Sintering zone isolation system of vacuum degreasing sintering furnace

Abstract

The invention discloses a sintering area isolation system of a vacuum degreasing sintering furnace, which relates to the technical field of vacuum degreasing sintering furnaces and comprises a sealing box arranged in a furnace body and graphite doors for sealing two ends of the sealing box. An air guide plate is arranged inside the sealing box and on the inner side of the graphite door, and the periphery of the air guide plate is in sealing connection with the inner wall of the sealing box to divide the inner side of the graphite door into an air inlet diffusion area and a sealing box sintering area; a gas guide hole is formed in the gas guide plate, so that gas directionally and quantitatively flows into the sintering area from the gas inlet diffusion area; the air guide plate is connected with a pre-tightening structure used for providing pre-tightening force for pressing the seal. Reliable isolation between the gas inlet diffusion area and the sintering area of the sealing box is achieved through the gas guide plate and the pre-tightening structure of the gas guide plate, it is guaranteed that process gas can only enter the sintering area in a directional, quantitative and controllable mode through the gas guide holes, the uniformity and stability of the process atmosphere in the sintering area are effectively improved, and therefore the sintering quality of products is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum debinding sintering furnace, in particular to a sintering zone isolation system of a vacuum debinding sintering furnace. BACKGROUND

[0002] The vacuum debinding sintering furnace is a key equipment for removing binder (debinding or dewaxing) and high-temperature sintering of blank workpieces in the powder metallurgy, ceramic and other industrial fields. In the process of partial pressure sintering, process gas needs to be introduced into the furnace to maintain a specific atmosphere. In the scheme known to the inventors, the vacuum debinding sintering furnace usually includes a sealed box located inside the furnace body, which is closed at both ends by graphite doors. Process gas is introduced into the sealed box through a pipeline.

[0003] However, in actual application, the above-mentioned scheme has a significant defect: inside the sealed box, the gas guide plate (or similar component) for guiding the distribution of gas often lacks a reliable and durable sealing structure between the gas guide plate and the inner wall of the sealed box. This results in a considerable amount of gas entering the sintering zone irregularly and directly from the gap between the periphery of the gas guide plate and the inner wall of the box when it reaches the gas guide plate, in addition to the part that enters the sintering zone through the designed holes on the gas guide plate. This gas "bypassing" phenomenon causes uneven flow, flow rate and distribution of the process atmosphere in the sintering zone, and poor atmosphere stability. The direct consequence is that the sintering environment at different positions in the same furnace, or even different layers on the same material plate, is different, ultimately leading to inconsistent sintering quality of the products, such as uneven color and large fluctuations in dimensional accuracy. In addition, the existing structure also lacks an effective pressing and sealing mechanism for the gas guide plate, and the sealing effect is prone to decay during long-term operation or thermal expansion and contraction of the equipment, further exacerbating the above-mentioned problems.

[0004] Therefore, there is an urgent need for a technical solution that can effectively isolate the sintering zone and ensure that process gas can only enter the sintering zone uniformly and stably through a predetermined path. SUMMARY

[0005] The purpose of the present application is to provide a sintering zone isolation system of a vacuum debinding sintering furnace to solve the problems existing in the prior art and effectively isolate the sintering zone, ensuring that process gas can only enter the sintering zone uniformly and stably through a predetermined path.

[0006] To achieve the above-mentioned purpose, the present application provides the following scheme: A sintering zone isolation system of a vacuum debinding sintering furnace, comprising a sealed box arranged in the interior of a furnace body and graphite doors closing both ends of the sealed box; in the interior of the sealed box, a gas guide plate is arranged on the inner side of the graphite door, a sealing connection is formed between the periphery of the gas guide plate and the inner wall of the sealed box, thereby separating the area on the inner side of the graphite door into a gas inlet diffusion zone close to the graphite door and a sealed box sintering zone close to the interior of the sealed box; the gas guide plate is provided with gas guide holes for directional flow of gas from the gas inlet diffusion zone to the sealed box sintering zone; the gas guide plate is further connected with a gas guide plate pre-tightening structure for providing a pre-tightening force to the gas guide plate to press the periphery of the gas guide plate against the inner wall of the sealed box.

[0007] In an exemplary embodiment, a circumferential sealing step is arranged on the inner wall of the sealed box, and the periphery of the gas guide plate abuts against the sealing step to achieve face sealing; the gas guide plate pre-tightening structure comprises a pressing structure pressing against the outer periphery of the gas guide plate and an elastic force applying element providing a pressing force to the pressing structure.

[0008] In an exemplary embodiment, the sealing step is arranged on the sealed box upper plate, the sealed box lower plate, the sealed box left plate and the sealed box right plate of the sealed box; the gas guide plate at the rear end of the sealed box is directly fixed to the sealing step through a locking member penetrating through the pressing structure, and the gas guide plate at the front end of the sealed box is pre-tightened in linkage with the graphite door through the gas guide plate pre-tightening structure.

[0009] In an exemplary embodiment, the gas guide plate pre-tightening structure is any one of the following: Scheme I: comprising a first pressing ring, an elastic pressing strip fixed to the first pressing ring and a pre-tightening bolt mounted on the graphite door, a pre-tightening force is generated by pressing the elastic pressing strip through the pre-tightening bolt; Scheme II: comprising a second pressing ring with an inclined surface and an inclined pressing ring elastic pressing strip fixed to the second pressing ring, a pre-tightening force is generated by pressing the inclined pressing ring elastic pressing strip by closing the graphite door; Scheme III: comprising a third pressing ring, a spring column mounted on the third pressing ring and a third pressing ring spring sleeved on the spring column, a pre-tightening force is generated by compressing the third pressing ring spring by closing the graphite door; Scheme IV: comprising a fourth pressing ring and a fourth pressing ring elastic sheet arranged on the fourth pressing ring and the graphite door, the fourth pressing ring elastic sheet arranged on the fourth pressing ring and the fourth pressing ring elastic sheet arranged on the graphite door form an angle therebetween, a pre-tightening force is generated by pressing the two fourth pressing ring elastic sheets mounted on the fourth pressing ring and the graphite door against each other; Scheme five: comprising a fifth pressing ring, a pre-tightening shaft connected with the fifth pressing ring, and a linear driving device driving the pre-tightening shaft, and the pressing force is dynamically adjusted by the linear driving device; Scheme six: comprising a fourth pressing ring, a fourth pressing ring elastic sheet connected with the fourth pressing ring, a pre-tightening shaft connected with the fourth pressing ring elastic sheet, and a linear driving device driving the pre-tightening shaft, and the pressing force is dynamically adjusted by the linear driving device.

[0010] In an exemplary embodiment, in the scheme five and the scheme six, the pre-tightening shaft passes through the corresponding hole on the graphite door and is connected with the output end of the linear driving device; and the linear driving device is installed outside the furnace body.

[0011] In an exemplary embodiment, the sintering area of the sealed box is provided with a material plate for carrying workpieces, an upper baffle is arranged between the upper plate of the sealed box and the uppermost material plate, and a lower baffle is arranged between the lower plate of the sealed box and the lowermost material plate; the side edges of the upper baffle and the lower baffle are in contact with the corresponding end of the gas guide plate.

[0012] In an exemplary embodiment, the sintering area of the sealed box is divided into two front and rear areas, each area is provided with a corresponding upper baffle and lower baffle, the upper baffles in the two areas are connected by elastic members, and the lower baffles in the two areas are also connected by elastic members; the elastic members can drive the side edges of the upper baffles or the lower baffles to always press the corresponding gas guide plates.

[0013] In an exemplary embodiment, the material plates are arranged in the front and rear areas respectively, and there is a gap between the front and rear areas; the lower plate of the sealed box is provided with a dewaxing pipe corresponding to the gap for discharging gas.

[0014] In an exemplary embodiment, a first cavity is formed between the upper baffle and the upper plate of the sealed box, and a second cavity is formed between the lower baffle and the lower plate of the sealed box; the upper plate of the sealed box is provided with an upper safety valve communicating with the first cavity, and the lower plate of the sealed box is provided with at least one lower safety valve communicating with the second cavity.

[0015] In an exemplary embodiment, the lower safety valve comprises at least one first lower safety valve and at least one second lower safety valve, the opening pressure of the first lower safety valve is smaller than that of the second lower safety valve, and the first lower safety valve is closer to the dewaxing pipe in the horizontal direction than the second lower safety valve.

[0016] The present application has the following technical effects relative to the prior art: 1. The sintering zone and the gas inlet diffusion zone are effectively isolated: by setting the gas guide plate inside the graphite door, and making the reliable sealing connection between the circumference and the inner wall of the sealing box, the space inside the graphite door is successfully physically separated into two independent areas of the gas inlet diffusion zone and the sealing box sintering zone. This structure fundamentally eliminates the possibility of process gas directly and disorderly leaking into the sealing box sintering zone from the gap around the gas guide plate, laying the foundation for accurate control of the atmosphere.

[0017] 2. Ensure the directionality and controllability of the process gas flow: on the basis of effective isolation, the clean process gas entering the gas inlet diffusion zone is forced to enter the sealing box sintering zone only through the gas guide holes specially designed on the gas guide plate, the size and number of which can be adjusted. This realizes the directional and quantitative control of the gas flow path, so that the gas can flow through the workpiece in layers and uniformly according to the process requirements, greatly improving the uniformity and stability of the atmosphere distribution in the sintering zone.

[0018] 3. Provide durable and reliable sealing protection: by setting the gas guide plate pre-tightening structure, the gas guide plate can be actively and continuously provided with a pre-tightening force that presses the circumference against the inner wall of the sealing box. Not only does it compensate for the machining and assembly tolerances, but it also effectively offsets the stress generated by the different thermal expansion coefficients of various components during high-temperature sintering, maintaining the tight contact of the sealing surface, thereby ensuring the long-term reliability and stability of the isolation effect and extending the maintenance cycle. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The structure diagram of the sintering zone isolation system of the vacuum debinding sintering furnace disclosed in a specific embodiment of the present application; Figure 2 The enlarged view of part A in the figure; Figure 1 Figure 3 The enlarged view of part B in the figure; Figure 1 Figure 4 The enlarged view of part C in the figure; Figure 1 Figure 5 The structure diagram of the gas guide plate in the figure; Figure 1 Figure 6.1 The structure diagram of the front gas guide plate pre-tightening device scheme one; Figure 6.2 ​​​​Structure diagram of the second pre-tightening device for the front air guide plate; Figure 6.3 Structure diagram of the third pre-tightening device for the front air guide plate; Figure 6.4 Structure diagram of the fourth pre-tightening device for the front air guide plate; Figure 6.5 Structure diagram of the fifth pre-tightening device for the front air guide plate; Figure 6.6 Structure diagram of the sixth pre-tightening device for the front air guide plate; Figure 7.1 Structure diagram of the first installation mode of the upper baffle and the elastic member; Figure 7.2 Structure diagram of the second installation mode of the upper baffle and the elastic member; Figure 7.3 Structure diagram of the third installation mode of the upper baffle and the elastic member; 1, furnace body; 2, heat preservation cylinder; 3, sealing box; 3.1, upper plate of the sealing box; 3.2, lower plate of the sealing box; 4, graphite door; 5, inner air inlet pipe; 6, outer air inlet pipe; 7, dewaxing pipe; 8, outer air outlet pipe; 9, air guide plate compression strip; 10, first lower safety valve; 11, second lower safety valve; 12, upper safety valve; 13, upper baffle; 14, lower baffle; 15, air guide plate; 16, first compression ring; 17, fixing bolt; 18, elastic compression strip; 19, pre-tightening bolt; 20, material plate; 21, second compression ring; 22, elastic member; 23, inner air inlet pipe locking nut; 24, elastic compression strip for inclined compression ring; 25, first cavity; 26, second cavity; 27, spring; 28, elastic sheet; 29, support rod; 30, third compression ring; 31, spring for the third compression ring; 32, spring stand; 33, fourth compression ring; 34, support rod for the fourth compression ring; 35, elastic sheet for the fourth compression ring; 36, fifth compression ring; 37, pre-tightening shaft; 38, air cylinder; 39, electric cylinder. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings of the embodiments of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] The purpose of the present application is to provide a sintering zone isolation system of a vacuum debinding sintering furnace to solve the problems existing in the prior art, which can effectively isolate the sintering zone and ensure that the process gas can only enter the sintering zone uniformly and stably through the preset path.

[0023] In order to make the above-mentioned purposes, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0024] Please refer to Figures 1 to 7.3 The present embodiment provides a sintering zone isolation system of a vacuum debinding sintering furnace, which comprises a sealed box 3 arranged inside a furnace body 1 and graphite doors 4 closing both ends of the sealed box 3; inside the sealed box 3, a gas guide plate 15 is arranged on the inner side of the graphite door 4, and a sealing connection is formed between the periphery of the gas guide plate 15 and the inner wall of the sealed box 3, so as to divide the area on the inner side of the graphite door 4 into an air inlet diffusion zone close to the graphite door and a sealed box sintering zone close to the inside of the sealed box 3; the gas guide plate 15 is provided with gas guide holes for directing the flow of gas from the air inlet diffusion zone to the sealed box sintering zone; the gas guide plate 15 is further connected with a gas guide plate pre-tightening structure for providing the gas guide plate 15 with a pre-tightening force for pressing the periphery of the gas guide plate 15 against the inner wall of the sealed box 3.

[0025] Specifically, please refer to Figure 1 The furnace body 1 is provided with a heat preservation cylinder 2, and the inside of the heat preservation cylinder 2 is a sealed box 3. The sealed box 3 is usually made of high-temperature-resistant and high-strength materials such as special alloys or composite materials, and the openings at both ends are tightly sealed by openable graphite doors 4 to form a basically sealed cavity. In order to complete the process, the upper two sides of the sealed box 3 are provided with inner air inlet pipes 5 for introducing high-purity process gas (such as nitrogen, argon or hydrogen-nitrogen mixed gas) into the box, and the upper part of the furnace body 1 is provided with outer air inlet pipes 6. The lower middle part of the sealed box 3 is provided with a dewaxing pipe 7, and the lower part of the furnace body 1 is provided with an outer exhaust pipe 8 for discharging debinding products and waste gas. In addition, the sealed box 3 is provided with a pressure protection device, including a lower safety valve on its lower plate and an upper safety valve 12 on its upper plate, for balancing the pressure difference between the inside and outside of the sealed box 3 when vacuumizing, gas charging or internal pressure is abnormal, preventing structural damage.

[0026] Inside the sealed box 3, a gas guide plate 15 is arranged on the inner side of the graphite door 4. The periphery of the gas guide plate 15 is sealingly connected with the inner wall of the sealed box 3, so as to divide the space on the inner side of the graphite door 4 into an air inlet diffusion zone (including a front air inlet diffusion zone and a rear air inlet diffusion zone) close to the graphite door 4 and a sealed box sintering zone close to the middle part of the sealed box 3.

[0027] After the process gas enters the air inlet diffusion zone from the inner air inlet pipe 5, it can only enter the sealed box sintering zone through the pre-set gas guide holes on the gas guide plate 15, and the structure of the gas guide plate 15 is as follows Figure 5The size, number and distribution of the air guide holes can be customized according to the process requirements to achieve directional, quantitative and layered delivery of the gas to the sintering zone.

[0028] Please refer to Figure 2 、 3 , 4, to achieve the above sealing connection, a preferred embodiment is to set a surrounding sealing step on the inner wall of the sealing box 3, including the inner side of the sealing box upper plate 3.1, the sealing box lower plate 3.2, the sealing box left plate and the sealing box right plate. The outer edge size of the air guide plate 15 matches it, and when installed, its circumference directly abuts on the step plane to realize face sealing with large contact area, so as to improve the sealing effect and bearing stability.

[0029] For the fixation and compression of the air guide plate 15, the air guide plate pre-tightening structure is used. The air guide plate pre-tightening structure includes a compression structure compressed on the outer circumference of the air guide plate 15 and an elastic force element providing compression force to the compression structure.

[0030] The air guide plate 15 located at the rear end of the sealing box 3, as it is not involved in the conventional loading and unloading operation, can be fixed in a simple and rigid manner, such as Figure 3 As shown, only a compression structure such as four air guide plate compression bars 9 can be used to press the back of the air guide plate 15, and the air guide plate compression bars 9 are locked on the box body of the sealing box 3 by bolts, so as to directly and firmly fix it on the sealing step without using an elastic force element.

[0031] For the air guide plate 15 at the front end, in order to facilitate loading, unloading and maintenance after the graphite door 4 is opened, its sealing compression force needs to be linked with the opening and closing action of the graphite door 4 and can adapt to certain adjustment requirements, so the air guide plate pre-tightening structure used for the air guide plate at the front end needs an elastic force element linked with the graphite door 4.

[0032] The implementation scheme of the air guide plate pre-tightening structure can include but is not limited to the following schemes: Scheme one: please refer to Figure 6.1 The air guide plate pre-tightening structure includes a first compression ring 16, an elastic compression strip 18 fixed on the first compression ring 16 and a pre-tightening bolt 19 installed on the graphite door 4, and the pre-tightening bolt 19 extrudes the elastic compression strip 18 to generate pre-tightening force; Specifically, the elastic pressing strip 18 is installed on the first pressing ring 16 through the fixing bolt 17. The elastic pressing strip 18 can be made of high-elasticity CC composite material (carbon fiber composite) or other high-temperature-resistant and high-elasticity materials. According to the actual sintering condition of the product, two elastic pressing strips 18 can be installed on each side of the first pressing ring 16, or the elastic pressing strips 18 can be installed only on the left and right sides of the first pressing ring 16. The pre-tightening bolt 19 is installed on the graphite door 4. After the graphite door 4 is installed, the pre-tightening bolt 19 extrudes the elastic pressing strip 18, and the elastic pressing strip 18 provides a rebound force after being deformed under stress, so that the first pressing ring 16 is extruded to press the air guide plate 15, that is, the air guide plate 15 is pre-tightened. The pre-tightening bolt 19 can also adjust the thread depth according to the actual sintering condition of the product, that is, adjust the pre-tightening force, and adjust the pre-tightening degree of the air guide plate 15 and the sealing box 3.

[0033] Scheme two: please refer to Figure 6.2 , the air guide plate pre-tightening structure includes a second pressing ring 21 with a slope and a slope pressing ring elastic pressing strip 24 fixed on the second pressing ring 21. A pre-tightening force is generated by closing the graphite door 4 to extrude the slope pressing ring elastic pressing strip 24.

[0034] Specifically, the slope pressing ring elastic pressing strip 24 is installed on the second pressing ring 21 through the fixing bolt 17, and the slope pressing ring elastic pressing strip 24 can be made of high-elasticity CC composite material or other high-temperature-resistant and high-elasticity materials. According to the actual sintering condition of the product, two slope pressing ring elastic pressing strips 24 can be installed on each side of the second pressing ring 21, or the slope pressing ring elastic pressing strips 24 can be installed only on the left and right sides of the second pressing ring 21. The slope pressing ring elastic pressing strip 24 protrudes to the graphite door 4, that is, a pre-tightening force is generated. After the graphite door 4 is installed, the graphite door 4 extrudes the slope pressing ring elastic pressing strip 24, and the slope pressing ring elastic pressing strip 24 provides a rebound force after being deformed under stress, so that the second pressing ring 21 is extruded to press the air guide plate 15, that is, the air guide plate 15 is pre-tightened. The second pressing ring 21 has multiple parallel threaded holes, different hole positions correspond to different protrusion amounts of the slope pressing ring elastic pressing strip 24, and different protrusion amounts represent different pre-tightening forces. Therefore, the installation position can be adjusted according to the actual sintering condition of the product, that is, the pre-tightening force is adjusted, and the pre-tightening degree of the air guide plate 15 and the sealing box 3 is adjusted.

[0035] Scheme three: please refer to Figure 6.3 , the air guide plate pre-tightening structure includes a third pressing ring 30, a spring column 32 installed on the third pressing ring 30, and a third pressing ring spring 31 sleeved on the spring column 32, and a pre-tightening force is generated by closing the graphite door 4 to compress the third pressing ring spring 31; Specifically, the spring stand 32 is installed on the four corners of the third compression ring 30, and the spring stand 32 can also be installed on the third compression ring 30 according to the situation, and the third compression ring spring 31 is sleeved on the spring stand 32, and the third compression ring spring 31 is made of high-elastic CC composite material or other high-temperature-resistant and high-elastic material. When the third compression ring spring 31 is in a free state, the length is longer than the spring stand 32, the graphite door 4 is closed, the third compression ring spring 31 abuts against the graphite door 4, and a pre-tightening force is generated. After the graphite door 4 is installed, the graphite door 4 presses the third compression ring spring 31, the third compression ring spring 31 provides a rebound force after being deformed under stress, so that the third compression ring 30 is pressed to press the gas guide plate 15, that is, the gas guide plate 15 is pre-tightened. The third compression ring 30 can be installed with multiple third compression ring springs 31, so the third compression ring spring 31 can also be installed according to the actual sintering situation of the product, and the pre-tightening degree of the gas guide plate 15 and the sealing box 3 can be adjusted.

[0036] Scheme four: please refer to Figure 6.4 , the gas guide plate pre-tightening structure includes a fourth compression ring 33 and a fourth compression ring elastic sheet 35 arranged on the fourth compression ring 33 and the graphite door 4, and the fourth compression ring elastic sheet 35 arranged on the fourth compression ring 33 and the fourth compression ring elastic sheet 35 arranged on the graphite door 4 form an angle between them, and a pre-tightening force is generated by pressing the two fourth compression ring elastic sheets 35 arranged on the fourth compression ring 33 and the graphite door 4 against each other; Specifically, two fourth compression ring support rods 34 are respectively installed on the fourth compression ring 33 and the graphite door 4, and then one fourth compression ring elastic sheet 35 is respectively installed on each fourth compression ring support rod 34, and finally the two fourth compression ring elastic sheets 35 are installed vertically at 90°. After the graphite door 4 is installed, the two fourth compression ring elastic sheets 35 press against each other, and a pre-tightening force is generated. The fourth compression ring elastic sheet 35 is made of high-elastic CC composite material or other high-temperature-resistant and high-elastic material. After the graphite door 4 is installed, the two fourth compression ring elastic sheets 35 provide a rebound force after being deformed under stress, so that the fourth compression ring 33 is pressed to press the gas guide plate 15, that is, the gas guide plate 15 is pre-tightened. The length of the fourth compression ring support rod 34 can be adjusted as needed, that is, the pre-tightening degree of the gas guide plate 15 and the sealing box 3 can be adjusted.

[0037] Scheme five: please refer to Figure 6.5 , the gas guide plate pre-tightening structure includes a fifth compression ring 36, a pre-tightening shaft 37 connected with the fifth compression ring 36, and a linear drive device driving the pre-tightening shaft 37, and the compression force is dynamically adjusted by the linear drive device.

[0038] Specifically, the pre-tightening shaft 37 is installed at the center of the fifth compression ring 36, a small hole is opened in the corresponding position of the graphite door 4, the pre-tightening shaft 37 penetrates the graphite door 4, and the tail end is connected with a linear driving device such as a gas cylinder 38, which is installed outside the furnace body 1; the pre-tightening shaft 37 is in clearance fit with the graphite door 4, and the fit clearance is less than 5 silk, or a graphite fiber soft felt is used for sealing. When the device starts sintering, the material plate 20 in the sealing box 3 is heated and expanded due to high temperature, and starts to push open the gas guide plate 15. At this time, according to the temperature and expansion amount calculation, the compressed air pressure in the gas cylinder 38 is dynamically adjusted, the output force of the gas cylinder 38 is adjusted, that is, the pre-tightening force of the fifth compression ring 36 is adjusted, and the sealing property of the gas guide plate 15 and the sealing box 3 is realized.

[0039] Scheme six: please refer to Figure 6.6 , the gas guide plate pre-tightening structure includes a fourth compression ring 33, a fourth compression ring elastic sheet 35 connected with the fourth compression ring 33, a pre-tightening shaft 37 connected with the fourth compression ring elastic sheet 35, and a linear driving device driving the pre-tightening shaft 37, and the compression force is dynamically adjusted by the linear driving device.

[0040] Specifically, the pre-tightening shaft 37 is installed on the extension rod of a linear driving device such as an electric cylinder 39, a small hole is opened in the corresponding position of the graphite door 4, the pre-tightening shaft 37 penetrates the graphite door 4 and contacts the fourth compression ring elastic sheet 35, the fourth compression ring elastic sheet 35 is installed on the fourth compression ring 33 through the fourth compression ring support rod 34, and the electric cylinder 39 is installed outside the furnace body 1; the pre-tightening shaft 37 is in clearance fit with the graphite door 4, and the fit clearance is less than 5 silk, or a graphite fiber soft felt is used for sealing. When the device starts sintering, the material plate 20 in the sealing box 3 is heated and expanded due to high temperature, and starts to push open the gas guide plate 15. At this time, according to the temperature and expansion amount calculation, the extension size of the electric cylinder 39 is dynamically adjusted, which acts on the fourth compression ring elastic sheet 35, the fourth compression ring elastic sheet 35 is deformed under stress, providing a rebound force, which acts on the fourth compression ring 33. Therefore, the larger the extension size of the electric cylinder 39, the greater the force acting on the fourth compression ring 33, that is, adjusting the extension size of the electric cylinder 39 adjusts the pre-tightening force of the fourth compression ring 33, and the sealing property of the gas guide plate 15 and the sealing box 3 is realized.

[0041] On the basis of successfully constructing the above-mentioned controllable atmosphere introduction channel, in order to further deal with the pollution risk possibly introduced by the accidental opening of the safety valve, a passive protection and flow guide subsystem, that is, a baffle system, is arranged in the sealing box sintering area.

[0042] In the subsystem, the material plate 20 for carrying the sintered workpiece in the sintering area of the sealed box is placed on the predetermined boss of the left plate and the right plate of the sealed box. The upper baffle 13 is arranged between the upper plate 3.1 of the sealed box and the uppermost material plate 20, and the lower baffle 14 is arranged between the lower plate 3.2 of the sealed box and the lowermost material plate 20, and the lower baffle 14 can also be used as a material plate for carrying materials. The side edges of the upper baffle 13 and the lower baffle 14 are in contact with the inner side of the corresponding end of the air guide plate 15, respectively.

[0043] Preferably, the sintering area of the sealed box is divided into two front and rear areas, and each area is provided with a corresponding upper baffle 13 and lower baffle 14. The upper baffles 13 in the two areas are connected by elastic members 22, and the lower baffles 14 in the two areas are also connected by elastic members 22. The elastic restoring force provided by the elastic members 22 not only makes the side edges of the baffles close to the air guide plates 15, but also automatically compensates for the size change and stress caused by the different thermal expansion coefficients of the material plates 20, the sealed box body and other components during high-temperature sintering, thereby realizing dynamic sealing.

[0044] The elastic member 22 can be an elastic sheet 28 as shown in Figure 7.1 , a spring 27 as shown in Figure 7.2 , or as shown in Figure 7.3 , the upper baffles 13 arranged opposite to each other, the upper baffle 13 on one side is fixed with a support rod 29 for mounting both ends of the elastic sheet 28, and the upper baffle 13 on the other side is fixed with a support rod 29 for abutting against the middle part of the elastic sheet 28. The same applies to the lower baffles 14.

[0045] The material plates 20 are arranged in the front and rear areas, respectively, and there is a gap between the front and rear areas. The lower plate 3.2 of the sealed box 3 is provided with a dewaxing pipe 7 communicating with the outside at the gap, for discharging gas.

[0046] The first cavity 25 is formed between the upper baffle 13 and the upper plate 3.1 of the sealed box, and the second cavity 26 is formed between the lower baffle 14 and the lower plate 3.2 of the sealed box. The upper safety valve 12 is arranged on the upper plate 3.1 of the sealed box and communicates with the first cavity 25, and the lower safety valve is arranged on the lower plate 3.2 of the sealed box and communicates with the second cavity 26.

[0047] When the upper safety valve 12 is opened due to excessive external pressure or too fast internal vacuum, the gas from the external environment (which may contain impurities and water vapor separated from the insulation material, etc.) rushes in, first entering the first cavity 25. Since the upper baffle 13 is tightly attached to the air guide plate 15 on the side under the action of the elastic member 22, and the air guide plate 15 itself is sealed with the box, this contaminated gas cannot penetrate downward into the core product sintering space, but can only move along the first cavity 25 between the sealed box upper plate 3.1 and the upper baffle 13 to the middle of the sealed box 3, and then be directly removed from the dewaxing pipe 7, without flowing through the product, thereby preventing the product from being contaminated.

[0048] Similarly, when the lower safety valve is opened, the contaminated gas is confined in the second cavity 26 and is directed horizontally to the central dewaxing pipe 7 for discharge, effectively preventing the upward flow of pollutants to contaminate the workpiece.

[0049] To further optimize the protection effect of the lower safety valve, in a preferred embodiment, the lower safety valve is differentially set. The lower safety valve includes at least one first lower safety valve 10 and at least one second lower safety valve 11, the opening pressure of the first lower safety valve 10 is less than that of the second lower safety valve 11, and the first lower safety valve 10 is closer to the dewaxing pipe 7 in the horizontal direction than the second lower safety valve 11.

[0050] When there is a small pressure difference between the inside and outside of the sealed box 3, the first lower safety valve 10 will open first. Since it is closer to the discharge port, the contaminated gas that rushes in can enter the central flow passage of the second cavity 26 in a shorter and more direct path and be quickly discharged to the dewaxing pipe 7, thereby minimizing the diffusion range and residence time of the pollutants in the bottom of the box, and further improving the protection efficiency. Since the lower safety valve opens more frequently than the upper one, only the lower part is provided with double safety valves.

[0051] In summary, the present embodiment establishes a first level of isolation inside the sealed box through the air guide plate and its pre-tightening structure, ensuring that the process gas can only enter the sintering area uniformly through the designed path. Through the cooperation of the upper and lower baffles with the safety valves and cavities, a second level of protection is established, which guides and concentrates the contaminated gas introduced by the opening of the safety valve to avoid its contact with the workpiece. The two-stage structure works together to significantly improve the purity and stability of the atmosphere in the sintering area, thereby improving the consistency and reliability of the product sintering quality.

[0052] In the description of the present application, it needs to be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used for the convenience of describing the present application, and do not imply or require that the devices or elements referred to must have a particular orientation or configuration, and therefore should not be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description objects and should not be understood as limiting the importance or order, and such terms limited features can be explicitly or implicitly included one or more features. Unless otherwise stated, "a plurality" in the description of the present application means two or more.

[0053] For the terms "mounting", "connecting", "connecting", unless otherwise explicitly limited, should be broadly understood, including but not limited to fixed connection, detachable connection or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through intermediate medium; and the communication between two elements. Those skilled in the art can understand its meaning according to the specific technical solution. In the present application, the fixed connection involved, unless otherwise stated, includes detachable fixed connection (such as bolt, screw connection), and also includes non-detachable fixed connection (such as riveting, welding), and also includes the whole structure realized by integral molding process (except for obvious integral molding).

[0054] The terms used to represent the positional relationship or shape in any technical solution disclosed in the present application, unless otherwise stated, cover the approximate, similar or close state or shape.

[0055] Any component provided by the present application can be assembled by a plurality of separate components, or can be a separate component manufactured by integral molding process.

[0056] It should be understood that the structure, proportion, size and the like shown in the drawings of the present application are only used to cooperate with the content disclosed in the specification, so that those skilled in the art can understand and read, and are not used to limit the limiting conditions of the implementation of the present application, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0057] The same reference signs in the embodiments of the present application represent the same component or the same part.

[0058] Any adaptive change according to actual needs is within the scope of protection of the present application.

[0059] It is to be understood that the application is not limited to the details of the above-exemplified embodiment and can be practiced with alteration and in various other specific forms without departing from the spirit or essential characteristics of the application. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No feature of the application is considered critical unless it is expressly stated in the claims.

Claims

1. A sinter zone isolation system for a vacuum debinding sintering furnace, characterized by: The sealing box (3) is provided with a gas guide plate (15) inside the graphite door (4), and the periphery of the gas guide plate (15) is in sealing connection with the inner wall of the sealing box (3), so that the area inside the graphite door (4) is divided into an air inlet diffusion area close to the graphite door and a sealing box sintering area close to the inside of the sealing box (3); the gas guide plate (15) is provided with a gas guide hole for directing and quantifying the flow of gas from the air inlet diffusion area to the sealing box sintering area; the gas guide plate (15) is also connected with a gas guide plate pre-tightening structure for providing a pre-tightening force to the periphery of the gas guide plate (15) to press the inner wall of the sealing box (3).

2. The sintering zone isolation system of a vacuum debinding sintering furnace of claim 1, characterized in that: The inner wall of the sealing box (3) is provided with a surrounding sealing step, and the periphery of the gas guide plate (15) abuts on the sealing step to realize face sealing; the gas guide plate pre-tightening structure includes a pressing structure pressing the outer periphery of the gas guide plate (15) and an elastic force element providing a pressing force to the pressing structure.

3. The sintering zone isolation system of a vacuum debinding sintering furnace of claim 2, wherein: The sealing step is arranged on the sealing box upper plate (3.1), the sealing box lower plate (3.2), the sealing box left plate and the sealing box right plate of the sealing box (3); the gas guide plate (15) at the rear end of the sealing box (3) is directly fixed on the sealing step through a locking piece penetrating through the pressing structure, and the gas guide plate (15) at the front end of the sealing box (3) is pre-tightened through the gas guide plate pre-tightening structure and the graphite door (4).

4. The sintering zone isolation system of a vacuum debinding sintering furnace according to claim 3, characterized in that: The gas guide plate pre-tightening structure is any one of the following: Scheme one: including a first pressing ring (16), an elastic pressing strip (18) fixed on the first pressing ring (16), and a pre-tightening bolt (19) installed on the graphite door (4), the pre-tightening force is generated by pressing the elastic pressing strip (18) through the pre-tightening bolt (19); Scheme two: including a second pressing ring (21) with an inclined surface and an inclined pressing ring elastic pressing strip (24) fixed on the second pressing ring (21), the pre-tightening force is generated by pressing the inclined pressing ring elastic pressing strip (24) by closing the graphite door (4); Scheme three: including a third pressing ring (30), a spring column (32) installed on the third pressing ring (30), and a third pressing ring spring (31) sleeved on the spring column (32), the pre-tightening force is generated by compressing the third pressing ring spring (31) by closing the graphite door (4); Scheme four: including a fourth pressing ring (33) and a fourth pressing ring elastic sheet (35) arranged on the fourth pressing ring (33) and the graphite door (4), the fourth pressing ring elastic sheet (35) arranged on the fourth pressing ring (33) and the fourth pressing ring elastic sheet (35) arranged on the graphite door (4) form an angle, the pre-tightening force is generated by pressing the two fourth pressing ring elastic sheets (35) arranged on the fourth pressing ring (33) and the graphite door (4) against each other. Scheme five: comprising a fifth pressing ring (36), a pre-tightening shaft (37) connected with the fifth pressing ring (36), and a linear driving device driving the pre-tightening shaft (37), and the pressing force is dynamically adjusted by the linear driving device; Scheme six: comprising a fourth pressing ring (33), a fourth pressing ring elastic sheet (35) connected with the fourth pressing ring (33), a pre-tightening shaft (37) connected with the fourth pressing ring elastic sheet (35), and a linear driving device driving the pre-tightening shaft (37), and the pressing force is dynamically adjusted by the linear driving device.

5. The sintering zone isolation system of a vacuum debinding sintering furnace of claim 4, wherein: In scheme five and scheme six, the pre-tightening shaft (37) passes through the corresponding hole on the graphite door (4) and is connected with the output end of the linear driving device; the linear driving device is installed outside the furnace body (1).

6. The sintering zone isolation system of a vacuum debinding sintering furnace according to any one of claims 3 to 5, characterized in that: The sealing box sintering area is provided with a material plate (20) for carrying workpieces, an upper baffle (13) is arranged between the sealing box upper plate (3.1) and the uppermost material plate (20), and a lower baffle (14) is arranged between the sealing box lower plate (3.2) and the lowermost material plate (20); the side edges of the upper baffle (13) and the lower baffle (14) are in contact with the corresponding end of the gas guide plate (15).

7. The sintering zone isolation system of a vacuum debinding sintering furnace of claim 6, characterized in that: The sealing box sintering area is divided into front and rear areas, each area is provided with a corresponding upper baffle (13) and lower baffle (14), the upper baffles (13) in the two areas are connected by elastic members (22), and the lower baffles (14) in the two areas are also connected by elastic members (22); the elastic members (22) can drive the side edges of the upper baffles (13) or lower baffles (14) to always press the corresponding gas guide plates (15).

8. The sintering zone isolation system of a vacuum debinding sintering furnace according to claim 7, characterized in that: The front and rear areas are respectively provided with the material plates (20), and the sealing box (3) has a gap between the front and rear areas; the lower plate (3.2) of the sealing box (3) is provided with a dewaxing pipe (7) corresponding to the gap, for discharging gas.

9. The sintering zone isolation system of a vacuum debinding sintering furnace according to claim 8, characterized in that: A first cavity (25) is formed between the upper baffle (13) and the sealing box upper plate (3.1), and a second cavity (26) is formed between the lower baffle (14) and the sealing box lower plate (3.2); the sealing box upper plate (3.1) is provided with an upper safety valve (12) communicating with the first cavity (25), and the sealing box lower plate (3.2) is provided with at least one lower safety valve (10, 11) communicating with the second cavity (26).

10. The sintering zone isolation system of a vacuum debinding sintering furnace of claim 9, wherein: The lower safety valve includes at least one first lower safety valve (10) and at least one second lower safety valve (11), the opening pressure of the first lower safety valve (10) is less than that of the second lower safety valve (11), and the first lower safety valve (10) is closer to the dewaxing pipe (7) in the horizontal direction than the second lower safety valve (11).

Images