CN221006426U - Explosion-proof electromagnetic flow measuring circuit - Google Patents
Explosion-proof electromagnetic flow measuring circuit Download PDFInfo
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- CN221006426U CN221006426U CN202323206005.3U CN202323206005U CN221006426U CN 221006426 U CN221006426 U CN 221006426U CN 202323206005 U CN202323206005 U CN 202323206005U CN 221006426 U CN221006426 U CN 221006426U
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- 238000012360 testing method Methods 0.000 claims abstract description 58
- 238000004804 winding Methods 0.000 claims abstract description 27
- 238000005259 measurement Methods 0.000 claims abstract description 23
- 238000006243 chemical reaction Methods 0.000 claims description 19
- 230000003993 interaction Effects 0.000 claims description 17
- 230000005284 excitation Effects 0.000 claims description 16
- 238000001514 detection method Methods 0.000 abstract description 10
- 239000012530 fluid Substances 0.000 description 15
- 238000004880 explosion Methods 0.000 description 9
- 230000005540 biological transmission Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010892 electric spark Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
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Abstract
The application relates to the technical field of electromagnetic flow measurement circuits, and particularly discloses an explosion-proof electromagnetic flow measurement circuit. The explosion-proof electromagnetic flow measuring circuit comprises a pair of test electrodes, a pair of windings, a first current limiting resistor, a second current limiting resistor, a converter, a zener diode and a fuse. One of the test electrodes is connected in series with a first current limiting resistor, and the other test electrode is connected in series with a second current limiting resistor. The first current limiting resistor, the second current limiting resistor and the pair of windings are all connected to the signal receiving end of the converter. The power connection end of the converter is connected to two ends of the zener diode. The fuse is connected to the power connection terminal of the converter and one end of the zener diode. The zener diode is arranged at one end of the converter far away from the test electrode, so that the converter can directly receive an electric signal sent by the test electrode, and the electric signal is not easy to be interfered by the zener diode, so that the air-conditioner detection result is accurate.
Description
Technical Field
The application relates to the technical field of electromagnetic flow measurement circuits, in particular to an explosion-proof electromagnetic flow measurement circuit.
Background
An electromagnetic flowmeter is an instrument which applies the principle of electromagnetic induction and measures the flow of conductive fluid according to the electromotive force induced when the conductive fluid passes through an externally applied magnetic field. The test electrode of the electromagnetic flowmeter needs to be inserted into a fluid medium, and if the fluid is inflammable and explosive, the fluid is easy to ignite due to electric spark or thermal effect energy possibly generated by the test electrode, and then the measurement circuit is also subjected to explosion-proof design. Since the test electrode is exposed and can only be designed in a cost-effective way, namely, the electrode energy is limited to the level that the fluid cannot be ignited, as shown in fig. 1, the solution on the market is that a safety grid circuit is arranged between the test electrode 1 and the converter 3, the safety grid consists of current limiting resistors R1-R2, zener diodes D1-D6 and fuses F1-F2, six zener diodes are respectively connected in parallel between the test electrode 1 and the ground for limiting voltage, the test electrode 1 is inserted into the test tube 6, a pair of windings 2 manufacture magnetic fields, the fluid cuts the magnetic fields to generate current, and the converter 3 converts analog electric signals sent by the electrode 1 into digital signals. The zener diode is of a high-power type, and the PN junction is a planar junction to form a large capacitance. However, the empty pipe detection function of the electromagnetic flowmeter is obtained by impedance between the test electrode and the ground, and a zener diode with a large capacitance is connected between the test electrode and the ground, so that the empty pipe detection result is easily interfered, and the accuracy of the detection result is reduced.
Disclosure of utility model
In view of the problem that in some electromagnetic flow measurement circuits in the market, a safety grid circuit is arranged between a test electrode and a converter, and is easy to interfere with the result of empty pipe detection, and the accuracy of the detection result is reduced, the application provides an explosion-proof electromagnetic flow measurement circuit so as to solve the problem. Therefore, the application adopts the following technical scheme.
An explosion-proof electromagnetic flow measuring circuit comprises a pair of test electrodes, a pair of windings, a first current limiting resistor, a second current limiting resistor, a converter, a zener diode and a fuse.
One of the test electrodes is connected in series with the first current limiting resistor, and the other test electrode is connected in series with the second current limiting resistor. The first current limiting resistor, the second current limiting resistor and the pair of windings are all connected to the signal receiving end of the converter.
The power connection end of the converter is connected to two ends of the zener diode. The fuse is connected to the power connection end of the converter and one end of the zener diode.
By adopting the technical scheme, the pair of windings can emit a magnetic field to the fluid, the fluid cuts the magnetic field to generate an electric signal, and the pair of test electrodes collect the electric signal. The zener diode is arranged at one end of the converter far away from the test electrode, namely the converter is not arranged between the test electrode and the converter, so that the converter can directly receive an electric signal sent by the test electrode, and the electric signal is not easy to receive the interference of the zener diode, so that the air-conditioner detection result is accurate.
Optionally, the explosion-proof electromagnetic flow measurement circuit further comprises a power supply. The power receiving end of the converter is connected to two ends of the power supply. The zener diode is connected between the converter and the power supply. The fuse is connected to a line between the converter and the power source.
By adopting the technical scheme, the power supply supplies power for the converter, and the zener diode and the fuse between the converter and the power supply play a role in limiting circuit voltage and energy, so that the tested conductive fluid is effectively prevented from explosion.
Optionally, the explosion-proof electromagnetic flow measurement circuit includes three zener diodes. Three of the zener diodes are connected in parallel between the zener diodes and the power supply.
By adopting the technical scheme, the three zener diodes reduce the risk of damage to the single zener diode.
Optionally, the explosion-proof electromagnetic flow measurement circuit further comprises a man-machine interaction device. The man-machine interaction equipment is connected to the signal output end of the converter.
Through adopting above-mentioned technical scheme, the converter is with the electric signal output after the conversion to man-machine interaction equipment demonstrates.
Optionally, the explosion-proof electromagnetic flow measurement circuit further comprises a first opto-isolator. The first photoelectric isolator is arranged between the man-machine interaction device and the converter.
Through adopting above-mentioned technical scheme, first photoelectric isolator keeps apart the human-computer interaction equipment with electric connection between the converter, but keeps information transmission connection, has promoted the explosion-proof reliability of circuit.
Optionally, the converter includes a conversion circuit and an excitation circuit connected to each other. The signal receiving end of the conversion circuit is connected with the first current limiting resistor and the second current limiting resistor, and the power receiving end of the conversion circuit is connected with the fuse, the zener diode and the man-machine interaction device. The excitation circuit is connected to a pair of the windings.
By adopting the technical scheme, the conversion circuit converts the analog signal into the digital signal, and the excitation circuit excites the winding to generate a magnetic field.
Optionally, the explosion-proof electromagnetic flow measurement circuit further comprises a second opto-isolator. The second opto-isolator is disposed between the conversion circuit and the excitation circuit.
By adopting the technical scheme, the second photoelectric isolator isolates the electric connection between the conversion circuit and the excitation circuit, but keeps information transmission connection, keeps the action of an excitation magnetic field, and further improves the explosion-proof reliability of the circuit.
Alternatively, a pair of the test electrodes is inserted into the test tube, and two of the test electrodes are disposed opposite to each other. A pair of said windings are oppositely disposed outside the test tube. The connection line of a pair of the windings is perpendicular to the connection line of a pair of the test electrodes.
By adopting the technical scheme, a pair of windings are excited to generate a magnetic field, the conductive fluid cuts the magnetic field to generate magnetic change and electric change, and a pair of electrodes perpendicular to the windings capture and transmit electric information.
In summary, the explosion-proof electromagnetic flow measuring circuit of the application has the following beneficial effects: the safety grid comprising the Zener diode and the fuse is arranged between the converter and the power supply, but not between the converter and the test electrode, so that the interference of the safety grid on signals sent by the test electrode is reduced, and the accuracy of a test result is improved.
Drawings
Fig. 1 is an intrinsic safety circuit diagram designed by placing a safety gate circuit between a test electrode and a converter in the background art.
Fig. 2 is a circuit diagram of one implementation of an explosion-proof electromagnetic flow measurement circuit.
Fig. 3 is a circuit diagram of another implementation of an explosion-proof electromagnetic flow measurement circuit.
Reference numerals: the testing device comprises a testing electrode 1, a winding 2, a first current limiting resistor R1, a second current limiting resistor R2, a converter 3, a zener diode D, a fuse F, a power supply 4, a man-machine interaction device 5, a first photoelectric isolator OC1, a conversion circuit 31, an excitation circuit 32, a second photoelectric isolator OC2 and a testing tube 6.
Detailed Description
Some embodiments of the explosion-proof electromagnetic flow measurement circuit of the present application are specifically described below with reference to the accompanying drawings.
Referring to fig. 2, an explosion-proof electromagnetic flow measuring circuit includes a pair of test electrodes 1, a pair of windings 2, a first current limiting resistor R1, a second current limiting resistor R2, a converter 3, a zener diode D, and a fuse F.
One of the test electrodes 1 is connected in series with the first current limiting resistor R1, and the other test electrode 1 is connected in series with the second current limiting resistor R2. The first current limiting resistor R1, the second current limiting resistor R2 and the pair of windings 2 are all connected to the signal receiving end of the converter 3.
The electrical terminals of the converter 3 are connected to two ends of the zener diode D. The fuse F is connected to the power connection terminal of the converter 3 and one end of the zener diode D.
In the explosion-proof electromagnetic flow measuring circuit, the pair of windings 2 can emit a magnetic field to a fluid, the fluid cuts the magnetic field to generate an electric signal, and the pair of test electrodes 1 collect the electric signal. The zener diode D is arranged at one end of the converter far away from the test electrode 1, namely, the converter is not arranged between the test electrode 1 and the converter 3, so that the converter is closer to the test electrode 1, the safety grid is prevented from influencing the input impedance of the empty pipe detection, the converter can directly receive weak electric signals sent by the test electrode 1, the electric signals are not easy to be interfered by the zener diode D, the empty pipe detection result is basically not influenced, and the empty pipe detection result is accurate.
In the conventional method of providing the safety barrier between the converter 3 and the test electrode 1, since the test electrode 1 is a bipolar signal, it is necessary to provide an energy-limiting voltage-limiting device and a current-limiting element between the two test electrodes 1 and the ground, respectively. According to the explosion-proof electromagnetic flow measuring circuit, only the energy-limiting voltage-limiting circuit is needed to be arranged between the power supply 4 and the conversion circuit 31, so that the consumption of components is obviously reduced, the cost is saved, and the circuit is more compact.
The explosion-proof electromagnetic flow measurement circuit may further comprise a power supply 4, and the power supply 4 may be a direct current or alternating current power supply 4. The power connection terminals of the converter 3 are connected to two ends of the power supply 4. The zener diode D is connected between the converter 3 and the power supply 4. The fuse F is connected on a line between the converter 3 and the power supply 4. The power supply 4 supplies power to the converter 3, and the zener diode D and the fuse F between the converter and the power supply 4 play a role in limiting circuit voltage and energy, so that the tested conductive fluid is effectively prevented from explosion.
Optionally, the anti-explosion electromagnetic flow measuring circuit includes three zener diodes D, which are a first zener diode D1, a second zener diode D2, and a third zener diode D3, respectively. Three of the zener diodes D are connected in parallel between the zener diode D and the power supply 4. Three of said zener diodes D reduce the risk of damage to a single zener diode D.
Optionally, the explosion-proof electromagnetic flow measuring circuit further comprises a man-machine interaction device 5. The man-machine interaction device 5 is connected to the signal output end of the converter 3. The converter 3 outputs the converted electric signals to the man-machine interaction device 5 for display.
In order to enhance the reliability of the explosion protection, the explosion protection electromagnetic flow measuring circuit further comprises a first opto-isolator OC1. The first opto-isolator OC1 is arranged between the human interaction device 5 and the converter 3. The first photoelectric isolator OC1 isolates the electrical connection between the man-machine interaction device 5 and the converter 3, but keeps information transmission connection, so that the reliability of circuit explosion prevention is improved.
In an alternative embodiment, as shown in fig. 3, the converter 3 comprises a conversion circuit 31 and an excitation circuit 32 connected to each other. The signal receiving end of the conversion circuit 31 is connected with the first current limiting resistor R1 and the second current limiting resistor R2, and the power receiving end of the conversion circuit 31 is connected with the fuse F, the zener diode D and the man-machine interaction device 5. The excitation circuit 32 is connected to a pair of the windings 2. The conversion circuit 31 converts an analog signal into a digital signal. The excitation circuit 32 excites the winding 2 to produce a magnetic field.
To further enhance the reliability of the explosion protection, the explosion protection electromagnetic flow measuring circuit further comprises a second opto-isolator OC2. The second opto-isolator OC2 is arranged between the conversion circuit 31 and the excitation circuit 32. The second opto-isolator OC2 isolates the electrical connection between the conversion circuit 31 and the excitation circuit 32, but maintains the information transmission connection, maintains the action of the excitation magnetic field, and further improves the reliability of circuit explosion protection.
A preferred arrangement is that a pair of said test electrodes 1 are inserted into a test tube 6 and that two said test electrodes 1 are arranged opposite each other. A pair of said windings 2 are oppositely arranged outside the test tube 6. The connection line of a pair of the windings 2 is perpendicular to the connection line of a pair of the test electrodes 1. A pair of windings 2 is excited to produce a magnetic field, the conductive fluid cuts the magnetic field, produces magnetic and electrical changes, and a pair of electrodes perpendicular to windings 2 captures and transmits electrical information.
The explosion-proof electromagnetic flow measuring circuit of the above embodiment is divided into two parts, namely 1) an energy-limiting voltage-limiting circuit, and consists of a fuse FF1 and zener diodes DD 1-D3, wherein the combination of the two devices limits the total output energy and the maximum output voltage. The maximum voltage is the maximum voltage-stabilizing value VZmax of the zener diode D, and the maximum energy is the maximum breaking current of the fuse F multiplied by the large voltage-stabilizing voltage; 2) The current limiting circuit is composed of current limiting resistors R1-R2 and zener diodes DD 1-D3, and limits the maximum current flowing to the intrinsic safety electrode terminal to be no more than VZmax/Rmax. The two photoelectric isolators isolate the electrical connection at two sides, so that the intrinsic safety circuit is not influenced by other non-intrinsic safety circuits, and the anti-interference capability is enhanced.
The above embodiments are merely examples of the present application, and the protection scope of the present application is not limited to the above embodiments, and it should be obvious to those skilled in the art that several modifications and variations are possible without departing from the inventive concept.
Claims (8)
1. An explosion-proof electromagnetic flow measuring circuit is characterized by comprising a pair of test electrodes (1), a pair of windings (2), a first current limiting resistor (R1), a second current limiting resistor (R2), a converter (3), a zener diode (D) and a fuse (F);
One of the test electrodes (1) is connected in series with the first current limiting resistor (R1), and the other test electrode (1) is connected in series with the second current limiting resistor (R2); the first current limiting resistor (R1), the second current limiting resistor (R2) and a pair of windings (2) are all connected to a signal receiving end of the converter (3);
The power connection end of the converter (3) is connected to the two ends of the zener diode (D); the fuse (F) is connected to the power connection end of the converter (3) and one end of the zener diode (D).
2. The explosion-proof electromagnetic flow measurement circuit according to claim 1, further comprising a power supply (4); the power connection end of the converter (3) is connected to the two ends of the power supply (4); the zener diode (D) is connected between the converter (3) and the power supply (4); the fuse (F) is connected on the line between the converter (3) and the power supply (4).
3. The explosion-proof electromagnetic flow measurement circuit according to claim 2, characterized in that it comprises three of said zener diodes (D); three zener diodes (D) are connected in parallel between the zener diodes (D) and the power supply (4).
4. The explosion-proof electromagnetic flow measurement circuit according to claim 1, characterized in that it further comprises a human-machine interaction device (5); the man-machine interaction device (5) is connected to the signal output end of the converter (3).
5. The explosion-proof electromagnetic flow measurement circuit according to claim 4, further comprising a first opto-isolator (OC 1); the first opto-isolator (OC 1) is arranged between the human-computer interaction device (5) and the converter (3).
6. The explosion-proof electromagnetic flow measurement circuit according to claim 4, wherein the converter (3) comprises a conversion circuit (31) and an excitation circuit (32) connected to each other;
The signal receiving end of the conversion circuit (31) is connected with the first current limiting resistor (R1) and the second current limiting resistor (R2), and the power receiving end of the conversion circuit (31) is connected with the fuse (F), the zener diode (D) and the man-machine interaction equipment (5);
The excitation circuit (32) is connected to a pair of the windings (2).
7. The explosion-proof electromagnetic flow measurement circuit according to claim 6, further comprising a second opto-isolator (OC 2); the second opto-isolator (OC 2) is arranged between the conversion circuit (31) and the excitation circuit (32).
8. The explosion-proof electromagnetic flow measurement circuit according to claim 1, wherein a pair of the test electrodes (1) are inserted into a test tube (6), and two of the test electrodes (1) are disposed opposite to each other;
A pair of windings (2) are oppositely arranged outside the test tube (6); the connection line of a pair of the windings (2) is perpendicular to the connection line of a pair of the test electrodes (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202323206005.3U CN221006426U (en) | 2023-11-25 | 2023-11-25 | Explosion-proof electromagnetic flow measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202323206005.3U CN221006426U (en) | 2023-11-25 | 2023-11-25 | Explosion-proof electromagnetic flow measuring circuit |
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| Publication Number | Publication Date |
|---|---|
| CN221006426U true CN221006426U (en) | 2024-05-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202323206005.3U Active CN221006426U (en) | 2023-11-25 | 2023-11-25 | Explosion-proof electromagnetic flow measuring circuit |
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| CN (1) | CN221006426U (en) |
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2023
- 2023-11-25 CN CN202323206005.3U patent/CN221006426U/en active Active
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