Variable distance capacitive abrasive particle sensor and method of measurement

Abstract

The application discloses a variable-distance capacitive abrasive particle sensor, which comprises an adsorption electrode, a detection electrode and a measurement and control unit; a capacitive detection cavity is formed between the adsorption electrode and the detection electrode; an adsorption device is arranged in the adsorption electrode or outside the capacitive detection cavity, and the adsorption device is connected with a moving device; the measurement and control unit controls the adsorption magnetic pole of the adsorption device to move along the parallel direction of the surface of the adsorption electrode; one or more convex structures are arranged on the surface of the detection electrode in the vertical direction of the moving direction of the adsorption device, so as to form a variable-distance area of the capacitive detection cavity; when the adsorption magnetic pole moves, the abrasive particles in the detection cavity are driven to move along the surface of the adsorption electrode and pass through the variable-distance area. Different heights of the convex devices can produce different responses to metal particles of the same size, so that the size information of the metal abrasive particles can be obtained simultaneously by analyzing the output change of the sensor, and the actual needs of production can be better met.

Description

TECHNICAL FIELD

[0001] The present application relates to a sensor, in particular, it is especially related to a sensor and a measuring method capable of being used for on-line monitoring of ferromagnetic metal abrasive particle content in industrial fluids. BACKGROUND

[0002] The principle of capacitance detection has been widely used in the measurement of physical and chemical properties of industrial fluids such as lubricating oil, and it has also been reported that the capacitance measurement method is used to detect the content of ferromagnetic metal particles in lubricating oil. The main method is to use a magnet to adsorb the abrasive particles in the lubricating oil into the capacitance detection cavity. The increase of the abrasive particle content leads to the increase of the dielectric constant of the measured lubricating oil, and then the change of the capacitance is measured to reflect the change of the abrasive particle content in the lubricating oil.

[0003] The biggest problem in the practical application of the above technology is that the sensitivity of the sensor in measuring the abrasive particle content is too low, which is difficult to meet the basic measurement requirements of the user. This is because the content of the abrasive particles in the oil is generally very low, and the electrode spacing of the cylindrical capacitance sensor used in the prior art is fixed, which leads to the fact that the percentage of the abrasive particle content in the lubricating oil in the capacitance detection cavity is very small, and thus the dielectric constant of the measured oil is also very small. Therefore, it is difficult for the prior art to measure the small change of the abrasive particle content. Secondly, the capacitance sensor designed by the prior art cannot measure the size of the abrasive particles, and the size information of the abrasive particles is very important to the user, so the prior art is greatly limited in practical application.

[0004] The present application provides a variable-distance capacitance abrasive particle sensor and a measuring method, which is different from the working principle of the existing capacitance abrasive particle sensor and can effectively solve the above technical problems. SUMMARY

[0005] In view of the above defects of the prior art, the technical problem to be solved by the present application is to provide a variable-distance capacitance abrasive particle sensor and a measuring method to improve the sensitivity of abrasive particle measurement and obtain abrasive particle size information.

[0006] The present application provides a variable-distance capacitance abrasive particle sensor and a measuring method to improve the sensitivity of abrasive particle measurement and obtain abrasive particle size information.

[0007] To achieve the above-mentioned purpose, the present application provides a variable-distance capacitance abrasive particle sensor, which comprises an adsorption electrode, a detection electrode and a measurement and control unit; a capacitance detection cavity is formed between the adsorption electrode and the detection electrode;

[0008] An adsorption device is arranged inside the adsorption electrode or outside the capacitance detection cavity, and the adsorption device is connected with a motion device;

[0009] The measurement and control unit controls the adsorption magnetic pole of the adsorption device to move circularly along the parallel direction of the surface of the adsorption electrode;

[0010] The detection electrode surface is provided with one or more convex structures in the vertical direction of the movement direction of the adsorption magnetic pole, which constitutes the variable distance area of the capacitive detection cavity.

[0011] The adsorption magnetic pole drives the abrasive particles in the detection cavity to move along the adsorption electrode surface and pass through the variable distance area when moving.

[0012] Further, the two sides of the variable distance area are respectively provided with a particle adsorption area and a particle release area; or one side of the variable distance area is provided with a particle release area, and the other side of the particle adsorption area coincides with the variable distance area.

[0013] The adsorption magnetic pole performs periodic cyclic motion, and the initial position is located in the particle adsorption area, sequentially passes through the variable distance area and the particle release area, and the particle release area is provided with an insulating baffle.

[0014] Further, the movement mode of the adsorption magnetic pole includes reciprocating linear motion, rotation, or a combination of linear motion and rotation. The measurement and control unit measures the changes of capacitance and impedance between the adsorption electrode and the detection electrode.

[0015] Further, the adsorption electrode and the detection electrode constitute a coaxial cylindrical capacitive detection cavity, and the cylindrical capacitive detection cavity is a bypass type closed oil cavity structure or a straight insertion type open structure.

[0016] The bypass type closed oil cavity structure is provided with an oil inlet hole and an oil outlet hole, and the straight insertion type open structure is provided with an oil passage hole in the outer electrode wall.

[0017] Further, the adsorption electrode is an internal cylindrical electrode, and the cylindrical electrode is internally provided with the permanent magnet

[0018] Iron, the movement device is a stepping motor driving the permanent magnet to rotate, and the detection electrode is an external circular tube electrode.

[0019] The circular tube electrode and the cylindrical electrode are provided with a boss I, a boss II and an insulating baffle, the radial height of the boss I is less than the radial height of the boss II, and the edges of the insulating baffle respectively contact the surfaces of the internal cylindrical electrode and the circular tube electrode.

[0020] Further, the adsorption electrode is an external circular tube electrode, the circular tube electrode is externally provided with a permanent magnet, the movement device is a motor driving the permanent magnet to rotate along the outside of the circular tube electrode, the detection electrode is an internal cylindrical electrode, and the internal cylindrical electrode surface is provided with one or more axial convex structures and an insulating baffle, and the edges of the insulating baffle respectively contact the surfaces of the internal cylindrical electrode and the circular tube electrode.

[0021] Further, the adsorption electrode is an external circular tube electrode, a plurality of electromagnets are arranged outside the circular tube electrode, the detection electrode is an internal cylindrical electrode, an axial boss I, a boss II and an insulating baffle are sequentially arranged on the surface of the internal cylindrical electrode, the radial height of the boss I is less than the radial height of the boss II, and the measuring and controlling unit controls the electromagnets to be sequentially powered on and powered off in the direction from the boss I to the boss II, so that the adsorption magnetic field rotates along the circumference of the external circular tube electrode.

[0022] Further, the adsorption electrode is an internal cylindrical electrode, an adsorption device is arranged inside the cylindrical electrode, the movement device is a screw device driven by a motor to drive the adsorption device to move linearly, the detection electrode is an external circular tube electrode, a circular boss I, a circular boss II and an insulating baffle are sequentially arranged on the internal circular tube electrode in the axial direction, the radial height of the circular boss I is less than the radial height of the circular boss II, and the adsorption device releases the adsorbed metal particles by closing the current or rotating the magnetic pole direction after reaching the particle release area.

[0023] Further, the adsorption electrode is an external circular tube electrode, a plurality of electromagnets are arranged outside the circular tube electrode, the detection electrode is an internal cylindrical electrode, an axial boss I, a boss II and an insulating baffle are sequentially arranged on the surface of the internal cylindrical electrode, the radial height of the boss I is less than the radial height of the boss II, and the measuring and controlling unit controls the electromagnets to be sequentially powered on and powered off in the direction from the boss I to the boss II, so that the adsorption magnetic field rotates along the circumference of the external circular tube electrode.

[0024] Further, the adsorption electrode is an external circular tube electrode, a plurality of electromagnets are arranged outside the circular tube electrode, the detection electrode is an internal cylindrical electrode, an axial boss I, a boss II and an insulating baffle are sequentially arranged on the surface of the internal cylindrical electrode, the radial height of the boss I is less than the radial height of the boss II, and the measuring and controlling unit controls the electromagnets to be sequentially powered on and powered off in the direction from the boss I to the boss II, so that the adsorption magnetic field rotates along the circumference of the external circular tube electrode.

[0025] A measurement method of a variable-distance capacitive abrasive particle sensor, comprising the following steps:

[0026] a) install the sensor into an oil circuit; the adsorption device is always resident in the particle adsorption area, and the ferromagnetic particles in the oil are adsorbed to the surface of the adsorption electrode;

[0027] b) the measuring and controlling unit controls the adsorption magnetic pole of the adsorption device to start cyclic motion every certain time, sequentially passing through the variable-distance area and the particle release area;

[0028] c) the adsorption magnetic pole drives the adsorbed particles to move synchronously when moving, and when the adsorbed particles pass through the variable-distance area, the change amount of the capacitance and impedance output of the sensor increases, and for the same number and size of particles, the greater the radial height of the boss, the greater the change of the sensor output;

[0029] By comparing the changes of the capacitance and impedance output of the sensor caused by bosses of different heights, the number and size information of the adsorbed particles can be obtained;

[0030] d) After the adsorption device reaches the particle release area, the adsorbed particles are released by rotating the magnetic pole direction or blocking by the insulating baffle, and the adsorption magnetic pole of the adsorption device returns to the original position; by comparing the changes in the sensor output before and after the adsorption particles are released, the water content and other state information of the oil can be obtained.

[0031] For the sensor using electromagnet, when the adsorbed particles move to the last boss, the measurement and control unit controls the electromagnet to stop moving and gradually reduces the driving current of the electromagnet, and records the change data of the sensor output with the reduction of the current, so that the size distribution information of the adsorbed particles can be obtained.

[0032] The measurement method of the sensor of the present application is different from the working principle of the existing capacitive abrasive particle sensor.

[0033] The sensor of the present application adopts the mode of setting the protruding device inside the capacitor plate, which greatly reduces the distance between the capacitor plates in the variable distance area. When the distance value is reduced to be comparable to the size of the adsorbed metal particles, the adsorbed metal particles will significantly reduce the distance between the plates of the measured capacitor, and further cause the capacitance between the measured electrodes to

[0034] significantly increase, and the impedance value significantly decreases. This measurement principle is different from the method of measuring the change of the dielectric constant of the measured oil by the metal abrasive particles in the prior art. Therefore, when the adsorption device drives the adsorbed metal particles into the variable distance area of the present application, the change amount of the capacitance and impedance output of the sensor will significantly increase, thereby greatly improving the sensitivity of the sensor in measuring metal abrasive particles. Secondly, the present application adopts a plurality of protruding devices with different heights, which can produce different output responses to the same adsorbed abrasive particles, and thus the size information of the adsorbed abrasive particles can be obtained.

[0035] In addition, the present application adopts the mode of gradually reducing the current by electromagnet, thereby gradually reducing the strength of the adsorption magnetic field and the size of the adsorption force on the metal abrasive particles. Since the adsorbed metal abrasive particles are also subjected to the action force of the oil flow, the metal abrasive particles in the variable distance area will gradually detach from the variable distance area starting from small size abrasive particles, causing changes in the output of the sensor. By analyzing the relationship between the output change of the sensor and the current of the electromagnet, the size distribution of the adsorbed metal abrasive particles can be measured more accurately, and thus has greater value in practical application.

[0036] The beneficial effects of the present application are: the sensor of the present application sets the protruding device for reducing the distance between the capacitor plates, and adopts the mode of combined impedance measurement by capacitance measurement, to amplify the influence of metal particles on the output change of the sensor, thereby greatly improving the measurement sensitivity of the sensor. In addition, the mode of changing the driving current by electromagnet and the protruding devices with different heights produce different responses to metal particles of the same size, and by analyzing the output change of the sensor, the size information of the metal abrasive particles can be obtained at the same time, thereby better meeting the needs of production practice. BRIEF DESCRIPTION OF DRAWINGS

[0037] Fig. 1 is a schematic view of the axial structure of a variable-distance capacitive abrasive particle sensor;

[0038] Fig. 2 is a sectional view of the variable-distance capacitive abrasive particle sensor of Fig. 1 along the A-A direction;

[0039] Fig. 3 is a schematic view of the axial structure of an inner magnetic field rotating oil cavity sensor design;

[0040] Fig. 4 is a sectional view of the inner magnetic field rotating oil cavity sensor design of Fig. 3 along the B-B direction; Figure 3 Fig. 5 is a schematic view of the axial structure of an inner magnetic field rotating direct-insertion sensor design;

[0041] Fig. 6 is a sectional view of the inner magnetic field rotating direct-insertion sensor design of Fig. 5 along the C-C direction;

[0042] Figure 5 Fig. 7 is a schematic view of the axial structure of an electromagnet abrasive particle sensor;

[0043] Fig. 8 is a sectional view of the electromagnet abrasive particle sensor of Fig. 7 along the D-D direction;

[0044] Fig. 9 is a side view of an internal magnet axial movement sensor;

[0045] Fig. 10 is a sectional view of the internal magnet axial movement sensor of Fig. 9 along the E-E direction;

[0046] Fig. 11 is a side view of an external magnet axial movement sensor; Figure 9 Fig. 12 is a sectional view of the external magnet axial movement sensor of Fig. 11 along the F-F direction. DETAILED DESCRIPTION

[0047] The present application will be further described below in conjunction with the accompanying drawings and examples:

[0048] Example 1

[0049] As shown in Figs. 1 and 2, a variable-distance capacitive abrasive particle sensor adopts a bypass type closed oil cavity structure, with an external cylindrical electrode as the adsorption electrode 100 and an internal cylindrical electrode as the detection electrode 200.

[0050] As shown in Figs. 3 and 4, an inner magnetic field rotating oil cavity sensor design adopts a closed oil cavity structure, with an external cylindrical electrode as the adsorption electrode 100 and an internal cylindrical electrode as the detection electrode 200.

[0051] Figure 2 As shown in Figs. 5 and 6, an inner magnetic field rotating direct-insertion sensor design adopts a closed oil cavity structure, with an external cylindrical electrode as the adsorption electrode 100 and an internal cylindrical electrode as the detection electrode 200.

[0052] ​​In the embodiment, the adsorption electrode 100 and the detection electrode 200 are coaxially arranged, and the two ends are respectively provided with a first insulating sealing cover plate 113 and a second insulating sealing cover plate 114, and the oil inlet hole 111 and the oil outlet hole 112 are arranged on the circular tube electrode. The adsorption electrode 100 and the detection electrode 200 form a coaxial cylindrical capacitive detection cavity.

[0053] The adsorption device 300 is arranged outside the adsorption electrode 100, and the adsorption device 300 is a permanent magnet or an electromagnet. The adsorption magnetic field of the adsorption device 300 is arranged in a single direction, as indicated by the arrow of the adsorption magnetic pole 301. The adsorption device 300 is wrapped with a soft magnetic material outside the permanent magnet or the electromagnet.

[0054] The motion device 400 is a motor, and the adsorption device 300 is connected with the motion device 400 through a connecting component (any structure capable of achieving the connection function in the prior art can be adopted, and the specific limitation is not made here).

[0055] The motion device 400 is a motor, and the adsorption device 300 is connected with the motion device 400 through a connecting component (any structure capable of achieving the connection function in the prior art can be adopted, and the specific limitation is not made here).

[0056] The surface of the detection electrode 200 is provided with an axial protruding structure 201 in the vertical direction of the movement direction of the adsorption device 300, and the protruding structure 201 and the adsorption electrode 100 form a variable distance area 221 of the capacitive detection cavity. When the adsorption magnetic pole 301 moves, the abrasive particles in the detection cavity move along the surface of the adsorption electrode 100 and pass through the variable distance area 221.

[0057] In the application, as a further preferred, the length direction of the protruding structure 201 is perpendicular to the movement direction of the adsorption magnetic pole 301, the cross-sectional shape of the protruding structure 201 is a polygon, the polygon height d is less than the distance between the adsorption electrode 100 and the detection electrode 200, and the polygon width t is less than 20*d, so as to reduce the flow resistance of the fluid to be measured.

[0058] The initial position of the movement of the adsorption magnetic pole 301 is the particle adsorption area 222, the residence time of the adsorption magnetic pole 301 in the particle adsorption area 222 is greater than the movement time of the adsorption magnetic pole 301, and the particle release area 223 is provided with an insulating baffle 202, and the adsorbed particles can be released by the insulating baffle 202 or by removing the magnetic field of the adsorption magnetic pole 301. The adsorption magnetic pole 301 moves in a cycle, sequentially passing through the particle adsorption area 222, the variable distance area 221 and the particle release area 223, and then returning to the initial position of the movement.

[0059] Embodiment 2

[0060] Other than the basic same as Embodiment 1, further, as shown in FIG. 3 and FIG. 4, this embodiment is provided with a bypass type closed oil cavity structure. The adsorption electrode 100 is an internal cylindrical electrode 110, and the cylindrical electrode 110 is internally provided with the permanent magnet 310, specifically: the cylindrical electrode 110 is internally provided with the permanent magnet 310 radially distributed magnetic poles, and the permanent magnet 310 is wrapped with soft magnetic material outside, so that the adsorption magnetic field only exists in one direction, Figure 4 As shown by the arrow direction in FIG. 5.

[0061] Figure 4 The movement device 400 is a stepping motor 410, and the detection electrode 200 is an external cylindrical electrode 210; the measurement and control unit 500 controls the stepping motor 410 to drive the permanent magnet 310 to rotate periodically.

[0062] The cylindrical electrode 210 and the cylindrical electrode 110 are provided with a boss I 203, a boss II 204 and an insulating baffle 202, the area between the boss I 203 and the boss II 204 and the internal cylindrical electrode 110 is a variable distance area 221; the particle adsorption area 222 and the particle release area 223 are respectively arranged on both sides of the variable distance area 221; the particle adsorption area 222 is a capacitance detection area corresponding to the position where the magnetic pole of the adsorption magnet 310 is always present; the particle release area 223 is an area between the electrodes close to the insulating baffle 202 in the rotation direction of the stepping motor 410.

[0063] The radial height of the boss I 203 is less than the radial height of the boss II 204, and the edges of the insulating baffle 202 are respectively in contact with the surfaces of the internal cylindrical electrode 110 and the cylindrical electrode 210.

[0064] Embodiment 3

[0065] Embodiment 3

[0066] ​The embodiment is a straight-in sensor structure, which is basically the same as that of Embodiment 1, and further, as shown in FIG. 5 and Figure 6 The adsorption electrode 100 is an internal cylindrical electrode 110, the detection electrode 200 is a coaxially installed circular tube electrode 210, one end of the circular tube electrode 210 is an open structure, and the other end is sequentially provided with a mounting thread and a metal shell. The adsorption device 300 is a permanent magnet 310, which is coaxially installed in the internal cylindrical electrode 110 and connected with a stepping motor 410 through a rotating shaft. The control and measurement unit 500 controls the stepping motor 410 to drive the permanent magnet 310 to rotate in the circumferential direction of the internal cylindrical electrode 110. The circular tube electrode 210 is provided with an oil hole 224 for the inlet and outlet of oil. The internal cylindrical electrode 110 is sequentially provided with an axial boss I 203, a boss II 204 and an insulating baffle 202 on the surface. The radial height of the boss I 203 is less than that of the boss II 204. The permanent magnet 310 is wrapped with soft magnetic material to make the adsorption magnetic field unidirectionally distributed, and its resident position points to the boss I 203, causing the variable pitch area to coincide with the particle adsorption area. In practical application, the straight-in sensor structure of the adsorption magnetic field is usually installed downward in the oil pipe, so that the abrasive particles blocked by the insulating baffle flow away with the oil through the open end of the sensor.

[0067] Embodiment 4

[0068] The embodiment is a bypass type closed oil cavity structure, the adsorption electrode 100 is an external circular tube electrode 210, which is basically the same as that of Embodiment 1, and further, as shown in FIG. 7 and Figure 8 The circular tube electrode 210 is externally installed with a plurality of electromagnets 311 radially distributed along the circumference, the detection electrode 200 is an internal cylindrical electrode 110, the internal cylindrical electrode 110 is sequentially provided with an axial boss I 203, a boss II 204 and an insulating baffle 202 on the surface, the radial height of the boss I 203 is less than that of the boss II 204, and the control and measurement unit 500 controls the electromagnets 311 to be sequentially powered on and powered off along the direction from the boss I 203 to the boss II 204, so that the adsorption magnetic field rotates along the external circumference of the circular tube electrode 210. When the adsorption magnetic field drives the adsorbed particles to move to the boss II 204, the control and measurement unit 500 controls the driving current of the electromagnet 311 corresponding to the boss II 204 to gradually decrease in steps, records the change data of the sensor output with the decrease of the current, and can obtain the size distribution information of the adsorbed particles.

[0069] Embodiment 5

[0070] which is basically the same as that of Embodiment 1, and further, as shown inFigure 9 And Figure 10, this embodiment is a bypass type closed oil cavity structure. The adsorption electrode 100 is an internal cylindrical electrode 110, and the cylindrical electrode 110 is internally provided with a magnetic pole radially distributed adsorption device 300, which is a permanent magnet or electromagnet with bidirectional adsorption magnetic field, as shown by the arrow in Figure 10; the movement device 400 is a screw device 420 driven by a motor 410, and the detection electrode 200 is an external circular tube electrode 210, which is internally provided with a circular ring-shaped boss I 205, a circular ring-shaped boss II 206 and an insulating baffle 202 in sequence along the axial direction, the radial height of the circular ring-shaped boss I 205 is less than that of the circular ring-shaped boss II 206, and the insulating baffle 202 is a partial circular ring distributed on both sides of the detection cavity in the horizontal direction, and the connecting line of the two partial circular rings is perpendicular to the direction of the adsorption magnetic pole. The motor 410 rotates to drive the adsorption device 300 to move linearly along the screw 420, and when the adsorption device 300 reaches the particle release area 223, the adsorbed metal particles are released by closing the electromagnet current

[0071] The current mode releases the adsorbed metal particles, which flow away with the oil, or the rotating magnetic pole direction is reversed by 90 degrees, and the adsorption device 300 is driven back by the motor 410, and the adsorbed metal particles are blocked by the insulating baffle and flow away with the oil.

[0072] Embodiment 6

[0073] Other embodiments are basically the same as embodiment 1, and further, as shown in Figure 11 and Figure 12, this embodiment is a bypass type closed oil cavity structure. The adsorption electrode 100 is an external circular tube electrode 210, and the circular tube electrode 210 is externally provided with a magnetic pole radially distributed adsorption device 300, which is a permanent magnet or electromagnet with unidirectional adsorption magnetic field, the movement device 400 is a screw device 420 driven by a motor 410, and the detection electrode 200 is an internal cylindrical electrode 110, which is internally provided with a circular ring-shaped boss I 205 and a circular ring-shaped boss II 206 in sequence along the axial direction, the radial height of the circular ring-shaped boss I 205 is less than that of the circular ring-shaped boss II 206, and the motor 410 rotates to drive the adsorption device 300 to move linearly along the screw 420, and when the adsorption device 300 reaches the particle release area 223, the adsorbed metal particles are released by closing the electromagnet current or rotating the magnetic pole direction by 180 degrees, and the adsorbed metal particles are carried away by the oil flow, and then the motor 410 is reversed to drive the adsorption device 300 back to the particle adsorption area 222.

[0074] A measuring method of a variable pitch capacitive abrasive particle sensor, comprising the following steps:

[0075] a) install the sensor into the oil circuit; install the straight-in sensor head away from the motor part downward; the adsorption device 300 is always resident in the particle adsorption area 222, adsorbing the ferromagnetic particles in the oil liquid to the surface of the adsorption electrode 100;

[0076] b) the measurement and control unit 500 controls the adsorption magnetic pole 301 of the adsorption device 300 to start the cyclic motion every certain time, sequentially passing through the variable distance area 221 and the particle release area 223;

[0077] c) the adsorption magnetic pole 301 moves the adsorbed particles to move synchronously, when the adsorbed particles pass through the variable distance area 221, the change amount of the capacitance and impedance output of the sensor increases, for the same number and size of particles, the greater the radial height of the boss, the greater the change of the sensor output;

[0078] By comparing the changes of the sensor capacitance and impedance output caused by bosses of different heights, the number and size information of the adsorbed particles can be obtained;

[0079] d) after the adsorption device 300 reaches the particle release area 223, the adsorbed particles are released by the additional rotating magnetic pole direction of the oil liquid flow or the blocking of the insulating baffle 202, and the adsorption magnetic pole 301 of the adsorption device 300 returns to the original position; by comparing the changes of the sensor output before and after the adsorbed particles are released, the state information such as the water content of the oil liquid can be obtained.

[0080] For the sensor using electromagnet 311, when the adsorbed particles move to the last boss, the measurement and control unit controls the electromagnet 311 to stop moving and gradually reduce the driving current of the electromagnet 311, records the change data of the sensor output with the reduction of the current, and the size distribution information of the adsorbed particles can be obtained.

[0081] The above describes the preferred embodiments of the present application in detail. It should be understood that those skilled in the art can make many modifications and changes without creative labor according to the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the prior art by those skilled in the art according to the concept of the present application shall be within the protection scope determined by the claims.

Claims

1. A measurement method for a variable-gap capacitive abrasive sensor, characterized in that, Includes the following steps: a) Install the sensor into the oil circuit; the adsorption device (300) is stationed in the particle adsorption zone (222) to adsorb ferromagnetic particles in the oil onto the surface of the adsorption electrode (100); b) The measurement and control unit (500) controls the adsorption magnetic pole (301) of the adsorption device (300) to start cyclic movement at certain intervals, sequentially passing through the variable pitch zone (221) and the particle release zone (223). c) When the adsorption magnetic pole (301) moves, it drives the adsorption particles to move synchronously. When the adsorption particles pass through the variable pitch region (221), the changes in the capacitance and impedance output of the sensor increase. d) After the adsorption device (300) reaches the particle release zone (223), the adsorbed particles are released by the oil flow plus the direction of the rotating magnetic pole or by the blocking of the insulating baffle (202), and the adsorption magnetic pole (301) of the adsorption device (300) returns to its original position. The variable-pitch capacitive abrasive sensor includes an adsorption electrode (100), a detection electrode (200), and a measurement and control unit (500); a capacitive detection cavity is formed between the adsorption electrode (100) and the detection electrode (200); An adsorption device (300) is provided inside the adsorption electrode (100) or outside the capacitor detection cavity, and the adsorption device (300) is connected to a motion device (400). The measurement and control unit (500) controls the adsorption magnetic pole (301) of the adsorption device (300) to circulate in a direction parallel to the surface of the adsorption electrode (100); One or more protrusions (201) are provided on the surface of the detection electrode (200) in the direction perpendicular to the direction of movement of the adsorption magnetic pole (301), forming the variable pitch region (221) of the capacitance detection cavity. When the adsorption magnetic pole (301) moves, it drives the abrasive particles in the detection cavity to move along the surface of the adsorption electrode (100) and through the variable pitch region (221). The variable pitch region (221) is provided with a particle adsorption region (222) and a particle release region (223) on both sides; or a particle release region (223) is provided on one side of the variable pitch region (221), and the particle adsorption region (222) on the other side overlaps with the variable pitch region (221); The adsorption magnetic pole (301) undergoes periodic cyclical motion. Its initial position is located in the particle adsorption area (222), and it passes sequentially through the variable pitch area (221) and the particle release area (223). An insulating baffle (202) is provided at the particle release area (223).

2. A variable-pitch capacitive abrasive sensor, characterized in that: It includes an adsorption electrode (100), a detection electrode (200), and a measurement and control unit (500); a capacitance detection cavity is formed between the adsorption electrode (100) and the detection electrode (200); An adsorption device (300) is provided inside the adsorption electrode (100) or outside the capacitor detection cavity, and the adsorption device (300) is connected to a motion device (400). The measurement and control unit (500) controls the adsorption magnetic pole (301) of the adsorption device (300) to circulate in a direction parallel to the surface of the adsorption electrode (100); One or more protrusions (201) are provided on the surface of the detection electrode (200) in the direction perpendicular to the direction of movement of the adsorption magnetic pole (301), forming the variable pitch region (221) of the capacitance detection cavity. When the adsorption magnetic pole (301) moves, it drives the abrasive particles in the detection cavity to move along the surface of the adsorption electrode (100) and through the variable pitch region (221). The variable pitch region (221) is provided with a particle adsorption region (222) and a particle release region (223) on both sides; or a particle release region (223) is provided on one side of the variable pitch region (221), and the particle adsorption region (222) on the other side overlaps with the variable pitch region (221); The adsorption magnetic pole (301) undergoes periodic cyclical motion, initially located in the particle adsorption region (222), and sequentially passes through the variable-pitch region (221) and the particle release region (223). An insulating baffle (202) is provided at the location; the movement mode of the adsorption magnetic pole (301) includes reciprocating linear motion, rotation, or a combination of linear motion and rotation; the measurement and control unit (500) measures the capacitance and impedance changes between the adsorption electrode (100) and the detection electrode (200).

3. The variable-pitch capacitive abrasive sensor as described in claim 2, characterized in that: The adsorption electrode (100) and the detection electrode (200) form a coaxial cylindrical capacitor detection cavity, wherein the cylindrical capacitor detection cavity is a bypass-type closed oil cavity structure or a direct-insertion open structure; The bypass-type closed oil chamber structure is provided with an oil inlet (111) and an oil outlet (112), and the outer electrode wall of the straight-insertion open structure is provided with an oil passage hole (224).

4. The variable-pitch capacitive abrasive sensor as described in claim 3, characterized in that: The adsorption electrode (100) is an internal cylindrical electrode (110), and a permanent magnet (310) is provided inside the cylindrical electrode (110). The motion device (400) is a stepper motor (410) that drives the permanent magnet (310) to rotate. The detection electrode (200) is an external cylindrical electrode (210). A boss I (203), a boss II (204), and an insulating baffle (202) are provided between the circular tube electrode (210) and the cylindrical electrode (110). The radial height of the boss I (203) is less than the radial height of the boss II (204). The edge of the insulating baffle (202) is in contact with the surfaces of the inner cylindrical electrode (110) and the circular tube electrode (210), respectively.

5. The variable-pitch capacitive abrasive sensor as described in claim 3, characterized in that: The adsorption electrode (100) is an outer cylindrical electrode (210), and a permanent magnet (310) is provided on the outside of the cylindrical electrode (210). The motion device (400) is a motor (410) that drives the permanent magnet (310) to rotate along the outside of the cylindrical electrode (210). The detection electrode (200) is an inner cylindrical electrode (110), and one or more axial protrusions (201) and insulating baffles (202) are provided on the surface of the inner cylindrical electrode (110). The edges of the insulating baffles (202) are in contact with the surfaces of the inner cylindrical electrode (110) and the cylindrical electrode (210), respectively.

6. The variable-pitch capacitive abrasive sensor as described in claim 3, characterized in that: The adsorption electrode (100) is an outer cylindrical electrode (210), and several electromagnets (311) are arranged on the outside of the cylindrical electrode (210). The detection electrode (200) is an inner cylindrical electrode (110), and an axial boss I (203), a boss II (204) and an insulating baffle (202) are arranged sequentially on the surface of the inner cylindrical electrode (110). The radial height of the boss I (203) is less than the radial height of the boss II (204). The measurement and control unit (500) controls the electromagnets (311) to be energized and de-energized sequentially along the direction from the boss I (203) to the boss II (204), so that the adsorption magnetic field rotates along the outer circumference of the cylindrical electrode (210).

7. The variable-pitch capacitive abrasive sensor as described in claim 3, characterized in that: The adsorption electrode (100) is an internal cylindrical electrode (110), and an adsorption device (300) is installed inside the cylindrical electrode (110). The motion device (400) is a screw device (420) driven by a motor (410) to drive the adsorption device (300) to move linearly. The detection electrode (200) is an external cylindrical electrode (210), and an annular boss I (205), an annular boss II (206) and an insulating baffle (202) are arranged sequentially along the axial direction inside the annular boss I (205). The radial height of the annular boss I (205) is less than the radial height of the annular boss II (206). After the adsorption device reaches the particle release area (223), it releases the adsorbed metal particles by turning off the current or rotating the magnetic pole direction.

8. The variable-pitch capacitive abrasive sensor as described in claim 3, characterized in that: The adsorption electrode (100) is an external cylindrical electrode (210), and an adsorption device (300) is installed on the outside of the cylindrical electrode (210). The motion device (400) is a screw device (420) driven by a motor (410) to drive the adsorption device (300) to move linearly. The detection electrode (200) is an internal cylindrical electrode (110). Circular bosses I (205) and II (206) are arranged sequentially along the axial direction on the surface of the internal cylindrical electrode (110). The radial height of the circular boss I (205) is less than the radial height of the circular boss II (206). After the adsorption device (300) reaches the particle release area (223), it releases the adsorbed metal particles by turning off the current or rotating the magnetic pole direction.

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