Multi-atmosphere controllable alloy powder sintering furnace

Abstract

The invention discloses a multi-atmosphere controllable alloy powder sintering furnace, belongs to the technical field of sintering furnaces, and aims to carry out partitioned multi-atmosphere independent control on the basis of a traditional sintering furnace, realize switching of various protective atmospheres among different furnace regions and meet strict requirements of various complex alloy materials on a sintering environment. A temperature field and atmosphere distribution of a high-temperature area are optimized and improved, an inert atmosphere conveying assembly jointly acting on a preheating area and the high-temperature area is adopted, the temperature difference between inert atmosphere and the interior of a high-temperature area furnace is reduced in a multi-stage preheating mode, and flow field optimization structures for directionally conveying reducing atmosphere are arranged on the left inner wall and the right inner wall of a furnace body of the high-temperature area. The descending reducing atmosphere is distributed and optimized, the reducing atmosphere is promoted to diffuse towards the middle of the furnace chamber to impact the inert atmosphere, a boundary layer is effectively broken, atmosphere layering is prevented, a complementary double-atmosphere system is formed, and flowing and distribution of the atmosphere in the furnace are perfectly optimized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sintering furnace, more particularly, to a multi-atmosphere controllable alloy powder sintering furnace. BACKGROUND

[0002] Alloy powder sintering is usually used for manufacturing high-performance materials such as cemented carbide, metal matrix composites, etc., based on powder metallurgy technology, which is a method of converting metal powder into solid and high-precision alloy materials through steps such as mixing, pressing and sintering.

[0003] In common metallurgical plants, a mesh belt sintering furnace is usually used to sinter and form the metal powder filled in the mold, which includes a conveyor belt composed of chain plates and a furnace body for sintering. For details, please refer to the main content of patent numbers CN213932011U and CN219121042U.

[0004] The existing sintering furnace (single-atmosphere or fixed-atmosphere furnace type) cannot control multiple zones independently, and different atmosphere environments and the atmosphere distribution in the independent atmosphere environment will affect the sintering process and effect. In addition, the existing ordinary metal sintering furnace uses fixed gas supply holes for gas supply, and the gas flow direction of the fixed holes is single, which cannot form an effective directional flow field and is difficult to cover the entire cross section of the furnace cavity, which will cause the atmosphere concentration, flow rate and temperature at different positions in the furnace to have a gradient.

[0005] Therefore, in view of the existing actual production problems, a multi-atmosphere controllable alloy powder sintering furnace is proposed. SUMMARY

[0006] The present application aims to solve the existing problems and provides a multi-atmosphere controllable alloy powder sintering furnace compared with the prior art.

[0007] The purpose of the present application can be achieved by the following technical solution: a multi-atmosphere controllable alloy powder sintering furnace, comprising a conveying outer box and a furnace body embedded and installed inside and outwardly penetrating from top to bottom, the furnace body and the conveying outer box form a furnace cavity with open ends, a mesh belt conveyor extending outward from both ends is installed on the inner side of the furnace cavity;

[0008] The left and right ends of the furnace cavity are provided with an isolation layer arranged at one end of the mesh belt conveyor, and a pair of isolation layers divide the internal space of the furnace cavity into a preheating zone, a high-temperature zone and a cooling zone. The end parts of the preheating zone and the cooling zone are provided with sealing doors matched with the mesh belt conveyor, the top of the preheating zone is embedded and installed with an atmosphere preheating assembly, and the top of the high-temperature zone is installed with a plurality of heat radiation pipes and an inert atmosphere conveying assembly.

[0009] The inert atmosphere conveying assembly comprises a plurality of heat exchange pipes penetrating through the atmosphere preheating assembly, and a U-shaped communication box installed between a pair of isolation layers is communicated with conveying ends of the heat exchange pipes.

[0010] The high-temperature zone further comprises a flow field optimization structure outside the arc-shaped flow distribution plate and a reducing atmosphere conveying structure acting on the flow field optimization structure.

[0011] Further, the isolation layer is a disc-shaped structure matching the internal structure of the furnace cavity, and a gas curtain groove adapted to the mesh belt conveyor is formed at the lower end of the isolation layer.

[0012] Further, the atmosphere preheating assembly comprises a preheating box embedded and installed at the top of the furnace cavity, a heating coil horizontally arranged is installed at the inner side of the preheating box, an air inlet pipe one is connected to the top end of the preheating box, and a pair of preheating air distribution plates in an arc-shaped structure are fixedly communicated at the lower end of the preheating box.

[0013] Further, an upward backflow space is reserved between the preheating air distribution plate and the inner wall of the furnace body, and backflow guide plates extending to the top of the upward backflow space are fixedly connected at the two sides of the upper end of the preheating box.

[0014] Further, the heat exchange pipes are in a U-shaped structure and are staggered with the heat radiation pipes, the two free ends of the heat exchange pipes are arranged towards the preheating zone, an extension is connected to one of the free ends of the heat exchange pipes, the extension penetrates through the lower end of the preheating box and extends to the outside of the top of the conveying outer box, the other free ends of the heat exchange pipes are connected to the U-shaped communication box as conveying ends, the U-shaped communication box is also in a U-shaped structure and is arranged with an opening towards the cooling zone, and a communication cavity is formed in the U-shaped communication box and is communicated with the arc-shaped flow distribution plate and the heat exchange pipes.

[0015] Further, the reducing atmosphere conveying structure comprises a plurality of air inlet pipes embedded and installed at the top of a plurality of arc-shaped cyclone grooves arranged left and right, the upper ends of the air inlet pipes extend outward and are jointly connected to a gas supply pipe, and gas supply nozzles are connected to the lower ends of the air inlet pipes.

[0016] Further, the pair of arc-shaped distribution plates are arc-shaped structures concentrically arranged with the furnace body, the plurality of guide plates are annularly distributed in the arc-shaped cyclone groove and the outer ends are one-to-one connected to the inner sides of the lower ends of the corresponding distribution grooves, and the guide plates are convex structures, one end of the guide plate inside the arc-shaped cyclone groove is provided with a rounded corner, and the left and right two guide plates are arranged adjacent to the outer side of the arc-shaped cyclone groove.

[0017] Further, the guide plate and the inner end wall of the arc-shaped cyclone groove are reserved with a flow field downward passage, and the width of the plurality of flow field downward passages distributed along the annular direction of the arc-shaped cyclone groove decreases from top to bottom.

[0018] Further, the cooling zone top is embedded with a cooling assembly, which includes a cooling box embedded and installed on the cooling zone top and externally connected with the second air inlet pipe, the lower end of the cooling box is fixedly connected with heat exchange vent plates which are also arc-shaped structures, and a plurality of heat exchange holes are distributed on the opposite end walls of the pair of heat exchange vent plates.

[0019] Compared with the prior art, the advantages of the present application are:

[0020] 1. The present application is based on the traditional sintering furnace for partitioning and independently controlling multiple atmospheres, achieving switching of multiple protective atmospheres between different furnace zones to meet the harsh requirements of various complex alloy materials on the sintering environment. In addition, the temperature field and atmosphere distribution in the high-temperature zone are optimized and improved, the inert atmosphere delivery assembly acting on the preheating zone and the high-temperature zone is adopted to realize the multi-stage preheating mode to reduce the temperature difference between the inert atmosphere and the high-temperature zone, and the flow field optimization structure for directional delivery of the reducing atmosphere is arranged on the left and right inner walls of the high-temperature zone furnace body. The reducing atmosphere diffuses towards the middle of the furnace cavity under the action of pressure, impacting the inert atmosphere, forming a complementary "double atmosphere system", and perfectly optimizing the atmosphere flow and distribution in the furnace.

[0021] 2. Based on the above, the flow field optimization structure is designed with a spatially decreasing width from top to bottom, specifically, the guide plate and the inner end wall of the arc-shaped cyclone groove are reserved with a flow field downward passage, the width of the plurality of flow field downward passages decreases from top to bottom, the reducing atmosphere enters the arc-shaped cyclone groove for distribution and optimization, and in the downward process, the reducing atmosphere is divided by the plurality of guide plates towards the arc-shaped distribution plate, the gradually changing flow space divides and guides the reducing atmosphere, and the purpose is to make the two gas flows meet in the middle of the high-temperature zone, the reducing gas flow impacts and agitates the inert gas flow, effectively breaking the boundary layer and preventing atmosphere stratification, greatly optimizing the flow pattern and uniformity of the atmosphere in the furnace, and ensuring that the reducing atmosphere can fully wrap the workpiece. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is an external structure diagram of the present application;

[0023] Figure 2Fig. 1 is a schematic view of the structure of the combination of the transfer outer box, the furnace body and the isolation layer of the present application;

[0024] Figure 3 Fig. 2 is a schematic view of the structure of the input end of the present application;

[0025] Figure 4 Fig. 3 is a sectional view of the input end of the present application during preheating operation;

[0026] Figure 5 Fig. 4 is an end sectional view of the high temperature zone of the present application; Figure 1 ;

[0027] Figure 6 Fig. 5 is a schematic view of the structure of the combination of the atmosphere preheating assembly and the inert atmosphere delivery assembly of the present application;

[0028] Figure 7 Fig. 6 is an end sectional view of the combination of the furnace body and the flow field optimization structure and the reducing atmosphere delivery structure of the present application;

[0029] Figure 8 Fig. 7 is an end sectional view of the high temperature zone of the present application; Figure 2 ;

[0030] Figure 9 Fig. 8 is a schematic view of the annular groove combustion structure of the present application for the high temperature zone;

[0031] Figure 10 Fig. 9 is a schematic view of the structure of the output end of the present application.

[0032] Fig. 10 is a legend of the figures.

[0033] 1, transfer outer box; 2, furnace body; 201, arc-shaped cyclone groove; 3, mesh belt conveyor; 4, isolation layer; 5, preheating box; 501, air inlet pipe 1; 502, backflow guide plate; 6, preheating air baffle; 7, heat exchange pipe; 8, U-shaped communication box; 9, arc-shaped flow dividing plate; 901, flow dividing groove; 10, flow guide plate; 11, air inlet pipe; 12, air supply pipe; 13, air supply nozzle; 14, cooling box; 141, air inlet pipe 2; 15, heat exchange air baffle; 16, heat radiation pipe. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0035] Embodiment one: for the traditional single atmosphere or fixed atmosphere furnace, unable to carry out multi-zone independent atmosphere control, and fixed type gas supply mode cannot form effective directional atmosphere flow field problem, present the following technical scheme:

[0036] The application discloses a multi-atmosphere controllable alloy powder sintering furnace, please refer to Figures 1-2 , including conveying outer box 1 and embedded installation in its inside and up and down outwardly penetrating furnace body 2, the furnace body 2 is cylindrical structure, the conveying outer box is rectangular structure, the furnace body 2 and the conveying outer box 1 enclose the furnace cavity with both ends open, the inside bottom of the furnace cavity is installed with the net belt conveyor 3 extending outward at both ends;

[0037] The left and right ends of the furnace cavity are provided with an isolation layer 4 arranged at one end of the net belt conveyor 3, and the pair of isolation layers 4 separate the inside of the furnace cavity into a preheating zone, a high-temperature zone and a cooling zone; the preheating zone and the cooling zone are each provided with a sealing door matched with the net belt conveyor 3.

[0038] The isolation layer 4 is a disc-shaped structure matched with the internal structure of the furnace cavity, and the lower end of the isolation layer 4 is provided with an air curtain groove matched with the net belt conveyor 3; the top of the air curtain groove is directly connected to the top of the isolation layer 4, and the top of the air curtain groove is provided with an inert atmosphere inlet; the physical baffle and the air curtain (N2 curtain) are matched to ensure the atmosphere isolation of each zone.

[0039] Please refer to Figures 3-4 , the top of the preheating zone is embedded with an atmosphere preheating assembly, which comprises a preheating box 5 embedded and installed on the top inside of the conveying outer box 1 and located at the top inside of the furnace body 2; the inside middle of the preheating box 5 is provided with horizontally arranged heating coils; the top end of the preheating box 5 is externally connected with an air inlet pipe one 501; and the lower end of the preheating box 5 is fixedly connected with arc-shaped preheating air inlet plates 6 on both sides.

[0040] A plurality of shunt holes are distributed on the opposite end walls of the pair of preheating air inlet plates 6, and an upward return flow space is reserved between the preheating air inlet plates 6 and the inner wall of the furnace body 2; the upper sides of the preheating box 5 are fixedly connected with return guide plates 502 extending to the top of the upward return flow space; the preheating atmosphere such as nitrogen is introduced into the inside of the preheating box 5 through the air inlet pipe one 501; the preheated nitrogen is uniformly diffused to the preheating zone through the pair of preheating air inlet plates 6; on the one hand, the preheating atmosphere effectively preheats the alloy powder compact conveyed to the preheating zone; and on the other hand, the preheating atmosphere safely and effectively removes the binder to realize degreasing.

[0041] Please refer to Figures 5-9 , a plurality of heat radiation pipes 16 and inert atmosphere conveying assemblies located below the heat radiation pipes 16 are installed at the top inside of the high-temperature zone; the inert atmosphere conveying assemblies comprise a plurality of heat exchange pipes 7 penetratingly arranged with the atmosphere preheating assembly; the conveying end of the heat exchange pipe 7 is connected with a U-shaped communication box 8 installed between the pair of isolation layers 4; and the left and right ends of the U-shaped communication box 8 are fixedly connected with arc-shaped shunt plates 9 for uniform conveying of the atmosphere.

[0042] The heat exchange pipe 7 is in a U-shaped structure and is staggered with the heat radiation pipe 16 left and right, and the two free ends of the heat exchange pipe 7 are arranged towards the preheating area, and an extension section is arranged outside one of the free ends of the heat exchange pipe 7, the extension section penetrates through the lower end of the preheating box 5 and extends to the outside of the top of the conveying outer box 1, and the other free end of the plurality of heat exchange pipes 7 is connected with the U-shaped communication box 8 as a conveying end, and the U-shaped communication box 8 is also in a U-shaped structure and is arranged with an opening towards the cooling area;

[0043] The U-shaped communication box 8 is internally provided with a communication cavity in communication with the arc-shaped flow dividing plate 9 and the heat exchange pipe 7, and the pair of arc-shaped flow dividing plates 9 are in an arc-shaped structure concentrically arranged with the furnace body 2, the inert atmosphere is supplied through the extension section of the heat exchange pipe 7, the inert atmosphere is firstly preheated by the heating box 5, and then is combined with the high-temperature heating of the heat radiation pipe 16 after being introduced into the high-temperature area, so that two-stage heating is realized, the inert atmosphere conveying assembly acting on the preheating area and the high-temperature area is adopted, the inert atmosphere and the high-temperature area furnace temperature difference is reduced in a multi-stage preheating mode, and the preheated inert atmosphere is uniformly diffused from the side to the middle of the high-temperature area furnace cavity through the pair of arc-shaped flow dividing plates 9.

[0044] The inner walls on both sides of the high-temperature area are further provided with a flow field optimization structure located outside the arc-shaped flow dividing plate 9 and a reducing atmosphere conveying structure acting on the flow field optimization structure, and the reducing atmosphere conveying structure comprises a gas inlet pipe 11 embedded and installed on the top of a plurality of arc-shaped cyclone grooves 201 arranged left and right, the upper end of the gas inlet pipe 11 extends outward and is jointly connected with a gas supply pipe 12, and the lower end of the gas inlet pipe 11 is connected with a gas supply nozzle 13;

[0045] The flow field optimization structure comprises an arc-shaped cyclone groove 201 provided on the inner walls of the furnace body 2 left and right, a plurality of guide plates 10 corresponding in position to the arc-shaped flow dividing plate 9 and extending to the inner side of the arc-shaped flow dividing plate 9 are embedded and installed on the arc-shaped cyclone groove 201, and a plurality of flow dividing grooves 901 corresponding in position to the guide plates 10 are provided on the end wall of the arc-shaped flow dividing plate 9;

[0046] The reducing atmosphere, such as preheated reducing hydrogen, is delivered to the inside of the plurality of arc-shaped cyclone grooves 201 through the gas inlet pipe 11, and is injected in a wide range by the gas supply nozzle 13. The reducing atmosphere moves downward along the top of the arc-shaped cyclone groove 201, and during the downward movement in the annular direction, the reducing atmosphere is intercepted and guided by the plurality of guide plates 10, and the direction of the reducing atmosphere is changed. The reducing atmosphere is "cut" by the guide plates 10 and is impacted and stirred in the middle of the furnace body, so as to optimize the flow pattern of the atmosphere in the furnace and enhance the reducing property, and form a complementary "double atmosphere system". The reducing atmosphere is gathered to the middle of the furnace cavity through the shunt groove 901, and a horizontal cyclone high-temperature zone (1200-1400C) is formed. The double gas path design forces the atmosphere in the furnace to form convection and cyclone, optimizes the flow pattern of the inert atmosphere, avoids dead angles, and makes the temperature and concentration distribution more uniform. In addition, the preheated reducing atmosphere itself carries heat energy, and the diffusion and injection of the reducing atmosphere help to compensate for the heat loss near the furnace wall, so that the transverse temperature in the furnace is more uniform.

[0047] It should be noted that the root of the guide plate 10 will bear the erosion of the high-speed atmosphere, and the guide plate 10 is made of Hastelloy C-276, and a plasma sprayed zirconia coating is formed on the surface of the guide plate 10.

[0048] Please refer to Figure 10 The cooling assembly is embedded and installed on the top of the cooling zone and includes a cooling box 14 which is embedded and installed on the top of the cooling zone and is connected with the gas inlet pipe two 141. The gas inlet pipe two 141 is used to deliver the inert atmosphere, such as inert gas, to prevent the product from being oxidized during the cooling process.

[0049] The cooling box 14 is fixedly connected with the heat exchange vent plates 15 which are also arc-shaped structures on both sides of the lower end of the cooling box 14. A plurality of heat exchange holes are distributed on the opposite end walls of the pair of heat exchange vent plates 15. The cooling assembly and the atmosphere preheating assembly are similar in structure, that is, one is a heating box and the other is a cooling box. The inside of the heat exchange vent plate 15 is provided with a semiconductor refrigeration structure, and the cooling temperature of the semiconductor refrigeration structure for cooling the inert atmosphere is determined according to the product.

[0050] Example two: on the basis of example one, the flow field optimization structure is further supplemented and described as follows:

[0051] Please refer to Figures 7-9 The plurality of guide plates 10 are annularly distributed in the arc-shaped cyclone groove 201 and are connected to the inner sides of the lower ends of the corresponding shunt grooves 901 at the outer ends. The guide plates 10 are convex structures, and the left and right guide plates 10 are arranged adjacent to each other at the portions outside the arc-shaped cyclone groove 201.

[0052] On the one hand, the contact area between the guide plate 10 and the furnace body 2 is increased, and the installation strength of the guide plate 10 is improved. On the other hand, the horizontally arranged multiple guide plates 10 form an atmosphere conveying guide wall, which facilitates the reduction atmosphere flowing into the arc-shaped diversion groove 901 of the arc-shaped diversion plate 9 from the inside of the arc-shaped rotational flow groove 201, and the reduction atmosphere diffuses to the middle of the high-temperature zone furnace cavity through the diversion groove 901. The design of the guide plate 10 can control the flow and strengthen the groove structure, effectively solving the problem of thermal stress of the groove structure at high temperature.

[0053] The guide plate 10 is provided with a rounded corner at one end inside the arc-shaped rotational flow groove 201 to reduce the impact of the reduction atmosphere on the guide plate 10.

[0054] The guide plate 10 and the inner end wall of the arc-shaped rotational flow groove 201 are reserved with flow field downward passages, and the width of the multiple flow field downward passages distributed along the annular direction of the arc-shaped rotational flow groove 201 decreases from top to bottom. The reduction atmosphere enters the arc-shaped rotational flow groove 201, flows downward through the multiple flow field downward passages, and is diverted by the multiple guide plates 10 toward the arc-shaped diversion plate 9 during the downward process. The gradually changing flow space realizes "automatic grading of reduction atmosphere", and the smaller the reduction atmosphere flux is, the more downward it is. The space-decreasing flow structure realizes intelligent distribution of the reduction atmosphere. The purpose is to uniformly guide most of the reduction atmosphere to the middle of the furnace cavity, and to form impact and agitation of the reduction gas flow on the inert gas flow, effectively breaking the boundary layer and preventing atmosphere stratification, greatly optimizing the flow pattern and uniformity of the furnace atmosphere, and ensuring that the reducing atmosphere can fully wrap the workpiece. The second is to reduce the bottom heat flux protection net belt, and perfectly balance the dual needs of middle high-temperature heating and net belt heat protection.

[0055] In addition, it is also necessary to supplement that the arc-shaped rotational flow groove 201 opened on both sides is connected with the bottom of the furnace body 2, and multiple flow passages are opened in the bottom of the conveying outer box 1 to realize the downward flow of a small amount of reduction atmosphere, maintain the weak convection (<600℃) protection net belt, and avoid insufficient heat convection caused by insufficient reduction atmosphere at the bottom of the net belt conveyor 3.

[0056] In summary: based on the traditional sintering furnace, the partitioned multi-atmosphere independent control is carried out to realize the switching of multiple protection atmospheres between different furnace zones, meet the harsh requirements of various complex alloy materials on sintering environment, in addition, the temperature field and atmosphere distribution of the high-temperature zone are optimized and improved, the inert atmosphere conveying assembly acting on the preheating zone and the high-temperature zone is adopted to realize the multi-stage preheating mode to reduce the temperature difference between the inert atmosphere and the high-temperature zone furnace;

[0057] And in the high temperature zone of the furnace body left and right inner wall set for the reducing atmosphere directional delivery flow field optimization structure, reducing atmosphere under the action of pressure, diffusion to the middle of the cavity impact inert atmosphere, effectively break the boundary layer, prevent the atmosphere stratification, form a complementary "double atmosphere system", perfect optimization of the atmosphere flow and distribution in the furnace, greatly optimized the flow pattern and uniformity of the atmosphere in the furnace, on the one hand, the use of reducing atmosphere (hydrogen) purification surface of workpiece, on the other hand, the use of reducing atmosphere kinetic energy optimization inert protective atmosphere (nitrogen) flow field, solve the problem of uneven distribution of traditional sintering furnace atmosphere.

[0058] The above description is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacement or change according to the technical solution and the improvement concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A multi-atmosphere controllable alloy powder sintering furnace, comprising a conveying outer box (1) and a furnace body (2) embeddedly installed inside and outwardly penetrating up and down, the furnace body (2) and the conveying outer box (1) form a furnace cavity with open ends, a mesh belt conveyor (3) extending outward at both ends is installed on the inside bottom of the furnace cavity, characterized in that: a pair of isolation layers (4) are arranged at both ends of the furnace cavity and are arranged at one end of the mesh belt conveyor (3), a pair of isolation layers (4) divide the inside of the furnace cavity into a preheating zone, a high-temperature zone and a cooling zone, an atmosphere preheating assembly is embeddedly installed on the top of the preheating zone, a plurality of heat radiation pipes (16) and an inert atmosphere conveying assembly are installed on the top of the high-temperature zone, the inert atmosphere conveying assembly comprises a plurality of heat exchange pipes (7) penetrating through the atmosphere preheating assembly, the conveying end of the heat exchange pipe (7) is communicated with a U-shaped communication box (8) installed between the pair of isolation layers (4), and the left and right ends of the U-shaped communication box (8) are fixedly connected with arc-shaped shunt plates (9) for uniform atmosphere conveying. The two side walls of the high-temperature zone are further provided with a flow field optimization structure outside the arc-shaped shunt plate (9) and a reducing atmosphere conveying structure acting on the flow field optimization structure, wherein the flow field optimization structure comprises arc-shaped cyclone grooves (201) opened on the left and right inner walls of the furnace body (2), a plurality of guide plates (10) corresponding to the positions of the arc-shaped shunt plates (9) are embeddedly installed on the arc-shaped cyclone grooves (201), and a plurality of shunt grooves (901) are opened on the end wall of the arc-shaped shunt plate (9) and are opposite to the outer ends of the guide plates (10).

2. The multi-atmosphere controllable alloy powder sintering furnace according to claim 1, characterized in that: The isolation layer (4) is a disc structure matching the internal structure of the furnace cavity, and a gas curtain groove adapted to the mesh belt conveyor (3) is opened at the lower end of the isolation layer (4), the gas curtain groove is directly connected to the top of the isolation layer (4), and an inert atmosphere inlet is arranged on the top of the gas curtain groove.

3. The multi-atmosphere controllable alloy powder sintering furnace according to claim 1, characterized in that: The atmosphere preheating assembly comprises a preheating box (5) embeddedly installed on the top of the furnace cavity, a heating coil horizontally arranged is installed on the inside middle of the preheating box (5), an air inlet pipe one (501) is connected to the top end of the preheating box (5), arc-shaped preheating air inlet plates (6) are fixedly and communicatively connected to the lower sides of the preheating box (5), and a plurality of shunt holes are distributed on the opposite end walls of the pair of preheating air inlet plates (6).

4. The multi-atmosphere controllable alloy powder sintering furnace according to claim 3, characterized in that: An upward backflow space is reserved between the preheating air inlet plate (6) and the inner wall of the furnace body (2), and backflow guide plates (502) extending to the top of the upward backflow space are fixedly arranged on the two sides of the upper end of the preheating box (5).

5. The multi-atmosphere controllable alloy powder sintering furnace according to claim 1, characterized in that: The heat exchange pipes (7) are in U-shaped structure and are staggered with the heat radiation pipes (16) left and right, the two free ends of the heat exchange pipes (7) are arranged towards the preheating zone, one of the free ends of the heat exchange pipes (7) is connected with an extension section, the extension section penetrates through the lower end of the preheating box (5) and extends to the outside of the top of the conveying outer box (1), and the other free end of the heat exchange pipes (7) is connected with the U-shaped communication box (8) as a conveying end.

6. The multi-atmosphere controllable alloy powder sintering furnace according to claim 1, characterized in that: The reducing atmosphere conveying structure comprises air inlet pipes (11) embeddedly installed on the top of a plurality of arc-shaped cyclone grooves (201) arranged left and right, the upper ends of the air inlet pipes (11) extend outward and are commonly connected with a gas supply pipe (12), and air supply nozzles (13) are connected to the lower ends of the air inlet pipes (11).

7. The multi-atmosphere controllable alloy powder sintering furnace according to claim 1, characterized in that: The arc-shaped flow distribution plate (9) is an arc-shaped structure concentrically arranged with the furnace body (2), and the flow guide plate (10) is a convex structure, one end of the flow guide plate (10) located inside the arc-shaped cyclone groove (201) is provided with a rounded corner, and the two flow guide plates (10) located outside the arc-shaped cyclone groove (201) are arranged in proximity.

8. The multi-atmosphere controllable alloy powder sintering furnace according to claim 7, characterized in that: The flow guide plate (10) and the inner end wall of the arc-shaped cyclone groove (201) are reserved with flow field downward passages, and the widths of the multiple flow field downward passages distributed along the annular direction of the arc-shaped cyclone groove (201) decrease from top to bottom.

9. The multi-atmosphere controllable alloy powder sintering furnace according to claim 1, characterized in that: The cooling assembly is embedded and installed at the top of the cooling zone, which comprises a cooling box (14) embedded and installed at the top of the cooling zone and externally connected with an air inlet pipe two (141), and the lower end of the cooling box (14) is fixedly connected with heat exchange ventilation plates (15) which are also arc-shaped structures, and a plurality of heat exchange holes are distributed on the opposite end walls of the pair of heat exchange ventilation plates (15).

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