An electronic flowmeter

Abstract

The application discloses an electronic flowmeter, which comprises an inductive device and a measuring circuit; the inductive device comprises an inductive coil, an impeller and a rotor connected with the impeller; the measuring circuit comprises a power supply interface, a plurality of insulated gate bipolar transistors (IGBT); the collectors of the IGBTs are connected in parallel and then connected with the positive pole of the power supply interface; the emitters of the IGBTs, which are all provided with measuring resistors, are connected in parallel and then connected with the negative pole of the power supply interface through a series-connected protection resistor; the gates of the IGBTs are connected in parallel and then connected with the inductive voltage output end of the inductive coil through a series-connected operational amplifier. The application can avoid the faults caused by the stress aging of the iron sheet, such as the attraction or disconnection not in place, and effectively prolongs the service life of the electronic flowmeter. In addition, the small-range fluctuation of the inductive voltage generated by the inductive device will not cause the instability of the measurement result, and the stability of the measurement result can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of measurement, and particularly to an electronic flow meter. Background Technology

[0002] When performing automatic control or real-time monitoring of processes such as the transportation, storage, and treatment of fluids or gases, such as petrochemicals, manufactured gas, natural gas, and exhaust gas treatment, it is often necessary to measure the flow rate of the fluids or gases using flow meters.

[0003] In the existing technology, general flow meters generally include electromagnetic flow meters, turbine flow meters, and volumetric flow meters. These types of flow meters all use different mechanical means to detect flow information signals and convert them into electrical signals for remote transmission. Among them, signal detection methods include inductive, photoelectric, and reed switch mechanical actions to control the on and off of the circuit to transmit current.

[0004] The inventors discovered through research that the existing technology has at least the following defects: All of the above-mentioned flow meters suffer from mechanical aging problems. For example, the mechanical action of the iron plate inside the reed switch relying on magnetic attraction is prone to stress aging during use, which can lead to malfunctions such as incomplete engagement or disengagement, or even damage. Therefore, the service life of flow meters in the existing technology is too short.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The main objective of this invention is to reduce the failure rate of flow meters and improve their service life.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention discloses an electronic flow meter, including a sensing device and a measuring circuit; The sensing device includes an induction coil, an impeller, and a rotor connected to the impeller; The measurement circuit includes a power interface and multiple insulated gate bipolar transistors (IGBTs). The collectors of each IGBT are connected in parallel and then connected to the positive terminal of the power interface. The emitters of each IGBT, which are equipped with measuring resistors, are connected in parallel and then connected to the negative terminal of the power interface through a series protection resistor. The gates of each IGBT are connected in parallel and then connected to the induced voltage output terminal of the induction coil through a series operational amplifier.

[0008] Preferably, in this invention, it further includes: An information acquisition unit is used to obtain the real-time current value of the main circuit of the measurement circuit; the real-time current value is used to generate measurement results according to a preset algorithm.

[0009] Preferably, in this invention, it further includes: Each IGBT emitter is connected in series with an indicator light.

[0010] Preferably, in this invention, the measurement object includes a gaseous measurement object or a liquid measurement object.

[0011] Preferably, in this invention, the gaseous measurement includes natural gas, manufactured gas, natural gas, or tail gas.

[0012] Preferably, in this invention, the liquid measurement object includes petroleum or liquefied gas.

[0013] Preferably, in this invention, the number of IGBTs includes 4 to 15.

[0014] Preferably, in this invention, the voltage of the power interface is a DC voltage of 15V to 36V.

[0015] Preferably, in this invention, the IGBT includes an NPN junction.

[0016] Preferably, in this invention, the main circuit current of the measuring circuit includes: The current at the negative terminal of the power interface.

[0017] Preferably, in this invention, a buffer resistor is also provided between the emitter and collector of the IGBT.

[0018] Preferably, in this invention, the electronic flow meter is used for flow measurement of the object being measured inside the pipeline.

[0019] Beneficial effects The electronic flow meter of this invention includes a sensing device and a measuring circuit. The sensing device comprises an impeller, a rotor, and an induction coil. The impeller can drive the rotor to rotate under the influence of the measured object (i.e., the fluid or gas to be measured), thereby causing the induction coil to output an induced voltage. Different flow velocities of the measured object can drive the rotor to rotate at different speeds, thereby causing the induction coil to output induced voltages of different values. Next, the measuring circuit of this invention includes multiple IGBTs. According to different induced voltage values, a corresponding number of IGBTs can be activated. The different number of IGBTs activated will cause different overall resistances of the measuring circuit, thereby causing corresponding changes in the current value of the main circuit of the measuring circuit. In this way, by acquiring the current value of the main circuit of the measuring circuit in real time, the rotational speed of the impeller can be calculated, and then the flow rate of the measured object can be calculated.

[0020] As can be seen from the above, on the one hand, the electronic flow meter of the present invention does not require the iron sheet to mechanically measure the flow of the object under the action of magnetic force, so there is no problem of stress aging of the iron sheet, and thus avoids failures such as incomplete engagement or disengagement caused by stress aging of the iron sheet, effectively improving the service life of the electronic flow meter.

[0021] On the other hand, in this invention, the final measurement result is generated by measuring the current value corresponding to different numbers of IGBTs in the on state. Therefore, the small fluctuations in the induced voltage generated by the sensing device will not cause instability in the measurement result, thereby effectively improving the stability of the measurement result.

[0022] Furthermore, to prevent abnormal conduction of the IGBTs due to residual charge, which could affect the normal measurement accuracy of the electronic flowmeter, this invention also includes a buffer resistor for each IGBT. During the IGBT turn-off process, the residual charge of the capacitive element and the buffer resistor form a circuit to dissipate the residual energy of the element, thereby preventing abnormal conduction caused by residual charge. This effectively improves the accuracy of the electronic flowmeter and reduces its failure rate.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the electronic flow meter described in this invention; Figure 2 This is a schematic diagram of the structure of the buffer resistor described in this invention. Detailed Implementation

[0026] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0027] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0028] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “up,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0029] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0030] To reduce the likelihood of flow meter failure and extend its service life, refer to Figure 1 This invention provides an electronic flow meter, including a sensing device 01 and a measuring circuit 02, wherein: The sensing device 01 includes an induction coil 11, an impeller 12, and a rotor 13; the impeller 12, driven by the flowing measuring object, drives the rotor 13 to cut the magnetic field of the induction coil 11 to generate an induced voltage. The measurement circuit 02 includes a power interface 21 and multiple IGBTs 22; the collectors of each IGBT 22 are connected in parallel and then connected to the positive terminal of the power interface 21; the emitters of each IGBT 22, each equipped with a measuring resistor 23, are connected in parallel and then connected to the negative terminal of the power interface 21 through a series-connected protection resistor 24; the gates of each IGBT 22 are connected in parallel and then connected to the induced voltage output terminal of the induction coil 11 through a series-connected operational amplifier 25. In practical applications, depending on the required precision or measurement range, the number of IGBTs 22 and the individual resistance values ​​of the measuring resistors 23 in this embodiment of the invention can be set by those skilled in the art without specific limitations. Specifically, the smaller the resistance value of a single measuring resistor 23, the higher the measurement precision, and the more IGBTs 22 there are, the larger the measurement range. Therefore, the individual resistance values ​​of the measuring resistors 23 and the number of IGBTs 22 used in this embodiment of the invention can be set by those skilled in the art according to different requirements for precision and measurement range, without specific limitations. Generally, the number of IGBTs 22 can be set to 4 to 15.

[0031] like Figure 1 As shown, taking an example with four IGBT22 units (G1 to G4), the working principle of this embodiment of the invention will be explained: The electronic flow meter in this embodiment of the invention is typically used for flow measurement of objects within pipelines. Specifically, the object being measured can be gaseous or liquid, such as natural gas, manufactured gas, natural gas or tail gas, as well as petroleum or liquefied petroleum gas.

[0032] In this embodiment of the invention, the sensing device 01 is placed inside the object being measured (e.g., inside a natural gas pipeline). Its impeller 11 can drive the rotor 12 to rotate under the drive of the object being measured, thereby causing the induction coil 13 to output an induced voltage. Different flow rates of the fluid being measured can drive the rotor 12 to different speeds. Specifically, when the fluid measurement flow rate is fast, the speed of the driven rotor 12 is also faster, thereby causing the voltage value of the induced voltage output by the induction coil 13 to increase accordingly.

[0033] In practical applications, to ensure safety, the main voltage source connected to power interface 21 can be a 15-36V DC voltage. The gate input voltage of IGBT 22 can be controlled by adjusting the number of turns of the induction coil and the amplification ratio of the operational amplifier. IGBTs with different gate turn-on voltages, such as 1V, 2V, 3V, and 4V, can be selected to ensure sequential conduction of the IGBTs. Because the resistors and IGBT components are inexpensive, small in size, and lightweight, the electronic flowmeter in this embodiment of the invention also has the advantages of low cost and small size.

[0034] In order to activate different numbers of IGBT22s based on different voltage values, in this embodiment of the invention, the gates of each IGBT22 are first connected in parallel, and then connected in series with the operational amplifier 25 and then connected to the induced voltage output terminal of the induction coil 11. In this way, as the speed of the rotor 13 (or impeller 12) is different, the voltage value of each gate of the IGBT22 connected to the measurement circuit 02 is also different. When the speed of the impeller 12 increases, the voltage value of the IGBT22 gate will also increase accordingly, so the number of IGBT22s turned on in the measurement circuit 02 will also be more. As the number of IGBTs 22 that are turned on in the measurement circuit 02 varies, the resistance of the measurement circuit 02 will change. The more IGBTs 22 that are turned on, the lower the overall resistance of the measurement circuit 02 will be, which in turn will increase the current value of the main circuit of the measurement circuit 02. In this way, by acquiring the current value of the main circuit of the measurement circuit in real time, the impeller speed can be calculated, and then the flow rate of the measured object can be calculated.

[0035] The four IGBTs 22 in the measurement circuit 02 (named G1 to G4 respectively) can be NPN junction type. A measurement resistor 23 (named R1 to R4 respectively) is connected in series with the emitter of each of the four IGBTs 22. The measurement circuit 02 includes a power interface 21 for power supply (the voltage of the power supply can be a DC power supply of 15V to 36V). The positive terminal of the power interface 21 is connected in parallel with the emitter of each IGBT 22. The emitters of each IGBT 22 connected in series with the measurement resistor 23 are connected in parallel together, and then a protection resistor 24 is connected in series. Finally, the negative terminal of the power interface 21 is connected to the other end of the protection resistor 24. In this embodiment of the invention, by providing the protection resistor 24 (R5), the measurement circuit 02 can be prevented from failing due to short circuit.

[0036] In the embodiment of the present invention, the number of IGBTs 22 turned on in the measurement circuit 02 is the same as the number of measurement resistors 23 connected in parallel to the circuit. Specifically, assuming that the access voltage of the power supply interface 21 is U, when the rotation speed of the impeller 12 is relatively low, the induced voltage generated by cutting the induction coil 11 can only make G1 turn on after amplification. At this time, the voltage is not enough to make G2-G4 turn on. At this time, the trunk current is I1 = U / (R1 + R5), and the trunk current is the smallest at this time. As the rotation speed of the impeller 12 increases, the induced voltage increases. On the basis of G1 being turned on, G2 is turned on; G3 and G4 still remain cut off. At this time, R1 and R2 form a parallel resistance, and the resistance value is: 1 / (1 / R1 + 1 / R2) < R1. Therefore, the trunk current I2 > I1; further, as the rotation speed of the impeller continues to increase, the output voltage of the operational amplifier continues to rise. When G3 is turned on, R3 is incorporated into the working circuit. At this time, G1, G2, and G3 are turned on. According to the circuit principle, the total parallel resistance continues to decrease, and the trunk current continues to increase; finally, as the rotation speed of the impeller 12 continues to increase, the output voltage makes G4 turn on. At this time, all the resistors are incorporated into the working circuit. At this time, the total resistance of the measurement circuit 02 is the smallest, and the trunk output current is the largest. At the same time, it also means that the flow rate of the measurement object in the pipeline is the highest at this time.

[0037] Furthermore, according to different application requirements, in the embodiment of the present invention, different measurement result generation schemes may also be included. Specifically: On the one hand, when the electronic flowmeter in the embodiment of the present invention is used for remote data acquisition and processing, in the embodiment of the present invention, an information acquisition unit for obtaining the real-time current value of the trunk of the measurement circuit may also be provided. In this way, the remote data processing center can use the real-time current value as an input and generate a final measurement result according to a preset algorithm.

[0038] Its specific working process may include: S11. Obtain the current value of the trunk current in the measurement circuit 02; S12. Calculate the current resistance value in the measurement circuit according to the current value; S13. Determine the number of IGBTs 22 in the conduction state according to the current resistance value; S14. Calculate the current voltage value of the induced voltage output by the induction coil 11 according to the corresponding relationship between the number of IGBTs 22 in the conduction state and the voltage value of the induced voltage output by the induction coil 11; S15. Determine the current rotation speed of the impeller 12 according to the current voltage value; S16. Calculate the flow rate of the measurement object according to the current rotation speed of the impeller 12.

[0039] On the other hand, in the embodiment of the present invention, indicator lights may also be connected in series to the emitters of each IGBT.

[0040] In this way, different numbers of IGBT22s are activated based on different voltage values, and the number of indicator lights also changes accordingly. Thus, without the need for additional processing units, the corresponding measurement results can be obtained intuitively.

[0041] The inventors further discovered that the IGBT22 is a capacitive device, and there is a discharge process during its brief turn-off. When a large current flows through it, there will be an incomplete discharge state. Then, the residual charge left by the incomplete discharge has a certain possibility of causing abnormal conduction between the collector and emitter.

[0042] For example, the abnormal conduction described above is further reflected in the flow meter's condition as follows: During the process of decreasing flow in the measured pipeline, G3 conducts and correctly displays the flow reading. However, as the flow continues to decrease, the residual charge accumulated during the conduction of G3 will cause G3 to remain on, and the external reading of the flowmeter will remain at the reading displayed when G3 was on. Therefore, it cannot reflect the reading at lower flow rates. This causes a delay in the measurement result, which in practical applications will lead to a lag in the action of related chain reactions, and consequently, will distort the reading of the electronic flowmeter, making it unable to quickly and accurately reflect changes in flow.

[0043] To solve the above problems, such as Figure 2 As shown, in this embodiment of the invention, a buffer resistor 31 may also be provided between the emitter and collector of the IGBT22.

[0044] Specifically, in this embodiment of the invention, the two ends of the RC buffer resistor 31 are connected to the emitter and collector circuits of the IGBT 22, respectively.

[0045] In this embodiment of the invention, by providing a buffer circuit, after the IGBT22 is turned off, the capacitive IGBT22 will form an RC circuit with the buffer resistor 31, thereby effectively releasing the residual charge and consuming it in the RC circuit. The IGBT that is mistakenly turned on will turn off naturally. At the same time, the buffer resistor 31 can also accelerate the release rate of charge during the turn-off process, thereby solving the problem of mistaken turn-on fault caused by residual charge and improving the response time of the measurement result.

[0046] As can be seen from the above, the electronic flow meter of the present invention does not require the iron sheet to mechanically measure the flow of the object under the action of magnetic force, so there is no problem of stress aging of the iron sheet, and thus avoids failures such as incomplete engagement or disengagement caused by stress aging of the iron sheet, effectively improving the service life of the electronic flow meter.

[0047] In practical applications, the resistance value of the buffer resistor 31 can be set within the following range: The buffer resistor is equivalent to a zero-input state response. Under normal circumstances, the time constant needs to meet the purpose of rapid charge consumption. The time constant can be set to t=0.01. The equivalent capacitance between the collector and emitter of the IGBT is mostly between 0.1uF and 10uF. The selected buffer resistor should meet the limitations of capacitance and time constant. The formula is t=RC. Therefore, the resistance value of the buffer resistor is between 10KΩ and 100KΩ.

[0048] In summary, the electronic flow meter in this embodiment of the invention includes a sensing device, a measuring circuit, and a processing unit. The sensing device comprises an impeller, a rotor, and an induction coil. The impeller can drive the rotor to rotate under the influence of the measured object, thereby causing the induction coil to output an induced voltage. Different flow velocities of the measured object can drive the rotor to rotate at different speeds, thereby causing the induction coil to output induced voltages of different values. Next, the measuring circuit in this invention includes multiple IGBTs. According to different induced voltage values, a corresponding number of IGBTs can be activated. The different number of IGBTs activated will cause different overall resistances of the measuring circuit, thereby causing corresponding changes in the current value of the main circuit current of the measuring circuit. In this way, by acquiring the current value of the main circuit current in real time, the rotational speed of the impeller can be calculated, and then the flow rate of the measured object can be calculated.

[0049] As can be seen from the above, on the one hand, the electronic flow meter of the present invention does not require the iron sheet to mechanically measure the flow of the object under the action of magnetic force, so there is no problem of stress aging of the iron sheet, and thus avoids failures such as incomplete engagement or disengagement caused by stress aging of the iron sheet, effectively improving the service life of the electronic flow meter.

[0050] On the other hand, in this invention, the final measurement result is generated by measuring the current value corresponding to different numbers of IGBTs in the on state. Therefore, the small fluctuations in the induced voltage generated by the sensing device will not cause instability in the measurement result, thereby effectively improving the stability of the measurement result.

[0051] Furthermore, to prevent abnormal conduction of the IGBTs due to residual charge, which could affect the normal measurement accuracy of the electronic flowmeter, this invention also includes a buffer resistor for each IGBT. During the IGBT turn-off process, the residual charge of the capacitive element and the buffer resistor form a circuit to dissipate the residual energy of the element, thereby preventing abnormal conduction caused by residual charge. This effectively improves the accuracy of the electronic flowmeter and reduces its failure rate.

[0052] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. An electronic flow meter, characterized in that, Includes sensing devices and measuring circuits; The sensing device includes an induction coil, an impeller, and a rotor connected to the impeller; The measurement circuit includes a power interface and multiple insulated gate bipolar transistors (IGBTs). The collectors of each IGBT are connected in parallel and then connected to the positive terminal of the power interface. The emitters of each IGBT, which are equipped with measuring resistors, are connected in parallel and then connected to the negative terminal of the power interface through a series protection resistor. The gates of each IGBT are connected in parallel and then connected to the induced voltage output terminal of the induction coil through a series operational amplifier. An information acquisition unit is used to obtain the real-time current value of the main circuit of the measurement circuit; the real-time current value is used to generate measurement results according to a preset algorithm.

2. The electronic flow meter according to claim 1, characterized in that, Also includes: Each IGBT emitter is connected in series with an indicator light.

3. The electronic flow meter according to claim 2, characterized in that, The objects being measured can be either gaseous or liquid.

4. The electronic flow meter according to claim 3, characterized in that, The gaseous measurement objects include natural gas, manufactured gas, or exhaust gas.

5. The electronic flow meter according to claim 3, characterized in that, The liquid measurement object includes petroleum or liquefied gas.

6. The electronic flow meter according to claim 1, characterized in that, The number of IGBTs ranges from 4 to 15.

7. The electronic flow meter according to claim 1, characterized in that, The power interface has a DC voltage of 15V to 36V.

8. The electronic flow meter according to claim 1, characterized in that, The IGBT includes an NPN junction.

9. The electronic flow meter according to claim 1, characterized in that, The main circuit current of the measuring circuit includes: The current at the negative terminal of the power interface.

10. The electronic flow meter according to claim 1, characterized in that, A buffer resistor is also provided between the emitter and collector of the IGBT.

11. The electronic flow meter according to claim 1, characterized in that, The electronic flow meter is used for flow measurement of objects within a pipeline.

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