Hall high-precision overload-resistant magnetic liquid micro-pressure difference sensor

Abstract

The application relates to a Hall high-precision overload-resistant magnetic liquid micro-pressure difference sensor, which comprises a conductive structure with a U-shaped cavity, one detection shell is respectively and sealingly connected to the two ends of the conductive structure, an overload-resistant shell is sealingly connected to the top of each detection shell, a cylindrical permanent magnet is coaxially arranged in each detection shell, the outer diameter of the cylindrical permanent magnet is larger than the inner diameter of the overload-resistant shell and the cavity of the conductive structure; the conductive structure and the detection shell are filled with magnetic liquid, the lower end of the cylindrical permanent magnet is immersed in the magnetic liquid, the upper end of the cylindrical permanent magnet is out of the magnetic liquid, and a specific volume of the magnetic liquid is adsorbed on the upper and lower ends of the cylindrical permanent magnet; two Hall elements are symmetrically arranged on the outer wall of the detection shell. The sensor medium is used as an overload protection element, which can not only obviously absorb impact energy and reduce peak stress, but also automatically return to the original position after the overload is removed, so that the sensor can restore the normal working state and realize the self-recovery of the function, and the adaptability of the sensor is improved.

Description

Technical Field

[0001] This invention relates to the field of micro differential pressure sensor technology, and more specifically, to a Hall effect high-precision, overload-resistant magnetic liquid micro differential pressure sensor. Background Technology

[0002] Micro differential pressure sensors are widely used in the field of industrial technology. Compared with traditional micro differential pressure sensors, magnetic liquid micro differential pressure sensors fundamentally solve the bottlenecks of traditional sensors in terms of wear, lifespan, overload vulnerability and sensitivity by replacing the solid mechanical structure with a liquid magnetic liquid.

[0003] However, due to the limited range of the magnetic liquid differential pressure sensor, when the pressure difference it detects is too large, phenomena such as magnetic liquid overflow or damage to the permanent magnet may occur, which in turn cause the magnetic liquid differential pressure sensor to fail and contaminate the working conditions. As a result, the sensor cannot return to working state after the overload is removed, and it cannot meet the overload resistance function. Its reliability and durability under harsh working conditions are insufficient. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor, which possesses high overload resistance. By using the sensing medium as an overload protection element, it can not only significantly absorb impact energy and reduce peak stress, but also automatically return to its original position after the overload is released, enabling the sensor to resume normal operation. This achieves self-recovery of function and greatly improves the reliability and durability of the sensor under harsh working conditions.

[0005] The objective of this invention and the technical problem it solves are achieved by the following technical solution. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor proposed in this invention includes: a conductive structure with a U-shaped cavity, each end of which is sealed to a detection housing; each detection housing has an overload-resistant housing sealed to its top; the upper end of the overload-resistant housing can communicate with a gas valve; a cylindrical permanent magnet is coaxially mounted inside both detection housings, the outer diameter of which is larger than the inner diameter of the overload-resistant housing and the cavity of the conductive structure; both the conductive structure and the detection housings are filled with magnetic liquid, the lower end of the cylindrical permanent magnet is immersed in the magnetic liquid, the upper end extends out of the magnetic liquid, and a specific volume of magnetic liquid is adsorbed at both its upper and lower ends; two Hall elements are symmetrically arranged on the outer wall of one of the detection housings.

[0006] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0007] The aforementioned Hall-type high-precision, overload-resistant magnetic liquid differential pressure sensor has two Hall elements symmetrically distributed on the outer walls of both detection housings.

[0008] The aforementioned Hall-type high-precision, overload-resistant magnetic liquid differential pressure sensor has Hall elements distributed on the outer wall of the middle part of the detection housing.

[0009] The aforementioned Hall-type high-precision overload resistant magnetic liquid micro-differential pressure sensor has multiple sets of Hall elements distributed on the outer wall of each detection housing. Each set of Hall elements consists of two symmetrically distributed Hall elements, and different sets of Hall elements are evenly distributed along the circumference of the spacer housing.

[0010] The aforementioned Hall-effect high-precision, overload-resistant magnetic liquid differential pressure sensor has two cylindrical permanent magnets with the same or opposite magnetic pole directions.

[0011] The aforementioned Hall-effect high-precision, overload-resistant magnetic liquid differential pressure sensor uses a kerosene-based Fe3O4 magnetic liquid, but it can also be an oil-based, silicone-based, ester-based, or water-based Fe3O4 magnetic liquid.

[0012] The aforementioned Hall-effect high-precision overload resistant magnetic liquid micro differential pressure sensor has connecting flanges protruding outward from the outer periphery of both the upper and lower ends of the detection housing. Connecting flanges are also provided at both ends of the overload resistant housing and the conductive structure. The detection housing, the overload resistant housing, and the conductive structure are all connected and fixed through corresponding connecting flanges. The overload resistant housing can also be connected and fixed to the gas valve through the connecting flange at its upper end.

[0013] The aforementioned Hall-effect high-precision, overload-resistant magnetic liquid differential pressure sensor has flanges connected by bolts and nuts, with multiple through holes along the circumferential direction on the flanges for bolts to pass through.

[0014] In the aforementioned Hall-effect high-precision, overload-resistant magnetic liquid differential pressure sensor, the detection housing, the conductive structure, and the overload-resistant housing are all sealed by a sealing ring located at the connecting flange.

[0015] The aforementioned Hall-effect high-precision overload-resistant magnetic liquid differential pressure sensor is used such that, at the top end of both overload-resistant housings, both are connected to a gas valve, or at the top end of one overload-resistant housing is connected to a gas valve while the top end of the other overload-resistant housing is open.

[0016] Compared with existing technologies, this invention has significant advantages and beneficial effects. Through the above technical solution, this invention achieves considerable technological advancement and practicality, and has broad industrial application value, possessing at least the following advantages:

[0017] This invention constructs a built-in, highly efficient overload protection mechanism by designing the diameter of the conductive structure and the overload-resistant housing to be smaller than the outer diameter of the cylindrical permanent magnet. Within the rated differential pressure range, the permanent magnet can freely displace along the axial direction to achieve normal sensing function. When the system is subjected to positive or negative pressure impacts exceeding its range, the cylindrical permanent magnet generates excessive displacement. The magnetic fluid adsorbed on its surface is rapidly compressed at the smaller inner diameter inlet (at the lower port of the overload-resistant housing / the upper port of the conductive structure), instantly forming a flexible "liquid seal" with high surface tension. This liquid seal utilizes the incompressibility of the fluid to block the continued movement of the permanent magnet, limiting its displacement within a safe range, thereby converting the overload impact into the static pressure of the liquid for dissipation, effectively avoiding permanent damage caused by rigid collisions between the permanent magnet and the internal structure. This invention uses the sensing medium as an overload protection element without adding any extra components. It can not only significantly absorb impact energy and reduce peak stress, but also automatically return to its original position after the overload is released, so that the sensor can return to normal working state. This achieves self-recovery of function and greatly improves the reliability and durability of the sensor under harsh working conditions.

[0018] The structural dimensions of this invention can be changed according to actual needs. By changing the parameters of the cylindrical permanent magnet, the range and measurement sensitivity of the sensor can be adjusted. At the same time, it is not limited by size. Depending on the application scenario, the size and dimensions of the sensor can be redesigned and formulated based on the same principle. Compared with existing sensors with fixed range and sensitivity, this invention meets the different requirements for the range and sensitivity of micro differential pressure sensors in different occasions, thus improving the adaptability of the sensor. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor of the present invention.

[0020] [Explanation of Key Component Symbols]

[0021] 1. Conductive structure; 201. First detection housing; 202. Second detection housing; 301. First overload resistant housing; 302. Second overload resistant housing; 4. Magnetic fluid; 501. First Hall element; 502. Second Hall element; 503. Third Hall element; 504. Fourth Hall element; 601. First cylindrical permanent magnet; 602. Second cylindrical permanent magnet; 7. Bolt and nut; 8. Sealing ring. Detailed Implementation

[0022] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, describes the specific implementation, structure, features, and effects of the Hall-type high-precision anti-overload magnetic liquid micro-differential pressure sensor proposed according to the present invention.

[0023] Please see Figure 1 This is a schematic diagram of the structure of the Hall-effect high-precision overload-resistant magnetic liquid micro-differential pressure sensor of the present invention. The sensor includes a conductive structure 1, which is a U-shaped tube filled with magnetic liquid 4. A first detection housing 201 and a second detection housing 202 are respectively connected to the top of the two vertical tubes of the conductive structure 1. The upper end face of the first detection housing 201 is sealed to the lower end face of the first overload-resistant housing 301, and the upper end face of the second detection housing 202 is sealed to the lower end face of the second overload-resistant housing 302. The upper end of the cavity of the first detection housing 201 is connected to the cavity of the first overload-resistant housing 301, and the lower end is connected to the cavity of the U-shaped tube. The inner diameter of the cavity of the first detection housing 201 is larger than the inner diameters of the cavities of the first overload-resistant housing 301 and the conductive structure 1, such that a downward-facing stop surface is formed between the upper end of the first detection housing 201 and the lower end face of the first overload-resistant housing 301, and an upward-facing stop surface is formed between the lower end of the first detection housing 201 and the upper end face of the conductive structure 1. The upper end of the cavity of the second detection housing 202 is connected and conductively communicated with the cavity of the second overload-resistant housing 302, and the lower end is connected and conductively communicated with the cavity of the conductive structure 1. The inner diameter of the cavity of the second detection housing 202 is larger than the inner diameters of the second overload-resistant housing 302 and the conductive structure 1, such that a downward-facing stop surface is formed between the upper end of the second detection housing 202 and the lower end face of the second overload-resistant housing 302, and an upward-facing stop surface is formed between the lower end of the second detection housing 202 and the upper end face of the conductive structure 1. In this embodiment of the invention, the conductive structure 1 is a symmetrical structure with identical vertical tubes on both sides. The structures of the first detection housing 201 and the second detection housing 202 are identical, as are the structures of the first overload-resistant housing 301 and the second overload-resistant housing 302, but this is not a limitation.

[0024] The lower part of the cavities of the first detection housing 201 and the second detection housing 202 is filled with magnetic liquid 4. A first cylindrical permanent magnet 601 extending vertically is suspended in the magnetic liquid 4 within the cavity of the first detection housing 201, and a second cylindrical permanent magnet 602 extending vertically is suspended in the magnetic liquid 4 within the second detection housing 202. Both the first and second cylindrical permanent magnets 601 and 602 are magnetized axially, meaning the north and south poles are magnetized at both ends of the cylinder. This results in magnetic liquid 4 adsorbing onto both ends of the first and second cylindrical permanent magnets 601 and 602, with the magnetic liquid 4 accumulating and covering the ends of the permanent magnets, forming a dumbbell-shaped structure. In this embodiment, the center line of the first cylindrical permanent magnet 601 coincides with the center line of the cavity of the first detection housing 201, and the center line of the second cylindrical permanent magnet 602 coincides with the center line of the cavity of the second detection housing 202.

[0025] In one embodiment of the invention, the magnetic poles of the first cylindrical permanent magnet 601 and the second cylindrical permanent magnet 602 are aligned, but in other embodiments of the invention, the magnetic poles of the first cylindrical permanent magnet 601 and the second cylindrical permanent magnet 602 are aligned.

[0026] In this invention, the cylindrical permanent magnet is stably suspended in the magnetic liquid 4 under the action of the first-order buoyancy and Archimedes' buoyancy. Because the surface of the cylindrical permanent magnet is saturated with the magnetic liquid 4, the principle of magnetic liquid buoyancy effectively prevents the cylindrical permanent magnet from contacting or colliding with the inner wall of the detection housing. The magnetic liquid 4 not only provides second-order buoyancy, enabling the cylindrical permanent magnet to form a stable "liquid seal," but also possesses excellent lubricating properties, which can increase the range and sensitivity of the sensor, effectively improving its service life.

[0027] The first cylindrical permanent magnet 601 and the second cylindrical permanent magnet 602 have the same shape and size, and the inner diameter of the first overload protection housing 301, the second overload protection housing 302 and the cavity of the conductive structure 1 are all smaller than the outer diameter of the cylindrical permanent magnet.

[0028] The first detection housing 201 has a first Hall element 501 and a second Hall element 502 symmetrically distributed on the outer wall of its middle section, while the second detection housing 202 has a third Hall element 503 and a fourth Hall element 504 symmetrically distributed on its outer wall of its middle section. This invention uses two sets of differential Hall elements (first Hall element 501, second Hall element 502, third Hall element 503, and fourth Hall element 504) to monitor the magnetic field gradient in real time. This distribution method, on the one hand, converts the magnetic field gradient into an amplified differential signal through differential measurement, significantly improving sensitivity and common-mode interference immunity; on the other hand, the symmetrical distribution of the two sets of elements enables real-time self-calibration, effectively compensating for temperature drift and aging errors. Finally, by matching the signal with a "pressure-magnetic field" database, the pressure magnitude and direction are simultaneously calculated.

[0029] In this embodiment of the invention, the magnetic liquid 4 is a kerosene-based Fe3O4 magnetic liquid. However, in other embodiments, oil-based Fe3O4 magnetic liquid, silicone oil-based Fe3O4 magnetic liquid, ester-based Fe3O4 magnetic liquid, water-based Fe3O4 magnetic liquid, or other similar functional magnetic liquids may also be used. Magnetic liquids with different base carriers differ in parameters such as saturation magnetization and viscosity, thereby affecting the damping characteristics, response speed, and overall sensitivity of the sensor. Selection can be made according to the specific application scenario.

[0030] In this embodiment, the upper and lower outer peripheries of the first detection housing 201 and the second detection housing 202 both protrude outward to form connecting flanges. Connecting flanges are also provided on the outer periphery of the upper ends of the two vertical pipes of the conduction structure 1. The first detection housing 201 and the second detection housing 202 are connected and fixed to the upper ends of the vertical pipes on both sides of the conduction structure 1 through the connecting flanges. To ensure a seal between the first detection housing 201 and the second detection housing 202 and the conduction structure 1, a sealing ring 8 is also provided between the first detection housing 201 and the second detection housing 202 and the conduction structure 1. Preferably, the sealing ring 8 is located between the end-to-end connecting flanges, and the end-to-end connecting flanges are also provided with annular grooves adapted to the sealing ring 8. The connecting flanges of the detection housing and the conduction structure 1 are connected by bolts and nuts 7, wherein the connecting flanges are provided with through holes for the bolts to pass through.

[0031] The first overload-resistant housing 301 and the second overload-resistant housing 302 both have outwardly protruding connecting flanges at their upper and lower outer circumferences. The lower connecting flange is fitted and sealed to the corresponding upper connecting flange of the detection housing. The connection between the two is achieved by bolts and nuts 7. The connecting flange has multiple through holes distributed circumferentially for bolts to pass through. The seal between the two is achieved by a sealing ring 8 set in an annular groove on the mating end face of the connecting flange. The connecting flange at the upper end of the overload-resistant housing is used to connect to a gas valve. When the sensor of the present invention is in use, the upper ends of the first overload-resistant housing 301 and the second overload-resistant housing 302 can be connected to the gas valve simultaneously, or only one of them can be connected to the gas valve while the other remains open.

[0032] When the sensor of this invention is subjected to a micro-pressure, the cylindrical permanent magnet will undergo axial displacement within the detection housing, causing a change in the magnetic field strength at the locations of the two Hall elements symmetrically distributed on the outer wall of the detection housing. By detecting the magnetic field strength value sensed by the Hall elements and its rate of change, the magnitude and direction of the applied micro-pressure can be calculated. Furthermore, by adjusting the magnetic properties or geometric parameters of the cylindrical permanent magnet, the sensor's range and sensitivity can be flexibly adjusted. In this embodiment, the sensor acquires the magnetic field strength values ​​H1 and H2 of the first Hall element 501 and the second Hall element 502 in real time, and calculates their difference ΔH and the rate of change ΔH / Δt to achieve initial measurement. This differential measurement mechanism converts the weak absolute magnetic field signal into a significant relative difference signal, improving detection sensitivity while effectively suppressing common-mode interference such as ambient temperature fluctuations. Meanwhile, the symmetrically distributed third Hall element 503 and fourth Hall element 504 form a parallel redundant measurement group. By cross-comparing the output signals of the two groups of elements, the system can identify and compensate for synchronization errors caused by factors such as temperature drift and element aging in real time, thereby achieving dynamic self-calibration and ensuring the stability of long-term measurements. Finally, the system matches the processed difference signal with a pre-stored calibration database to synchronously calculate the magnitude and direction of the measured pressure.

[0033] Within the rated differential pressure range, the cylindrical permanent magnet can freely displace along the axial direction to achieve normal sensing function. When the system is subjected to positive or negative pressure impacts exceeding the range, the first cylindrical permanent magnet 601 and the second cylindrical permanent magnet 602 generate excessive displacement and move towards the overload-resistant housing or the conductive structure 1. Since the inner wall of the cavity of the overload-resistant housing and the conductive structure 1 is smaller than the outer diameter of the cylindrical permanent magnet and the detection housing, the magnetic liquid 4 adsorbed at both ends of the cylindrical permanent magnet will contact the stop surface at the upper or lower end of the detection housing before the cylindrical permanent magnet, and be axially stopped and limited by it. It is then rapidly compressed at the smaller inner diameter opening where the overload-resistant housing or the conductive structure 1 connects with the detection housing, instantly forming a flexible "liquid seal" with high surface tension. This liquid seal utilizes the incompressibility of the fluid to block the continued movement of the permanent magnet, limiting its displacement within a safe range, thereby converting the overload impact into the static pressure of the liquid for dissipation, effectively avoiding permanent damage caused by rigid collisions between the permanent magnet and the internal structure. This invention uses the sensing medium as an overload protection element without adding any extra components. It can not only significantly absorb impact energy and reduce peak stress, but also automatically return to its original position after the overload is released, so that the sensor can return to normal working state. This achieves self-recovery of function and greatly improves the reliability and durability of the sensor under harsh working conditions.

[0034] The sensor housing portion of this invention, specifically the U-shaped structure composed of the first overload-resistant housing 301, the second overload-resistant housing 302, the first detection housing 201, the second detection housing 202, and the conductive structure 1, is a symmetrical structure with identical left and right sides. In other embodiments of this invention, the sensor housing portion structure remains unchanged, but the third Hall element 503 and the fourth Hall element 504 on the outer wall of the second detection housing 202 can be omitted. In this case, measurement can be performed using a single set of Hall elements.

[0035] In another embodiment of the present invention, at least two sets of Hall elements may be distributed on the outer walls of the first detection housing 201 and the second detection housing 202. Each set of Hall elements consists of two Hall elements symmetrically distributed on the outer periphery of the detection housing. Different sets of Hall elements are evenly distributed in the middle of the detection housing along the circumference of the detection housing. Under the action of micro pressure, by analyzing the magnetic field difference between the symmetrically distributed sets of Hall elements, the direction of micro pressure can be determined more accurately. By comprehensively calculating the change in magnetic field strength, the magnitude of micro pressure can be obtained.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor, characterized in that, include: The conductive structure has a U-shaped cavity, with a detection housing sealed at each end. Each detection housing has an overload-resistant housing sealed at the top, and the upper end of the overload-resistant housing can be connected to a gas valve. Each detection housing contains a cylindrical permanent magnet coaxially mounted inside. The two cylindrical permanent magnets are identical, and their outer diameter is larger than the inner diameter of the overload-resistant housing and the conductive structure cavity. The lower part of the detection housing cavity and the conductive structure cavity are filled with magnetic fluid, and the cylindrical permanent magnets are suspended in the magnetic fluid. A specific volume of magnetic fluid is adsorbed at both the upper and lower ends of the magnets. Two Hall elements are symmetrically arranged on the outer wall of one of the detection housings.

2. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to claim 1, characterized in that, Hall elements are symmetrically distributed on the outer walls of both detection housings.

3. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to claim 2, characterized in that, The Hall elements are distributed on the outer wall of the middle part of the detection housing.

4. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to claim 2, characterized in that, Each detection housing has multiple sets of Hall elements distributed on its outer wall, and each set of Hall elements consists of two Hall elements symmetrically distributed.

5. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to claim 2, characterized in that, The magnetic poles of the two cylindrical permanent magnets are in the same or opposite directions.

6. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to any one of claims 1-5, characterized in that, The magnetic fluid is a kerosene-based, machine oil-based, silicone oil-based, ester-based, or water-based Fe3O4 magnetic fluid.

7. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to claim 6, characterized in that, The detection housing has outward protrusions at both the upper and lower outer peripheries to form connecting flanges. The overload-resistant housing and the conductive structure also have connecting flanges at both ends. The detection housing, the overload-resistant housing, and the conductive structure are all connected and fixed through corresponding connecting flanges. The overload-resistant housing can also be connected and fixed to the air valve through the connecting flange at its upper end.

8. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to claim 7, characterized in that, The connecting flanges are connected by bolts and nuts, and the connecting flanges have multiple through holes along the circumference for bolts to pass through.

9. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to claim 7, characterized in that, The detection housing, the conductive structure, and the overload-resistant housing are all sealed together by sealing rings installed at the connecting flanges.

10. The Hall-effect high-precision, overload-resistant magnetic liquid micro-differential pressure sensor according to claim 6, characterized in that, When the sensor is in use, the upper ends of both overload protection housings are connected to the air valve, or one of the overload protection housings is connected to the air valve while the upper end of the other overload protection housing is open.

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