A device and method for distinguishing and detecting mixed abrasive oil particles

Abstract

This invention provides a device and method for distinguishing and detecting overlapping abrasive particles in oil, comprising: a three-coil microfluidic chip, a signal conditioning unit, and a data acquisition card connected in sequence. The three-coil microfluidic chip, in conjunction with the signal conditioning unit, analyzes the characteristics of overlapping particles by considering phase, amplitude, and the number of peaks and troughs. The three-coil microfluidic chip includes a glass substrate and a chip body disposed on the glass substrate. The chip body includes an oil inlet, a PDMS substrate, a microchannel, an oil outlet, two excitation coils, and an induction coil. The excitation coil and the induction coil are respectively wound on the microchannel and embedded inside the PDMS substrate. One port of the microchannel serves as the oil inlet, and the other port serves as the oil outlet. The induction coil is disposed between the two excitation coils. The signal conditioning unit includes a half-wave rectifier circuit, a low-pass filter circuit, a lock-in amplifier, and a post-amplifier connected in sequence. This invention solves the problem that existing inductive oil detection technologies cannot distinguish and detect signals of overlapping particles.

Description

Technical Field

[0001] This invention relates to the field of oil detection and analysis technology, and more particularly to a device and method for distinguishing and detecting mixed abrasive oil particles. Background Technology

[0002] Oil fluid testing and analysis technology involves the quantitative and qualitative analysis of the physicochemical properties and contaminant particles in the oils (hydraulic oil, lubricating oil, etc.) within mechanical equipment. The presence of numerous large abrasive particles in the oil indicates abnormal wear in the mechanical system. If this is not detected and repaired promptly, a domino effect will occur: abrasive particles exacerbate wear, further wear increases, and a vicious cycle continues until the entire system collapses. Therefore, timely and effective testing of the oils in mechanical systems is a direct means of preventing accidents and reducing losses.

[0003] There are various methods for oil detection, with commonly used particle counting methods including acoustic detection, optical detection, capacitance detection, and inductive detection. Compared to other methods, inductive detection is less affected by the quality of the oil sample and environmental noise, and can simultaneously distinguish between ferromagnetic and non-ferromagnetic particles. Furthermore, by changing the specific excitation signal, it can also differentiate non-ferromagnetic metals, making it more widely used. However, its output signal shape is relatively simple, with fewer characteristic signals. It can only determine the particle size and material of the abrasive particles through the signal amplitude and phase, and cannot distinguish signals when multiple particles pass through in a superimposed manner. Summary of the Invention

[0004] To address the technical problem that existing inductive oil detection technologies cannot distinguish and detect superimposed particle signals, this invention provides a device and method for distinguishing and detecting mixed abrasive oil particles. This invention designs a three-coil sensor based on a microfluidic chip, which possesses more signal characteristics and can analyze the output characteristics when different materials pass through the three coils at different intervals.

[0005] The technical means employed in this invention are as follows:

[0006] A device for distinguishing and detecting overlapping abrasive particles in oil includes: a three-coil microfluidic chip, a signal conditioning unit connected to the three-coil microfluidic chip, and a data acquisition card connected to the signal conditioning unit. The three-coil microfluidic chip, in conjunction with the signal conditioning unit, analyzes the characteristics of overlapping particles through phase, amplitude, and the number of peaks and troughs.

[0007] The three-coil microfluidic chip includes a glass substrate and a chip body disposed on the glass substrate; the chip body includes an oil inlet, a PDMS substrate, a microchannel, an oil outlet, two excitation coils, and an induction coil; in the chip body: the two excitation coils and the induction coil are respectively wound on the microchannel and are all embedded inside the PDMS substrate, one port of the microchannel serves as the oil inlet, the other port serves as the oil outlet, and the induction coil is disposed between the two excitation coils;

[0008] The signal conditioning unit includes a half-wave rectifier circuit, a low-pass filter circuit, a lock-in amplifier, and a post-amplifier, which are connected in sequence.

[0009] Furthermore, the two excitation coils are wound in opposite directions, with each excitation coil having 300 turns and an inner diameter of 1300 μm.

[0010] Furthermore, the two excitation coils are connected in parallel to the waveform generator, and the two ends of the induction coil are connected to the signal conditioning unit.

[0011] Furthermore, the induction coil and the two excitation coils are all made of copper wire with a diameter of 70μm.

[0012] The present invention also provides a method for distinguishing and detecting mixed abrasive oils based on the above-mentioned mixed abrasive oil distinguishing and detecting device, comprising:

[0013] Individual 500μm and 700μm iron particles and 500μm and 700μm copper particles are attached to ultrafine plastic fibers. The particles are reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal of one of the back-and-forth movements is captured.

[0014] When a single iron particle passes through the three-coil microfluidic chip, the output signal shows two peaks and two troughs, and the peak and trough signals are different in magnitude, and the signal is symmetrical about the center point;

[0015] When a single copper particle passes through the three-coil microfluidic chip, the output signal shows two peaks and troughs, but the trough signal is obvious and the signal is not symmetrical about the center point.

[0016] Furthermore, the method for distinguishing and detecting mixed abrasive oils also includes:

[0017] A 500μm iron particle and a 700μm copper particle are attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. The particles are reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal from one of the back-and-forth movements is captured.

[0018] When the particle spacing is 0mm, the copper particles enter the excitation coil first, so the initial phase is the same as that of the copper particles. When the iron particles enter the excitation coil, only part of the copper particles remain in the excitation coil, so it only weakens the peak value of the iron particles. The output signal is similar to that of the copper particles, but it will produce two peaks and three troughs with different amplitudes.

[0019] When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through.

[0020] When the particle spacing is 2mm, the signal will show three peaks and troughs, but the amplitudes are different.

[0021] When the particle spacing is 3mm, the signal will show four peaks and troughs.

[0022] Furthermore, the method for distinguishing and detecting mixed abrasive oils also includes:

[0023] A 500μm copper particle and a 700μm iron particle are attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. The particles are reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal from one of the reciprocating motions is captured.

[0024] When the two particles are 0mm apart, compared to the signal of a single 700μm iron particle, there is only a change in amplitude. At this time, the signal has two peaks and troughs.

[0025] When the particle spacing is 1 mm, the signal will show three peaks and two troughs;

[0026] When the particle spacing is 2mm, the signal will show three peaks and three troughs with different amplitudes.

[0027] When the particle spacing is 3mm, the signal will show three peaks and four troughs.

[0028] Furthermore, the method for distinguishing and detecting mixed abrasive oils also includes:

[0029] Two 700μm copper particles were attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. The particles were then reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal from one of the reciprocating movements was captured.

[0030] When the particle spacing is 0mm, since the sum of the diameters of two 700μm copper particles is 1.4mm and the width of the excitation coil is 1mm, the two copper particles cannot appear in the excitation coil at the same time, so the impact on the signal amplitude is small.

[0031] When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through.

[0032] When the particle spacing is 2mm, the signal will have three peaks and troughs, but their amplitude and signal change trend are different.

[0033] When the particle spacing is 3mm, the signal will show four peaks and troughs.

[0034] Furthermore, the method for distinguishing and detecting mixed abrasive oils also includes:

[0035] Two 500μm iron particles were attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. The particles were then reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal from one of the reciprocating movements was captured.

[0036] When the particle spacing is 0mm, since two 500μm iron particles can appear in the excitation coil at the same time, it has a significant impact on the signal amplitude. The maximum peak value is 400mV and the maximum trough value is 390mV. Two peaks and two troughs will appear. The waveform at this time is similar to the signal generated by a single 700μm iron particle, but the values ​​of the two peaks and troughs are not the same. Therefore, they can be distinguished by the values ​​of the two peaks and troughs.

[0037] When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through.

[0038] When the particle spacing is 2mm, the signal will show three peaks and troughs, but their amplitudes are different.

[0039] When the particle spacing is 3mm, the signal will show four peaks and troughs.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] The mixed abrasive oil differentiation detection device and its detection method provided by the present invention can realize the output characteristic analysis when abrasive particles of different materials and mixed at different intervals pass through three coils.

[0042] Based on the above reasons, this invention can be widely applied in fields such as oil detection. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a structural diagram of the three-coil microfluidic chip of the present invention.

[0045] Figure 2 This is a flowchart of the detection process of the detection device of the present invention.

[0046] Figure 3 The induced voltage of a single particle of different size and material provided in the embodiments of the present invention.

[0047] Figure 4 The induced voltages of 500µm iron particles and 700µm copper particles at different spacings provided in the embodiments of the present invention.

[0048] Figure 5 The induced voltages of 500μm copper particles and 700μm iron particles at different spacings provided in the embodiments of the present invention.

[0049] Figure 6 The induced voltage of two 700μm copper particles at different spacings provided in this embodiment of the invention.

[0050] Figure 7 The induced voltage of two 500μm iron particles at different spacings provided in this embodiment of the invention.

[0051] In the diagram: 1. Oil inlet; 2. PDMS substrate; 3. Microfluidic channel; 4. Glass substrate; 5. Oil outlet; 6. First excitation coil; 7. Induction coil; 8. Second excitation coil; 9. Circuit diagram of the three-coil microfluidic chip; 10. Signal conditioning unit; 11. Data acquisition card; 12. Half-wave rectifier circuit; 13. Low-pass filter circuit; 14. Lock-in amplifier; 15. Post-amplifier. Detailed Implementation

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0055] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0056] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0057] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0058] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0059] This invention provides a device for distinguishing and detecting overlapping abrasive particles in oil, comprising: a three-coil microfluidic chip, a signal conditioning unit 10 connected to the three-coil microfluidic chip, and a data acquisition card 11 connected to the signal conditioning unit 10. The three-coil microfluidic chip, in conjunction with the signal conditioning unit 10, analyzes the characteristics of overlapping particles through phase, amplitude, and the number of peaks and troughs.

[0060] like Figure 1 As shown, the three-coil microfluidic chip includes a glass substrate 4 and a chip body disposed on the glass substrate 4. The chip body includes an oil inlet 1, a PDMS substrate 2, a microchannel 3, an oil outlet 5, two excitation coils (a first excitation coil 6 and a second excitation coil 8), and an induction coil 7. In the chip body, the first excitation coil 6, the second excitation coil 8, and the induction coil 7 are respectively wound on the microchannel 3 and are all embedded inside the PDMS substrate 2. One port of the microchannel 3 serves as the oil inlet 1, and the other port serves as the oil outlet 5. The induction coil 7 is disposed between the first excitation coil 6 and the second excitation coil 8. In this embodiment, a method for fabricating the three-coil microfluidic chip is provided as follows:

[0061] The first excitation coil 6, induction coil 7, and second excitation coil 8 are arranged side-by-side and passed through a 1300-micron copper wire. They are then fixed onto a fragment and encased in a mold. PDMS and a curing agent are mixed in a 10:1 ratio, and air bubbles are removed using a vacuum drying oven. The PDMS is poured into the mold and then dried in a vacuum drying oven for 30 minutes to cure. After curing, the copper wire is removed, forming a microchannel, thus completing the fabrication of the three-coil microfluidic chip.

[0062] In a preferred embodiment of the present invention, the first excitation coil 6, the second excitation coil 8, and the induction coil 7 are all wound with copper wire with a diameter of 70 μm. The first excitation coil 6 and the second excitation coil 8 are wound in opposite directions, each with 300 turns and an inner diameter of 1300 μm.

[0063] In specific implementation, as a preferred embodiment of the present invention, such as Figure 2 As shown, the first excitation coil 6 and the second excitation coil 8 are connected in parallel at a voltage of U. in On the waveform generator, the two ends of the induction coil 7 are connected to the signal conditioning unit 10. Figure 2 In the diagram, M1 and M2 are excitation coils, and L1 is the induction coil. The excitation signal U... in A sinusoidal signal is generated by a waveform generator. The output induced signal U out It is also a sinusoidal AC signal, which is converted into a DC signal by the signal conditioning circuit, and finally converted into a digital signal by the data acquisition card 11 and stored in the computer. The signal conditioning unit includes a half-wave rectifier circuit 12, a low-pass filter circuit 13, a lock-in amplifier 14, and a post-amplifier 15, which are connected in sequence.

[0064] Example 1

[0065] This invention provides a method for distinguishing and detecting mixed abrasive particles and oils based on the aforementioned mixed abrasive particle oil distinguishing and detecting device, comprising:

[0066] Individual 500μm and 700μm iron particles and 500μm and 700μm copper particles are adhered to ultrafine plastic fibers. A stepper motor controls a slide table to control the reciprocating motion of the particles within a microchannel 3, and the signal from one of the reciprocating motions is captured. Figure 3 As shown, this represents the induced electromotive force generated by four types of particles passing through a three-coil microfluidic chip.

[0067] When a single iron particle passes through the three-coil microfluidic chip, the output signal shows two peaks and two troughs, and the peak and trough signals are different in magnitude, and the signal is symmetrical about the center point;

[0068] When a single copper particle passes through the three-coil microfluidic chip, the output signal shows two peaks and troughs, but the trough signal is obvious and the signal is not symmetrical about the center point.

[0069] Example 2

[0070] This invention provides a method for distinguishing and detecting mixed abrasive particles and oils based on the aforementioned mixed abrasive particle oil distinguishing and detecting device, comprising:

[0071] A 500μm iron particle and a 700μm copper particle are attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. A stepper motor controls a slide to make the particles reciprocate within a microchannel 3, and the signal from one of these reciprocating motions is captured. Figure 4 As shown, this represents the induced electromotive force generated by the particles passing through the three-coil microfluidic chip.

[0072] When the particle spacing is 0mm, since the copper particles enter the excitation coil first, the initial phase is... Figure 3 The copper particles are the same, but when the iron particles enter the excitation coil, only part of the copper particles remain in the excitation coil. Therefore, the copper particles only weaken the peak value of the iron particles. The output signal is similar to that of the copper particles, but it will produce two peaks and three troughs with different amplitudes.

[0073] When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through.

[0074] When the particle spacing is 2mm, the signal will show three peaks and troughs, but the amplitudes are different.

[0075] When the particle spacing is 3mm, the signal will show four peaks and troughs.

[0076] Example 3

[0077] This invention provides a method for distinguishing and detecting mixed abrasive particles and oils based on the aforementioned mixed abrasive particle and oil separation detection device, comprising: attaching a 500μm copper particle and a 700μm iron particle to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm respectively; controlling the particle to reciprocate in a microchannel using a stepper motor-controlled slide table; and capturing the signal from one of the reciprocating motions. Figure 5 As shown, this represents the induced electromotive force generated by the particles passing through the three-coil microfluidic chip.

[0078] When the two particles are 0mm apart, compared to the signal of a single 700μm iron particle, there is only a change in amplitude. At this time, the signal has two peaks and troughs.

[0079] When the particle spacing is 1 mm, the signal will show three peaks and two troughs;

[0080] When the particle spacing is 2mm, the signal will show three peaks and three troughs with different amplitudes.

[0081] When the particle spacing is 3mm, the signal will show three peaks and four troughs.

[0082] Example 4

[0083] This invention provides a method for distinguishing and detecting mixed abrasive particles and oils based on the aforementioned mixed abrasive particle oil distinguishing and detecting device, comprising:

[0084] Two 700μm copper particles were attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. A stepper motor controlled a slide to move the particles reciprocatingly within a microchannel, and the signal from one of the reciprocating motions was captured. Figure 6 As shown, this represents the induced electromotive force generated by the particles passing through the three-coil microfluidic chip.

[0085] When the particle spacing is 0mm, since the sum of the diameters of two 700μm copper particles is 1.4mm and the width of the excitation coil is 1mm, the two copper particles cannot appear in the excitation coil at the same time, so the impact on the signal amplitude is small.

[0086] When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through.

[0087] When the particle spacing is 2mm, the signal will have three peaks and troughs, but their amplitude and signal change trend are different.

[0088] When the particle spacing is 3mm, the signal will show four peaks and troughs.

[0089] Example 5

[0090] This invention provides a method for distinguishing and detecting mixed abrasive particles and oils based on the aforementioned mixed abrasive particle oil distinguishing and detecting device, comprising:

[0091] Two 500μm iron particles were attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. A stepper motor controlled a slide to move the particles reciprocatingly within a microchannel, and the signal from one of the reciprocating motions was captured. Figure 7 As shown, this represents the induced electromotive force generated by the particles passing through the three-coil microfluidic chip.

[0092] When the particle spacing is 0mm, since two 500μm iron particles can appear in the excitation coil at the same time, it has a significant impact on the signal amplitude. The maximum peak value is 400mV and the maximum trough value is 390mV. Two peaks and two troughs will appear. The waveform at this time is similar to the signal generated by a single 700μm iron particle, but the values ​​of the two peaks and troughs are not the same. Therefore, they can be distinguished by the values ​​of the two peaks and troughs.

[0093] When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through.

[0094] When the particle spacing is 2mm, the signal will show three peaks and troughs, but their amplitudes are different.

[0095] When the particle spacing is 3mm, the signal will show four peaks and troughs.

[0096] In summary, the method for distinguishing and detecting mixed abrasive particles in oil detection and analysis proposed in this invention can effectively analyze mixed abrasive particles by analyzing the initial phase, number of peaks and troughs, and amplitude of the signal. This prevents the deviations that traditional sensors may make in analyzing signals based solely on phase and amplitude due to abrasive particle mixing.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for distinguishing and detecting mixed abrasive particles and oil, characterized in that, include: A three-coil microfluidic chip, a signal conditioning unit connected to the three-coil microfluidic chip, and a data acquisition card connected to the signal conditioning unit. The three-coil microfluidic chip, combined with the signal conditioning unit, analyzes the characteristics of overlapping particles by measuring phase, amplitude, and the number of peaks and troughs. The three-coil microfluidic chip includes a glass substrate and a chip body disposed on the glass substrate; the chip body includes an oil inlet, a PDMS substrate, a microchannel, an oil outlet, two excitation coils, and an induction coil; in the chip body: the two excitation coils and the induction coil are respectively wound on the microchannel and are all embedded inside the PDMS substrate, one port of the microchannel serves as the oil inlet, the other port serves as the oil outlet, and the induction coil is disposed between the two excitation coils; The signal conditioning unit includes a half-wave rectifier circuit, a low-pass filter circuit, a lock-in amplifier, and a post-amplifier, which are connected in sequence.

2. The device for distinguishing and detecting mixed abrasive particles and oils according to claim 1, characterized in that, The two excitation coils are wound in opposite directions, with each excitation coil having 300 turns and an inner diameter of 1300 μm.

3. The device for distinguishing and detecting mixed abrasive particles and oils according to claim 1, characterized in that, The two excitation coils are connected in parallel to the waveform generator, and the two ends of the induction coil are connected to the signal conditioning unit.

4. The device for distinguishing and detecting mixed abrasive particles and oils according to claim 3, characterized in that, The induction coil and the two excitation coils are all made of copper wire with a diameter of 70μm.

5. A method for distinguishing and detecting mixed abrasive particles and oils based on the mixed abrasive particle distinguishing and detecting device according to any one of claims 1-4, characterized in that, include: Individual 500μm and 700μm iron particles and 500μm and 700μm copper particles are attached to ultrafine plastic fibers. The particles are reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal of one of the back-and-forth movements is captured. When a single iron particle passes through the three-coil microfluidic chip, the output signal shows two peaks and two troughs, and the peak and trough signals are different in magnitude, and the signal is symmetrical about the center point; When a single copper particle passes through the three-coil microfluidic chip, the output signal shows two peaks and troughs, but the trough signal is obvious and the signal is not symmetrical about the center point.

6. The method for distinguishing and detecting mixed abrasive oils according to claim 5, characterized in that, Also includes: A 500μm iron particle and a 700μm copper particle are attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. The particles are reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal from one of the back-and-forth movements is captured. When the particle spacing is 0mm, the copper particles enter the excitation coil first, so the initial phase is the same as that of the copper particles. When the iron particles enter the excitation coil, only part of the copper particles remain in the excitation coil, so it only weakens the peak value of the iron particles. The output signal is similar to that of the copper particles, but it will produce two peaks and three troughs with different amplitudes. When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through. When the particle spacing is 2mm, the signal will show three peaks and troughs, but the amplitudes are different. When the particle spacing is 3mm, the signal will show four peaks and troughs.

7. The method for distinguishing and detecting mixed abrasive oils according to claim 5, characterized in that, Also includes: A 500μm copper particle and a 700μm iron particle are attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. The particles are reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal from one of the reciprocating motions is captured. When the two particles are 0mm apart, compared to the signal of a single 700μm iron particle, there is only a change in amplitude. At this time, the signal has two peaks and troughs. When the particle spacing is 1 mm, the signal will show three peaks and two troughs; When the particle spacing is 2mm, the signal will show three peaks and three troughs with different amplitudes. When the particle spacing is 3mm, the signal will show three peaks and four troughs.

8. The method for distinguishing and detecting mixed abrasive oils according to claim 5, characterized in that, Also includes: Two 700μm copper particles were attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. The particles were then reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal from one of the reciprocating movements was captured. When the particle spacing is 0mm, since the sum of the diameters of two 700μm copper particles is 1.4mm and the width of the excitation coil is 1mm, the two copper particles cannot appear in the excitation coil at the same time, so the impact on the signal amplitude is small. When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through. When the particle spacing is 2mm, the signal will have three peaks and troughs, but their amplitude and signal change trend are different. When the particle spacing is 3mm, the signal will show four peaks and troughs.

9. The method for distinguishing and detecting mixed abrasive oil particles according to claim 5, characterized in that, Also includes: Two 500μm iron particles were attached to ultrafine plastic fibers at distances of 0mm, 1mm, 2mm, and 3mm, respectively. The particles were then reciprocated in the microchannel by a slide controlled by a stepper motor, and the signal from one of the reciprocating movements was captured. When the particle spacing is 0mm, since two 500μm iron particles can appear in the excitation coil at the same time, it has a significant impact on the signal amplitude. The maximum peak value is 400mV and the maximum trough value is 390mV. Two peaks and two troughs will appear. The waveform at this time is similar to the signal generated by a single 700μm iron particle, but the values ​​of the two peaks and troughs are not the same. Therefore, they can be distinguished by the values ​​of the two peaks and troughs. When the particle spacing is 1mm, the signal amplitude will decrease because two particles will partially appear in two excitation coils at the same time. At this time, the signal will have three peaks and troughs, and the initial phase of particles with the same properties will not change when they pass through. When the particle spacing is 2mm, the signal will show three peaks and troughs, but their amplitudes are different. When the particle spacing is 3mm, the signal will show four peaks and troughs.

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