Micro-electric field chip, granular material physical property characterization device and method

Abstract

The invention discloses a micro electric field chip and a granular material physical property characterization device and method, and relates to the technical field of material characterization, the micro electric field chip comprises a bottom plate, the upper surface of which is provided with a pretreatment zone and a photoelectric detection zone; the cover plate is fixedly and hermetically arranged on the bottom plate, a sample inlet communicated with the pretreatment area is formed in the cover plate, and particle materials to be detected can be conveyed into the pretreatment area and enter the photoelectric detection area after being orderly arranged in the pretreatment area; the detection device is located in the photoelectric detection area and can detect the boundary dimension and electrical parameters of the to-be-detected granular material; according to the micro electric field chip and the granular material physical property characterization device and method provided by the invention, comprehensive characterization of the boundary dimension and electrical parameters of the granular material can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of material characterization, and in particular to a micro-electric field chip, a device and a method for characterizing the physical properties of granular materials. Background Art

[0002] Granular materials, due to their large surface area, high reactivity, and excellent dispersibility, play an irreplaceable role in precision manufacturing applications such as semiconductor packaging and aerospace components. In the semiconductor industry, the uniformity of the particle size distribution and electrical properties directly impact the consistency and reliability of the packaging process. In the aerospace field, the manufacture of lightweight structural parts often relies on laser melting technology, which requires highly uniform granular materials for efficient implementation. Therefore, accurate characterization of granular material properties, such as external dimensions and electrical parameters, is crucial.

[0003] In traditional characterization techniques, the external shape characterization of granular materials usually adopts methods such as laser particle size analysis and dynamic light scattering, while the electrical parameter characterization of particles usually adopts methods such as capacitance method, frequency domain reflectometry, and AC impedance method. None of the above methods can achieve the simultaneous acquisition of the external dimensions and electrical parameters of the particles, resulting in low characterization efficiency. In addition, in traditional methods for characterizing the electrical parameters of granular materials, it is usually necessary to press the granular materials into blocks before conducting overall inspection, which not only increases the complexity of sample processing, but also introduces additional measurement errors due to deformation and arrangement differences during the pressing process. In terms of the comprehensive characterization of the external dimensions and electrical parameters of granular materials, the defects of low efficiency and large errors in traditional technologies have seriously restricted the development of related industries. Therefore, there is an urgent need to develop a technical solution that can achieve comprehensive characterization of the external dimensions and electrical parameters of granular materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a micro-electric field chip, a device and method for characterizing the physical properties of granular materials to solve the problems existing in the above-mentioned prior art and to achieve comprehensive characterization of the external dimensions and electrical parameters of granular materials.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a micro-electric field chip, comprising:

[0007] A bottom plate, the upper surface of which is provided with a pre-processing area and a photoelectric detection area;

[0008] a cover plate, fixedly and sealedly disposed on the bottom plate, and provided with a sample inlet connected to the pre-treatment area, capable of conveying the particulate material to be tested into the pre-treatment area, and then entering the photoelectric detection area after being orderly arranged in the pre-treatment area;

[0009] The detection device is located in the photoelectric detection area and can detect the external dimensions and electrical parameters of the particle material to be detected.

[0010] Preferably, the photoelectric detection area includes a detection groove opened on the bottom plate, and the pre-processing area includes a pre-processing channel opened on the bottom plate, and the end of the pre-processing channel is connected to the detection groove; transparent windows are provided on both the cover plate and the bottom plate, the transparent window of the cover plate is located at the top of the detection groove, and the transparent window of the bottom plate is located at the bottom of the detection groove.

[0011] Preferably, the detection device includes a camera, a picoammeter and microelectrodes symmetrically arranged on both sides of the detection slot, the microelectrodes can move horizontally away from or close to the detection slot; the microelectrodes can apply a DC voltage to the detection slot; the particle material to be tested generates a pulse current signal when passing through the detection slot, the picoammeter is used to collect the pulse current signal, and the camera is arranged outside the transparent window to collect images of the particle material to be tested passing through the detection slot.

[0012] Preferably, the base plate is provided with a first groove at a position below the photoelectric detection area, and the cover plate is provided with a second groove at a position above the photoelectric detection area. Transparent plates are sealed in the first and second grooves, and the transparent plates form the transparent window.

[0013] Preferably, the pre-treatment zone is provided with a spiral channel, the outermost end of the spiral channel is connected to the detection tank through the pre-treatment channel, and the sample inlet is connected to the innermost end of the spiral channel.

[0014] Preferably, the two sides of the pre-treatment channel are connected with symmetrically arranged sheath flow air channels, and the cover plate is provided with two symmetrically arranged sheath flow gas inlets, one end of the sheath flow gas inlet is connected to an external gas source, and the other end is connected to the sheath flow air channel at the corresponding position, the sheath flow gas inlet is connected to the end of the sheath flow air channel away from the photoelectric detection area, and the end of the sheath flow air channel close to the photoelectric detection area is connected to the pre-treatment channel.

[0015] Preferably, electrode grooves are symmetrically provided on both sides of the detection groove, a slider is slidably provided in the electrode groove, the microelectrode is fixedly inserted into the slider on the corresponding side, and the end of the slider away from the detection groove is connected to the bottom plate through an adjustment device, and the adjustment device can drive the slider to slide along the electrode groove to the set position.

[0016] The present invention also provides a device for characterizing the physical properties of granular materials, comprising an air compression pump, an aerosol generator, and a drying tube connected in sequence, wherein the micro-electric field chip as described above is provided at the end of the drying tube, and the air outlet end of the drying tube is connected to the sample inlet of the micro-electric field chip through a pipeline; the end of the photoelectric detection area is connected to a gas storage tank through a pipeline; a camera is provided on the outside of the transparent window, and a picoammeter is provided in the photoelectric detection area, the picoammeter and the camera are both electrically connected to a controller, and the picoammeter and the camera are both connected to computer signals.

[0017] The present invention also provides a method for characterizing the physical properties of granular materials based on the granular material physical properties characterization device, comprising the following steps:

[0018] Using an aerosol generator to form a particle aerosol from the particle material to be tested;

[0019] The particle aerosol is passed into the micro-electric field chip so that it enters the photoelectric detection area in an orderly manner;

[0020] When the particle aerosol passes through the photoelectric detection area, the corresponding current signal and optical image are collected;

[0021] A computer receives the current signal and optical image and analyzes and calculates the physical properties of the particles. Microelectrodes are located on both sides of the photoelectric detection zone. A DC voltage of 1 to 2000V is applied to the positive electrode. When particles pass through the detection zone, a pulsed current signal is generated. This current signal is collected using a picoammeter with a measurement range of 10pA to 1A and an acquisition period of 0.1ms to 1000ms. The current signal is also transmitted as a control signal to the controller, driving the camera to synchronously capture the optical image of the particles. The maximum frame rate of the camera is controlled at 100 to 10,000 fps. The physical properties of the particles analyzed and calculated primarily include external parameters such as size distribution, coefficient of variation, and average roundness, as well as electrical parameters such as conductivity and dielectric constant.

[0022] Preferably, the aerosol generator generates the particulate aerosol based on the principle of dry powder dispersion or spray drying, and the particle concentration of the particulate aerosol is 0.01 to 0.5 g / mL; the flow rate of the particulate aerosol is 0.1 mL / min to 10 mL / min.

[0023] Compared with the prior art, the present invention has achieved the following technical effects:

[0024] The present invention arranges aerosol particles in an orderly manner through the pre-treatment area of ​​a micro-electric field chip, uses microfluidics to precisely control the flow field, combines the camera of the optical imaging system to capture the aerosol particle morphology characteristics in the photoelectric detection area in real time, and simultaneously uses a picoampere ammeter to collect the current response signal of the aerosol particles, realizing the direct characterization of discrete particle characteristics in coordination with the three fields of "flow, light, and electricity", and integrating the material's external dimensions and electrical parameter characterization into an independent computer, which greatly reduces the additional errors in traditional particle material characterization technology and greatly improves the characterization efficiency.

[0025] The present invention uses an aerosol generator to fully disperse the particulate material sample to form a particulate aerosol, which is then passed into a micro-electric field chip. The particles enter the photoelectric detection area in an orderly manner under the action of the chip pre-treatment area. Through photoelectric signal fusion sensing, the pulse current signal and the particle optical image are combined for analysis and calculation to achieve the characterization of the particulate material. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 is a schematic diagram of the arrangement of a granular material characterization apparatus according to one or some embodiments of the present invention;

[0028] Figure 2 is an overall schematic diagram of a micro-electric field chip according to one or some embodiments of the present invention;

[0029] Figure 3 Schematic diagram of the cover structure of the micro-electric field chip according to one or some embodiments of the present invention;

[0030] Figure 4 is a schematic side view of a cover structure of a micro-electric field chip according to one or some embodiments of the present invention;

[0031] Figure 5 Schematic diagram of the bottom plate structure of the micro-electric field chip according to one or some embodiments of the present invention;

[0032] Figure 6 is a schematic side view of the bottom plate structure of the micro-electric field chip according to one or some embodiments of the present invention;

[0033] Figure 7 It is a schematic diagram of the slider structure of the micro-electric field chip according to one or some embodiments of the present invention;

[0034] Figure 8is a schematic side view of a slider structure of a micro-electric field chip according to one or some embodiments of the present invention;

[0035] Figure 9 It is a schematic diagram of the working mechanism of the micro-electric field chip in the present invention.

[0036] In the figure: 1. air compression pump, 2. aerosol generator, 3. drying tube, 4. micro-electric field chip, 5. gas storage tank, 6. power supply, 7. picoammeter, 8. controller, 9. camera, 10. computer, 41. first transparent plate, 42. cover plate, 43. bottom plate, 44. slider, 45. adjustment device, 46. microelectrode, 47. second transparent plate, 4-1. sample inlet, 4-2. sheath gas inlet, 4-3. pretreatment area, 4-4. photoelectric detection area. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] The purpose of the present invention is to provide a micro-electric field chip, a device and method for characterizing the physical properties of granular materials to solve the problems existing in the above-mentioned prior art and to achieve comprehensive characterization of the external dimensions and electrical parameters of granular materials.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] In traditional characterization techniques, the appearance of granular materials is usually characterized by laser particle size analysis, dynamic light scattering and other methods, while the electrical parameters of particles are usually characterized by capacitance method, frequency domain reflectometry, AC impedance method and other methods. None of the above methods can achieve the simultaneous acquisition of the particle size and electrical parameters. In order to solve this problem, the first purpose of the present invention is to provide a micro electric field chip, with reference to Figures 1 to 9 As shown, it includes a base plate 43, the upper surface of which is provided with a pre-treatment area 4-3 and a photoelectric detection area 4-4; a cover plate 42 is fixedly and sealedly arranged on the base plate 43, for sealing the pre-treatment area 4-3 and the photoelectric detection area 4-4 of the base plate 43, and a sample inlet 4-1 connected to the pre-treatment area 4-3 is provided on the cover plate 42, which can transport the particle material to be tested into the pre-treatment area 4-3, and enter the photoelectric detection area 4-4 after being arranged in an orderly manner in the pre-treatment area 4-3; the detection device is located in the photoelectric detection area 4-4, and can detect the external dimensions and electrical parameters of the particle material to be tested.

[0041] In one embodiment, the photoelectric detection area 4-4 includes a detection tank provided on the bottom plate 43, and the pre-treatment area 4-3 includes a pre-treatment channel provided on the bottom plate 43, the end of the pre-treatment channel being connected to the detection tank. Transparent windows are provided on both the cover plate 42 and the bottom plate 43, with the transparent window of the cover plate 42 being located at the top of the detection tank and the transparent window of the bottom plate 43 being located at the bottom of the detection tank. The detection device of this embodiment includes a camera 9, a picoammeter 7, and microelectrodes 46 symmetrically arranged on both sides of the detection tank, the microelectrodes 46 being capable of horizontally moving away from or toward the detection tank; the microelectrodes 46 being capable of applying a DC voltage to the detection tank; a pulse current signal is generated when the particle material to be tested passes through the detection tank, the picoammeter 7 being used to collect the pulse current signal, and the camera 9 being arranged outside the transparent window to collect an image of the particle material to be tested passing through the detection tank. The present invention arranges aerosol particles in an orderly manner through the pre-treatment area 4-3 of the micro-electric field chip 4, uses microfluidics to precisely control the flow field, and combines the camera 9 of the optical imaging system to capture the aerosol particle morphology characteristics of the photoelectric detection area 4-4 in real time. The picoammeter 7 is simultaneously used to collect the current response signal of the aerosol particles, thereby realizing the direct characterization of discrete particle characteristics in coordination with the three fields of "flow, light, and electricity", and integrating the material's external dimensions and electrical parameter characterization into an independent computer 10, which greatly reduces the additional errors in traditional particle material characterization technology and greatly improves the characterization efficiency.

[0042] In this embodiment, the cover plate 42 and base plate 43 are made of polymer materials such as PMMA, PVDF, PDMS, and PCB. Microelectrodes 46 are made of non-metallic conductive materials such as carbon fiber and graphite, or metal materials such as silver, copper, and tungsten, with a diameter of 5 to 500 μm. The cover plate 42 and base plate 43 are manufactured using methods such as laser cutting, mechanical engraving, or 3D printing.

[0043] The specific form of the transparent window is not limited. The corresponding positions of the cover plate 42 and the bottom plate 43 can be directly designed as transparent structures to form a transparent window. In a preferred embodiment, the bottom plate 43 is provided with a first groove at a position located below the photoelectric detection area 4-4, and the cover plate 42 is provided with a second groove at a position located above the photoelectric detection area 4-4. The first transparent plate 41 is sealed in the first groove, and the second transparent plate 47 is sealed in the second groove. The first transparent plate 41 and the second transparent plate 47 form a transparent window. The first transparent plate 41 and the second transparent plate 47 can be made of, but not limited to, quartz glass, organic glass, PDMS, or other materials.

[0044] The pre-treatment area 4-3 is provided with a spiral channel. The outermost end of the spiral channel is connected to the detection tank through the pre-treatment channel. The sample inlet 4-1 is connected to the innermost end of the spiral channel, that is, the sample inlet 4-1 is connected to the end of the spiral channel located at the center of the spiral. The pre-treatment channel is connected to symmetrically arranged sheath flow airways on both sides. The cover plate 42 is provided with two symmetrically arranged sheath flow gas inlets 4-2. One end of the sheath flow gas inlet 4-2 is connected to an external gas source, and the other end is connected to the sheath flow airway at the corresponding position. The sheath flow gas inlet 4-2 is connected to the end of the sheath flow airway away from the photoelectric detection area 4-4, and the end of the sheath flow airway close to the photoelectric detection area 4-4 is connected to the pre-treatment channel. Through the structural design of the spiral channel or the application of a physical field or the design of a sheath flow airway, the particles in the aerosol are arranged in an orderly manner and enter the photoelectric detection area 4-4 in an orderly manner.

[0045] In one embodiment, electrode grooves are symmetrically provided on both sides of the detection slot, and a slider 44 is slidably provided in the electrode groove. The material of the slider 44 is a polymer material such as PMMA, PVDF, PDMS, PCB, etc.; the microelectrode 46 is fixedly provided in the slider 44 on the corresponding side, and the slider 44 is connected to the bottom plate 43 through an adjustment device 45 at the end away from the detection slot. The adjustment device 45 can drive the slider 44 to slide along the electrode groove to a set position. The slider 44 is manufactured by 3D printing or molding. A through hole is provided in the center of the slider 44 for placing the microelectrode 46, and an adjustment device 45 is embedded on the outside. There is no restriction on the adjustment device 45. A screw nut pair can be used to drive the slider 44, or a micro cylinder can be used as the adjustment device 45 to drive the slider 44. The driving principle is all existing technology and will not be described in detail.

[0046] In one embodiment, the cover plate 42 is rectangular with dimensions L1*W1*H1, where H1 = 0.2-3 mm. The base plate 43 is rectangular with dimensions L1*W1*H2, where H2 = 0.5-5 mm. The cross-sectional dimensions of the pre-processing channel on the base plate 43 are W2*H3, where W2 = 0.05-1 mm. The recess for accommodating the transparent plate measures L2*W3*H4. The slider 44 has a length of L3, a width of W4, and a height of H3. Here, H3+H4=H2, W4<L2, L3<(W1-W2) / 2, W2 / H3=0.5-5, and L2 / W3=0.8-2. The microelectrode 46 is fixed to the slider 44 and, in conjunction with the slide groove, achieves modular installation. The appropriate electrode spacing S can be adjusted according to the particle size to be measured, with S controlled to be between 0.01 mm and 5 mm.

[0047] The second object of the present invention is to provide a device for characterizing the physical properties of granular materials, Figure 1As shown, it includes an air compression pump 1, an aerosol generator 2, and a drying tube 3 connected in sequence. The micro-electric field chip 4 as described above is provided at the end of the drying tube 3. The air outlet end of the drying tube 3 is connected to the sample inlet 4-1 of the micro-electric field chip 4 through a pipeline. The end of the photoelectric detection area 4-4 is connected to a gas storage tank 5 through a pipeline. A camera 9 is provided on the outside of the transparent window, and the photoelectric detection area 4-4 is provided with a picoammeter 7. The picoammeter 7 and the camera 9 are both electrically connected to a controller 8, which is a PLC controller. The picoammeter 7 and the camera 9 are both signal-connected to a computer 10. The present invention utilizes the aerosol generator 2 to fully disperse the particulate material sample to form a particulate aerosol. The particulate aerosol is passed into the micro-electric field chip 4. The particles enter the photoelectric detection area 4-4 in an orderly manner under the action of the chip pre-treatment area 4-3. The photoelectric signal fusion sensing is combined with the pulse current signal and the particle optical image for analysis and calculation to achieve the characterization of the particulate material.

[0048] The third object of the present invention is to provide a method for characterizing the physical properties of granular materials based on a granular material physical properties characterization device, referring to Figure 1 As shown, Figure 1 The solid arrows in the figure represent the material flow path of the particles to be tested, the dotted arrows represent the transmission path of the detection data, and the dotted lines represent the flow path of the current. The method includes the following steps:

[0049] Aerosol generator 2 is used to generate a particle aerosol from the particulate material to be tested. Aerosol generator 2 processes the particulate material sample, transforming the test material from a collection of solid particles into an aerosol containing evenly dispersed particles, thereby enabling direct characterization of discrete particles. To avoid damage to the particulate material during aerosol generation, a dry powder dispersion method or spray drying method should be used to generate the aerosol. Furthermore, both low and high particle concentrations will affect the test results; the particle concentration should be controlled between 0.01 and 0.5 g / mL.

[0050] The particle aerosol is introduced into the micro-electric field chip 4 so that it enters the photoelectric detection area 4-4 in an orderly manner; the particle aerosol can be introduced into the micro-electric field chip 4 using equipment such as a pressure pump or a micro-flow pump. Due to the small cross-sectional area of ​​the channel inside the chip, the particle aerosol should be introduced at a relatively low flow rate, and the flow rate of the particle aerosol is 0.1mL / min to 10mL / min; the pre-treatment area 4-3 of the micro-electric field chip 4 can arrange the particles in the aerosol in an orderly manner through structural design or external physical field, and enter the photoelectric detection area 4-4 in an orderly manner. Structural design includes but is not limited to the application of a spiral channel or sheath flow structure; external physical field includes but is not limited to adding electrodes on both sides of the flow channel, applying a higher voltage, and using the ion wind effect to control the movement of particles;

[0051] When the particle aerosol passes through the photoelectric detection zone 4-4, the corresponding current signal and optical image are collected. A DC power supply 6 applies a certain voltage to the microelectrode 46, causing a corona discharge in the detection area, generating a weak current. As the particles pass through the detection zone, the circuit resistance changes and a pulse current signal is generated. During the discharge process, if the voltage is too low, corona discharge will not occur, while if the voltage is too high, it will break down the gas in the flow channel and cause a short circuit. Therefore, the voltage should be controlled between 1 and 2000V. The corona discharge current is relatively weak, and the ammeter detection range should be between 10pA and 1A. In addition, due to the small flow channel size and the rapid gas flow rate, the frequency of particles passing through the detection zone is high, requiring the ammeter acquisition cycle to be sufficiently short, controlled between 0.1ms and 1000ms. Based on the pulse current signal collected by the ammeter, the controller 8 drives the camera 9 to achieve synchronous acquisition of the photoelectric signal. Due to the high frequency of particles passing through the detection zone, the maximum frame rate of the image captured by the camera 9 must be sufficiently high, controlled between 100 and 1000fps.

[0052] Computer 10 receives the current signal and optical image, analyzes and calculates the physical properties of the particles; computer 10 extracts the area and perimeter of the discrete particles based on the optical image, and then calculates the external dimension parameters such as diameter and roundness. Combined with the pulse current amplitude, it can further calculate electrical parameters such as conductivity and dielectric constant, and characterize the physical properties of the granular material through statistical analysis.

[0053] Example 1

[0054] Titanium dioxide particles are characterized according to the method and apparatus of the present invention, and the test results are output.

[0055] The method includes:

[0056] An aerosol generator 2 is used to form titanium dioxide particles into a particulate aerosol. The particulate aerosol is passed into a micro-electric field chip 4 so that it enters a photoelectric detection area 4-4 in an orderly manner. As the particulate aerosol passes through the photoelectric detection area 4-4, a corresponding current signal and an optical image are collected. A computer 10 receives the current signal and the optical image and analyzes and calculates the average particle diameter, D50, average roundness, and dielectric constant.

[0057] The device includes:

[0058] A microelectrode 46 for applying the electric field is fixed to the center of a slider 44, which is mounted on a slot in a base plate 43 and can be moved by a lateral adjustment mechanism 45. A cover plate 42, used for packaging, is covered with a transparent plate and connected to the gas delivery device via the sample inlet 4-1 and the sheath gas inlet, respectively. A base plate 43 provides a gas channel and detection space. These cover plate 42 and base plate 43 are sealed by heat-compression bonding. The entire device is connected to the aerosol generator 2 via the sample inlet 4-1 and to the gas storage tank 5 via the output port.

[0059] Process conditions:

[0060] The concentration of the particulate aerosol is controlled at 0.3 g / ml, and the aerosol flow rate is controlled at 0.5 mL / min; the voltage applied to the microelectrode 46 is 1000 V; the size of the cover plate 42 is 75 mm*35 mm*2 mm; the size of the bottom plate 43 is 75 mm*35 mm*3 mm, the cross-sectional size of the pretreatment channel thereon is 0.5 mm*1 mm, and the size of the groove for placing the transparent plate is 3 mm*3 mm; the length of the slider 44 is 10 mm and the width is 2 mm; the material of the microelectrode 46 is carbon fiber, the diameter is 0.005 mm, and the electrode spacing is controlled to be 40 μm.

[0061] Experimental results:

[0062] After 30 seconds of aerosol injection, all test parameters were essentially stable. The final output showed an average particle diameter of 11.12 μm and a D50 of 10.17 μm. D50, also known as the "median diameter," refers to the value at which exactly 50% of the particles in the cumulative distribution of particle sizes are smaller than this value, while the remaining 50% are larger. It reflects the average particle size and is a key indicator of powder size distribution. The average roundness was 0.83, and the dielectric constant was 5.92.

[0063] Example 2

[0064] The silicon carbide particles were characterized and the test results were output according to the method and apparatus in Example 1, except that the voltage applied to the microelectrode 46 was adjusted to 600 V, the electrode spacing was adjusted to 50 μm, and the analysis and calculation parameters were changed to average diameter, D50, average roundness, and conductivity.

[0065] Experimental results:

[0066] After 40 seconds of aerosol introduction, all test items were basically stable. In the final output results, the average diameter of the sample particles was 25.06μm, D50 was 24.37μm, the average roundness was 0.78, and the conductivity was 46.13S / cm.

[0067] Example 3

[0068] The silicon dioxide particles were characterized and the test results were output according to the method and apparatus in Example 1, with the following differences: the voltage applied to the microelectrode 46 was adjusted to 1500 V, and the electrode spacing was adjusted to 20 μm.

[0069] Experimental results:

[0070] After 20 seconds of aerosol introduction, all test items were basically stable. In the final output results, the average diameter of the sample particles was 9.32μm, D50 was 9.44μm, the average roundness was 0.67, and the dielectric constant was 4.07.

[0071] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A micro-electric field chip, characterized in that: include: A bottom plate, the upper surface of which is provided with a pre-processing area and a photoelectric detection area; a cover plate, fixedly and sealedly disposed on the bottom plate, and provided with a sample inlet connected to the pre-treatment area, capable of conveying the particulate material to be tested into the pre-treatment area, and then entering the photoelectric detection area after being orderly arranged in the pre-treatment area; The detection device is located in the photoelectric detection area and can detect the external dimensions and electrical parameters of the particle material to be detected.

2. The micro-electric field chip according to claim 1, characterized in that: The photoelectric detection area includes a detection groove opened on the bottom plate, and the pre-processing area includes a pre-processing channel opened on the bottom plate, and the end of the pre-processing channel is connected to the detection groove; transparent windows are provided on both the cover plate and the bottom plate, the transparent window of the cover plate is located at the top of the detection groove, and the transparent window of the bottom plate is located at the bottom of the detection groove.

3. The micro-electric field chip according to claim 2, characterized in that: The detection device includes a camera, a picoammeter and microelectrodes symmetrically arranged on both sides of the detection slot, the microelectrodes can move horizontally away from or close to the detection slot; the microelectrodes can apply a DC voltage to the detection slot; the particle material to be tested generates a pulse current signal when passing through the detection slot, the picoammeter is used to collect the pulse current signal, and the camera is arranged outside the transparent window to collect images of the particle material to be tested passing through the detection slot.

4. The micro-electric field chip according to claim 2, characterized in that: The bottom plate is provided with a first groove at the lower part of the photoelectric detection area, and the cover plate is provided with a second groove at the upper part of the photoelectric detection area. Transparent plates are sealed in the first and second grooves, and the transparent plates form the transparent window.

5. The micro-electric field chip according to claim 2, characterized in that: The pre-treatment area is provided with a spiral channel, the outermost end of the spiral channel is connected to the detection tank through the pre-treatment channel, and the sample inlet is connected to the innermost end of the spiral channel.

6. The micro-electric field chip according to claim 2, characterized in that: The two sides of the pre-treatment channel are connected with symmetrically arranged sheath flow air channels, and the cover plate is provided with two symmetrically arranged sheath flow gas inlets, one end of the sheath flow gas inlet is connected to an external gas source, and the other end is connected to the sheath flow air channel at the corresponding position, the sheath flow gas inlet is connected to the end of the sheath flow air channel away from the photoelectric detection area, and the end of the sheath flow air channel close to the photoelectric detection area is connected to the pre-treatment channel.

7. The micro-electric field chip according to claim 3, characterized in that: Electrode grooves are symmetrically provided on both sides of the detection groove, and sliders are slidably provided in the electrode grooves. The microelectrodes are fixedly inserted into the sliders on the corresponding sides. The end of the slider away from the detection groove is connected to the bottom plate through an adjustment device, and the adjustment device can drive the slider to slide along the electrode groove to the set position.

8. A device for characterizing the physical properties of granular materials, characterized by: It includes an air compression pump, an aerosol generator, and a drying tube connected in sequence, the end of the drying tube is provided with a micro-electric field chip as described in any one of claims 1 to 7, the air outlet end of the drying tube is connected to the sample inlet of the micro-electric field chip through a pipeline; the end of the photoelectric detection area is connected to a gas storage tank through a pipeline; a camera is provided on the outside of the transparent window, and a picoammeter is provided in the photoelectric detection area, the picoammeter and the camera are both electrically connected to a controller, and the picoammeter and the camera are both connected to computer signals.

9. A method for characterizing the physical properties of granular materials based on the granular material physical properties characterization device according to claim 8, characterized in that: The steps include: Using an aerosol generator to form a particle aerosol from the particle material to be tested; The particle aerosol is passed into the micro-electric field chip so that it enters the photoelectric detection area in an orderly manner; When the particle aerosol passes through the photoelectric detection area, the corresponding current signal and optical image are collected; The computer receives the current signal and optical image, and analyzes and calculates the physical properties of the particles.

10. The method for characterizing the physical properties of granular materials according to claim 9, characterized in that: The aerosol generator generates particulate aerosol based on the principle of dry powder dispersion method or spray drying method. The particle concentration of the particulate aerosol is 0.01~0.5g / mL; the flow rate of the particulate aerosol is 0.1mL / min~10mL / min.

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