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Electromagnetic flowmeter

An electromagnetic flowmeter and excitation current technology, which is applied in the application of electromagnetic flowmeters to detect fluid flow, volume/mass flow generated by electromagnetic effects, and measure flow/mass flow. Wave excitation, inability to remove 1/f noise, etc.

Inactive Publication Date: 2004-12-15
YAMATAKE HONEYWELL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, in the rectangular wave excitation method, when the excitation current has a higher frequency, the effects of the impedance of the excitation coil, the response of the excitation current, the response of the magnetic field, and the overcurrent loss of the core of the excitation coil cannot be ignored
Difficult to maintain square wave excitation
As a result, in the rectangular wave excitation method, high-frequency excitation is difficult, and the increase in response to flow velocity changes cannot be achieved nor can 1 / f noise be removed

Method used

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Examples

Experimental program
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no. 1 example

[0168] Next, embodiments of the present invention will be described in detail. Figure 6 is a block diagram showing the structure of the electromagnetic flowmeter according to the first embodiment of the present invention. and figure 1 The same reference numerals in Figure 6 the same components in . The electromagnetic flowmeter according to this embodiment has a measurement pipe 1 , a pair of electrodes 2 a and 2 b , an exciting coil 3 , a power supply unit 4 , a signal conversion unit 5 and a flow rate output unit 6 . The fluid to be measured flows through the measuring pipe 1 . A pair of electrodes 2a and 2b face each other in the measurement pipe 1 so as to be perpendicular to the magnetic field applied to the fluid to be measured and the axis PAX, and are in contact with the fluid to be measured. The electrodes 2a and 2b detect the electromotive force generated by the magnetic field and the flow of the fluid to be measured. A plane PLN comprising the electrodes 2 a...

no. 2 example

[0188] Figure 8 is a block diagram showing the structure of an electromagnetic flowmeter according to a second embodiment of the present invention. and figure 1 and Figure 6 The same reference numerals in Figure 8 the same components in . The electromagnetic flowmeter according to this embodiment has a measuring pipe 1, electrodes 2a and 2b, first and second exciting coils 3a and 3b, a power supply unit 4a, a signal conversion unit 5 and a flow rate output unit 6a. A plane PLN comprising the electrodes 2 a and 2 b and perpendicular to the direction of the measurement conduit axis PAX is defined as the interface in the measurement conduit 1 . In this case, the first and second excitation coils 3 a and 3 b apply an asymmetrical magnetic field to the fluid to be measured on both sides of the plane PLN, ie the interface in the measuring tube 1 . The power supply unit 4a supplies an exciting current having the same frequency and the same phase to the first and second excit...

no. 3 example

[0212] Figure 10 is a block diagram showing the structure of an electromagnetic flowmeter according to a third embodiment of the present invention. and figure 1 , Figure 6 and Figure 8 The same reference numerals in Figure 10 the same components in . In the second embodiment, the offset distance d1 from the plane PLN to the first excitation coil 3a is equal to the offset distance d2 from the plane PLN to the second excitation coil 3b, so that the excitation coils are arranged symmetrically. Instead, as in Figure 10 As shown, the first and second excitation coils 3a and 3b may be arranged according to different offset distances d1 and d2.

[0213] In this embodiment, since the first and second exciting coils 3a and 2b are arranged asymmetrically, an asymmetrical magnetic field can be formed on both sides of the plane PLN in the measuring pipe 1 . Therefore, with the power supply unit 4a, the same exciting current can be supplied to the first and second exciting coi...

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Abstract

When a plane (PLN) which includes electrodes (2a, 2b) and is perpendicular to the direction of an axis (PAX) of a measuring pipe (1) is defined as a boundary in the measuring pipe (1), an exciting coil (3) applies asymmetrical magnetic fields to a fluid to be measured, which flows through the measuring pipe (1), on both sides of the plane (PLN) serving as the boundary in the measuring pipe (1). A signal conversion unit (5) obtains the phase difference between an exciting current supplied to the exciting coil (3) and an interelectrode electromotive force detected by the electrodes (2a, 2b). A flow rate output unit (6) calculates the flow rate of the fluid on the basis of the phase difference obtained by the signal conversion unit (5).

Description

technical field [0001] The invention relates to an electromagnetic flowmeter for measuring the flow velocity of a fluid to be measured flowing through a measuring pipeline, and more particularly, to an excitation method and a signal processing method capable of realizing accurate flow velocity measurement. Background technique [0002] Electromagnetic flowmeters measure the flow velocity of a conductive fluid to be measured flowing through a measurement pipe by converting the flow velocity into an electrical signal using electromagnetic induction. Figure 25 The structure of a conventional electromagnetic flowmeter is shown. This electromagnetic flowmeter has a measuring pipe 11 , a pair of electrodes 12 a and 12 b , an exciting coil 13 , a signal conversion unit 15 and a flow rate output unit 16 . The fluid to be measured flows through the measuring pipe 11 . A pair of electrodes 12a and 12b face each other in the measurement pipe 11, are perpendicular to the magnetic fiel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01F1/58
CPCG01F1/588G01F1/586
Inventor 山本友繁
Owner YAMATAKE HONEYWELL CO LTD