WO2005121716A1 - 電磁流量計 - Google Patents
電磁流量計 Download PDFInfo
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- WO2005121716A1 WO2005121716A1 PCT/JP2005/010684 JP2005010684W WO2005121716A1 WO 2005121716 A1 WO2005121716 A1 WO 2005121716A1 JP 2005010684 W JP2005010684 W JP 2005010684W WO 2005121716 A1 WO2005121716 A1 WO 2005121716A1
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- component
- electromotive force
- angular frequency
- fluid
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/584—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters constructions of electrodes, accessories therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/60—Circuits therefor
Definitions
- the present invention relates to an electromagnetic flowmeter for measuring a flow rate of a fluid to be measured flowing in a measurement pipe, and particularly to a technique of zero correction for automatically correcting a zero point shift.
- a sine-wave excitation type electromagnetic flowmeter that uses a sine wave for the excitation current supplied to the excitation coil has a drawback that it is easily affected by commercial frequency noise, but this drawback is caused by increasing the frequency of the excitation current.
- the problem can be solved by the high frequency excitation method described above.
- a high-frequency excitation type electromagnetic flow meter see, for example, “Japan Metrology Instruments Federation,“ Flow measurement AtoZ for instrumentation engineers ”, Kogyo Gijutsu, 1995, p. 143-160” (Reference 1). )It is described in.
- the high-frequency excitation method has the advantage of being strong against electrochemical noise, spike noise, and lZf noise, and has improved responsiveness (characteristics that the flow signal quickly follows a change in flow rate). There is an advantage that it can be done.
- the magnetic field is constantly changing.
- the measuring tube is separated by the electrode axis.
- the structure is such that the magnetic field is symmetrically distributed before and after.
- the components generated by the time change of the magnetic field are affected by the displacement of the electrodes and the lead wires, the displacement of the symmetry of the magnetic field generated by the coil force, and the like. Therefore, in a sine wave excitation type electromagnetic flow meter, the effect of components generated by the time change of the magnetic field is removed as an offset during calibration, but the effect is affected by the shift of the magnetic field and the change in the distribution of the magnetic field. It is inevitable that the zero point of the flowmeter output will shift.
- the sine wave excitation type electromagnetic flowmeter has a disadvantage that the phase detection does not stabilize the component due to the change in the magnetic field. Was.
- U1 and U3 are periods when the flow velocity of the fluid to be measured is 0, and U2 is a period when the flow velocity is l (mZsec). If the magnitude V of the flow velocity measured by the electromagnetic flow meter changes even though the flow velocity of the fluid to be measured does not change, a shift of 0 point may be considered as a factor of the output fluctuation.
- the output of the electromagnetic flowmeter is 0 (V) when the flow rate of the fluid to be measured is 0 in the initial state, and the output is l (v) when the flow rate is l (mZsec).
- the output of the electromagnetic flow meter is a voltage representing the magnitude V of the flow velocity.
- the conventional sine-wave excitation type electromagnetic flowmeter cannot ensure the stability of the zero point of the output, and the rectangular wave excitation type electromagnetic flowmeter also has a high frequency excitation. There was a problem that the stability of 0 point could not be secured. In addition, even if there is a difference between the sine wave excitation method and the square wave excitation method, the error of the output 0 point cannot be corrected while the fluid to be measured is flowing. there were.
- the present invention has been made to solve the above-described problem, and has as its first object to provide an electromagnetic flowmeter capable of ensuring the stability of the output zero point even in high-frequency excitation. I do.
- a second object of the present invention is to provide an electromagnetic flowmeter that can correct an error at a zero point of the output without reducing the flow rate of the fluid to be measured to zero.
- An electromagnetic flowmeter includes a measurement tube through which a fluid to be measured flows, an excitation unit that applies a time-varying magnetic field to the fluid, and a magnetic field that is provided in the measurement tube and is applied to the fluid.
- the electromotive force of the 3 AZ 3 component (A is a vector potential, t is time) unrelated to the flow velocity of the fluid and the v XB component (V is the flow velocity , B is an electrode for detecting a combined electromotive force with the electromotive force of magnetic flux density), a signal converter for extracting the 3AZ3t component from the combined electromotive force, and Only the vXB component is extracted by removing the extracted dA / dt component, and the vXB component force also includes a flow rate output unit that calculates the flow rate of the fluid.
- FIG. 1A is a diagram for explaining a basic principle of the electromagnetic flow meter of the present invention, and is a diagram showing a vector of a 3 A / dt component and a vector of a vXB component.
- FIG. 1B is a diagram for explaining the basic principle of the electromagnetic flow meter of the present invention, and shows a vector of a vX B component obtained when a vector of a d A / dt component is subtracted from a composite vector.
- FIG. 1B is a diagram for explaining the basic principle of the electromagnetic flow meter of the present invention, and shows a vector of a vX B component obtained when a vector of a d A / dt component is subtracted from a composite vector.
- FIG. 2 is a block diagram for explaining the principle of the electromagnetic flow meter according to the first embodiment of the present invention.
- FIG. 3 is a diagram showing an eddy current and an interelectrode electromotive force when the flow rate of a fluid to be measured is 0 in the electromagnetic flow meter according to the first embodiment of the present invention.
- FIG. 4 is a diagram showing an eddy current and an electromotive force between electrodes when the flow rate of the fluid to be measured is not 0 in the electromagnetic flow meter according to the first embodiment of the present invention.
- FIG. 5A is a diagram showing the inter-electrode electromotive force in a complex vector in the first embodiment of the present invention.
- FIG. 5B is a diagram in which the electromotive force difference and the vXB component are represented by complex vectors in the first embodiment of the present invention.
- FIG. 6 is a block diagram showing a configuration of an electromagnetic flow meter according to a first embodiment of the present invention.
- FIG. 7 is a flowchart showing operations of a signal conversion unit and a flow rate output unit according to the first embodiment of the present invention.
- FIG. 8A is a diagram in which an interelectrode electromotive force is represented by a complex vector in a second embodiment of the present invention.
- FIG. 8B is a diagram in which the electromotive force difference and the vXB component are represented by complex vectors in the second embodiment of the present invention.
- FIG. 9 is a flowchart showing operations of a signal conversion unit and a flow rate output unit according to a second embodiment of the present invention.
- FIG. 10A is a diagram in which an interelectrode electromotive force is represented by a complex vector in a third embodiment of the present invention.
- FIG. 10B is a diagram showing the complex electromotive force difference and vXB component in the third embodiment of the present invention.
- FIG. 10B is a diagram showing the complex electromotive force difference and vXB component in the third embodiment of the present invention.
- FIG. 11 is a flowchart showing operations of a signal conversion unit and a flow rate output unit according to a third embodiment of the present invention.
- FIG. 12A is a diagram in which an interelectrode electromotive force is represented by a complex vector in a fourth embodiment of the present invention.
- FIG. 12B is a diagram in which a sum of electromotive force, an electromotive force difference, and a vXB component are represented by complex vectors in a fourth embodiment of the present invention.
- FIG. 13 is a flowchart showing operations of a signal conversion unit and a flow rate output unit according to a fourth embodiment of the present invention.
- FIG. 14A is a diagram in which an interelectrode electromotive force is represented by a complex vector in a fifth embodiment of the present invention.
- FIG. 14B is a diagram in which the electromotive force difference and the vXB component are represented by complex solid representation in the fifth embodiment of the present invention.
- FIG. 15A is a diagram in which an interelectrode electromotive force is represented by a complex vector in a sixth embodiment of the present invention.
- FIG. 15B is a diagram in which a sum of electromotive force, an electromotive force difference, and a vXB component are represented by complex vectors in a sixth embodiment of the present invention.
- FIG. 16 is a cross-sectional view showing one example of an electrode used in the electromagnetic flow meter of the present invention.
- FIG. 17 is a cross-sectional view showing another example of an electrode used in the electromagnetic flow meter of the present invention.
- FIG. 18 is a diagram for explaining a zero-point shift in the electromagnetic flowmeter.
- a cosine wave P'cos (co, t) and a sine wave Q'sin (co, t) of the same frequency and different amplitudes are combined into the following cosine wave.
- P and Q are amplitudes and ⁇ is an angular frequency.
- Equation (2) is a notation for a complex vector, and j is an imaginary unit.
- L gives the length of the complex vector, and ⁇ gives the direction of the complex vector. Therefore, in order to analyze the geometric relationship on the complex coordinate plane, it is convenient to utilize the conversion to a complex vector.
- the vector Va is a magnetic field. Is a vector that depends only on the time change of the measured fluid and is independent of the magnitude V of the measured fluid velocity, and the vector Vb is a vector whose magnitude changes in proportion to the magnitude V of the measured fluid velocity. Pay attention to the fact that it is nod.
- the vector Va of the dA / dt component is calculated from the composite vector Va + Vb.
- the guess value Va 'and subtracting this guess value Va is extracted, and based on this vX B component, the flow velocity of the fluid to be measured is calculated.
- the size V is calculated. It is important to be able to extract only the vector Vb without setting the vector Vb to 0 (without setting the flow rate to 0) and without setting the vector Va to 0 (without setting the excitation frequency to 0).
- FIGS. 1A and IB the basic principle of the present invention for actually correcting the zero point of the output of the electromagnetic flowmeter will be described with reference to FIGS. 1A and IB.
- Re is the real axis and Im is the imaginary axis.
- OutO is the output before the zero correction when the flow velocity is 0
- outV is the output before the zero correction when the flow velocity is V.
- the vector mapped on the complex plane is calculated as the combined vector Va + Vb of the following dA / dt component vector Va and vXB component vector Vb: Equivalent to.
- Vb rvexp (j- ⁇ v) -V... (4)
- FIG. 1A shows the vectors Va and Vb.
- the vector Va of the dA / dt component is an electromotive force generated by a change in the magnetic field, and therefore has a magnitude proportional to the excitation angular frequency ⁇ .
- the known proportionality constant portion 3 ⁇ 4 ⁇ with respect to the magnitude of the vector Va is assumed, and the direction of the vector Va is assumed to be 0 ⁇ .
- the vector Vb of the vX B component is an electromotive force generated by the movement of the fluid to be measured in the measurement tube, and therefore has a magnitude proportional to the magnitude V of the flow velocity.
- rv be the known proportionality constant with respect to the magnitude of the vector Vb
- ⁇ V be the direction of the vector.
- the factor at which the output of the electromagnetic flowmeter fluctuates at the zero point is a fluctuation of the 3AZ3t component. Therefore, if the estimated value Va 'of the vector Va of the dA / dt component is extracted, and the magnitude V of the flow velocity is obtained by a signal conversion equation in which the estimated value Va' of the vector Va is removed from the combined vector Va + Vb, Thus, automatic correction of zero points can be realized.
- the excitation frequency is switched to a binary value, and the estimated value Va of the 3AZ3t component vector Va is calculated from the difference between the electromotive forces between the electrodes in two excitation states having different excitation frequencies. It is a method of extracting.
- the complex vector that can be obtained directly from the interelectrode electromotive force is the composite vector Va + Vb, and the vectors Va and Vb cannot be directly measured. Yes. Therefore, the magnitude of the vector Va of the 3AZ3t component is proportional to the excitation frequency ⁇ , and attention is paid to the fact that the vector Vb of the ⁇ component does not depend on the excitation frequency ⁇ .
- the difference between the combined vector Va + Vb when excited at a certain angular frequency ⁇ and the combined vector Va + Vb when excited at another angular frequency ⁇ 1 is determined. Since this difference is a vector that gives only a change in the magnitude of the vector Va of the 3AZ3t component, an estimated value Va ′ of the change component vector Va can be extracted.
- a second extraction method applies a magnetic field at a plurality of excitation frequencies to a fluid to be measured, and uses the frequency difference between a plurality of components included in the interelectrode electromotive force to calculate the 3AZ3t component vector Va.
- This is a method of extracting the guess value Va '.
- the point of interest is the same as in the first extraction method. Specifically, a magnetic field including two components having the same magnitude of the exciting coil force and different frequencies is applied to the fluid to be measured, and the combined vector Va + Vb of the first frequency component and the combined vector Va + Vb of the second frequency component are applied. Find the difference from Va + Vb.
- this difference is a vector that gives only a change in the magnitude of the vector Va of the 3AZ3t component, an estimated value Va ′ of this change component vector Va can be extracted.
- the second extraction method unlike the first extraction method, it is not necessary to switch the excitation frequency, so that zero correction can be performed at high speed.
- the vector Vb of the vXB component can be extracted.
- This vector Vb force can also calculate the magnitude V of the flow velocity of the fluid to be measured as follows.
- the magnitude V of the flow velocity of the fluid to be measured can be measured irrespective of the fluctuation of the dA / dt component induced by the time-varying magnetic field. Will be realized.
- FIG. 2 is a block diagram for explaining the principle of the electromagnetic flow meter of the present embodiment.
- the electromagnetic flowmeter is configured so that the measurement pipe 1 is perpendicular to both the measurement pipe 1 through which the fluid to be measured flows and the axis PAX of the measurement pipe 1 and the magnetic field applied to the measurement fluid and is in contact with the measurement fluid. And a pair of electrodes 2a and 2b for detecting an electromotive force generated by the magnetic field and the flow of the fluid to be measured, and a plane PLN including the electrodes 2a and 2b orthogonal to the direction of the measurement tube axis PAX. An excitation coil 3 for applying a time-varying magnetic field to the fluid to be measured, which is asymmetrical before and after the measuring tube 1 with the plane PLN as the boundary, when the boundary is the constant tube 1.
- a magnetic field component (magnetic flux) orthogonal to both the electrode axis EAX and the measurement tube axis PAX on the electrode axis EAX connecting the electrodes 2 a and 2 b Density) B1 is given as follows.
- Equation (6) bl is the amplitude of the magnetic field B1
- ⁇ is the angular frequency
- 01 is the phase difference (phase delay) from co O't.
- the magnetic flux density B1 is referred to as a magnetic field B1.
- the interelectrode electromotive force that is caused by a change in the magnetic field and is independent of the flow rate of the fluid to be measured will be described. Since the electromotive force due to the change in the magnetic field depends on the time derivative of the magnetic field, dBlZdt, the magnetic field B1 generated from the exciting coil 3 is differentiated as in the following equation.
- the generated eddy current is only a component caused by a change in the magnetic field, and the eddy current I due to the change in the magnetic field Ba has a direction as shown in FIG. Therefore, in the plane including the electrode axis EAX and the measurement tube axis PAX, the interelectrode electromotive force E generated by the change of the magnetic field Ba and independent of the flow velocity has the direction shown in FIG. This direction is the minus direction.
- the interelectrode electromotive force E is obtained by multiplying the time derivative dB lZdt of the magnetic field considering the direction by the proportional coefficient rk and replacing the phase 0 1 with 0 1 + 0 00 as shown in the following equation.
- Rk, ⁇ 100 relates to the conductivity and permittivity of the fluid to be measured and the structure of the measuring tube 1 including the arrangement of the electrodes 2a, 2b).
- the interelectrode electromotive force Ec of the equation (12) converted into complex coordinates is caused only by the time change of the magnetic field, and becomes an interelectrode electromotive force independent of the flow velocity.
- Rk'coO'bl'exp ⁇ j 'Z2 + 01+ 000) ⁇ in equation (12) is a complex vector whose length is rk'coO'bl and whose angle from the real axis is ⁇ 2 + ⁇ 1 + 000. .
- proportional coefficient rk and angle ⁇ ⁇ 00 can be represented by the following complex vector kc.
- the interelectrode electromotive force caused by the flow velocity of the fluid to be measured will be described.
- the magnitude of the flow velocity of the fluid to be measured is V (V ⁇ 0)
- the generated eddy current includes the component vXBa due to the velocity vector V of the fluid to be measured, in addition to the eddy current I when the flow velocity is 0.
- the eddy current Iv due to the velocity vector V and the magnetic field Ba is oriented as shown in Fig. 4.
- the interelectrode electromotive force Ev generated by the flow velocity vector V and the magnetic field Ba is opposite to the interelectrode electromotive force ⁇ ⁇ ⁇ ⁇ generated by the time change, and the direction of ⁇ is the plus direction.
- the interelectrode electromotive force Ev resulting from the flow velocity is obtained by multiplying the magnetic field B1 by the proportional coefficient rkv and replacing the phase 01 with 01 + 001 as shown in the following equation (rkv, ⁇ 01 Is related to the magnitude V of the flow velocity, the conductivity and permittivity of the fluid to be measured, and the structure of the measuring tube 1 including the arrangement of the electrodes 2a and 2b).
- equation (15) when equation (15) is mapped on a complex coordinate plane with reference to coO′t, the real axis component Evx and the imaginary axis component Evy are as follows.
- Kvc Kvx + jEvy
- the interelectrode electromotive force Eve of the equation (18) converted to complex coordinates is caused by the flow velocity of the fluid to be measured. Between the electrodes.
- Rkvbl'exp ⁇ j '(01 + 001) ⁇ in equation (18) is a complex vector having a length of rk'b1 and an angle from the real axis of 01 + 001.
- the above-mentioned proportionality coefficient rkv and angle ⁇ 01 can be represented by the following complex vector kvc.
- rkv is the magnitude of the vector kvc
- ⁇ 01 is the angle of the vector kvc with respect to the real axis.
- rkv corresponds to the proportional coefficient rk (see equation (13)) multiplied by the flow velocity magnitude V and the proportional coefficient ⁇ . That is, the following equation is established.
- the total interelectrode electromotive force Eac which is the sum of the interelectrode electromotive force Ec caused by the time change of the magnetic field and the interelectrode electromotive force Eve caused by the flow velocity of the fluid, is expressed by the following equation (18).
- Expression (12) By adding the substituted expression and Expression (12), it is expressed by the following expression.
- the interelectrode electromotive force Eac is represented by rk * coO'bl ⁇ ⁇ ⁇ ] ( ⁇ / 2 + ⁇ 1 + 000) ⁇ which is a 3AZ3t component. It is described by two complex vectors of ⁇ -rk-V-bl-expij- ⁇ 1 + ⁇ 01) ⁇ which is the ⁇ component.
- the length of the combined vector obtained by combining the two complex vectors represents the amplitude of the output (electromotive force Eac), and the angle ⁇ of the combined vector is the electrode with respect to the input (excitation current) phase coO't. Indicates the phase difference (phase delay) of the inter-electromotive force Eac.
- the power Eac is E10
- a state in which the excitation angular frequency is changed from ⁇ to ⁇ 1 in the first excitation state is referred to as a second excitation state
- the interelectrode electromotive force Eac in the second excitation state is E11.
- the inter-electromotive force El 1 is given by the following equation from equation (22).
- Fig. 5 ⁇ shows a complex vector representation of the interelectrode EMF, ElO, . E10 3 AZ3t in Fig.
- 5A represents the 3 AZ3t component rk'bl'exp ⁇ j '( ⁇ 1 + ⁇ 00) ⁇ ⁇ ⁇ ⁇ ⁇ (] t represents the 3 ⁇ 3t component of the electromotive force Ell between electrodes rk'bl-exp ⁇ j- ( ⁇ 1 + ⁇ 00) ⁇ ⁇ ⁇ 1 -exp j- ⁇ / 2), and ElOEllvXB represents the electromotive force E10, Represents the vXB component of Ell.
- EdAl (E10-Ell) ⁇ 0 / ( ⁇ 0- ⁇ 1)
- the electromotive force difference EdAl shown in equation (24) is not related to the magnitude V of the flow velocity. Therefore, only the components generated are generated.
- the interelectrode electromotive force E10 synthetic vector Va + Vb
- the electromotive force difference EdAl is exactly the electromotive force difference between the interelectrode electromotive forces E10 and Ell multiplied by ⁇ OZ ( ⁇ O ⁇ l), but is multiplied by ⁇ 0 / ( ⁇ - ⁇ 1). The reason is to facilitate the expansion of the expression.
- VXB component obtained when the electromotive force difference EdAl shown in Expression (24) is subtracted from the interelectrode electromotive force E10 shown in Expression (22) is EvBl
- the VXB component EvBl is expressed by the following expression.
- the ⁇ component EvBl is not related to the angular frequency ⁇ .
- the ⁇ ⁇ component EvBl also becomes 0.
- the output with the 0 point corrected can be obtained from the vXB component EvBl so that the force component can be obtained.
- Figure 5B shows a complex vector representation of the above electromotive force difference EdAl and vXB component EvBl. According to equation (25), the magnitude and direction of the coefficient relating to the magnitude V of the flow velocity are represented by the complex vector [0 ⁇ ⁇ ⁇ 1) 1 ⁇ ⁇ ⁇ ; ⁇ ⁇ ( ⁇ 1+ ⁇ + ⁇ ⁇ 01) ⁇ ].
- V I ⁇ 1 / [ ⁇ -rk-bl-expij- ( ⁇ 1+ ⁇ 00+ ⁇ ⁇ 01) ⁇ ]
- FIG. 6 is a block diagram showing the configuration of the electromagnetic flow meter of the present embodiment, and the same components as those in FIG. 2 are denoted by the same reference numerals.
- the electromagnetic flowmeter of the present embodiment includes a measuring pipe 1, electrodes 2a and 2b, and electrodes 2a and 2b.A plane perpendicular to the direction of the measuring pipe axis PAX PLN force A position separated by an offset distance d in the axial direction. , A power supply unit 4 for supplying an exciting current to the exciting coil 3, and a combined electromotive force detected by the electrodes 2a and 2b in each of the first exciting state and the second exciting state.
- the difference between the combined electromotive force in the first excitation state and the combined electromotive force in the second excitation state is extracted as the d AZ dt component based on the amplitude and phase of the combined electromotive force.
- Only the vXB component is extracted by removing the 3AZ3t component from the combined electromotive force in the signal converter 5 and the combined excitation power in one of the first and second excitation states.
- the vXB component force also has a flow rate output unit 6 for calculating the flow rate of the fluid.
- the excitation coil 3 and the power supply unit 4 serve as an excitation unit that applies a time-varying magnetic field to the fluid to be measured.
- the power supply unit 4 sets a first excitation state in which an excitation current having an angular frequency ⁇ is supplied to the excitation coil 3.
- FIG. 7 is a flowchart showing the operation of the signal conversion unit 5 and the flow output unit 6.
- the signal converter 5 determines the amplitude rlO of the electromotive force E10 between the electrodes 2a and 2b in the first excitation state where the excitation angular frequency is ⁇ , and determines the phase difference between the real axis and the interelectrode electromotive force E10.
- ⁇ 10 is determined by a phase detector (not shown) (step 101 in FIG. 7).
- the signal conversion unit 5 determines the amplitude rll of the electromotive force E11 between the electrodes 2a and 2b, and determines the relationship between the real axis and the interelectrode electromotive force E11.
- the phase difference ⁇ 11 is obtained by a phase detector (step 102).
- the signal conversion unit 5 calculates the real axis component ElOx and the imaginary axis component E10y of the interelectrode electromotive force E10 and the real axis component Ellx and the imaginary axis component Elly of the interelectrode electromotive force El1 as follows. It is calculated as in the equation (step 103).
- the signal conversion unit 5 calculates the magnitude of the electromotive force EdAl between the interelectrode electromotive forces E10 and E11 (step 104).
- the process of step 104 is a process corresponding to obtaining the 3AZ3t component, and is a process corresponding to the calculation of equation (24).
- the signal conversion unit 5 calculates the real axis component EdAlx and the imaginary axis component EdAly of the electromotive force difference EdAl as in the following equation.
- EdAlx (ElOx-Ellx) ⁇ ⁇ / ( ⁇ - ⁇ 1)... (31)
- step 105 the flow output unit 6 removes the electromotive force difference EdAl from the interelectrode electromotive force E10, and obtains the magnitude of the vXB component EvBl (step 105).
- the process of step 105 is a process corresponding to the calculation of equation (25).
- the flow output unit 6 calculates the magnitude I EvBl
- Step 106 calculates the magnitude V of the flow velocity of the fluid to be measured as in the following equation (Step 106).
- the process of step 106 is a process corresponding to the calculation of equation (26).
- V I EvBl I / rv (34)
- the proportional coefficient rv is a constant that can be obtained in advance by calibration or the like.
- the signal conversion unit 5 and the flow rate output unit 6 perform the processing of steps 101 to 106 as described above at regular intervals until, for example, the measurement end is instructed by the operator (YES in step 107).
- the electromotive force difference EdAl (d A / dt component vector Va) is extracted from the interelectrode electromotive forces E10 and E11 in two excitation states having different excitation frequencies.
- the VXB component was extracted, and the VXB component force was calculated as the flow rate of the fluid to be measured.
- the zero point of the output of the electromagnetic flowmeter can be corrected without setting the flow rate of the fluid to be measured to zero, and the stability of the zero point can be ensured even in the high-frequency excitation.
- the 3 AZ 3t component is removed from the interelectrode electromotive force E10 in the first excitation state to extract the v XB component, but the second excitation state
- the 3 AZ 3 t component may be removed from the interelectrode electromotive force El 1 to extract the VXB component.
- This embodiment uses the second extraction method as a method for extracting the estimated value Va ′ of the vector 3AZ3t component Va among the methods described in the basic principle, and uses a magnetic field with a plurality of excitation frequencies. Is applied to the fluid to be measured, and the estimated value Va of the 3AZ3t component vector Va is extracted using the difference between the multiple frequency components included in the interelectrode electromotive force. Since the configuration of the electromagnetic flow meter of the present embodiment is the same as that of the electromagnetic flow meter of the first embodiment shown in FIG. 6, the principle of the present embodiment will be described using the reference numerals in FIG.
- Equation (35) ⁇ , ⁇ are different angular frequencies
- b2 is the amplitude of the component of angular frequency ⁇ of the magnetic flux density ⁇ 2 and the amplitude of the component of angular frequency ⁇
- ⁇ 2 is the difference between the component of angular frequency ⁇ and ⁇ ⁇ t.
- the total sum of the electromotive force obtained by converting the interelectrode electromotive force resulting from the time change of the magnetic field into a complex vector and the electromotive force obtained by converting the interelectrode electromotive force resulting from the flow velocity of the fluid into a complex vector is obtained. If the EMF of the component of angular frequency ⁇ is E20c among the EMFs between the electrodes, the EMF between the electrodes is expressed by the following equation similar to the equation (21).
- the entire electrode obtained by combining the electromotive force obtained by converting the interelectrode electromotive force resulting from the time change of the magnetic field into a complex vector and the electromotive force obtained by converting the interelectrode electromotive force resulting from the fluid flow velocity into a complex vector is combined.
- the electromotive force of the component of angular frequency ⁇ 1 among the inter-electromotive forces is E21c
- the interelectrode electromotive force E21c is expressed by the following equation similar to equation (21).
- E21 is represented by the following equation.
- FIG. 8A shows a diagram in which the interelectrode electromotive forces # 20 and E21 are represented by complex vectors.
- ⁇ 2 03 AZ3t in Fig. 8 ⁇ represents the 3 AZ3t component rk'b2'exp ⁇ j '( ⁇ 2+ ⁇ 0 0) ⁇ ⁇ ⁇ 0' exp (j ⁇ ⁇ / 2) at the interelectrode electromotive force ⁇ 20.
- EdA2 (E20-E21) ⁇ ⁇ / ( ⁇ — ⁇ 1)
- the electromotive force difference EdA2 shown in the equation (40) is not related to the magnitude V of the flow velocity! Therefore, it is only a component generated by 3AZ3t.
- the interelectrode electromotive force E20 (composite vector Va + Vb) force vXB component is extracted using the electromotive force difference EdA2.
- the electromotive force difference EdA2 is exactly ⁇ 0Z ( ⁇ 0 ⁇ 1) times the electromotive force difference between the interelectrode electromotive forces E20 and E21, but is multiplied by ⁇ 0 / ( ⁇ 0 ⁇ 1). The reason is to facilitate the expansion of the expression.
- VXB component EvB2 is expressed by the following expression.
- EvB2 E20-EdA2
- the vXB component ⁇ 2 is not related to the angular frequencies ⁇ , ⁇ 1.
- the magnitude of the flow velocity V When the force is 0, the ⁇ ⁇ component ⁇ 2 also becomes 0
- the 0 point has been corrected from the vXB component EvB2 so that the force also contributes You can get the output.
- Figure 8B shows a complex solid representation of the above electromotive force difference EdA2 and vXB component EvB2. According to equation (41), the magnitude and direction of the coefficient relating to the magnitude V of the flow velocity are represented by a complex vector [ ⁇ ⁇ ⁇ ⁇ 1) 2 ⁇ ⁇ ⁇ ; ⁇ ⁇ (02 + 0 ⁇ + ⁇ 01) ⁇ . expressed.
- V I ⁇ 2 / [ ⁇ -rk-b2-exp ⁇ j- ( ⁇ 2+ ⁇ 00+ ⁇ ⁇ 01) ⁇ ]
- Table 2 below shows the correspondence between the constants and variables used in the basic principle and the constants and variables in this embodiment. As is clear from Table 2, this embodiment is one example that specifically realizes the basic principle.
- the electromagnetic flow meter according to the present embodiment has a measurement tube 1, electrodes 2a and 2b, an exciting coil 3, a power supply unit 4, and a first frequency ⁇ of the combined electromotive force detected by the electrodes 2a and 2b.
- a signal converter 5 for determining the amplitude and phase of the two frequency components of the wave number ⁇ 1, and extracting the electromotive force difference between the two frequency components as a 3 ⁇ 3 t component based on the amplitude and phase;
- a flow output unit 6 for extracting only the ⁇ ⁇ ⁇ component by removing the 3 ⁇ 3 t component from the components of the frequency ⁇ ⁇ and calculating the flow rate of the ⁇ ⁇ ⁇ component force fluid.
- the power supply unit 4 supplies an exciting current including a sine wave component of the first angular frequency ⁇ and a sine wave component of the second angular frequency ⁇ 1 to the exciting coil 3. At this time, the component of the angular frequency ⁇ and the component of the angular frequency ⁇ 1 in the exciting current have the same amplitude.
- FIG. 9 is a flowchart showing the operation of the signal conversion unit 5 and the flow rate output unit 6.
- the signal converter 5 determines the amplitude r20 of the electromotive force ⁇ 20 of the component of the angular frequency ⁇ 0 of the electromotive force between the electrodes 2a and 2b, and also calculates the phase difference ⁇ 20 between the real axis and the interelectrode electromotive force E20. Is obtained by a phase detector (not shown).
- the signal converter 5 calculates the amplitude r21 of the electromotive force E21 of the component of the angular frequency ⁇ 1 of the electromotive force between the electrodes 2a and 2b, and calculates the phase difference ⁇ 21 between the real axis and the interelectrode electromotive force E21. Determined by a phase detector (Step 201 in Fig. 9).
- the interelectrode electromotive force E20, E21 is a force that can be frequency-separated by a band-pass filter.In fact, if a comb-shaped digital filter called a comb filter is used, the two angular frequencies ⁇ , ⁇ ⁇ Can be easily separated into minutes.
- the signal converter 5 calculates the real axis component ⁇ 20 ⁇ of the interelectrode electromotive force ⁇ 20 ⁇ and the imaginary axis component E20y, and the real axis component E21x and the imaginary axis component E21y of the interelectrode electromotive force E21 as follows: (Step 202).
- the signal converter 5 calculates the magnitude of the electromotive force difference EdA2 between the interelectrode electromotive forces E20 and E21 (Step 203).
- the process of step 203 is a process corresponding to obtaining the dA / dt component, and is a process corresponding to the calculation of equation (40).
- the signal converter 5 calculates the real axis component EdA2x and the imaginary axis component EdA2y of the electromotive force difference EdA2 as follows: Is calculated.
- EdA2x (E20x-E21x) ⁇ ⁇ OZ ( ⁇ 0— ⁇ 1) ⁇ ⁇ ⁇ (47)
- EdA2y (E20y-E21y) ⁇ ⁇ OZ ( ⁇ 0— ⁇ 1) ⁇ ⁇ ⁇ (48)
- the flow output unit 6 removes the electromotive force difference EdA2 from the interelectrode electromotive force ⁇ 20, and obtains the magnitude of the vXB component EvB2 (step 204).
- the process of step 204 is a process corresponding to the calculation of equation (41).
- the flow output unit 6 calculates the magnitude I EvB2
- step 205 the flow rate output unit 6 sets the magnitude V of the flow rate of the fluid to be measured to It is calculated as in the formula (Step 205).
- the process of step 205 is a process corresponding to the calculation of equation (42).
- the proportional coefficient rv is a constant that can be obtained in advance by calibration or the like.
- the signal conversion unit 5 and the flow rate output unit 6 perform the above-described processing of steps 201 to 205 at regular intervals until the operator instructs the end of the measurement (YES in step 206).
- a magnetic field including two components having the same magnitude and different frequencies is applied to the fluid to be measured from the excitation coil 3, and the angle of the electromotive force between the electrodes 2a and 2b is calculated.
- the difference between the electromotive force ⁇ 20 of the frequency ⁇ 0 component and the electromotive force E21 of the angular frequency ⁇ 1 component and the electromotive force ⁇ dA2 (dA / dt component vector Va) is extracted, and this 3 AZ 3 t component is
- the intermediate force between the EMFs E 20 composite vector Va + Vb
- the v XB component is extracted and the flow rate of the v XB component is calculated.
- the zero point of the output of the electromagnetic flowmeter can be corrected without having to perform the above operations, and the stability of the zero point can be ensured even in high-frequency excitation.
- the 3 X3 t component is removed from the electromotive force ⁇ 20 of the component of the angular frequency ⁇ to extract the v XB component.
- the electromotive force E21 of the component of the angular frequency ⁇ 1 The VXB component may be extracted by removing the 3 ⁇ 3t component from the inside.
- This embodiment uses the second extraction method as a method for extracting the estimated value Va ′ of the vector 3AZ3t component Va among the methods described in the above basic principle, and is subjected to an amplitude-modulated magnetic field. It is applied to the measurement fluid and extracts the estimated value Va 'of the 3AZ3t component vector Va using the difference between a plurality of frequency components included in the interelectrode electromotive force. Since the configuration of the electromagnetic flow meter of the present embodiment is the same as that of the electromagnetic flow meter of the first embodiment shown in FIG. 6, the principle of the present embodiment will be described using the reference numerals in FIG.
- Equation (51) b3 is the amplitude of the magnetic field B3
- ⁇ is the angular frequency of the carrier
- ⁇ is the angular frequency of the modulated wave
- ⁇ 3 is the phase difference (phase lag) between the carrier and coO't
- ma is the amplitude modulation index. It is.
- the magnetic flux density B3 is referred to as a magnetic field B3.
- Equation (51) can be transformed into the following equation.
- the interelectrode electromotive force that is caused by a change in the magnetic field and that is unrelated to the flow rate of the fluid to be measured will be described. Since the electromotive force due to the change in the magnetic field depends on the time derivative of the magnetic field, dBZdt, the magnetic field B3 generated from the exciting coil 3 is differentiated as in the following equation.
- dB3Zdt coO, b3 ' ⁇ sin ( ⁇ 3) ⁇ -cos ( w 0-t)
- the generated eddy current I has a direction as shown in FIG. 3, as in the first embodiment. Therefore, in a plane including the electrode axis EAX and the measurement tube axis PAX, the electromotive force E between the electrodes generated by the change of the magnetic field Ba and independent of the flow velocity has a direction as shown in FIG.
- the interelectrode electromotive force E is represented by the angular frequency components of ⁇ , ( ⁇ - ⁇ ), and ( ⁇ 0 + ⁇ 1) of the time derivative dB 3Zdt of the magnetic field considering the direction as shown in the following equation: Multiply by the proportional coefficient rk and replace it with the phase ⁇ 3 ⁇ ⁇ 3+ ⁇ 00 (where rk and ⁇ 00 are the conductivity and permittivity of the fluid to be measured and the measurement tube 1 including the arrangement of the electrodes 2a and 2b).
- rk and ⁇ 00 are the conductivity and permittivity of the fluid to be measured and the measurement tube 1 including the arrangement of the electrodes 2a and 2b.
- the generated eddy current includes the eddy current I when the flow velocity is 0.
- a component vXBa is generated due to the flow velocity vector v of the fluid to be measured.
- the eddy current Iv due to the flow velocity vector V and the magnetic field Ba has the direction shown in FIG. 4 as in the first embodiment. .
- the interelectrode electromotive force Ev due to the flow velocity is obtained by multiplying each angular frequency component of ⁇ 0, ( ⁇ - ⁇ ), ( ⁇ + ⁇ ) of the magnetic field ⁇ 3 by a proportional coefficient rkv as shown in the following equation.
- the phase 03 is replaced with 03 + 001 (rkv, ⁇ 01 is the structure of the measuring tube 1 including the magnitude V of the flow velocity, the conductivity and permittivity of the fluid to be measured, and the arrangement of the electrodes 2a and 2b. Involved).
- the electromotive force Ea3pc is obtained by applying the third and fourth terms of equation (54), the third and fourth terms of equation (55), and equation (20) as follows: Is represented by
- the electromotive force Ea3mc is obtained from the following equation by applying the fifth and sixth terms of equation (54), the fifth and sixth terms of equation (55), and equation (20). expressed.
- E3m is expressed by the following expression.
- Fig. 10 ⁇ shows a diagram in which the interelectrode electromotive force ⁇ 3 ⁇ , E3m is represented by a complex vector.
- E3p 3 A / dt in Fig. 10A is the dA / dt component (1Z2) ⁇ ma ⁇ rk ⁇ b3 ⁇ ex ⁇ ⁇ ] ⁇ ( ⁇ / 2 + ⁇ 3+ 0 ⁇ ) ⁇ ⁇ ( ⁇ + ⁇ 1), where E3m 3 ⁇ 3 t is the 3 AZ3t component (1Z2) 'ma'rk'b3'exp ⁇ j ⁇ ( ⁇ Z2 + ⁇ 3+ ⁇ 00) ⁇ ⁇ ( ⁇ 0— ⁇ 1), and E3pE3mv XB represents the v XB component in the interelectrode electromotive force E3p, E3m. If the difference between the interelectrode electromotive forces E3p and E3m is obtained, and the obtained difference is multiplied by (
- EdA3 (E3p-E3m) ⁇ ( ⁇ / ⁇ ) ⁇ (1 / ma)
- the electromotive force difference EdA3 shown in the equation (62) is not related to the magnitude V of the flow velocity, it is only a component generated by 3AZ3t.
- the interelectrode electromotive force E30 (composite vector Va + Vb) force vXB component is extracted using the electromotive force difference EdA3.
- the electromotive force difference EdA3 is exactly ( ⁇ 1) ⁇ (lZma) times the electromotive force difference between the electrode electromotive forces E3p and E3m, but is multiplied by ( ⁇ 1) ⁇ (lZma). The reason is to facilitate the expansion of the expression.
- the ⁇ component ⁇ 3 is not related to the angular frequencies ⁇ , ⁇ 1.
- the magnitude of the flow velocity When the V force is 0, the ⁇ ⁇ component ⁇ 3 also becomes 0.
- the force corrected by the 0 point can be obtained from the vXB component EvB3 so that the component force is obtained.
- Figure 10B shows a complex solid representation of the above electromotive force difference EdA3 and vXB component EvB3.
- equation (63) the magnitude and direction of the coefficient related to the magnitude V of the flow velocity are represented by the complex vector [ ⁇ 'rk'b3'exp ⁇ j '( ⁇ 3 + ⁇ 00 + ⁇ 01) ⁇ ].
- V I ⁇ 3 / [ ⁇ -rk-b3-exp ⁇ j- ( ⁇ 3+ ⁇ 00+ ⁇ ⁇ 01) ⁇ ]
- Table 3 shows the correspondence between the constants and variables used in the basic principle and the constants and variables of this embodiment. As is clear from Table 3, this embodiment is one example that specifically realizes the basic principle.
- the electromagnetic flow meter according to the present embodiment has a measuring tube 1, electrodes 2a and 2b, an exciting coil 3, a power supply unit 4, and an angular frequency ⁇ ⁇ + ⁇ ⁇ ⁇ ⁇ of the combined electromotive force detected by the electrodes 2a and 2b.
- ⁇ ⁇ The signal converter that determines the amplitude and phase of the two angular frequency components of ⁇ 1, and extracts the electromotive force difference between the two angular frequency components as a 3 ⁇ 3 t component based on these amplitudes and phases. 5 and a flow output unit 6 for extracting only the VXB component by removing the 3 ⁇ 3 t component from the component of the angular frequency ⁇ of the combined electromotive force and calculating the flow rate of the VXB component force fluid. .
- the power supply unit 4 supplies the exciting coil 3 with an exciting current obtained by amplitude-modulating a sine wave carrier having an angular frequency ⁇ with a sine wave modulated wave having an angular frequency ⁇ 1.
- the amplitude modulation index ma is an arbitrary value.
- FIG. 11 is a flowchart showing the operation of the signal conversion unit 5 and the flow rate output unit 6.
- the signal conversion unit 5 determines the amplitude r30 of the electromotive force E30 of the component of the angular frequency ⁇ among the electromotive forces between the electrodes 2a and 2b, and calculates the phase difference ⁇ 30 between the real axis and the interelectrode electromotive force E30. Is obtained by a phase detector (not shown).
- the signal conversion unit 5 obtains the amplitude r3p of the electromotive force ⁇ 3 ⁇ of the component of the angular frequency ( ⁇ 0 + ⁇ 1) of the electromotive force between the electrodes 2a and 2b, and also calculates the electromotive force E3p
- the phase difference ⁇ 3p is obtained by a phase detector.
- the signal converter 5 determines the amplitude r3m of the electromotive force E3m of the component of the angular frequency ( ⁇ 0- ⁇ 1) of the electromotive force between the electrodes 2a and 2b, and also calculates the electromotive force E3m between the real axis and the electrode.
- the phase difference ⁇ 3m is obtained by the phase detector (step 301 in Fig. 11).
- the interelectrode electromotive forces E30, E3p, and E3m can be frequency-separated by a bandpass filter. However, if a comb-shaped digital filter called a comb filter is used, three angular frequencies ⁇ ⁇ , ( ⁇ + ⁇ ), ( ⁇ 0— ⁇ 1).
- the signal conversion unit 5 generates a real axis component ⁇ 30 ⁇ of the interelectrode electromotive force ⁇ 30 and an imaginary axis component E30y, a real axis component E3px and an imaginary axis component E3py of the interelectrode electromotive force E3p, and an interelectrode electromotive force E3m.
- E3Ox r3O-cos (3O)... (65)
- the signal conversion unit 5 After calculating the equations (65) to (70), the signal conversion unit 5 obtains the magnitude of the electromotive force difference EdA3 between the interelectrode electromotive forces E3p and E3m (step 303).
- the process of step 303 is a process corresponding to obtaining the dA / dt component, and is a process corresponding to the calculation of equation (62).
- the signal converter 5 calculates the real axis component EdA3x and the imaginary axis component EdA3y of the electromotive force difference EdA3 as in the following equation.
- EdA3x (E3px-E3mx) ( ⁇ / ⁇ ) (1 / ma)
- EdA3y (E3py-E3my) ( ⁇ / ⁇ ) (l / ma) (72)
- the flow output unit 6 removes the electromotive force difference EdA3 from the interelectrode electromotive force E30, and obtains the magnitude of the vXB component EvB3 (step 304).
- the process of step 304 is a process corresponding to the calculation of equation (63).
- the flow output unit 6 calculates the magnitude I EvB3
- step 305 a process corresponding to the calculation of equation (64).
- V I EvB3 I / rv
- the proportional coefficient rv is a constant that can be obtained in advance by calibration or the like.
- the signal conversion unit 5 and the flow rate output unit 6 perform the processing of steps 301 to 305 at regular intervals until the operator instructs the end of the measurement (YES in step 306), for example.
- a magnetic field obtained by amplitude-modulating a carrier having an angular frequency ⁇ with a modulated wave having an angular frequency ⁇ 1 is applied to a fluid to be measured, and the electromotive force between the electrodes 2a and 2b is measured.
- the electromotive force ⁇ 3 ⁇ of the component of the angular frequency ( ⁇ 0+ ⁇ 1) and the electromotive force of the component of the angular frequency ( ⁇ 0— ⁇ 1) The electromotive force difference EdA3 (vector Va of dA / dt component) is extracted from m and the 3X3t component is removed by removing the neutral force between electrodes E30 (composite vector Va + Vb) to extract the vXB component. Since the vXB component force is used to calculate the flow rate of the fluid to be measured, the zero point of the output of the electromagnetic flowmeter can be corrected without setting the flow rate of the fluid to be measured to 0, and high-frequency excitation can be performed. In this case, the stability of the zero point can be ensured. Further, in the present embodiment, since it is not necessary to switch the excitation frequency as in the first embodiment, it is possible to calculate the flow rate at a higher speed.
- This embodiment uses the second extraction method as a method for extracting the estimated value Va ′ of the vector 3AZ3t component Va among the methods described in the above basic principle, and is subjected to an amplitude-modulated magnetic field. It is applied to the measurement fluid and extracts the estimated value Va 'of the 3AZ3t component vector Va using the difference between a plurality of frequency components included in the interelectrode electromotive force. Since the configuration of the electromagnetic flow meter of the present embodiment is the same as that of the electromagnetic flow meter of the first embodiment shown in FIG. 6, the principle of the present embodiment will be described using the reference numerals in FIG.
- EdA4 (E3p-E3m) ⁇ ( ⁇ / ⁇ )
- the electromotive force difference EdA4 shown in the equation (76) is not related to the magnitude V of the flow velocity, it is only a component generated by 3AZ3t.
- the vXB component is extracted from the electromotive force sum E3s (synthetic vector Va + Vb).
- the electromotive force difference EdA4 is, to be exact, the electromotive force difference between the interelectrode electromotive forces E3p and E3m multiplied by ( ⁇ ⁇ ⁇ 1).
- the reason for multiplying by ( ⁇ ⁇ ⁇ 1) is as follows. This is to facilitate deployment.
- VXB component obtained by subtracting the electromotive force difference EdA4 shown in Expression (76) from the electromotive force sum E3s shown in Expression (75) is EvB4
- the VXB component EvB4 is expressed by the following expression.
- EvB4 E3s-EdA4
- the vXB component ⁇ 4 is not related to the angular frequencies ⁇ , ⁇ 1.
- VXB component EvB4 can provide an output with zero-point correction so that the ⁇ ⁇ component ⁇ 4 also becomes 0 when the flow velocity magnitude V force is 0.
- FIG. 12A shows a diagram in which the interelectrode electromotive forces E3p and E3m are represented by complex vectors
- FIG. 12B shows a diagram in which the electromotive force sum E3s, the electromotive force difference EdA4, and the vXB component EvB4 are represented by complex vectors.
- E3pE3mvXB represents the vXB component in the interelectrode electromotive force E3p, E3m.
- equation (77) the magnitude and direction of the coefficient relating to the magnitude V of the flow velocity are represented by a complex vector [ma'y-rk-b3-exp ⁇ j- ( ⁇ 3 + ⁇ 00 + ⁇ 001) ⁇ ]. expressed.
- V I EvB4 / [ma- y -rk-b3-exp ⁇ j ⁇ ( ⁇ 3+ ⁇ 00+ ⁇ ⁇ 01) ⁇ ]
- Table 4 below shows the correspondence between the constants and variables used in the basic principle and the constants and variables in this embodiment. As is clear from Table 4, this embodiment is one example that specifically realizes the basic principle.
- the electromagnetic flow meter according to the present embodiment has a measuring tube 1, electrodes 2a and 2b, an exciting coil 3, a power supply unit 4, and an angular frequency ⁇ + ⁇ ⁇ ⁇ ⁇ of the combined electromotive force detected by the electrodes 2a and 2b.
- the signal converter 5 extracts the amplitude and phase of the two angular frequency components of ⁇ — ⁇ 1, and extracts the electromotive force difference between the two angular frequency components as a 3 ⁇ 3t component based on these amplitudes and phases. By removing the 3AZ3t component from the sum of the electromotive forces of the two angular frequency components in the combined electromotive force, only the vXB component is extracted, and the vXB component force is also used to calculate the flow rate of the fluid. And a quantity output unit 6.
- the power supply unit 4 supplies the exciting coil 3 with an exciting current obtained by amplitude-modulating a sine wave carrier having an angular frequency ⁇ with a sine wave modulated wave having an angular frequency ⁇ 1.
- the amplitude modulation index ma is an arbitrary value.
- FIG. 13 is a flowchart illustrating the operation of the signal conversion unit 5 and the flow rate output unit 6 according to the present embodiment.
- the signal conversion unit 5 obtains the amplitude r3p of the electromotive force ⁇ 3 ⁇ of the component of the angular frequency ( ⁇ ⁇ + ⁇ ⁇ ⁇ ⁇ ) of the electromotive force between the electrodes 2a and 2b, and calculates the relationship between the real axis and the interelectrode electromotive force E3p.
- the phase difference ⁇ 3p is obtained by a phase detector (not shown).
- the signal conversion unit 5 obtains the amplitude r3m of the electromotive force E3m of the component of the angular frequency ( ⁇ 0 ⁇ 1) of the electromotive force between the electrodes 2a and 2b,
- the phase difference ⁇ 3m is calculated using a phase detector (step 401 in Fig. 13).
- the interelectrode electromotive forces E3p and E3m can be frequency-separated by a bandpass filter or a comb filter.
- the signal conversion unit 5 calculates the real axis component E3px and the imaginary axis component E3py of the interelectrode electromotive force E3p, the real axis component E3mx and the imaginary axis component E3my of the interelectrode electromotive force E3m, and the sum of the electromotive force E3s.
- the real axis component E3sx and the imaginary axis component E3sy are calculated as in the following equation (step 402).
- the signal conversion unit 5 calculates the magnitude of the electromotive force difference EdA4 between the interelectrode electromotive forces E3p and E3m (Step 403).
- the process of step 403 is a process corresponding to obtaining the dA / dt component, and is a process corresponding to the calculation of equation (76).
- the signal conversion unit 5 calculates the real axis component EdA4x and the imaginary axis component EdA4y of the electromotive force difference EdA4 as in the following equation.
- EdA4x (E3px-E3mx) ⁇ ( ⁇ 0 / ⁇ 1)... (85)
- step 404 (E3py-E3my) ( ⁇ 0 / ⁇ 1)
- the flow output unit 6 removes the electromotive force difference EdA4 from the electromotive force sum E3s, and obtains the magnitude of the v XB component E vB4 (step 404).
- the process of step 404 is a process corresponding to the calculation of equation (77).
- the flow rate output unit 6 calculates the magnitude I EvB4
- V I EvB4 I / rv (88)
- the proportional coefficient rv is a constant that can be obtained in advance by calibration or the like.
- the signal conversion unit 5 and the flow rate output unit 6 perform the processing of steps 401 to 405 as described above at regular intervals, for example, until the operator instructs the end of measurement (YES in step 406).
- a magnetic field obtained by amplitude-modulating a carrier having an angular frequency ⁇ with a modulation wave having an angular frequency ⁇ 1 is applied to a fluid to be measured, and an electromotive force between the electrodes 2a and 2b is generated.
- the zero point of the output of the electromagnetic flowmeter can be corrected without setting the flow rate of the fluid to be measured to zero, and the stability of the zero point can be ensured even in high-frequency excitation.
- the present embodiment uses the second extraction method as a method for extracting the estimated value Va ′ of the vector Va of the 3AZ3t component among the methods described in the basic principle, and performs phase modulation or frequency modulation.
- a magnetic field is applied to the fluid to be measured, and the estimated value Va 'of the vector Va of the 3AZ3t component is extracted using the difference between a plurality of frequency components included in the electromotive force between the electrodes.
- Configuration of the electromagnetic flow meter of the present embodiment Is the same as that of the electromagnetic flow meter of the first embodiment shown in FIG. 6, and the principle of the present embodiment will be described using the reference numerals in FIG.
- a magnetic field component (magnetic flux density) B5 perpendicular to both the electrode axis EAX and the measurement tube axis PAX on the EAX is given as follows.
- b5 is the amplitude of the magnetic field B5
- ⁇ is the angular frequency of the carrier
- ⁇ is the angular frequency of the modulated wave
- 05 is the phase difference between the carrier and 0) 04 1! ⁇ 03 (0) 1'1 ( Phase delay)
- 11 ⁇ is a phase modulation index.
- the magnetic flux density ⁇ 5 is referred to as the magnetic field ⁇ 5.
- Equation (89) can be transformed as follows.
- the function iJ n (mp) is given by the following equation. [0137] [Number 2]
- the interelectrode electromotive force that is caused by a change in the magnetic field and that is not related to the flow velocity of the fluid to be measured will be described. Since the electromotive force due to the change in the magnetic field is based on the time differential dBZdt of the magnetic field, the magnetic field B5 generated from the exciting coil 3 is differentiated as in the following equation.
- the generated eddy current I has a direction as shown in FIG. 3, as in the first embodiment.
- the electromotive force E between the electrodes which is generated by the change of the magnetic field Ba and is independent of the flow velocity, is expressed as Each angular frequency component is multiplied by the proportional coefficient rk, and the phase 05 is replaced with 05 + 000 (rk, 000 is the conductivity and permittivity of the fluid to be measured and the measurement tube including the arrangement of the electrodes 2a and 2b). 1).
- E J (mp) * rk * coO'b5 ' ⁇ — sin ( ⁇ 5+ ⁇ 00) ⁇
- the interelectrode electromotive force resulting from the flow velocity of the fluid to be measured will be described.
- the generated eddy current includes the component vXBa due to the velocity vector V of the fluid to be measured, in addition to the eddy current I when the flow velocity is 0.
- the eddy current Iv due to the flow velocity V and the magnetic field Ba is oriented as shown in FIG. 4 as in the first embodiment.
- the interelectrode electromotive force Ev due to the flow velocity is represented by the following equation.
- 05 is replaced by 05 + 001 (rkv, ⁇ 01 is related to the structure of the measuring tube 1 including the magnitude V of the flow velocity, the conductivity and permittivity of the fluid to be measured, and the arrangement of the electrodes 2a and 2b. ).
- the electromotive force Ea50c of the component of the angular frequency ⁇ 0 is obtained from the first and second terms of the equation (96), the first and second terms of the equation (97), and the equation (20) by the following equation. expressed.
- E5m is expressed by the following equation.
- FIG. 14A shows a diagram in which the interelectrode electromotive force ⁇ 5 ⁇ , E5m is represented by a complex vector.
- E5p dA / dt is the 3 AZ 3t component J (mp) -rk-b5-exp ⁇ j
- E5pE5mvXB represents the ⁇ component in the interelectrode electromotive force E5p, E5m.
- the difference between the electromotive forces E5p and E5m between the electrodes is calculated, and the obtained difference is calculated as ( ⁇ OZ ⁇ l) ⁇ J (mp) / ⁇ 2-J (mp) ⁇ ⁇
- EdA5 (E5p-E5m) ( ⁇ / ⁇ 1) -J (mp)
- the electromotive force difference EdA5 shown in the equation (104) is not related to the magnitude V of the flow velocity, it is only a component generated by 3AZ3t.
- the interelectrode electromotive force E50 (composite vector Va + Vb) force vXB component is extracted using the electromotive force difference EdA5.
- the electromotive force difference EdA5 is precisely the electromotive force difference between the interelectrode electromotive forces E5p and E5m as ( ⁇ OZ ⁇ l) ⁇ J (mp) / ⁇ 2-J (mpM'exp
- EvB5 E50-EdA5
- vXB component EvB5 does not relate to the angular frequencies ⁇ , ⁇ 1.
- the magnitude of the flow velocity When the V force is 0, the ⁇ ⁇ component ⁇ 5 also becomes 0.
- the force corrected by the vXB component EvB5 can be obtained from the vXB component EvB5.
- Figure 14B shows a complex vector representation of the interelectrode electromotive force E50, electromotive force difference EdA5, and vXB component EvB5. According to equation (105), the magnitude and direction of the coefficient relating to the magnitude V of the flow velocity are represented by the complex vector Q [(mp) ⁇ y -rk-bS-expij
- V I EvB5 / [T (mp) ⁇ -rk-b5
- Table 5 below shows the correspondence between the constants and variables used in the basic principle and the constants and variables in this embodiment. As is clear from Table 5, this embodiment is one example that specifically realizes the basic principle.
- the electromagnetic flow meter according to the present embodiment includes a measuring tube 1, electrodes 2a and 2b, an exciting coil 3, a power supply unit 4, and an angular frequency ⁇ of the combined electromotive force detected by the electrodes 2a and 2b.
- ⁇ 1 ( ⁇ is a positive integer) component Neutral force Finds the amplitude and phase of two different angular frequency components, and calculates the difference in electromotive force between the two angular frequency components based on these amplitudes and phases by 3 ⁇ 3 t By extracting the 3 ⁇ ⁇ 3t component from any one of the components of the signal conversion unit 5 to be extracted as a component and the angular frequency ⁇ and ⁇ a flow output unit 6 for extracting only the ⁇ ⁇ component and calculating the flow rate of the vX B component force fluid.
- the power supply unit 4 supplies the exciting coil 3 with an exciting current obtained by phase-modulating a sine wave carrier having an angular frequency ⁇ with a sine wave modulated wave having an angular frequency ⁇ 1.
- the phase modulation index mp is an arbitrary value.
- the signal converter 5 calculates the amplitude r50 of the electromotive force E50 of the component of the angular frequency ⁇ 0 of the electromotive force between the electrodes 2a and 2b, and calculates the phase difference ⁇ 50 between the real axis and the interelectrode electromotive force E50. Determined by a phase detector (not shown).
- the signal converter 5 obtains the amplitude r5p of the electromotive force ⁇ 5 ⁇ of the component of the angular frequency ( ⁇ 0 + ⁇ 1) of the electromotive force between the electrodes 2a and 2b, and calculates the electromotive force E5p between the real axis and the electrode. Is obtained by a phase detector. Further, the signal conversion unit 5 obtains the amplitude r5m of the electromotive force E5m of the component of the angular frequency ( ⁇ 0 ⁇ 1) of the electromotive force between the electrodes 2a and 2b, and calculates the amplitude of the electromotive force E5m between the real axis and the electrode. The phase difference ⁇ 5m is determined by the phase detector (step 301 in Fig. 11). The interelectrode electromotive forces E50, E5p, and E5m can be frequency-separated by a bandpass filter / comb filter.
- the signal conversion unit 5 generates a real axis component E50x and an imaginary axis component E50y of the interelectrode electromotive force E50, a real axis component E5px and an imaginary axis component E5py of the interelectrode electromotive force E5p, and an interelectrode electromotive force E5m.
- the real axis component E5mx and the imaginary axis component E5my are calculated as follows (step 302).
- E50y r50- sin ((i) 50)
- E5px r5p'cos (5p)... (109)
- the signal conversion unit 5 calculates the magnitude of the electromotive force difference EdA5 between the interelectrode electromotive forces E5p and E5m (Step 303).
- the processing in step 303 is processing corresponding to obtaining the 3 AZ d t component, and is processing corresponding to the calculation of equation (104).
- the signal converter 5 calculates the real axis component EdA5x and the imaginary axis component EdA5y of the electromotive force difference EdA5 as in the following equation.
- Vessel relations (mp) and J (mp) are arbitrary set values.
- EdA5x (E5px-E5mx) ⁇ ( ⁇ / ⁇ ) -J (mp)
- EdA5y (E5py-E5my) ( ⁇ / ⁇ 1) -J (mp)
- the flow rate output unit 6 removes the electromotive force difference EdA5 from the interelectrode electromotive force ⁇ 50, and obtains the magnitude of the vXB component EvB5 (step 304).
- the process of step 304 is a process corresponding to the calculation of equation (105).
- the flow output section 6 has the size of the vXB component EvB5
- EvB5 I ⁇ (E50x-EdA5x) 2 + (E50y-EdA5y) 2 ⁇ 1/2 (115)
- the flow rate output unit 6 calculates the magnitude V of the flow velocity of the fluid to be measured as in the following equation (Step 305).
- the process of step 305 is a process corresponding to the calculation of equation (106).
- V I EvB5 I / rv (116)
- the proportional coefficient rv is a constant that can be obtained in advance by calibration or the like, and the Bessel comfort (mp) included in the proportional coefficient rv is an arbitrary set value.
- Signal converter 5 and flow rate are a constant that can be obtained in advance by calibration or the like, and the Bessel comfort (mp) included in the proportional coefficient rv is an arbitrary set value.
- the output unit 6 performs the processing of steps 301 to 305 as described above at regular intervals until, for example, the operator instructs the end of measurement (YES in step 306).
- the magnetic field obtained by phase-modulating the carrier having the angular frequency ⁇ with the modulation wave having the angular frequency ⁇ 1 is applied to the fluid to be measured, and the electromotive force between the electrodes 2a and 2b is measured.
- the electromotive force ⁇ 5 ⁇ of the component of the angular frequency ( ⁇ 0+ ⁇ 1) and the electromotive force ⁇ 5 of the component of the angular frequency ( ⁇ 0— ⁇ 1) Extract the electromotive force difference EdA5 (vector Va of the dA / dt component) from m and extract the vXB component by removing the 3AZ3t component from the neutral force E50 between the electrodes (composite vector Va + Vb).
- the zero point of the output of the electromagnetic flowmeter can be corrected without setting the flow rate of the fluid to be measured to 0, and high-frequency excitation can be performed. In this case, the stability of the zero point can be ensured. Further, in the present embodiment, since it is not necessary to switch the excitation frequency as in the first embodiment, it is possible to calculate the flow rate at a higher speed.
- the 3 ⁇ 3 t component is removed from the electromotive force E50 of the component of the angular frequency ⁇ , but the electromotive force of the component of the angular frequency ( ⁇ 0 + ⁇ 1) ⁇ 5 ⁇ From this, the 3 ⁇ 3t component may be removed, or the dA / dt component may be removed from the electromotive force E5m of the component of the angular frequency ( ⁇ 0- ⁇ 1).
- an excitation current obtained by phase-modulating a sine-wave carrier having an angular frequency ⁇ with a sine-wave modulated wave having an angular frequency ⁇ 1 is supplied from the power supply section 4 to the excitation coil 3.
- the excitation current obtained by frequency-modulating the sine-wave carrier having the angular frequency ⁇ by the sine-wave modulation wave having the angular frequency ⁇ 1 may be supplied to the excitation coil 3.
- the magnetic field component (magnetic flux density) B5 perpendicular to both the electrode axis EAX and the measurement tube axis PAX on the electrode axis EAX connecting the electrodes 2a and 2b, of the magnetic field generated from the excitation coil 3 is as follows: Shall be given as
- b5 is amplitude, ⁇ , ⁇ are angular frequencies, 05 is a phase difference (phase delay) from ⁇ -t—mf'sin (co 1 • t), and mf is a frequency modulation index.
- Equation (117) can be transformed into the following equation.
- the Bessel function iJ n (mf) is given by the following equation.
- Equation (119) can be transformed as follows.
- the present embodiment uses the second extraction method as a method for extracting the estimated value Va ′ of the vector Va of the 3AZ3t component among the methods described in the basic principle, and performs phase modulation or frequency modulation.
- a magnetic field is applied to the fluid to be measured, and the estimated value Va 'of the vector Va of the 3AZ3t component is extracted using the difference between a plurality of frequency components included in the electromotive force between the electrodes. Since the configuration of the electromagnetic flow meter of the present embodiment is the same as that of the electromagnetic flow meter of the first embodiment shown in FIG. 6, the principle of the present embodiment will be described using the reference numerals in FIG.
- EdA6 (E5p-E5m) ⁇ ( ⁇ / ⁇ )
- the electromotive force difference EdA6 shown in the equation (125) is not related to the magnitude V of the flow velocity, it is only a component generated by 3AZ3t.
- the vXB component is also extracted from the electromotive force sum E5s (synthetic beta + Vb) force.
- the electromotive force difference EdA6 is exactly the electromotive force difference between the interelectrode electromotive forces E5p and E5m multiplied by ( ⁇ 0 / ⁇ 1).
- the reason for multiplying by ( ⁇ 1) is as follows: This is for facilitating the development of the application.
- EvB6 E5s-EdA6
- the vXB component ⁇ 6 is not related to the angular frequencies ⁇ , ⁇ 1.
- the force corrected by the 0 point can be obtained from the vXB component EvB6 so that the force component can be obtained.
- Figure 15A shows a complex vector representation of the interelectrode electromotive forces E5p and E5m
- Figure 15B shows a complex vector representation of the electromotive force sum E5s, the electromotive force difference EdA6, and the vXB component EvB6.
- E5p d A / dt in Fig. 15A is the 3AZ3t component J (mp) 'rk'b5'exp ⁇ j
- E5pE5mv X B represents the vXB component in the interelectrode electromotive force E5p, E5m.
- equation (126) the magnitude and direction of the coefficient on the magnitude V of the flow velocity are represented by the complex vector [2'J (mp) ⁇ ⁇ -rk-b5-exp ⁇ j ⁇ ( ⁇ / 2 + ⁇ 5 + ⁇ 0
- V I EvB6 / [2-J (mp) y-rk-b5
- Table 6 below shows the correspondence between the constants and variables used in the basic principle and the constants and variables of the present embodiment. As is clear from Table 6, this embodiment is one example that specifically realizes the basic principle.
- the electromagnetic flow meter according to the present embodiment includes a measuring tube 1, electrodes 2a and 2b, an exciting coil 3, a power supply unit 4, and an angular frequency ⁇ of the combined electromotive force detected by the electrodes 2a and 2b. Find the amplitude and phase of two different angular frequency components ( ⁇ is a positive integer), and determine the electromotive force difference between the two angular frequency components as 3 ⁇ 3 t based on these amplitudes and phases.
- a signal conversion unit 5 that extracts and extracts the component of the angular frequency ⁇ It has a flow output unit 6 that extracts only the v XB component by removing the 3 AZ 3 t component from the sum of the electromotive forces of the two angular frequency components, and calculates the v XB component force fluid flow rate.
- the power supply unit 4 supplies the excitation coil 3 with an excitation current obtained by phase-modulating or frequency-modulating the sine-wave carrier having the angular frequency ⁇ with the sine-wave modulated wave having the angular frequency ⁇ 1.
- the phase modulation index mp is an arbitrary value.
- the signal converter 5 determines the amplitude r5p of the component of the angular frequency ( ⁇ 0 + ⁇ 1) of the component of the electromotive force between the electrodes 2a and 2b, and the amplitude r5p of the real axis and the interelectrode electromotive force E5p.
- the phase difference ⁇ 5 ⁇ is determined by a phase detector (not shown).
- the signal converter 5 obtains the amplitude r5m of the electromotive force E5m of the component of the angular frequency ( ⁇ 0 ⁇ 1) of the electromotive force between the electrodes 2a and 2b, and calculates the difference between the real axis and the interelectrode electromotive force E5m.
- the phase difference ⁇ 5m is obtained by the phase detector (step 401 in FIG. 13).
- the interelectrode electromotive forces E5p and E5m can be frequency-separated by a bandpass filter or a comb filter.
- the signal conversion unit 5 calculates the real axis component E5px and the imaginary axis component E5py of the interelectrode electromotive force E5p, the real axis component E5mx and the imaginary axis component E5my of the interelectrode electromotive force E5m, and the sum of the electromotive force E5s.
- the real axis component E5sx and the imaginary axis component E5sy are calculated as in the following equation (step 402).
- the signal converter 5 calculates the magnitude of the electromotive force difference EdA6 between the interelectrode electromotive forces E5p and E5m (step 403).
- the process of step 403 is a process corresponding to obtaining the 3 AZ dt component, and is a process corresponding to the calculation of equation (125).
- the signal converter 5 converts the real axis component EdA6x and the imaginary axis component EdA6y of the electromotive force difference EdA6 into the following equation. Is calculated as follows.
- EdA6x (E5px-E5mx) ( ⁇ / ⁇ ) (134)
- EdA6y (E5py-E5my) ( ⁇ / ⁇ ) (135)
- the flow rate output unit 6 removes the electromotive force difference EdA6 from the electromotive force sum E5s, and obtains the magnitude of the vXB component E vB6 (step 404).
- the process of step 404 is a process corresponding to the calculation of equation (126).
- the flow output unit 6 calculates the magnitude I EvB6
- step 405 a process corresponding to the calculation of equation (127).
- V I EvB6 I / rv
- the proportional coefficient rv is a constant that can be obtained in advance by calibration or the like, and the Bessel comfort (mp) included in the proportional coefficient rv is an arbitrary set value.
- the signal conversion unit 5 and the flow rate output unit 6 perform the processing of steps 401 to 405 described above at regular intervals until, for example, the operator instructs the end of the measurement (YES in step 406).
- a magnetic field in which a carrier having an angular frequency ⁇ is phase-modulated or frequency-modulated by a modulated wave having an angular frequency ⁇ 1 is applied to a fluid to be measured, and a magnetic field between the electrodes 2a and 2b is applied.
- the electromotive force difference EdA6 (dA / dt component vector Va) is obtained from the electromotive force ⁇ 5 ⁇ of the angular frequency ( ⁇ 0 + ⁇ 1) component of the electromotive force and the electromotive force E5m of the angular frequency ( ⁇ 0— ⁇ 1) component.
- the zero point of the output of the electromagnetic flowmeter can be corrected without setting the flow rate of the fluid to be measured to zero, and the stability of the zero point can be ensured even in high-frequency excitation. Further, in the present embodiment, since it is not necessary to switch the excitation frequency as in the first embodiment, it is possible to calculate the flow rate at a higher speed.
- the essence of the present invention is to provide a method for removing the 3AZ3t component from the combined vector Va + Vb regardless of the structure of the electromagnetic flowmeter.
- the dA / dt component induced in the fluid to be measured the dA / dt component induced directly to the electrode, and the It is possible to remove 3 AZ 3 components regardless of where they are induced, such as 3 AZ 3 components.
- the measurement is performed in the electromagnetic flowmeter having a structure in which the excitation coil is disposed at a position separated from the electrode axis by the offset distance d in the direction of the measurement tube axis.
- the operation of removing the 3AZ3 component generated in the fluid has been described, but the present invention is not limited to this, and the present invention can be applied to an electromagnetic flowmeter having another configuration.
- the sine wave excitation method using a sine wave as the excitation current is employed.
- the rectangular wave excitation method using a rectangular wave as the excitation current may be employed.
- the electrodes 2a and 2b used in the first to sixth embodiments may be electrodes of a type exposed from the inner wall of the measuring tube 1 and in contact with the fluid to be measured, As shown in FIG. 17, a capacitively coupled electrode that does not contact the fluid to be measured may be used.
- the electrodes 2a and 2b are covered with a lining 10 formed on the inner wall of the measuring tube 1 such as ceramic or Teflon (registered trademark).
- the force using the pair of electrodes 2a and 2b may be one that is not limited to this.
- a ground ring or a ground electrode for setting the potential of the fluid to be measured to the ground potential is provided in the measuring tube 1, and the electromotive force generated at one electrode (ground potential and The potential difference may be detected by the signal converter 5.
- the electrode axis is a straight line connecting the pair of electrodes.
- the plane PLN including this one real electrode assuming that a virtual electrode is placed at a position facing the real electrode across the measurement tube axis PAX, The straight line connecting the electrode and the virtual electrode is the electrode axis.
- the configuration of the signal conversion unit 5 and the flow output unit 6 other than the detection of the electromotive force is a computer having a CPU, a storage device, and an interface. It can be realized by a program that controls these hardware resources.
- the present invention can be applied to flow rate measurement of a fluid to be measured flowing in a measurement tube.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US11/628,556 US7496455B2 (en) | 2004-06-14 | 2005-06-10 | Electromagnetic flowmeter |
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JP2004175630A JP4523343B2 (ja) | 2004-06-14 | 2004-06-14 | 電磁流量計 |
JP2004-175630 | 2004-06-14 |
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WO2005121716A1 true WO2005121716A1 (ja) | 2005-12-22 |
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PCT/JP2005/010684 WO2005121716A1 (ja) | 2004-06-14 | 2005-06-10 | 電磁流量計 |
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US (1) | US7496455B2 (ja) |
JP (1) | JP4523343B2 (ja) |
CN (1) | CN100434873C (ja) |
WO (1) | WO2005121716A1 (ja) |
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JP4523318B2 (ja) * | 2004-04-09 | 2010-08-11 | 株式会社山武 | 電磁流量計 |
JP4523319B2 (ja) * | 2004-04-09 | 2010-08-11 | 株式会社山武 | 電磁流量計 |
JP4465725B2 (ja) * | 2008-04-04 | 2010-05-19 | 株式会社デンソー | 液体用濃度測定装置 |
JP5391000B2 (ja) * | 2009-09-04 | 2014-01-15 | アズビル株式会社 | 電磁流量計 |
JP5385064B2 (ja) * | 2009-09-09 | 2014-01-08 | アズビル株式会社 | 電磁流量計 |
DE102015120103B4 (de) * | 2015-11-19 | 2018-09-13 | Krohne Ag | Verfahren zur Durchflussmessung durch ein magnetisch-induktives Durchflussmessgerät |
CN106092227A (zh) * | 2016-07-22 | 2016-11-09 | 无锡信大气象传感网科技有限公司 | 基于三级放大电路及电源管理器的液体体积流量监控系统 |
SG11201901955WA (en) * | 2016-10-04 | 2019-04-29 | Micro Motion Inc | Flowmeter calibration method and related apparatus |
JP6839635B2 (ja) | 2017-09-14 | 2021-03-10 | アズビル株式会社 | 電磁流量計の誤差検出回路および誤差検出方法ならびに電磁流量計 |
JP7294875B2 (ja) * | 2019-05-10 | 2023-06-20 | アズビル株式会社 | 容量式電磁流量計 |
CN113447099B (zh) * | 2021-06-25 | 2023-04-07 | 上海肯特仪表股份有限公司 | 一种电磁水表的自动零点修正方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2003027614A1 (fr) * | 2001-09-20 | 2003-04-03 | Yamatake Corporation | Fluxmetre electromagnetique |
JP2004108973A (ja) * | 2002-09-19 | 2004-04-08 | Yamatake Corp | 電磁流量計 |
JP2004108975A (ja) * | 2002-09-19 | 2004-04-08 | Yamatake Corp | 電磁流量計 |
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US5625155A (en) * | 1901-09-03 | 1997-04-29 | Aichi Tokei Denki Co., Ltd. | Electromagnetic flowmeter |
US4408497A (en) * | 1981-12-22 | 1983-10-11 | Hokushin Electric Works, Ltd. | Electromagnetic flowmeter for measuring ferromagnetic slurries |
JPS60173024U (ja) * | 1984-04-26 | 1985-11-16 | 株式会社東芝 | 電磁流量計 |
FR2589571B1 (fr) * | 1985-10-31 | 1990-02-09 | Sereg Soc | Debitmetre electromagnetique a champ magnetique pulse |
US5426984A (en) * | 1993-09-02 | 1995-06-27 | Rosemount Inc. | Magnetic flowmeter with empty pipe detector |
JP4523318B2 (ja) * | 2004-04-09 | 2010-08-11 | 株式会社山武 | 電磁流量計 |
-
2004
- 2004-06-14 JP JP2004175630A patent/JP4523343B2/ja not_active Expired - Fee Related
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2005
- 2005-06-10 US US11/628,556 patent/US7496455B2/en not_active Expired - Fee Related
- 2005-06-10 CN CNB2005800275732A patent/CN100434873C/zh not_active Expired - Fee Related
- 2005-06-10 WO PCT/JP2005/010684 patent/WO2005121716A1/ja active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2003027614A1 (fr) * | 2001-09-20 | 2003-04-03 | Yamatake Corporation | Fluxmetre electromagnetique |
JP2004108973A (ja) * | 2002-09-19 | 2004-04-08 | Yamatake Corp | 電磁流量計 |
JP2004108975A (ja) * | 2002-09-19 | 2004-04-08 | Yamatake Corp | 電磁流量計 |
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JP4523343B2 (ja) | 2010-08-11 |
US20070234820A1 (en) | 2007-10-11 |
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CN101006327A (zh) | 2007-07-25 |
US7496455B2 (en) | 2009-02-24 |
JP2005351852A (ja) | 2005-12-22 |
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