Patent ID: 6796189
Filing Date: 2004-09-28
Classification: G01F,G01P

Abstract:
A flowmeter, comprising:a flow rate measurement section through which fluid to be measured flows; a pair of ultrasonic wave transducers provided in the flow rate measurement section for transmitting/receiving an ultrasonic wave; a driver circuit for driving one of the ultrasonic wave transducers; a reception detecting circuit connected to the other one of the ultrasonic wave transducers for detecting an ultrasonic wave pulse; a timer for measuring a propagation time based on a receipt detection timing of the ultrasonic wave pulse; a control section for controlling the driver circuit; a calculation section for calculating a flow rate of the fluid to be measured based on an output from the timer; and periodicity change means for sequentially changing a driving method of the driver circuit, wherein the control section controls the periodicity change means such that the frequency of transmission/reception signal in flow rate measurement based on the propagation time of the ultrasonic wave pulse is sequentially changed.