Title:
ULTRASONIC FLOWMETER
Document Type and Number:
WIPO Patent Application WO/2006/040996
Kind Code:
A1
Abstract:
A propagation time difference type ultrasonic flowmeter using an annular ultrasonic oscillator in which accurate flow rate is determined from a theoretical formula by taking account of the physical properties, e.g. density, of fluid and the dimensions and physical properties of a measuring tube without performing calibration of actual flow. The ultrasonic flowmeter comprises an ultrasonic measuring device for measuring downstream ultrasonic wave propagation time T1, upstream ultrasonic wave propagation time T2 and the period Tp or frequency fp of an ultrasonic wave propagation wave form, and an operating unit performing first operation for calculating a propagation time difference &Dgr T, an average propagation time T0 and a natural angular frequency &ohgr 0 by receiving results of each measurement, second operation for calculating the sound velocity c in the fluid from the distance L between two ultrasonic oscillators, inside diameter a of the measuring tube, damping coefficient R of wall vibration of the measuring tube, density &rgr of fluid to be measured, and the T0 and &ohgr 0, and third operation for calculating the velocity V of fluid from the &Dgr T, T0, L and c.
Inventors:
MATSUSHITA SHIGETADA (JP)
Application Number:
PCT/JP2005/018522
Publication Date:
April 20, 2006
Filing Date:
October 06, 2005
Export Citation:
Assignee:
NIPPON FLOW CELL MFG CO LTD (JP)
MATSUSHITA SHIGETADA (JP)
MATSUSHITA SHIGETADA (JP)
International Classes:
G05F1/66
Foreign References:
| JP2003279396A | 2003-10-02 | |||
| JP2003014514A | 2003-01-15 | |||
| JP2003083787A | 2003-03-19 |
Attorney, Agent or Firm:
Hagiwara, Yasuhiro (Kami-Asao 5-chome Asao-k, Kawasaki-shi Kanagawa 21, JP)
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