Electromagnetic flowmeter

Abstract

The invention relates to the technical field of electromagnetic flow meters, in particular to an electromagnetic flow meter which comprises a flow meter shell and a switchable induction inner core, the flow meter shell comprises an outer sleeve shell, the switchable induction inner core comprises a measuring inner pipe, the measuring inner pipe is installed on the inner side of the outer sleeve shell, and the outer sleeve shell is installed on the inner side of the measuring inner pipe. The outer sleeve is fixedly installed on the outer wall of the measuring inner pipe, the two ends of the outer wall of the outer sleeve are each provided with a pair of telescopic induction electrodes, and a rotary excitation coil is installed on the outer wall of the outer sleeve in a sliding mode. When the conditions of fluid layering, electrode surface scaling or fluid turbulence are detected, only the rotary excitation coil needs to be controlled to slide to the other end of the outer sleeve, the telescopic induction electrode at the other end is pressed and triggered at the same time, and the detection positions of the excitation coil and the induction electrode are changed, so that the effect of cleaning the induction electrode is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic flowmeters, and particularly relates to an electromagnetic flowmeter. Background Art

[0002] An electromagnetic flowmeter is a flow measurement instrument based on Faraday's law of electromagnetic induction, used to measure the flow rate of conductive liquids or slurries. Its working principle is to convert the flow velocity of the conductive liquid flowing through the pipeline into an electrical signal through the principle of electromagnetic induction, so as to measure the flow rate; Existing electromagnetic flowmeters usually have a pair of excitation coils and a pair of induction electrodes, and the positions of the excitation coils and electrodes are fixed. Based on this structural characteristic, the following problems may occur during the use of existing electromagnetic flowmeters: 1. The installation angle of the electrodes inside the electromagnetic flowmeter has a certain influence on the flow measurement. If there are serious bubbles, impurities or stratification phenomena in the measured fluid, and by chance the installation directions of the two electrodes are perpendicular to the stratified fluid, this will cause the two electrodes to be in different layers, and the conductivity of the fluid in different layers is different, which may increase the measurement error of the electrodes and greatly affect the measurement accuracy of the electromagnetic flowmeter; 2. Under certain working conditions, the fluid may contain solid particles, sediments or other chemical components. These substances may deposit or scale on the electrode surface. Due to the fixed position of the electrodes, pollutants or scale deposits may accumulate on the electrode surface after long-term operation. The accumulated pollutants or scale deposits may reduce the contact quality between the electrodes and the fluid, resulting in measurement errors or signal attenuation; 3. When the fluid flow state inside the electromagnetic flowmeter fluctuates violently or becomes turbulent, the electrodes and excitation coils at fixed positions may not be able to adapt to this change. If the turbulent position happens to overlap with the positions of the electrodes and excitation coils, this may cause the induced voltage signal to be unstable or distorted, and the accuracy of the measurement signal may be affected; Therefore, it is necessary to invent an electromagnetic flowmeter. Summary of the Invention

[0003] In order to achieve the above object, the present invention provides the following technical solution: An electromagnetic flowmeter, comprising a flowmeter housing and a switchable induction inner core; The flowmeter housing includes an outer housing, connecting pipes are installed at both ends of the outer housing, flange plates are installed at the ends of the connecting pipes away from the outer housing, a processor housing is installed on the top surface of the outer housing, an electrical interface is provided on the processor housing, a signal processor is installed inside the processor housing, and bolts are installed between the outer housing and the processor housing; The switchable induction core includes a measuring inner tube, which is installed on the inner side of the outer shell, and the measuring inner tube is installed on the inner side of the connecting tube. The outer wall of the measuring inner tube fits the inner wall of the connecting tube. A sliding component is installed on the outer wall of the measuring inner tube. The sliding component includes an outer sleeve, and the outer sleeve is fixedly installed on the outer wall of the measuring inner tube. A pair of telescopic induction electrodes are respectively arranged at both ends of the outer wall of the outer sleeve. A rotating excitation coil is slidably installed on the outer wall of the outer sleeve. The rotating excitation coil is used to slide on both ends of the outer sleeve and press to trigger the corresponding telescopic induction electrodes.

[0004] Preferably, the sliding assembly includes a fixing ring, which is fixedly mounted at both ends of the outer sleeve, and deflection grooves are provided on opposite sides of the outer sleeve, and the deflection grooves are obliquely deflected 90° along the outer wall of the measuring inner tube. A pair of beveled protrusions are provided on the side of the fixing ring close to the outer sleeve, and the beveled protrusions on the fixing ring are mounted at both ends of the deflection groove on the outer sleeve.

[0005] Preferably, the rotary excitation coil includes a coil seat, two of the coil seats are relatively arranged on both sides of the outer sleeve, a deflection slider is fixedly installed on the side of the coil seat close to the outer sleeve, oblique cuts are arranged at both ends of the deflection slider, the deflection slider is slidably installed in the deflection slide groove, and the deflection slider slides along the deflection slide groove.

[0006] Preferably, the rotary excitation coil includes a rotating clamp, which is fixedly mounted on one side of the coil seat, a thrust ring is installed on the side of the rotating clamp away from the coil seat, openings are provided on the upper and lower sides of the thrust ring, a hydraulic rod is fixedly mounted on the outer wall of the connecting tube on the side of the thrust ring away from the rotating clamp, and the output end of the hydraulic rod passes through the outer shell and is fixedly connected to the thrust ring.

[0007] Preferably, the rotary excitation coil includes an electromagnetic wire, which is wound on a coil seat. A coil connector is provided on the side of the coil seat away from the outer sleeve. One end of the coil connector passes through the coil seat and is electrically connected to the electromagnetic wire, and the other end of the coil connector is connected to the coil wire. One end of the coil wire away from the coil connector extends upward into the processor housing and is electrically connected to the electrical interface.

[0008] Preferably, the rotary excitation coil includes a pressing slider, which is fixedly installed between the adjacent ends of two coil seats. The pressing slider and the coil seat form an annular structure. The pressing slider is provided with convex plates on both sides close to the connecting tube, and the convex plates on both sides of the pressing slider are tilted in the direction away from the outer sleeve.

[0009] Preferably, an induction joint is fixedly installed in the middle of the pressing slider. The induction joint penetrates through the pressing slider. One end of the induction joint away from the surface of the outer sleeve is electrically connected to an induction wire. A processor interface is provided at the bottom of the signal processor. One end of the induction wire away from the induction joint extends upward into the processor housing and is electrically connected to the processor interface.

[0010] Preferably, outer tube openings are provided on the upper and lower sides of the outer shell near one end of the hydraulic rod, and outer tube openings are also provided on the transverse sides of the outer shell away from the hydraulic rod. Inner tube openings are provided at positions on the inner wall of the measuring inner tube close to the outer tube openings.

[0011] Preferably, the telescopic induction electrode includes an electrode. Four electrodes are respectively slidably inserted into the respective outer tube openings on the surface of the outer shell. An airtight ring is provided on one side of the outer tube opening close to the surface of the outer shell. The airtight ring is sleeved on the outside of the electrode. An air injection port is provided on one side of the airtight ring. Pressurized gas is injected into the airtight ring. Granular protrusions are provided on the surface of the airtight ring.

[0012] Preferably, the telescopic induction electrode includes an air ring bracket. The air ring bracket is sleeved on the surface of the airtight ring away from the outer shell. The air ring bracket is fixedly connected to the outer shell. An electrode cap is fixedly installed at one end of the electrode away from the outer shell. A spring is provided between the electrode cap and the air ring bracket. The spring is installed on the outer wall of the electrode.

[0013] The beneficial effects of the present invention are as follows: Through the rotary excitation coil that can slide between the two ends of the outer sleeve, the corresponding telescopic induction electrode is triggered by pressing. When the rotary excitation coil is located at one end of the outer sleeve, the telescopic induction electrode at this end is triggered by pressing. The telescopic induction electrode extends into the inner wall of the measuring inner tube and measures. When encountering the situation of fluid stratification, scale formation on the electrode surface, or fluid turbulence in the detection fluid, only need to control the rotary excitation coil to slide to the other end of the outer sleeve, and at the same time press to trigger the telescopic induction electrode at the other end. At the same time, the dirt on the surface is automatically peeled off during the retraction of the scaling electrode, so as to achieve the effect of changing the detection positions of the excitation coil and the induction electrode, and cleaning the induction electrode, enabling it to flexibly cope with situations such as fluid stratification, scale formation on the electrode surface, or fluid turbulence in the detection fluid, and effectively improving the measurement accuracy of the electromagnetic flowmeter. Description of the Drawings

[0014] Figure 1 is the external view provided by the present invention; Figure 2 is the schematic internal structure diagram of the outer shell provided by the present invention; Figure 3 is the schematic internal structure diagram provided by the present invention; Figure 4 is the schematic diagram of the sliding of the rotary excitation coil provided by the present invention; Figure 5 Side view cross-sectional view provided by the present invention; Figure 6 Schematic diagram before the telescopic induction electrode of the present invention is triggered; Figure 7 Schematic diagram after the telescopic induction electrode of the present invention is triggered; Figure 8 Schematic diagram for measuring the inner wall of the inner tube provided by the present invention; Figure 9 Internal detail view of the outer casing provided by the present invention; Figure 10 Installation schematic diagram of the coil seat provided by the present invention; Figure 11 Exploded view of the coil seat provided by the present invention; Figure 12 Exploded view of the telescopic induction electrode provided by the present invention; Figure 13 Schematic diagram of the electrode being pressed down provided by the present invention; Figure 14 Cross-sectional view of the airtight ring in the state where the electrode is pressed down provided by the present invention; Figure 15 Schematic diagram of the electrode being lifted provided by the present invention; Figure 16 Cross-sectional view of the airtight ring in the state where the electrode is lifted provided by the present invention.

[0015] In the figure: 111, outer casing; 112, connecting pipe; 113, flange; 114, processor housing; 115, electrical interface; 116, bolt; 121, measuring inner tube; 122, inner tube opening; 131, outer tube; 132, fixing ring; 133, deflection chute; 134, outer tube opening; 141, propulsion ring; 142, hydraulic rod; 151, coil seat; 152, rotating fastener; 153, electromagnetic wire; 154, coil joint; 155, coil wire; 156, deflection slider; 161, airtight ring; 162, air ring support; 163, electrode; 164, electrode cap; 165, spring; 171, pressing slider; 172, induction joint; 173, induction wire; 174, processor interface; 175, signal processor. Detailed implementation manners

[0016] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0017] Example 1, as Figure 1 - Figure 7As shown in the figure, an electromagnetic flowmeter according to an embodiment of the first aspect of the present invention includes a flowmeter housing and a switchable induction core; The flowmeter housing includes an outer jacket 111. Connecting pipes 112 are installed at both ends of the outer jacket 111. Flange plates 113 are installed at the ends of the connecting pipes 112 away from the outer jacket 111. A processor housing 114 is installed on the top surface of the outer jacket 111. An electrical interface 115 is provided on the processor housing 114. A signal processor 175 is installed inside the processor housing 114. Bolts 116 are installed between the outer jacket 111 and the processor housing 114; The switchable induction core includes a measuring inner tube 121. The measuring inner tube 121 is installed inside the outer jacket 111. The measuring inner tube 121 is installed inside the connecting pipe 112. The outer wall of the measuring inner tube 121 is in contact with the inner wall of the connecting pipe 112. A sliding assembly is installed on the outer wall of the measuring inner tube 121. The sliding assembly includes an outer sleeve 131. The outer sleeve 131 is fixedly installed on the outer wall of the measuring inner tube 121. A pair of telescopic induction electrodes are respectively provided at both ends of the outer wall of the outer sleeve 131. A rotary excitation coil is slidably installed on the outer wall of the outer sleeve 131. The rotary excitation coil is used to slide at both ends of the outer sleeve 131 and press to trigger the corresponding telescopic induction electrode.

[0018] In the above embodiment, it should be noted that threaded holes are provided on both the outer jacket 111 and the processor housing 114. The bolts 116 are screwed into the threaded holes of the outer jacket 111 and the processor housing 114. The flange plate 113 is used to connect the fluid pipeline. By connecting the flange plates 113 at the upper ends of the connecting pipes 112 at both ends of the outer jacket 111 to the fluid pipeline, the effect of accessing the fluid pipeline is achieved; the processor housing 114 is used to protect the signal processor 175. The signal processor 175 is externally connected to a power supply. The signal processor 175 is built-in with a remote signal sending module for linkage with a remote display device. After receiving the voltage signal from the electrode, the signal processor 175 performs processing such as amplification, filtering, and conversion, and finally outputs an electrical signal proportional to the flow rate. This electrical signal can be converted into a flow rate value, and the flow rate data is displayed through a display or a remote device; the electrical interface 115 is externally connected to a power supply and connected to the rotary excitation coil. The excitation coil is powered through the electrical interface 115. The current flowing in the excitation coil generates a magnetic field, causing the conductive particles in the fluid in the measuring inner tube 121 to cut the magnetic force lines, and thus inducing a voltage between the electrodes; By means of a rotary excitation coil capable of sliding between both ends of the outer sleeve 131, corresponding telescopic induction electrodes are pressed and triggered. When the rotary excitation coil is located at one end of the outer sleeve 131, the telescopic induction electrode at this end is pressed and triggered, and the telescopic induction electrode extends into the inner wall of the measuring inner tube 121 for measurement. When encountering situations such as detection of fluid stratification, fouling on the electrode surface, or turbulent flow of the detection fluid, only need to control the rotary excitation coil to slide to the other end of the outer sleeve 131, and at the same time press and trigger the telescopic induction electrode at the other end. Meanwhile, during the retraction process of the fouling electrode, the surface dirt is automatically peeled off, so as to achieve the effects of changing the detection positions of the excitation coil and the induction electrode, and cleaning the induction electrode, enabling it to flexibly cope with situations such as fluid stratification, fouling on the electrode surface, or turbulent flow of the detection fluid, and effectively improving the measurement accuracy of the electromagnetic flowmeter.

[0019] Example 2, as Figure 2 - Figure 7 and Figure 9 、 Figure 10 shown, an electromagnetic flowmeter includes Example 1. In addition, the sliding assembly includes a fixed ring 132, the fixed ring 132 is fixedly installed at both ends of the outer sleeve 131, deflection sliding grooves 133 are provided on both opposite sides of the outer sleeve 131, the deflection sliding grooves 133 are obliquely deflected by 90° along the outer wall of the measuring inner tube 121, a pair of oblique notch protrusions are provided on the side of the fixed ring 132 close to the outer sleeve 131, and the oblique notch protrusions on the fixed ring 132 are installed at both ends of the deflection sliding grooves 133 on the outer sleeve 131.

[0020] In the above embodiment, it should be noted that the oblique notch protrusions on the fixed ring 132 are inserted into both ends of the deflection sliding grooves 133 and fixed in the deflection sliding grooves 133. The oblique notch protrusions on the fixed ring 132 play a role in limiting the sliding of the rotary excitation coil. By means of the deflection sliding grooves 133 on the outer sleeve 131, the effect of limiting the sliding path of the rotary excitation coil is achieved. Cooperating with the deflection sliding grooves 133 that are obliquely deflected by 90°, the rotary excitation coil can slide horizontally and deflect by 90° along the surface of the measuring inner tube 121 at the same time.

[0021] Example 3, as Figure 2 - Figure 7 and Figure 9 - Figure 12As shown, an electromagnetic flowmeter includes Embodiment 2. In addition, the rotary excitation coil includes a coil seat 151. Two coil seats 151 are oppositely arranged on both sides of the outer sleeve 131. A deflection slider 156 is fixedly installed on the side of the coil seat 151 close to the outer sleeve 131. Oblique cuts are provided at both ends of the deflection slider 156. The deflection slider 156 is slidably installed in the deflection chute 133. The deflection slider 156 slides along the deflection chute 133. The rotary excitation coil includes a rotating clamping member 152. The rotating clamping member 152 is fixedly installed on one side of the coil seat 151. A propulsion ring 141 is installed on the side of the rotating clamping member 152 away from the coil seat 151. Openings are provided on the upper and lower opposite sides of the propulsion ring 141. A hydraulic rod 142 is fixedly installed on the outer wall of the connecting pipe 112 on the side of the propulsion ring 141 away from the rotating clamping member 152. The output end of the hydraulic rod 142 penetrates through the outer casing 111 and is fixedly connected to the propulsion ring 141. The rotary excitation coil includes an electromagnetic wire 153. The electromagnetic wire 153 is wound around the coil seat 151. A coil connector 154 is provided on the side of the coil seat 151 away from the outer sleeve 131. One end of the coil connector 154 penetrates through the coil seat 151 and is electrically connected to the electromagnetic wire 153. The other end of the coil connector 154 is connected to the coil wire 155. The end of the coil wire 155 away from the coil connector 154 extends upward into the processor housing 114 and is electrically connected to the electrical interface 115.

[0022] In the above embodiment, it should be noted that the propulsion ring 141 is rotatably installed on the rotating clamping member 152. The deflection slider 156 has a parallelogram structure. A plurality of hydraulic rods 142 are provided on the outer wall of the connecting pipe 112. The hydraulic rods 142 are externally connected to a power supply and a control system. Technicians observe the flow data output by the signal processor 175 through a display or a remote device. When abnormal conditions such as unstable flow, significant decrease or increase in the flow data occur, it can be judged that abnormal conditions such as fluid stratification, scale formation on the electrode surface, or detection of fluid turbulence may occur inside the flowmeter. At this time, technicians need to control the start of the hydraulic rods 142 to push the propulsion ring 141 to move. The propulsion ring 141 drives the rotating clamping member 152 and the coil seat 151 to move, so as to achieve the effect of driving the coil seat 151 to slide along the surface of the outer sleeve 131. At the same time, between the deflection slider 156 and the deflection chute 133, the coil seat 151 drives the rotating clamping member 152 and the propulsion ring 141 to deflect, and the coil seat 151 deflects by 90°; The electrical interface 115 conducts current through the coil wire 155 into the electromagnetic wire 153 through the coil connector 154. The current flowing in the electromagnetic wire 153 generates a magnetic field, so as to achieve the effect of causing the conductive particles in the fluid in the measuring inner tube 121 to cut the magnetic force lines; The width of the openings provided on the upper and lower opposite sides of the propulsion ring 141 is greater than the total width of the telescopic induction electrodes, so as to avoid the telescopic induction electrodes blocking the sliding of the propulsion ring 141.

[0023] Embodiment 4, as Figure 2 - Figure 7 and Figure 9 - Figure 12 As shown, an electromagnetic flowmeter includes embodiment 3. In addition, the rotary excitation coil includes a pressing slider 171, which is fixedly installed between the adjacent ends of two coil seats 151. The pressing slider 171 and the coil seats 151 form a ring structure. The pressing slider 171 is provided with convex plates on both sides close to the connecting pipe 112. The convex plates on both sides of the pressing slider 171 are tilted away from the outer sleeve 131. An induction connector 172 is fixedly installed in the middle of the pressing slider 171. The induction connector 172 passes through the pressing slider 171. One end of the induction connector 172 away from the surface of the outer sleeve 131 is electrically connected to a sensing wire 173. A processor interface 174 is provided at the bottom of the signal processor 175. One end of the sensing wire 173 away from the sensing connector 172 extends upward into the processor housing 114 and is electrically connected to the processor interface 174.

[0024] In the above embodiment, it should be noted that the pressing slider 171 is made of insulating material. When the coil base 151 moves and rotates, it will drive the pressing slider 171 to move and rotate. After the pressing slider 171 moves and rotates to a specified position, it can press down a specified telescopic sensing electrode. When the pressing slider 171 presses down the telescopic sensing electrode, the sensing connector 172 is connected to the telescopic sensing electrode. The voltage signal sensed by the telescopic sensing electrode is introduced into the processor interface 174 through the sensing connector 172 and the sensing wire 173, and then analyzed and output by the signal processor 175. An electrical signal proportional to the flow rate is output to achieve the effect of measuring the flow data in the inner tube 121.

[0025] Embodiment 5, as Figure 8 - Figure 16As shown, an electromagnetic flowmeter includes Embodiment 4. In addition, outer pipe openings 134 are provided on the upper and lower sides of one end of the outer jacket 111 close to the hydraulic rod 142, and outer pipe openings 134 are also provided on the lateral sides of the other end of the outer jacket 111 far from the hydraulic rod 142. Inner pipe openings 122 are provided at positions on the inner wall of the measuring inner pipe 121 close to the outer pipe openings 134. The telescopic induction electrode includes an electrode 163. Four electrodes 163 are respectively slidably inserted into the respective outer pipe openings 134 on the surface of the outer jacket 111. An airtight ring 161 is provided on one side of the outer pipe opening 134 close to the surface of the outer jacket 111. The airtight ring 161 is sleeved and installed on the outer side of the electrode 163. An air injection port is provided on one side of the airtight ring 161. Pressurized gas is injected into the airtight ring 161. Granular protrusions are provided on the surface of the airtight ring 161. The telescopic induction electrode includes an air ring bracket 162. The air ring bracket 162 is sleeved and arranged on the surface of the airtight ring 161 far from the outer jacket 111. The air ring bracket 162 is fixedly connected to the outer jacket 111. An electrode cap 164 is fixedly installed at one end of the electrode 163 far from the outer jacket 111. A spring 165 is provided between the electrode cap 164 and the air ring bracket 162. The spring 165 is installed on the outer wall of the electrode 163.

[0026] In the above embodiment, it should be noted that the spring 165 is sleeved on the outer wall of the electrode 163. When the electrode cap 164 contacts the induction joint 172, the electrode cap 164 is electrically connected to the induction joint 172. The airtight ring 161 is a hollow ring structure with a certain ductility. A large amount of gas is injected into the airtight ring 161 through the air injection port in advance, so that a high pressure is formed in the airtight ring 161. In the initial state, the elastic force of the spring 165 itself is used to push the electrode cap 164 to drive the electrode 163 to jack up. At this time, the lower end of the electrode 163 is disengaged from the center of the airtight ring 161. Under the limit of the air ring bracket 162, the high-pressure gas in the airtight ring 161 causes the airtight ring 161 to squeeze into the outer pipe opening 134 to achieve the effect of sealing the outer pipe opening 134. When the pressing slider 171 is moved above the electrode cap 164, under the extrusion of the electrode cap 164, the electrode cap 164 pushes the electrode 163 to insert into the center of the airtight ring 161 and pass through the outer pipe opening 134 and the inner pipe opening 122. The lower end of the electrode 163 extends into the inner wall of the measuring inner pipe 121. At the same time, the electrode cap 164 is in contact connection with the induction joint 172, and the spring 165 is stressed and contracts. At this time, the airtight ring 161 still plays a sealing role between the electrode 163 and the inner pipe opening 122. When the pressing slider 171 is moved away again, the spring 165 pushes the electrode cap 164 to drive the electrode 163 to retract again. Through the granular protrusions on the surface of the airtight ring 161, the effect of rubbing the end of the electrode 163 to make the scale on its surface fall off is achieved.

[0027] The usage process of the present invention is as follows: Those skilled in the art connect the electrical interface 115 to a power source. The electrical interface 115 conducts the current through the coil wire 155 to the coil joint 154 and then into the electromagnetic wire 153. The flowing current in the electromagnetic wire 153 generates a magnetic field, causing the conductive particles in the fluid within the measurement inner tube 121 to cut the magnetic force lines. At this time, the inner wall electrodes 163 of the measurement inner tube 121 sense the fluid voltage, and the voltage signal is conducted through the electrode cap 164, the induction joint 172, and the induction wire 173 to the processor interface 174, and then analyzed by the signal processor 175 to output an electrical signal proportional to the flow rate. Then, through the built-in remote signal transmission module of the signal processor 175, the flow rate data is sent to a remote display device, and technicians can observe the flow rate data through the remote device display. When abnormal conditions such as unstable flow rate, significant decrease or increase in the flow rate data occur, it can be determined that abnormal conditions such as fluid stratification, scale formation on the electrode surface, or detection of fluid turbulence may occur inside the flowmeter. At this time, technicians need to control and start the hydraulic rod 142 to push the propulsion ring 141 to move. The propulsion ring 141 drives the rotating fixture 152 and the coil seat 151 to move, driving the coil seat 151 to slide along the surface of the outer sleeve 131. At the same time, between the deflection slider 156 and the deflection chute 133, a deflection occurs between the coil seat 151, the rotating fixture 152, and the propulsion ring 141. The coil seat 151 deflects 90°, and at the same time drives the pressing slider 171 to deflect 90° to above the electrode 163 at the other end. When the pressing slider 171 moves above the electrode cap 164, under the extrusion of the electrode cap 164, the electrode cap 164 pushes the electrode 163 to insert into the center of the airtight ring 161 and pass through the outer tube opening 134 and the inner tube opening 122. The lower end of the electrode 163 extends into the inner wall of the measurement inner tube 121. At the same time, the electrode cap 164 is in contact connection with the induction joint 172 to switch the detection positions of the excitation coil and the induction electrode.

[0028] The above are only the preferred embodiments of the present invention. Any person skilled in the art may modify the present invention by using the technical solutions described above or modify it into an equivalent technical solution. Therefore, any simple modification or equivalent replacement made according to the technical solutions of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. An electromagnetic flowmeter, comprising a flowmeter housing and a switchable inductive core, characterized in that: The flow meter housing comprises an outer shell, connecting pipes are installed at both ends of the outer shell, a flange is installed at one end of the connecting pipe away from the outer shell, a processor housing is installed on the top surface of the outer shell, an electrical interface is provided on the processor housing, a signal processor is installed in the processor housing, and bolts are installed between the outer shell and the processor housing; The switchable induction core comprises a measuring inner tube, which is mounted on the inner side of the outer shell, which is mounted on the inner side of the connecting tube, and the outer wall of the measuring inner tube fits the inner wall of the connecting tube. A sliding component is mounted on the outer wall of the measuring inner tube, which comprises an outer sleeve, which is fixedly mounted on the outer wall of the measuring inner tube, and a pair of telescopic induction electrodes are respectively arranged at both ends of the outer wall of the outer sleeve. The sliding component comprises a fixing ring, which is fixedly mounted on both ends of the outer sleeve, and deflection grooves are arranged on opposite sides of the outer sleeve, and the deflection grooves are obliquely deflected 90° along the outer wall of the measuring inner tube. A pair of oblique cut protrusions are arranged on one side of the fixing ring close to the outer sleeve, and the oblique cut protrusions on the fixing ring are mounted on both ends of the deflection grooves on the outer sleeve. A rotating protrusion is slidably mounted on the outer wall of the outer sleeve. A rotary excitation coil, which is used to slide on both ends of the outer sleeve and press to trigger the corresponding telescopic induction electrodes. The rotary excitation coil includes a coil seat, and the two coil seats are relatively arranged on both sides of the outer sleeve. A deflection slider is fixedly installed on the side of the coil seat close to the outer sleeve, and oblique cuts are arranged at both ends of the deflection slider. The deflection slider is slidably installed in the deflection slide groove, and the deflection slider slides along the deflection slide groove. The rotary excitation coil includes a rotating clamp, which is fixedly installed on one side of the coil seat, and a propulsion ring is installed on the side of the rotating clamp away from the coil seat, and openings are arranged on the upper and lower sides of the propulsion ring. A hydraulic rod is fixedly installed on the outer wall of the connecting tube of the propulsion ring away from the rotating clamp, and the output end of the hydraulic rod passes through the outer shell and is fixedly connected to the propulsion ring.

2. An electromagnetic flowmeter according to claim 1, characterized in that: The rotary excitation coil includes an electromagnetic wire, which is wound on a coil seat. A coil connector is provided on the side of the coil seat away from the outer sleeve. One end of the coil connector passes through the coil seat and is electrically connected to the electromagnetic wire, and the other end of the coil connector is connected to the coil wire. One end of the coil wire away from the coil connector extends upward into the processor housing and is electrically connected to the electrical interface.

3. An electromagnetic flowmeter according to claim 2, characterized in that: The rotary excitation coil includes a pressing slider, which is fixedly installed between the adjacent ends of two coil seats. The pressing slider and the coil seat form an annular structure. The pressing slider is provided with convex plates on both sides close to the connecting tube, and the convex plates on both sides of the pressing slider are tilted in the direction away from the outer sleeve.

4. An electromagnetic flowmeter according to claim 3, characterized in that: A sensing joint is fixedly installed in the middle of the pressing slider. The sensing joint penetrates through the pressing slider. One end of the sensing joint away from the surface of the outer sleeve is electrically connected to a sensing wire. A processor interface is provided at the bottom of the signal processor. One end of the sensing wire away from the sensing joint extends upward into the processor housing and is electrically connected to the processor interface.

5. An electromagnetic flowmeter according to claim 4, characterized in that: Outer tube openings are provided on the upper and lower sides of the outer shell near one end of the hydraulic rod, and outer tube openings are also provided on the transverse sides of the outer shell away from one end of the hydraulic rod. Inner tube openings are provided at positions on the inner wall of the measuring inner tube close to the outer tube openings.

6. An electromagnetic flowmeter according to claim 5, characterized in that: The telescopic induction electrode includes an electrode. Four electrodes are respectively slidably inserted into the respective outer tube openings on the surface of the outer shell. An airtight ring is provided on one side of the outer tube opening close to the surface of the outer shell. The airtight ring is sleeved outside the electrode. An air injection port is provided on one side of the airtight ring. Pressurized gas is injected into the airtight ring. Granular protrusions are provided on the surface of the airtight ring.

7. An electromagnetic flowmeter according to claim 6, characterized in that: The telescopic induction electrode includes an air ring bracket. The air ring bracket is sleeved on the surface of the airtight ring away from the outer shell. The air ring bracket is fixedly connected to the outer shell. An electrode cap is fixedly installed at one end of the electrode away from the outer shell. A spring is provided between the electrode cap and the air ring bracket. The spring is installed on the outer wall of the electrode.

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