ULTRASONIC FLOWMETER

• US 20100319464A1
• Filed: 04/26/2007
• Published: 12/23/2010
• Est. Priority Date: 12/27/2006
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Takemura, Koichi, Bessyo, Daisuke, Shiba, Fumikazu
• Granted Patent: US 7,987,731 B2
• Time in Patent Office: Days
• US Class Current: 73/861.28
• CPC Class Codes: G01F 1/667 Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters

Abstract

It is desirable that an operation of an oscillator used for measuring propagation time of ultrasonic waves in an ultrasonic flowmeter be an intermittent operation in order to achieve electric power savings. However, pulse stability of the oscillator requires time, so that there is a problem that the intermittent operation cannot be performed. An ultrasonic flowmeter comprising an oscillator 60, and an oscillation start unit 61 for accelerating oscillation of the oscillator, constructed so that a pulse of the oscillator oscillated by the oscillation start unit 61 is used in measurement of propagation time of ultrasonic waves.

Claims

1. An ultrasonic flowmeter comprising an ultrasonic sensor for sending and receiving ultrasonic waves in a flow path, an oscillator for generating an oscillation of a predetermined frequency, and an oscillation start unit for accelerating stability of the oscillator, wherein a pulse of the oscillator oscillated by the oscillation start unit is used in measurement of propagation time of the ultrasonic waves.

2. An ultrasonic flowmeter as claimed in claim 1, wherein a driving signal is given to the ultrasonic sensor in synchronization with a pulse of the oscillator oscillated by the oscillation start unit and a waiting period is disposed until a driving signal is given to the ultrasonic sensor after being oscillated by the oscillation start unit.

3. An ultrasonic flowmeter as claimed in claim 1, wherein the oscillation start unit comprises another oscillation unit, and a circuit for energizing a pulse of this oscillation unit to the oscillator for a certain period.

4. An ultrasonic flowmeter as claimed in claim 1, wherein a ceramic oscillator is used in the oscillator.

5. An ultrasonic flowmeter as claimed in claim 4, wherein another oscillator B is disposed in addition to an oscillator A used in measurement of propagation time of ultrasonic waves and a pulse cycle of the oscillator A is verified by a pulse of the oscillator B to correct propagation time.

6. An ultrasonic flowmeter as claimed in claim 5, wherein a pulse cycle of the oscillator A is verified continuously following measurement of propagation time.

7. An ultrasonic flowmeter as claimed in claim 2, wherein the waiting time is set at a constant time.

8. An ultrasonic flowmeter as claimed in claim 2, wherein the waiting time is determined based on a result of verifying a pulse cycle of the oscillator.