FLOW-RATE MEASURING APPARATUS

Japanese Patent JP3736139

B2

PROBLEM TO BE SOLVED: To provide a flow-rate measuring apparatus whose measuring accuracy is high and whose measuring range is wide.
SOLUTION: In a flow-rate measuring apparatus, a vortex generating body 2 which generates Karman's vortex to a conductive fluid flowing inside a pipe 1 is provided. In addition, a magnetic-field generating device 3 which is installed in the outer circumference of the pipe 1 on the downstream side of the vortex generating body 2 and by which a generated magnetic field is crossed inside the pipe is provided. In addition, a pair of electrodes 4 which are installed in positions crossed perpendicularly with the magnetic field generated by the magnetic-field generating device 3 and which detect an induced electromotive force due to the change in the magnetic field when the fluid is passed inside the magnetic field are provided. In addition, a computing part 5 which calculates the flow rate of the fluid on the basis of the induced electromotive force is provided, In the flow-rate measuring apparatus, a first flow-rate value is found on the basis of the induced electromotive force of a DC component which is changed in proportion to a flow rate, a second flow-rate value is found on the basis of the frequency of an AC component which is generated to be pulse-shaped by Karman's vortex, the first flow-rate value is used as a measured flow-rate value when the first flow-rate value is outside the detection range of the AC component, and the second flow-rate value is used as a measured flow-rate value when the first flow-rate value is within the detection range of the AC component.

JPH076489	[Name of device] Kalman airflow sensor
WO/2004/074856	FREQUENCY MEASURING METHOD, FREQUENCY MEASURING DEVICE, PHYSICAL QUANTITY MEASURING DEVICE, FLOWMETER, FLOW RATE SENSING SWITCH, METHOD FOR CONTROL FLOWMETER, METHOD FOR CONTROLLING FLOW RATE SENSING SWITCH, AND RECORDED MEDIUM ON WHICH CONTROL PROGRAM IS RECORDED
JPS5830621	FLOWMETER

Hirofumi Nakamura
Sakai Shunsuke

JP27493198A

January 18, 2006

September 29, 1998

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Matsushita Electric Industrial Co., Ltd

G01F1/32; G01F1/00; G01F1/58; G01F7/00; (IPC1-7): G01F1/32

JP5172598A
JP9061206A

Fumio Iwahashi
Hiroki Naito
Daisuke Nagano

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