Brush discharge simulation experiment device based on rotation mechanism

Abstract

The invention relates to a brush-shaped discharge simulation experiment device based on a rotation mechanism. The brush-shaped discharge simulation experiment device comprises a rotation supporting system. And a feeding system, a corona electricity spraying system and a discharging system are uniformly distributed above the circumferential direction of the rotary supporting system. The rotary supporting system comprises a rotary table driven by a stepping motor, a material bearing module rotating along with the rotary table is arranged on the rotary table, and the material bearing module comprises a metal back plate, a dielectric plate and a flame-retardant insulating plate which are sequentially arranged from bottom to top; the metal back plate is fixedly connected with the turntable and is grounded through a cable, and a circular sample groove is formed in the flame-retardant insulating plate. According to the invention, multi-degree-of-freedom motion cooperative control can be realized, brush-shaped discharge phenomena under different working conditions can be accurately reproduced, and a standardized experimental platform is provided for performance evaluation and discharge mechanism research of electrostatic protection materials.

Description

Technical Field

[0001] The present invention relates to a brush discharge simulation experimental device based on a rotation mechanism. Background Art

[0002] In typical industrial scenarios such as powder pneumatic conveying, polymer material injection molding, and flexible bulk container handling, the electrostatic charge accumulation phenomenon caused by the coupling of highly insulating materials such as polypropylene and polyethylene with dynamic contact-separation processes has become a core risk source in modern industrial safety production systems. When a charge density gradient is generated on the surface of an insulating medium due to triboelectric charging, turbulent fluid shear, or external electrostatic field polarization, its surface potential can rapidly climb to the kilovolt level. At this time, a local strong electric field (typical field strength > 3×10 6 V / m) will be formed between the charged surface and the adjacent grounded conductor, inducing a brush discharge phenomenon with transient characteristics.

[0003] Regarding the physical mechanism and prevention and control strategies of brush discharge, the academic community has carried out systematic research. Existing literature has reported the generation law of the special mode of surface discharge - Lichtenberg figures under high charge density (> 250 μC / m 2 ) conditions through high-speed photography technology. The dendritic fractal structure of its discharge trajectory reflects the non-linear diffusion characteristics of charges on the insulator surface; there is also literature that, based on the analysis of the discharge current waveform, proposed a transient gas breakdown model for brush discharge, indicating that its energy release is limited by the charge migration rate on the dielectric surface and the air breakdown threshold.

[0004] In order to accurately evaluate the powder ignition risk that may be caused by brush discharge, it is necessary to establish an electrostatic sensitivity evaluation system that can simulate real industrial conditions (such as specific temperature and humidity). To achieve this goal, a brush discharge simulation experimental device needs to be built to explore the energy coupling mechanism and the electrostatic discharge safety of powder materials during the discharge process. Summary of the Invention

[0005] The purpose of the present invention is to provide a brush discharge simulation experimental device based on a rotation mechanism that can operate automatically and be precisely controlled.

[0006] The present invention adopts the following technical solutions:

[0007] A brush discharge simulation experimental device based on a rotation mechanism, which includes a rotation support system; a feeding system, a corona spraying system, and a discharge system are evenly distributed above the circumference of the rotation support system.

[0008] Further, the rotary support system includes a turntable driven by a stepper motor, and a material carrying module that rotates with the turntable is arranged on the turntable. The material carrying module includes a metal backplane, a dielectric plate, and a flame-retardant insulating plate arranged in sequence from bottom to top. The metal backplane is fixedly connected to the turntable and grounded through a cable, and a circular sample groove is arranged on the flame-retardant insulating plate.

[0009] Further, the feeding system includes a conveying pipe, a spiral feeding valve arranged at the lower end of the conveying pipe, and a flared distributor arranged on the spiral feeding valve. The opening of the flared distributor is along the normal direction of the turntable.

[0010] Further, the corona spraying system includes a three-axis precision sliding table module, a high-voltage power supply, and a current-limiting resistor. A flange is connected to the end of the three-axis precision sliding table module. A needle tip array is arranged on the lower surface of the flange. The needle tip array, the flange, the current-limiting resistor, and the high-voltage power supply are connected in series in sequence.

[0011] Further, the discharging system includes an electric cylinder and a metal spherical electrode arranged at the end of the push rod of the electric cylinder. The metal spherical electrode moves along the normal direction of the turntable. The metal spherical electrode is connected to a data collector through a cable.

[0012] Further, the surface of the sample groove is treated by the corona discharge modification technology.

[0013] Further, the needle tip array includes a plurality of carbon fiber needles or metal gold needles, and is arranged in an equidistant matrix, concentric circles, and / or honeycomb structure.

[0014] Further, the data collector is an oscilloscope.

[0015] The beneficial effects of the present invention are as follows:

[0016] (1) An integrated powder processing platform is constructed based on the rotary support system to realize the automatic operation of the process flow.

[0017] (2) The corona spraying system uses multi-needle array corona discharge, and cooperates with the z-axis dynamic distance adjustment mechanism of the three-axis precision sliding table module to form a uniform deposition layer of charges on the surface of the workpiece. Cooperating with the high-voltage power supply and the current-limiting resistor, the amount of charge can be accurately adjusted.

[0018] (3) A discharging system is configured to realize the progressive approximation of the electrode along the normal direction, and combine with the high-voltage power supply (0-120 kV) and the data acquisition module to complete the controllable discharge cycle and data acquisition. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the present invention.

[0020] Among them, 1 is a stepper motor, 2 is a turntable, 3 is a metal backplane, 4 is a dielectric plate, 5 is a flame-retardant insulating plate, 6 is a sample groove, 7 is a delivery pipe, 8 is a spiral feeder valve, 9 is a flared distributor, 10 is a three-axis precision slide table module, 11 is a high-voltage power supply, 12 is a current-limiting resistor, 13 is a flange, 14 is a tip array, 15 is an electric cylinder, 16 is a metal spherical electrode, 17 is a cable, 18 is a data collector, and 19 is a box body. Specific embodiments

[0021] The technical solutions of the present invention will be described in detail below in conjunction with specific embodiments.

[0022] As Figure 1 shown, a brush-shaped discharge simulation experiment device based on a rotation mechanism is provided inside an experimental box body 19, and the experimental device includes a rotation support system; a feeding system, a corona spraying system, and a discharge system are evenly distributed above the circumference of the rotation support system.

[0023] The rotation support system includes a turntable 2 driven by a stepper motor 1. The turntable realizes reciprocating rotation under the drive of the stepper motor. The method of driving the turntable by a stepper motor is a prior art, including but not limited to connection by a shaft, connection by a coupling, gear transmission, or synchronous belt transmission. A material carrying module that rotates with the turntable 2 is provided on the turntable 2. The material carrying module includes a metal backplane 3, a dielectric plate 4, and a flame-retardant insulating plate 5 arranged in sequence from bottom to top. The metal backplane is made of stainless steel or aluminum alloy metal material, the dielectric plate is made of polytetrafluoroethylene material, and the flame-retardant insulating plate is made of epoxy resin material. A circular sample groove 6 is provided on the flame-retardant insulating plate 5. The sample groove 6 is surface-treated by a corona discharge modification technology, which is beneficial to forming a uniform powder layer with adjustable thickness. The metal backplane 3 is fixedly connected to the turntable 2 and grounded through a cable 17.

[0024] The feeding system includes a delivery pipe 7, a spiral feeder valve 8 provided at the lower end of the delivery pipe 7, and a flared distributor 9 provided on the spiral feeder valve 8. The opening of the flared distributor 9 is along the normal direction of the turntable 2, realizing uniform cloth feeding with controllable thickness of the powder material in the sample groove.

[0025] The corona spraying power system includes a three-axis precision slide table module 10, a high-voltage power supply 11, and a current-limiting resistor 12. The three-axis precision slide table module is a prior art technology that can accurately position in three-dimensional space, with X / Y / Z axis travel requirements of ±0.01 mm. The high-voltage power supply is adjustable from 0 to 120 kV, and the current-limiting resistor can be selected from 50 to 5000 kΩ according to usage needs, with the overvoltage protection threshold set at 120 kV. The end effector of the three-axis precision slide table module 10 is connected to a flange 13. A tip array 14 is provided on the bottom surface of the flange 13. The tip array 14 includes a number of carbon fiber needles or metal gold needles, arranged in an equidistant matrix, concentric circles, and / or a honeycomb structure. The tip array 14, flange 13, current-limiting resistor 12, and high-voltage power supply 11 are connected in series in sequence through a cable 17.

[0026] The discharge system includes an electric cylinder 15 and a metal spherical electrode 16 provided at the end of the electric cylinder push rod. The metal spherical electrode 16 moves along the normal direction of the turntable 2. The metal spherical electrode 16 is connected to a data collector 18 through a cable 17. The data collector 18 is specifically an oscilloscope for collecting voltage and current data during the discharge process.

[0027] The experimental device will be further described below in conjunction with the working process of the present invention.

[0028] The feeding system, corona spraying power system, and discharge system are respectively placed in three directions inside the test chamber and correspond to above the turntable. During use, the rotary support system starts to work, and the stepping motor drives the turntable to rotate. At the same time, the material carrying module is also rotated under the feeding system. At this time, the bell mouth distributor is aligned with the sample tank, and the powder sample is quantitatively released. The powder sample is evenly laid in the sample tank. Then, the rotary support system continues to rotate, and the sample tank rotates under the corona spraying power system. The flange and the tip array provided circumferentially at its bottom are connected to the current-limiting resistor and the high-voltage power supply. By adjusting the charging voltage, the distance between the tip array and the powder sample, and the charging time, the amount of charge obtained by the powder sample is controlled. After the spraying power process is completed, the rotary support system continues to rotate, and the sample tank rotates under the metal spherical electrode. By controlling the distance between the sample tank and the metal spherical electrode through the discharge system, brush discharge is achieved (in the implementation of brush discharge, the critical distance range between the sample tank and the metal spherical electrode is usually 1 to 3 mm, and specifically needs to be dynamically adjusted according to the electric field strength, medium characteristics, and discharge energy requirements. Physical conditions, brush discharge requires a local electric field strength ≥ 3×10 6Triggered at [[V / m]], at this time, the connected oscilloscope collects the voltage and current data during the discharge process to complete the experimental data acquisition. This experimental device can also set a high-speed camera in the box to capture the brush discharge morphology. In addition, this experimental device can also use a PLC, etc. to jointly control each module to achieve an automated experiment. After the experiment is over, the stepping motor rotates back to the starting position to prepare for the next experiment.

Claims

1. A brush discharge simulation experimental device based on a rotation mechanism, characterized in that, It includes a rotary support system; a feeding system, a corona spraying system, and a discharging system are evenly distributed above the circumference of the rotary support system.

2. The brush discharge simulation experimental device based on a rotation mechanism according to claim 1, characterized in that, The rotary support system includes a turntable (2) driven by a stepping motor (1). A material carrying module that rotates with the turntable (2) is arranged on the turntable (2). The material carrying module includes a metal backplane (3), a dielectric plate (4), and a flame-retardant insulating plate (5) arranged in sequence from bottom to top; the metal backplane (3) is fixedly connected to the turntable (2) and grounded through a cable (17), and a circular sample groove (6) is arranged on the flame-retardant insulating plate (5).

3. The brush discharge simulation experimental device based on a rotation mechanism according to claim 2, characterized in that, The feeding system includes a conveying pipe (7), a spiral feeding valve (8) arranged at the lower end of the conveying pipe (7), and a flared distributor (9) arranged on the spiral feeding valve (8). The opening of the flared distributor (9) is along the normal direction of the turntable (2).

4. The brush discharge simulation experimental device based on a rotation mechanism according to claim 3, wherein The corona spraying system includes a three-axis precision sliding table module (10), a high-voltage power supply (11), and a current-limiting resistor (12); a flange (13) is connected to the end of the three-axis precision sliding table module (10); a needle tip array (14) is arranged on the lower surface of the flange (13); the needle tip array (14), the flange (13), the current-limiting resistor (12), and the high-voltage power supply (11) are connected in series in sequence.

5. The brush discharge simulation experimental device based on a rotation mechanism according to claim 4, wherein, The discharging system includes an electric cylinder (15) and a metal spherical electrode (16) arranged at the end of the electric cylinder push rod. The metal spherical electrode (16) moves along the normal direction of the turntable (2); the metal spherical electrode (16) is connected to a data collector (18) through a cable (17).

6. The brush discharge simulation experimental device based on a rotation mechanism according to claim 5, characterized in that, The surface of the sample groove (6) is treated by a corona discharge modification technology.

7. The brush discharge simulation experimental device based on a rotation mechanism according to claim 6, characterized in that, The needle tip array (14) includes a number of carbon fiber needles or metal gold needles, and is arranged in an equidistant matrix, concentric circles, and / or a honeycomb structure.

8. The brush discharge simulation experimental device based on a rotation mechanism according to claim 7, characterized in that, The data collector (18) is an oscilloscope.

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