Device for eliminating static electricity in a pneumatic conveying system

Abstract

The utility model provides a kind of device for eliminating static in pneumatic conveying system, belong to pneumatic conveying equipment technical field.The device includes shell, ion wind generating unit (including ion wind import, ion wind generator, ion wind spray head), static electricity leads out unit (including connecting ring, ground chain), first flange, second flange and static electricity measuring device.Shell inside conveying passage diameter is consistent with existing pipeline, ion wind spray head is tangentially arranged and included angle 30-60 degrees, realize that ion wind and powder are fully mixed;Static electricity leads out unit removes residual static electricity by double grounding path;Static electricity measuring device monitors in real time and dynamically adjusts electricity consumption strategy.The electricity consumption efficiency of the device reaches more than 95%, does not affect material quality, installation and maintenance are convenient, can effectively solve the problem that the electricity consumption effect of prior art is poor, material is affected, installation is complex, applicable to flammable and explosive powder pneumatic conveying scene.

Description

Technical Field

[0001] This utility model relates to the field of pneumatic conveying equipment technology, specifically to a device for eliminating static electricity generated during the flow of powder materials in a pneumatic conveying system. This device is suitable for pneumatic conveying scenarios involving flammable, explosive, or easily adhering powders in industries such as chemical, pharmaceutical, and food, and can achieve efficient and safe elimination of static electricity during the conveying process. Background Technology

[0002] Pneumatic conveying systems are widely used in the long-distance or multi-point conveying of powder materials in industries such as chemical, pharmaceutical, food, and metallurgy due to their advantages of high conveying efficiency, small footprint, and easy automation control. During the operation of this system, powder particles (such as plastic particles, coal powder, food additives, etc.) flow at high speed in a closed pipe, which causes continuous friction with the inner wall of the pipe, and frequent collisions between particles. This process leads to the transfer of electrons on the surface of the powder particles, resulting in the accumulation of a large amount of electrostatic charge. If these static charges are not eliminated in time, they can cause multiple hidden dangers to the production process: at best, powder will adhere to the inner wall of the pipe due to electrostatic adsorption, gradually forming material accumulation. This will not only reduce the flow cross-section of the pipe and reduce the conveying efficiency, but also interfere with the detection accuracy of the flow metering equipment, leading to material measurement deviation. at worst, when the static charge accumulates to a certain level, it will form an electrostatic field in the pipe. If the field strength exceeds the breakdown field strength of air, it will generate electrostatic sparks. Especially when conveying flammable and explosive powders such as coal powder, polyethylene particles, and sulfur powder, electrostatic sparks can easily ignite or explode the flammable mixture in the pipe, causing fires or explosions, seriously threatening the safety of production equipment and the lives of operators.

[0003] To address the static electricity problem in pneumatic conveying systems, various static electricity elimination methods exist in the current technology, but all have significant shortcomings: Increasing air humidity during transport: This method increases air humidity by introducing water mist or steam into the transport airflow to enhance electrostatic discharge capacity, allowing the electrostatic charge on the surface of powder particles to be conducted to the pipe wall through the humid air. However, this method has drawbacks. High humidity environments can easily cause hygroscopic powders (such as salt, sucrose, and certain pharmaceutical intermediates) to deliquesce, or cause powder particles to clump together due to moisture adhesion. This not only seriously affects the physicochemical quality of the materials (such as causing pharmaceutical powders to deteriorate and food powders to clump and become unusable), but also exacerbates the adhesion and blockage of powders in the pipes, further reducing the stability of the transport system. For non-hygroscopic powders, the electrostatic elimination effect of this method is also very limited.

[0004] Grounded metal pipeline method: This method utilizes the conductivity of metal pipelines, connecting the pipeline to a grounding electrode via a grounding wire, allowing the electrostatic charge generated by friction between the powder and the pipeline to be conducted to the ground. However, this method only provides a basic electrostatic discharge path. When the powder transport volume is large and the flow rate is fast, the amount of electrostatic charge generated by the powder particles is far greater than the electrostatic conduction rate of the pipeline. Excess electrostatic charge will still accumulate in the pipeline. When the accumulation reaches a critical value, electrostatic sparks may still be generated locally in the pipeline (such as at pipeline bends or valve interfaces), which cannot meet the safety requirements for transporting flammable and explosive powders.

[0005] Single-blowing ion wind method: This method eliminates static electricity by blowing an airflow containing positive and negative ions (ion wind) into the pipeline, utilizing the neutralization reaction between the ions and the electrostatic charge on the surface of the powder particles. However, existing single-blowing ion wind devices have the following drawbacks: First, the direction and coverage of the ion wind are difficult to control precisely, which can easily lead to insufficient mixing between the ion wind and the powder particles, resulting in incomplete static neutralization in some areas. Second, if the ion concentration of the ion wind is too high or the spraying time is too long, it can cause the powder particle surface to adsorb an excessive amount of positive and negative ions, resulting in an "over-neutralization" phenomenon, which causes the powder particles to re-acquire electrostatic charges of the opposite polarity, making the static elimination effect unstable. In addition, existing ion wind devices are mostly fixed structures, requiring large-scale modifications such as cutting and welding of existing pneumatic conveying pipelines. This not only results in long construction cycles and high difficulty, but also leads to long-term shutdown of the conveying system, affecting production progress. Furthermore, subsequent maintenance requires the disassembly of a large number of pipeline components, resulting in high maintenance costs.

[0006] In addition, most existing static eliminators lack real-time monitoring capabilities, making it impossible to promptly grasp the accumulation of static charge in the pipeline. They can only operate continuously based on preset parameters, which not only wastes energy but also fails to dynamically adjust the static elimination strategy according to changes in static electricity. At the same time, some devices have poor sealing performance, making them prone to airflow leakage in high-pressure pneumatic conveying scenarios, further reducing conveying efficiency. Summary of the Invention

[0007] This utility model aims to solve the following technical problems: existing static electricity elimination methods either have poor elimination effects, easily affect material quality, or have unstable elimination effects; existing static electricity elimination devices are complex to install, requiring large-scale modifications to existing conveying systems, resulting in long construction periods, high maintenance costs, and poor adaptability; existing devices lack real-time static electricity monitoring functions, making it impossible to dynamically adjust the elimination strategy, which easily leads to energy waste and makes it difficult to ensure conveying safety; some devices have insufficient sealing performance, which easily leads to airflow leakage in high-pressure pneumatic conveying scenarios, affecting conveying efficiency.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution.

[0009] A device for eliminating static electricity in a pneumatic conveying system includes a housing, an ion wind generating unit, a static electricity discharge unit, a first flange, a second flange, and a static electricity measuring device. The housing has a conveying channel running through both ends, with a diameter consistent with that of an existing pneumatic conveying pipeline. The ion wind generating unit includes an ion wind inlet, an ion wind generator, and an ion wind nozzle, all connected sequentially via an internal airflow channel. The ion wind inlet is located on the side wall of the housing, and the ion wind nozzle is located on the inner wall of the housing. The static electricity discharge unit includes a connecting ring and a grounding chain, which are fixed together by conductive connectors to form a conductive path. The first and second flanges are fixed at both ends of the housing for connection to an existing pneumatic conveying pipeline. The static electricity measuring device includes a metal probe and a static electricity meter. The metal probe is installed at a pre-reserved interface in the housing and connected to the static electricity meter via a shielded wire.

[0010] In a preferred embodiment of this utility model, the shell has a cylindrical shape and multiple standardized installation interfaces are reserved on the side wall. Each installation interface has a sealing groove on its inner side, and a fluororubber sealing ring is embedded in the groove.

[0011] In a preferred embodiment of this utility model, the ion wind generator is an AC-powered ion wind generator or an airflow-driven electrostatic eliminator; the AC-powered ion wind generator is connected to an external 220V AC power supply and generates corona discharge through high-voltage electrodes; the airflow-driven electrostatic eliminator uses 0.4-0.8MPa compressed air as a power source and achieves air ionization through a vortex cavity and metal guide vanes.

[0012] In a preferred embodiment of this utility model, the ion air nozzle is arranged tangentially, with the injection direction consistent with the flow direction of the powder material, and the angle between the injection direction axis and the conveying pipe axis is 30 to 60 degrees.

[0013] In a preferred embodiment of this utility model, the number of ion air nozzles is set according to the diameter of the housing conveying channel: 3-4 nozzles are provided when the diameter is DN80-DN150, and 5-6 nozzles are provided when the diameter is DN150-DN250. All nozzles are evenly distributed along the circumferential direction of the inner wall of the housing, and the included angle between adjacent nozzles is equal.

[0014] In a preferred embodiment of this utility model, the nozzle of the ion air nozzle adopts a detachable threaded connection structure.

[0015] In a preferred embodiment of this utility model, the connecting ring is a copper alloy ring structure, which is fixed to the outside of the shell near the middle position by argon arc welding, and three grounding connection ports are evenly arranged on the outer side along the circumference; the grounding chain is a tin-plated copper chain, one end of which is fixed to the connecting ring interface by bolts, and the other end is connected to the underground grounding electrode by wiring terminals, and the grounding electrode is buried at a depth of not less than 1.5 meters.

[0016] In a preferred embodiment of this utility model, the inner sides of the first flange and the second flange are provided with conductive rings. The conductive rings are split semi-circular ring splicing structures with a thickness slightly greater than that of the graphite composite gasket. Multiple elastic contact pieces are evenly distributed along the circumferential direction on the outer edge of the conductive rings. The elastic contact pieces are 15mm long, 8mm wide, and 0.5mm thick, and extend outward at a 15-degree angle.

[0017] In a preferred embodiment of this utility model, the first flange and the second flange are each provided with four positioning studs on their outer sides. The positioning studs are 16mm in diameter and 50mm in length. One end is welded to the flange and the other end is a 60-degree apex conical structure. Each flange is equipped with two foldable clamping arms. The clamping arms are made of Q235 carbon steel and are connected to the flange by hinges. Rubber pads are provided on the inner side.

[0018] In a preferred embodiment of this utility model, the first flange and the second flange are fixed to the shell by submerged arc welding, and the sealing surface adopts a concave-convex surface design with a convex surface height of 3mm and a concave surface depth of 3mm; multiple bolt holes are evenly distributed along the circumference of the flange, and the number and diameter of the bolt holes are determined according to the nominal diameter of the flange.

[0019] Compared with the prior art, the beneficial technical effects of this utility model are as follows: This device utilizes tangentially arranged ion air nozzles, with the spray direction at a 30-60 degree angle to the pipeline axis, creating a spiral airflow trajectory that achieves comprehensive, dead-angle-free mixing with the powder material, achieving a charge neutralization efficiency of over 95%. Simultaneously, any residual static electricity after neutralization is completely eliminated through a dual grounding path consisting of a connecting ring, grounding chain, flange, and conductive ring, effectively preventing electrostatic sparks. Furthermore, this device eliminates static electricity without increasing air humidity; instead, it employs a physical method of ion air neutralization and metal grounding, avoiding powder deliquescence and agglomeration problems caused by high humidity environments, thus ensuring the physicochemical quality of the material. This makes it particularly suitable for industries with high material quality requirements, such as pharmaceuticals and food. The device achieves quick alignment with existing pipelines via positioning studs, and the foldable clamping arm enhances the stability of the flange connection, eliminating the need for cutting or welding modifications to existing pipelines. The ion air nozzles feature detachable threaded connections; only the nozzle itself needs replacement when clogged or worn. The device is equipped with an electrostatic measuring device that can monitor the electrostatic voltage in the pipeline in real time. When the electrostatic voltage is lower than the preset safety threshold, it will automatically reduce the output intensity of the ion wind generator or stop working to avoid energy waste; when the electrostatic voltage is higher than the threshold, it will automatically increase the output to ensure timely static discharge. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the static electricity elimination device in the pneumatic conveying system according to the first embodiment of this utility model; Figure 2 This is a schematic diagram of the arrangement structure of the ion air nozzle (8) on the inner wall of the housing (1) in this utility model; Figure 3 This is a schematic diagram of the connection structure between the first flange (6) or the second flange (7) and the conductive ring (9) in this utility model.

[0021] The labels for each figure are as follows: 1: shell, 2: ion wind generator, 3: ion wind inlet, 4: static electricity discharge unit, 41: connecting ring, 42: grounding chain, 5: static electricity measuring device, 6: first flange, 7: second flange, 8: ion wind nozzle, 9: conductive ring. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] like Figure 1 As shown, in the first embodiment of this utility model, a static electricity elimination device for a pneumatic conveying system is provided. This device aims to solve the problems of existing static electricity elimination technologies having limited effectiveness, cumbersome installation, and inconvenient maintenance. By integrating a dual static electricity elimination mechanism of ion wind neutralization and grounding conduction, coupled with a quick-clamping structure and real-time monitoring function, it achieves efficient and safe elimination of static electricity in the pneumatic conveying system.

[0025] The static elimination device in the pneumatic conveying system includes a housing 1, an ion wind generator 2, an ion wind inlet 3, a static electricity discharge unit 4, a static electricity measuring device 5, a first flange 6, a second flange 7, and an ion wind nozzle 8.

[0026] The housing 1 is the supporting component of the entire device. It has a conveying channel running through both ends inside. The diameter of the conveying channel is exactly the same as the diameter of the existing pneumatic conveying pipeline. For example, if the diameter of the existing pipeline is DN100, the diameter of the housing conveying channel is also DN100. This design can ensure that the powder material will not generate flow resistance due to the change of the channel diameter during the conveying process, and avoid material accumulation or sudden changes in conveying speed.

[0027] Preferably, the housing 1 has an overall cylindrical structure, and multiple standardized installation interfaces are reserved on the side wall of the housing 1. One interface is used to assemble the ion wind inlet 3, another interface is used to install the metal probe in the electrostatic measuring device 5, and another interface is used to fix the connecting ring 41 of the electrostatic discharge unit 4. Each installation interface has a sealing groove on its inner side, and an oil-resistant and wear-resistant fluororubber sealing ring can be embedded in the groove.

[0028] The ion wind generating unit is the component that achieves charge neutralization. It consists of three parts: ion wind inlet 3, ion wind generator 2, and ion wind nozzle 8. The three parts are connected in sequence through an internal airflow channel.

[0029] The ion air inlet 3 is located in the middle of the side wall of the housing 1, and its interface specifications match the output interface of the ion air generator 2, for example, using a PN1.6MPa, DN25 flange interface. The ion air inlet 3 is fixedly connected to the output end of the ion air generator 2 by bolts, and an asbestos gasket is placed between the connection surfaces to ensure the airtightness of the connection and prevent compressed air leakage during transportation.

[0030] Preferably, the ion wind generator 2 can be selected from two types according to the safety requirements and energy supply of the actual production scenario: one is a traditional AC-powered ion wind generator, which is powered by an external 220V AC power supply. The internal high-voltage electrode generates a corona discharge phenomenon, which ionizes the molecules in the air into positive and negative ions to form an ion wind; the other is an airflow electrostatic eliminator that does not require external power supply. This type of generator uses 0.4-0.8MPa compressed air commonly used in industrial production as a power source. When the compressed air flows through the special vortex cavity and metal guide vanes inside the generator, it will be ionized under the action of mechanical shear force and airflow disturbance, giving the air good conductivity and enabling it to carry a large number of positive and negative ions to form an ion wind.

[0031] The ion air nozzle 8 is installed on the inner wall of the housing 1 and is connected to the ion air inlet 3 through a pre-set circular airflow channel inside the housing 1. The inner diameter of the airflow channel is consistent with the inner diameter of the inlet of the ion air nozzle 8, for example, both are 20mm, to ensure that there is no significant pressure loss during the ion air delivery process.

[0032] See further Figure 2The ion air nozzle 8 is arranged tangentially, with its injection direction consistent with the flow direction of the powder material in the pneumatic conveying pipeline. Furthermore, the axis of the ion air injection direction forms an angle of 30 to 60 degrees with the axis of the pneumatic conveying pipeline. This angle design is the optimal range determined through multiple experiments: when the angle is less than 30 degrees, the contact area between the ion air and the powder material is small, resulting in insufficient mixing and a charge neutralization efficiency of less than 80%; when the angle is greater than 60 degrees, the ion air interferes with the flow direction of the powder, potentially causing localized airflow turbulence or even powder backflow; however, within the 30 to 60 degree range, the ion air can form a spiral airflow trajectory, achieving comprehensive and thorough mixing with the powder material flowing through the conveying channel, increasing the charge neutralization efficiency to over 95%.

[0033] More preferably, the number of ion air nozzles 8 is set according to the diameter of the housing conveying channel. Typically, a housing with a diameter of DN80-DN150 is equipped with 3-4 ion air nozzles, and a housing with a diameter of DN150-DN250 is equipped with 5-6 ion air nozzles. All nozzles are evenly distributed along the circumference of the inner wall of the housing, and the included angle between two adjacent nozzles is equal. For example, when there are 4 nozzles, the included angle is 90 degrees, ensuring that the ion air can evenly cover the entire cross-section of the conveying channel and avoid dead zones in the electrostatic discharge.

[0034] Schematic illustration: The nozzle of the ion air nozzle 8 adopts a detachable threaded connection structure. When the nozzle becomes clogged or worn, the operator only needs to use a wrench to unscrew the old nozzle and replace it with a new one, without having to disassemble the entire device.

[0035] The electrostatic discharge unit 4 serves as the second electrostatic discharge barrier of the device, used to conduct away the small amount of electrostatic charge remaining after neutralization by the ion wind, ensuring that the electrostatic charge is completely eliminated. It consists of two parts: a connecting ring 41 and a grounding chain 42, which are fixed by conductive connectors to form a continuous, low-resistance conductive path.

[0036] The connecting ring 41 is made of the same copper alloy as the housing and has a ring-shaped structure. Its inner diameter matches the outer diameter of the housing 1. For example, when the outer diameter of the housing is 159mm, the inner diameter of the connecting ring 41 is also 159mm. The connecting ring 41 is fixedly connected to the outer part of the housing near the center by argon arc welding. Three grounding chain 42 interfaces are evenly arranged along the circumference on the outer side of the connecting ring 41. Each interface is a cylindrical structure with internal threads and an inner diameter of 12mm, used to connect to one end of the grounding chain 42.

[0037] Preferably, the grounding chain 42 is a tin-plated copper chain with a single link length of 20mm. The overall length can be flexibly adjusted according to the actual height of the installation environment. For example, when the installation height of the device is 3 meters, the length of the grounding chain 42 is set to 3.2 meters to ensure that the other end of the grounding chain 42 can be reliably connected to the grounding electrode on the ground. One end of the grounding chain 42 is fixed to the interface of the connecting ring 41 by bolts, and a copper flat washer is placed between the bolts and the interface to enhance the conductive contact effect. The other end of the grounding chain 42 is connected to the grounding electrode through a terminal block. The grounding electrode is made of galvanized angle steel and is buried at a depth of not less than 1.5 meters underground.

[0038] like Figure 3 As shown, conductive rings 9 are provided on the inner sides of the first flange 6 and the second flange 7. Since the connecting ring 41 and the shell 1 are tightly electrically connected by welding, the static electricity on the surface of the shell 1 can be transferred not only to the grounding chain 42 through the connecting ring 41, but also to the conductive ring 9 on the inner side of the flange through the welded connection between the shell and the first flange 6 and the second flange 7. Then, the conductive ring 9 is transferred to the flange of the existing pneumatic conveying pipeline through the elastic contact piece, and finally discharged through the grounding system of the pipeline itself.

[0039] The first flange 6 and the second flange 7 are fixedly connected to the end faces of the shell 1 by submerged arc welding. The sealing surfaces of the flanges adopt a raised face design, with a raised face height of 3mm and a concave face depth of 3mm, which can effectively enhance the sealing effect and prevent air leakage. Multiple bolt holes are evenly distributed along the circumference of the first flange 6 and the second flange 7. The number and diameter of the bolt holes are determined according to the nominal diameter of the flange. For example, a flange with a nominal diameter of DN100 is provided with 8 bolt holes with a diameter of 18mm.

[0040] The conductive ring 9 is located inside the first flange 6 and the second flange 7, between the flange sealing surface and the graphite composite gasket. It employs a split structure, consisting of two identical semicircular rings joined together. The advantage of this split design is that installation does not require disassembling the existing pipeline flanges. The two semicircular rings are simply inserted from both sides of the pipeline flange and then bolted together to form a complete ring structure, shortening installation time. The conductive ring 9 is 3.5mm thick, slightly thicker than the graphite composite gasket. This design ensures that when the flanges are tightened with bolts, the conductive ring 9 can make tight contact with the end faces of both the pipeline flange and the shell flange under the preload of the bolts, eliminating contact gaps, ensuring unobstructed conductive paths, and preventing electrostatic discharge obstruction due to poor contact.

[0041] Multiple elastic contact pieces are evenly distributed along the circumference of the outer edge of the conductive ring 9. Each elastic contact piece is 15mm long, 8mm wide, and 0.5mm thick, extending outward at an angle of 15 degrees. When the flanges are aligned, the elastic contact pieces can fit tightly against the side of the existing pipe flange under their own elastic force, further enhancing the reliability of the conductive connection between the conductive ring 9 and the pipe flange. Even if the flange undergoes slight displacement due to airflow vibration during operation, the elastic contact pieces can always maintain contact with the pipe flange, preventing interruption of the conductive path.

[0042] More preferably, the static elimination device in the pneumatic conveying system is further equipped with positioning studs and clamping arms (not shown in the figure). The positioning studs are located on the outside of the first flange 6 and the second flange 7, with four positioning studs evenly distributed on each flange. The positioning studs have a diameter of 16 mm and a length of 50 mm. One end is welded to the flange, and the other end has a conical structure with a cone apex angle of 60 degrees. During installation, the positioning studs can be inserted into the corresponding positioning holes on the existing pipe flanges to quickly align the central axis of the device with the pipe, ensuring that the coaxiality error between the conveying channel of the shell and the axis of the pipe is less than 0.1 mm, thus avoiding obstruction of powder conveying or accelerated wear of the inner wall of the pipe due to installation deviation.

[0043] The clamping arms feature a foldable structure, with two clamping arms on each flange. The arms are made of Q235 carbon steel and are connected to the flange via hinges. After the device and pipe flange are initially secured with bolts, the clamping arms are unfolded and clamped onto the outside of the pipe flange. The free end of the clamping arm is then fixed to the flange with bolts, further enhancing the stability of the flange connection. Rubber pads are provided on the inner side of the clamping arms to prevent scratches on the pipe flange and to enhance clamping friction. When maintenance or disassembly is required, simply loosen the fixing bolts of the clamping arms, fold the arms, and unscrew the flange connection bolts to quickly remove the device from the pipeline. The entire disassembly process takes only about 30 minutes and will not cause prolonged disruption to the normal operation of the pneumatic conveying system.

[0044] The electrostatic measuring device 5 is used to monitor the electrostatic level of powder materials in the conveying channel in real time, providing feedback signals for the intelligent operation of the device, so as to adjust the working state of the ion wind generating unit in a timely manner according to the change of electrostatic voltage. It includes a metal probe and an electrostatic instrument, which are connected by a shielded wire.

[0045] In the static elimination device of the pneumatic conveying system, the two ends of the housing 1 are fixedly connected to the first flange 6 and the second flange 7 by submerged arc welding. The interface in the middle of the housing 1 is fixedly connected to the output end of the ion wind generator 2 by bolts. An asbestos sealing gasket is placed between the connection surfaces to ensure airtightness. Another interface is used to install the metal probe of the electrostatic measuring device 5. Another interface is fixed to the connecting ring 41 of the static discharge unit 4 by argon arc welding, forming a reliable conductive connection between the housing 1 and the connecting ring 41. The ion wind inlet 3 matches the flange interface of the output end of the ion wind generator 2 and is detachably fixed by bolts. The ion wind inlet 3 is directly connected to the ion wind nozzle 8 through the circular airflow channel inside the housing 1. In the static discharge unit 4, the connecting ring 41 is fixedly connected to the grounding chain 42 by a conductive connector to form a continuous conductive path. The other end of the grounding chain 42 is reliably connected to the underground grounding electrode through a terminal block. The first flange 6 and the second flange 7 are connected to the existing pipeline by bolts passing through the flange bolt holes, while the conductive ring 9 on the inner side of the flange is fitted between the pipeline flange and the shell flange through a split splicing structure. The metal probe of the electrostatic measuring device 5 is connected to the electrostatic instrument through a shielded wire.

[0046] When the pneumatic conveying system is started, the powder material flows along the existing conveying pipeline to the location of the device, and enters the conveying channel inside the shell 1 through the connection between the first flange 6 and the existing pipeline. At this time, the electrostatic measuring device 5 is put into operation first. Its metal probe penetrates into the conveying channel to capture the electrostatic voltage signal generated by the friction and collision between particles and between particles and the pipe wall during the flow of the powder material in real time. The signal is transmitted to the electrostatic instrument through the shielded wire. After processing the signal, the electrostatic instrument sends a working command to the ion wind generator 2 according to the preset electrostatic safety threshold.

[0047] Upon receiving the command, the ion wind generator 2 starts working according to the type of configuration on site: if it is an AC-powered ion wind generator, it is powered by an external 220V AC power supply, and the internal high-voltage electrodes generate corona discharge, ionizing the molecules in the air into a large number of positive and negative ions; if it is an airflow-driven static eliminator, it uses 0.4-0.8MPa industrial compressed air as a power source. When the compressed air flows through the internal vortex cavity and metal guide vanes, it is ionized under the action of mechanical shearing force and airflow disturbance, forming an ion wind carrying a large number of positive and negative ions. The generated ion wind enters the airflow channel inside the housing 1 through the ion wind inlet 3, which is fixedly connected to the output end of the ion wind generator 2, and then flows through the channel to the ion wind nozzles 8, which are evenly distributed on the inner wall of the housing, and is sprayed into the inside of the conveying channel through the nozzles.

[0048] The tangential arrangement and 30-60 degree injection angle of the ion air nozzle 8 create a spiral airflow trajectory after injection, achieving thorough mixing with the powder material flowing along the conveying channel. During the mixing process, the positive and negative ions in the ion air neutralize the electrostatic charge carried on the surface of the powder material, eliminating most of the electrostatic charge with a neutralization efficiency of over 95%. Any remaining electrostatic charge after neutralization is completely eliminated through a dual-pathway system: firstly, the residual charge is transferred through the metal material of the shell 1 to the welded connecting ring 41, then through the connecting ring 41 to the grounding chain 42, and finally conducted to the grounding electrode underground, where it is released into the ground; secondly, the electrostatic charge on the surface of the shell 1 is also transferred through the welded connection with the first flange 6 and the second flange 7 to the conductive ring 9 inside the flange. The conductive ring 9, through close contact with the existing pipe flange and the assistance of the elastic contact piece, transfers the electrostatic charge to the existing pneumatic conveying pipeline, where it is then discharged through the pipeline's own grounding system.

[0049] Throughout the operation, the electrostatic measuring device 5 continuously monitors the electrostatic level in the conveying channel. If the detected electrostatic voltage is lower than the preset safety threshold, it sends an adjustment command to the ion air generator 2 to reduce the ion air output intensity or suspend operation to avoid energy waste. If the detected electrostatic voltage is higher than the threshold, it instructs the ion air generator 2 to increase the output intensity to ensure timely neutralization of electrostatics. Simultaneously, the positioning studs ensure the coaxiality of the device and the pipeline, preventing powder conveying obstruction or increased pipe wall wear due to installation deviations. The stable connection between the clamping arm and the flange, as well as the sealing effect of each sealing structure, ensures stable operation of the device under high-pressure airflow without airflow leakage. The detachable ion air nozzle 8 allows for quick replacement by operators when nozzle blockage or wear is detected, without affecting normal system production. After the powder material has undergone electrostatic elimination, it continues to flow along the conveying channel of the shell 1, entering the next conveying stage through the connection between the second flange 7 and the subsequent pipeline. The entire electrostatic elimination process is continuous, efficient, and does not affect the normal conveying efficiency of the pneumatic conveying system.

[0050] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0051] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for eliminating static electricity in a pneumatic conveying system, characterized in that, The system includes a housing (1), an ion wind generating unit, an electrostatic discharge unit (4), a first flange (6), a second flange (7), and an electrostatic measuring device (5). The housing (1) has a conveying channel that runs through both ends, and the diameter of the conveying channel is the same as that of the existing pneumatic conveying pipeline. The ion wind generating unit includes an ion wind inlet (3), an ion wind generator (2), and an ion wind nozzle (8), which are connected in sequence through an internal airflow channel. The ion wind inlet (3) is located on the side wall of the housing (1), and the ion wind nozzle (8) is located on the inner wall of the housing (1). The electrostatic discharge unit (4) includes a connecting ring (41) and a grounding chain (42), which are fixed together by conductive connectors to form a conductive path. The first flange (6) and the second flange (7) are fixed at both ends of the housing (1) for connection with the existing pneumatic conveying pipeline. The electrostatic measuring device (5) includes a metal probe and an electrostatic meter. The metal probe is installed at the reserved interface of the housing (1) and connected to the electrostatic meter through a shielded wire.

2. The device for eliminating static electricity in a pneumatic conveying system according to claim 1, characterized in that, The shell (1) has a cylindrical shape and multiple standardized installation interfaces are reserved on the side wall. Each installation interface has a sealing groove on the inside, and a fluororubber sealing ring is embedded in the groove.

3. The device for eliminating static electricity in a pneumatic conveying system according to claim 2, characterized in that, The ion wind generator (2) is an AC-powered ion wind generator or an airflow-driven electrostatic eliminator; the AC-powered ion wind generator is connected to an external 220V AC power supply and generates corona discharge through high-voltage electrodes; the airflow-driven electrostatic eliminator uses 0.4-0.8MPa compressed air as a power source and achieves air ionization through a vortex cavity and metal guide vanes.

4. The device for eliminating static electricity in a pneumatic conveying system according to claim 3, characterized in that, The ion air nozzle (8) is arranged tangentially, with the injection direction consistent with the flow direction of the powder material, and the angle between the injection direction axis and the conveying pipeline axis is 30 to 60 degrees.

5. The device for eliminating static electricity in a pneumatic conveying system according to claim 4, characterized in that, The number of ion air nozzles (8) is set according to the diameter of the shell conveying channel: 3-4 nozzles are provided when the diameter is DN80-DN150, and 5-6 nozzles are provided when the diameter is DN150-DN250. All nozzles are evenly distributed along the circumferential direction of the inner wall of the shell, and the included angle between adjacent nozzles is equal.

6. The device for eliminating static electricity in a pneumatic conveying system according to claim 5, characterized in that, The nozzle of the ion air nozzle (8) adopts a detachable threaded connection structure.

7. The device for eliminating static electricity in a pneumatic conveying system according to claim 6, characterized in that, The connecting ring (41) is a copper alloy ring structure, which is fixed to the outside of the shell (1) near the middle position by argon arc welding. Three grounding chain (42) interfaces are evenly arranged on the outer side along the circumference. The grounding chain (42) is a tin-plated copper chain. One end is fixed to the connecting ring (41) interface by bolts, and the other end is connected to the underground grounding electrode by wiring terminals. The grounding electrode is buried at a depth of not less than 1.5 meters.

8. The device for eliminating static electricity in a pneumatic conveying system according to claim 7, characterized in that, The first flange (6) and the second flange (7) are provided with conductive rings (9) on their inner sides. The conductive rings (9) are split semi-circular ring splicing structures with a thickness slightly greater than that of the graphite composite gasket. Multiple elastic contact pieces are evenly distributed along the circumferential direction on the outer edge of the conductive rings (9). The elastic contact pieces are 15mm long, 8mm wide, and 0.5mm thick, and extend outward at a 15-degree angle.

9. The device for eliminating static electricity in a pneumatic conveying system according to claim 8, characterized in that, The first flange (6) and the second flange (7) are each provided with 4 positioning studs on the outside. The positioning studs are 16mm in diameter and 50mm in length. One end is welded to the flange and the other end is a 60-degree apex conical structure. Each flange is equipped with 2 foldable clamping arms. The clamping arms are made of Q235 carbon steel and are connected to the flange through hinges. The inner side is provided with a rubber pad.

10. The device for eliminating static electricity in a pneumatic conveying system according to claim 9, characterized in that, The first flange (6) and the second flange (7) are fixed to the shell (1) by submerged arc welding. The sealing surface adopts a concave-convex surface design with a convex surface height of 3mm and a concave surface depth of 3mm. Multiple bolt holes are evenly distributed along the circumference of the flange. The number and diameter of the bolt holes are determined according to the nominal diameter of the flange.

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