An interference-resistant electromagnetic flowmeter

Abstract

The application belongs to the technical field of electromagnetic flowmeters, and particularly relates to an anti-interference electromagnetic flowmeter, which comprises a measuring pipe, the inner wall of the measuring pipe is provided with an insulating lining, the outer wall of the measuring pipe is symmetrically provided with an upper double-layer shielding excitation coil and a lower double-layer shielding excitation coil, the inner wall of the measuring pipe is provided with two symmetrically arranged measuring electrodes, the outer wall of the measuring pipe is fixedly connected with an outer shell which is arranged outside the upper double-layer shielding excitation coil and the lower double-layer shielding excitation coil, and the side wall of the outer shell is connected with a sensor. The application can resist external electromagnetic interference, ensure the stability of the measuring magnetic field, supplement conductive particles to low-conductivity medium to realize accurate measurement, and can recover the conductive particles after measurement in stages to avoid the pollution of downstream medium due to deterioration, and the particles can be recycled and reused to avoid resource waste.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic flowmeter technology, and in particular relates to an anti-interference electromagnetic flowmeter. Background Technology

[0002] Electromagnetic flowmeters rely on Faraday's law of electromagnetic induction to detect the flow of conductive media. Due to their advantages such as no pressure loss in pipelines, stable measurement accuracy, and wide applicability, they are widely used in industrial flow monitoring and control fields such as chemical, environmental protection, metallurgy, and water supply and drainage. The excitation coil is the core functional component of the electromagnetic flowmeter; the stability and uniformity of the magnetic field it generates directly affect the overall measurement accuracy and anti-interference capability of the instrument. Compared to the traditional single-layer excitation coil structure, anti-interference electromagnetic flowmeters equipped with upper and lower double-layer shielded excitation coils have superior performance. This symmetrical double-layer shielding structure forms a comprehensive magnetic field protection system, effectively blocking various external electromagnetic interferences such as industrial frequency electric fields, inverter harmonics, and stray magnetic fields from external equipment. It prevents external noise from disturbing the magnetic field in the detection area, ensuring a uniform and stable working magnetic field, and improving the accuracy and stability of flow detection under complex electromagnetic conditions.

[0003] Although the double-layer shielded excitation structure effectively improves the anti-interference performance of electromagnetic flowmeters, the working principle of electromagnetic flowmeters mainly relies on the continuous and stable induced electromotive force signal generated after the medium cuts the uniform magnetic field, thereby achieving accurate flow conversion. However, some media have a small number of conductive particles and weak conductivity, and the induced electromotive force signal generated by the medium cutting the magnetic field lines is relatively weak with a very low effective signal amplitude. This weak signal is easily overwhelmed by the background noise of the instrument circuit and residual electromagnetic interference signals, causing the signal acquisition unit to be unable to accurately distinguish the effective detection signal, thus causing problems such as signal distortion, data jumps, and numerical drift.

[0004] Therefore, an anti-interference electromagnetic flowmeter is proposed to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned problems by providing an anti-interference electromagnetic flowmeter.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an anti-interference electromagnetic flowmeter, comprising a measuring tube, wherein the inner wall of the measuring tube is provided with an insulating lining, and the outer wall of the measuring tube is symmetrically provided with an upper double-layer shielded excitation coil and a lower double-layer shielded excitation coil, the inner wall of the measuring tube is provided with two symmetrically arranged measuring electrodes, and the outer wall of the measuring tube is fixedly connected with a housing covering the outer side of the upper double-layer shielded excitation coil and the lower double-layer shielded excitation coil, and a sensor is connected to the side wall of the housing, and further comprising: A fabric assembly is disposed on the inner wall of the measuring tube. The fabric assembly is located upstream of the measuring tube and is connected to the feeding assembly, enabling it to deliver conductive particles into the medium. An electromagnetic grid assembly is connected to the inlet of a measuring tube. The electromagnetic grid assembly is located downstream of the measuring tube and is capable of magnetically attracting and recovering conductive particles. The filter assembly, located at the outlet of the electromagnetic grid assembly, is capable of filtering out remaining conductive particles.

[0007] In the aforementioned anti-interference electromagnetic flowmeter, the fabric assembly includes an annular tube fixedly connected to the inner wall of an insulating lining. The inner wall of the annular tube is fixedly connected to multiple horizontal tubes, and the walls of the horizontal tubes are connected to multiple short tubes. The short tubes are positioned close to the measuring electrodes.

[0008] In the aforementioned anti-interference electromagnetic flowmeter, the annular tube is provided with a turbulence fan blade on the side near the measuring electrode, and the turbulence fan blade is rotatably connected to the intermediate horizontal tube.

[0009] In the aforementioned anti-interference electromagnetic flowmeter, the feeding assembly includes a mixing tank located on one side of the measuring tube. A conveying pump is connected to the side wall of the mixing tank. The inlet end of the conveying pump is connected to the mixing tank. The outlet end of the conveying pump is fixedly connected to an outlet pipe. The end of the outlet pipe away from the conveying pump passes through the measuring tube and the insulating lining and is connected to the annular pipe. A stirring mechanism is provided inside the mixing tank.

[0010] In the aforementioned anti-interference electromagnetic flowmeter, the electromagnetic grid assembly includes a first recovery cover, which is connected to the discharge end of the measuring tube. Multiple electromagnetic rods are fixedly connected to the upper inner wall of the first recovery cover, and a recovery pipe is fixedly connected to the lower side wall of the first recovery cover. A first control valve is provided inside the recovery pipe.

[0011] In the aforementioned anti-interference electromagnetic flowmeter, each of the electromagnetic rods is fitted with an annular flushing head on its outer wall. The same arc-shaped pipe connects two adjacent annular flushing heads. One of the arc-shaped pipes is fixedly connected to a flushing pipe. The upper end of the flushing pipe extends out of a first recovery cover and is connected to an external pump. A second control valve is provided inside the flushing pipe.

[0012] In the aforementioned anti-interference electromagnetic flowmeter, the filter assembly includes a second recovery hood connected to the discharge end of the first recovery hood. A mounting bracket is fixedly connected to the inner wall of the second recovery hood, and multiple filter screens are fixedly connected to the inner wall of the mounting bracket. The mesh size of the multiple filter screens decreases sequentially along the arrangement direction away from the measuring tube.

[0013] In the aforementioned anti-interference electromagnetic flowmeter, a conveying pipe is fixedly connected to the end of the second recovery hood away from the first recovery hood. A third control valve is provided inside the conveying pipe, and a fourth control valve is provided inside the measuring pipe. A backflush pipe is connected to the upper side wall of the second recovery hood, and the backflush pipe is connected to an external pump. A gate valve is provided inside the backflush pipe.

[0014] Compared with existing technologies, the advantages of an anti-interference electromagnetic flowmeter are: When measuring media with substandard conductivity, the electromagnetic flowmeter of this invention uses a delivery pump to transport liquid containing conductive particles from a mixing tank to an annular pipe via a discharge pipe. The liquid containing conductive particles is then released into the medium within the measuring tube through a horizontal pipe and a short pipe. The conductive particles are further mixed by turbulence-inducing fan blades. The medium carrying the conductive particles flows through the measuring tube and cuts the magnetic fields generated by the upper and lower double-shielded excitation coils. The measuring electrode can then stably collect the effective induced electromotive force. The sensor receives the weak signal from the electrode, amplifies and processes it, converts it into a real-time flow value, and outputs the corresponding signal.

[0015] In this invention, after the conductive particles carried by the medium pass through the measuring electrode, a large number of conductive particles are first adsorbed by multiple electromagnetic rods to reduce the content of conductive particles in the medium. A small number of conductive particles are filtered by multiple filter plates after passing through the electromagnetic rods, thereby avoiding the problem of conductive particles remaining in the medium for a long time, changing the original physical and chemical properties of the medium, and causing material contamination in subsequent processes.

[0016] In this invention, after the electromagnetic flowmeter finishes working and the medium in the measuring pipe is completely discharged, the third and fourth control valves are closed. Subsequently, the external pump equipment delivers flushing liquid to the flushing pipe and the backflushing pipe. The flushing pipe delivers the flushing liquid through multiple arc-shaped pipes to multiple annular flushing heads for spraying. The water flow washes off the conductive particles on the surface of the demagnetized electromagnetic rod and discharges them through the recovery pipe. The backflushing pipe delivers the flushing liquid to the second recovery hood to backflush and clean the conductive particles on the surface of multiple filter screens. The conductive particles on the surface of the filter screens are then carried by the water flow into the first recovery hood and discharged through the recovery pipe. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an anti-interference electromagnetic flowmeter provided by the present invention; Figure 2 This is a schematic diagram showing the position of the measuring electrodes in this invention; Figure 3 This is a schematic diagram of the fabric assembly in this invention; Figure 4 This is a schematic diagram showing the position of the electromagnetic rod in this invention; Figure 5This is a schematic diagram of the electromagnetic grid assembly in this invention; Figure 6 This is a schematic diagram of the structure of the filter component in this invention.

[0018] In the diagram: 1 Measuring tube, 2 Insulating lining, 3 Upper double-layer shielded excitation coil, 4 Lower double-layer shielded excitation coil, 5 Measuring electrode, 6 Housing, 7 Sensor, 8 Fabric assembly, 81 Ring tube, 82 Horizontal tube, 9 Short tube, 10 Turbulent fan blade, 11 Feeding assembly, 111 Mixing box, 112 Conveying pump, 12 Discharge pipe, 13 Electromagnetic grid assembly, 131 First recovery hood, 132 Electromagnetic rod, 14 Recovery pipe, 15 First control valve, 16 Ring flushing head, 17 Arc tube, 18 Flushing pipe, 19 Second control valve, 20 Filter assembly, 201 Second recovery hood, 202 Mounting bracket, 21 Filter screen, 22 Conveying pipe, 23 Third control valve, 24 Fourth control valve, 25 Backflush pipe, 26 Gate valve. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] like Figures 1-2 As shown, an anti-interference electromagnetic flowmeter includes a measuring tube 1, an insulating lining 2 on the inner wall of the measuring tube 1, an upper double-layer shielded excitation coil 3 and a lower double-layer shielded excitation coil 4 symmetrically arranged on the outer wall of the measuring tube 1, two symmetrically arranged measuring electrodes 5 on the inner wall of the measuring tube 1, and a housing 6 fixedly connected to the outer wall of the measuring tube 1, covering the outer side of the upper double-layer shielded excitation coil 3 and the lower double-layer shielded excitation coil 4. A sensor 7 is connected to the side wall of the housing 6.

[0021] In practical use, this embodiment uses an upper double-shielded excitation coil 3 and a lower double-shielded excitation coil 4. The upper double-shielded excitation coil 3 and the lower double-shielded excitation coil 4 are composed of five layers, from the inside out, covering the excitation winding body, the inner conductive shielding layer, the middle insulating isolation layer, the outer magnetic shielding layer, and the insulating protective skeleton. The double-shielded excitation coil isolates the excitation electric field from leakage through the inner conductive shielding and blocks external stray magnetic field interference through the outer magnetic shielding. In conjunction with the middle insulating layer, it avoids eddy current loss of the shielding layer. It can not only concentrate the coil magnetic flux to improve the uniformity of the magnetic field inside the tube, stabilize the electrode induction signal, and reduce the zero-point drift of flow measurement, but also isolate and protect the winding in multiple layers, reduce the risk of temperature drift and insulation failure, and adapt to strong electromagnetic interference conditions such as the vicinity of frequency converters and high-power motors, and maintain high-precision and stable measurement for a long time.

[0022] like Figure 1 and Figure 3As shown, further, in this embodiment, the fabric assembly 8 is disposed on the inner wall of the measuring tube 1. The fabric assembly 8 is located upstream of the measuring tube 1 and is connected to the feeding assembly 11, enabling it to transport conductive particles into the medium. The fabric assembly 8 includes an annular tube 81 fixedly connected to the inner wall of the insulating liner 2. The inner wall of the annular tube 81 is fixedly connected to multiple horizontal tubes 82, and the walls of the horizontal tubes 82 are connected to multiple short tubes 9. The short tubes 9 are disposed near the measuring electrode 5. A turbulence fan blade 10 is provided on the side of the annular tube 81 near the measuring electrode 5. The turbulence fan blade 10 and the intermediate horizontal tube 82 rotate. The connection and feeding assembly 11 includes a mixing chamber 111 located on one side of the measuring tube 1. A conveying pump 112 is connected to the side wall of the mixing chamber 111. The inlet end of the conveying pump 112 is connected to the mixing chamber 111. The outlet end of the conveying pump 112 is fixedly connected to the outlet pipe 12. The end of the outlet pipe 12 away from the conveying pump 112 passes through the measuring tube 1 and the insulating lining 2 and is connected to the annular pipe 81. The mixing chamber 111 is equipped with a stirring mechanism (the stirring mechanism includes a stirring motor and a stirring frame. The stirring motor drives the stirring frame to rotate, which can stir the liquid and the conductive particles of iron oxide).

[0023] In actual use, in this embodiment, the liquid mixed with conductive particles in the mixing tank 111 is transported to the annular pipe 81 through the discharge pipe 12 by the delivery pump 112. Subsequently, the liquid mixed with conductive particles is transported to the horizontal pipe 82 and discharged through the short pipe 9. During the flow of the medium in the measuring pipe 1, the turbulence fan blade 10 rotates under the impact of the medium, thereby mixing the liquid mixed with conductive particles with the medium (the liquid raw material and the medium are the same). The medium carrying conductive particles flows through the measuring pipe 1 and cuts the magnetic field generated by the upper double-layer shielded excitation coil 3 and the lower double-layer shielded excitation coil 4. The measuring electrode 5 can then stably collect the effective induced electromotive force.

[0024] like Figure 4 and Figure 5 As shown, in this embodiment, the electromagnetic grid assembly 13 is connected to the port of the measuring tube 1. The electromagnetic grid assembly 13 is located downstream of the measuring tube 1 and can magnetically recycle conductive particles. The electromagnetic grid assembly 13 includes a first recycling cover 131, which is connected to the discharge end of the measuring tube 1. Multiple electromagnetic rods 132 are fixedly connected to the upper inner wall of the first recycling cover 131.

[0025] In actual use, in this embodiment, when the medium carrying conductive particles flows from the measuring tube 1 into the first recovery hood 131, most of the conductive particles will be attracted by the electromagnetic rod 132 (the conductive particles are iron oxide, which can be attracted by the electromagnetic rod 132).

[0026] like Figure 6As shown, in this embodiment, the filter assembly 20 is disposed at the discharge port of the electromagnetic grid assembly 13 and can filter the remaining conductive particles. The filter assembly 20 includes a second recovery cover 201 that is connected to the discharge end of the first recovery cover 131. A mounting bracket 202 is fixedly connected to the inner wall of the second recovery cover 201. A plurality of filter screens 21 are fixedly connected to the inner wall of the mounting bracket 202. The mesh size of the plurality of filter screens 21 decreases sequentially along the arrangement direction away from the measuring tube 1.

[0027] In actual use, in this embodiment, when the medium carrying a small amount of conductive particles passes through the second recovery cover 201, the small amount of conductive particles can be filtered by the multiple filter screens 21 set in the mounting frame 202.

[0028] like Figure 1 , Figures 4-6 As shown, in this embodiment, each electromagnetic rod 132 is fitted with an annular flushing head 16 on its outer wall. Two adjacent annular flushing heads 16 are connected by the same arc-shaped pipe 17. The wall of one arc-shaped pipe 17 is fixedly connected to a flushing pipe 18. The upper end of the flushing pipe 18 extends out of the first recovery cover 131 and is connected to an external pump. A second control valve 19 is provided inside the flushing pipe 18. The end of the second recovery cover 201 away from the first recovery cover 131 is fixedly connected to a conveying pipe 22. A third control valve 23 is provided inside the conveying pipe 22. A fourth control valve 24 is provided inside the measuring pipe 1. The upper side wall of the second recovery cover 201 is connected to a backflush pipe 25. The backflush pipe 25 is connected to an external pump. A gate valve 26 is provided inside the backflush pipe 25. The lower side wall of the first recovery cover 131 is fixedly connected to a recovery pipe 14. A first control valve 15 is provided inside the recovery pipe 14.

[0029] In actual use, in this embodiment, after the measurement work is completed and the medium in the measuring tube 1 is completely discharged, the external controller will control the third control valve 23 and the fourth control valve 24 to close. Then, the external pump equipment will be controlled to deliver the flushing liquid to the flushing pipe 18 and the backflushing pipe 25. The flushing pipe 18 will deliver the flushing liquid through multiple arc-shaped pipes 17 to multiple annular flushing heads 16 for spraying. The water flow will wash off the conductive particles on the surface of the demagnetized electromagnetic rod 132 and discharge it through the recovery pipe 14. The backflushing pipe 25 will deliver the flushing liquid to the second recovery hood 201 to backflush and clean the conductive particles on the surface of multiple filter screens 21. The conductive particles on the surface of the filter screens 21 will flow into the first recovery hood 131 under the action of the water flow and be discharged through the recovery pipe 14.

[0030] The operating principle of this invention is explained as follows: When measuring a medium with substandard conductivity using an electromagnetic flowmeter, the conductive particles of iron oxide are conveyed to the cloth assembly 8 through the feeding assembly 11 and evenly dispersed. This allows the conductive particles carried by the medium to cut the magnetic fields generated by the upper double-shielded excitation coil 3 and the lower double-shielded excitation coil 4. The measuring electrode 5 can then stably collect the effective induced electromotive force. The sensor 7 receives the weak signal from the electrode and performs amplification, calculation, and processing to obtain the real-time flow value and output the corresponding signal. After the conductive particles carried by the medium flow out of the measuring tube 1, the conductive particles in the medium are separated and recovered by the electromagnetic grid assembly 13 and the filter assembly 20. This avoids the problem of conductive particles remaining in the medium for a long time, changing the original physical and chemical properties of the medium, and causing material contamination in subsequent processes.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An anti-interference electromagnetic flowmeter, comprising a measuring tube (1), wherein the inner wall of the measuring tube (1) is provided with an insulating lining (2), and the outer wall of the measuring tube (1) is symmetrically provided with an upper double-layer shielded excitation coil (3) and a lower double-layer shielded excitation coil (4), the inner wall of the measuring tube (1) is provided with two symmetrically arranged measuring electrodes (5), and the outer wall of the measuring tube (1) is fixedly connected with a housing (6) covering the outer side of the upper double-layer shielded excitation coil (3) and the lower double-layer shielded excitation coil (4), and a sensor (7) is connected to the side wall of the housing (6), characterized in that, Also includes: The electromagnetic grid assembly (13) is connected to the port of the measuring tube (1). The electromagnetic grid assembly (13) is located downstream of the measuring tube (1) and can magnetically attract and recover conductive particles. The filter assembly (20) is installed at the outlet of the electromagnetic grid assembly (13) and can filter the remaining conductive particles.

2. The anti-interference electromagnetic flowmeter according to claim 1, characterized in that, The inner wall of the measuring tube (1) is provided with a cloth assembly (8). The cloth assembly (8) is located upstream of the measuring tube (1). The cloth assembly (8) is connected to the feeding assembly (11) and can deliver conductive particles into the medium. The conductive particles are iron oxide. The cloth assembly (8) includes an annular tube (81) fixedly connected to the inner wall of the insulating lining (2). The inner wall of the annular tube (81) is fixedly connected to multiple horizontal tubes (82). The wall of the horizontal tubes (82) is connected to multiple short tubes (9). The short tubes (9) are set close to the measuring electrode (5).

3. The anti-interference electromagnetic flowmeter according to claim 2, characterized in that, The annular tube (81) is provided with a turbulence fan blade (10) on the side near the measuring electrode (5), and the turbulence fan blade (10) and the middle horizontal tube (82) are rotatably connected.

4. The anti-interference electromagnetic flowmeter according to claim 2, characterized in that, The feeding assembly (11) includes a mixing chamber (111) located on one side of the measuring tube (1). A conveying pump (112) is connected to the side wall of the mixing chamber (111). The feed end of the conveying pump (112) is connected to the mixing chamber (111). The discharge end of the conveying pump (112) is fixedly connected to the discharge pipe (12). The end of the discharge pipe (12) away from the conveying pump (112) passes through the measuring tube (1) and the insulating lining (2) and is connected to the annular pipe (81). A stirring mechanism is provided inside the mixing chamber (111).

5. The anti-interference electromagnetic flowmeter according to claim 1, characterized in that, The electromagnetic grid assembly (13) includes a first recycling hood (131), which is connected to the discharge end of the measuring tube (1). Multiple electromagnetic rods (132) are fixedly connected to the upper inner wall of the first recycling hood (131), and a recycling tube (14) is fixedly connected to the lower side wall of the first recycling hood (131). A first control valve (15) is provided inside the recycling tube (14).

6. The anti-interference electromagnetic flowmeter according to claim 5, characterized in that, Each of the electromagnetic rods (132) is fitted with an annular flushing head (16) on its outer wall. The two adjacent annular flushing heads (16) are connected by the same arc-shaped pipe (17). The wall of one of the arc-shaped pipes (17) is fixedly connected to a flushing pipe (18). The upper end of the flushing pipe (18) extends out of the first recovery cover (131) and is connected to an external pump. A second control valve (19) is provided inside the flushing pipe (18).

7. The anti-interference electromagnetic flowmeter according to claim 5, characterized in that, The filter assembly (20) includes a second recycling hood (201) connected to the discharge end of the first recycling hood (131). The inner wall of the second recycling hood (201) is fixedly connected to a mounting frame (202). The inner wall of the mounting frame (202) is fixedly connected to a plurality of filter screens (21). The mesh size of the plurality of filter screens (21) decreases sequentially along the arrangement direction away from the measuring tube (1).

8. The anti-interference electromagnetic flowmeter according to claim 7, characterized in that, The second recovery hood (201) is fixedly connected to a conveying pipe (22) at the end away from the first recovery hood (131). A third control valve (23) is provided in the conveying pipe (22), and a fourth control valve (24) is provided in the measuring pipe (1). A backflush pipe (25) is connected to the upper side wall of the second recovery hood (201). The backflush pipe (25) is connected to an external pump. A gate valve (26) is provided in the backflush pipe (25).

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