Explosion-proof magnetostrictive displacement sensor

Abstract

The application discloses an explosion-proof magnetostrictive displacement sensor and relates to the field of displacement sensors, which solves the problems of poor sealing, weak anti-interference ability and poor explosion-proof performance of the prior art magnetostrictive displacement sensor. The explosion-proof magnetostrictive displacement sensor comprises a first protective cover, a sensing circuit assembly, a measuring rod, a ring-shaped magnet and a second protective cover. The sensing circuit assembly comprises a filter plate, a pulse plate, a signal plate and a sensitive assembly. The measuring rod comprises a rod sleeve connected to the outer wall of the first protective cover, a position sensing assembly located in the rod sleeve and connected to the sensitive assembly and a shielding pipe sleeved on the outer wall of the position sensing assembly and located in the rod sleeve. An end of the second protective cover away from the first protective cover is formed with a penetrating hole for penetrating a cable, a rubber sleeve is arranged between the hole wall of the penetrating hole and the cable, the cable is electrically connected to the filter plate, and the pulse plate, the signal plate and the sensitive assembly are all electrically connected to the filter plate.

Description

Technical Field

[0001] This application relates to the field of displacement sensors, and specifically to an explosion-proof magnetostrictive displacement sensor. Background Technology

[0002] A magnetostrictive displacement sensor is a precision measuring device based on the magnetostrictive effect, capable of accurately detecting the displacement of an object by sensing changes in a magnetic field. Its core components typically include a waveguide wire and signal processing circuitry. It generates a mechanical stress wave by interacting with the magnetic field at the measured location through the instantaneous magnetic field produced by an excitation pulse, and accurately calculates the position of the measured object by detecting the time difference of the echo signal. This sensor features non-contact measurement, fast response speed, and long service life, and is widely used in industrial automation, liquid level monitoring, and mechanical motion control.

[0003] However, in existing technologies, when magnetostrictive displacement sensors are applied to environments with explosion hazards, such as coal mines, the presence of flammable and explosive gases like methane in these environments imposes stringent requirements on the sealing and explosion-proof performance of the sensor housing. Some displacement sensors have inadequately sealed housings, allowing external methane gases to enter the sensor and come into contact with electronic components, potentially causing an explosion during circuit operation due to electrical sparks or high temperatures. Furthermore, environments like coal mines may also contain dust, electromagnetic interference, and other factors that can affect the long-term reliable operation and measurement accuracy of the sensor. Utility Model Content

[0004] Therefore, this application provides an explosion-proof magnetostrictive displacement sensor to solve the problems of insufficient sealing, weak anti-interference ability, and poor explosion-proof performance of existing magnetostrictive displacement sensors.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] An explosion-proof magnetostrictive displacement sensor includes a first protective cover, a sensing circuit assembly connected to the inner wall of the first protective cover, a measuring rod connected to the outer wall of the first protective cover, an annular magnet sleeved on the outer wall of the measuring rod, and a second protective cover connected to the end of the first protective cover away from the measuring rod. The sensing circuit assembly includes a filter board, a pulse board, a signal board, and a sensitive component. The measuring rod includes a rod sleeve connected to the outer wall of the first protective cover, a position sensing component located inside the rod sleeve and connected to the sensitive component, and a shielding tube sleeved on the outer wall of the position sensing component and located inside the rod sleeve.

[0007] The second protective cover has a through hole for a cable at one end away from the first protective cover. A rubber sleeve is provided between the hole wall and the cable. The cable is electrically connected to the filter plate. The pulse plate, the signal plate and the sensitive component are all electrically connected to the filter plate. The adapter plate is connected to terminals that facilitate the connection of the cable.

[0008] Optionally, the second protective cover includes an adapter connected to the first protective cover, a tail wire connector connected to the end of the adapter away from the first protective cover, and a wire pass-through connector connected to the tail wire connector. The wire pass-through hole is formed in the wire pass-through connector. An adapter plate is connected to the inner wall of the adapter. The wire pass-through hole communicates with the inner cavity of the adapter. The cable is electrically connected to the adapter plate, and the adapter plate is electrically connected to the filter plate.

[0009] Optionally, the threading seat is connected to a clamping cap, the clamping cap including a cap body that facilitates tool operation and rotation, and a first connecting section integrally formed on the cap body and threaded to the wall of the threading hole. A limiting ring plate is integrally formed on the end of the threading hole near the tail wire seat, and the end of the first connecting section away from the cap body abuts against the rubber sleeve so that the rubber sleeve abuts against the limiting ring plate.

[0010] Optionally, the adapter is welded to the first protective cover, the tail wire holder includes a base body and a second connecting section integrally formed in the base body and threaded to the inner wall of the adapter, the wire threading holder is welded to the base body, and a sealing element is provided between the second connecting section and the inner wall of the adapter;

[0011] The inner cavity of the first protective cover is provided with a mounting base, and an isolation pad is connected between the mounting base and the inner cavity wall of the first protective cover. The sensing circuit assembly also includes a circuit board bracket. The filter board, the pulse board and the signal board are all connected to the circuit board bracket. The circuit board bracket is connected to the mounting base. The probe passes through the mounting base and the isolation pad and is connected to the sensitive component.

[0012] Optionally, a shield is connected between the filter plate and the mounting base, and the shield, the filter plate, and the mounting base form a receiving cavity for accommodating the sensing circuit assembly.

[0013] Optionally, the tail wire connector is connected to a grounding screw.

[0014] Optionally, the threading connector is connected to the end of the tail wire connector away from the adapter or to the side wall of the adapter.

[0015] Optionally, the first protective cover includes a cover body and a base connected to the cover body, a fastener is connected between the mounting base and the isolation pad, one end of the fastener is threaded to the base, and the rod sleeve is connected to the base.

[0016] Optionally, the annular magnet is connected to a non-magnetic pad.

[0017] Compared with the prior art, this application has at least the following beneficial effects:

[0018] The explosion-proof magnetostrictive displacement sensor of this application measures displacement based on the magnetostrictive effect. The cable passes through a through-hole into the second protective cover, is sealed by a rubber sleeve, and connects to a filter board, providing both power and data transmission. A pulse board sends an excitation signal to the position sensing component (waveguide wire) via a sensitive component. The excitation signal propagates along the position sensing component and generates a mechanical wave under the influence of the magnetic field of the ring magnet. This mechanical wave propagates along the position sensing component and is captured by the sensitive component. The sensitive component receives and processes the signal transmitted from the position sensing component, converts it into an electrical signal, and transmits it to a signal board. The signal board further optimizes the signal and finally outputs a position signal through an adapter board and cable.

[0019] A ring magnet is typically attached to the object being measured and moves with the object, thus changing the position of the position sensing component relative to it and generating a position signal. A shielding tube is fitted over the outer wall of the position sensing component, providing shielding protection and a physical seal. The design of the second protective cover provides a transition connection for the cable and achieves an airtight seal through a rubber sleeve in the through-hole, preventing flammable and explosive gases from seeping into the sensor along the cable path. Simultaneously, this design avoids the sealing problems that might occur if the cable directly passes through the first protective cover and connects to the sensing circuit assembly, thereby improving the sensor's sealing performance.

[0020] Through the above design, the sensor of this application can not only detect the displacement of the measured object with high precision, but also achieve good explosion-proof effect, effectively solving the safety hazards that may be caused by insufficient sealing in the prior art, and further broadening the application scenarios of magnetostrictive displacement sensors in dangerous environments. Attached Figure Description

[0021] To more intuitively illustrate the prior art and this application, several exemplary figures are provided below. It should be understood that the specific shapes and structures shown in the figures should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary figures, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0022] Figure 1 This is a schematic diagram of the overall structure of an explosion-proof magnetostrictive displacement sensor provided in one embodiment of this application;

[0023] Figure 2 for Figure 1 A cross-sectional view along the aa direction;

[0024] Figure 3 for Figure 2 Enlarged view of point A in the image;

[0025] Figure 4 for Figure 2 Enlarged view of point B in the image;

[0026] Figure 5 for Figure 2 Enlarged view of point C in the image;

[0027] Figure 6 A schematic diagram of the overall structure of an explosion-proof magnetostrictive displacement sensor provided in another embodiment of this application;

[0028] Figure 7 An exploded view of the sensing circuit assembly and measuring rod of an explosion-proof magnetostrictive displacement sensor provided in another embodiment of this application;

[0029] Figure 8 This is a partial exploded view of the structure of the second protective cover of an explosion-proof magnetostrictive displacement sensor provided in another embodiment of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. First protective cover; 11. Cover body; 12. Base; 2. Measuring rod; 21. Rod sleeve; 22. Position sensing component; 23. Shielding tube; 3. Ring magnet; 31. Non-magnetic pad; 4. Second protective cover; 41. Adapter; 42. Tail wire holder; 421. Seat body; 422. Second connecting section; 423. Grounding screw; 43. Wiring holder; 431. Limiting ring plate; 44. Compression cap; 441. Cap body; 442. First connecting section; 45. Rubber sleeve; 46. Adapter plate; 5. Sensing circuit assembly; 51. Circuit board bracket; 52. Pulse board; 53. Signal board; 54. Sensing component; 55. Mounting base; 56. Isolation pad; 57. Filter board; 58. Shielding cover; 59. Receiving cavity; 6. Cable. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0033] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "comprising," "including," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0034] refer to Figure 1-8 This application discloses an explosion-proof magnetostrictive displacement sensor, including a first protective cover 1, a sensing circuit assembly 5 connected to the inner cavity wall of the first protective cover 1, a measuring rod 2 connected to the outer wall of the first protective cover 1, an annular magnet 3 sleeved on the outer wall of the measuring rod 2, and a second protective cover 4 connected to the end of the first protective cover 1 away from the measuring rod 2. The sensing circuit assembly 5 includes a filter board 57, a pulse board 52, a signal board 53, and a sensing component 54. The measuring rod 2 includes a rod sleeve 21 connected to the outer wall of the first protective cover 1, a position sensing component 22 located inside the rod sleeve 21 and connected to the sensing component 54, and a shielding tube 23 sleeved on the outer wall of the position sensing component 22 and located inside the rod sleeve 21.

[0035] The second protective cover 4 has a through hole for the cable 6 at the end away from the first protective cover 1. A rubber sleeve 45 is provided between the hole wall and the cable 6. The cable 6 is electrically connected to the filter plate 57. The pulse plate 52, the signal plate 53 and the sensitive component 54 are all electrically connected to the filter plate 57.

[0036] The explosion-proof magnetostrictive displacement sensor of this application measures displacement based on the magnetostrictive effect. The cable 6 enters the second protective cover 4 through a through-hole, is sealed by a rubber sleeve 45, and connects to a filter board 57, providing both power and data transmission. The pulse board 52 sends an excitation signal to the position sensing component 22 (waveguide wire) via the sensing component 54. The excitation signal propagates along the position sensing component 22 and generates a mechanical wave under the influence of the magnetic field of the ring magnet 3. This mechanical wave propagates along the position sensing component 22 and is captured by the sensing component 54. The sensing component 54 receives and processes the signal transmitted from the position sensing component 22, converts it into an electrical signal, and transmits it to the signal board 53. The signal board 53 further optimizes the signal and finally outputs the position signal through the adapter board 46 and the cable 6.

[0037] The ring magnet 3 is typically attached to the object being measured and moves with the object, thereby changing the position of its relative position sensing component 22 and generating a position signal. A shielding tube 23 is fitted over the outer wall of the position sensing component 22, providing shielding protection and a physical seal. The design of the second protective cover 4 provides a transition connection for the cable 6 and achieves an airtight seal through a rubber sleeve 45 in the through-hole, preventing flammable and explosive gases from seeping into the sensor along the cable 6 path. Simultaneously, this design avoids the potential sealing problems that might result from the cable 6 directly passing through the first protective cover 1 and connecting to the sensing circuit component 5, thus improving the sensor's sealing performance.

[0038] Through the above design, the sensor of this application can not only detect the displacement of the measured object with high precision, but also achieve good explosion-proof effect, effectively solving the safety hazards that may be caused by insufficient sealing in the prior art, and further broadening the application scenarios of magnetostrictive displacement sensors in dangerous environments.

[0039] It should be noted that the position sensing component 22 is also called a waveguide wire; the sensing circuit component 5 and the measuring rod 2 are existing technologies; the sensing component 54 is connected to the pulse plate 52; the pulse plate 52 is connected to the signal plate 53; the signal plate 53 and the filter plate 57 are connected; and their structure and working principle will not be described in detail in this application.

[0040] In some embodiments, the filter board 57, pulse board 52, sensitive component 54 and signal board 53 can be structurally integrated into one unit or arranged separately; in addition, the filter board 57, pulse board 52, sensitive component 54 and signal board 53 are all connected to the circuit board bracket 51, and the circuit board bracket 51 connects and supports the filter board 57, pulse board 52, sensitive component 54 and signal board 53.

[0041] In some embodiments, the annular magnet 3 is connected to a non-magnetic pad 31.

[0042] The second protective cover 4 includes an adapter 41 connected to the first protective cover 1, a tail wire seat 42 connected to the end of the adapter 41 away from the first protective cover 1, and a wire pass-through seat 43 connected to the tail wire seat 42. A pass-through hole is formed in the wire pass-through seat 43. An adapter plate 46 is connected to the inner wall of the adapter 41. The pass-through hole communicates with the inner cavity of the adapter 41. The cable 6 is electrically connected to the adapter plate 46. The adapter plate 46 is electrically connected to the filter plate 57. The adapter plate 46 is connected to terminals that facilitate the connection of the cable 6, which can realize the quick assembly and disassembly of the cable 6.

[0043] In this application, the second protective cover 4 achieves a transition connection between the cable 6 and the filter board 57 via an adapter plate 46. During operation, the cable 6 passes through the through hole of the cable holder 43, and after being sealed by the rubber sleeve 45, it connects to the adapter plate 46. The adapter plate 46 supplies power to the sensing circuit assembly 5 via the cable 6 and transmits the position signal to the external control equipment. The adapter plate 46 further improves the sealing performance through physical separation.

[0044] The threading seat 43 is connected to a clamping cap 44. The clamping cap 44 includes a cap body 441 that is easy to rotate for tool operation and a first connecting section 442 that is integrally formed on the cap body 441 and threaded to the wall of the threading hole. A limiting ring plate 431 is integrally formed on the end of the threading hole wall near the tail wire seat 42. The end of the first connecting section 442 away from the cap body 441 is pressed against the rubber sleeve 45 so that the rubber sleeve 45 abuts against the limiting ring plate 431.

[0045] The cap 441 is located outside the cable guide 43 for easy operation with a wrench or other tools. During operation, by rotating the cap 441, the threads of the first connecting section 442 are gradually screwed into the wall of the through hole. As the end of the first connecting section 442 away from the cap 441 gradually presses against the rubber sleeve 45, the rubber sleeve 45 deforms under pressure and presses against the limiting ring plate 431. The deformation of the rubber sleeve 45 makes it fit tightly against the cable 6 and the wall of the through hole, forming an effective airtight seal and preventing flammable and explosive gases from seeping into the sensor through the path of the cable 6.

[0046] In some embodiments, a compression pad is provided between the rubber sleeve 45 and the limiting ring plate 431.

[0047] The adapter 41 is welded to the first protective cover 1. The tail wire holder 42 includes a seat body 421 and a second connecting section 422 integrally formed in the seat body 421 and threaded to the inner wall of the adapter 41. The wire thread holder 43 is welded to the seat body 421. A sealing element is provided between the second connecting section 422 and the inner wall of the adapter 41.

[0048] In some embodiments, the seal may be an O-ring;

[0049] The inner cavity of the first protective cover 1 is provided with a mounting base 55, and an isolation pad 56 is connected between the mounting base 55 and the inner cavity wall of the first protective cover 1. The circuit board bracket 51 is connected to the mounting base 55, and the probe 2 passes through the mounting base 55 and the isolation pad 56 and is connected to the sensitive component 54.

[0050] The adapter 41 is fixed to the first protective cover 1 by welding. The welding point forms a good airtight seal at the joint, preventing flammable and explosive gases from seeping into the sensor from the connection. The second connecting section 422 of the tail wire holder 42 is threaded to the inner wall of the adapter 41, and an O-ring provides further sealing at its contact point. Under pressure, the O-ring adheres tightly to the inner wall of the adapter 41, effectively blocking the entry of external gases; the welding between the wire guide 43 and the seat body 421 also uses the same sealing principle.

[0051] The mounting base 55 is connected to the inner cavity wall of the first protective cover 1 by an isolation pad 56, which ensures the insulation performance between the mounting base 55 and the base 12.

[0052] A shielding cover 58 is connected between the filter board 57 and the mounting base 55. The shielding cover 58, the filter board 57 and the mounting base 55 form a receiving cavity 59 for accommodating the sensing circuit assembly 5.

[0053] A receiving cavity 59 is formed between the filter board 57 and the mounting base 55 by a shield 58, which provides a second layer of protection for the sensing circuit assembly 5. The shield 58 isolates electromagnetic interference.

[0054] The explosion-proof magnetostrictive displacement sensor has an IP68 protection rating.

[0055] The tail wire connector 42 is connected to a grounding screw 423.

[0056] The tail wire connector 42 in this application effectively protects the internal circuitry of the sensor by connecting to the grounding screw 423. The grounding screw 423 is directly grounded to the external ground, safely releasing any static electricity or leakage current that may occur during sensor operation to the ground, thereby preventing static electricity accumulation or overcurrent from damaging the internal sensing circuit assembly 5.

[0057] In some embodiments, the threading connector 43 is connected to the end of the tail connector 42 away from the adapter 41 or to the side wall of the adapter 41.

[0058] The explosion-proof magnetostrictive displacement sensor of this application is designed with two different wiring methods according to the application requirements, namely the straight wiring type (see reference). Figure 1 ) and side-mounted lines (reference) Figure 6 These designs are adapted to different installation and wiring environments. In the straight-out cable design, the cable guide 43 is connected to the end of the tail cable holder 42 away from the adapter 41, and the cable 6 is led out from the tail of the sensor. In the side-out cable design, the cable guide 43 is connected to the side wall of the adapter 41, and the cable 6 is led out from the side of the sensor.

[0059] The first protective cover 1 includes a cover body 11 and a base 12 connected to the cover body 11. A fastener (which may be a screw) is connected between the mounting base 55 and the isolation pad 56. One end of the fastener is threaded to the base 12. The fastener fixes the mounting base 55 and the isolation pad 56 to the base 12. The rod sleeve 21 is connected to the base 12. The base 12 is welded to the cover body 11 to improve the sealing performance.

[0060] In some embodiments, the sensing circuit assembly 5 is modularly designed to facilitate fabrication and installation.

[0061] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

[0062] The present application has been described in a relatively specific and detailed manner above through general descriptions and specific embodiments. It should be understood that, based on the technical concept of the present application, several conventional adjustments or further innovations can be made to these specific embodiments; however, as long as they do not depart from the technical concept of the present application, the technical solutions obtained by these conventional adjustments or further innovations also fall within the protection scope of the claims of the present application.

Claims

1. An explosion-proof magnetostrictive displacement sensor, characterized in that, The device includes a first protective cover, a sensing circuit assembly connected to the inner wall of the first protective cover, a measuring rod connected to the outer wall of the first protective cover, an annular magnet sleeved on the outer wall of the measuring rod, and a second protective cover connected to the end of the first protective cover away from the measuring rod. The sensing circuit assembly includes a filter board, a pulse board, a signal board, and a sensitive component. The measuring rod includes a rod sleeve connected to the outer wall of the first protective cover, a position sensing component located inside the rod sleeve and connected to the sensitive component, and a shielding tube sleeved on the outer wall of the position sensing component and located inside the rod sleeve. The second protective cover has a through hole for a cable at one end away from the first protective cover. A rubber sleeve is provided between the hole wall and the cable. The cable is electrically connected to the filter plate. The pulse plate, the signal plate and the sensitive component are all electrically connected to the filter plate.

2. The explosion-proof magnetostrictive displacement sensor according to claim 1, characterized in that, The second protective cover includes an adapter connected to the first protective cover, a tail wire connector connected to the end of the adapter away from the first protective cover, and a wire pass-through connector connected to the tail wire connector. The wire pass-through hole is formed in the wire pass-through connector. An adapter plate is connected to the inner wall of the adapter. The wire pass-through hole communicates with the inner cavity of the adapter. The cable is electrically connected to the adapter plate. The adapter plate is electrically connected to the filter plate. The adapter plate is connected to terminals that facilitate the connection of the cable.

3. The explosion-proof magnetostrictive displacement sensor according to claim 2, characterized in that, The threading seat is connected to a clamping cap, which includes a cap body that facilitates tool operation and rotation, and a first connecting section integrally formed on the cap body and threaded to the wall of the threading hole. A limiting ring plate is integrally formed on the end of the threading hole near the tail wire seat. The end of the first connecting section away from the cap body is pressed against the rubber sleeve so that the rubber sleeve abuts against the limiting ring plate.

4. The explosion-proof magnetostrictive displacement sensor according to claim 2, characterized in that, The adapter is welded to the first protective cover. The tail wire holder includes a base body and a second connecting section integrally formed in the base body and threaded to the inner wall of the adapter. The wire threading holder is welded to the base body. A sealing element is provided between the second connecting section and the inner wall of the adapter. The inner cavity of the first protective cover is provided with a mounting base, and an isolation pad is connected between the mounting base and the inner cavity wall of the first protective cover. The sensing circuit assembly also includes a circuit board bracket. The filter board, the pulse board and the signal board are all connected to the circuit board bracket. The circuit board bracket is connected to the mounting base. The probe passes through the mounting base and the isolation pad and is connected to the sensitive component.

5. The explosion-proof magnetostrictive displacement sensor according to claim 4, characterized in that, A shield is connected between the filter board and the mounting base, and the shield, the filter board, and the mounting base form a cavity for accommodating the sensing circuit assembly.

6. The explosion-proof magnetostrictive displacement sensor according to claim 2, characterized in that, The tail wire connector is connected to a grounding screw.

7. The explosion-proof magnetostrictive displacement sensor according to claim 2, characterized in that, The threading connector is connected to the end of the tail wire connector away from the adapter or to the side wall of the adapter.

8. The explosion-proof magnetostrictive displacement sensor according to claim 4, characterized in that, The first protective cover includes a cover body and a base connected to the cover body. A fastener is connected between the mounting base and the isolation pad. One end of the fastener is threaded to the base, and the rod sleeve is connected to the base.

9. The explosion-proof magnetostrictive displacement sensor according to claim 1, characterized in that, The annular magnet is connected to a non-magnetic pad.

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