A method for detecting the mass of ferromagnetic particles based on a magnetic bar sensor

Abstract

This invention relates to a method for detecting the mass of ferromagnetic particles based on a magnetic rod sensor. The magnetic rod sensor has a detection end and a control end with a magnetic rod and an LC resonant circuit. The method includes: when the magnetic rod attracts ferromagnetic particles in oil onto an induction coil, the control end controls the LC resonant circuit to generate a self-excited oscillation signal related to the change in inductance of the winding; the control end analyzes the self-excited oscillation signal to obtain the resonant frequency of the LC resonant circuit, and then calculates the mass of the ferromagnetic particles attracted by the magnetic rod based on the resonant frequency; the control end sends out the calculated ferromagnetic mass as an analog signal or a digital signal. This invention improves detection sensitivity by using a magnetic rod formed by multiple magnets connected in series to form a larger attraction area and attraction magnitude, and by using several coils connected in series with opposite directions to form a winding. The method implemented based on the above-mentioned equipment can promptly understand the wear status of the monitored system or equipment.

Description

Technical Field

[0001] This invention relates to the field of oil monitoring technology, and in particular to a method for detecting the quality of ferromagnetic particles based on a magnetic rod sensor. Background Technology

[0002] In the field of online oil monitoring, the content of ferromagnetic particles in the oil is directly related to equipment wear. Existing equipment and methods for monitoring ferromagnetic particles in oil include electromagnetic ferromagnetic particle sensors and magnetic plug-type ferromagnetic particle sensors.

[0003] Electromagnetic ferromagnetic particle sensors: Oil needs to flow at a certain velocity through the electromagnetic ferromagnetic particle monitoring coil to determine technical parameters such as the mass, quantity, and diameter of ferromagnetic particles in the monitored oil. During the monitoring process, the flow rate and pressure of the oil passing through the electromagnetic ferromagnetic particle coil need to be controlled, resulting in relatively low actual monitoring efficiency. Furthermore, it cannot collect ferromagnetic particles for secondary analysis to determine the source of wear faults. Therefore, electromagnetic ferromagnetic particle sensors are commonly used for wear monitoring in precision equipment.

[0004] Magnetic plug-type ferromagnetic particle sensor: This sensor uses a single circular magnet with a sensing circuit added to the rear of the S or N pole, and is vertically mounted at the bottom of the equipment's oil tank. It can determine the size and mass of ferromagnetic particles. Because it uses a single circular magnet and only one S or N pole can attract ferromagnetic particles, the actual amount of ferromagnetic particles attracted is limited. It is only suitable for small equipment, and the magnetic plug needs to be cleaned frequently to remove the attracted ferromagnetic particles.

[0005] Therefore, measurement methods based on electromagnetic ferromagnetic particle monitoring sensors and magnetic plug ferromagnetic particle monitoring sensors do not provide a suitable solution for heavy or severely worn equipment, which is an urgent issue to be addressed. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for quality detection of ferromagnetic particles based on a magnetic rod sensor, which solves the technical problem that the existing equipment oil monitoring technology has high application conditions, low monitoring efficiency and too many restrictions, and does not provide a suitable oil monitoring solution for heavy or severely worn equipment.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0010] In a first aspect, embodiments of the present invention provide a method for mass detection of ferromagnetic particles based on a magnetic rod sensor. The magnetic rod sensor has a detection end and a control end with a magnetic rod and an LC resonant circuit. The magnetic rod is composed of several permanent magnets connected in series. The LC resonant circuit includes a winding wound around the magnetic rod. The winding includes an induction coil wound on each permanent magnet. Every two adjacent induction coils are wound in opposite directions, and all induction coils are connected in series. The method includes:

[0011] When the magnetic rod attracts ferromagnetic particles in the oil onto the induction coil, the control terminal controls the LC resonant circuit to generate a self-excited oscillation signal related to the change in inductance of the winding.

[0012] The control terminal analyzes the self-excited oscillation signal to obtain the resonant frequency of the LC resonant circuit, and then calculates the mass of the ferromagnetic particles adsorbed by the magnetic rod based on the resonant frequency. The control terminal sends out the calculated ferromagnetic mass in the form of an analog signal or a digital signal.

[0013] Among them, the frequency of the self-excited oscillation signal is negatively correlated with the inductance of the winding, and the inductance of the winding is positively correlated with the mass of the ferromagnetic particles adsorbed by the magnetic rod. As the mass of the adsorbed ferromagnetic particles increases, the permeability of the winding within the set space range increases, resulting in an increase in the inductance of the winding and a decrease in the resonant frequency.

[0014] Optionally, the mass of the ferromagnetic particles adsorbed by the magnetic rod can be obtained using a mass formula, which is:

[0015] G = Af 3 +Bf 2 +Cf+D;

[0016] Where G represents the mass of the ferromagnetic particle, f represents the resonant frequency, and A, B, C, and D are structural coefficients, with A ranging from 12.8 to 13.8, B ranging from 454.3 to 455.3, C ranging from 5268.3 to 5269.3, and D ranging from 387930.3 to 387931.3.

[0017] Optionally, the control terminal analyzes the self-excited oscillation signal to obtain the resonant frequency of the LC resonant circuit, and then calculates the mass of the ferromagnetic particles adsorbed by the magnetic rod based on the resonant frequency. Before the control terminal sends out the calculated ferromagnetic mass in the form of an analog signal or a digital signal, it also includes:

[0018] By using an adder circuit pre-set between the LC resonant circuit and the control terminal, the amplitude of the resonant waveform in the LC oscillation circuit is increased by 0.5V without changing the frequency value, thus obtaining a pre-processed self-excited oscillation signal.

[0019] By using an adder circuit pre-set between the adder circuit and the control terminal, the waveform of the pre-processed self-excited oscillation signal is converted from a sine wave to a square wave without changing the resonant frequency. Finally, the square wave self-excited oscillation signal, after further processing, is sent to the main controller for processing.

[0020] Optionally, the LC resonant circuit includes: an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, an eleventh resistor, a twelfth resistor, and an eleventh transistor;

[0021] The collector of the first transistor is connected to the induction coil on the first end of the magnetic rod and the second end of the thirteenth capacitor.

[0022] The base of the first transistor is connected to the second terminal of the twelfth resistor and the second terminal of the twelfth capacitor;

[0023] The emitter of the first transistor is connected to the second terminal of the eleventh capacitor, the first terminal of the thirteenth capacitor, and the second terminal of the eleventh resistor. The first terminal of the eleventh resistor is connected to the 3.3V voltage terminal.

[0024] The induction coil on the second end of the magnetic rod, the first end of the eleventh capacitor, the first end of the twelfth capacitor, and the first end of the twelfth resistor are all grounded.

[0025] Optionally,

[0026] The adder circuit includes: a 21st capacitor, a 22nd capacitor, a 21st resistor, a 22nd resistor, a 23rd resistor, a 24th resistor, a 25th resistor, a 26th resistor, a 27th resistor, and an operational amplifier. The non-inverting input of the operational amplifier is connected to the second terminals of the 23rd and 24th resistors. The first terminal of the 24th resistor is connected to the collector of the first transistor, the induction coil on the first end of the ferrite rod, and the second terminal of the 13th capacitor. The first terminal of the 23rd resistor is connected to the second terminals of the 21st, 22nd, and 21st capacitors. The first terminal of the 21st resistor is connected to a 3.3V voltage terminal. The first terminals of the 22nd resistor and the 21st capacitor are grounded. The inverting input of the operational amplifier is connected to the first terminals of the 25th and 26th resistors. The second terminal of the 25th resistor is grounded. The positive power input of the operational amplifier is connected to the 3.3V voltage terminal and the first terminal of the 22nd capacitor. The second terminal of the 22nd capacitor is grounded. The negative power input of the operational amplifier is grounded. The output of the operational amplifier is connected to the second terminal of the 26th resistor and the first terminal of the 27th resistor.

[0027] The comparator circuit includes: a 31st capacitor, a 32nd capacitor, a 31st resistor, a 32nd resistor, a 33rd resistor, a 34th resistor, a series diode, and a comparator chip. The non-inverting input of the comparator chip is connected to the second terminal of the 31st resistor, the second terminal of the 32nd resistor, and the second terminal of the 31st capacitor. The first terminal of the 31st resistor is connected to a 3.3V voltage terminal. The first terminals of the 32nd resistor and the first terminal of the 31st capacitor are grounded. The negative input of the comparator chip is grounded. The inverting input of the comparator chip is connected to the second terminal of the 27th resistor. The positive input of the comparator chip is connected to the 3.3V voltage terminal, the second terminal of the 32nd capacitor, the first terminal of the 34th resistor, and the cathode of the first diode of the series diode. The first terminal of the 32nd capacitor and the anode of the second diode of the series diode are grounded. The output of the comparator chip is connected to the first terminal of the 33rd resistor. The second terminal of the 33rd resistor is connected to the second terminal of the 34th resistor, the series connection of the first and second diodes of the series diode, and the measurement port of the main controller.

[0028] Optionally, the opposite faces of adjacent permanent magnets have the same polarity.

[0029] Alternatively, the permanent magnet may be a circular magnet with a hole.

[0030] Optionally, the diameter of the magnetic rod is 13-15 mm and the height is 32-34 mm.

[0031] Optionally, the detection end includes a polyetheretherketone (PEEK) housing covering the magnetic rod and windings.

[0032] Optionally, the control unit includes: a connector, a housing, and a main controller;

[0033] The connectors include the power positive and negative interfaces, the 485 communication port, and the power communication interface for grounding, which are respectively connected to the main controller via wire harnesses.

[0034] The housing is configured with a cavity to accommodate the main controller, one end of the housing abuts against a magnetic rod, and the other end of the housing abuts against a connector.

[0035] (III) Beneficial Effects

[0036] The beneficial effects of this invention are as follows: This invention utilizes a magnetic rod formed by multiple magnets connected in series to create a larger adsorption area and a greater adsorption capacity, and employs several coils connected in series with opposite directions to form a winding, thereby improving detection sensitivity. The monitoring method based on the above-mentioned device utilizes the magnetic rod to adsorb ferromagnetic particles in the oil onto the outside of the coil. The adsorbed ferromagnetic particles change the inductance of the coil, thereby causing a change in the LC resonant frequency. The mass of the adsorbed ferromagnetic particles is measured by measuring the change in the LC resonant frequency. This method leverages the advantages of the device provided by this invention to accurately and in real-time understand the wear status of the monitored system or equipment, enabling timely early warning of abnormal wear. Attached Figure Description

[0037] Figure 1 A schematic flowchart of a method for detecting the quality of ferromagnetic particles based on a magnetic rod sensor provided by the present invention;

[0038] Figure 2 The circuit principles of the LC resonant circuit, the adder circuit, and the comparator circuit of the ferromagnetic particle mass detection method based on the magnetic rod sensor provided by the present invention.

[0039] Figure 3 A schematic diagram of a magnetic rod and a coil for a method of detecting the quality of ferromagnetic particles based on a magnetic rod sensor provided by the present invention;

[0040] Figure 4 A schematic diagram of the structure of a magnetic rod sensor for a method of mass detection of ferromagnetic particles based on a magnetic rod sensor provided by the present invention;

[0041] Figure 5 This invention provides a schematic diagram of the frequency and adsorbed particle mass in a method for detecting the mass of ferromagnetic particles based on a magnetic rod sensor.

[0042] [Explanation of Labels in the Attached Image]

[0043] 1: Induction coil;

[0044] 2: Permanent magnet;

[0045] 3: Polyetheretherketone (PEEK) shell;

[0046] 4: Main controller;

[0047] 5: Connector. Detailed Implementation

[0048] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] like Figure 1As shown in the embodiment of the present invention, a method for quality detection of ferromagnetic particles based on a magnetic rod sensor is characterized in that the magnetic rod sensor has a detection end and a control end with a magnetic rod and an LC resonant circuit. The magnetic rod is composed of several permanent magnets 2 connected in series. The LC resonant circuit includes a winding wound around the magnetic rod, and the winding includes an induction coil 1 wound on each permanent magnet 2. Every two adjacent induction coils 1 are wound in opposite directions, and all induction coils 1 are connected in series. The method includes: when the magnetic rod attracts ferromagnetic particles in the oil to the induction coil 1, the control end controls the LC resonant circuit to generate a self-excited oscillation related to the change in inductance of the winding. The control terminal analyzes the self-excited oscillation signal to obtain the resonant frequency of the LC resonant circuit, and then calculates the mass of the ferromagnetic particles adsorbed by the magnetic rod based on the resonant frequency. The control terminal sends out the calculated ferromagnetic mass as an analog signal or a digital signal. Among them, the frequency of the self-excited oscillation signal is negatively correlated with the inductance of the winding, the inductance of the winding is positively correlated with the mass of the ferromagnetic particles adsorbed by the magnetic rod, and the LC resonant frequency has a high-order relationship with the mass of the ferromagnetic particles adsorbed by the magnetic rod. As the mass of the adsorbed ferromagnetic particles increases, the permeability within the set space range of the winding increases, resulting in an increase in the inductance of the winding and a decrease in the resonant frequency.

[0050] This invention improves detection sensitivity by using a magnetic rod formed by multiple magnets connected in series to create a larger adsorption area and a greater adsorption capacity, and by using several coils connected in series with opposite directions to form a winding. The monitoring method based on this device utilizes the magnetic rod to adsorb ferromagnetic particles in the oil onto the outside of the coil. The adsorbed ferromagnetic particles change the inductance of the coil, thereby causing a change in the LC resonant frequency. The mass of the adsorbed ferromagnetic particles is measured by measuring the change in the LC resonant frequency. This method leverages the advantages of the device provided by this invention to accurately and in real-time understand the wear status of the monitored system or equipment, enabling timely early warning of abnormal wear.

[0051] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0052] Furthermore, the mass of the ferromagnetic particles adsorbed by the magnetic rod is obtained using the mass formula, which is:

[0053] G = Af 3 +Bf 2 +Cf+D;

[0054] Where G represents the mass of the ferromagnetic particle, f represents the resonant frequency, and A, B, C, and D are structural coefficients. The values ​​of A range from 12.8 to 13.8, B from 454.3 to 455.3, C from 5268.3 to 5269.3, and D from 387930.3 to 387931.3. These coefficients A, B, C, and D are related to the structural dimensions of the magnetic rod and the relevant parameters of the detection circuit.

[0055] Furthermore, the control terminal analyzes the self-excited oscillation signal to obtain the resonant frequency of the LC resonant circuit, and then calculates the mass of the ferromagnetic particles adsorbed by the magnetic rod based on the resonant frequency. Before the control terminal sends out the calculated ferromagnetic mass as an analog or digital signal, it also includes:

[0056] By using an adder circuit pre-set between the LC resonant circuit and the control terminal, the amplitude of the resonant waveform in the LC oscillation circuit is increased by 0.5V without changing the frequency value, thus obtaining a pre-processed self-excited oscillation signal.

[0057] By using an adder circuit pre-set between the adder circuit and the control terminal, the waveform of the pre-processed self-excited oscillation signal is converted from a sine wave to a square wave without changing the resonant frequency. Finally, the square wave self-excited oscillation signal, after further processing, is sent to the main controller 4 for further processing.

[0058] refer to Figure 2 The LC resonant circuit includes: an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, an eleventh resistor, a twelfth resistor, and an eleventh transistor. The collector of the first transistor is connected to the induction coil 1 on the first end of the magnetic rod and the second terminal of the thirteenth capacitor. The base of the first transistor is connected to the second terminal of the twelfth resistor and the second terminal of the twelfth capacitor. The emitter of the first transistor is connected to the second terminal of the eleventh capacitor, the first terminal of the thirteenth capacitor, and the second terminal of the eleventh resistor. The first terminal of the eleventh resistor is connected to a 3.3V voltage terminal. The induction coil 1 on the second end of the magnetic rod, the first terminal of the eleventh capacitor, the first terminal of the twelfth capacitor, and the first terminal of the twelfth resistor are all grounded. When a particle is attracted to the coil of the magnetic rod, the inductance of the corresponding coil 1L1 changes, which in turn changes the LC oscillation circuit, resulting in a change in the resonant frequency of the LC oscillation circuit.

[0059] However, the self-excited oscillation signal generated by the LC resonant circuit still needs to be conditioned before being sent to the frequency measurement port of the main controller 4. Therefore, the magnetic rod sensor also includes an adder circuit and a comparator circuit located between the LC resonant circuit and the measurement port of the main controller 4. The adder circuit is used to increase the amplitude of the resonant waveform in the LC oscillation circuit by 0.5V without changing the frequency value, providing a suitable resonant waveform for processing by the subsequent circuits. The comparator circuit is used to convert the waveform from a sine wave to a square wave without changing the resonant frequency, and finally send the square wave to the main controller 4.

[0060] Specifically, refer to Figure 2 The adder circuit includes: a 21st capacitor, a 22nd capacitor, a 21st resistor, a 22nd resistor, a 23rd resistor, a 24th resistor, a 25th resistor, a 26th resistor, a 27th resistor, and an operational amplifier. The non-inverting input of the operational amplifier is connected to the second terminals of the 23rd and 24th resistors. The first terminal of the 24th resistor is connected to the collector of the first transistor, the induction coil 1 on the first end of the ferrite rod, and the second terminal of the 13th capacitor. The first terminal of the 23rd resistor is connected to the second terminals of the 21st, 22nd, and 21st capacitors. The first terminal of the 21st resistor is connected to a 3.3V voltage terminal. The first terminals of the 22nd resistor and the 21st capacitor are grounded. The inverting input of the operational amplifier is connected to the first terminals of the 25th and 26th resistors. The second terminal of the 25th resistor is grounded. The positive input of the operational amplifier is connected to the 3.3V voltage terminal and the first terminal of the 22nd capacitor. The second terminal of the 22nd capacitor is grounded. The negative input of the operational amplifier is grounded. The output of the operational amplifier is connected to the second terminal of the 26th resistor and the first terminal of the 27th resistor.

[0061] The comparator circuit includes: a 31st capacitor, a 32nd capacitor, a 31st resistor, a 32nd resistor, a 33rd resistor, a 34th resistor, a series diode, and a comparator chip. The non-inverting input of the comparator chip is connected to the second terminal of the 31st resistor, the second terminal of the 32nd resistor, and the second terminal of the 31st capacitor. The first terminal of the 31st resistor is connected to a 3.3V voltage terminal. The first terminals of the 32nd resistor and the first terminal of the 31st capacitor are grounded. The negative input of the comparator chip is grounded. The inverting input of the comparator chip is connected to the second terminal of the 27th resistor. The positive input of the comparator chip is connected to the 3.3V voltage terminal, the second terminal of the 32nd capacitor, the first terminal of the 34th resistor, and the negative terminal of the first diode of the series diode. The first terminal of the 32nd capacitor and the positive terminal of the second diode of the series diode are grounded. The output of the comparator chip is connected to the first terminal of the 33rd resistor. The second terminal of the 33rd resistor is connected to the second terminal of the 34th resistor, the series terminal of the first and second diodes of the series diode, and the measurement port of the main controller 4.

[0062] refer to Figure 3 A coil is wound on each permanent magnet 2, with adjacent coils wound in opposite directions. The purpose of connecting the coils in series to form a winding is to keep the alternating magnetic field generated by the self-excited oscillation of the winding as closely as possible to the magnetic field generated by the permanent magnet 2, so that the ferromagnetic particles attracted by the magnetic rod can change the inductance of the winding to the maximum extent, thereby improving the measurement sensitivity.

[0063] Also refer to Figure 3 The opposing surfaces of adjacent permanent magnets 2 have the same polarity. This ensures a suitable magnetic field loop, maximizing the adsorption of particles by the permanent magnets 2. Furthermore, considering that multiple ring magnets connected in series have a larger adsorption capacity, the permanent magnets 2 are circular magnets with holes. Preferably, the diameter of the magnetic rod is 13–15 mm, and the height is 32–34 mm.

[0064] Then, refer to Figure 4 The magnetic rod sensor also includes a polyetheretherketone (PEEK) housing 3, which is a protective shell added around the permanent magnet 2 and the induction coil 1 to prevent oil and water from seeping in.

[0065] Furthermore, the magnetic rod sensor also includes: connector 5, housing, and main controller 4. Connector 5 includes a power supply positive and negative interface, a 485 communication port, and a power communication interface for grounding the main controller 4, which are respectively connected to the main controller 4 via wiring harnesses. The housing is configured with a cavity to accommodate the main controller 4, with one end of the housing abutting against the magnetic rod and the other end of the housing abutting against connector 5.

[0066] The self-excited oscillation signal generated by the LC resonant circuit is conditioned and sent to the frequency measurement port of the main controller 4. The main controller 4 measures the frequency and calculates the mass of the adsorbed ferromagnetic particles. The main controller 4 extracts and processes the changes on the induction coil 1, converts them into digital signals, and finally transmits the data via RS-485 communication.

[0067] In one specific embodiment, such as Figure 4 As shown, the winding method of the magnetic rod and induction coil 1 at the detection end is as follows:

[0068] Step 1: Select a magnetic rod with a diameter of 14mm and a height of 33mm, and select 0.2mm enameled wire;

[0069] Step 2: After placing the coil holder on the magnetic rod, press... Figure 1 The method involves winding alternating positive and negative coils on a coil frame;

[0070] Step 3: After winding the induction coil 1, lead out the first and last enameled wires and then put a polyetheretherketone shell on the coil frame.

[0071] refer to Figure 2 By designing the corresponding PCB board based on the circuit schematic, it can be visually observed using an oscilloscope that the square wave output frequency of the corresponding LC resonant circuit changes when ferromagnetic particles are brought close to the magnetic rod induction coil 1. The relationship between frequency and the mass of the adsorbed particles can then be obtained using the above method. Figure 5 .

[0072] It is worth mentioning that the main controller 4 is a general-purpose control chip, including any one of the following: microcontroller, FPGA, CPLD and DSP.

[0073] In summary, this invention provides a magnetic rod sensor and a method for detecting the quality of ferromagnetic particles based on the magnetic rod sensor. To solve the problem of detecting the quality (quantity) of ferromagnetic particles adsorbed on magnetic rods and magnetic filters, the magnetic rod sensor provided by this invention includes a magnetic rod, a winding wound around the magnetic rod, an LC resonant circuit, and a main controller 4. The magnetic rod is composed of several permanent magnets 2 mounted in series with the same polarity opposite each other. A coil is wound on each permanent magnet 2, with adjacent coils wound in opposite directions. The coils are connected in series to form a winding, and the winding and capacitor constitute an LC resonant circuit. The magnetic rod adsorbs ferromagnetic particles in the oil onto the outside of the coil. The adsorbed ferromagnetic particles will change the inductance of the coil, thereby causing a change in the LC resonant frequency.

[0074] This invention utilizes a magnetic rod composed of multiple magnets connected in series to create a larger adsorption area and a greater adsorption capacity. Due to its larger adsorption area, it can achieve excellent ferromagnetic particle capture efficiency simply by being installed directly in the equipment's oil without any special adjustments. By utilizing the weight of ferromagnetic particles, a crucial parameter for monitoring mechanical equipment faults, faults can be detected quickly and effectively. Furthermore, the winding consists of several coils connected in series with opposite directions, ensuring that the electromagnetic field of each sub-coil coincides as closely as possible with the magnetic field of the magnetic rod, thus improving detection sensitivity and efficiency. Compared to magnetic plug sensors, the sensor provided by this invention can be installed in all directions, including vertical and horizontal installation positions.

[0075] The quality testing method is as follows: a magnetic rod attracts ferromagnetic particles in the oil to the outside of the coil. The attracted ferromagnetic particles will change the inductance of the coil, thereby causing a change in the LC resonant frequency. The mass of the attracted ferromagnetic particles is measured by measuring the change in the LC resonant frequency.

[0076] Therefore, this invention fills the gap in oil monitoring solutions for heavy or severely worn equipment. By using the detection method based on the aforementioned sensors, the wear status of the monitored system (or equipment) can be understood, and early warnings can be given for abnormal wear. It can also monitor the working status of magnetic filters, rationally arrange the cleaning (or backflushing) time of magnetic filters, reduce production costs, and has practical application significance.

[0077] Since the systems / devices described in the above embodiments of the present invention are systems / devices used to implement the methods of the above embodiments of the present invention, those skilled in the art can understand the specific structure and modifications of the systems / devices based on the methods described in the above embodiments of the present invention, and therefore will not be repeated here. All systems / devices used in the methods of the above embodiments of the present invention fall within the scope of protection of the present invention.

[0078] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0079] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions.

[0080] It should be noted that any reference numerals placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In claims that enumerate several means, several of these means may be embodied by the same hardware. The use of the terms first, second, third, etc., is merely for convenience of expression and does not indicate any order. These terms can be understood as part of the component names.

[0081] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0082] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the claims should be interpreted to include both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0083] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, then this invention should also include these modifications and variations.

Claims

1. A method for quality detection of ferromagnetic particles based on a magnetic rod sensor, characterized in that, The magnetic rod sensor has a detection end and a control end with a magnetic rod and an LC resonant circuit. The magnetic rod is composed of several permanent magnets connected in series. The LC resonant circuit includes a winding wound around the magnetic rod. The winding includes an induction coil wound on each permanent magnet. Every two adjacent induction coils are wound in opposite directions, and all induction coils are connected in series. The method includes: When the magnetic rod attracts ferromagnetic particles in the oil onto the induction coil, the control terminal controls the LC resonant circuit to generate a self-excited oscillation signal related to the change in inductance of the winding. The control terminal analyzes the self-excited oscillation signal to obtain the resonant frequency of the LC resonant circuit, and then calculates the mass of the ferromagnetic particles adsorbed by the magnetic rod based on the resonant frequency and the mass formula. The control terminal sends out the obtained ferromagnetic mass in the form of an analog signal or a digital signal. Among them, the frequency of the self-excited oscillation signal is negatively correlated with the inductance of the winding, and the inductance of the winding is positively correlated with the mass of the ferromagnetic particles adsorbed by the magnetic rod. As the mass of the adsorbed ferromagnetic particles increases, the permeability of the winding within the set space range increases, resulting in an increase in the inductance of the winding and a decrease in the resonant frequency. The mass formula is: G = Af 3 +Bf 2 +Cf+D; Where G represents the mass of the ferromagnetic particle, f represents the resonant frequency, and A, B, C, and D are structural coefficients, with A ranging from 12.8 to 13.8, B ranging from 454.3 to 455.3, C ranging from 5268.3 to 5269.3, and D ranging from 387930.3 to 387931.

3.

2. The method for quality detection of ferromagnetic particles based on a magnetic rod sensor as described in claim 1, characterized in that, The control unit analyzes the self-excited oscillation signal to obtain the resonant frequency of the LC resonant circuit, and then calculates the mass of the ferromagnetic particles adsorbed by the magnetic rod using the mass formula based on the resonant frequency. Before the control unit sends out the calculated ferromagnetic mass as an analog or digital signal, the following steps are also included: By using an adder circuit pre-set between the LC resonant circuit and the control terminal, the amplitude of the resonant waveform in the LC oscillation circuit is increased by 0.5V without changing the frequency value, thus obtaining a pre-processed self-excited oscillation signal. By using an adder circuit pre-set between the adder circuit and the control terminal, the waveform of the pre-processed self-excited oscillation signal is converted from a sine wave to a square wave without changing the resonant frequency. Finally, the square wave self-excited oscillation signal, after further processing, is sent to the main controller for processing.

3. The method for quality detection of ferromagnetic particles based on a magnetic rod sensor as described in claim 2, characterized in that, The LC resonant circuit includes: an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, an eleventh resistor, a twelfth resistor, and a first transistor; The collector of the first transistor is connected to the induction coil on the first end of the magnetic rod and the second end of the thirteenth capacitor. The base of the first transistor is connected to the second terminal of the twelfth resistor and the second terminal of the twelfth capacitor; The emitter of the first transistor is connected to the second terminal of the eleventh capacitor, the first terminal of the thirteenth capacitor, and the second terminal of the eleventh resistor. The first terminal of the eleventh resistor is connected to the 3.3V voltage terminal. The induction coil on the second end of the magnetic rod, the first end of the eleventh capacitor, the first end of the twelfth capacitor, and the first end of the twelfth resistor are all grounded.

4. The method for quality detection of ferromagnetic particles based on a magnetic rod sensor as described in claim 3, characterized in that, The adder circuit includes: a 21st capacitor, a 22nd capacitor, a 21st resistor, a 22nd resistor, a 23rd resistor, a 24th resistor, a 25th resistor, a 26th resistor, a 27th resistor, and an operational amplifier. The non-inverting input of the operational amplifier is connected to the second terminals of the 23rd and 24th resistors. The first terminal of the 24th resistor is connected to the collector of the first transistor, the induction coil on the first end of the ferrite rod, and the second terminal of the 13th capacitor. The first terminal of the 23rd resistor is connected to the second terminals of the 21st, 22nd, and 21st capacitors. The first terminal of the 21st resistor is connected to a 3.3V voltage terminal. The first terminals of the 22nd resistor and the 21st capacitor are grounded. The inverting input of the operational amplifier is connected to the first terminals of the 25th and 26th resistors. The second terminal of the 25th resistor is grounded. The positive power input of the operational amplifier is connected to the 3.3V voltage terminal and the first terminal of the 22nd capacitor. The second terminal of the 22nd capacitor is grounded. The negative power input of the operational amplifier is grounded. The output of the operational amplifier is connected to the second terminal of the 26th resistor and the first terminal of the 27th resistor. The comparator circuit includes: a 31st capacitor, a 32nd capacitor, a 31st resistor, a 32nd resistor, a 33rd resistor, a 34th resistor, a series diode, and a comparator chip. The non-inverting input of the comparator chip is connected to the second terminal of the 31st resistor, the second terminal of the 32nd resistor, and the second terminal of the 31st capacitor. The first terminal of the 31st resistor is connected to a 3.3V voltage terminal. The first terminals of the 32nd resistor and the first terminal of the 31st capacitor are grounded. The negative input of the comparator chip is grounded. The inverting input of the comparator chip is connected to the second terminal of the 27th resistor. The positive input of the comparator chip is connected to the 3.3V voltage terminal, the second terminal of the 32nd capacitor, the first terminal of the 34th resistor, and the cathode of the first diode of the series diode. The first terminal of the 32nd capacitor and the anode of the second diode of the series diode are grounded. The output of the comparator chip is connected to the first terminal of the 33rd resistor. The second terminal of the 33rd resistor is connected to the second terminal of the 34th resistor, the series connection of the first and second diodes of the series diode, and the measurement port of the main controller.

5. The method for quality detection of ferromagnetic particles based on a magnetic rod sensor as described in any one of claims 1-4, characterized in that, The opposite surfaces of adjacent permanent magnets have the same polarity.

6. The method for quality detection of ferromagnetic particles based on a magnetic rod sensor as described in any one of claims 1-4, characterized in that, The permanent magnet uses a circular magnet with a hole.

7. The method for quality detection of ferromagnetic particles based on a magnetic rod sensor as described in any one of claims 1-4, characterized in that, The diameter of the magnetic rod is 13~15mm and the height is 32~34mm.

8. The method for quality detection of ferromagnetic particles based on a magnetic rod sensor as described in any one of claims 1-4, characterized in that, The detection end includes a polyetheretherketone (PEEK) shell covering the magnetic rod and windings.

9. The method for quality detection of ferromagnetic particles based on a magnetic rod sensor as described in any one of claims 1-4, characterized in that, The control terminal includes: Connectors, housing, and main controller; The connectors include the power positive and negative interfaces, the 485 communication port, and the power communication interface for grounding, which are respectively connected to the main controller via wire harnesses. The housing is configured with a cavity to accommodate the main controller, one end of the housing abuts against a magnetic rod, and the other end of the housing abuts against a connector.

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