WO2016189748A1 - Débitmètre électromagnétique - Google Patents

Débitmètre électromagnétique Download PDF

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Publication number
WO2016189748A1
WO2016189748A1 PCT/JP2015/065474 JP2015065474W WO2016189748A1 WO 2016189748 A1 WO2016189748 A1 WO 2016189748A1 JP 2015065474 W JP2015065474 W JP 2015065474W WO 2016189748 A1 WO2016189748 A1 WO 2016189748A1
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Prior art keywords
mode
amplifying device
flow rate
amplifying
noise
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PCT/JP2015/065474
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English (en)
Japanese (ja)
Inventor
森　和久
淳憲 青山
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Aichi Tokei Denki Co Ltd
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Aichi Tokei Denki Co Ltd
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Priority to PCT/JP2015/065474 priority Critical patent/WO2016189748A1/fr
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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
    • G01F1/60—Circuits therefor

Definitions

  • This specification discloses an electromagnetic flow meter.
  • Japanese Unexamined Patent Publication No. 2001-324361 discloses an electromagnetic flow meter.
  • the electromagnetic flow meter includes a tube, a pair of electrodes fixed to the tube, an amplifying device that amplifies a voltage generated between the electrodes, and a control device.
  • a voltage is generated between the electrodes.
  • the voltage varies with the flow rate of the fluid passing between the electrodes.
  • the voltage is amplified by the amplification device.
  • the control device converts the amplified voltage into a flow rate of the fluid passing through the pipe.
  • the flow rate here refers to the volume of fluid passing through the pipe per unit time. If the flow rate is integrated with respect to time, the volume of the fluid that has passed through the tube can be obtained.
  • the control device outputs the volume.
  • the electromagnetic flow meter requires inspection to verify the accuracy of the output result.
  • a fluid having a known flow rate is passed through an electromagnetic flow meter, and it is verified whether a volume corresponding to the flow rate and the elapsed time is output from the electromagnetic flow meter.
  • the flow rate of the fluid flowing for the inspection is referred to as the inspection flow rate.
  • the noise amplified by the amplifier will contain noise. As a result, noise is also included in the flow rate or volume detection result obtained from the amplified voltage.
  • the electromagnetic flow meter outputs only the volume, it is possible to know the flow rate obtained from the amplified voltage by differentiating the volume with time.
  • the flow rate obtained from the amplified voltage is referred to as the detected flow rate.
  • noise is included in the detected flow rate.
  • An accurate inspection cannot be performed by simply comparing the detected flow rate and the inspection flow rate. Even if the detected flow rate matches the inspection flow rate, the detection flow rate does not match the inspection flow rate because it matches due to the influence of noise. In that case, a defective product is erroneously determined as a non-defective product. Conversely, even if the inspection flow rate and the detected flow rate do not match, they are mismatched due to the influence of noise, and the detected flow rate from which the influence of noise has been removed may match the inspection flow rate. In that case, a non-defective product is erroneously determined as a defective product.
  • the amplified voltage is a noise superimposed on a voltage that is not affected by the noise, and the superimposed noise takes positive and negative values.
  • the noise generated by the amplifying device it is known that the positive and negative appearance ratios are equal, and it is known that the influence of noise can be removed if averaged over a long period of time.
  • the number of samplings required to remove the influence of noise varies depending on the magnitude of the influence of noise. For example, it is assumed that the amplified voltage that is not affected by noise is 1 volt, and the magnitude of noise superimposed on the amplified voltage is 0.3 volt. That is, when sampling, a value of 130% of the true value may be sampled, or a value of 70% of the true value may be sampled. In this case, in order to guarantee a relationship in which the average value falls within the range of, for example, 105 to 95% of the true average value, it is necessary to average by taking a large number of samplings.
  • the amplified voltage that is not affected by noise is 5 volts
  • the magnitude of noise superimposed on the amplified voltage is 0.3 volts. That is, when sampling, a value of 106% of the true value may be sampled, or a value of 94% of the true value may be sampled. In this case, since the relationship in which the average value is within the range of 105 to 95% of the true average value is guaranteed, the number of samplings required is small.
  • the magnitude of the noise produced by the amplification device does not depend on the magnitude of the amplified voltage that is not affected by the noise. In the above example, the magnitude of noise is 0.3 volts regardless of whether the amplified voltage is 1 volt or 5 volts.
  • the specific numerical value varies depending on the type of the electromagnetic flow meter, the tendency that the magnitude of the noise is almost uniform is a characteristic generally recognized in the electromagnetic flow meter.
  • the electromagnetic flow meter When actually using an electromagnetic flow meter, the noise introduced by the amplifying device does not affect the actually required result.
  • the electromagnetic flow meter outputs a volume obtained by integrating the flow rate. This is because the influence of noise is removed by averaging during integration.
  • This specification discloses an electromagnetic flow meter that can solve the problem that inspection, particularly small flow inspection, takes time.
  • the electromagnetic flow meter disclosed in the present specification detects the flow rate of the fluid flowing in the pipe.
  • the electromagnetic flow meter includes a pair of electrodes fixed to a tube, a first amplifying device connected to the pair of electrodes and amplifying a voltage generated between the electrodes, and a pair in parallel with the first amplifying device. And a second amplifying device that amplifies the voltage between the electrodes.
  • the electromagnetic flow meter includes a battery that supplies power to the first amplification device and the second amplification device, and a control device.
  • the current consumption of the first amplifying device is smaller than the current consumption of the second amplifying device.
  • the noise of the second amplifying device is smaller than the noise of the first amplifying device.
  • the control device is configured to be switchable between a first mode for calculating the flow rate based on the voltage amplified by the first amplifying device and a second mode for calculating the flow rate based on the voltage amplified by the second amplifying device. ing.
  • the control device switches between the first mode and the second mode. For example, when the electromagnetic flow meter is normally used, the mode is switched to the first mode, and when the electromagnetic flow meter is inspected, the mode is switched to the second mode. Alternatively, the mode is switched to the first mode at the time of the large flow rate inspection, and the second mode is switched at the time of the small flow rate inspection. Thus, the first mode and the second mode can be used depending on the situation.
  • a voltage is generated between the electrodes when the fluid passes between the pair of electrodes. The generated voltage is amplified by the first amplification device (first mode) or the second amplification device (second mode). The control device calculates the flow rate of the fluid based on the voltage amplified by the first amplification device or the second amplification device.
  • the current consumption of the first amplifying device is smaller than the current consumption of the second amplifying device. Therefore, the current consumption can be suppressed by using the first mode in which the voltage between the electrodes is amplified by the first amplifying device. For example, the current consumption can be suppressed by using the first mode during normal use of the electromagnetic flow meter or during a large flow inspection. As a result, battery consumption can be suppressed.
  • noise is generated in each of the first amplifying device and the second amplifying device. Therefore, the voltage amplified by the first amplification device or the second amplification device is affected by noise.
  • the noise of the second amplifying device is smaller than the noise of the first amplifying device. Therefore, when using the second amplifying device, the magnitude of noise relative to the significant voltage is relatively small, and the influence of noise is relatively small. The number of samplings required to remove the influence of noise can be reduced, and the time required to remove the influence of noise can be shortened. It is possible to complete a small flow rate inspection in which the inspection time is particularly long in a short time.
  • the reliability of the flow rate of the fluid is measured without measuring a large number of flow rates when the flow rate of the fluid is measured over a predetermined time to obtain an average value of a plurality of flow rates. There can be an average value. As a result, a reliable average value can be obtained with a few flow rates. Therefore, a reliable flow rate can be obtained in a short time by using the second mode. For example, a reliable flow rate can be obtained in a short time by using the second mode at the time of inspection of the electromagnetic flow meter or at least at the time of small flow rate inspection.
  • the first mode and the second mode can be used, so that a reliable flow rate can be obtained in a short time while suppressing battery consumption.
  • control device switches between the first mode and the second mode according to the flow rate of the fluid.
  • the fluid flow rate in the second mode is preferably smaller than the fluid flow rate in the first mode.
  • the second mode can be used when the flow rate of the fluid flowing through the pipe is small.
  • the voltage generated between the pair of electrodes is small.
  • the magnitude of noise with respect to voltage can be made relatively small.
  • the second amplifying device can operate in the normal mode and the sleep mode in which the current consumption is smaller than that in the normal mode.
  • the control device switches from the second mode to the first mode, it is preferable to switch the second amplifying device from the normal mode to the sleep mode.
  • the current consumption of the second amplifying device can be suppressed by using the sleep mode.
  • control device is connected to an operation device that switches between the first mode and the second mode.
  • the operator can select the first mode and the second mode via the operation device.
  • the first mode and the second mode can be used depending on the situation by the operator's selection.
  • control device is connected to an operation device that switches between a normal use state and an inspection state.
  • the control device preferably selects the first mode.
  • the control device selects the second mode during the small flow rate inspection, and the control device selects the first mode during the large flow rate inspection.
  • the operator can select the normal use state and the inspection state via the operation device.
  • the operator can select the normal use state during normal use of the electromagnetic flow meter, and can select the inspection state during inspection of the electromagnetic flow meter.
  • the first mode can be used during normal use of the electromagnetic flow meter under the control of the control device.
  • the first mode and the second mode can be used when inspecting the electromagnetic flow meter.
  • the second mode can be used for a small flow rate inspection with a small fluid flow rate
  • the first mode can be used for a large flow rate inspection with a large fluid flow rate.
  • the electromagnetic flow meter 1 includes a tube 10 and a pair of electrodes 11 a and 11 b fixed to the tube 10.
  • the electromagnetic flow meter 1 includes a first amplifying device 21 connected to the pair of electrodes 11a and 11b and a second amplifying device connected to the pair of electrodes 11a and 11b in parallel with the first amplifying device 21.
  • a device 22 is provided.
  • the electromagnetic flow meter 1 includes a control device 50 and a battery 30.
  • the tube 10 has a circular cross section. An insulating lining is formed on the inner surface of the tube 10.
  • the inside of the tube 10 is filled with fluid.
  • a fluid is flowing inside the tube 10.
  • An example of the fluid is water.
  • the electromagnetic flow meter 1 is used for a water meter, for example.
  • the tube 10 is disposed in the magnetic field B. A fluid flows in the magnetic field B.
  • a magnetic field B generated by an excitation coil (not shown) acts on the fluid flowing inside the tube 10.
  • the tube 10 is arranged so as to extend in a direction orthogonal to the direction of the magnetic field B. The fluid flows in a direction perpendicular to the direction of the magnetic field B.
  • the pair of electrodes 11a and 11b face each other.
  • the pair of electrodes 11a and 11b oppose each other in a direction orthogonal to the direction of the fluid flowing through the tube 10 (the direction in which the tube 10 extends).
  • the pair of electrodes 11 a and 11 b face each other in a direction orthogonal to the direction of the magnetic field B.
  • the pair of electrodes 11 a and 11 b are exposed inside the tube 10.
  • the pair of electrodes 11 a and 11 b are in contact with the fluid in the tube 10.
  • the pair of electrodes 11a and 11b are opposed to each other with the fluid in the tube 10 interposed therebetween.
  • a fluid flows between the pair of electrodes 11a and 11b.
  • the first amplifying device 21 and the second amplifying device 22 are connected in parallel to the pair of electrodes 11a and 11b.
  • a known operational amplifier can be used as the first amplifying device 21.
  • the first amplifying device 21 includes a non-inverting input terminal 71, an inverting input terminal 72, an output terminal 74, and a resistor 75.
  • the first amplifying device 21 amplifies the difference between the non-inverting input terminal 71 and the inverting input terminal 72 by a constant coefficient.
  • the first amplifying device 21 amplifies and outputs an input signal.
  • the first amplifying device 21 amplifies a voltage generated between the pair of electrodes 11a and 11b. In the first amplifying device 21, noise is generated.
  • the voltage amplified by the first amplifying device 21 is affected by noise during amplification.
  • the first amplification device 21 is disposed in the casing 90.
  • the first amplifying device 21 can operate in a normal mode and a sleep mode.
  • the first amplifying device 21 operates in any mode by switching between the normal mode and the sleep mode.
  • the current consumption in the normal mode is different from the current consumption in the sleep mode.
  • the current consumption of the first amplification device 21 in the sleep mode is smaller than the current consumption of the first amplification device 21 in the normal mode.
  • the first amplifying device 21 includes a plurality of first switches 65. When the first switch 65 is on, signals are input from the electrodes 11 a and 11 b to the non-inverting input terminal 71 of the first amplifying device 21. On the other hand, when the first switch 65 is off, signal input from the electrodes 11a and 11b to the non-inverting input terminal 71 of the first amplifying device 21 is blocked. In this embodiment, the first switch 65 is turned on.
  • a known operational amplifier can be used as the second amplifying device 22.
  • the second amplifying device 22 includes a non-inverting input terminal 76, an inverting input terminal 77, an output terminal 78, and a resistor 79.
  • the second amplifying device 22 amplifies the difference between the non-inverting input terminal 76 and the inverting input terminal 77 by a constant coefficient.
  • the second amplifying device 22 amplifies the input signal and outputs it.
  • the second amplifying device 22 amplifies the voltage generated between the pair of electrodes 11a and 11b. In the second amplifying device 22, noise is generated.
  • the voltage amplified by the second amplifying device 22 is affected by noise during amplification.
  • the second amplification device 22 is disposed in the casing 90.
  • the second amplification device 22 can operate in the normal mode and the sleep mode.
  • the second amplifying device 22 operates in either mode by switching between the normal mode and the sleep mode.
  • the current consumption in the normal mode is different from the current consumption in the sleep mode.
  • the current consumption of the second amplification device 22 in the sleep mode is smaller than the current consumption of the second amplification device 22 in the normal mode.
  • the second amplifying device 22 includes a plurality of second switches 66. When the second switch 66 is on, signals are input from the electrodes 11 a and 11 b to the non-inverting input terminal 76 of the second amplifying device 22. On the other hand, when the second switch 66 is OFF, signal input from the electrodes 11a and 11b to the non-inverting input terminal 76 of the second amplifying device 22 is blocked. In the present embodiment, the second switch 66 is turned on.
  • the current consumption of the first amplifying device 21 and the current consumption of the second amplifying device 22 are different.
  • the current consumption of the first amplifying device 21 is smaller than the current consumption of the second amplifying device 22.
  • the magnitude of the current consumption can be confirmed from the data sheets of the respective products of the first amplifying device 21 and the second amplifying device 22.
  • the noise magnitude of the first amplifying device 21 and the noise magnitude of the second amplifying device 22 are different.
  • the noise of the second amplifying device 22 is smaller than the noise of the first amplifying device 21.
  • the magnitude of the noise can be confirmed from the data sheets of the respective products of the first amplifying device 21 and the second amplifying device 22.
  • the noise of the amplifying device includes voltage noise and current noise. It is preferable that the noise of the second amplifying device 22 is smaller than the noise of the first amplifying device 21 in both voltage noise and current noise. Alternatively, it is preferable that the noise of the second amplifying device 22 is smaller than the noise of the first amplifying device 21 in at least voltage noise. When the noise of the amplification device is small, the influence of noise on the amplified voltage is relatively small.
  • the control device 50 is connected to each of the first amplifying device 21 and the second amplifying device 22.
  • the control device 50 includes an A / D conversion circuit 53, an arithmetic circuit 52, an output circuit 54, a reception circuit 55, a changeover switch 61, and a control circuit 51.
  • Each circuit and switch of the control device 50 are arranged in the casing 90.
  • the control device 50 is electrically connected to each of the operation device 63 and the output device 62.
  • the A / D conversion circuit 53 converts an analog signal into a digital signal.
  • the A / D conversion circuit 53 converts the voltage of the analog signal amplified by the first amplification device 21 or the second amplification device 22 into a digital signal.
  • the voltage digitally converted by the A / D conversion circuit 53 is transmitted from the A / D conversion circuit 53 to the arithmetic circuit 52.
  • the arithmetic circuit 52 calculates the flow rate of the fluid based on the voltage.
  • the calculation of the flow rate of fluid is Faraday's law of electromagnetic induction, namely, “When a conductor (fluid in this embodiment) moves in a magnetic field, an electromotive voltage is generated in the direction perpendicular to both the magnetic field direction and the direction of movement through the conductor. Can be implemented based on the law that "is generated and its magnitude is proportional to magnetic flux density and speed". Since the calculation method for calculating the flow rate of the fluid based on the electromotive voltage is known, detailed description thereof will be omitted. Further, the arithmetic circuit 52 can calculate the volume of the fluid that has passed through the pipe based on the calculated flow rate. The volume can be obtained by integrating the flow rate of the fluid over time.
  • the output circuit 54 outputs the flow rate and / or volume of the fluid calculated by the calculation circuit 52.
  • the output circuit 54 outputs the flow rate and / or volume to an output device 62 such as a monitor.
  • the output circuit 54 is electrically connected to the output device 62.
  • the receiving circuit 55 receives a switching command transmitted from the outside.
  • the switching command is transmitted from the outside to the receiving circuit 55 by short-range wireless communication, for example.
  • a switching command input to the operating device 63 by a user (operator) using the electromagnetic flow meter 1 is transmitted from the operating device 63 to the receiving circuit 55 by short-range wireless communication.
  • the receiving circuit 55 is wirelessly connected to the operation device 63.
  • the switching command received by the receiving circuit 55 is transmitted from the receiving circuit 55 to the control circuit 51.
  • the changeover switch 61 switches between the first amplification device 21 and the second amplification device 22.
  • a voltage is transmitted from the first amplifying device 21 to the A / D conversion circuit 53.
  • the changeover switch 61 is switched to the second amplifying device 22 side, a voltage is transmitted from the second amplifying device 22 to the A / D conversion circuit 53.
  • the control circuit 51 controls the operation of each component.
  • the control circuit 51 switches the selector switch 61 based on the switching command.
  • the control circuit 51 switches the changeover switch 61 to the first amplifying device 21 side or the second amplifying device 22 side.
  • the control circuit 51 calculates the flow rate based on the voltage amplified by the first amplifying device 21 and the voltage amplified by the second amplifying device 22 when the changeover switch 61 is switched.
  • the second mode can be switched. A user who uses the electromagnetic flow meter 1 can select the first mode and the second mode.
  • control circuit 51 switches the operation of the first amplifying device 21 from the normal mode to the sleep mode based on the received switching command.
  • control circuit 51 switches the operation of the second amplifying device 22 to the normal mode or the sleep mode.
  • the control circuit 51 switches the operation of the first amplifying device 21 and the second amplifying device 22 based on the switching command.
  • the operating device 63 can switch the mode of the electromagnetic flow meter 1 between the first mode and the second mode.
  • the operation device 63 switches between the first mode and the second mode based on a user (operator) operation. The user can select either the first mode or the second mode via the operation device 63.
  • the battery 30 for example, a known primary battery or secondary battery can be used.
  • As the primary battery for example, a known dry battery can be used.
  • the battery 30 is connected to each of the first amplifying device 21 and the second amplifying device 22.
  • the battery 30 supplies power to each of the first amplifying device 21 and the second amplifying device 22. Further, the battery 30 supplies power to the control device 50.
  • the battery 30 is disposed in the casing 90.
  • the electromagnetic flow meter 1 is a type of device in which a battery 30 is built in a casing 90.
  • the user selects whether to use the first mode or the second mode.
  • the user selects either the first mode or the second mode via the operation device 63.
  • the user can select and use either the first mode or the second mode according to the situation in which the electromagnetic flow meter 1 is used. For example, the user selects the first mode when the electromagnetic flow meter 1 is in normal use (normal use state), and selects the second mode when the electromagnetic flow meter 1 is inspected (inspection state).
  • the normal use of the electromagnetic flow meter 1 is a situation where the electromagnetic flow meter 1 is used as a water meter.
  • inspection of the electromagnetic flowmeter 1 is the condition which test
  • the user selects the first mode when the flow rate of the fluid flowing through the pipe is high, and selects the second mode when the flow rate of the fluid is low. In the present embodiment, description will be made from a state in which the first mode is used.
  • (First mode) In the first mode, when the fluid flowing in the tube 10 passes between the pair of electrodes 11a and 11b, a voltage is generated between the pair of electrodes 11a and 11b. The generated voltage is amplified by the first amplifying device 21. The voltage amplified by the first amplifier 21 is converted from an analog signal to a digital signal by the A / D conversion circuit 53. The digitally converted voltage is transmitted to the arithmetic circuit 52. The arithmetic circuit 52 calculates the flow rate of the fluid based on the received voltage. The calculated flow rate is transmitted to the output circuit 54. The output circuit 54 outputs the received fluid flow rate to the output device 62. In this way, the flow rate of the fluid flowing in the pipe 10 can be detected. Further, when the flow rate of the fluid is measured by the electromagnetic flow meter 1, the flow rate is measured over a predetermined time, and an average value of a plurality of flow rates can be obtained.
  • the first amplifying device 21 when the first mode is used, since the first amplifying device 21 is used, current consumption is small and noise is large. Further, when using the first mode, the second amplifying device 22 operates in the sleep mode. Therefore, the current consumption of the second amplifying device 22 is small.
  • the user inputs a switching command to the operation device 63.
  • the user selects the second mode via the operation device 63.
  • the switching command input to the operating device 63 is received by the receiving circuit 55.
  • the received switching command is transmitted to the control circuit 51.
  • the control circuit 51 switches the changeover switch 61 from the first amplifying device 21 side to the second amplifying device 22 side based on the received switching command.
  • the second amplifying device 22 switches the operation from the sleep mode to the normal mode based on the received switching command. As a result, the second amplifying device 22 operates in the normal mode. Further, the control circuit 51 switches the operation of the first amplifying device 21 from the normal mode to the sleep mode based on the received switching command. As a result, the first amplification device 21 operates in the sleep mode. When the second mode is used, the current consumption of the first amplifying device 21 is small because the first amplifying device 21 operates in the sleep mode.
  • the second mode when the fluid flowing in the tube 10 passes between the pair of electrodes 11a and 11b, a voltage is generated between the pair of electrodes 11a and 11b.
  • the generated voltage is amplified by the second amplifying device 22.
  • the voltage amplified by the second amplification device 22 is converted from an analog signal to a digital signal by the A / D conversion circuit 53.
  • the digitally converted voltage is transmitted to the arithmetic circuit 52.
  • the arithmetic circuit 52 calculates the flow rate of the fluid based on the received voltage.
  • the calculated flow rate is transmitted to the output circuit 54.
  • the output circuit 54 outputs the received fluid flow rate to the output device 62. In this way, the flow rate of the fluid flowing in the pipe 10 can be detected. Further, when the flow rate of the fluid is measured by the electromagnetic flow meter 1, the flow rate is measured over a predetermined time, and an average value of a plurality of flow rates can be obtained.
  • the user When using the first mode again, the user inputs a switching command to the operation device 63.
  • the user selects the first mode via the operation device 63.
  • the switching command input to the operating device 63 is received by the receiving circuit 55 and transmitted to the control circuit 51.
  • the control circuit 51 switches the changeover switch 61 from the second amplifying device 22 side to the first amplifying device 21 side based on the received switching command.
  • the control circuit 51 also switches the operation of the second amplifying device 22 from the normal mode to the sleep mode based on the received switching command. As a result, the second amplifying device 22 operates in the sleep mode.
  • the control circuit 51 switches between the first mode and the second mode based on the switching command. For example, the mode is switched to the mode selected by the user according to the usage status of the electromagnetic flow meter 1 and the flow rate of the fluid flowing through the pipe 10. Thereby, the first mode and the second mode can be used depending on the situation.
  • the current consumption of the first amplifying device 21 is smaller than the current consumption of the second amplifying device 22. Therefore, the current consumption can be suppressed by using the first mode in which the voltage is amplified by the first amplifying device 21. For example, current consumption can be suppressed by using the first mode when the electromagnetic flow meter 1 is in normal use or when the flow rate of the fluid is large. As a result, consumption of the battery 30 can be suppressed.
  • the electromagnetic flow meter 1 noise is generated in each of the first amplifying device 21 and the second amplifying device 22. Therefore, the voltage amplified by the first amplifying device 21 or the second amplifying device 22 is affected by noise. As a result, when the voltage generated over a predetermined time is amplified by the first amplifying device 21 or the second amplifying device 22, the amplified voltage varies due to the influence of noise. In addition, the fluid flow rate calculated based on the amplified voltage also varies.
  • the noise of the second amplifying device 22 is smaller than the noise of the first amplifying device 21. Therefore, in the second amplifying device 22, the magnitude of noise with respect to the voltage is relatively small.
  • the influence of noise is relatively reduced in the amplified voltage, so that the degree of relative variation is reduced. That is, the coefficient of variation in voltage variation is reduced.
  • the coefficient of variation in the variation in the flow rate of the fluid calculated based on the amplified voltage is also reduced.
  • the coefficient of variation in the variation in the flow rate of the fluid becomes small. Therefore, when the flow rate of the fluid is measured over a predetermined time and the average value of a plurality of flow rates is obtained, a reliable average value can be obtained without measuring many flow rates. As a result, a reliable average value can be obtained with a few flow rates. Therefore, a reliable flow rate can be obtained in a short time by using the second mode. For example, when the electromagnetic flow meter 1 is inspected or when the flow rate of the fluid is small, a reliable flow rate can be obtained in a short time by using the second mode.
  • the electromagnetic flow meter 1 by using the first mode and the second mode, it is possible to obtain a reliable flow rate in a short time while suppressing the consumption of the battery 30.
  • the electromagnetic flow meter 1 Since the electromagnetic flow meter 1 is generally used continuously over a long period (for example, 10 years), it is desirable that the battery 30 lasts long. Therefore, being able to suppress the consumption of the battery 30 is particularly effective for the electromagnetic flow meter 1 used for a long period of time. In addition, in the electromagnetic flow meter 1 of the type in which the battery 30 is built in, since the battery 30 is not replaced for a long period of time, it is particularly effective that the consumption of the battery 30 can be suppressed.
  • the inspection time is limited. Therefore, obtaining a reliable flow rate in a short time is particularly effective when the time is limited, such as when performing an inspection in an inspection organization.
  • noise is increased when the first mode is used, so that the influence of noise on the voltage is relatively increased when the fluid flow rate is small.
  • the coefficient of variation in voltage variation increases.
  • the coefficient of variation in the variation in the flow rate of the fluid calculated based on the voltage also increases. Therefore, when the flow rate of the fluid is measured over a predetermined time in the first mode to obtain an average value of a plurality of flow rates, many flow velocities must be measured in order to obtain a reliable average value. Therefore, it takes a long time to measure the reliable flow velocity.
  • the first mode is used during normal use of the electromagnetic flow meter 1, the flow rate is measured over a long period of time, for example, one month, so even if a long time is required to obtain a reliable flow velocity. There is no particular problem.
  • the control circuit 51 may switch between the first mode and the second mode according to the fluid flow rate. For example, based on the switching command, the control circuit 51 switches to the first mode when the flow rate of the fluid flowing through the pipe 10 is high, and switches to the second mode when the flow rate of the fluid is low. According to such a configuration, since the optimum mode can be used according to the flow rate of the fluid, a reliable flow rate can be obtained.
  • the fluid flow rate in the second mode may be smaller than the fluid flow rate in the first mode.
  • the first mode can be used when the flow rate of the fluid flowing through the pipe 10 is large, and the second mode can be used when the flow rate of the fluid is small.
  • consumption of the battery 30 can be suppressed.
  • the second mode when the flow rate of the fluid flowing in the tube 10 is small, the voltage generated between the pair of electrodes 11a and 11b is small when the fluid passes between the pair of electrodes 11a and 11b.
  • the second mode the magnitude of noise with respect to voltage can be made relatively small.
  • the operation of the second amplifying device 22 is switched from the normal mode to the sleep mode when switching from the second mode to the first mode. Since the current consumption in the sleep mode is smaller than the current consumption in the normal mode, the current consumption of the second amplifying device 22 can be suppressed by using the sleep mode. As a result, consumption of the battery 30 can be suppressed. In addition, by using the sleep mode, the power supplied from the battery 30 to the second amplifying device 22 is not cut off. Although the second amplifying device 22 may be damaged when the power is cut off, the second amplifying device 22 can be protected by continuing to supply power to the second amplifying device 22.
  • the operating device 63 can switch the state of the electromagnetic flow meter 1 between the normal use state and the inspection state.
  • the operation device 63 switches between the normal use state and the inspection state based on the operation of the user (operator). The user can select either the normal use state or the inspection state via the operation device 63.
  • a small flow inspection and a large flow inspection may be performed.
  • the flow rate of the fluid flowing through the pipe is smaller than that in the large flow inspection.
  • the flow rate of the fluid flowing through the pipe is larger than that in the small flow inspection.
  • the small flow rate inspection is an inspection state when the fluid flow rate is low
  • the large flow rate inspection is an inspection state when the fluid flow rate is large.
  • the control circuit 51 can automatically select the first mode and the second mode according to the fluid flow rate when the electromagnetic flow meter 1 is inspected (inspection state).
  • the control circuit 51 selects the first mode when the fluid flow rate is low, and selects the second mode when the fluid flow rate is high. That is, the control circuit 51 automatically selects the second mode at the time of the small flow rate inspection, and automatically selects the first mode at the time of the large flow rate inspection.
  • the user selects the normal use state via the operation device 63 during normal use.
  • a normal use state switching command is input to the operation device 63.
  • the control circuit 51 selects the first mode based on the normal use state switching command. That is, the control circuit 51 switches the mode of the electromagnetic flow meter 1 to the first mode.
  • the flow rate of the fluid is calculated based on the voltage amplified by the first amplifying device 21.
  • the user selects an inspection state via the operation device 63.
  • An inspection state switching command is input to the operation device 63.
  • the control circuit 51 automatically switches between the first mode and the second mode according to the flow rate of the fluid.
  • the control circuit 51 automatically selects the second mode when the fluid flow rate is small, that is, at the time of the small flow rate inspection.
  • the control circuit 51 automatically selects the first mode when the flow rate of the fluid is large, that is, at the time of a large flow rate inspection.
  • the inspection state when the inspection state is selected, the control circuit 51 switches between the second mode and the first mode according to the small flow rate inspection and the large flow rate inspection.
  • the flow rate of the fluid is calculated based on the voltage amplified by the second amplifying device 22.
  • the flow rate of the fluid is calculated based on the voltage amplified by the first amplifying device 21.
  • the user can select the normal use state and the inspection state.
  • the user can select a normal use state during normal use of the electromagnetic flow meter 1, and can select an inspection state during inspection of the electromagnetic flow meter 1.
  • the flow rate is measured in the first mode.
  • the inspection state is selected, the flow rate is measured in the first mode or the second mode.
  • the second mode can be used for a small flow rate inspection with a small fluid flow rate
  • the first mode can be used for a large flow rate inspection with a large fluid flow rate.
  • control circuit 51 switches from the second mode to the first mode based on the switching command received from the receiving circuit 55.
  • the present invention is not limited to this configuration.
  • the control circuit 51 has a timer function, and may switch from the second mode to the first mode when a preset time has elapsed. Thereby, it can suppress that 2nd mode is utilized over a long time. Therefore, consumption of the battery 30 can be suppressed.
  • control circuit 51 switches the operation of the second amplifying device 22 from the normal mode to the sleep mode based on the switching command received from the receiving circuit 55.
  • the configuration is limited to this configuration. It is not a thing.
  • the control circuit 51 has a timer function, and may switch from the normal mode to the sleep mode when a preset time has elapsed.
  • the second amplifying device 22 operates in the sleep mode when in the first mode.
  • the present invention is not limited to this configuration.
  • the second amplifying device 22 is turned off during the first mode and may not operate. Further, power may not be supplied to the second amplifying device 22 in the first mode.
  • the first amplifying device 21 operates in the sleep mode in the second mode.
  • the present invention is not limited to this configuration.
  • the first amplifying device 21 may operate in the normal mode without switching to the sleep mode in the second mode.
  • the voltage amplified by the first amplifying device 21 is not used when calculating the fluid flow rate.
  • the first amplifying device 21 is turned off in the second mode and may not operate. In addition, power may not be supplied to the first amplifying device 21 in the second mode.
  • the configuration of the battery 30 that supplies power to the first amplifying device 21 and the second amplifying device 22 is not particularly limited.
  • a battery that supplies power to the first amplifying device 21 and a battery that supplies power to the second amplifying device 22 may exist.
  • the battery 30 may be configured to supply power to the first amplifying device 21 and not supply power to the second amplifying device 22 in the first mode.
  • the battery 30 may be configured to supply power to the second amplifying device 22 and not supply power to the first amplifying device 21 in the second mode.
  • a signal input from the electrodes 11 a and 11 b to the first amplifying device 21 is blocked by the first switch 65 in order to protect the first amplifying device 21.
  • a signal input to the second amplifying device 22 from the electrodes 11 a and 11 b is blocked by the second switch 66 in order to protect the second amplifying device 22. It is preferable.
  • the method for comparing the noise magnitude of the first amplifying device 21 and the noise magnitude of the second amplifying device 22 is not particularly limited.
  • the magnitude of noise is confirmed by observing signals output from the first amplifying device 21 and the second amplifying device 22 in a state where no fluid is flowing between the pair of electrodes 11a and 11b. Can do.
  • signals output from the first amplifying device 21 and the second amplifying device 22 over a predetermined time are measured and compared. More specifically, signals output from each of the first amplifying device 21 and the second amplifying device 22 over a predetermined time are measured, and standard deviations ⁇ of a plurality of signals are obtained.
  • the standard deviation ⁇ 1 of the signal output from the first amplifying device 21 and the standard deviation ⁇ 2 of the signal output from the second amplifying device 22 are compared.
  • the standard deviation ⁇ of a plurality of signals is large, it can be determined that the noise is large because the variation of the plurality of signals is large.
  • the standard deviation ⁇ of the plurality of signals is small, it can be determined that the noise is small because the variation of the plurality of signals is small.
  • the magnitude of the noise can also be confirmed by the S / N ratio of the first amplifying device 21 and the S / N ratio of the second amplifying device 22.
  • the S / N ratio is a value indicating the relationship between the signal (signal) and noise (noise), and the smaller the value, the greater the noise with respect to the signal.
  • the S / N ratio of the second amplifying device 22 is larger than the S / N ratio of the first amplifying device 21.
  • the cross section of the tube 10 is circular. However, the present invention is not limited to this configuration. In other embodiments, the cross section of the tube 10 may be rectangular.
  • the insulating lining is formed on the inner surface of the tube 10, but the present invention is not limited to this configuration. For example, when the tube 10 is made of an insulating resin, it is not necessary to form an insulating lining on the inner surface of the tube 10.
  • Table 1 shows specific examples of products that can be used as the first amplification device or the second amplification device. In addition, specific examples of current consumption and noise are shown. The first amplifying device and the second amplifying device can be selected in consideration of the current consumption and the noise level.
  • Electromagnetic flow meter 10 Tube 11a: Electrode 11b: Electrode 21: First amplifying device 22: Second amplifying device 30: Battery 50: Control device 51: Control circuit 52: Arithmetic circuit 53: A / D conversion circuit 54: Output circuit 55: Reception circuit 61: Changeover switch 62: Output device 63: Operating device 65: First switch 66: Second switch 71: Non-inverting input terminal 72: Inverting input terminal 74: Output terminal 75: Resistor 76: Non-inverting Input terminal 77: Inverted input terminal 78: Output terminal 79: Resistance 90: Casing B: Magnetic field

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)

Abstract

L'invention concerne un débitmètre électromagnétique (1) qui comprend : une paire d'électrodes (11a, 11b) fixées à un tuyau (10) ; un premier dispositif d'amplification (21) pour amplifier une tension se produisant entre la paire d'électrodes (11a, 11b) ; un second dispositif d'amplification pour amplifier la tension inter-électrode, le second dispositif d'amplification (22) étant connecté aux électrodes (11a, 11b) dans une relation parallèle au premier dispositif d'amplification (21) ; et une cellule (30) pour fournir un courant électrique au premier dispositif d'amplification (21) et au second dispositif d'amplification (22). La consommation en courant électrique du premier dispositif d'amplification (21) est inférieure à la consommation en courant électrique du second dispositif d'amplification (22). Le bruit du second dispositif d'amplification (22) est inférieur au bruit du premier dispositif d'amplification (21). Un dispositif de commande (50) est configuré de manière à être apte à commuter entre un premier mode pour calculer un débit d'écoulement sur la base de la tension inter-électrode amplifiée par le premier dispositif d'amplification (21), et un second mode pour calculer un débit d'écoulement sur la base de la tension inter-électrode amplifiée par le second dispositif d'amplification (22).
PCT/JP2015/065474 2015-05-28 2015-05-28 Débitmètre électromagnétique Ceased WO2016189748A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2015/065474 WO2016189748A1 (fr) 2015-05-28 2015-05-28 Débitmètre électromagnétique

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Application Number Priority Date Filing Date Title
PCT/JP2015/065474 WO2016189748A1 (fr) 2015-05-28 2015-05-28 Débitmètre électromagnétique

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112504364A (zh) * 2019-09-13 2021-03-16 微动公司 具有噪声自适应死区时间的磁性流量计

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0214028U (fr) * 1988-07-13 1990-01-29
JPH07306069A (ja) * 1994-03-18 1995-11-21 Yokogawa Electric Corp 電磁流量計
JP2005079991A (ja) * 2003-09-01 2005-03-24 Sharp Corp 無線受信回路およびそれを備えた無線装置
WO2013153802A1 (fr) * 2012-04-12 2013-10-17 パナソニック株式会社 Capteur de mouvement et appareil électronique l'utilisant

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0214028U (fr) * 1988-07-13 1990-01-29
JPH07306069A (ja) * 1994-03-18 1995-11-21 Yokogawa Electric Corp 電磁流量計
JP2005079991A (ja) * 2003-09-01 2005-03-24 Sharp Corp 無線受信回路およびそれを備えた無線装置
WO2013153802A1 (fr) * 2012-04-12 2013-10-17 パナソニック株式会社 Capteur de mouvement et appareil électronique l'utilisant

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112504364A (zh) * 2019-09-13 2021-03-16 微动公司 具有噪声自适应死区时间的磁性流量计

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