Vacuum tungsten mesh sintering furnace

Abstract

The invention relates to the field of sintering furnaces, in particular to a vacuum tungsten mesh sintering furnace which comprises a furnace body, the furnace body is fixed to a furnace frame, a lifting mechanism is arranged on the furnace frame, a furnace bottom cover is fixed to the lifting mechanism and detachably connected with the furnace body, and a first reflecting screen, a third reflecting screen and a material table are sequentially fixed to the furnace bottom cover from bottom to top. The first reflecting screen is connected with a third reflecting screen in an opening and closing mode, a tungsten mesh heating body is arranged on the inner side of the third reflecting screen, and a gas inlet and outlet mechanism is arranged between the third reflecting screen and the furnace body. The overall stability of the third reflecting screen is improved, meanwhile, the hydrogen can be well preheated in the process that the hydrogen passes through the supporting pipe, the stability of the temperature in the furnace can be guaranteed after the hydrogen is preheated and then enters the furnace, then the material sintering effect and efficiency are improved, and meanwhile the effect of saving energy is achieved.

Description

Technical Field

[0001] The invention relates to the field of sintering furnaces, in particular to a vacuum tungsten mesh sintering furnace. Background Art

[0002] The vacuum tungsten mesh sintering furnace is a furnace that performs protective sintering in a vacuum environment, and mainly uses tungsten mesh as the heating element. This sintering furnace is usually used in laboratory scientific research or industrial production. It has the characteristics of ultra-high temperature and high vacuum. It uses tungsten mesh to generate heat in a vacuum environment and heats through thermal radiation conduction. It is suitable for vacuum heat treatment processes of various high-temperature alloy materials, stainless steel, high-speed steel, ceramics and other materials, such as brazing, sintering, solution treatment, annealing, etc. The vacuum tungsten mesh sintering furnace usually adopts a vertical structure, and the main components include electric furnace body, vacuum system, water cooling system, pneumatic system, hydraulic system, feeding and discharging mechanism, etc. Its heating element is tungsten mesh, combined with advanced thermal insulation materials to ensure stable operation in high temperature and vacuum environment. A reflective screen is often set in a vacuum tungsten mesh sintering furnace for heat preservation and insulation. For example, the patent with application number CN201320754104.2 discloses a high-temperature hydrogen sintering furnace. The reflective screen of the high-temperature hydrogen sintering furnace has good insulation effect, effectively reduces heat loss, makes the furnace heat up quickly, has high thermal efficiency and improves the furnace temperature. However, the reflective screen still has the following disadvantages during use: 1) Since the reflective screen is composed of multiple layers of metal sheets, each layer of metal sheets is very thin, so for the reflective screen as a whole, it is easy to deform and the supporting effect is poor; 2) The upper reflective screen and the side reflective screen of the reflective screen are connected together by flanges. In this connection method, heat will still be lost from the gap between the upper reflective screen and the side reflective screen, affecting the insulation effect.

[0003] During the sintering process of the vacuum tungsten mesh sintering furnace, it is often necessary to pass a slightly positive pressure of flowing hydrogen into the furnace to reduce the oxides in the furnace. The common method of passing hydrogen is to pass it from the top of the sintering furnace, then lead it out from the bottom, and connect the igniter to burn the excess hydrogen. However, this method of passing hydrogen often has the following disadvantages: 1) Since hydrogen is relatively light, hydrogen passing from the top of the sintering furnace often gathers in the upper part of the sintering furnace, and slowly spreads downward with the hydrogen passing until the entire sintering furnace is filled. As a result, each time the new hydrogen entering the sintering furnace is often gathered in the upper part of the sintering furnace, it will make the new hydrogen unable to react with the oxides in the furnace in a timely and comprehensive manner, resulting in poor reduction efficiency and effect; 2) The moment the external hydrogen is directly passed into the furnace, it will absorb more heat in the furnace, which will have an adverse effect on sintering and waste more heat energy.

[0004] In summary, there is an urgent need for a vacuum tungsten mesh sintering furnace that has good reflective screen support and thermal insulation effects, and can improve reduction efficiency and effect and save energy when passing reducing atmosphere hydrogen. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a vacuum tungsten mesh sintering furnace, which solves the problems existing in the prior art. The vacuum tungsten mesh sintering furnace not only plays a good supporting role for the metal sheet through the arrangement of the support tube, effectively prevents the deformation of the thin metal sheet, and improves the overall stability of the third reflective screen, but also has a good preheating effect on the hydrogen in the process of hydrogen passing through the support tube. After the hydrogen is preheated, it enters the furnace to ensure the stability of the temperature in the furnace, thereby improving the sintering effect and efficiency of the material, and also saving energy.

[0007] (II) Technical solution

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a vacuum tungsten mesh sintering furnace, comprising a furnace body, the furnace body is fixed on a furnace frame, a lifting mechanism is provided on the furnace frame, a furnace bottom cover is fixed on the lifting mechanism, the furnace bottom cover is detachably connected to the furnace body, a first reflection screen, a third reflection screen and a material table are fixed to the furnace bottom cover in sequence from bottom to top, the first reflection screen is openably connected to the third reflection screen, a tungsten mesh heating body is provided on the inner side of the third reflection screen, a gas inlet and outlet mechanism is provided between the third reflection screen and the furnace body, and a vacuum pumping mechanism is provided on the furnace body.

[0009] Preferably, the third reflection screen is composed of several layers of metal sheets, each layer of metal sheets is composed of an annular metal sheet and a cylindrical metal sheet fixed on the top of the annular metal sheet, and a gap is left between two adjacent layers of metal sheets.

[0010] Preferably, the gas inlet and outlet mechanism includes a plurality of support tubes fixed in the gap, the support tubes include a longitudinal support section and a transverse support section, the end of the longitudinal support section is connected to a gas outlet collecting pipe, the end of the transverse support section is connected to a gas inlet collecting pipe, the gas inlet collecting pipe is connected to an inflation mechanism, a first gas inlet port is provided on the third reflective screen, and a second gas inlet port is provided on the furnace body.

[0011] Preferably, four support tubes are evenly fixed in the gap, and the longitudinal support sections in the gaps form four rows.

[0012] Preferably, a plurality of groups of staggered plates are arranged in the longitudinal support section, each group of staggered plates is composed of a first staggered plate and a second staggered plate, and the first staggered plate and the second staggered plate are both inclined downward from the fixed end to the free end.

[0013] Preferably, the innermost metal sheet of the third reflective screen is a tungsten sheet, and the remaining metal sheets are molybdenum sheets.

[0014] Preferably, the lifting mechanism includes a motor fixed on the furnace frame, a transmission rod is fixed on the output shaft of the motor, a pair of bevel gear groups are connected to the left and right ends of the transmission rod, one gear of each pair of bevel gear groups is fixed on the transmission rod, one end of the screw rod is fixed to the other gear, the other end of the screw rod is rotatably connected to the top of the furnace frame, a nut seat matching the screw rod is provided on the screw rod, a lifting plate is fixed between the two nut seats, a fixed seat is fixed on the lifting plate, and a furnace bottom cover is fixed on the fixed seat.

[0015] Preferably, the vacuum mechanism includes a mechanical pump connected to a molecular pump, the molecular pump is connected to the furnace body 1 through a connecting pipe, a heat insulation mechanism and a cold trap are arranged in the connecting pipe, the heat insulation mechanism is arranged on a side close to the furnace body, and the cold trap is arranged on a side close to the molecular pump.

[0016] Preferably, the heat insulation mechanism includes a plurality of heat insulation plates fixed on the inner wall of the connecting pipe, with gaps left between adjacent heat insulation plates, and the heat insulation plates are arranged in a grid plate shape, which is composed of a plurality of rows of grids, and each row of grids is composed of a plurality of grids.

[0017] Preferably, a refractory ball is provided every other grid on the grid row, the refractory ball is rotatably connected to the grid on which it is provided, the refractory balls in two adjacent grid rows are staggered, and the refractory balls on two adjacent insulation boards are staggered.

[0018] (III) Beneficial effects

[0019] 1. The present invention provides a good support for the metal sheet through the setting of the support tube, effectively prevents the deformation of the thin metal sheet, and improves the overall stability of the third reflective screen. At the same time, after the metal sheets are connected and fixed by the support tube, there is no need to perform additional fixed connection between the metal sheets. In the prior art, all metal sheets are connected and fixed by more fixing parts penetrating all layers of metal sheets. This method of fixing the metal sheets through the support tube reduces the damage to the third reflective screen while improving the thermal insulation effect. In addition, the support tube is also a pipeline for hydrogen to be introduced. The hydrogen enters the furnace after passing through the support tube, which has the following advantages compared to the method of directly introducing hydrogen from the top of the sintering furnace in the prior art: 1) The process of hydrogen passing through the support tube can preheat the hydrogen well. The hydrogen enters the furnace after being preheated, which can ensure the stability of the temperature in the furnace, thereby improving the sintering effect and efficiency of the material, and also saving energy; 2) Hydrogen After passing through the support tube, the gas enters the space surrounded by the first reflective screen and the third reflective screen through the gas outlet manifold. Hydrogen enters from the bottom of the space, then moves upward, and finally is drawn out from the first gas outlet. Since hydrogen is very light, it enters from the bottom and will have an upward process. This process from bottom to top allows the hydrogen to have full and comprehensive contact with the oxide in the space, thereby greatly improving the efficiency and effect of the reduction reaction; 3) Hydrogen enters from the bottom, so that the hydrogen entering the space surrounded by the first reflective screen and the third reflective screen always has an upward pushing force on the gas in the space, making it easier for the gas in the upper part of the space to be drawn out through the first gas outlet, ensuring the fluidity of the hydrogen in the space; 4) The reduction reaction mainly occurs in the space surrounded by the first reflective screen and the third reflective screen. Compared with the prior art in which hydrogen is passed into the entire furnace body, the reaction space is greatly reduced, which not only saves resources such as hydrogen, but also improves the efficiency and effect of the reduction reaction.

[0020] 2. The present invention arranges the metal sheets constituting the third reflective screen to be integrally formed of annular metal sheets and cylindrical metal sheets. On the one hand, the sealing performance is greatly improved, thereby improving the thermal insulation effect and saving energy. On the other hand, the installation is greatly facilitated, and at the same time, the stability of the metal sheets is also improved to a certain extent.

[0021] 3. In the process of cleaning the furnace after sintering, the two-way nitrogen introduction not only safely and efficiently removes the remaining hydrogen in the furnace, but also achieves the effect of rapidly cooling the furnace.

[0022] 4. The present invention evenly distributes the support tubes into four rows in the gap, so that each row of support tubes forms a concentrated support area, which not only improves the support effect of the third reflective screen, but also forms a concentrated heat storage area in each row of support tubes. In this way, when hydrogen passes through the support tubes, the heating effect and efficiency of hydrogen can be improved, thereby ultimately improving the sintering effect and efficiency of the material.

[0023] 5. The present invention arranges staggered plates in the longitudinal support section, which, on the one hand, enhances the overall heat storage capacity of the longitudinal support section, thereby enhancing the heating effect on the hydrogen; on the other hand, the staggered plates can play a good mixing role on the hydrogen, making the heating of the hydrogen more comprehensive and uniform. In addition, the time that the hydrogen stays in the longitudinal support section is prolonged, further improving the heating effect on the hydrogen.

[0024] 6. The present invention arranges the metal sheet to be composed of tungsten sheet and molybdenum sheet, so that the tungsten sheet and the molybdenum sheet can efficiently reflect heat during the sintering process, reduce heat loss, save energy, and also play a good role in thermal insulation. The innermost metal sheet is set to be a tungsten sheet, because the innermost metal sheet is closest to the second molybdenum wire heating body, and the tungsten sheet has higher high temperature resistance, hardness and deformation resistance than the molybdenum sheet, thereby improving the overall stability and service life of the third reflective screen.

[0025] 7. The present invention achieves a better vacuuming effect by arranging a mechanical pump, a molecular pump and a cold trap. By arranging a heat-insulating mechanism in the connecting pipe, a good heat-insulating effect can be achieved to ensure the temperature stability of the furnace body. At the same time, the heat-insulating mechanism absorbs heat in advance, which greatly reduces the working pressure of the cold trap. The heat storage capacity of the heat-insulating mechanism is further improved by the arrangement of refractory balls, wherein the refractory balls are arranged to be rotatably connected with the grid, so that the refractory balls can rotate when the gas passes through, making the heat absorption more comprehensive and sufficient, further improving the heat absorption effect, and thus improving the heat preservation and heat insulation effect. The refractory balls on two adjacent insulation boards are arranged in staggered grids, so that the path of the gas through the entire heat-insulating mechanism is more tortuous and long, so that the heat storage effect of the entire heat-insulating mechanism is better, thereby achieving a good heat preservation and heat insulation and energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is an overall schematic diagram of the present invention.

[0027] Figure 2 It is a cross-sectional view of the third reflection screen of the present invention.

[0028] Figure 3 It is a schematic diagram of a metal sheet of the present invention.

[0029] Figure 4 It is a three-dimensional schematic diagram of a metal sheet of the present invention.

[0030] Figure 5 It is a cross-sectional view of the third reflection screen and the support tube of the present invention.

[0031] Figure 6 It is a cross-sectional view of the third reflective screen, the support tube, the air outlet manifold, the air inlet manifold and the inflation mechanism of the present invention.

[0032] Figure 7 Schematic diagram of the support tube of the present invention.

[0033] Figure 8 For the present invention Figure 1 Schematic diagram after adding the insulation mechanism.

[0034] Fig. 9 It is a schematic diagram of the longitudinal support section and staggered plates of the present invention.

[0035] Fig.10 It is a schematic diagram of the longitudinal support section, the first staggered plate and the second staggered plate of the present invention.

[0036] Fig.11 It is a cross-sectional view of the third reflection screen of the present invention.

[0037] Fig.12 It is a schematic diagram of the heat insulation mechanism of the present invention.

[0038] Fig.13 The figure is a schematic diagram of a heat insulation board and the refractory balls thereon according to the present invention.

[0039] In the figure: 1-furnace body, 2-furnace frame, 3-lifting mechanism, 4-furnace bottom cover, 5-first reflection screen, 6-third reflection screen, 7-material table, 8-third reflection screen, 9-tungsten mesh heating body, 10-gas inlet and outlet mechanism, 11-vacuum extraction mechanism, 12-metal sheet, 13-annular metal sheet, 14-cylindrical metal sheet, 15-gap, 16-support tube, 17-longitudinal support section, 18-lateral support section, 19-gas outlet manifold, 20-gas inlet manifold, 21-inflating mechanism, 22-first Gas outlet, 23-second gas outlet, 24-interlaced plate, 25-first interlaced plate, 26-second interlaced plate, 27-tungsten sheet, 28-molybdenum sheet, 29-motor, 30-transmission rod, 31-bevel gear set, 32-screw rod, 33-nut seat, 34-lifting plate, 35-fixed seat, 36-mechanical pump, 37-molecular pump, 38-connecting pipe, 39-insulation mechanism, 40-cold trap, 41-insulation board, 42-gap, 43-grid row, 44-grid, 45-refractory ball. DETAILED DESCRIPTION

[0040] The following will be combined with the attached embodiment of the present invention Figure 1-13The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The present invention provides a technical solution: a vacuum tungsten mesh sintering furnace, comprising a furnace body 1, the furnace body 1 is fixed on a furnace frame 2, the furnace frame 2 is provided with a lifting mechanism 3, a furnace bottom cover 4 is fixed on the lifting mechanism 3, the furnace bottom cover 4 is detachably connected to the furnace body 1, the furnace bottom cover 4 is fixed with a first reflection screen 5, a third reflection screen 6 and a material platform 7 from bottom to top, the first reflection screen 5 is openably connected to the third reflection screen 8, a tungsten mesh heating body 9 is provided on the inner side of the third reflection screen 8, a gas inlet and outlet mechanism 10 is provided between the third reflection screen 8 and the furnace body 1, a vacuum pumping mechanism 11 is provided on the furnace body 1, the third reflection screen 8 is composed of a plurality of layers of metal sheets 12, each The layer metal sheet 12 is composed of an annular metal sheet 13 and a cylindrical metal sheet 14 fixed on the top of the annular metal sheet 13. A gap 15 is left between two adjacent layers of metal sheets 12. The gas inlet and outlet mechanism 10 includes a plurality of support pipes 16 fixed in the gap 15. The support pipe 16 includes a longitudinal support section 17 and a transverse support section 18. The end of the longitudinal support section 17 is connected to a gas outlet manifold 19. The end of the transverse support section 18 is connected to an gas intake manifold 20. The gas intake manifold 20 is connected to an inflation mechanism 21. A first gas outlet 22 is provided on the third reflection screen 8, and a second gas outlet 23 is provided on the furnace body 1. During operation, first, the lifting mechanism 3 lowers the furnace bottom cover 4 to the bottom of the furnace frame 2, and then puts the material on the material platform 7, and then the lifting mechanism 3 raises the furnace bottom cover 4 until the furnace bottom cover 4 is closed with the furnace body 1, wherein the furnace bottom cover 4 and the furnace body 1 can be locked by screws, nuts and other locking parts after closing, and then the furnace body 1 is evacuated by the vacuum pumping mechanism 11, and then the tungsten mesh heating body 9 is started to heat and sinter the material, and during the sintering process, the reducing atmosphere hydrogen is filled into the air intake manifold 20 through the charging mechanism 21, and the hydrogen enters the horizontal support section 18 through the air intake manifold 20, and then enters the longitudinal support section 17, and then enters the space surrounded by the first reflection screen 5 and the third reflection screen 8 from the air outlet manifold 19, and reacts with the oxides therein, and then enters the space between the first reflection screen 5, the third reflection screen 8 and the furnace body 1 from the first gas outlet 22, and finally is led out from the second gas outlet 23, and hydrogen is continuously passed into the furnace until the sintering is completed. The heating body is set in the form of a tungsten mesh. Compared with a plate or rod-shaped form, this mesh form is easier to eliminate stress during heating and sintering, and has a longer service life. The second gas outlet 23 can be connected to an igniter, so that the gas drawn from the furnace is burned by the igniter, wherein the igniter can be a silicon nitride igniter. Since the hydrogen in the furnace needs to maintain fluidity, that is, hydrogen must be continuously passed into the furnace, and the furnace must be kept in a state of slight positive pressure, an automatic pressure relief valve can be connected to the outer ends of the first gas outlet 22 and the second gas outlet 23, so that the pressure in the furnace can be automatically adjusted, so that the furnace always maintains the required slight positive pressure state.After sintering, there is still a lot of hydrogen left in the furnace. If the hydrogen is not handled in time, it is very dangerous and there is a risk of explosion. It is also unsafe to extract the hydrogen by vacuuming, which poses a great risk. Therefore, the furnace is cleaned by passing a sufficient amount of nitrogen into the furnace to drive the hydrogen out of the furnace. The specific method of cleaning the furnace after sintering is as follows: nitrogen is filled into the inlet manifold 20 through the atmosphere filling system, and the nitrogen is filled in two ways. One way of nitrogen enters the horizontal support section 18, the longitudinal support section 17 and the outlet manifold 19. In the space surrounded by the first reflective screen 5 and the third reflective screen 8, the hydrogen in the space is driven upward and enters the upper space between the first reflective screen 5, the third reflective screen 8 and the furnace body 1 through the first gas outlet 22. Another nitrogen gas is introduced from the bottom of the furnace body 1. A nitrogen inlet is provided at the bottom of the furnace body 1, and the nitrogen inlet is connected to the gas filling system. The hydrogen in the first reflective screen 5, the third reflective screen 8 and the furnace body 1 is driven upward by the introduction of nitrogen, and the hydrogen driven to the upper part is finally burned by the igniter through the second gas outlet 23. The gas filling mechanism 21 is a conventional technical means in this field, and its specific structure is not repeated here. The first reflective screen 5 is also composed of a plurality of cylindrical metal sheets, which can just cover the opening at the bottom of the third reflective screen 8, so that the first reflective screen 5 and the third reflective screen 8 form a closed space. The third reflective screen 6 is also composed of a plurality of cylindrical metal sheets, which can enhance the thermal insulation performance of the bottom of the furnace body 1. The present invention arranges the metal sheet 12 constituting the third reflective screen 8 to be integrally formed by an annular metal sheet 13 and a cylindrical metal sheet 14. Compared with the method in which the upper reflective screen and the side reflective screen are connected and fixed by flanges in the comparative document CN201320754104.2, on the one hand, the sealing is greatly improved, thereby improving the effect of thermal insulation and saving energy. On the other hand, it greatly facilitates the installation and improves the stability of the metal sheet 12 to a certain extent.The present invention provides a good support for the metal sheet 12 through the setting of the support tube 16, effectively preventing the deformation of the thin metal sheet 12 and improving the overall stability of the third reflective screen 8. At the same time, after the metal sheet 12 is connected and fixed by the support tube 16, there is no need to perform additional fixed connection between the metal sheets 12. In the prior art, all metal sheets are connected and fixed by a plurality of fixing parts penetrating all layers of metal sheets 12. This method of fixing the metal sheets 12 through the support tube 16 reduces damage to the third reflective screen 8 while improving the thermal insulation effect. In addition, the support tube 16 is also a pipeline for hydrogen to be introduced. The hydrogen enters the furnace after passing through the support tube 16, which has the following advantages compared to the method of directly introducing hydrogen from the top of the sintering furnace in the prior art: 1) The process of hydrogen passing through the support tube 16 can preheat the hydrogen well. The hydrogen enters the furnace after being preheated, which can ensure the stability of the temperature in the furnace, thereby improving the sintering effect and efficiency of the material, and also saving energy. ; 2) After passing through the support tube 16, the hydrogen enters the space surrounded by the first reflective screen 5 and the third reflective screen 8 through the gas outlet manifold 19. The hydrogen enters from the bottom of the space, then moves upward, and finally is drawn out from the first gas outlet 22. Since hydrogen is very light, it enters from the bottom and will have an upward process. This process from bottom to top allows the hydrogen to fully and comprehensively contact with the oxide in the space, thereby greatly improving the efficiency and effect of the reduction reaction; 3) Hydrogen enters from the bottom, so that the hydrogen entering the space surrounded by the first reflective screen 5 and the third reflective screen 8 always has an upward pushing force on the gas in the space, making it easier for the gas in the upper part of the space to be drawn out through the first gas outlet 22, ensuring the fluidity of the hydrogen in the space; 4) The reduction reaction mainly occurs in the space surrounded by the first reflective screen 5 and the third reflective screen 8. Compared with the prior art in which hydrogen is passed into the entire furnace body, the reaction space is greatly reduced, which not only saves resources such as hydrogen, but also improves the efficiency and effect of the reduction reaction. In the process of cleaning the furnace after sintering, the two-way nitrogen gas introduction not only safely and efficiently removes the remaining hydrogen in the furnace, but also achieves the effect of rapidly cooling the furnace.

[0042] Four support tubes 16 are evenly fixed in the gap 15, and the longitudinal support sections 17 in the gaps 15 form four rows, wherein the longitudinal support sections 17 are arranged and distributed as follows: Figure 5 As shown, the arrangement evenly divides the third reflective screen 8 into four areas through the support tubes 16, wherein each column of support tubes 16 forms a centralized support area, which not only improves the support effect of the third reflective screen 8, but also each column of support tubes 16 forms a centralized heat storage area, so that when hydrogen passes through the support tubes 16, the heating effect and efficiency of hydrogen can be improved, thereby ultimately improving the sintering effect and efficiency of the material. The material of the support tubes 16 can be tungsten or molybdenum.

[0043] A plurality of groups of staggered plates 24 are arranged in the longitudinal support section 17, each group of staggered plates 24 is composed of a first staggered plate 25 and a second staggered plate 26, the first staggered plate 25 and the second staggered plate 26 are both inclined downward from the fixed end to the free end, wherein the material of the first staggered plate 25 and the second staggered plate 26 can be tungsten or molybdenum. The arrangement of the staggered plates 24 can enhance the overall heat storage capacity of the longitudinal support section 17 on the one hand, thereby enhancing the heating effect of hydrogen, and on the other hand, the staggered plates 24 can play a good mixing role for hydrogen, making the heating of hydrogen more comprehensive and uniform, and also prolonging the time of hydrogen in the longitudinal support section 17, further improving the heating effect of hydrogen.

[0044] The innermost metal sheet 12 of the third reflective screen 8 is a tungsten sheet 27, and the remaining metal sheets 12 are molybdenum sheets 28. The metal sheet 12 is configured to be composed of the tungsten sheet 27 and the molybdenum sheet 28, so that the tungsten sheet 27 and the molybdenum sheet 28 can efficiently reflect heat during the sintering process, reduce heat loss, save energy, and also play a good role in heat preservation. The innermost metal sheet 12 is configured to be the tungsten sheet 27, because the innermost metal sheet is closest to the tungsten mesh heating body 9, and the tungsten sheet has higher resistance to high temperatures, hardness, and deformation resistance than the molybdenum sheet. The thickness of the tungsten sheet 27 is 0.5mm, the thickness of the molybdenum sheet 28 closest to the tungsten sheet 27 is 0.3mm, and the thickness of the remaining molybdenum sheets 28 is 0.2mm. The thickness of the tungsten sheet 27 and the molybdenum sheet 28 should be neither too thick nor too thin. If they are too thick, the entire third reflective screen 8 will absorb relatively more heat during the heating process, making it store relatively more heat, which will cause the overall temperature rise in the sintering furnace to be slow. Therefore, the thinner the tungsten sheet 27 and the molybdenum sheet 28, the better. However, when it is thin to a certain extent, it becomes more difficult to process, the processing cost is also high, and the supporting effect is poor and it is easy to crack. Therefore, the thickness of the tungsten sheet 27 is 0.5mm, the thickness of the molybdenum sheet 28 closest to the tungsten sheet 27 is 0.3mm, and the thickness of the remaining molybdenum sheets 28 is 0.2mm. This thickness is the best thickness after overall consideration.

[0045] The lifting mechanism 3 includes a motor 29 fixed on the furnace frame 2, a transmission rod 30 is fixed on the output shaft of the motor 29, and a pair of bevel gear sets 31 are connected to the left and right ends of the transmission rod 30, one of the gears of each pair of bevel gear sets 31 is fixed on the transmission rod 30, and the other gear is fixed to one end of a screw rod 32, and the other end of the screw rod 32 is rotatably connected to the top of the furnace frame 2, and a nut seat 33 matching it is provided on the screw rod 32, and a lifting plate 34 is fixed between the two nut seats 33, and a fixed seat 35 is fixed on the lifting plate 34, and a furnace bottom cover 4 is fixed on the fixed seat 35. The lifting mechanism 3 belongs to the prior art, and the bevel gear set 31 also belongs to the prior art, and a protective box is provided on the outside. When working, the motor 29 is started, and then the transmission rod 30 is driven to rotate, and then the bevel gear set 31 is driven to rotate, and then the screw rod 32 is driven to rotate, and then the nut seat 33 is driven to rotate, and then the lifting plate 34 is driven to rise or fall, and finally the furnace bottom cover 4 is driven to close or separate from the furnace body 1.

[0046] The vacuum pumping mechanism 11 includes a mechanical pump 36, which is connected to a molecular pump 37. The molecular pump 37 is connected to the furnace body 1 through a connecting pipe 38. A heat insulation mechanism 39 and a cold trap 40 are arranged in the connecting pipe 38. The heat insulation mechanism 39 is arranged on a side close to the furnace body 1, and the cold trap 40 is arranged on a side close to the molecular pump 37. The arrangement of the mechanical pump 36, the molecular pump 37 and the cold trap 40 makes the vacuum pumping effect better. In order to improve the efficiency of vacuum pumping, the diameter of the connecting pipe 38 is often set to be relatively large. However, once the diameter of the connecting pipe 38 is set to be large, it will cause the heat in the furnace body 1 to dissipate, thereby affecting the heat preservation effect in the furnace body 1. Therefore, the heat insulation effect in the furnace body 1 is enhanced by arranging the heat insulation mechanism 39 in the connecting pipe 38.

[0047] The heat insulation mechanism 39 includes a plurality of heat insulation plates 41 fixed on the inner wall of the connecting pipe 38, and a gap 42 is left between adjacent heat insulation plates 41. The heat insulation plates 41 are arranged in a grid plate shape, which is composed of a plurality of grid rows 43, and each grid row 43 is composed of a plurality of grids 44. The material of the heat insulation plates 41 can be tungsten or molybdenum, which can play a good role in heat storage. When the vacuum is evacuated, when the gas in the furnace body 1 passes through the heat insulation plates 41, the heat of the gas will be absorbed by the heat insulation plates 41. After the gas passes through the layers of heat insulation plates 41, most of the heat will be absorbed by the heat insulation plates 41. In this way, when the gas reaches the cold trap 40 for cooling, the heat insulation mechanism 39 can play a good heat insulation effect, ensuring the stability of the temperature in the furnace body 1. At the same time, the heat insulation mechanism 39 absorbs heat in advance, which greatly reduces the working pressure of the cold trap 40. The number of heat insulation plates 41 is set according to actual needs.

[0048] A refractory ball 45 is provided every other grid 44 on the grid row 43, and the refractory ball 45 is rotatably connected to the grid 44 on which it is provided. The refractory balls 45 in two adjacent grid rows 43 are staggered, and the refractory balls 45 on two adjacent insulation boards 41 are staggered. This arrangement further improves the heat storage effect of the insulation board 41 under the premise of ensuring a large flow of gas. The refractory balls 45 are arranged to be rotatably connected to the grid 44, so that the refractory balls 45 can rotate when the gas passes through, making the heat absorption more comprehensive and sufficient, further improving the heat absorption effect, and thus improving the heat preservation and heat insulation effect. The refractory balls 45 on two adjacent insulation boards 41 are staggered, so that the path of the gas passing through the entire insulation mechanism 39 is more tortuous and long, so that the heat storage effect of the entire insulation mechanism 39 is better, thereby achieving a good heat preservation and heat insulation and energy saving effect.

[0049] Working principle: When working,.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A vacuum tungsten mesh sintering furnace, characterized in that: The invention comprises a furnace body (1), wherein the furnace body (1) is fixed on a furnace frame (2), the furnace frame (2) is provided with a lifting mechanism (3), a furnace bottom cover (4) is fixed on the lifting mechanism (3), the furnace bottom cover (4) is detachably connected to the furnace body (1), a first reflection screen (5), a third reflection screen (6) and a material table (7) are fixed to the furnace bottom cover (4) in sequence from bottom to top, the first reflection screen (5) is openably connected to the third reflection screen (8), a tungsten mesh heating body (9) is provided on the inner side of the third reflection screen (8), a gas inlet and outlet mechanism (10) is provided between the third reflection screen (8) and the furnace body (1), and a vacuum pumping mechanism (11) is provided on the furnace body (1).

2. A vacuum tungsten mesh sintering furnace according to claim 1, characterized in that: The third reflection screen (8) is composed of a plurality of layers of metal sheets (12), each layer of the metal sheets (12) being composed of an annular metal sheet (13) and a cylindrical metal sheet (14) fixed on the top of the annular metal sheet (13), and a gap (15) is left between two adjacent layers of the metal sheets (12).

3. A vacuum tungsten mesh sintering furnace according to claim 2, characterized in that: The gas inlet and outlet mechanism (10) comprises a plurality of support tubes (16) fixed in the gap (15), the support tubes (16) comprising a longitudinal support section (17) and a transverse support section (18), the end of the longitudinal support section (17) is connected to a gas outlet manifold (19), the end of the transverse support section (18) is connected to a gas inlet manifold (20), the gas inlet manifold (20) is connected to a gas charging mechanism (21), the third reflective screen (8) is provided with a first gas outlet (22), and the furnace body (1) is provided with a second gas outlet (23).

4. A vacuum tungsten mesh sintering furnace according to claim 3, characterized in that: Four support tubes (16) are evenly fixed in the gap (15), and the longitudinal support sections (17) in a plurality of the gaps (15) form four rows.

5. The vacuum tungsten mesh sintering furnace according to claim 3, characterized in that: A plurality of groups of staggered plates (24) are arranged in the longitudinal support section (17), each group of the staggered plates (24) being composed of a first staggered plate (25) and a second staggered plate (26), and the first staggered plates (25) and the second staggered plates (26) are both inclined downward from the fixed end to the free end.

6. The vacuum tungsten mesh sintering furnace according to claim 1, characterized in that: The innermost metal sheet (12) of the third reflective screen (8) is a tungsten sheet (27), and the remaining metal sheets (12) are molybdenum sheets (28).

7. The vacuum tungsten mesh sintering furnace according to claim 1, characterized in that: The lifting mechanism (3) comprises a motor (29) fixed to the furnace frame (2), a transmission rod (30) being fixed to the output shaft of the motor (29), a pair of bevel gear sets (31) being connected to the left and right ends of the transmission rod (30), one gear of each pair of bevel gear sets (31) being fixed to the transmission rod (30), one end of a screw rod (32) being fixed to the other gear, the other end of the screw rod (32) being rotatably connected to the top of the furnace frame (2), a nut seat (33) matching the screw rod (32) being provided on the screw rod (32), a lifting plate (34) being fixed between the two nut seats (33), a fixing seat (35) being fixed on the lifting plate (34), and the furnace bottom cover (4) being fixed on the fixing seat (35).

8. The vacuum tungsten mesh sintering furnace according to claim 1, characterized in that: The vacuum pumping mechanism (11) comprises a mechanical pump (36), the mechanical pump (36) being connected to a molecular pump (37), the molecular pump (37) being connected to the furnace body (1) via a connecting pipe (38), a heat insulating mechanism (39) and a cold trap (40) being arranged in the connecting pipe (38), the heat insulating mechanism (39) being arranged on a side close to the furnace body (1), and the cold trap (40) being arranged on a side close to the molecular pump (37).

9. The vacuum tungsten mesh sintering furnace according to claim 8, characterized in that: The heat insulation mechanism (39) comprises a plurality of heat insulation plates (41) fixed on the inner wall of the connecting pipe (38), with gaps (42) being left between adjacent heat insulation plates (41), and the heat insulation plates (41) being arranged in a grid plate shape, which is composed of a plurality of grid rows (43), and each of the grid rows (43) is composed of a plurality of grids (44).

10. The vacuum tungsten mesh sintering furnace according to claim 9, characterized in that: A refractory ball (45) is provided every other lattice (44) on the lattice row (43); the refractory ball (45) is rotatably connected to the lattice (44) on which it is provided; the refractory balls (45) in two adjacent lattice rows (43) are staggered; and the refractory balls (45) on two adjacent insulation boards (41) are staggered.

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