Method for identifying the properties of granular media

Abstract

This invention provides a media classification sensor that can non-contactually determine the particle size and material of granular media used in a shot peening machine. [Solution] The present invention provides a method for detecting the characteristics of granular media, which involves providing a wire coil wound around a media supply tube containing the granular media. The driver is configured to supply alternating current to the wire coil and maintain a constant voltage. A table showing the known characteristics of inductance and impedance for granular media of known materials and specific particle sizes has been prepared in advance. With the granular media held in the wire coil, the driver applies an alternating current, measures the inductance and impedance of the wire coil, and compares the obtained measured values ​​based on the table to determine the material and particle size of the granular media.

Description

[Technical Field]

[0001] The present invention relates to a method for identifying the properties of granular media, and more particularly to a method for easily identifying the properties of granular media used in surface treatment of metal parts, such as shot peening. [Background technology]

[0002] This application claims priority to U.S. Provisional Application No. 63 / 592,623, filed on 24 October 2023, which is incorporated herein by reference in its entirety.

[0003] Shot peening is a useful surface treatment process for metal parts, improving their fatigue life and strength. During the peening process, the parts being treated are exposed to a flow of granular media. To consistently peen parts as expected, the media used for peening must be consistent. This consistency requires maintaining parameters such as the air pressure used to transport the media, a constant media flow rate (measured in pounds per minute), and other factors.

[0004] An important factor that is often overlooked is the media itself. Generally, a specific media is selected depending on the application. When peening is first started with the selected media, it will function as intended if all peening parameters are set to the correct values. However, after repeated use, the media itself does not remain identical, and as the media continues to be used, it degrades to a smaller size, which may make it impossible to achieve the desired peening results.

[0005] The intensity of peening depends on the mass and velocity of the shot (kinetic energy = 1 / 2 × M × V). 2This depends on the media size. Therefore, if the media size deteriorates and becomes smaller due to repeated peening, the peening strength may decrease to an unacceptable level. In addition to media deterioration, there is also the possibility that the operator of the peening machine may mistakenly start peening with inappropriate media. If the media deteriorates over time or inappropriate media is loaded, the operator may experience disappointing and unexpected results throughout the peening process.

[0006] In the current system, the peening process must be stopped to inspect the media. Operators must remove a representative sample of the media from the peening machine and inspect it using a separate device. This inspection is time-consuming and requires additional effort, making frequent media inspection undesirable. Therefore, there is a need for a method that automatically verifies whether the media used for peening is suitable or has deteriorated to the point where it is unusable for the desired peening results. [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention has been made in view of the above-mentioned circumstances, and its objective is to provide a media classification sensor that can determine the particle size and material of granular media used in a shot peening machine without contact. [Means for solving the problem]

[0008] The present invention provides a method for determining the properties of granular media, comprising the step of preparing a wire coil wound around a media supply pipe to accommodate the granular media as it flows through the media supply pipe. A pair of pole pieces are positioned downstream of the wire coil. Various types of granular media are held within the wire coil, each consisting of a known material and having a specific particle size. A driver applies an alternating current to the wire coil, which drives through the wire coil in the presence of the granular media. The impedance and inductance of the wire coil are measured in the presence of each type of granular media within the wire coil. The inductance and impedance values ​​are recorded for each type of granular media present in the wire coil. Different granular media are held within the wire coil, and the impedance and inductance of the wire coil in the presence of the different granular media within the wire coil are compared with the values ​​for each type of granular media to determine the material of the different granular media. [Effects of the Invention]

[0009] According to the present invention, a media classification sensor can be provided that can automatically and non-contactually determine the particle size and material of granular media used in a shot peening machine.

[0010] The media classification sensor of the present invention uses a bobbin and a wire coil placed inside a media supply tube to identify the particle size and material of granular media by detecting changes in inductance and impedance when media is present inside the wire coil.

[0011] This eliminates the need to manually remove the media from the peening machine and inspect it, as was done in the past, and allows for real-time monitoring and determination of the media's condition while the device is running.

[0012] Furthermore, the system of the present invention is equipped with an automatic calibration function and a degradation detection function based on measured values, and the controller can perform control (warning, parameter adjustment, automatic stop, etc.) according to the condition of the media.

[0013] This makes it possible to detect early deterioration and mixing of media, prevent poor quality, and improve the consistency and reliability of the peening process.

[0014] In addition, the sensor according to the present invention can be easily incorporated into the calibration process of the flow rate of granular media, facilitating correction of valve characteristics and variation correction between different valves in the manufacturing process.

[0015] Therefore, the present invention realizes automation of media management, improvement of work efficiency, reduction of maintenance costs, and stabilization of product quality in the peening process.

Brief Description of the Drawings

[0016] [Figure 1] It is a perspective view of a media supply pipe incorporating a sensor, showing the pole piece of a magnetic valve extending therethrough. [Figure 2] It is a cross-sectional view of the media supply pipe and the sensor shown in FIG. 1. [Figure 3] It is a perspective view outside the media supply pipe of the sensor shown in FIGS. 1 and 2. [Figure 4] It is a perspective view showing an opening for guiding the media flowing through the magnetic valve of the sensor in FIG. 3. [Figure 5] It is an overall circuit diagram of a controller connected to the coil in the sensor. [Figure 6] It is a graph showing the relationship between inductance and media particle size. [Figure 7] It is a graph plotting the impedance against the media particle size for different types of media.

Mode for Carrying Out the Invention

[0017] In the following embodiments, the detailed features and advantages of the present invention will be described. The content is sufficient for those skilled in the art to understand the technical content of the present invention and to enable its implementation accordingly. Moreover, based on the disclosure content, claims, and drawings of this specification, those skilled in the art can easily understand the objectives and advantages of the present invention.

[0018] Hereinafter, referring to the related drawings, embodiments of a light source substrate having a branched layout structure of the present invention will be described. For the sake of easy understanding and easy illustration in the drawings, each member in the drawings may be shown with exaggerated or reduced dimensions and ratios.

[0019] FIG. 1 shows an overview of the media classification sensor 10, and FIG. 2 is a cross-sectional view for checking its internal structure. The media classification sensor 10 is part of a media supply system including a magnetic valve 14, and the magnetic valve 14 has a pole piece 16 extending into a media supply pipe 18 that supplies media to a shot peening machine. It is known in the field of shot peening that the pole piece 16 is a conductor that conducts magnetic force at various levels to control the flow of media. The valve 14 can completely stop the flow of media passing through it.

[0020] FIG. 3 is a perspective view of the sensor shown in FIGS. 1 and 2 outside the media supply pipe, and FIG. 4 is a perspective view showing an opening for guiding granular media flowing through the magnetic valve of the sensor in FIG. 3. Immediately above the pole piece 16 is a bobbin 28, around which a conductor coil 34 is wound. The bobbin 28 is inserted into the media supply pipe 18. The bobbin 28 has a circular upper opening 40, and the outer diameter of the bobbin 28 is smaller than the inner diameter of the media supply pipe 18 in which the bobbin 28 is accommodated. The upper opening 40 tapers narrower towards the discharge opening 44. The discharge opening 44 of the bobbin 28 is tapered in the same way as the space between the pole pieces 16. With this structure, the granular media flows smoothly when the valve 14 is operating.

[0021] The granular media flows through the bobbin 28 as the media is supplied through the media supply pipe 18. A valve 14 can stop the flow of the granular media, thereby holding the media in the bobbin 28. A pole piece 16 is located downstream of the bobbin 28 and the wire coil 34, and therefore, when the valve 14 stops the flow of media, the granular media is held in the bobbin 28. The bobbin 28 can be made of electrically non-conductive plastic. A controller 35 acts as a sensor driver and is connected to a wire coil 34 wound around the bobbin 28.

[0022] Figure 5 is an overall circuit diagram showing how the controller 35 that drives the sensor is connected. As shown in Figure 5, the capacitor 36 is connected in parallel with the wire coil 34. The controller 35 controls the wire coil 34 to a specific frequency (f sensor It can be driven at the resonant frequency (f) of the wire coil 34 in the sensor 10. sensor ) is determined by the following formula: Formula 1

[0023] In equation (1) above, the inductance L is in Henrys and the capacitance C is in Farads. The wire coil 34 of the sensor 10 has an initial inductance when there is no media in the bobbin 28. The bobbin 28 is made of a non-conductive material and does not add any inductance beyond what is inherently present in the wire coil 34. The reference frequency (f), inductance (L), and capacitance (C) are based on the empty wire coil 34 when there is no media. The wire coil 34 has a measurable reference impedance in the absence of media.

[0024] The controller 35, which functions as a sensor driver connected to the wire coil 34, maintains a constant voltage, in this case 1.8V. When the controller 35 supplies alternating current to the wire coil 34 in the absence of media according to the frequency formula above, a corresponding reference current is consumed to maintain the constant voltage.

[0025] The inductance of the wire coil 34 is defined by the following equations (2) and (3). Equation 2

[0026] TIFF2026075066000003.tif3274 Here, L is the inductance (Henry) of the wire coil 34, N is the number of turns of the wire coil, and μ is the permeability (absolute value) of the core material. r μ0 is the relative permeability (dimensionless) (μ0 = 1 for air), where μ0 is the permeability of free space, 1.26 × 10⁻⁶. -6 T·m / At, where A is the cross-sectional area (m²) of the wire coil. 2 )=πr 2 , l is the average length (m) of the wire coil.

[0027] In equation (3) above, the only parameter that can change within the sensor's wire coil 34 is the relative permeability of the core (μ). r ) This varies depending on whether or not there is media inside the wire coil 34. Permeability (μ) changes the inductance (L) as shown in equation (2). The permeability of the core depends on the media present inside the wire coil 34 and forming the core. Permeability is greatly influenced by how the media is packed inside the core, and the packing of the media depends on the size of the media particles. To understand how permeability relates to media size, we can consider extreme cases of the core. For example, as an extreme example of a core, a mass of conductive material is expected to exhibit higher permeability than an array of widely spaced and sparsely packed conductive particles. In reality, neither of these extreme cases is likely to occur, but it is useful to consider how this affects permeability and, consequently, inductance.

[0028] Generally, the more magnetically conductive material there is in the conductor coil 34, the stronger the induced magnetic field is established in the core and the more likely inductance is to occur. In the case of the media in the core of the conductor coil 34, the smaller the media particles in the conductor coil 34, the more magnetically conductive material is packed into the conductor coil 34 to form the core. That is, the smaller the media particles, the more magnetically conductive material exists in the conductor coil 34, so the inductance in the conductor coil 34 becomes higher. Small particles minimize the voids in the conductor coil 34 and attract each other relatively densely. This is why granular media with a small particle size maximizes the amount of conductive material in the conductor coil 34. The increase in permeability due to the dense packing of media with a small particle size increases the inductance in the conductor coil 34. This increase in inductance (L) due to the presence of media in the conductor coil 34 changes the frequency (f sensor ) of the conductor coil as described in Equation (1). By measuring this change in frequency, the type of media in the conductor coil 34 can be identified and the average size of the media particles can be determined.

[0029] It is known that when an electrically conductive material is placed in an environment where the magnetic field changes, eddy currents are generated in the electrically conductive material. When the conductor coil surrounds the electrically conductive material in the conductor coil, a magnetic field is applied to the electrically conductive material in the conductor coil. Eddy currents in the electrically conductive material generate a magnetic field in the opposite direction to the magnetic field applied to the electrically conductive material, and the magnetic field caused by these eddy currents repels the change in the magnetic field applied to the material. The eddy currents induced by the conductor coil 34 in the electrically conductive media in the conductor coil 34 repel the magnetic force in the conductor coil 34. This appears as the impedance of the conductor coil 34 when there is an electrically conductive media in the conductor coil 34.

[0030] In this invention, maintaining a constant operating voltage within the wire coil 34 requires that the wire coil 34 consume more current in response to the generation of more eddy currents within the material of the coil 34. The strength of the eddy currents and the resulting impedance of the wire coil 34 are proportional to the type of material. Materials with higher electrical conductivity are more prone to generating eddy currents, and the stronger the eddy currents generated, the greater the impedance the material produces. By measuring the change in current required to maintain a constant voltage, the impedance of the granular media within the core can be identified, and since the required current correlates with the impedance, this can be used to identify the type of material constituting the granular media.

[0031] The wire coil 34 of the sensor 10 can be used to acquire the characteristics of the media within the wire coil 34 in a manner useful to the operator of the peening machine. The characteristics of the granular media that can be determined using the sensor are both particle size and material. The user of the sensor 10 has a characteristic table of inductances for various sizes of media of a specific material. The characteristic table lists the characteristics of various media sizes, allowing the user to refer to the expected inductance based on a specific size for a given media material. It is also effective to store a list of inductances for desired media materials in the controller 35 or a storage device. A list of inductances corresponding to media sizes can be created by holding a known media of a specific size in the coil 34 before the media is actually used.

[0032] Figure 6 is an example of a table listing inductance against media particle size. In Figure 6, the horizontal axis, "Media Volume," represents the average volume of media particles in mm². 3This is represented as follows. The table in Figure 6 shows the decrease in inductance with respect to particle size, that is, the decrease in inductance as the particle size increases. With increasing media particle size, the inductance clearly decreases exponentially. This is due to the packing coefficient of the media. In other words, the larger the media particles, the larger the voids between media particles, which reduces the magnetic permeability and thus the inductance.

[0033] Similar to the inductance table shown in Figure 6, a table of impedances according to media type can also be created. Each media made of a specific material has a different impedance. This is reflected in the graph shown in Figure 7. Since impedance is correlated with the characteristics of the material, the impedance of each material varies depending on the size of the media.

[0034] The tables shown in Figures 6 and 7 can be easily incorporated into the calibration of the valve 14 in the media supply tube 18 using the coil 34. Typically, when calibrating the valve 14 for media flow rate, 10 tests are performed to construct a flow rate profile for a particular valve. During this calibration, new and known media is used to accurately reflect the flow rate of the valve 14. After each of the 10 tests, it is conceivable to hold the media in the media supply tube 18 and coil 34 for a short period. During this short holding period, inductance and impedance values ​​can be obtained for each media. This calibration with new and known media is performed with various new and known media to accurately determine the impedance and inductance values ​​for each coil 34 of each valve 10 manufactured.

[0035] The inductance and impedance values ​​of various new and known media can be stored in memory for comparison with different media later tested in coil 34. The memory may also be located in controller 35. In this way, each valve manufactured is calibrated against media with known characteristics, and the resulting values ​​are associated with each valve. This allows differences between valves due to tolerances to be reflected in separate tables associated with each valve, enabling the media characteristics to be correlated to the tables as accurately as possible.

[0036] During normal use, after each peening cycle, the valve 14 holds the media in the coil 34, and the sensor 10 reads the inductance and impedance of the media in the coil 34. The valve 14 stops periodically to hold the media in the coil 34, so the operator does not need to remove the media from the peening machine.

[0037] The inductance and impedance readings for the granular media within the wire coil 34 can be compared to stored values ​​for various types and sizes of media. For example, Figures 6 and 7 illustrate stored values ​​for a given media type and size. Once the impedance and inductance values ​​for the media within the coil 34 are compared to known values, the sensor 10 can provide information to the user via a graphical interface or other means through the controller 35.

[0038] The valve 14 and sensor 10 may be automated within the peening system to restart peening after each test if the impedance and inductance values ​​for the media are within the guidelines. A predetermined range is given for the inductance and impedance values, and once the media falls outside that range, it is considered unsuitable for further use. In this way, the sensor 10 can determine whether the media has deteriorated to the point where it will not produce the desired peening intensity.

[0039] Furthermore, the controller 35 may provide the user with the opportunity to change peening parameters such as flow rate and airflow driving the media in order to obtain the same intensity even with degraded media. In addition, the controller 35 may recommend changing the peening parameters to obtain the same peening intensity with such degraded media. If the same peening intensity cannot be obtained with degraded media even after changing the parameters, the controller 35 may display a message to that effect.

[0040] If the media sample in the wire coil 34 matches a different type of media than the one intended for use, the controller 35 may issue a warning. A warning for an incorrect media type may automatically change the selected flow rate or prompt the user to make changes to obtain the desired peening intensity. If, over time, the media sample in the wire coil 34 does not meet the impedance or inductance guidelines, the controller 35 may issue a warning indicating that the media is no longer usable. Because the media testing according to the present invention does not require the media to be removed from the peening machine, media degradation over time is more likely to be detected earlier than with other manual inspection methods.

[0041] While each of the embodiments described above is explained in this specification, it should be noted that the invention is not limited to the contents described in the embodiments above, and the embodiments above do not limit the scope of the claims of the present invention. Accordingly, any changes and modifications to the embodiments described herein, or substitution of equivalent structures or processes using the contents of the specification and drawings of the present invention, or direct or indirect application of the above-described technology to other related technical fields, based on the innovative concept of the present invention, are all included within the scope of the claims of the present invention. [Explanation of symbols]

[0042] 10 Media Classification Sensors 14. Magnetic valve (media flow control valve) 16 Pole pieces (magnetic material) 18 Media supply tube 28 bobbins 34 Wire Coil 35 Controller (Sensor Driver) 36 Capacitors 40 Upper opening 44 Discharge opening

Claims

1. The process involves preparing a wire coil wound around a media supply tube for containing granular media, The process involves preparing a driver that passes alternating current through the aforementioned wire coil and maintains the voltage, A step of preparing a table listing known characteristics of inductance and impedance for media made of a predetermined material and of a specific particle size, The steps include holding the granular media within the wire coil, The process of passing the alternating current through the wire coil in the presence of the granular media, A step of measuring the inductance of the granular media in the wire coil, A step of comparing the measured inductance of the granular media in the wire coil with the table and determining the particle size of the granular media in the wire coil, A step of measuring the impedance of the granular media, comparing the measured impedance of the granular media in the wire coil with the table, and determining the material of the granular media in the wire coil. A method for identifying the properties of granular media containing [a specific substance].

2. A method for identifying the characteristics of a granular media according to claim 1, wherein the inductance of the granular media in the wire coil is determined by measuring the change in the oscillation frequency of the alternating current when the granular media is present in the wire coil.

3. A method for identifying the characteristics of a granular media according to claim 2, wherein the impedance of the granular media in the wire coil is determined by measuring the change in current required to maintain a constant voltage with respect to the alternating current in the wire coil.

4. The media supply tube includes a pair of pole pieces for guiding a magnetic field through the media supply tube. The method for identifying the properties of granular media according to claim 3, wherein the pole piece guides a magnetic field at various levels to control the flow of granular media through the wire coil.

5. A method for identifying the properties of granular media according to claim 4, wherein the flow of the granular media is stopped by the pole piece and the granular media is held in the wire coil.

6. A method for identifying the characteristics of a granular media according to claim 1, comprising the step of preparing various granular media of a specific particle size and material properties, and holding each of the granular media in the media supply tube to create a table listing the impedance and inductance of each of the granular media.

7. A method for identifying the characteristics of a granular media according to claim 6, comprising comparing the saved list with the impedance and inductance of the granular media measured after the list was generated.

8. A step of preparing a wire coil wound around a media supply tube that contains granular media so that the granular media flows inside the media supply tube, The steps include providing a pair of pole pieces on the downstream side of the wire coil, A step of holding various granular media of known material and known particle size within the wire coil, The process involves preparing a driver for driving alternating current in the aforementioned wire coil, The process of passing the alternating current through the wire coil while each granular media is present within the wire coil, A step of determining the inductance of the wire coil in the presence of the granular media by measuring the change in the natural frequency of the alternating current while each granular media is present in the wire coil, The steps include: measuring the current flowing through the wire coil in order to maintain a predetermined voltage while the granular media is present in the wire coil, and determining the impedance of the wire coil in the presence of each granular media; A step of recording the inductance and impedance values ​​when each of the granular media is present in the wire coil, The process involves holding different granular media within the wire coil, measuring the shift in the natural frequency of the alternating current when different granular media are present within the wire coil to determine the inductance when the different granular media are held within the wire coil, and measuring the current required to maintain a predetermined voltage when the different granular media are present within the wire coil to determine the impedance of the wire coil. A method for determining the properties of granular media, comprising the step of determining the particle size and material of different granular media by comparing the inductance and impedance values ​​determined when the different granular media are held in the wire coil with the inductance and impedance values ​​of the granular media.

9. A method for identifying the characteristics of a granular media according to claim 8, comprising repeatedly passing different granular media through the conductive coil, comparing the impedance and inductance values ​​of the different granular media with values ​​corresponding to the particle size and material of the different granular media, and determining whether the inductance and impedance values ​​are within a predetermined range for the different granular media.

10. A method for identifying the characteristics of a granular media according to claim 9, wherein the controller adjusts the peening parameters in response to changes in the impedance and inductance values ​​of the different granular media in order to obtain a desired peening intensity.

11. A method for identifying the characteristics of a granular media according to claim 8, wherein a user inputs information about the different granular media, and a controller verifies whether the information corresponds to the characteristics of the different granular media based on the impedance and inductance values ​​of the different granular media.

12. A step of preparing a wire coil wound around the media supply pipe in order to contain the granular media flowing inside the media supply pipe, The steps include providing a pair of pole pieces on the downstream side of the wire coil, A step of holding various granular media having known materials and known particle sizes inside the wire coil, The process involves preparing a driver for driving alternating current in the aforementioned wire coil, The process of passing the alternating current through the wire coil while each granular media is present within the wire coil, A step of determining the inductance of the wire coil in the presence of each of the granular media, A step of determining the impedance of the wire coil in the presence of each granular media, A step of recording the inductance and impedance values ​​when each of the granular media is present in the wire coil, The process involves holding different granular media within the wire coil, measuring the shift in the natural frequency of the alternating current when the different granular media are present within the wire coil to determine the inductance when the different granular media are held within the wire coil, and measuring the current required to maintain a predetermined voltage when the different granular media are present within the wire coil to determine the impedance of the wire coil. A method for identifying the characteristics of granular media, comprising the step of determining the particle size and material of each of the different granular media by comparing the inductance and impedance values ​​determined when the different granular media are held in the wire coil with the inductance and impedance values ​​of each of the granular media.

13. A method for identifying the characteristics of granular media according to claim 12, comprising repeatedly flowing different granular media through the conductive coil, comparing the impedance and inductance values ​​of the different granular media with values ​​corresponding to the particle size and material of the different granular media, and determining whether the inductance and impedance values ​​fall within a predetermined range for the different granular media.

14. A method for identifying the characteristics of a granular media according to claim 13, wherein the controller adjusts the peening parameters in response to changes in the impedance and inductance values ​​of the different granular media in order to obtain a desired peening intensity.

15. A method for identifying the characteristics of a granular medium according to claim 12, wherein a user inputs information about the different granular medium, and a controller verifies whether the information corresponds to the characteristics of the different granular medium based on the impedance and inductance values ​​of the different granular medium.

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