Electromagnetic flowmeter

Abstract

The invention provides an electromagnetic flowmeter which comprises a measuring electrode (100), a measuring pipeline (10), a lining (20), a grounding electrode (30), a pressure sensitive element (40), a temperature sensor (50) and a processor unit (60). The grounding electrode has thermal conductivity and electrical conductivity, the grounding electrode is arranged in the measuring pipeline and the lining in a penetrating mode, and the pressure sensitive element is arranged in an installation hole (31) in the grounding electrode. The temperature sensor is arranged on the grounding electrode and located outside the measuring pipeline. The processor unit is configured to receive the electric signal of the measuring electrode, calculate the flow of the fluid in the lining and receive the measurement results of the pressure sensitive element and the temperature sensor. The processor unit is further configured to calculate the temperature of the fluid in the lining according to the measurement result of the temperature sensor. The electromagnetic flowmeter has the functions of measuring flow, pressure and temperature, the cost is lower, and the risk of pipeline leakage is reduced.

Description

Technical Field

[0001] The invention relates to a flow meter, in particular to an electromagnetic flow meter capable of measuring flow, pressure and temperature simultaneously. Background Art

[0002] An electromagnetic flowmeter is an instrument that uses the principle of electromagnetic induction to measure the flow rate of a conductive fluid based on the electromotive force induced when the conductive fluid passes through an external magnetic field. In actual usage scenarios, in addition to measuring the flow rate with the help of an electromagnetic flowmeter, customers often need to measure the pressure and temperature of the fluid in the pipeline. In order to achieve the above functions, customers need to connect three independent devices, namely an electromagnetic flowmeter, a pressure sensor, and a temperature sensor, to the pipeline, which increases the risk of pipeline leakage. In addition, the three independent devices need to be connected to the power supply and signal lines respectively and installed, debugged, and maintained, which increases the cost of use. Summary of the invention

[0003] The object of the present invention is to provide an electromagnetic flowmeter having the functions of measuring flow, pressure and temperature, with lower cost and reduced risk of pipeline leakage.

[0004] The invention provides an electromagnetic flowmeter, comprising a measuring pipeline, an inner lining, a grounding electrode, a pressure sensitive element, a temperature sensor and a processor unit. A first through hole is formed on the measuring pipeline; the liner is penetrated in the measuring pipeline, the measuring electrode is arranged on the inner surface of the liner, and a second through hole opposite to the first through hole is formed on the liner; the grounding electrode has thermal conductivity and electrical conductivity, the grounding electrode is penetrated in the first through hole and the second through hole, a mounting hole is formed on the grounding electrode, the mounting hole is connected to the interior of the liner, a diaphragm is arranged in the mounting hole, the diaphragm is separated in the mounting hole to form a sealed cavity, the sealed cavity is filled with an insulator, and the diaphragm can be deformed according to the pressure inside the liner; a pressure sensitive element is arranged in the sealed cavity, the pressure sensitive element can measure the pressure inside the liner according to the deformation of the diaphragm; a temperature sensor is arranged on the grounding electrode, and the temperature sensor can measure the temperature of the grounding electrode; a processor unit is connected to the measuring electrode, the grounding electrode, the pressure sensitive element and the temperature sensor, the processor unit is configured to receive the electrical signal of the measuring electrode and calculate the flow rate of the fluid inside the liner, the processor unit is also configured to be able to receive the measurement results of the pressure sensitive element and the temperature sensor, and the processor unit is also configured to be able to calculate the temperature of the fluid inside the liner according to the measurement results of the temperature sensor.

[0005] The electromagnetic flowmeter provided by the present invention has only one access point, which is a ground electrode. By arranging a pressure sensitive element and a temperature sensor on the ground electrode, the function of measuring pressure and temperature in addition to measuring flow is also realized, which has lower cost and reduces the risk of pipeline leakage.

[0006] In another exemplary embodiment of the electromagnetic flowmeter, the electromagnetic flowmeter further includes a first fixing member and a second fixing member. The first fixing member can be fixed to the portion of the grounding electrode extending into the inner liner; the second fixing member can be connected to the portion of the grounding electrode located outside the inner liner, and cooperate with the first fixing member to fix the grounding electrode in the second through hole of the inner liner. The above structure is simple and has a lower manufacturing cost.

[0007] In another exemplary embodiment of the electromagnetic flowmeter, the first fixing member and the housing of the grounding electrode are designed as separate parts, or the first fixing member and the housing of the grounding electrode are integrally formed and form an inverted T-shaped structure with the housing of the grounding electrode. The separate design of the first fixing member and the grounding electrode is more convenient for assembly, while the integral forming can reduce the manufacturing cost.

[0008] In another exemplary embodiment of the electromagnetic flowmeter, the liner can produce elastic deformation, and a sealing portion extending toward the inside of the liner is formed on the first fixing member, and the sealing portion can be embedded in the liner at the periphery of the second through hole to seal the second through hole. In this way, the sealing of the electromagnetic flowmeter can be ensured without an additional sealing structure, thereby reducing the manufacturing cost.

[0009] In another exemplary embodiment of the electromagnetic flowmeter, the first fixing member is integrally formed with the housing of the grounding electrode, the second through hole is in the shape of a truncated cone, and the diameter of the end of the second through hole connected to the inside of the liner is larger than the diameter of the end connected to the outside of the liner, and a truncated cone side surface corresponding to the shape of the second through hole is formed on the first fixing member, and the truncated cone side surface can fit the inner surface of the second through hole to seal the second through hole. In this way, the sealing of the electromagnetic flowmeter can be ensured without an additional sealing structure, reducing the manufacturing cost.

[0010] In another exemplary embodiment of the electromagnetic flowmeter, the measuring pipe and the inner liner are arranged at intervals, and an insulating material is filled between the measuring pipe and the inner liner, thereby ensuring the thermal insulation and sealing of the electromagnetic flowmeter, and further ensuring the accuracy of temperature measurement and pressure measurement.

[0011] In another exemplary embodiment of the electromagnetic flowmeter, the processor unit is further configured to generate a first alarm signal when the calculated flow rate of the fluid inside the liner is 0 and the measurement result of the pressure sensitive element is 0. The electromagnetic flowmeter thereby realizes an alarm function when the fluid level in the pipeline is low.

[0012] In another exemplary embodiment of the electromagnetic flowmeter, the processor unit is further configured to generate a second alarm signal when the calculated flow rate of the fluid inside the liner is greater than 0 and the measurement result of the pressure sensitive element is 0. This implements an alarm function when the fluid in the pipeline is not full.

[0013] In another exemplary embodiment of the electromagnetic flowmeter, the processor unit is further configured to record the pressure value measured by the pressure sensitive element at each preset time interval within a measurement time period, save it as a real-time pressure value, divide the difference between two adjacent real-time pressure values ​​at each time by the preset time, save the result as a real-time change rate, compare each real-time change rate with the preset change rate, count the number of real-time change rates that are less than the preset change rate within the measurement time period, save the result as the number of abnormalities, and when the number of abnormalities is greater than a preset number, the processor unit generates a third alarm signal. This realizes the alarm function when there are excessive bubbles in the fluid in the pipeline.

[0014] In another exemplary embodiment of the electromagnetic flowmeter, the electromagnetic flowmeter further includes a mounting base and a cable. The mounting base is cylindrical and is mounted on the top of the measuring pipe. One end of the mounting base is connected to the first through hole, and the other end opposite is used to mount the processor unit. The interior of the mounting base is filled with insulating and heat-insulating materials. The cable is passed through the mounting base, one end of the cable is connected to the pressure sensitive element, and the other end extends out of the mounting base and is used to connect to the atmospheric pressure reference point. In this way, the temperature sensor can be isolated from the external environment, thereby improving the measurement accuracy and sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following drawings are only used to schematically illustrate and explain the present invention, and do not limit the scope of the present invention.

[0016] Figure 1 The figure is a cross-sectional structural diagram of a schematic implementation of an electromagnetic flowmeter.

[0017] Figure 2 This is an enlarged cross-sectional view of the electromagnetic flowmeter.

[0018] Figure 3 The figure is a structural block diagram of a schematic implementation of an electromagnetic flowmeter.

[0019] Figure 4 It is an enlarged cross-sectional view of another schematic embodiment of the electromagnetic flowmeter.

[0020] Figure 5 It is an enlarged cross-sectional view of another schematic embodiment of the electromagnetic flowmeter.

[0021] Figure 6 It is a cross-sectional structural diagram of another schematic implementation of an electromagnetic flowmeter.

[0022] Description of symbols

[0023] 10 Measuring pipeline

[0024] 11 First through hole

[0025] 20 Lining

[0026] 21 Second through hole

[0027] 30 Grounding electrode

[0028] 31 Mounting holes

[0029] 311 Diaphragm

[0030] 312 Sealed Chamber

[0031] 40 Pressure sensitive element

[0032] 50 Temperature Sensor

[0033] 60 Processor Units

[0034] 71 First fixing piece

[0035] 711 Seal

[0036] 712 Round table side

[0037] 72 Second fixing member

[0038] 73 elastic gasket

[0039] 74 Gasket

[0040] 80 Mounting Base

[0041] 90 Cable

[0042] 100 Measuring electrodes DETAILED DESCRIPTION

[0043] In order to have a clearer understanding of the technical features, purposes and effects of the invention, the specific embodiments of the present invention are now described with reference to the accompanying drawings. The same reference numerals in the drawings represent components with the same structure or similar structures but the same functions.

[0044] In this document, “exemplary” means “serving as an example, instance or illustration”, and any diagram or implementation described in this document as “exemplary” should not be interpreted as a more preferred or more advantageous technical solution.

[0045] In this article, "first", "second", etc. do not indicate their importance or order, but are only used to indicate the difference between each other for the convenience of document description.

[0046] In order to simplify the drawings, each figure only schematically shows the parts related to the present invention, which do not represent the actual structure of the product.

[0047] Figure 1 The figure is a cross-sectional structural diagram of a schematic implementation of an electromagnetic flowmeter. Figure 2 This is an enlarged cross-sectional view of the electromagnetic flowmeter. Figure 1 and Figure 2 The electromagnetic flow meter includes a measuring electrode 100 , a measuring pipe 10 , a liner 20 , a grounding electrode 30 , a pressure sensitive element 40 , a temperature sensor 50 and a processor unit 60 .

[0048] The measuring pipe 10 is used for fluid to pass through, and a first through hole 11 is formed thereon. The liner 20 is arranged through the measuring pipe 10 and directly contacts the fluid, and is used to increase the corrosion resistance of the measuring pipe 10 and prevent the induced potential from being short-circuited by the measuring pipe 10. The measuring electrode 100 is arranged on the inner surface of the liner 20, and a second through hole 21 opposite to the first through hole 11 is formed on the liner 20.

[0049] The grounding electrode 30 has thermal conductivity and electrical conductivity. The grounding electrode 30 is inserted into the first through hole 11 and the second through hole 21. A mounting hole 31 is formed on the grounding electrode 30. The mounting hole 31 communicates with the interior of the liner 20. A stainless steel diaphragm 311 is disposed in the mounting hole 31. The diaphragm 311 is separated in the mounting hole 31 to form a sealed cavity 312. The sealed cavity 312 is filled with an insulating liquid such as silicone oil. The diaphragm 311 can be deformed according to the pressure inside the liner 20. The pressure sensitive element is disposed in the sealed cavity 312. When the electromagnetic flowmeter is in use, Figure 1 As shown, in most working conditions, the ground electrode 30 is located at the top of the measuring pipe 10, and the pressure sensitive element 40 can measure the pressure inside the liner 20 according to the deformation of the diaphragm 311. The temperature sensor 50 is arranged on the ground electrode 30 and is located outside the measuring pipe 10. The temperature sensor 50 can measure the temperature of the ground electrode 30.

[0050] Figure 3 FIG. 1 is a block diagram of a schematic implementation of an electromagnetic flowmeter. Figure 3 The processor unit 60 is connected to the measuring electrode 100, the pressure sensitive element 40 and the temperature sensor 50. The processor unit 60 is configured to receive the electrical signal of the measuring electrode 100 and calculate the flow rate of the fluid inside the liner 20. The processor unit 60 is also configured to receive the measurement results of the pressure sensitive element 40 and the temperature sensor 50.

[0051] The processor unit 60 is also configured to calculate the temperature of the fluid inside the liner 20 according to the measurement results of the temperature sensor 50 according to the pre-stored temperature comparison table. The temperature comparison table includes the temperature of the fluid inside the liner 20 corresponding to each temperature of the ground electrode 30. The temperature comparison table needs to be obtained according to the actual use scenario experiment, for example, the liner 20 is filled with fluid, and then the fluid is accurately heated by the heating system, and the measurement results of the temperature sensor 50 are recorded to generate the temperature comparison table.

[0052] The electromagnetic flowmeter provided by the present invention only has a ground electrode 30 access point. By arranging a pressure sensitive element 40 and a temperature sensor 50 on the ground electrode 30, the function of measuring pressure and temperature in addition to measuring flow is also achieved, which has lower costs and reduces the risk of pipeline leakage.

[0053] In an exemplary embodiment, referring to Figure 1 , the electromagnetic flowmeter also includes a mounting base 80 and a cable 90. The mounting base 80 is cylindrical and is installed on the top of the measuring pipe 10. One end of the mounting base 80 is connected to the first through hole 11, and the other end is used to install the processor unit 60. The interior of the mounting base 80 is filled with insulating and heat-insulating materials. The cable 90 is passed through the mounting base 80, one end of the cable 90 is connected to the pressure sensitive element 40, and the other end extends out of the mounting base 80 and is used to connect to the atmospheric pressure reference point. In this way, the temperature sensor 50 can be isolated from the external environment, thereby improving the measurement accuracy. At the same time, the mounting base 80 can also improve the sealing of the electromagnetic flowmeter.

[0054] In the exemplary embodiment, the processor unit 60 is further configured to generate a first alarm signal when the calculated flow rate of the fluid inside the liner 20 is 0 and the measurement result of the pressure sensitive element 40 is 0. Since the ground electrode 30 is located at the top of the measuring pipe 10, when the processor unit 60 calculates that the flow rate of the fluid inside the liner 20 is 0 and the measurement result of the pressure sensitive element 40 is 0, it indicates that the fluid level in the pipeline is lower than the measuring electrode 100, and the electromagnetic flowmeter thereby realizes the alarm function when the fluid level in the pipeline is low.

[0055] In the exemplary embodiment, the processor unit 60 is further configured to generate a second alarm signal when the calculated flow rate of the fluid inside the liner 20 is greater than 0 and the measurement result of the pressure sensitive element 40 is 0. Since the ground electrode 30 is located at the top of the measuring pipe 10, when the processor unit 60 calculates that the flow rate of the fluid inside the liner 20 is greater than 0 and the measurement result of the pressure sensitive element 40 is 0, it means that the fluid level in the pipeline is higher than the measuring electrode 100, but the measuring pipe 10 is not filled. In this way, an alarm function is realized when the fluid in the pipeline is not full.

[0056] The processor unit 60 is also configured to record the pressure value measured by the pressure sensitive element 40 at each preset time interval within a measurement time period, save it as a real-time pressure value, divide the difference between two adjacent real-time pressure values ​​at each time by the preset time, save the result as a real-time change rate, compare each real-time change rate with the preset change rate, count the number of real-time change rates that are less than the preset change rate within the measurement time period, save the result as the number of abnormal times, and when the number of abnormal times is greater than a preset number, the processor unit 60 generates a third alarm signal. This realizes the alarm function when there are excessive bubbles in the fluid in the pipeline. In this exemplary embodiment, the processor unit 60 specifically makes a judgment through the following formula:

[0057] ;

[0058] ;

[0059] ;

[0060] ;

[0061] in, Indicates the real-time pressure value. Indicates the preset time. Indicates the preset rate of change, Indicates the number of exceptions. Indicates the total number of real-time pressure values.

[0062] In actual use scenarios, based on the positional relationship between the electromagnetic flowmeter and the delivery pump and the performance of the delivery pump, the real-time rate of change of the fluid pressure should be kept at a fixed value, that is, the preset rate of change. If excessive bubbles appear in the fluid, the absolute value of the average rate of change of the fluid pressure will fluctuate, resulting in a situation where it is less than the preset rate of change. Set to , however, it is not limited thereto, in other exemplary embodiments, The value needs to be determined based on the positional relationship between the electromagnetic flowmeter and the delivery pump and the performance of the delivery pump.

[0063] In the exemplary embodiment, the preset number is set to achieve the effect of controlling the alarm sensitivity. Increasing the preset number can reduce the alarm sensitivity and prevent frequent alarms, while reducing the preset number can increase the alarm sensitivity and prevent missed alarms. However, it is not limited thereto. In other exemplary implementations, it is necessary to adjust the preset number of times according to actual needs, that is, adjust the value of N in the formula.

[0064] In an exemplary embodiment, referring to Figure 2, the electromagnetic flowmeter also includes a first fixing member 71 and a second fixing member 72. The first fixing member 71 can be fixed to the portion of the grounding electrode 30 extending into the interior of the liner 20. In the exemplary embodiment, the first fixing member 71 and the grounding electrode 30 are an integral structure, and form an inverted T-shaped structure with the outer shell of the grounding electrode 30, thereby facilitating processing and manufacturing. The second fixing member 72 can be threadedly connected to the portion of the grounding electrode 30 located outside the liner 20, and the second fixing member 72 can cooperate with the first fixing member 71 to clamp the two sides of the liner 20, and fix the grounding electrode 30 in the second through hole 21 of the liner 20. The above structure is simple and has lower manufacturing cost.

[0065] In an exemplary embodiment, referring to Figure 2 The electromagnetic flowmeter further comprises an elastic gasket 73 and a gasket 74, which are sleeved on the ground electrode 30 and located between the second fixing member 72 and the liner 20. In this way, the ground electrode 30 is firmly installed.

[0066] In an exemplary embodiment, referring to Figure 2 The liner 20 can produce elastic deformation, such as a rubber liner. A sealing portion 711 extending toward the inside of the liner is formed on the first fixing member 71. The first fixing member 71 and the second fixing member 72 clamp the liner 20 so that the sealing portion 711 can be embedded in the inside of the liner 20, and the sealing portion 711 can seal the second through hole 21 at the periphery of the second through hole 21 in cooperation with the elastic restoring force of the liner 20. In this way, the sealing performance of the electromagnetic flowmeter can be ensured without an additional sealing structure, thereby reducing the manufacturing cost.

[0067] Figure 4 FIG. 1 is an enlarged cross-sectional view of another exemplary embodiment of an electromagnetic flowmeter. Figure 4 , and Figure 3 The same or similar points of the electromagnetic flowmeter in the embodiment are not described in detail. The difference is that the liner 20 is almost unable to deform, or cannot return to its original shape after deformation, such as a polytetrafluoroethylene liner. The second through hole 21 is in the shape of a truncated cone, and the diameter of the end of the second through hole 21 connected to the inside of the liner 20 is larger than the diameter of the end connected to the outside of the liner 20. A truncated cone side 712 corresponding to the shape of the second through hole 21 is formed on the first fixing member 71. The first fixing member 71 and the second fixing member 72 clamp the liner 20 so that the truncated cone side 712 can fit the inner surface of the second through hole 21 to seal the second through hole 21. The force-bearing surface between the truncated cone side 712 and the second through hole 21 is relatively large, and the inner surface of the second through hole 21 is uniformly shaped, which can achieve a sealing effect while also preventing the liner 20 made of a material similar to polytetrafluoroethylene from being damaged or cracked. In this way, the sealing of the electromagnetic flowmeter can be ensured without the need for an additional sealing structure, thereby reducing the manufacturing cost.

[0068] Figure 5FIG. 1 is an enlarged cross-sectional view of another exemplary embodiment of an electromagnetic flowmeter. Figure 5 , and Figure 3 The same or similar parts of the electromagnetic flowmeter in the embodiment are not described in detail, and the difference is that the first fixing member 71 and the housing of the grounding electrode 30 are designed as separate parts, and the first fixing member 71 can be threadedly connected to the part of the grounding electrode 30 extending into the inner part of the liner 20. When installing the grounding electrode 30, the first fixing member 71 can be separated, and the grounding electrode 30 can be installed from the inside or outside of the measuring pipe 10. After the grounding electrode 30 is installed in place, the first fixing member 71 is threadedly connected, which is more convenient for operation.

[0069] Figure 6 FIG. 4 is a cross-sectional structural diagram of another exemplary embodiment of an electromagnetic flowmeter. Figure 6 , and Figure 1 The same or similar aspects of the electromagnetic flowmeter in the embodiment are not described in detail, and the difference is that the measuring pipe 10 and the liner 20 are arranged at intervals, and an insulating material is filled between the measuring pipe 10 and the liner 20. This ensures the thermal insulation and sealing of the electromagnetic flowmeter, and further ensures the accuracy of temperature measurement and pressure measurement.

[0070] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0071] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation scheme or changes that do not deviate from the technical spirit of the present invention, such as combination, division or repetition of features, should be included in the scope of protection of the present invention.

Claims

1. An electromagnetic flowmeter, comprising a measuring electrode (100), characterized in that The electromagnetic flowmeter comprises: A measuring pipe (10) having a first through hole (11) formed therein; An inner liner (20) is inserted into the measuring pipe (10), the measuring electrode (100) is arranged on the inner surface of the inner liner (20), and a second through hole (21) opposite to the first through hole (11) is formed on the inner liner (20); A grounding electrode (30) having thermal conductivity and electrical conductivity, the grounding electrode (30) being inserted through the first through hole (11) and the second through hole (21), the grounding electrode (30) being formed with a mounting hole (31), the mounting hole (31) being in communication with the interior of the liner (20), a diaphragm (311) being arranged in the mounting hole (31), the diaphragm (311) being separated in the mounting hole (31) to form a sealed cavity (312), the sealed cavity (312) being filled with an insulator, and the diaphragm (311) being capable of deforming according to the pressure inside the liner; a pressure sensitive element (40) disposed in the sealed cavity (312), the pressure sensitive element (40) being capable of measuring the pressure inside the liner (20) according to the deformation of the diaphragm (311); a temperature sensor (50), which is disposed on the ground electrode (30), and the temperature sensor (50) is capable of measuring the temperature of the ground electrode (30); and A processor unit (60) is connected to the measuring electrode (100), the grounding electrode (30), the pressure sensitive element (40) and the temperature sensor (50); the processor unit (60) is configured to receive the electrical signal of the measuring electrode (100) and calculate the flow rate of the fluid inside the liner (20); the processor unit (60) is also configured to be able to receive the measurement results of the pressure sensitive element (40) and the temperature sensor (50); the processor unit (60) is also configured to be able to calculate the temperature of the fluid inside the liner (20) based on the measurement results of the temperature sensor (50).

2. The electromagnetic flowmeter according to claim 1, characterized in that: The electromagnetic flowmeter also includes: A first fixing member (71) capable of being fixed to a portion of the ground electrode (30) extending into the interior of the liner (20); and A second fixing member (72) is connectable to a portion of the grounding electrode (30) located outside the inner liner (20), and cooperates with the first fixing member (71) to fix the grounding electrode (30) in a second through hole (21) of the inner liner (20).

3. The electromagnetic flowmeter according to claim 2, characterized in that: The first fixing member (71) and the outer shell of the grounding electrode (30) are of separate designs, or the first fixing member (71) and the outer shell of the grounding electrode (30) are integrally formed and form an inverted T-shaped structure with the outer shell of the grounding electrode (30).

4. The electromagnetic flowmeter according to claim 3, characterized in that: The liner (20) is capable of elastic deformation, and a sealing portion (711) extending toward the interior of the liner is formed on the first fixing member (71), and the sealing portion (711) is capable of being embedded in the liner (20) at the periphery of the second through hole (21) to seal the second through hole (21).

5. The electromagnetic flowmeter according to claim 3, characterized in that: The first fixing member (71) is integrally formed with the outer shell of the grounding electrode (30); the second through hole (21) is in the shape of a truncated cone, and the diameter of one end of the second through hole (21) connected to the interior of the liner (20) is larger than the diameter of one end connected to the exterior of the liner (20); a truncated cone side surface (712) corresponding to the shape of the second through hole (21) is formed on the first fixing member (71); the truncated cone side surface (712) is capable of fitting against the inner surface of the second through hole (21) to seal the second through hole (21).

6. The electromagnetic flowmeter according to claim 1, characterized in that: The measuring pipe (10) and the inner liner (20) are arranged at an interval, and an insulating material is filled between the measuring pipe (10) and the inner liner (20).

7. The electromagnetic flowmeter according to claim 1, characterized in that: The processor unit (60) is also configured to generate a first alarm signal when the flow rate of the fluid inside the liner (20) is calculated to be 0 and the measurement result of the pressure sensitive element (40) is 0.

8. The electromagnetic flowmeter according to claim 1, characterized in that: The processor unit (60) is also configured to generate a second alarm signal when the calculated flow rate of the fluid inside the liner (20) is greater than 0 and the measurement result of the pressure sensitive element (40) is 0.

9. The electromagnetic flowmeter according to claim 1, characterized in that: The processor unit (60) is further configured to record the pressure value measured by the pressure sensitive element (40) at intervals of a preset time within a measurement time period, save the value as a real-time pressure value, divide the difference between two adjacent real-time pressure values ​​at each time by the preset time, save the result as a real-time change rate, compare each real-time change rate with a preset change rate, count the number of real-time change rates that are less than the preset change rate within the measurement time period, save the result as an abnormal number, and when the abnormal number is greater than a preset number, the processor unit (60) generates a third alarm signal.

10. The electromagnetic flowmeter according to claim 1, characterized in that: The electromagnetic flowmeter also includes: a mounting base (80) which is cylindrical and mounted on the top of the measuring pipe (10); one end of the mounting base (80) is in communication with the first through hole (11); the other end opposite thereto is used for mounting the processor unit (60); the interior of the mounting base (80) is filled with insulating and heat-insulating material; and A cable (90) is passed through the mounting base (80), one end of the cable (90) is connected to the pressure sensitive element (40), and the other end extends out of the mounting base (80) and is used to connect to an atmospheric pressure reference point.

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