An electronic working switch, a magnetic particle flaw detector starting circuit, and a magnetic particle flaw detector.

Abstract

This utility model discloses an electronic working switch, a magnetic particle flaw detector starting circuit, and a magnetic particle flaw detector. The electronic working switch includes: a switch housing, a magnetic field sensor, a magnetic structure, and a magnetic shielding structure. The switch housing has an accommodating space for accommodating the magnetic shielding structure. The magnetic field sensor is disposed on the side wall of the switch housing, and the magnetic structure is disposed on the side wall and opposite to the magnetic field sensor. The magnetic shielding structure is slidably disposed in the accommodating space inside the switch housing to isolate the magnetic field between the magnetic structure and the magnetic field sensor. The electronic working switch in this application converts the positional change of the magnetic shielding structure relative to the magnetic field sensor into a change in the working signal output of the working switch, reducing wear and failure problems caused by mechanical contact and improving measurement accuracy and stability.

Description

Technical Field

[0001] This utility model relates to the field of magnetic particle inspection technology, and in particular to an electronic working switch, a magnetic particle inspection instrument start-up circuit, and a magnetic particle inspection instrument. Background Technology

[0002] Magnetic particle testing is an instrument used to inspect surface and near-surface defects in ferrous products. A magnetic field is applied to the workpiece using a magnetic particle tester, and then a magnetic suspending liquid containing iron powder particles is sprayed onto the workpiece surface. If there are no defects near the workpiece surface, the workpiece acts as a single magnet. If there are defects near the workpiece surface, it's as if the entire magnet splits into S and N poles at the defect location. The magnetic powder particles sprayed onto the workpiece surface are attracted to the defect, magnifying the defect image and forming an indicator pattern, thus achieving non-destructive testing. Therefore, magnetic particle testing is widely used in the manufacturing, installation, and use of pressure vessels (boilers, gas tanks, oil tanks, etc.), pressure pipelines (gas pipes, oil pipes, water pipes), ships, steel, machinery equipment, aerospace, aviation, power, automobiles, motorcycles, petroleum, chemicals, railways, bridges, elevators, amusement parks, etc.

[0003] In existing technologies, magnetic particle flaw detectors typically employ mechanical switches, controlling their operation by turning mechanical contacts on or off. During use, these detectors operate under extremely harsh conditions, requiring the application of a magnetized electric field to the workpiece at the inspection location, the spraying of magnetic suspension upwards, and observation of any buildup. Because the mechanical switches are not completely sealed and waterproof, the magnetic suspension gradually seeps into the detector and corrodes the mechanical contacts, causing wear and failure of the internal contacts. This results in a high failure rate for the operating switches in existing magnetic particle flaw detectors, impacting their detection sensitivity and efficiency.

[0004] Therefore, existing technologies still need to be improved and developed. Utility Model Content

[0005] In view of the shortcomings of the prior art, the purpose of this utility model is to provide an electronic working switch, a magnetic particle flaw detector starting circuit and a magnetic particle flaw detector, in order to solve the problem that the working switch in the prior art is based on a mechanical switch, resulting in poor sealing and easy damage due to failure of the mechanical contacts in contact with the magnetic suspension fluid.

[0006] The technical solution of this utility model is as follows:

[0007] In a first aspect, this application provides an electronic operating switch, comprising: a switch housing, a magnetic field sensor, a magnetic structure, and a magnetic shielding structure; wherein...

[0008] The switch housing has an accommodating space for accommodating the magnetic shielding structure;

[0009] The magnetic field sensor is mounted on the side wall of the switch housing and is connected to an external circuit via a signal line.

[0010] The magnetic structure is disposed on the side wall and is positioned opposite to the magnetic field sensor.

[0011] The magnetic shielding structure is slidably disposed in the accommodating space inside the switch housing to isolate the magnetic field between the magnetic structure and the magnetic field sensor.

[0012] In a further embodiment of this invention, the magnetic shielding structure includes a magnetic shielding block and a keycap, with one end of the magnetic shielding block fixedly connected to the keycap.

[0013] The button cap is used to drive the magnetic shielding part to slide within the accommodating space inside the switch housing.

[0014] In a further embodiment of this invention, the switch housing has a through hole of a first diameter at the corresponding position of the button cap, and the button cap extends out of the switch housing through the through hole.

[0015] In a further embodiment of this invention, the electronic working switch also includes a reset structure. One end of the reset structure is fixedly connected to the end of the accommodating space away from the through hole, and the other end of the reset structure is fixedly connected to the magnetic shielding structure. The reset structure is an elastic reset structure, used to drive the magnetic shielding structure to reset between the magnetic field sensor and the magnetic structure.

[0016] In a further embodiment of this invention, the end of the button cap near the magnetic shielding part has a limiting part with a diameter greater than or equal to the first aperture. When the magnetic shielding part is located between the magnetic field sensor and the magnetic structure, the limiting part abuts against the bottom end of the switch housing.

[0017] A further feature of this invention is that an annular sealing ring is provided around the through hole, and the sealing ring is interference-fitted with the button cap to fill the gap between the button cap and the through hole.

[0018] Secondly, this utility model also provides a starting circuit for a magnetic particle flaw detector, which includes an electronic working switch, a comparison amplification circuit, and a switch status indication circuit as described above; wherein,

[0019] The voltage terminal of the electronic working switch is connected to the working voltage. The electronic working switch is used to generate a switching signal according to the position of the magnetic shielding structure. The switching signal is a working stop signal or a working start signal. The position refers to whether the magnetic shielding structure is located between the magnetic field sensor and the magnetic structure or whether the magnetic shielding structure is not located between the magnetic field sensor and the magnetic structure.

[0020] The comparator amplifier circuit is connected to the signal output terminal of the electronic working switch and is used to receive the switch signal in the electronic working switch. When the switch signal is a working on signal, the comparator amplifier circuit outputs a high-level signal to the signal output terminal of the electronic working switch; when the switch signal is a working off signal, the comparator amplifier circuit outputs a low-level signal to the signal output terminal of the electronic working switch.

[0021] One end of the switch status indicator circuit is connected to the comparator amplifier circuit, and the other end of the switch status indicator circuit is connected to the working circuit. The switch status indicator circuit is used to receive the high-level signal or the low-level signal and convert it into a working start / stop signal to indicate the working status to the working circuit.

[0022] In a further embodiment of this invention, the magnetic particle flaw detector's start-up circuit further includes a first filter circuit and a second filter circuit, wherein...

[0023] The first filter circuit is connected to the common terminal of the electronic working switch and the working voltage, and the first filter circuit is used to perform high-frequency filtering on the working voltage.

[0024] The second filter circuit is connected to the common terminal of the signal output terminal of the electronic working switch and the comparison amplifier circuit. The second filter circuit is used to perform high-frequency filtering on the switching signal output by the magnetic field sensor.

[0025] Thirdly, this application also provides a magnetic particle flaw detector, wherein the magnetic particle flaw detector is provided with an electronic working switch as described above.

[0026] This application provides an electronic working switch, a magnetic particle flaw detector starting circuit, and a magnetic particle flaw detector. The electronic working switch includes: a switch housing, a magnetic field sensor, a magnetic structure, and a magnetic shielding structure. The switch housing has an accommodating space for housing the magnetic shielding structure. The magnetic field sensor is disposed on the side wall of the switch housing and connected to an external circuit via a signal line. The magnetic structure is disposed on the side wall and opposite to the magnetic field sensor. The magnetic shielding structure is slidably disposed within the accommodating space inside the switch housing to isolate the magnetic field between the magnetic structure and the magnetic field sensor. The electronic working switch of this application converts the positional change of the magnetic shielding structure relative to the magnetic field sensor into a change in the working signal output of the working switch, reducing wear and failure problems caused by mechanical contact and improving measurement accuracy and stability. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram illustrating the working principle of the magnetic field sensor in this application.

[0029] Figure 2 This is a schematic diagram of the structure of the electronic working switch in a preferred embodiment of this utility model.

[0030] Figure 3 This is a circuit diagram of the starting circuit of the magnetic particle flaw detector in this utility model.

[0031] The markings in the attached diagram are as follows: 10, switch housing; 11, accommodating space; 20, magnetic field sensor; 21, signal line; 30, magnetic structure; 40, magnetic shielding structure; 41, magnetic shielding part; 42, keycap; 43, limiting part; 50, reset structure; 60, annular sealing ring; 200, comparison amplifier circuit; 300, switch status indicator circuit; 400, first filter circuit; 500, second filter circuit. Detailed Implementation

[0032] This utility model provides an electronic working switch, a magnetic particle flaw detector starting circuit, and a magnetic particle flaw detector. To make the purpose, technical solution, and effects of this utility model clearer and more explicit, the following describes this utility model in further detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit this utility model.

[0033] In the implementation methods and claims, unless otherwise specified in the text, the terms "a," "an," "the," and "the" may also include plural forms. If the embodiments of this utility model involve descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0034] It should be further understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, "connected" or "coupled" as used herein can include wireless connections or wireless coupling. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.

[0035] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0036] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0037] Magnetic particle testing is an instrument used to inspect surface and near-surface defects in ferrous products. It utilizes the difference in magnetic permeability between the surface and near-surface defects (such as cracks, inclusions, and hairline cracks) and the steel itself, as well as the interaction between the leakage magnetic field at the defect and the magnetic particles. After magnetization, the magnetic field at these material discontinuities is distorted, creating areas of magnetic flux leakage. This generates a leakage magnetic field at the corresponding location on the workpiece surface, attracting magnetic particles and causing them to accumulate at the defect. Under appropriate lighting conditions, the location and shape of the defect become apparent. Observing and interpreting these accumulations of magnetic particles constitutes magnetic particle testing. Magnetic particle testing is one of the five conventional methods of non-destructive testing and a commonly used method for inspecting surface or near-surface defects in ferromagnetic materials. Due to its high detection sensitivity and simple, reliable process, it is widely used.

[0038] After research by the applicant, it is found that during specific operation, the magnetic particle flaw detector has an operation switch. Pressing the operation switch energizes the magnetic particle flaw detector, and releasing it stops the magnetization. The existing operation switches generally adopt mechanical switches, and the working state of the magnetic particle flaw detector is controlled by the connection or disconnection of mechanical contacts. The on-site application working conditions of the magnetic particle flaw detector are very harsh. When performing magnetic particle flaw detection, pressing the operation switch makes the magnetic poles of the magnetic particle flaw detector always magnetic, and then magnetic suspension needs to be sprayed for work. Due to the complex mechanical structure of the flaw detector, it is impossible to achieve complete waterproofing. As the service time increases, the magnetic suspension gradually penetrates into the interior of the flaw detector. When the flaw detector is working, the internal temperature rises, and when it is not working, the temperature drops. With the alternating hot and cold, the moisture convection inside the flaw detector is strong, slowly eroding the mechanical contacts of the operation switch, causing the operation switch to fail. At the same time, since the mechanical switch needs to rely on the contact and separation of mechanical contacts to achieve on and off, as the service time prolongs, problems such as poor contact and mechanical wear may occur in the mechanical contacts, resulting in performance degradation or even failure, and the lifespan of the mechanical switch is relatively low. Therefore, the operation switches of existing magnetic particle flaw detectors have a high failure rate. According to statistics, more than half of the faulty magnetic particle flaw detectors are caused by operation switch failures. There is an urgent need for a long-life switch to replace the existing mechanical operation switch.

[0039] To solve the above technical problems, on the first aspect, the present application provides an electronic operation switch U23, which includes: a switch housing 10, a magnetic field sensor 20, a magnetic structure 30, and a magnetic shielding structure 40; wherein, the switch housing 10 has an accommodation space 11 for accommodating the magnetic shielding structure 40; the magnetic field sensor 20 is arranged on the side wall of the switch housing 10 and is connected to an external circuit through a signal line 21; the magnetic structure 30 is arranged on the side wall and is arranged opposite to the magnetic field sensor 20; the magnetic shielding structure 40 is slidably arranged in the accommodation space 11 inside the switch housing 10 for isolating the magnetic field between the magnetic structure 30 and the magnetic field sensor 20. When the magnetic shielding structure 40 is located between the magnetic field sensor 20 and the magnetic structure 30, the magnetic field sensor 20 outputs a work stop signal to the external circuit; otherwise, the magnetic field sensor 20 outputs a work start signal to the external circuit.

[0040] Specifically, when there is a magnetic field passing through the magnetic field sensor 20, as the magnetic field strength changes, the voltage value of the output signal Vout of the magnetic field sensor 20 varies between 2.5V and 5V, that is, 2.5V < Vout < 5V. For example, when the passing magnetic field exceeds the saturation magnetic field of the magnetic field sensor 20, the output of the magnetic field sensor 20 is 5V; when there is no magnetic field passing through, the output of the magnetic field sensor 20 is 2.5V. Exemplarily, such as Figure 1As shown in Figure a, when the distance between the magnet and the magnetic field sensor 20 is less than the minimum detection distance range of the magnetic field sensor 20, and the magnetic field passing through it exceeds the saturation magnetic field of the magnetic field sensor 20, the output signal Vout of the magnetic field sensor 20 is 5V; Figure 1 As shown in b, when the magnet moves away from the magnetic field sensor 20, the output signal Vout of the magnetic field sensor 20 is 2.5V; Figure 1 As shown in Figure c, when the magnet approaches the magnetic field sensor 20, but there is a magnetic shielding structure 40 between them, the magnetic shielding structure 40 blocks the magnetic field, and the magnetic field sensor 20 does not detect any magnetic field passing through it. Therefore, the output Vout of the magnetic field sensor 20 is 2.5V. To make the output signal of the magnetic field sensor 20 change significantly, the distance between the magnetic field sensor 20 and the magnet can be changed, or a magnetic shielding part 41 can be inserted between them. Using this principle, the function of the magnetic particle flaw detector's start switch can be realized.

[0041] Therefore, in this application, when a magnetic shielding structure 40 is present between the magnetic field sensor 20 and the magnetic structure 30, the output signal of the magnetic field sensor 20 is a work stop signal; when the magnetic shielding structure 40 is not present between the magnetic field sensor 20 and the magnetic structure 30, the output signal of the magnetic field sensor 20 is a work start signal. The switch housing 10 is made of waterproof material to prevent water vapor, magnetic suspension, or other liquids from entering the interior of the switch housing 10. The switch housing 10 can be cylindrical, and it has a receiving space 11 for accommodating the magnetic shielding structure 40, which can slide freely within the receiving space 11. Furthermore, the magnetic field sensor 20 and the magnetic structure 30 are disposed opposite each other on the side wall of the switch housing 10, close to either end of the switch housing 10 in the length direction, so that when the magnetic shielding structure 40 is located at its end and abuts against the switch housing 10, it can naturally be positioned between the magnetic field sensor 20 and the magnetic structure 30. Specifically, when the magnetic shielding structure 40 is located between the magnetic field sensor 20 and the magnetic structure 30, the magnetic shielding structure 40 isolates the magnetic field between the magnetic structure 30 and the magnetic field sensor 20, and the magnetic field sensor 20 outputs a work stop signal to the external circuit. Otherwise, when the magnetic shielding structure 40 is located in other positions within the accommodating space 11, there is a relative magnetic field between the magnetic structure 30 and the magnetic field sensor 20, and the magnetic field sensor 20 outputs a work start signal to the external circuit. This allows the relative position change of the magnetic shielding structure 40 to be converted into a switch signal that can indicate the working state through magnetic induction, thus enabling it to be used as a work switch to control whether electrical components are working. It should be noted that the output signal of the magnetic field sensor 20 when the magnetic shielding structure 40 is located between the magnetic field sensor 20 and the magnetic structure 30 can also be set as a work start signal, and the output signal of the magnetic field sensor 20 when the magnetic shielding structure 40 is located in other positions and the magnetic field sensor 20 and the magnetic structure 30 are directly opposite each other can be set as a work stop signal. This application does not impose any limitations on this.

[0042] Preferably, the magnetic field sensor 20 is model SS495.

[0043] For further information, please refer to [link / reference]. Figure 2The magnetic shielding structure 40 includes a magnetic shielding block and a keycap 42. One end of the magnetic shielding block is fixedly connected to the keycap 42. The keycap 42 is used to drive the magnetic shielding part 41 to slide within the accommodating space 11 inside the switch housing 10. The keycap 42 is used to fix the magnetic shielding block, and at the same time, the keycap 42 plays a transmission role. When the user presses the keycap 42, the keycap 42 drives the magnetic shielding part 41 to move. Exemplarily, the keycap 42 can be directly connected to the magnetic shielding block or indirectly connected to the magnetic shielding block. When the keycap 42 abuts against the switch housing 10, the magnetic shielding part 41 is located between the magnetic field sensor 20 and the magnetic structure 30. At this time, the magnetic field sensor 20 outputs a work stop signal to the external circuit. When a user applies a force to the button cap 42, the button cap 42 applies a force to the magnetic shielding part 41 and drives the magnetic shielding structure 40 to slide towards the end of the accommodating space 11 away from the magnetic field sensor 20 and the magnetic structure 30. The magnetic field sensor 20 outputs an operation start signal to the external circuit.

[0044] Furthermore, the switch housing 10 has a through hole of the first diameter at the corresponding position of the button cap 42, and the button cap 42 extends out of the switch housing 10 through the through hole. The button cap 42 can slide freely in the through hole, so the user can indirectly adjust the position of the magnetic shielding part 41 in the accommodating space 11 by sliding the position of the button cap 42. Preferably, the end of the button cap 42 near the magnetic shielding part 41 has a limiting part 43 with a diameter greater than or equal to the first diameter. When the magnetic shielding part 41 is located between the magnetic field sensor 20 and the magnetic structure 30, the limiting part 43 abuts against the bottom end of the switch housing 10. An annular sealing ring 60 is provided around the through hole. The sealing ring is interference-fitted with the button cap 42 to fill the gap between the button cap 42 and the through hole, further improving the waterproofness of the electronic working switch U23.

[0045] In some preferred embodiments of this application, the electronic working switch U23 further includes a reset structure 50. One end of the reset structure 50 is fixedly connected to the end of the accommodating space 11 away from the through hole, and the other end of the reset structure 50 is fixedly connected to the magnetic shielding structure 40. The reset structure 50 is an elastic reset structure 50, used to drive the magnetic shielding structure 40 to reset between the magnetic field sensor 20 and the magnetic structure 30. Exemplarily, the reset structure 50 can be a spring or other elastic structure. When the magnetic shielding structure 40 slides away from the magnetic field sensor 20, the reset structure 50 is compressed and generates a force opposite to the forward direction of the magnetic shielding structure 40. Thus, when any other external driving force disappears, the magnetic shielding structure 40 will be pushed back to the position between the magnetic field sensor 20 and the magnetic structure 30 by the reset structure 50. The magnetic field sensor 20 outputs a working stop signal to the external circuit, thereby realizing the automatic disconnection of the electronic working switch U23.

[0046] Please see Figure 2 The operation of the electronic working switch U23 is explained using a structural diagram of the switch. Specifically, the magnetic field sensor 20 and the magnet are both encapsulated within the switch housing 10. The magnetic field sensor 20 has a signal line 21 leading out to connect to an external circuit, which receives power and acquires signals through the signal line 21. The button cap 42 is fixedly connected to the magnetic shielding part 41. The reset structure 50 applies a reverse force and abuts the magnetic shielding part 41 against the switch housing 10. The magnetic shielding part 41 is made of a magnetically conductive steel plate, and the reset structure 50 is a spring. The spring presses against the magnetically conductive steel plate. When the button is not pressed down, the button cap 42 is pushed out to its furthest position outside the through hole under the action of the spring. At this time, the magnetically conductive steel plate is inserted between the magnetic field sensor 20 and the magnet, shielding the magnetic field of the magnet. The magnetic field sensor 20 outputs Vout = 2.5V. When the button cap 42 is pressed, the magnetic steel plate is pushed upwards, and the magnetic field of the magnet passes through the magnetic field sensor 20. When the distance between the magnetic field sensor 20 and the magnet is 4-6mm, the output signal Vout of the magnetic field sensor 20 is greater than 3.5V. Therefore, the magnetic field sensor 20 has a voltage change when the button cap 42 is pressed. The change in the output signal of the magnetic field sensor 20 can be used to detect whether the electronic working switch U23 has been pressed. The magnetic field sensor 20 and the magnet are encapsulated in the switch housing 10, making them completely waterproof. A sealing ring is installed between the button and the switch housing 10, making them completely waterproof. The spring is made of stainless steel, and the magnetic shielding part 41 is made of stainless steel magnetic steel plate. Even if the sealing ring is damaged and water enters, the moisture will not affect the spring and the steel plate, so it will not affect the overall electrical performance and lifespan of the switch.

[0047] Secondly, such as Figure 3As shown, this utility model also provides a magnetic particle flaw detector start-up circuit, which includes an electronic working switch U23, a comparison amplifier circuit 200, and a switch status indicator circuit 300 as described above; wherein, the voltage terminal VCC of the electronic working switch U23 is connected to the working voltage +5V, and the electronic working switch U23 is used to generate a switch signal according to the position of the magnetic shielding structure 40, the switch signal being a work stop signal or a work start signal; the position refers to the magnetic shielding structure 40 being located between the magnetic field sensor 20 and the magnetic structure 30 or the magnetic shielding structure 40 not being located between the magnetic field sensor 20 and the magnetic structure 30. Between the magnetic field sensor 20 and the magnetic structure 30; the comparison amplifier circuit 200 is connected to the signal output terminal of the electronic working switch U23, and is used to receive the switch signal in the electronic working switch U23. When the switch signal is a working start signal, the comparison amplifier circuit 200 outputs a high-level signal to the signal output terminal of the electronic working switch U23; when the switch signal is a working stop signal, the comparison amplifier circuit 200 outputs a low-level signal to the signal output terminal of the electronic working switch U23; and converts it into a working start / stop signal to indicate the working status to the working circuit.

[0048] The operating voltage +5V is DC 5V. The signal line 21 of the electronic operating switch U23 includes three terminals: voltage terminal VCC, ground terminal GND, and signal output terminal OUT. The power supply terminal of the electronic operating switch U23 is connected to the operating voltage +5V, the ground terminal GND of the electronic operating switch U23 is grounded, and the signal output terminal OUT of the electronic operating switch U23 is connected to the comparator amplifier circuit 200. The comparator amplifier circuit 200 includes an operational amplifier OP1, a first resistor R1, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a seventh resistor R7. One end of the first resistor R1 is connected to the operating voltage +5V, and the other end is connected to the inverting input of the operational amplifier OP1. One end of the third resistor R3 is connected to the signal output terminal OUT of the electronic operating switch U23, and the other end is connected to the non-inverting input of the operational amplifier OP1. One end of the fourth resistor R4 is connected to the non-inverting input of the operational amplifier OP1, and the other end is connected to the output of the operational amplifier OP1. One end of the fifth resistor R5 is connected to the output of the operational amplifier OP1, and the other end is connected to the switch status indicator circuit 300. One end of the seventh resistor R7 is connected to the common terminal of the first resistor R1 and the inverting input of the operational amplifier OP1, and the other end... The switch status indication circuit 300 includes a first transistor Q1, a second resistor R2, and a sixth resistor R6. The gate of the first transistor Q1 is connected to the comparator amplifier circuit 200 and one end of the sixth resistor R6. The source of the first transistor Q1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is connected to the operating voltage +5V. The drain of the first transistor Q1 is grounded to the other end of the sixth resistor R6. The external signal detection terminal is connected to the common terminal of the second resistor R2 and the source of the first transistor Q1. Preferably, the operational amplifier OP1 is an LM324, and the first transistor Q1 is an NMOS field-effect transistor, specifically a 2N7002.

[0049] Specifically, the magnetic field sensor 20 and operational amplifier OP1 are powered by +5V. When a magnetic field passes through the magnetic field sensor 20, that is... Figure 2When the button cap 42 is pressed, the output signal Vout of the magnetic field sensor 20 is greater than 3.5V. This output signal Vout is connected to pin 5 of operational amplifier OP1 (the positive input of the comparator) through the third resistor R3. The +5V voltage is divided by the first resistor R1 and the seventh resistor R7 to obtain a reference voltage VREF = 3V, which is then connected to pin 6 of operational amplifier OP1 (the negative input of the comparator). Since the input voltage at pin 5 of operational amplifier OP1 is greater than 3.5V, the input voltage at pin 6 is a constant 3V. Therefore, the input voltage at pin 5 of operational amplifier OP1 is greater than the input voltage at pin 6, resulting in a high output voltage (+5V) at pin 7 of operational amplifier OP1. Pin 7 of operational amplifier OP1 is connected to the gate of the first transistor Q1 through the fifth resistor R5, turning on the first transistor Q1, and the external signal detection terminal SW = 0V. When no magnetic field passes through the magnetic field sensor 20, that is... Figure 2 When the button cap 42 is not pressed, the output signal Vout of the magnetic field sensor 20 is 2.5V. This output signal Vout is connected to pin 5 of operational amplifier OP1 through the third resistor R3. Since the input voltage at pin 5 of operational amplifier OP1 is 2.5V and the input voltage at pin 6 is 3V, the input voltage at pin 5 is less than the input voltage at pin 6. Therefore, pin 7 of operational amplifier OP1 outputs a low level (0V). Pin 7 of operational amplifier OP1 is connected to the gate of the first transistor Q1 through the fifth resistor R5, turning off the first transistor Q1. Since the external signal detection terminal SW is connected to +5V through the second resistor R2, the external signal detection terminal SW = 5V. Thus, by detecting whether the external signal detection terminal SW is high (+5V) or low (0V), the state of the start switch (released or pressed) can be determined. The fourth resistor R4 prevents oscillation in the output of operational amplifier OP1. Alternatively, the circuitry other than the magnetic field sensor 20 can be integrated into the switch and potted to achieve complete waterproofing, or this part of the circuitry can be part of other circuitry, which will not be described in detail here.

[0050] In a further embodiment of this invention, the magnetic particle flaw detector's start-up circuit includes a first filter circuit 400 and a second filter circuit 500. The first filter circuit 400 is connected to the voltage terminal VCC of the electronic working switch U23 and the common terminal of the +5V working voltage, and is used for high-frequency filtering of the +5V working voltage. The second filter circuit 500 is connected to the signal output terminal OUT of the electronic working switch U23 and the common terminal of the comparator amplifier circuit 200, and is used for high-frequency filtering of the switching signal output by the magnetic field sensor 20. The first filter circuit 400 includes a first capacitor, and the second filter circuit 500 includes a second capacitor. The first capacitor performs high-frequency filtering of the +5V working voltage provided by the +5V power supply, and the second capacitor performs high-frequency filtering of the output signal Vout of the magnetic field sensor 20.

[0051] Thirdly, this application also provides a magnetic particle flaw detector, which is equipped with the electronic working switch described above. Its specific structure and operation are as described above regarding the electronic working switch, and will not be repeated here.

[0052] In summary, this application provides an electronic working switch, a magnetic particle flaw detector starting circuit, and a magnetic particle flaw detector. The electronic working switch includes: a switch housing, a magnetic field sensor, a magnetic structure, and a magnetic shielding structure. The switch housing has an accommodating space for housing the magnetic shielding structure. The magnetic field sensor is disposed on the side wall of the switch housing and connected to an external circuit via a signal line. The magnetic structure is disposed on the side wall and is positioned opposite to the magnetic field sensor. The magnetic shielding structure is slidably disposed within the accommodating space inside the switch housing to isolate the magnetic field between the magnetic structure and the magnetic field sensor. It has the following characteristics:

[0053] By employing magnetic induction, the positional change of the magnetic shielding structure relative to the magnetic field sensor is converted into a change in the working signal output of the operating switch. This reduces wear and failure issues caused by mechanical contact points, improving measurement accuracy and stability. Furthermore, the non-contact nature of the electronic switch eliminates the need for mechanical contacts, resulting in a long service life and solving the problem of short lifespan of the start-up switch in existing magnetic particle flaw detectors.

[0054] It has a simple structure and small size.

[0055] Completely waterproof, with moving parts and electrical parts completely separated, allowing for complete waterproofing of the electrical components; ideal for use in harsh environments such as magnetic particle testing.

[0056] The circuit incorporates a comparator circuit, allowing for a wide range of magnetic field variations. Even if the magnetic field strength of the magnet decreases, it does not affect the electrical performance, resulting in high reliability and lifespan.

[0057] The reset structure automatically pushes the magnetic shielding structure back to the position between the magnetic field sensor and the magnetic structure, realizing the automatic disconnection of the electronic working switch. This prevents the magnetic particle flaw detector from being damaged due to prolonged high temperature caused by switch failure, thus protecting the magnetic particle flaw detector equipment.

[0058] It should be understood that the application of this utility model is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An electronic operating switch, characterized in that, include: The switch housing, magnetic field sensor, magnetic structure, and magnetic shielding structure; among which, The switch housing has an accommodating space for accommodating the magnetic shielding structure; The magnetic field sensor is mounted on the side wall of the switch housing and is connected to an external circuit via a signal line. The magnetic structure is disposed on the side wall and is positioned opposite to the magnetic field sensor. The magnetic shielding structure is slidably disposed in the accommodating space inside the switch housing to isolate the magnetic field between the magnetic structure and the magnetic field sensor.

2. The electronic operating switch according to claim 1, characterized in that, The magnetic shielding structure includes a magnetic shielding part and a key cap, with one end of the magnetic shielding part fixedly connected to the key cap. The button cap is used to drive the magnetic shielding part to slide within the accommodating space inside the switch housing.

3. The electronic operating switch according to claim 2, characterized in that, The switch housing has a through hole of the first diameter at the corresponding position of the button cap, and the button cap extends out of the switch housing through the through hole.

4. The electronic operating switch according to claim 1, characterized in that, The electronic working switch also includes a reset structure, one end of which is fixedly connected to the end of the accommodating space away from the through hole, and the other end of which is fixedly connected to the magnetic shielding structure; the reset structure is an elastic reset structure, used to drive the magnetic shielding structure to reset between the magnetic field sensor and the magnetic structure.

5. The electronic operating switch according to claim 3, characterized in that, The button cap has a limiting part with a diameter greater than or equal to the first aperture at one end near the magnetic shielding part. When the magnetic shielding part is located between the magnetic field sensor and the magnetic structure, the limiting part abuts against the bottom end of the switch housing.

6. The electronic operating switch according to claim 3, characterized in that, An annular sealing ring is provided around the through hole. The sealing ring is interference-fitted with the button cap and is used to fill the gap between the button cap and the through hole.

7. A starting circuit for a magnetic particle flaw detector, characterized in that, Includes the electronic operating switch, comparator amplifier circuit, and switch status indicator circuit as described in any one of claims 1-6; wherein, The voltage terminal of the electronic working switch is connected to the working voltage. The electronic working switch is used to generate a switching signal according to the position of the magnetic shielding structure. The switching signal is a working stop signal or a working start signal. The position refers to whether the magnetic shielding structure is located between the magnetic field sensor and the magnetic structure or whether the magnetic shielding structure is not located between the magnetic field sensor and the magnetic structure. The comparator amplifier circuit is connected to the signal output terminal of the electronic working switch and is used to receive the switch signal in the electronic working switch. When the switch signal is a working on signal, the comparator amplifier circuit outputs a high-level signal to the signal output terminal of the electronic working switch; when the switch signal is a working off signal, the comparator amplifier circuit outputs a low-level signal to the signal output terminal of the electronic working switch. One end of the switch status indicator circuit is connected to the comparator amplifier circuit, and the other end of the switch status indicator circuit is connected to the working circuit. The switch status indicator circuit is used to receive the high-level signal or the low-level signal and convert it into a working start / stop signal to indicate the working status to the working circuit.

8. The magnetic particle flaw detector start-up circuit according to claim 7, characterized in that, The magnetic particle flaw detector's start-up circuit also includes a first filter circuit and a second filter circuit, wherein... The first filter circuit is connected to the common terminal of the electronic working switch and the working voltage, and the first filter circuit is used to perform high-frequency filtering on the working voltage. The second filter circuit is connected to the common terminal of the signal output terminal of the electronic working switch and the comparison amplifier circuit. The second filter circuit is used to perform high-frequency filtering on the switching signal output by the magnetic field sensor.

9. A magnetic particle flaw detector, characterized in that, The magnetic particle flaw detector is equipped with an electronic working switch as described in any one of claims 1-6.

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