and received between the pair of ultrasonic transducer circuits 22; and a flow rate measuring means for measuring a flow rate of a fluid to be measured based on propagation time measured by the time measuring means, wherein, each of the pair of ultrasonic transducer circuits 22 includes: an ultrasonic transducer 22a; a signal changeover switch 22b for switching transmission and reception signals transmitted and received between the pair of ultrasonic transducers 22a; and an amplification circuit 22c for amplifying the reception signal by a predetermined gain. COPYRIGHT: (C)2008,JPO&INPIT
|
