An electronic flow meter

Abstract

The present invention discloses an electronic flowmeter, comprising: an induction device, comprising an induction coil, an impeller and a rotor; after the impeller is driven by the flowing fluid measurement object, it drives the rotor to cut the magnetic field of the induction coil to generate an induced voltage; a measurement circuit, comprising a power interface and a plurality of IGBTs; the collectors of each IGBT are connected in parallel and connected to the positive pole of the power interface; the emitters of each IGBT, which are all provided with a measuring resistor, are connected in parallel and then connected to the negative pole of the power interface through a series-connected protection resistor; the gates of each IGBT are connected in parallel and then connected to the induced voltage output end of the induction coil through a series-connected operational amplifier; a processing unit is used to generate a measurement result according to the main current of the measurement circuit. The present invention does not have the problem of stress aging of the iron sheet, thereby avoiding the failure caused by the stress aging of the iron sheet, and effectively improving the service life of the electronic flowmeter.

Description

Technical Field

[0001] The invention relates to the field of measurement, and in particular to an electronic flow meter. Background Art

[0002] When automatically controlling or real-time monitoring the transportation, storage, and processing of fluids or gases in petrochemicals, artificial gas, natural gas, and tail gas treatment, it is often necessary to measure the flow rate of the fluid or gas through a flow meter.

[0003] Common flow meters in the prior art generally include electromagnetic flow meters, turbine flow meters and volumetric flow meters, etc. 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, the signal detection methods include inductive, photoelectric, and reed switch types, etc., which use mechanical actions to control the on and off of the circuit to transmit current.

[0004] After research, the inventor found that the prior art has at least the following defects:

[0005] The above-mentioned flow meters all have the problem of mechanical aging. For example, the magnetism of the permanent magnet in the induction type will naturally fade, while the mechanical action of the iron sheet inside the reed switch is attracted by magnetic force, which is prone to stress aging during use, leading to failures such as inadequate attraction or disconnection, or even damage. Therefore, the service life of the flow meter in the prior art is too short. Summary of the invention

[0006] The main purpose of the present invention is to reduce the failure probability of the flow meter and increase the service life of the flow meter.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] The invention discloses an electronic flow meter, comprising:

[0009] The induction device comprises an induction coil, an impeller and a rotor; the impeller is driven by a flowing gaseous or liquid measurement object to drive the rotor to cut the magnetic field of the induction coil to generate an induced voltage;

[0010] The measuring circuit comprises a power interface and a plurality of insulated gate bipolar transistors (IGBTs); the collectors of the IGBTs are connected in parallel and then connected to the positive electrode of the power interface; the emitters of the IGBTs, each of which is provided with a measuring resistor, are connected in parallel and then connected to the negative electrode of the power interface via a series-connected protection resistor; the gates of the IGBTs are connected in parallel and then connected to the induced voltage output end of the induction coil via a series-connected operational amplifier;

[0011] A processing unit is provided for generating a measurement result based on the mains current of the measurement circuit.

[0012] Preferably, in the present invention, the measurement object includes a gaseous measurement object and / or a liquid measurement object.

[0013] Preferably, in the present invention, the gaseous state measurement includes natural gas, artificial coal gas, natural gas or tail gas.

[0014] Preferably, in the present invention, the liquid measurement object includes petroleum or liquefied gas.

[0015] Preferably, in the present invention, the number of the measuring resistors is 4 to 15.

[0016] Preferably, in the present invention, the voltage of the power interface is a DC voltage of 15V to 36V.

[0017] Preferably, in the present invention, the IGBT comprises an NPN junction type.

[0018] Preferably, in the present invention, the main circuit current of the measurement circuit includes:

[0019] The current at the negative terminal of the power interface.

[0020] Preferably, in the present invention, the electronic flow meter is used for measuring fluid flow in a pipeline.

[0021] Preferably, in the present invention, the processing unit is used for:

[0022] Obtaining a current value of a main circuit current in the measurement circuit;

[0023] Calculating a current resistance value in the measurement circuit according to the current value;

[0024] Determine the number of IGBTs currently in the on state according to the current resistance value;

[0025] Calculating the current voltage value of the induced voltage output by the induction coil according to the corresponding relationship between the number of IGBTs in the on state and the voltage value of the induced voltage output by the induction coil;

[0026] determining a current impeller speed according to the current voltage value;

[0027] The flow rate of the measured object is calculated according to the current impeller speed.

[0028] Beneficial Effects

[0029] The electronic flow meter in the present invention includes a sensing device, a measuring circuit and a processing unit, wherein the sensing device is provided with an impeller, a rotor and an induction coil, and the impeller can drive the rotor to rotate under the drive of the fluid measurement object, thereby causing the induction coil to output an induced voltage; different flow velocities of the fluid measurement object can drive the rotor to rotate at different speeds, thereby causing the induction coil to output induced voltages of different voltage values; then, the measuring circuit in the present invention includes a plurality of IGBTs, and a corresponding number of IGBTs can be stimulated to conduct according to the induced voltages of different voltage values; and the different number of IGBTs turned on will make the overall resistance of the measuring circuit different, thereby causing the current value of the main current of the measuring circuit to change accordingly; in this way, by real-time acquisition of the current value of the main current of the measuring circuit, the rotation speed of the impeller can be reversely calculated, thereby calculating the flow rate of the fluid measurement object.

[0030] From the above, it can be seen that the electronic flow meter in the present invention does not require the iron sheet to mechanically move under the action of magnetic force to measure the flow of the measured object, so there is no problem of stress aging of the iron sheet, and thus the occurrence of failures such as inadequate attraction or disconnection due to stress aging of the iron sheet is avoided, thereby effectively improving the service life of the electronic flow meter.

[0031] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of 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 paying any creative work.

[0033] Figure 1 It is a schematic diagram of the structure of the electronic flow meter described in the present invention. DETAILED DESCRIPTION

[0034] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0035] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0036] In this document, for the convenience of description, spatial relative terms such as "below", "below", "down", "above", "above", "upper", etc. may be used to describe the relationship between one element or feature and another element or feature in the accompanying drawings. It should be understood that the spatial relative terms are intended to include different directions of objects in use or operation in addition to the directions drawn in the drawings. For example, if the object in the figure is turned over, the elements described as being "below" or "below" other elements or features will be oriented "above" the elements or features. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used in this document should be interpreted accordingly.

[0037] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable.

[0038] In order to reduce the failure rate of the flow meter and increase its service life, please refer to Figure 1 , an embodiment of the present invention provides an electronic flow meter, including a sensing device 01, a measuring circuit 02 and a processing unit 03, wherein:

[0039] The induction device 01 includes an induction coil 11, an impeller 12 and a rotor 13; the impeller 12 is driven by the flowing fluid measurement object to drive the rotor 13 to cut the magnetic field of the induction coil 11 to generate an induced voltage;

[0040] The measuring circuit 02 includes a power interface 21 and a plurality of insulated gate bipolar transistors IGBT22; the collectors of the IGBT22 are connected in parallel and then connected to the positive electrode of the power interface 21; the emitters of the IGBT22, each of which is provided with a measuring resistor 23, are connected in parallel and then connected to the negative electrode of the power interface 21 through a series-connected protection resistor 24; the gates of the IGBT22 are connected in parallel and then connected to the induced voltage output end of the induction coil 11 through a series-connected operational amplifier 25;

[0041] The processing unit 03 is used to generate a measurement result according to the main circuit current of the measurement circuit 02 .

[0042] In practical applications, the individual resistance values ​​and the number of the measuring resistors 23 in the embodiment of the present invention can be set accordingly according to different requirements for accuracy or different ranges; specifically, the smaller the resistance value of a single measuring resistor 23, the higher the measurement accuracy, and the more the number of measuring resistors 23, the larger the measurement range. Therefore, the individual resistance values ​​and the number of measuring resistors 23 used in the embodiment of the present invention can be set by technicians in this field according to different requirements for accuracy and range, and no specific limitation is made here. Generally, the number of measuring resistors 23 can be set to 4 to 15.

[0043] like Figure 1 As shown, taking the number of measuring resistors 23 as 4 as an example, the working principle of the embodiment of the present invention is described:

[0044] The electronic flow meter in the embodiment of the present invention is typically used for flow measurement of a fluid measurement object in a pipeline; specifically, the fluid measurement object can be gaseous or liquid, for example, it can be natural gas, artificial coal gas, natural gas or exhaust gas, as well as petroleum or liquefied gas, etc.

[0045] The sensing device 01 in the embodiment of the present invention is to be placed in a fluid measurement object (e.g., in a natural gas pipeline), and its impeller 11 can drive the rotor 12 to rotate under the drive of the fluid measurement object, thereby causing the induction coil 13 to output an induced voltage; different flow rates of the fluid measurement object can drive the rotor 12 to rotate at 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.

[0046] The four IGBTs 22 (named G1 to G4 respectively) in the measurement circuit 02 may be of NPN junction type, and a measurement resistor 23 (named R1 to R4 respectively) is connected in series to the emitters of the four IGBTs 22 respectively; the measurement circuit 02 includes a power interface 21 to access the power supply (the voltage value of the power supply may be a DC power supply of 15V to 36V), wherein the positive electrode of the power interface 21 is connected in parallel to the emitters of each IGBT 22 respectively; 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, and finally the negative electrode of the power interface 21 is connected to the other end of the protection resistor 24; in the embodiment of the present invention, by providing the protection resistor 24 (R5), the failure of the measurement circuit 02 due to a short circuit can be avoided.

[0047] In order to activate the conduction of different numbers of IGBTs 22 according to different voltage values, in the embodiment of the present invention, the gates of the various IGBTs 22 are first connected in parallel, and then connected in series with the operational amplifier 25 and connected to the induction voltage output terminal of the induction coil 11; thus, as the speed of the rotor 13 (or the impeller 12) is different, the voltage value of each gate of the IGBTs 22 connected to the measurement circuit 02 is also different. When the speed of the impeller 12 is increased, the voltage value of the gate of the IGBTs 22 will also increase accordingly, so that the number of IGBTs 22 turned on in the measurement circuit 02 will also increase;

[0048] As the number of IGBTs 22 turned on in the measurement circuit 02 changes, the resistance of the measurement circuit 02 changes. The greater the number of IGBTs 22 turned on, the smaller the overall resistance of the measurement circuit 02 will be, thereby increasing the current value of the main circuit current of the measurement circuit 02 accordingly.

[0049] Based on the above cognition, the embodiment of the present invention collects the current value of the main current of the measurement circuit 02 in real time, and then derives the current speed of the impeller 12, and then can finally calculate the flow rate of the fluid measurement object. In practical applications, the main current of the measurement circuit 02 includes the current at the negative end of the power interface 21.

[0050] In practical applications, the processing unit for calculating the flow rate of the fluid measurement object by measuring the main current value of the circuit 02 may include the following specific working procedures:

[0051] S11, obtaining the current value of the main current in the measurement circuit 02;

[0052] S12, calculating the current resistance value in the measurement circuit according to the current value;

[0053] S13, determining the number of IGBTs 22 currently in the on state according to the current resistance value;

[0054] S14, calculating 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 on state and the voltage value of the induced voltage output by the induction coil 11;

[0055] S15, determining the current speed of the impeller 12 according to the current voltage value;

[0056] S16, calculating the flow rate of the fluid measurement object according to the current rotation speed of the impeller 12.

[0057] The number of conducting IGBT22s is the same as the number of main resistors connected in parallel to the circuit. Specifically, let the input voltage of the power supply interface 21 be U. When the rotational speed of the impeller 12 is relatively low, the induced voltage generated by cutting the induction coil 11 can only make G1 conduct after amplification. At this time, the voltage is not sufficient to make G2 - G4 conduct. At this time, the trunk current is I1 = U / (R1 + R5), and the trunk current is the smallest at this time. As the rotational speed of the impeller 12 increases and the induced voltage increases, on the basis of G1 conduction, G2 conducts; G3 and G4 still remain cut-off. At this time, R1 and R2 form a parallel resistance relationship, and the resistance value is: 1 / (1 / R1 + 1 / R2) < R1. Therefore, the trunk current I2 > I1; further, as the rotational speed of the impeller continues to increase, the output voltage of the operational amplifier continues to rise. When G3 conducts, R3 is incorporated into the working circuit. At this time, G1, G2, and G3 conduct. According to the circuit principle, the total parallel resistance continues to decrease, and the trunk current continues to increase; finally, as the rotational speed of the impeller 12 continues to increase, the output voltage makes G4 conduct. At this time, all 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 fluid measurement object in the pipeline is the highest at this time.

[0058] In practical applications, to ensure safety, the main voltage source connected to the power supply interface 21 can select a DC voltage of 15 - 36V. The gate input voltage of IGBT22 can be controlled by controlling the number of turns of the induction coil and the amplification ratio of the operational amplifier. IGBTs with different gate conduction voltages can be selected, such as 1V, 2V, 3V, 4V, to ensure the sequential conduction of IGBTs. Since the resistance components and IGBT components have low cost, small volume, and light weight, the electronic flowmeter in the embodiment of the present invention also has the advantages of low cost and small volume.

[0059] In summary, the electronic flowmeter in the present invention includes an induction device, a measurement circuit, and a processing unit. The induction device is provided with an impeller, a rotor, and an induction coil. The impeller can drive the rotor to rotate under the drive of the fluid measurement object, thereby enabling the induction coil to output an induced voltage; different flow rates of the fluid measurement object can drive the rotor at different rotational speeds, thereby enabling the induction coil to output induced voltages with different voltage values; then, the measurement circuit in the present invention includes multiple IGBTs. According to the induced voltages with different voltage values, the corresponding number of IGBTs can be excited to conduct; and the different numbers of conducting IGBTs will cause the overall resistance of the measurement circuit to be different, thereby causing the current value of the trunk current of the measurement circuit to change accordingly; in this way, by collecting the current value of the trunk current of the measurement circuit in real time, the rotational speed of the impeller can be inversely calculated, and then the flow rate of the fluid measurement object can be calculated.

[0060] From the above, it can be seen that the electronic flow meter in the present invention does not require the iron sheet to mechanically move under the action of magnetic force to measure the flow of the measured object, so there is no problem of stress aging of the iron sheet, and thus the occurrence of failures such as inadequate attraction or disconnection due to stress aging of the iron sheet is avoided, thereby effectively improving the service life of the electronic flow meter.

[0061] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. Any simple modifications, equivalent changes and modifications made to the above exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. An electronic flow meter, characterized in that: include: The induction device comprises an induction coil, an impeller and a rotor; the impeller is driven by the flowing fluid measurement object to drive the rotor to cut the magnetic field of the induction coil to generate an induced voltage; The measuring circuit comprises a power interface and a plurality of insulated gate bipolar transistors (IGBTs); the collectors of the IGBTs are connected in parallel and then connected to the positive electrode of the power interface; the emitters of the IGBTs, each of which is provided with a measuring resistor, are connected in parallel and then connected to the negative electrode of the power interface via a series-connected protection resistor; the gates of the IGBTs are connected in parallel and then connected to the induced voltage output end of the induction coil via a series-connected operational amplifier; A processing unit is used to generate a measurement result according to the main circuit current of the measurement circuit.

2. The electronic flow meter according to claim 1, characterized in that: The fluid measurement object includes a gaseous measurement object and / or a liquid measurement object.

3. The electronic flow meter according to claim 2, characterized in that: The gaseous state measurement includes artificial gas, natural gas or tail gas.

4. The electronic flow meter according to claim 2, characterized in that: The liquid measurement object includes petroleum or liquefied gas.

5. The electronic flow meter according to claim 1, characterized in that: The number of the measuring resistors is comprised between 4 and 15.

6. The electronic flow meter according to claim 1, characterized in that: The voltage of the power supply interface is a DC voltage of 15V to 36V.

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

8. 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.

9. The electronic flow meter according to claim 1, characterized in that: The electronic flow meter is used for measuring the flow rate of a fluid measurement object in a pipeline.

10. The electronic flow meter according to claim 9, characterized in that: The processing unit is used for: Obtaining a current value of a main circuit current in the measurement circuit; Calculating a current resistance value in the measurement circuit according to the current value; Determine the number of IGBTs currently in the on state according to the current resistance value; Calculating the current voltage value of the induced voltage output by the induction coil according to the corresponding relationship between the number of IGBTs in the on state and the voltage value of the induced voltage output by the induction coil; determining a current impeller speed according to the current voltage value; The flow rate of the fluid measurement object is calculated according to the current impeller speed.

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