Powder brush type discharge electrostatic sensitivity test loading electrode and operation method thereof

Abstract

The invention provides a powder brush type discharge electrostatic sensitivity test loading electrode and an operation method thereof. A heat conduction coupling unit comprises a metal heating plate, a heat conduction insulating rubber layer and a polytetrafluoroethylene dielectric plate which are sequentially stacked from bottom to top; the polyimide sample tank is fixedly arranged in the middle of the upper surface of the polytetrafluoroethylene dielectric plate; a discharge test chamber for placing a powder sample is arranged in the polyimide sample tank; the temperature closed-loop control unit comprises a temperature controller, a voltage adaptation module and an infrared temperature measurement probe; the voltage adaptation module is used for providing multi-gear selectable working voltage for the metal heating plate, and the infrared temperature measurement probe is used for measuring the temperature of a powder sample in the polyimide sample groove in real time; and the temperature controller is used for setting the test temperature of the powder sample and comparing the temperature of the powder sample measured by the infrared temperature measuring probe with the test temperature so as to determine whether the metal heating plate is heated or not. According to the invention, wide-range temperature coupling and multi-voltage adaptive temperature adjustment of the powder sample can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of evaluating the electrostatic sensitivity of powder materials under brush discharge conditions, and particularly relates to a loading electrode for testing the electrostatic sensitivity of powder brush discharge and an operation method thereof. Background Art

[0002] During the production, storage, and transportation of powder materials, electrostatic discharge (especially brush discharge) is one of the main risk factors leading to combustion and explosion accidents. Evaluating the electrostatic sensitivity of powders is a key means to assess their safety, but there are significant limitations in the existing technologies. Most traditional loading electrodes for electrostatic sensitivity testing are designed based on room temperature environments and cannot simulate the dynamic influence of temperature changes on the electrostatic sensitivity of powders under actual working conditions. Research on the mechanism of powder electrostatic discharge shows that an increase in temperature will significantly change the surface charge distribution state of powders and affect the energy release characteristics of brush discharge. For example, for powder materials such as explosives, the electrostatic sensitivity threshold may decrease significantly due to enhanced molecular activity in a high-temperature environment. However, the existing loading electrodes have insufficient temperature adaptability, with problems such as low temperature control accuracy and a narrow voltage adaptation range. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a loading electrode for testing the electrostatic sensitivity of powder brush discharge and an operation method thereof in view of the deficiencies of the existing technologies, adopting a wide temperature range regulation and multi-voltage adaptation design to facilitate the measurement of the electrostatic sensitivity of powder brush discharge under different temperature conditions.

[0004] To solve the above technical problem, the content of the present invention includes:

[0005] A loading electrode for testing the electrostatic sensitivity of powder brush discharge, comprising:

[0006] A heat conduction coupling unit, which includes a metal heating plate, a heat-conducting insulating glue layer, and a polytetrafluoroethylene dielectric plate stacked in sequence from bottom to top;

[0007] A polyimide sample cell, which is fixedly arranged at the middle position on the upper surface of the polytetrafluoroethylene dielectric plate; and the inside of the polyimide sample cell is a discharge test chamber for placing a powder sample;

[0008] A temperature closed-loop control unit, which includes a temperature controller, a voltage adaptation module, and an infrared temperature measurement probe; the voltage adaptation module is used to provide a multi-gear selectable working voltage to the metal heating plate, and the infrared temperature measurement probe is used to measure the temperature of the powder sample in the polyimide sample cell in real time; the temperature controller is used to set the test temperature T of the powder sample and compare the temperature of the powder sample measured by the infrared temperature measurement probe with the test temperature T to determine whether to heat the metal heating plate.

[0009] Further, a grounding electrode interface and two terminal posts are provided on the side of the metal heating plate. The grounding electrode interface is directly grounded through a grounding wire, and the grounding resistance value is ≤ 0.1 Ω. One output terminal of the voltage adaptation module is connected to one terminal of the relay of the temperature controller. The other terminal of this relay is connected to one terminal post, and the other output terminal of the voltage adaptation module is connected to the other terminal post.

[0010] Further, the infrared temperature measurement probe is arranged above the side of the polyimide sample tank.

[0011] Further, the output voltage range of the voltage adaptation module is 24 - 440 V, and it is specifically configured with five standard voltage outputs of 24 V, 110 V, 220 V, 380 V, and 440 V. The switching response time between each gear is ≤ 0.5 s.

[0012] Further, the polyimide sample tank is in a flat cylindrical shape, and its peripheral wall is fixedly connected to the polytetrafluoroethylene dielectric plate through a plurality of polytetrafluoroethylene bolts.

[0013] Further, the height range of the polyimide sample tank is 0.05 - 1 mm.

[0014] Further, the thickness range of the polytetrafluoroethylene dielectric plate is 0.5 - 10 mm.

[0015] Further, the thermally conductive insulating adhesive layer is composed of a silicone rubber - based composite material, and its thickness range is 0.5 - 2 mm.

[0016] An operation method of a loading electrode for powder brush - type discharge electrostatic sensitivity testing includes the following steps:

[0017] S1. Fill the powder sample to be measured into the discharge test chamber of the polyimide sample tank;

[0018] S2. Set the target test temperature T through the temperature controller, select the working voltage gear of the voltage adaptation module, and energize the metal heating plate to heat the powder sample in the discharge test chamber;

[0019] S3. Collect the temperature data of the powder sample in the discharge test chamber in real - time through the infrared temperature measurement probe. When the temperature of the powder sample reaches the target temperature T, the temperature controller disconnects the connection between the voltage adaptation module and the metal heating plate to stop heating the powder sample.

[0020] Further, the target test temperature T is: 25 °C ≤ T ≤ 350 °C.

[0021] The beneficial effects of the present invention are:

[0022] The present invention adopts a wide - range temperature coupling and multi - voltage adaptation design, which can significantly improve the accuracy of powder electrostatic sensitivity testing. Through the synergistic effect of a metal heating plate and a thermally conductive insulating adhesive layer, the temperature of the powder sample can be continuously adjusted in the range from room temperature (25 °C) to 350 °C to simulate the real electrostatic risks in industrial high - temperature working conditions (such as chemical reactors, drying equipment). A multi - gear selectable working voltage is provided to the metal heating plate through a voltage adaptation module. Brief Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of the loading electrode for powder brush - type discharge electrostatic sensitivity testing of the present invention;

[0024] In the figure: 1, polyimide sample tank; 2, polytetrafluoroethylene dielectric plate; 3, thermally conductive insulating adhesive layer; 4, metal heating plate; 5, grounding electrode interface; 6, terminal; 7, infrared temperature - measuring probe; 8, discharge ball electrode. Detailed Embodiments

[0025] To facilitate the understanding of the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0026] Embodiment 1: As Figure 1 shown, the present invention provides a loading electrode for powder brush - type discharge electrostatic sensitivity testing, including:

[0027] A heat conduction coupling unit, which includes a metal heating plate 4, a thermally conductive insulating adhesive layer 3, and a polytetrafluoroethylene dielectric plate 2 stacked in sequence from bottom to top;

[0028] A polyimide sample tank 1, which is fixedly arranged at the middle position on the upper surface of the polytetrafluoroethylene dielectric plate 2; and the inside of the polyimide sample tank 1 is a discharge test chamber for placing the powder sample;

[0029] A temperature closed - loop control unit, which includes a temperature controller, a voltage adaptation module, and an infrared temperature - measuring probe 7; the voltage adaptation module is used to provide a multi - gear selectable working voltage to the metal heating plate 4, the infrared temperature - measuring probe 7 is arranged above the side of the polyimide sample tank 1 for real - time measuring the temperature of the powder sample in the polyimide sample tank 1; the temperature controller is used to set the test temperature T of the powder sample and compare the temperature of the powder sample measured by the infrared temperature - measuring probe 7 with the test temperature T to determine whether to heat the metal heating plate 4.

[0030] The metal heating plate 4 is used to support the whole device and be grounded, heating the powder sample in the polyimide sample groove 1 on the polytetrafluoroethylene dielectric plate 2 to make its temperature reach the set test temperature T. The middle thermal conductive insulating glue layer 3 is used to bond and fix the polytetrafluoroethylene dielectric plate 2 on the metal heating plate 4 and achieve heat conduction and insulation. The top polytetrafluoroethylene dielectric plate 2 cannot be a metal or other conductive plate, which is used to enable brush discharge to occur when the discharge ball electrode 8 discharges after the powder sample is charged. This sandwich-type heat conduction coupling structure can not only achieve efficient heating of the powder sample, but also reliably achieve the effects of insulation and brush discharge.

[0031] The side of the metal heating plate 4 is provided with a grounding electrode interface 5 and two terminal posts 6. The grounding electrode interface 5 is directly grounded through a grounding wire, and the grounding resistance value ≤ 0.1Ω to effectively suppress stray current. One output terminal of the voltage adaptation module is connected to one terminal of the relay of the temperature controller, the other terminal of this relay is connected to one terminal post 6, and the other output terminal of the voltage adaptation module is connected to the other terminal post 6.

[0032] The relay of the temperature controller serves as the heating switch of the metal heating plate 4. When the infrared temperature measurement probe 7 measures that the temperature of the powder sample has not reached the test temperature T, the two terminals of the relay of the temperature controller will be automatically connected, so that the voltage adaptation module is connected to the metal heating plate 4 and provides it with working voltage, and the metal heating plate 4 is in the heating state; when the infrared temperature measurement probe 7 measures that the temperature of the powder sample reaches the test temperature T, the relay of the temperature controller will be automatically disconnected, that is, the voltage adaptation module is disconnected from the metal heating plate 4, so the metal heating plate 4 stops heating.

[0033] The output voltage range of the voltage adaptation module is 24 - 440V, specifically configured with five standard voltage outputs of 24V, 110V, 220V, 380V, and 440V, and the switching response time between each gear ≤ 0.5s.

[0034] The polyimide sample groove 1 is in a flat cylindrical shape, and its peripheral wall is fixedly connected to the polytetrafluoroethylene dielectric plate 2 through a plurality of polytetrafluoroethylene bolts.

[0035] The height range of the polyimide sample groove 1 is 0.05 - 1mm. This height value is positively correlated with the particle size of the measured powder sample. The height of the polyimide sample groove 1 depends on the particle size of the measured powder sample. When the particles are larger, the height should be larger, and when the particles are smaller, the height can be lower.

[0036] The thickness range of the polytetrafluoroethylene dielectric plate 2 is 0.5 - 10 mm. This thickness value is positively correlated with the explosion force of the measured powder sample. The thickness of the polytetrafluoroethylene dielectric plate 2 is determined by the explosion force of the measured powder sample. If the explosion force of the measured powder sample is large, the polytetrafluoroethylene dielectric plate 2 should be thicker; otherwise, it can be thinner.

[0037] The thermally conductive insulating adhesive layer 3 is composed of a silicone rubber-based composite material, and its thickness range is 0.5 - 2 mm. The thickness of the thermally conductive insulating adhesive layer 3 depends on the thermal conductivity and bonding viscosity of the insulating adhesive used, and it is necessary to ensure good thermal conductivity and firm adhesion.

[0038] Example 2: An operation method of a loading electrode for powder brush-type discharge electrostatic sensitivity testing, including the following steps:

[0039] S1. Fill the measured powder sample into the discharge test chamber of the polyimide sample tank 1;

[0040] S2. Set the target test temperature T through the temperature controller, and select the working voltage gear of the voltage adaptation module. The metal heating plate 4 is energized to heat the powder sample in the discharge test chamber;

[0041] S3. Real-time collect the temperature data of the powder sample in the discharge test chamber through the infrared temperature measurement probe 7. When the temperature of the powder sample reaches the target temperature T, the temperature controller disconnects the connection between the voltage adaptation module and the metal heating plate 4, and stops heating the powder sample.

[0042] During the electrostatic sensitivity test, heating the powder sample is carried out after the electrospraying process. Use the corona electrospray brush connected to the high-voltage power supply to electrospray charge the powder sample in the discharge test chamber; then heat the powder sample through the metal heating plate 4 to simulate the real electrostatic risk of industrial high-temperature working conditions.

[0043] Finally, achieve brush-shaped discharge through the discharge ball electrode 8 set directly above the polyimide sample tank 1, and simultaneously collect the voltage and current data of the discharge process by using the data acquisition card connected to the discharge ball electrode 8.

[0044] The target test temperature T is: 25°C ≤ T ≤ 350°C. During the electrostatic sensitivity test, use the temperature controller to set the test temperature T of the powder sample, and the temperature control accuracy is ±1°C. Usually, start from a relatively low temperature, conduct discharge, collect data and calculate the sensitivity value, then gradually increase the temperature by one step, and conduct discharge, collect data and calculate the sensitivity value again until the required highest temperature, and also complete data collection and calculation.

[0045] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A powder brush type discharge electrostatic sensitivity test loading electrode, characterized in that include: A heat conduction coupling unit, comprising a metal heating plate (4), a heat-conducting insulating adhesive layer (3) and a polytetrafluoroethylene dielectric plate (2) stacked in sequence from bottom to top; A polyimide sample slot (1) is fixedly arranged at a middle position of an upper surface of a polytetrafluoroethylene dielectric plate (2); and the interior of the polyimide sample slot (1) is a discharge test chamber for placing a powder sample; A temperature closed-loop control unit comprises a temperature controller, a voltage adaptor module and an infrared temperature measuring probe (7); the voltage adaptor module is used to provide a metal heating plate (4) with a multi-level selectable operating voltage, and the infrared temperature measuring probe (7) is used to measure the temperature of a powder sample in a polyimide sample tank (1) in real time; the temperature controller is used to set a test temperature T of the powder sample, and compare the powder sample temperature measured by the infrared temperature measuring probe (7) with the test temperature T to determine whether the metal heating plate 4 is heated or not.

2. The powder brush type discharge electrostatic sensitivity test loading electrode according to claim 1, characterized in that: A grounding electrode interface (5) and two terminals (6) are provided on the side of the metal heating plate (4); the grounding electrode interface (5) is directly grounded via a grounding wire, and the grounding resistance value is ≤0.1Ω; an output end of the voltage adaptation module is connected to a terminal of a relay of the temperature controller, another terminal of the relay is connected to a terminal (6), and another output end of the voltage adaptation module is connected to another terminal (6).

3. The powder brush type discharge electrostatic sensitivity test loading electrode according to claim 1, characterized in that: The infrared temperature measuring probe (7) is arranged on the upper side of the polyimide sample tank (1).

4. The powder brush type discharge electrostatic sensitivity test loading electrode according to claim 1, characterized in that: The output voltage range of the voltage adapter module is 24-440V, and is specifically configured with five standard voltage outputs of 24V, 110V, 220V, 380V, and 440V, and the switching response time between each gear is ≤0.5s.

5. The powder brush type discharge electrostatic sensitivity test loading electrode according to claim 1, characterized in that: The polyimide sample tank (1) is in the shape of a flat cylinder, and its peripheral wall is fixedly connected to the polytetrafluoroethylene medium plate (2) via a plurality of polytetrafluoroethylene bolts.

6. The powder brush type discharge electrostatic sensitivity test loading electrode according to claim 1, characterized in that: The height of the polyimide sample groove (1) ranges from 0.05 to 1 mm.

7. The powder brush type discharge electrostatic sensitivity test loading electrode according to claim 1, characterized in that: The thickness of the polytetrafluoroethylene medium plate (2) is in the range of 0.5-10 mm.

8. The powder brush type discharge electrostatic sensitivity test loading electrode according to claim 1, characterized in that: The thermally conductive insulating adhesive layer (3) is made of a silicone rubber-based composite material and has a thickness ranging from 0.5 to 2 mm.

9. A method for operating a loading electrode for a powder brush type discharge electrostatic sensitivity test, characterized in that The following steps are involved: S1. Filling the powder sample to be tested into the discharge test chamber of the polyimide sample tank (1); S2. The target test temperature T is set by the temperature controller, and the working voltage position of the voltage adapter module is selected. The metal heating plate (4) is powered on to heat the powder sample in the discharge test chamber; S3. The temperature data of the powder sample in the discharge test chamber is collected in real time by using an infrared temperature measuring probe (7). When the temperature of the powder sample reaches the target temperature T, the temperature controller disconnects the voltage adapter module from the metal heating plate (4) and stops heating the powder sample.

10. The operating method according to claim 9, characterized in that: The target test temperature T is: 25°C ≤ T ≤ 350°C.

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