Non-contact lorentz force flowmeter and method for high temperature liquid metals

Abstract

The application discloses a non-contact Lorentz force flowmeter and method suitable for high-temperature liquid metal, which comprises an electromagnetic coil, an iron core, a force sensor, a transmitter and a coil excitation power source; the electromagnetic coil is arranged on both sides of a pipeline to be measured and wound on the magnetically conductive iron core; the iron core is fixed on a force measuring support; the force measuring support is in contact with the force sensor, and the force sensor is connected with the transmitter; the electromagnetic coil is connected with the coil excitation power source; the pipeline to be measured is horizontally or vertically placed, and the liquid metal flows in the pipeline to be measured along the horizontal or vertical direction; the outer wall of the pipeline to be measured is wrapped with a high-temperature-resistant heat insulation layer; an external magnet is generated through the electromagnetic coil, and the magnetic lines generated by the external magnet cannot be parallel to the flow direction of the liquid metal; the Lorentz force generated by the interaction between the liquid metal flowing in the pipeline to be measured and the external magnet is directly measured by the force sensor, so that the liquid metal flow measurement in the pipeline to be measured is realized. The flowmeter measuring component does not contact the high-temperature liquid metal, and does not need to be connected into the pipeline to be measured.

Description

Technical Field

[0001] This invention relates to the field of flow meter technology, and more specifically to a non-contact Lorentz force flow meter and method applicable to high-temperature liquid metals. Background Technology

[0002] Liquid metals possess excellent thermal conductivity and heat-carrying capacity, making them widely used in the nuclear industry. For example, liquid sodium is used as a cooling medium in the primary loop of fast reactors; lead-based liquid metals such as lead-bismuth are also widely used in Generation IV nuclear reactors; liquid lithium or lithium-lead alloys are used as tritium breeders in fusion reactors, and also as coolants, to design high-thermal-efficiency fusion reactors. To improve the thermoelectric conversion efficiency and economic competitiveness of these reactors, the operating temperature of liquid metals is relatively high (up to 800℃). However, high-temperature liquid metals are highly corrosive, making flow measurement extremely difficult. Furthermore, the metallurgical industry also faces the problem of high-temperature liquid metal flow, such as the transportation of molten aluminum, where flow measurement also presents significant challenges.

[0003] Currently, widely used flow meters typically employ contact measurement methods, requiring the measuring component to be connected to existing pipelines via flanges, with the measuring component in contact with the fluid. Examples include commonly used differential pressure flow meters, electromagnetic flow meters, and vortex flow meters. Ultrasonic flow meters can use non-contact measurement methods, but their ultrasonic probes need to contact the outer wall of the pipe, therefore their operating temperature is generally limited to 200℃. Due to the strong corrosiveness of high-temperature liquid metals, contact flow meters suffer from severe probe corrosion during long-term operation, ultimately affecting measurement accuracy. Furthermore, high temperatures present limitations in material usage and difficulties in sealing flange interfaces, making the aforementioned flow meters unsuitable for measuring the flow of high-temperature liquid metals. Flow rate is a crucial operating parameter in the nuclear energy and metallurgical industries, closely related to the safe operation of equipment and facilities.

[0004] Therefore, in order to meet the needs of high-temperature liquid metal flow measurement and monitoring in the nuclear energy and metallurgical industries, there is an urgent need to develop a non-contact flow meter that is resistant to high temperatures and not corroded by liquid metal. Summary of the Invention

[0005] The purpose of this invention is to provide a non-contact Lorentz force flow meter and method suitable for high-temperature liquid metals. This invention is resistant to high temperatures and unaffected by liquid metal corrosion, and can be used for flow measurement of high-temperature (up to 1000℃) liquid metals. The flow meter's measuring component does not contact the high-temperature liquid metal, does not require connection to the pipeline under test, and can be used directly near the pipeline for measurement, with flexible measurement locations.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a non-contact Lorentz force flow meter suitable for high-temperature liquid metals, the flow meter comprising: an electromagnetic coil, an iron core, a force sensor, a transmitter, and a coil excitation power supply;

[0008] Electromagnetic coils are placed on both sides of the pipe to be tested and wound around a magnetically conductive iron core; the iron core is fixed to a force measuring bracket; the force measuring bracket is in contact with a force sensor, and the force sensor is connected to a transmitter; the electromagnetic coils are connected to a coil excitation power supply; the pipe to be tested is placed horizontally or vertically, and liquid metal flows in the pipe in a horizontal or vertical direction; the outer wall of the pipe to be tested is wrapped with a high-temperature resistant heat insulation layer.

[0009] A steady magnetic field is generated by an electromagnetic coil, with the magnetic field lines perpendicular to the flow direction of the liquid metal. The flow rate of the liquid metal in the pipe under test is measured by directly measuring the Lorentz force of the interaction between the liquid metal flowing in the pipe and the external magnet using a force sensor.

[0010] Furthermore, in order to enable the flow meter to measure the flow in pipes of various diameters, the iron core adopts a C-shaped adjustable length design, so that the magnetic lines of force pass through the pipe to be measured and form a closed magnetic flux loop through the iron core;

[0011] The core consists of two sections, which are fixed together by bolts. One section is a core with a boss, and the other section is a core with a groove. The total length of the core is adjusted by the length of the boss inserted into the groove of the core with the groove.

[0012] Furthermore, a compensating iron core of the same material is provided in the groove. The compensating iron core is used to ensure that there is no gap between the boss and the groove, which is conducive to the smooth flow of the magnetic circuit.

[0013] Furthermore, the end faces of both iron core sections are 2-5 mm away from the outer wall of the pipe to be tested.

[0014] Furthermore, the flow meter also includes a support base, which is fixed to the ground; the force sensor is mechanically fixed to the bracket of the support base.

[0015] Furthermore, in order to measure smaller flow rates and improve the accuracy of the flow meter, the flow meter also includes a horizontal slide rail with a linear air bearing, which helps to reduce the frictional resistance of the slide rail; the electromagnetic coil and the iron core are mechanically fixed to the horizontal slide rail, and the bottom of the horizontal slide rail is also mechanically fixed to the support base.

[0016] Furthermore, the force sensor has a resolution better than 1 millinewton; and the axis of the force sensor is parallel to the central axis of the pipe under test.

[0017] Furthermore, the coil excitation power supply is located away from the force sensor and transmitter.

[0018] Secondly, the present invention provides a measurement method for a non-contact Lorentz force flowmeter suitable for high-temperature liquid metals, as described above, the method comprising:

[0019] After the flow meter is installed, zero-point calibration of the flow meter should be performed;

[0020] The Lorentz force generated by the interaction between the moving liquid metal in the pipe under test and an external magnet is measured by a force sensor; the external magnet is generated by an electromagnetic coil, and the external magnet generates a steady magnetic field and the magnetic field lines cannot be parallel to the flow direction of the liquid metal.

[0021] The transmitter records and converts the Lorentz force into a flow signal for real-time display, thereby enabling the measurement of the flow rate of liquid metal in the pipeline under test.

[0022] Further, zero-point calibration of the flow meter is performed, including:

[0023] With the coil excitation power supply off and the liquid metal not flowing, connect the air bearing to the air source and perform zero-point calibration of the force sensor. At this time, the flow meter should display zero. Then turn on the coil excitation power supply and apply current to generate a magnetic field. Observe whether the zero point of the flow meter drifts.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] 1. This invention relates to a non-contact Lorentz force flow meter and method for measuring high-temperature liquid metals. This flow meter employs a non-contact measurement method, overcoming the challenge of measuring the flow of high-temperature, highly corrosive liquid metals. It can measure high-temperature liquid metals up to 800°C. The pipeline at the measurement point is intact, eliminating the risk of liquid metal leakage and providing inherent safety.

[0026] 2. This invention is applicable to a non-contact Lorentz force flow meter and method for high-temperature liquid metal. This flow meter does not need to be connected to the pipeline system to be measured, does not change the overall flow characteristics of the liquid metal in the pipeline to be measured, and the flow resistance generated at the measurement position is small, which hardly affects the flow rate of the entire pipeline.

[0027] 3. This invention is applicable to non-contact Lorentz force flow meters and methods for high-temperature liquid metals. It is easy to install and simple to measure. Simply place the flow meter close to the pipe to be measured. The measurement points are flexible and multiple points can be measured and cross-checked.

[0028] 4. This invention relates to a non-contact Lorentz force flow meter and method for high-temperature liquid metals. It has a large measuring range, enabling flow measurement of liquid metals with an average flow velocity of 0-20 m / s, and possesses high measurement accuracy. Due to the high measurement accuracy of the force sensor, and the use of air bearings in the horizontal slide rail system, it is possible to measure very small Lorentz forces in the horizontal direction. Therefore, this flow meter can still measure low-speed flowing liquid metals with high measurement accuracy.

[0029] 5. This invention relates to a non-contact Lorentz force flow meter and method for high-temperature liquid metals, with a wide range of applications: it is suitable for flow measurement of liquid metals in single-phase and gas-liquid two-phase flows, and can meet the safety monitoring needs in industrial metallurgy; in addition, the iron core adopts a length-adjustable design, and this flow meter is suitable for measurement needs of multiple pipe diameters, including flow measurement of liquid metals in small pipe diameters. Attached Figure Description

[0030] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0031] Figure 1 This is a schematic diagram of a non-contact flow meter for high-temperature liquid metal in horizontal flow according to the present invention;

[0032] Figure 2 This is a schematic diagram of the non-contact flow meter for high-temperature liquid metal in vertical flow according to the present invention;

[0033] Figure 3 This is a schematic diagram of the electromagnetic coil and iron core of the present invention;

[0034] Figure 4 This is a schematic diagram of the cross-section of the adjustable-length iron core of the present invention.

[0035] Figure reference numerals and corresponding component names:

[0036] 1-Pipe to be tested, 2-Insulation layer, 3-Electromagnetic coil, 4-Iron core, 41-Groove iron core, 42-Iron core with boss, 43-Fixing bolt, 44-Compensating iron core, 5-Force measuring bracket, 6-Force sensor, 7-Transmitter, 8-Coil excitation power supply, 9-Horizontal slide rail, 10-Support base. Detailed Implementation

[0037] In the following, the terms “comprising” or “may include” as used in various embodiments of the invention indicate the presence of an inventive function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in various embodiments of the invention, the terms “comprising,” “having,” and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0038] In various embodiments of the invention, the expression "or" or "at least one of A and / or B" includes any combination or all combinations of the words listed simultaneously. For example, the expression "A or B" or "at least one of A and / or B" may include A, may include B, or may include both A and B.

[0039] The expressions used in the various embodiments of the present invention (such as "first," "second," etc.) may modify various constituent elements in the various embodiments, but do not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing one element from other elements. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, a first element may be referred to as a second element without departing from the scope of the various embodiments of the present invention, and similarly, a second element may also be referred to as a first element.

[0040] It should be noted that if a description is made of "connecting" one component to another, then the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when a component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.

[0041] The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. The terms (such as those defined in a generally used dictionary) are to be interpreted as having the same meaning as in the context of the relevant technical field and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0043] Existing flow meters are unsuitable for measuring the flow of high-temperature liquid metals. Flow rate is a crucial operating parameter in the nuclear energy and metallurgical industries, closely related to the safe operation of equipment and facilities. Therefore, to meet the needs of high-temperature liquid metal flow measurement and monitoring in these industries, there is an urgent need to develop a high-temperature resistant, non-contact flow meter that is unaffected by liquid metal corrosion.

[0044] Based on the above, this invention designs a non-contact Lorentz force flow meter and method suitable for high-temperature liquid metals. To measure the flow rate of high-temperature liquid metals, this invention requires applying a high-temperature resistant insulation layer to the pipe under test; it also requires applying an external magnet that interacts with the liquid metal inside the pipe; the external magnet can be generated by an electromagnetic coil or a permanent magnet, and must be a stable magnetic field; the magnetic field lines of the external magnetic field must not be parallel to the flow direction of the liquid metal. This invention utilizes a force sensor to directly measure the Lorentz force of the interaction between the flowing liquid metal and the external magnet to measure the flow rate within the pipe under test.

[0045] The flow meter of this invention is resistant to high temperatures and is not corroded by liquid metals, and can be used for flow measurement of liquid metals at high temperatures (up to 1000°C). The measuring component of this flow meter does not come into contact with the high-temperature liquid metal, does not need to be connected to the pipeline to be measured, and can be measured directly near the pipeline to be measured, and the measurement point is flexible.

[0046] The working principle of this invention is described as follows:

[0047] Under an applied magnetic field, the flow of liquid metal in a pipe generates an induced current. This induced current interacts with the applied magnetic field to produce a Lorentz force that opposes the overall flow of the liquid metal. According to Newton's third law, a force of equal magnitude and opposite direction will act on the applied magnet; that is, the applied magnet will experience a Lorentz force in the same direction as the liquid metal flow. The magnitude of this force can be expressed as:

[0048] F=cσQB 2 L

[0049] in:

[0050] c: Dimensionless correction coefficient, which is related to the shape of the external magnet and the pipe;

[0051] σ: Electrical conductivity of liquid metal (S / m);

[0052] Q: Volumetric flow rate of liquid metal (m³) 3 / s);

[0053] B: Magnetic flux density (T) of the applied magnetic field at the center of the pipe under test;

[0054] L: The hydraulic diameter of the pipe (m).

[0055] Once the liquid metal, the applied magnetic field, and the pipe shape are determined, the above formula shows that the Lorentz force on the applied magnet increases linearly with the liquid metal flow rate. Therefore, by measuring the Lorentz force on the applied magnet, the flow rate in the pipe can be calculated, thus enabling non-contact measurement of the high-temperature liquid metal flow rate. Since the conductivity of liquid metal is as high as 10... 6 The Lorentz force generated by the interaction between liquid metal flowing in a pipe with an inner diameter of 100 mm and an external magnet under an applied magnetic field of 0.1 T (on the order of S / m) can reach the order of Newtons. Therefore, existing commercial force sensors can be used to accurately measure this force. Furthermore, the dimensionless correction coefficient c is independent of the physical properties of the liquid metal. Its value can be calibrated using a room-temperature liquid metal gallium-indium-tin circuit and applied to the calculation of flow rates of high-temperature liquid metals (such as lead-bismuth alloys, lithium-lead alloys, and high-temperature aluminum liquids).

[0056] The flow meter of the present invention includes a pipe to be measured 1, a high-temperature resistant heat insulation layer 2, an electromagnetic coil 3 or a permanent magnet, an iron core 4, a force measuring bracket 5, a force sensor 6, a transmitter 7, a coil excitation power supply 8, and a support base 10, etc.

[0057] The test pipe 1 is placed horizontally or vertically, and the liquid metal flows in the test pipe 1 in the horizontal or vertical direction; the outer wall of the test pipe 1 is wrapped with a high temperature resistant insulation layer 2, which is an inorganic insulation material that can withstand up to 1000℃. The thickness of the insulation layer is determined according to the temperature difference and the thermal conductivity of the insulation material, and finally meets the design requirement that the temperature of the outermost layer of the insulation layer is lower than 200℃.

[0058] Two electromagnetic coils 3 are located on both sides of the pipe 1 under test. The electromagnetic coils 3 are connected to the coil excitation power supply 8, ultimately forming a steady electromagnetic field. To increase the magnetic induction intensity, the electromagnetic coils 3 are wound around a magnetic core 4, which is made of DT4 ferromagnetic material. The core 4 adopts a C-shaped structure design, allowing magnetic lines of force to pass through the pipe 1 under test and form a closed magnetic flux loop through the core 4. The end faces of the core 4 on the upper and lower sides of the pipe 1 under test are circular. The N and S poles of the electromagnetic field are located on both sides of the pipe 1 under test, respectively. Magnetic lines of force pass through the pipe 1 from the N pole to the S pole, and the center line of the circular end face is in the same plane as the central axis of the pipe 1 along the flow direction.

[0059] To accommodate the measurement needs of pipes of different sizes, the C-shaped iron core features an adjustable length design, allowing the distance between the iron core 4 and the upper and lower end faces of the pipe 1 under test to be adjustable, thus meeting the measurement requirements of pipes with different diameters. The iron core 4 achieves its adjustable length function through a two-section design: one section has a boss, and the other has a groove. The total length of the iron core is adjusted by the length by which the boss is inserted into the groove, and the two sections are finally fixed together with bolts. To ensure a smoother magnetic circuit for the iron core 4, a compensating iron core of the same material is added to the groove, eliminating gaps between the boss and the groove and further facilitating a smooth magnetic circuit.

[0060] The flow measurement technology for high-temperature liquid metal flowing in a horizontal pipe is as follows:

[0061] The electromagnetic coil 3 and the iron core 4 are mechanically fixed to the horizontal slide rail 9 at the bottom. The horizontal slide rail 9 uses an air bearing, making the frictional resistance along the horizontal direction almost negligible. The horizontal slide rail 9 is made of non-magnetic stainless steel.

[0062] The force-measuring bracket 5 is mechanically fixed to the iron core 4 and is made of non-magnetic aluminum alloy. The center of the force-measuring bracket 5 is in contact with the force sensor 6 to measure the Lorentz force generated by the interaction between the electromagnetic coil 3 and the flowing liquid metal, and finally calculates the corresponding liquid metal flow rate in the pipe under test by using the magnitude of the force.

[0063] Force sensor 6 has a measurement accuracy of 0.1 millinewtons and a range from zero to hundreds of Newtons. Based on existing theory, the Lorentz force generated by the interaction between electromagnetic coil 3 and the liquid metal flowing in the pipe 1 can be estimated to be on the order of Newtons. Therefore, the force sensor with the above-mentioned range and accuracy can meet the relevant measurement requirements. Force sensor 6 is connected to transmitter 7, which converts the flow rate of the liquid metal into the actual flow rate of the liquid metal through a computing chip and displays it on the screen. It also outputs a measurement signal of 0 to 5V or 4 to 20mA for data acquisition.

[0064] Force sensor 6 is mechanically fixed to the bracket of support base 10, which is made of non-magnetic aluminum alloy. Additionally, the bottom of horizontal slide rail 9 is also mechanically fixed to support base 10, which is fixed to the ground.

[0065] For high-temperature liquid metal flowing downwards in a vertical pipe, the Lorentz force on the external magnet is in the same direction as the gravitational force. Compared with the horizontal flow condition, there is no need to overcome frictional resistance, and the technical solution is relatively simple, as described in detail below:

[0066] The iron core 4 of the magnet system is placed directly on the force sensor 6. To ensure the balance of the iron core 4, a force sensor 6 is placed on each side of the iron core 4 to measure the Lorentz force of the interaction between the flowing liquid metal and the external magnet.

[0067] Similar to the horizontal flow condition, force sensor 6 is connected to transmitter 7, which converts the flow rate of the liquid metal into a real flow rate via a computing chip and displays it on the screen. It also outputs a measurement signal of 0 to 5V or 4 to 20mA for data acquisition. Force sensor 6 is mechanically fixed to support base 10.

[0068] Example

[0069] like Figure 1 As shown, the present invention is applicable to a non-contact Lorentz force flow meter for high-temperature liquid metals. The flow meter includes: an electromagnetic coil 3, an iron core 4, a force sensor 6, a transmitter 7, and a coil excitation power supply 8.

[0070] Electromagnetic coils 3 are located on both sides of the pipe 1 to be tested and wound around a magnetically conductive iron core 4; the iron core 4 is fixed on a force measuring bracket 5; the force measuring bracket 5 is in contact with a force sensor 6, and the force sensor 6 is connected to a transmitter 7; the electromagnetic coils 3 are connected to a coil excitation power supply 8; wherein, the pipe 1 to be tested is placed horizontally or vertically, and liquid metal flows in the pipe 1 to be tested in a horizontal or vertical direction; the outer wall of the pipe 1 to be tested is wrapped with a high-temperature resistant heat insulation layer 2;

[0071] A steady magnetic field is generated by an electromagnetic coil 3, with the magnetic field lines perpendicular to the flow direction of the liquid metal. The flow rate of the liquid metal in the test pipe 1 is measured by directly measuring the Lorentz force of the interaction between the liquid metal flowing in the test pipe 1 and the external magnet using a force sensor.

[0072] As a further implementation, in order to enable the flow meter to measure the flow in pipes of various diameters, the iron core 4 adopts a C-shaped adjustable length design, so that the magnetic lines of force pass through the pipe 1 to be measured and form a closed magnetic flux loop through the iron core 4.

[0073] The iron core 4 includes two sections of iron core, which are fixed together by fixing bolts; one section is an iron core 42 with a boss, and the other section is an iron core 41 with a groove. The total length of the iron core 4 is adjusted by the length of the boss of the iron core 42 inserted into the groove of the iron core 41.

[0074] As a further implementation, a compensating iron core 44 of the same material is provided in the groove. The compensating iron core 44 is used to ensure that there is no gap between the boss and the groove, which is conducive to the smooth flow of the magnetic circuit.

[0075] As a further implementation, the end faces of both iron cores are 2-5 mm away from the outer diameter of the pipe wall of the pipe to be tested 1.

[0076] As a further implementation, the flow meter also includes a support base 10, which is fixed to the ground; the force sensor 6 is mechanically fixed to the bracket of the support base 10.

[0077] As a further implementation, in order to measure smaller flow rates and improve the accuracy of the flow meter, the flow meter also includes a horizontal slide rail 9 with a linear air bearing, which helps to reduce the frictional resistance of the slide rail; the electromagnetic coil 3 and the iron core 4 are mechanically fixed to the horizontal slide rail 9, and the bottom of the horizontal slide rail 9 is also mechanically fixed to the support base 10.

[0078] As a further implementation, the force sensor 6 has a resolution better than 1 millinewton; and the axis of the force sensor 6 is parallel to the central axis of the pipe 1 under test.

[0079] As a further implementation, the coil excitation power supply 8 is located away from the force sensor 6 and the transmitter 7.

[0080] The specific implementation is as follows:

[0081] Example 1: For horizontally flowing liquid metal, the detailed implementation scheme is as follows:

[0082] like Figure 1 As shown, the flow meter's support base 10 is placed below the pipe 1 to be measured. The horizontal slide rail 9 with a linear air bearing is fixed on the support base 10, and its upper surface is kept horizontal by adjustment. The magnet with iron core 4 is inserted into the pipe 1 to be measured. The end faces of the upper and lower iron cores are 2-5mm away from the outer wall of the pipe 1 to be measured, and the center line of the end faces is in the same vertical plane as the flow axis of the pipe 1 to be measured.

[0083] Electromagnetic coil 3 is connected to coil excitation power supply 8, which is connected to a 220V AC power supply and converted to DC power input into electromagnetic coil 3. This ultimately creates a stable magnetic field with magnetic field lines from N to S around the pipe under test 1, with a magnetic induction intensity of 0.05-0.2T at the center point of the pipe 1. The current value output by coil excitation power supply 8 has a one-to-one correspondence with this magnetic induction intensity. This correspondence can be determined using a Hall probe, and the relevant parameters are built into the chip of coil excitation power supply 8. Finally, the output current value and the corresponding magnetic induction intensity can be displayed on the power supply screen. After the electromagnetic field system is operating stably, the magnetic induction intensity value on the display screen is read and manually input into transmitter 7 for flow conversion.

[0084] A force sensor 6 with a measuring range of 0-20N (measuring accuracy of 0.1 millinewtons) is fixed on the bracket of the support base 10. The axis of the force sensor 6 is parallel to the central axis of the pipe to be measured 1 and is in contact with the force measuring bracket 5, which is fixed to the iron core 4 of the magnet. To reduce the frictional resistance of the bottom slide rail, the weight of the upper magnet and the force measuring bracket 5 should be minimized. This can be achieved by reducing the thickness of the iron core 4 and using a lightweight aluminum alloy to make the force measuring bracket. Alternatively, by using a linear air bearing on the bottom horizontal slide rail 9, the frictional resistance of the slide rail can also be reduced to a negligible level to ensure the measurement accuracy of smaller flow rates.

[0085] Figure 1 Force sensor 6 is connected to transmitter 7. Transmitter 7 has functions of calculation, signal conversion, and display. It can convert the measured Lorentz force signal into a flow rate signal of liquid metal in the pipe 1 under test for display. Through signal conversion, it can output a 4-20mA current signal, which can be connected to an industrial control computer for continuous acquisition and monitoring of the flow signal. The correction coefficient c required for transmitter 7 to convert the flow signal can be determined through a room-temperature liquid metal gallium indium tin circuit and manually input into transmitter 7 to achieve flow conversion for different pipe diameters. In addition, transmitter 7 also has a flow accumulation function, which can output the total volume of pumped fluid over a certain period of time.

[0086] After the flow meter of this invention is installed, under conditions where the magnetic field power supply is off and the liquid metal is not flowing, connect the air bearing to the air source, and then perform zero-point calibration of the force sensor 6. At this time, the flow meter display should be zero. Then turn on the electromagnetic field power system and apply current to generate a magnetic field, and observe whether the zero point of the flow meter drifts. To avoid affecting the normal operation of the pipeline system under test, the above-mentioned zero-point calibration work can be completed outside the measurement point. In addition, to reduce the influence of the power system on the force sensor 6 measurement, the power system should be placed as far away as possible from the force sensor 6 and the transmitter 7. The technical solution of this invention uses a steady magnetic field and does not generate alternating current, so its electromagnetic interference can be ignored.

[0087] After the flow meter zero-point calibration and the electromagnetic field system are stabilized, the measurement of liquid metal flow rate can begin. The Lorentz force generated by the interaction between the moving liquid metal in the test pipe 1 and the external magnet is measured by the force sensor 6, recorded by the transmitter 7, and converted into a flow signal for real-time display.

[0088] like Figure 3As shown, in order to achieve flow measurement of liquid metal in pipes with different inner diameters, the C-shaped iron core is designed to be length-extendable. The iron core is divided into two sections: one section with a boss is called the bossed iron core 42, and the other section with a groove is called the grooved iron core 41. By adjusting the depth of the boss inserted into the groove, the distance between the C-shaped iron core and the two end faces of the pipe to be measured can be adjusted to meet the measurement requirements of different pipe diameters.

[0089] like Figure 4 As shown, in order to ensure the smooth magnetic circuit of the adjustable length iron core, a compensating iron core 44 is added so that there is no gap between the boss and the groove, and it is finally fixed by the fixing bolt 43 on the groove.

[0090] Example 2: For liquid metal flowing vertically from top to bottom, the detailed implementation plan is as follows:

[0091] like Figure 2 As shown, the technical solution for vertical flow is relatively simpler compared to horizontal flow conditions. Since the Lorentz force on the magnet is in the same direction as gravity, there is no need for linear air bearings and horizontal guide rails 9 to reduce frictional resistance. This simplifies the technical solution and reduces manufacturing costs, making this solution the preferred choice.

[0092] Since the gravity of the external magnet also needs to be measured by the force sensor, this embodiment requires a force sensor 6 with a relatively large range. The force sensor 6 includes a first force sensor 61 and a second force sensor 62. Through the weight reduction design of the external magnet, the mass of the external magnet is reduced to 1Kg-5Kg. Therefore, for a vertically flowing flow meter, the range of the force sensor 6 is 0-70N. To maintain high measurement accuracy of the flow meter, a force sensor with an accuracy of 0.1 millinewtons can be selected.

[0093] When the liquid metal is not flowing, the gravity of the external magnet is first measured by force sensor 6 and used as a reference value. When the liquid metal flows vertically from top to bottom, the force on the external magnet is measured and the previously measured reference value is subtracted. This is the Lorentz force generated by the interaction between the flowing liquid metal and the external magnet. The Lorentz force value is recorded by transmitter 7 and converted into a flow signal value for real-time display.

[0094] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A non-contact Lorentz force flow meter suitable for high-temperature liquid metals, characterized in that, The flow meter includes: an electromagnetic coil (3), an iron core (4), a force sensor (6), a transmitter (7), and a coil excitation power supply (8). The electromagnetic coil (3) is located on both sides of the pipe (1) to be tested and wound around the magnetic core (4); the core (4) is fixed on the force measuring bracket (5); the force measuring bracket (5) is in contact with the force sensor (6), and the force sensor (6) is connected to the transmitter (7); the electromagnetic coil (3) is connected to the coil excitation power supply (8); wherein, the pipe (1) to be tested is placed horizontally or vertically, and the liquid metal flows in the pipe (1) to be tested in the horizontal or vertical direction; the outer wall of the pipe (1) to be tested is wrapped with a high-temperature resistant heat insulation layer (2). A steady magnetic field is generated by an electromagnetic coil (3), and the magnetic field lines are perpendicular to the flow direction of the liquid metal. The flow rate of the liquid metal in the pipe (1) is measured by directly measuring the Lorentz force of the interaction between the liquid metal flowing in the pipe (1) and the external magnet using a force sensor. The iron core (4) adopts a C-shaped adjustable length design, so that the magnetic lines of force pass through the pipe (1) to be tested and form a magnetic flux closed loop through the iron core (4); The iron core (4) includes two sections of iron core, which are fixed by fixing bolts; one section is an iron core (42) with a boss and the other section is an iron core (41) with a groove. The total length of the iron core (4) is adjusted by the length of the boss inserted into the groove of the iron core (41).

2. The non-contact Lorentz force flow meter suitable for high-temperature liquid metals according to claim 1, characterized in that, A compensating iron core (44) of the same material is provided in the groove. The compensating iron core (44) is used to ensure that there is no gap between the boss and the groove, which is conducive to the smooth flow of the magnetic circuit.

3. The non-contact Lorentz force flow meter suitable for high-temperature liquid metals according to claim 1, characterized in that, The end faces of the two iron core sections are 2-5 mm away from the outer wall of the pipe to be tested (1).

4. The non-contact Lorentz force flow meter suitable for high-temperature liquid metals according to claim 1, characterized in that, The flow meter also includes a support base (10) which is fixed to the ground; the force sensor (6) is fixed to the bracket of the support base (10).

5. The non-contact Lorentz force flow meter suitable for high-temperature liquid metals according to claim 4, characterized in that, The flow meter also includes a horizontal slide rail (9) with a linear air bearing, the electromagnetic coil (3) and the iron core (4) are fixed on the horizontal slide rail (9), and the bottom of the horizontal slide rail (9) is fixed on the support base (10).

6. The non-contact Lorentz force flow meter suitable for high-temperature liquid metals according to claim 1, characterized in that, The force sensor (6) has a resolution better than 1 millinewton; and the axis of the force sensor (6) is parallel to the central axis of the pipe (1) to be measured.

7. The non-contact Lorentz force flow meter suitable for high-temperature liquid metals according to claim 1, characterized in that, The coil excitation power supply (8) is located away from the force sensor (6) and the transmitter (7).

8. The measurement method for a non-contact Lorentz force flowmeter suitable for high-temperature liquid metals as described in any one of claims 1 to 7, characterized in that, The measurement method includes: After the flow meter is installed, perform zero-point calibration of the flow meter. The Lorentz force generated by the interaction between the moving liquid metal and the external magnet in the pipe (1) under test is measured by the force sensor (6); the external magnet is generated by the electromagnetic coil (3), and the external magnet generates a steady magnetic field and the magnetic field lines are not parallel to the flow direction of the liquid metal. The Lorentz force is recorded by the transmitter (7) and converted into a flow signal for real-time display, thereby realizing the measurement of the flow rate of liquid metal in the pipeline (1) to be measured.

9. The measurement method according to claim 8, characterized in that, Performing zero-point calibration of the flow meter includes: Under the condition that the coil excitation power supply (8) is not turned on and the liquid metal is not flowing, the air bearing is connected to the air source to perform zero-point calibration of the force sensor (6). At this time, the flow meter should display zero. Then turn on the coil excitation power supply (8) and apply current to generate a magnetic field. Observe whether the zero point of the flow meter drifts.

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