Vacuum dynamic sealing structure of plasma gun for powder preparation

Abstract

The utility model belongs to the technical field of plasma rotating electrode powder manufacturing equipment, and relates to a vacuum dynamic sealing structure of a plasma gun for powder manufacturing, which comprises an external powder blocking module and a dynamic sealing module, the external powder blocking module consists of a first powder blocking plate, a powder blocking ring and an insulating powder blocking plate, the first powder blocking plate is fixed at the top of a plasma gun body to form an arc-shaped shielding surface, and the dynamic sealing module is fixed at the top of the plasma gun body. The powder retaining ring coaxially sleeves the positive electrode of the plasma gun body and forms an annular gap type powder blocking structure with the insulating powder retaining plate; the dynamic sealing module is sequentially provided with a dynamic sealing installation metal cylinder, an insulating cylinder and a sealing assembly from outside to inside in the radial direction of the plasma gun body, the insulating cylinder and the dynamic sealing installation metal cylinder form a step-shaped sealing structure, and vacuum sealing and electrical isolation are achieved between the dynamic sealing module and the external powder blocking module through bakelite and an O-shaped sealing ring. The vacuum dynamic sealing structure provided by the utility model has the advantages of powder isolation, reliable sealing, no burning loss short circuit and no need of vacuum grease auxiliary sealing lubrication.

Description

Technical Field

[0001] This utility model belongs to the technical field of plasma rotating electrode powder making equipment, and relates to a plasma for powder making.

[0002] Gun vacuum dynamic sealing structure. Background Technology

[0003] In recent years, powder metallurgy technology has continued to develop, and plasma rotating electrode atomization (PREP) technology has also been constantly innovating. This technology has unparalleled advantages over other powder preparation technologies in preparing spherical metal powders with ultra-low interstitial element content. The prepared metal powders are characterized by high sphericity, few satellite powders, and almost no hollow powders. Currently, metal powders prepared by this technology have become recognized as high-quality raw materials in advanced manufacturing fields such as additive manufacturing and hot isostatic pressing.

[0004] As a core component of PREP equipment, the plasma gun provides a heat source for the melting process by generating a high-temperature plasma arc. Its unique heat generation mechanism dictates that the equipment operates under high voltage and high current conditions. During the melting process, the plasma gun needs to be adjusted vertically and horizontally in real time according to the melting state of the high-speed rotating bar stock. Simultaneously, because the powder preparation process is conducted entirely in an inert protective gas atmosphere, the insulation performance and dynamic sealing structure quality of the plasma gun play a crucial role in the operational stability of the equipment.

[0005] During the operation of PREP equipment, plasma gun system failure is a relatively difficult technical problem. The main reasons are: (1) Metal powder generated by centrifugal atomization during powder preparation is prone to accumulate on the surface of the gun body that extends into the furnace, causing short circuit between the gun body and the furnace wall; (2) As the gun body moves, it invades the dynamic sealing structure and causes short circuit. The short circuit will not only cause the gun body and dynamic sealing structure to burn and leak, but the impurities generated by burning and carbonization will also contaminate the metal powder after entering the furnace, resulting in the scrapping of the entire batch of powder; (3) After the metal powder enters the dynamic sealing structure, it will aggravate the wear of the gun body surface, damage the oil seal lip, and cause the equipment to leak. In severe cases, the oil seal structure will be damaged and stuck, causing the gun body's front and rear displacement mechanism to fail; (4) The vacuum dynamic sealing structure needs to be lubricated with vacuum grease to maintain the vacuum environment. During the movement of the gun body, some grease will be carried into the furnace, causing powder to adhere to the surface of the gun body, further increasing the risk of powder intrusion into the sealing structure, and at the same time, it will also cause grease to overflow and contaminate the metal powder. If the above-mentioned failure occurs, it will cause the smelting process to be interrupted, and the furnace must be opened to vent the gas for emergency repairs. This will not only seriously affect the production efficiency of the equipment, but also cause significant economic losses.

[0006] In view of this, this utility model is hereby proposed. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the prior art by designing a plasma gun vacuum dynamic sealing structure that combines external powder blocking, internal insulating material and sealing ring. This structure has the advantages of isolating powder, reliable sealing, no burn-out short circuit, and no need for vacuum grease-assisted sealing and lubrication.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This utility model provides a vacuum dynamic sealing structure for a plasma gun used in powder preparation, including: an external powder-blocking module and a dynamic sealing module.

[0010] The external powder blocking module consists of a first powder blocking plate, a powder blocking ring, and an insulating powder blocking plate. The first powder blocking plate is fixed to the top of the plasma gun body to form an arc-shaped shielding surface. The powder blocking ring is coaxially sleeved on the front anode of the plasma gun body and forms an annular gap-type powder blocking structure with the insulating powder blocking plate.

[0011] The dynamic sealing module is provided with a dynamic sealing mounting metal cylinder, an insulating cylinder and a sealing assembly in sequence from the outside to the inside along the radial direction of the plasma gun body. The insulating cylinder and the dynamic sealing mounting metal cylinder form a stepped sealing structure. The sealing assembly includes a TC skeleton oil seal, a UN oil seal, an insulating support ring and a dustproof and powder-scraping ring in sequence along the direction of the plasma gun body near the anode.

[0012] The dynamic sealing module and the external powder-blocking module achieve vacuum sealing and electrical isolation through insulating bakelite and O-rings.

[0013] Furthermore, the first powder baffle is in the shape of an arc-shaped brim, and the arc radius R of the arc-shaped brim satisfies R=1.2D±0.05D with the diameter D of the plasma gun body.

[0014] Furthermore, the gap between the inner wall of the powder-blocking ring and the plasma gun body is 3-5mm, the outer diameter of the powder-blocking ring is 1.5-2 times the diameter of the plasma gun body, and there is a gap between the powder-blocking ring and the first powder-blocking plate.

[0015] Furthermore, the width of the dustproof scraping ring in contact with the plasma gun body is 1-2mm, and the material of the dustproof scraping ring is PU.

[0016] Furthermore, the insulating support ring is a cone-angle-less support ring structure. The TC skeleton oil seal, UN oil seal, and insulating support ring are all installed inside the insulating cylinder, forming a sealing structure that is radially symmetrical along the plasma gun body, consisting of two TC skeleton oil seals, two UN oil seals, and one insulating support ring.

[0017] Furthermore, the O-ring includes a first O-ring and a second O-ring. The insulating bakelite is sealed to the dynamic sealing mounting metal cylinder by the second O-ring, and the dynamic sealing mounting metal cylinder and the insulating cylinder are sealed by the first O-ring.

[0018] Furthermore, an insulating fastener is installed on the outside of the insulating bakelite. After the insulating fastener is fixed to the dynamic sealing installation metal cylinder by connecting bolts, an insulating dust baffle is fitted on the insulating bakelite to form a double sealing isolation structure.

[0019] Furthermore, a sealing lip is provided on the UN oil seal, and the angle of the sealing lip is (30-60)°, preferably 30°, 45° and 60°.

[0020] Furthermore, the dust-proof scraping ring is installed in the groove formed by the insulating bakelite and the plasma gun body.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This utility model uses an external powder-blocking module to physically shield and protect the gun body exposed in the atomization chamber, blocking a large amount of metal powder in the atomization chamber and preventing it from falling onto the gun body and accumulating, thus achieving the anti-accumulation function on the outside of the plasma gun body.

[0023] 2. This utility model achieves the powder scraping and anti-intrusion function of the sealed structure by setting a powder scraping and dust removal ring at the front end of the sealed structure, so that the powder is scraped off by the powder scraping and dust removal ring when the gun body moves back and forth, preventing the powder from being carried into the sealed structure.

[0024] 3. This utility model embeds heat-resistant insulating materials such as insulating bakelite and insulating dust baffle into the flange of the original metal sealing ring mounting cylinder, which completely isolates and insulates the installation positions of the sealing ring and bakelite, preventing powder from entering the sealing ring and conducting with the dynamic sealing mounting metal cylinder to cause burn-out, thus realizing the insulating function of the sealing structure.

[0025] 4. This utility model also uses a sealing component with a large sealing surface, good rigidity, and lip that is not easily damaged for auxiliary sealing, to ensure sealing and smooth movement under vacuum grease-free conditions, and to achieve vacuum grease-free dynamic sealing function. The sealing structure prevents powder intrusion, thereby improving the lifespan of the plasma gun body.

[0026] 5. Since the plasma gun body surface of this utility model is free of vacuum grease, the risk of powder contamination is eliminated; the designed dynamic sealing module is stable and free from displacement failure, which greatly increases the number of powders that can be continuously melted by multiples; in addition, the vacuum dynamic sealing structure of the plasma gun is easy to disassemble and assemble, improving the replacement efficiency.

[0027] 6. Based on the inherent characteristics of the plasma gun body, this utility model redesigns the front-end structure of the plasma gun body to ensure that during the melting process, the front end of the plasma gun body will not burn out of the phenolic resin due to arcing or excessively high temperature of the attached powder, causing short circuits in the equipment and preventing the phenolic resin material from falling off and affecting product quality, thereby protecting the service life of the plasma gun body. At the same time, it avoids the need for cleaning the plasma gun body, greatly improving production efficiency, and eliminates the need for furnace opening and cleaning during the melting process, significantly reducing production costs. Attached Figure Description

[0028] The accompanying drawings are incorporated in and form part of this specification, and together with the description, serve to explain the principles of this invention.

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the overall structure of the vacuum dynamic sealing structure of the plasma gun for powder making according to this utility model;

[0031] Figure 2 for Figure 1 A magnified view of a section of the central I area;

[0032] Figure 3 for Figure 1 Enlarged view of a section in part II;

[0033] Figure 4 This is a schematic diagram of the structure of the dustproof scraping ring in this utility model;

[0034] Figure 5 for Figure 4 Schematic diagram of the cross-sectional structure along the AA direction;

[0035] Figure 6 This is a schematic diagram of the insulating cylinder in this utility model;

[0036] Figure 7 for Figure 6 Schematic diagram of the cross-sectional structure in the middle BB direction;

[0037] Figure 8 This is a schematic diagram of the insulating bakelite structure in this utility model;

[0038] Figure 9 for Figure 8 A schematic diagram of the cross-sectional structure along the CC direction.

[0039] Among them, 1-first powder baffle plate; 2-powder baffle ring; 3-plasma gun body; 4-dynamic seal mounting metal cylinder; 5-UN oil seal; 6-insulating support ring; 7-insulating cylinder body; 8-TC skeleton oil seal; 9-first O-ring seal; 10-second O-ring seal; 11-connecting bolt; 12-insulating fastener; 13-insulating powder baffle plate; 14-insulating bakelite; 15-dustproof powder scraper ring. Detailed Implementation

[0040] Exemplary embodiments will be described in detail below. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this invention. Rather, they are merely examples consistent with some aspects of this invention as detailed in the appended claims.

[0041] Reference Appendix Figure 1-9 As shown, this utility model provides a vacuum dynamic sealing structure for a plasma gun used in powder preparation, including: an external powder blocking module and a dynamic sealing module. The dynamic sealing module and the external powder blocking module achieve vacuum sealing and electrical isolation of the plasma gun through insulating bakelite 14 and O-rings.

[0042] According to an embodiment of this utility model, the O-ring includes a first O-ring 9 and a second O-ring 10. The insulating bakelite 14 and the dynamic sealing mounting metal cylinder 4 are sealed by the second O-ring 10, and the dynamic sealing mounting metal cylinder 4 and the insulating cylinder 7 are sealed by the first O-ring 9. Since the insulating bakelite 14, the O-ring, and the insulating cylinder 7 are all made of insulating materials, they can completely isolate and insulate the metal powder and the dynamic sealing mounting metal cylinder 4, preventing the powder from entering the O-ring and conducting with the dynamic sealing mounting metal cylinder 4, thus achieving the insulation function of the sealing system.

[0043] According to an embodiment of this utility model, the external powder-blocking module consists of a first powder-blocking plate 1, a powder-blocking ring 2, and an insulating powder-blocking plate 13. The first powder-blocking plate 1 is fixed to the top of the plasma gun body 3 to form an arc-shaped shielding surface. The first powder-blocking plate 1 is in the shape of an arc-shaped brim, and the arc radius R of the arc-shaped brim satisfies R=1.2D±0.05D with the diameter D of the plasma gun body 3. The powder-blocking ring 2 is coaxially sleeved on the front anode of the plasma gun body 3 and forms an annular gap-type powder-blocking structure with the insulating powder-blocking plate 13. The gap between the inner wall of the powder-blocking ring 2 and the plasma gun body 3 is 3-5mm, the outer diameter of the powder-blocking ring 2 is 1.5-2 times the diameter of the plasma gun body 3, and there is a gap between the powder-blocking ring 2 and the first powder-blocking plate 1, so that the upper end of the shielding ring 2 cannot touch the first powder-blocking plate 1. With the above design, the first powder-blocking plate 1 and the powder-blocking ring 2 can prevent most of the metal powder during the atomization process from falling directly onto the plasma gun body 3.

[0044] According to an embodiment of this utility model, the dynamic sealing module is provided with a dynamic sealing mounting metal cylinder 4, an insulating cylinder 7, and a sealing assembly sequentially from the outside to the inside along the radial direction of the plasma gun body 3. The insulating cylinder 7 and the dynamic sealing mounting metal cylinder 4 form a stepped sealing structure. One end of the insulating cylinder 7 and the dynamic sealing mounting metal cylinder 4 are fixed by a gun body flange, and the other end is fixed by bolts through an insulating fastener 12. The sealing assembly includes, sequentially along the direction of the plasma gun body 3 near the anode, a TC skeleton oil seal 8, an UN oil seal 5, an insulating support ring 6, and a dustproof and powder-scraping ring 15.

[0045] According to an embodiment of this utility model, the width of the dustproof scraping ring 15 in contact with the plasma gun body 3 is 1-2mm. The dustproof scraping ring 15 is made of PU, which has good elasticity and hardness, and can be PU with a Shore D50 or higher.

[0046] According to an embodiment of this utility model, the dustproof scraping ring 15 is installed in the groove formed by the insulating bakelite 14 and the plasma gun body 3. During installation, the dustproof scraping ring 15 can be pressed into the insulating bakelite 14 by a wave spring.

[0047] According to an embodiment of this utility model, the insulating support ring 6 is a cone-angle-less support ring structure. The TC skeleton oil seal 8, UN oil seal 5, and insulating support ring 6 are all installed inside the insulating cylinder 7. A sealing structure symmetrical along the radial direction of the plasma gun body 3 is formed by two TC skeleton oil seals 8, two UN oil seals 5, and one insulating support ring 6, i.e., installed in the order of TC skeleton oil seal 8 → UN oil seal 5 → insulating support ring 6 → UN oil seal 5 → TC skeleton oil seal 8. In actual use, the number of TC skeleton oil seals 8, UN oil seals 5, and insulating support ring 6 can be increased or decreased according to the actual size of the insulating cylinder 7 to achieve good sealing performance of the sealing assembly within the insulating cylinder 7. The UN oil seal 5 is provided with a sealing lip with an angle of (30-60)°.

[0048] According to an embodiment of the present invention, an insulating fastener 12 is installed on the outer side of the insulating bakelite 14. After the insulating fastener 12 is fixed to the dynamic sealing installation metal cylinder 4 by connecting bolts 11, an insulating dust baffle 13 is sleeved on the insulating bakelite 14. The insulating dust baffle 13 is fixedly connected to the insulating fastener 12 by threads to form a double sealing isolation structure.

[0049] The working principle of the vacuum dynamic sealing structure of the plasma gun for powder making of this utility model is as follows:

[0050] Because the exposed portion of the plasma gun body 3 within the atomization chamber accumulates metal powder on the equipment wall as the number of bars melted increases during the melting process, potentially causing short circuits, an anti-accumulation device is installed on the outside of the plasma gun body 3. Specifically, an arc-shaped powder-blocking "brim"-like first powder-blocking plate 1 is designed and added to the upper end of the plasma gun body 3 to form an overhead shield, preventing most of the metal powder ejected into the air by the rotating atomized bar from directly falling onto the plasma gun body 3. Secondly, a nozzle powder-blocking ring 2 is installed at the anode on the front side of the plasma gun body 3. During the melting process, this not only prevents metal powder carried into the surface of the plasma gun body 3 by the front airflow but also significantly reduces losses caused by overheating and burning of the sealing front end due to reverse arcing. Then, the fine metal powder adsorbed on the surface and wall of the plasma gun body 3 by the airflow will enter the sealing structure of the plasma gun body 3 as it moves. The sealing and anti-intrusion structure achieves the powder scraping function by adding a relatively hard insulating dustproof scraping ring 15 at the front end of the dynamic sealing structure. During the movement of the ion gun body 3, it can scrape off a large amount of powder adsorbed on the ion gun body 3, preventing the powder from entering the interior of the sealing structure of the ion gun body 3. Next, the insulation function is achieved through the design of the dynamic sealing installation metal cylinder 4 in the new sealing structure: the insulating cylinder 7. The sealing components are directly installed inside the insulating cylinder 7, and the insulating cylinder 7 and the dynamic sealing installation metal cylinder 4 form a stepped seal, which not only ensures the reliability of the seal but also ensures the overall insulation of the ion gun body 3, solving the problem of short circuit burnout. For the problem of vacuum grease and fine powder sticking together on the plasma gun body 3 and being unable to be scraped off by the powder scraper ring, the original Russian-made equipment's skeleton oil seal, special-shaped oil seal, and cone-angle bakelite structure were abandoned. A new combination design of TC skeleton oil seal 8, UN oil seal 5, and cone-angle-free insulating support ring 6 was adopted. The TC skeleton oil seal 8 plays the main sealing role, and the UN oil seal has good sealing lip rigidity and plays an auxiliary sealing role. The seal is reliable and will not be damaged or jammed due to insufficient lubrication. The insulating support ring 6 is used between the TC skeleton oil seal 8 and the UN oil seal 5, while reducing the assembly compression amount, and completely realizing a dynamic sealing structure without vacuum lubrication grease.

[0051] The steps for using the vacuum dynamic sealing structure of the plasma gun for powder preparation of this utility model include the following:

[0052] When the powder melting preparation production begins, the plasma gun 3 will move back and forth and up and down to align the plasma arc flame with the end face of the high-speed rotating base material bar. After reaching the designated position, the plasma gun 3 remains stationary, and the base material bar continues to be fed to complete the melting.

[0053] During the smelting process, the high-speed rotating bar atomizes into metal powder through centrifugal force. Under the combined action of centrifugal force, gravity, and circulating airflow in the furnace, the powder falls around the plasma gun body 3 and is blocked by the first powder baffle plate 1 and the powder baffle ring 2. Smaller powder particles will enter the area around the gun body through the gap between the first powder baffle plate 1 and the powder baffle ring 2 and the unprotected area at the bottom of the plasma gun body 3 under the influence of the airflow and centrifugal force in the furnace. They will accumulate and adhere to the surface of the plasma gun body 3 and be isolated by the insulating powder baffle plate 13 and the insulating bakelite 14. Since the insulating powder baffle plate 13 and the insulating bakelite 14 are both insulating materials, there will be no short circuit or burn-out.

[0054] When the bar stock melting is complete, the plasma gun body 3 is activated and moved back and forth while the sealing structure remains stationary. As the plasma gun body moves back and forth, some of the powder accumulated on the surface of the plasma gun body can be scraped off by the dust scraper ring 15 and fall into the furnace. A small amount of powder enters the dynamic sealing module. The first O-ring 9 and the second O-ring 10 prevent the small amount of powder from entering the dynamic sealing installation metal cylinder 4 through the gaps in the insulating bakelite 14, which could cause a short circuit and burn. The fine powder entering the insulating cylinder 7 is blocked by the sealing lip of the UN oil seal 5 and cannot enter. This structure can melt multiple furnaces without burn. Only the dust scraper ring 15 needs to be removed periodically for cleaning to achieve the functions of isolating powder, reliable sealing, no burn and short circuit, and no need for vacuum grease-assisted sealing and lubrication.

[0055] The above description is merely a specific embodiment of this utility model, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0056] It should be understood that this utility model is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of this utility model is limited only by the appended claims.

Claims

1. A vacuum dynamic sealing structure for a plasma gun used in powder preparation, characterized in that, include: External powder-blocking module and dynamic sealing module, The external powder blocking module consists of a first powder blocking plate (1), a powder blocking ring (2) and an insulating powder blocking plate (13). The first powder blocking plate (1) is fixed on the top of the plasma gun body (3) to form an arc-shaped shielding surface. The powder blocking ring (2) is coaxially sleeved on the front anode of the plasma gun body (3) and forms an annular gap-type powder blocking structure with the insulating powder blocking plate (13). The dynamic sealing module is provided with a dynamic sealing mounting metal cylinder (4), an insulating cylinder (7) and a sealing assembly in sequence from the outside to the inside along the radial direction of the plasma gun body (3). The insulating cylinder (7) and the dynamic sealing mounting metal cylinder (4) form a stepped sealing structure. The sealing assembly includes a TC skeleton oil seal (8), an UN oil seal (5), an insulating support ring (6) and a dustproof and powder-scraping ring (15) in sequence along the direction of the plasma gun body (3) near the anode. The dynamic sealing module and the external powder-blocking module achieve vacuum sealing and electrical isolation through insulating bakelite (14) and O-ring seals.

2. The vacuum dynamic sealing structure for a plasma gun used in powder preparation according to claim 1, characterized in that, The first powder baffle (1) is in the shape of an arc-shaped brim, and the arc radius R of the arc-shaped brim satisfies R=1.2D±0.05D with the diameter D of the plasma gun body (3).

3. The vacuum dynamic sealing structure for a plasma gun used in powder preparation according to claim 1, characterized in that, The gap between the inner wall of the powder blocking ring (2) and the plasma gun body (3) is 3-5mm. The outer diameter of the powder blocking ring (2) is 1.5-2 times the diameter of the plasma gun body (3), and there is a gap between the powder blocking ring (2) and the first powder blocking plate (1).

4. The vacuum dynamic sealing structure for a plasma gun used in powder preparation according to claim 1, characterized in that, The width of the dustproof scraping ring (15) in contact with the plasma gun body (3) is 1-2mm, and the material of the dustproof scraping ring (15) is PU.

5. The vacuum dynamic sealing structure for a plasma gun used in powder preparation according to claim 1, characterized in that, The insulating support ring (6) is a cone-angle-free support ring structure. The TC skeleton oil seal (8), UN oil seal (5) and insulating support ring (6) are all installed inside the insulating cylinder (7). The sealing structure is composed of two TC skeleton oil seals (8), two UN oil seals (5) and one insulating support ring (6) and is radially symmetrical along the plasma gun body (3).

6. The vacuum dynamic sealing structure for a plasma gun used in powder preparation according to claim 1, characterized in that, The O-ring includes a first O-ring (9) and a second O-ring (10). The insulating bakelite (14) is sealed with the second O-ring (10) and the dynamic sealing mounting metal cylinder (4). The dynamic sealing mounting metal cylinder (4) and the insulating cylinder (7) are sealed with the first O-ring (9).

7. The vacuum dynamic sealing structure for a plasma gun used in powder preparation according to claim 1, characterized in that, An insulating fastener (12) is installed on the outside of the insulating bakelite (14). After the insulating fastener (12) is fixed to the dynamic sealing installation metal cylinder (4) by connecting bolts (11), an insulating dust baffle (13) is fitted on the insulating bakelite (14) to form a double sealing isolation structure.

8. The vacuum dynamic sealing structure for a plasma gun used in powder preparation according to claim 1, characterized in that, A sealing lip is provided on the UN oil seal (5), and the angle of the sealing lip is (30-60)°.

9. The vacuum dynamic sealing structure for a plasma gun used in powder preparation according to claim 1, characterized in that, The dustproof scraping ring (15) is installed in the groove formed by the insulating bakelite (14) and the plasma gun body (3).

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