| 摘要 |
PROBLEM TO BE SOLVED: To provide a wedge unit used for a Doppler ultrasound flowmeter capable of reducing the sound noise. SOLUTION: The wedge unit used in the Doppler ultrasound flowmeter of this invention comprises a wedge mounted on a part of the outer surface of a piping on one face of the wedge and on its another face an oscillator is mounted, where the oscillator generates the ultrasound by an electric signal, and receives the reflected wave corresponding to the ultrasound, and a spacer to be provided between the wedge and the outer wall of the piping. The thickness ts of the spacer is determined such that the length of the projection of the ultrasound oscillator made by the ultrasound from the ultrasound oscillator on the contact surface between the wedge and the spacer depending on the inclination angle of the other face of the wedge (distance between the point P<SB>1</SB>and the point P<SB>2</SB>, i.e. L') doesn't exceeds the difference L between the incident point (point P<SB>1</SB>) of the ultrasound and the first arrival position (point P<SB>3</SB>) after reflection at the inner surface of the piping. COPYRIGHT: (C)2006,JPO&NCIPI
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