High-performance oxygen-enriched sintering device and sintering process for piezoresistor production

Abstract

The invention discloses a high-performance oxygen-enriched sintering device for piezoresistor production and a sintering process, and relates to the technical field of piezoresistor production. The high-performance oxygen-enriched sintering device for piezoresistor production comprises a sintering device body, a base is fixed to the lower end of the sintering device body, and a smoke outlet is formed in the upper end of the sintering device body; a filtering box is fixed to the position, provided with the smoke exhaust port, of the upper end of the sintering device body, a smoke exhaust pipe is fixed to the upper end of the filtering box, a sintering cavity protection door is installed on the side face of the sintering device body, and a controller is fixed to the side face of the sintering device body. The sintering device is provided with a waste heat recovery structure used for conducting waste heat recovery and reutilization on flue gas. In the using process, heat in the flue gas can be recycled through the waste heat recycling structure, the recycled heat can preheat the resistor green body, and waste of resources can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of varistor production, and in particular to a high-performance oxygen-enriched sintering device and sintering process for varistor production. Background Art

[0002] In the overvoltage protection system of electronic circuits, varistors have become core protection components due to their nonlinear volt-ampere characteristics. Their key performance, such as response speed and energy absorption capacity, is highly dependent on the microstructural uniformity and grain size distribution of the ceramic body. This precise microstructural shaping is inseparable from high-precision sintering technology and professional sintering equipment, which provide the necessary conditions for the densification and crystal phase transformation of the ceramic body by precisely controlling the temperature field and atmosphere environment.

[0003] After the isostatically pressed resistor green body is smoothly placed inside the sintering device, the entire system enters the precision control phase. First, a gradient temperature increase is used to slowly break through the glass phase melting point to ensure uniform diffusion of the additives. Within the main sintering temperature range, a closed-loop control system maintains temperature fluctuations within the furnace chamber within ±2°C. Combined with the directional flow of inert gas, this ensures that the ceramic body completes grain growth and eliminates pores in an oxidizing-free environment. Finally, a stepped cooling process fully releases internal stresses in the material, forming a ceramic matrix with stable piezoresistive properties.

[0004] Existing varistor sintering devices emit high-temperature flue gas during the sintering process of resistor green bodies. These flue gases carrying a large amount of heat are usually discharged directly after treatment and purification, resulting in part of the process energy consumption being lost in the form of waste heat, causing a certain amount of energy waste. Summary of the Invention

[0005] The purpose of this application is to solve the problem that the existing sintering device mentioned in the above background technology generates flue gas carrying a large amount of heat during the sintering process, which is directly discharged after treatment and purification, resulting in a certain amount of energy waste. This application provides a high-performance oxygen-enriched sintering device and sintering process for the production of varistors.

[0006] In order to achieve the above-mentioned purpose, this application specifically adopts the following technical solutions: A high-performance oxygen-enriched sintering device for producing varistors includes a sintering device body, a base is fixed to the lower end of the sintering device body, a smoke exhaust port is provided at the upper end of the sintering device body, a filter box is fixed at the position of the smoke exhaust port at the upper end of the sintering device body, a smoke exhaust pipe is fixed to the upper end of the filter box, a sintering chamber protective door is installed on the side of the sintering device body, a controller is fixed to the side of the sintering device body, and a waste heat recovery structure for recovering and reusing waste heat from flue gas is provided on the sintering device.

[0007] By adopting the above technical solution, the sintering tray with the resistor green body is placed inside the sintering device body, the air path sealing is checked before starting, and then sintering is carried out. The sintering temperature and oxygen concentration are maintained and controlled during the sintering stage. When cooling after sintering, the oxygen supply is turned off, and the resistor green body is taken out of the furnace after cooling to 200°C. The above operation is repeated until all batches of resistor green bodies are sintered. During the sintering process, high-temperature flue gas floats out, and the waste heat in the flue gas can be recovered and reused through the waste heat recovery structure, reducing resource waste.

[0008] Furthermore, the waste heat recovery structure includes a mounting shell fixed to the end of the exhaust pipe away from the filter box, a guide pipe is fixed to the end of the mounting shell away from the exhaust pipe, a drive shaft is rotatably connected inside the mounting shell, an impeller is fixed on the drive shaft, a drive motor is fixed to the upper end of the sintering device body, the drive motor is electrically connected to the controller, one end of the drive shaft passes through the mounting shell and is fixedly connected to the output end of the drive motor, and a waste heat recycling component is provided on the side of the sintering device body.

[0009] By adopting the above technical solution, the waste heat recovery structure can recover and reuse the heat in the flue gas generated during the sintering process of the resistor green body, reducing the waste of resources caused by the heat in the flue gas drifting into the air.

[0010] Furthermore, the waste heat recycling component includes a preheating box fixed at the end of the sintering device body, a water storage chamber is opened inside the preheating box, the water storage chamber is used to accommodate water medium, a water supply pipe connected to the water storage chamber is fixed at the upper end of the preheating box, a drainage pipe connected to the water storage chamber is fixed at the lower end of the preheating box, a heat exchange coil is fixed at the end of the guide pipe away from the mounting shell, the heat exchange coil is located inside the water storage chamber, the heat exchange coil is a copper tube, and a vibration component is provided inside the preheating box.

[0011] By adopting the above technical solution, the waste heat recycling component can reuse the heat of the flue gas generated during the sintering process, and use the heat of the flue gas to preheat the resistor green body, thereby reducing the waste of resources.

[0012] Furthermore, several mounting plates are installed on the side of the preheating box, and a load-bearing net is fixed on the side of the mounting plate. The load-bearing net can be slidably inserted into the interior of the preheating box. A support bar is fixed inside the preheating box, and the frame of the load-bearing net fits with the support bar.

[0013] By adopting the above technical solution, when sintering the resistor green sheets, the next batch to be sintered is placed on the carrier net and placed inside the preheating box to preheat the resistor green sheets. This can reduce the heat required for subsequent sintering of the resistor green sheets and further reduce energy consumption during the sintering process.

[0014] Furthermore, a first magnetic strip is fixed to the side of the mounting plate, and a second magnetic strip that attracts the first magnetic strip is provided on the side of the preheating box.

[0015] By adopting the above technical solution, the first magnetic strip cooperates with the second magnetic strip to fix the cover, and the fixation is relatively convenient.

[0016] Furthermore, the rapping member includes a plurality of rotating shafts rotatably connected to the inside of the preheating box, and a rapping cam is fixed on the rotating shaft.

[0017] By adopting the above technical solution, the rotation of the rotating shaft drives the rapping cam to rotate. When the rapping cam rotates, it can rap the carrier network, causing the resistor placed on its surface to vibrate, thereby improving the preheating effect of the resistor green body.

[0018] Furthermore, pulleys are fixed to the end of the driving shaft and one of the ends of the rotating shaft, and the two pulleys are connected via a transmission belt.

[0019] By adopting the above technical solution, when the driving shaft rotates, one of the rotating shafts will rotate under the action of the pulley and the transmission belt, thereby playing a transmission role.

[0020] Furthermore, one end of the rotating shaft extends out of the preheating box and is fixed with a transmission gear, and two adjacent transmission gears are meshed with each other.

[0021] By adopting the above technical solution, when one of the rotating shafts rotates, the other rotating shafts also rotate accordingly under the action of the transmission gear.

[0022] A sintering process for producing a varistor comprises the following steps: S1: When loading the resistor green body on the heating plate, control the spacing between them to be 15±2mm, then open the sintering chamber protective door and place the sintering plate into the sintering device body; S2: Check the air circuit sealing before starting and ensure the nitrogen reserve is greater than 50m³; S3: During the heating stage, the temperature is raised to 600°C at a rate of 5°C / min and kept at this temperature for 30 minutes to remove the binder; S4: During the sintering stage, the temperature is maintained at 1150±5℃ and the oxygen concentration is controlled within the range of ±3% of the set value; S5: During the cooling phase, the oxygen supply is turned off and the temperature is lowered to 200°C at a rate of 10°C / min before being taken out of the furnace; S6: During sintering, the next batch of resistor green sheets to be sintered are placed on the carrier net. During the sintering process, the heat in the flue gas is used to preheat the resistor green sheets. S7: After sintering is completed, the preheated resistor green compacts are taken out and the above steps S1 to S6 are repeated until all batches of resistor green compacts are sintered.

[0023] In summary, the present application includes at least one of the following beneficial effects: 1. In the present application, when sintering resistor green sheets, the next batch of resistor green sheets to be sintered is placed on the carrier net, and then the carrier net is inserted into the preheating box. During the sintering process, the drive motor is turned on, and the drive motor drives the rotating shaft to rotate, causing the impeller to rotate, so that the flue gas passes through the exhaust pipe into the guide pipe and then into the heat exchange coil. The heat carried by the flue gas entering the heat exchange coil will be absorbed by the heat exchange coil, and the heat exchange coil will transfer the heat to the water inside the water storage chamber to heat the water, thereby increasing the temperature inside the preheating box. By increasing the temperature inside the preheating box, the resistor green sheets on the carrier net can be preheated, thereby realizing the recovery and reuse of heat in the flue gas, reducing resource waste, and reducing energy consumption during the sintering process.

[0024] 2. In this application, after the sintering technology of a batch of resistor green sheets is used, the sintered resistor green sheets are taken out, and then the resistor green sheets preheated inside the preheating box are taken out and placed inside the sintering device for sintering. By preheating the resistor green sheets, the heat required for the sintering process of the preheated resistor green sheets can be reduced, thereby further reducing the energy consumption during the sintering process.

[0025] 3. This application also preheats the resistor green body, which can significantly reduce the uneven heating of the resistor green body caused by the sudden temperature rise during the sintering process, thereby reducing the problems of stress concentration and structural defects inside the resistor green body and improving the sintering quality of the resistor green body.

[0026] 4. In this application, when the driving shaft drives the impeller to rotate, all the rotating shafts can rotate under the action of the pulley, the transmission belt and the transmission gear. When the rotating shaft rotates, the rapping cam follows the rotation. As the rapping cam continues to rotate, the supporting net will be vibrated. When the supporting net is vibrated, the resistor green sheets placed on its surface are vibrated, so that the resistor green sheets are fully in contact with the hot air inside the preheating box, thereby improving the preheating uniformity and preheating effect of the resistor green sheets.

[0027] 5. In this application, the vibration intensity is low-frequency micro-vibration, rather than strong impact, which loosens the micro-particles on the surface of the green body through low-frequency micro-vibration; and the vibration causes the resistor green body to slightly displace to avoid adhesion to the carrier mesh, ensuring uniform wrapping of the hot air flow. Moderate vibration can release the internal stress generated by pressing and reduce the risk of cracks in subsequent sintering. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a first three-dimensional structural diagram of the sintering device in this application; Figure 2 It is a second three-dimensional structural diagram of the sintering device in this application; Figure 3 This is a schematic diagram of the linkage structure of the impeller and the vibrating wheel in this application; Figure 4 It is a schematic diagram of the internal structure of the preheating box in this application; Figure 5 It is a schematic diagram of the three-dimensional structure of the heat exchange coil of the present application; Figure 6 It is a schematic diagram of the three-dimensional structure of the bearer network of this application; Figure 7 This application Figure 4 Enlarged schematic diagram of point A in the middle.

[0028] Description of reference numerals: 1. Sintering device body; 11. Base; 12. Filter box; 13. Smoke exhaust pipe; 14. Sintering chamber protective door; 15. Controller; 2. Waste heat recovery structure; 21. Mounting shell; 22. Guide pipe; 23. Drive shaft; 24. Impeller; 25. Drive motor; 3. Waste heat recycling component; 31. Preheating box; 32. Water storage chamber; 33. Heat exchange coil; 34. Mounting plate; 35. Carrying net; 36. Support bar; 37. First magnetic strip; 38. Second magnetic strip; 4. Vibrating member; 41. Rotating shaft; 42. Vibrating cam; 43. Pulley; 44. Drive belt; 45. Transmission gear. DETAILED DESCRIPTION

[0029] The following is combined with Figure 1-7 This application is described in further detail.

[0030] The embodiments of the present application disclose a high-performance oxygen-enriched sintering device and sintering process for producing varistor.

[0031] Reference Figure 1 and Figure 2 A high-performance oxygen-enriched sintering device for producing varistors includes a sintering device body 1, a base 11 is fixed at the lower end of the sintering device body 1, a smoke exhaust port is opened at the upper end of the sintering device body 1, a filter box 12 is fixed at the position of the smoke exhaust port at the upper end of the sintering device body 1, a smoke exhaust pipe 13 is fixed at the upper end of the filter box 12, a sintering chamber protective door 14 is installed on the side of the sintering device body 1, a controller 15 is fixed on the side of the sintering device body 1, and a waste heat recovery structure 2 for recovering and reusing waste heat from flue gas is provided on the sintering device.

[0032] Load the resistor green sheets on the heating plate, then open the sintering chamber protective door 14 and place the sintering plate into the sintering device body 1. Check the air path sealing before starting, and then carry out sintering. Maintain and control the sintering temperature and oxygen concentration during the sintering stage. When cooling after sintering, turn off the oxygen supply, cool to 200°C and then take it out of the furnace. Repeat the above operation until all batches of resistor green sheets are sintered. During the sintering process, high-temperature flue gas floats out and is filtered and purified by the filter box 12. Then, the waste heat in the flue gas can be recovered and reused through the waste heat recovery structure 2 to reduce resource waste.

[0033] Reference Figure 2-Figure 7 The waste heat recovery structure 2 includes an installation shell 21 fixed to the end of the smoke exhaust pipe 13 away from the filter box 12, and a guide pipe 22 is fixed to the end of the installation shell 21 away from the smoke exhaust pipe 13. The smoke exhaust pipe 13 and the guide pipe 22 are both provided with an insulation layer on the outside, which can effectively reduce the heat loss during the flue gas transportation process. The installation shell 21 is rotatably connected to the drive shaft 23, and the impeller 24 is fixed on the drive shaft 23. The upper end of the sintering device body 1 is fixed with a drive motor 25. The drive motor 25 is an adjustable speed motor. When working, it can drive the impeller 24 to rotate at a slower speed, thereby avoiding the problem of low waste heat recovery efficiency caused by excessive speed resulting in excessive flue gas flow rate. The drive motor 25 is electrically connected to the controller 15, and one end of the drive shaft 23 passes through the installation shell 21 and is fixedly connected to the output end of the drive motor 25. A waste heat recycling component 3 is provided on the side of the sintering device body 1.

[0034] Among them, the waste heat recycling component 3 includes a preheating box 31 fixed to the end of the sintering device body 1, and an insulation layer is provided on the outside of the preheating box 31, which can effectively reduce the heat loss inside the preheating box 31. A water storage chamber 32 is provided inside the preheating box 31, and the water storage chamber 32 is used to accommodate water medium. A water adding pipe connected to the water storage chamber 32 is fixed at the upper end of the preheating box 31, and the water adding pipe is used to add water to the inside of the preheating box 31. The lower end of the preheating box 31 is fixed with a A drain pipe is connected to the water storage chamber 32, and the drain pipe is used to discharge the water inside the water storage tank 32. A heat exchange coil 33 is fixed to the end of the guide pipe 22 away from the mounting shell 21. The heat exchange coil 33 is located inside the water storage chamber 32. The heat exchange coil 33 is a copper tube. The heat exchange coil 33 made of copper has good thermal conductivity, thereby improving the heat exchange efficiency. A water receiving box is provided at the lower end of the preheating box body 31 for collecting condensed water inside the heat exchange coil 33. A vibration component 4 is provided inside the preheating box body 31.

[0035] In addition, several mounting plates 34 are installed on the side of the preheating box 31, and a carrying net 35 is fixed on the side of the mounting plate 34. The carrying net 35 can be slidably inserted into the interior of the preheating box 31. A support bar 36 is fixed inside the preheating box 31, and the frame of the carrying net 35 fits with the support bar 36.

[0036] In addition, a first magnetic strip 37 is fixed to the side of the mounting plate 34 , and a second magnetic strip 38 that attracts the first magnetic strip 37 is provided on the side of the preheating box 31 .

[0037] When sintering the resistor green sheets, the next batch of resistor green sheets to be sintered is placed on the carrier mesh 35, and then the carrier mesh 35 is inserted into the preheating box 31 so that the frame of the carrier mesh 35 fits with the support bar 36. Then, under the action of the first magnet and the second magnet, the mounting plate 34 is fixed to the surface of the preheating box 31, and the resistor green sheets are placed on the surfaces of multiple carrier meshes 35 in turn and connected to the preheating box 31. During the sintering process, the drive motor 25 is turned on, and the drive motor 25 drives the rotating shaft 41 to rotate, so that the impeller 24 rotates slowly. The slow rotation of the impeller 24 accelerates the air flow rate inside the mounting shell 21, so that the flue gas slowly enters the guide pipe 22 along the exhaust pipe 13, and then enters the heat exchange coil 33. The heat carried by the flue gas entering the heat exchange coil 33 will be absorbed by the heat exchange coil 33, and the heat exchange coil 33 will transfer the heat The water in the water storage chamber 32 is heated to increase the temperature inside the preheating box 31. By increasing the temperature inside the preheating box 31, the resistor green sheets on the carrier network 35 can be preheated. After the last batch of resistor green sheets are sintered, the sintered resistor green sheets are taken out, and then the preheated resistor green sheets inside the preheating box 31 are taken out and placed inside the sintering device body 1 for sintering. By heating the water inside the water storage chamber 32, waste heat recovery and reuse are achieved. At the same time, by preheating the resistor green sheets, the heat required for the sintering process of the preheated resistor green sheets can be reduced, thereby further reducing the energy consumption during the sintering process. In addition, the phenomenon of uneven heating of the resistor green sheets due to sudden temperature rise during the sintering process can be significantly reduced, thereby reducing the problems of stress concentration and structural defects inside the resistor green sheets and improving the sintering quality of the resistor green sheets.

[0038] Reference Figure 2 and Figure 3 The rapping member 4 includes a plurality of rotating shafts 41 rotatably connected to the interior of the preheating box 31 , and a rapping cam 42 is fixed on the rotating shaft 41 .

[0039] A pulley 43 is fixed to the end of the driving shaft 23 and the end of one of the rotating shafts 41 , and the two pulleys 43 are connected to each other via a transmission belt 44 .

[0040] Furthermore, one end of the rotating shaft 41 extends out of the preheating box 31 and is fixed with a transmission gear 45 , and two adjacent transmission gears 45 are meshed with each other.

[0041] When the driving shaft 23 drives the impeller 24 to rotate, the driving shaft 23 drives the pulley 43 fixed at its end to rotate, and then the pulley 43 at the end of one of the rotating shafts 41 is rotated under the action of the transmission belt 44, so that one of the rotating shafts 41 rotates, and then all the rotating shafts 41 are able to rotate under the action of the transmission gear 45. When the rotating shaft 41 rotates, the rapping cam 42 follows the rotation. As the rapping cam 42 continues to rotate, the carrying net 35 will be vibrated. When the carrying net 35 is vibrated, the resistor green sheets placed on its surface are vibrated, so that the resistor green sheets are fully in contact with the hot air inside the preheating box 31, thereby improving the preheating uniformity and preheating effect of the resistor green sheets.

[0042] When the resistor green body is preheated using the preheating box 31, the green body is in a low-temperature preheating stage at this time, and the temperature is lower than the volatilization temperature of the binder. Although the green body after being pressed contains a binder, it still maintains a solid structure at the preheating temperature. During the vibration process of the vibration cam 42, the vibration intensity is a low-frequency micro-vibration rather than a strong impact, which loosens the micro-particles on the surface of the green body through low-frequency micro-loosening; and the vibration causes the resistor green body to slightly displace to avoid adhesion to the supporting mesh 35, ensuring that the hot air flow is evenly wrapped. Moderate vibration can release the internal stress generated by pressing and reduce the risk of cracks in subsequent sintering.

[0043] A sintering process for producing a varistor comprises the following steps: S1: When loading the resistor green body on the heating plate, the spacing is controlled to be 15±2mm, and then the sintering chamber protective door 14 is opened to place the sintering plate into the sintering device body 1; S2: Check the air circuit sealing before starting and ensure the nitrogen reserve is greater than 50m³; S3: During the heating stage, the temperature is raised to 600°C at a rate of 5°C / min and kept at this temperature for 30 minutes to remove the binder; S4: During the sintering stage, the temperature is maintained at 1150±5℃ and the oxygen concentration is controlled within the range of ±3% of the set value; S5: During the cooling phase, the oxygen supply is turned off and the temperature is lowered to 200°C at a rate of 10°C / min before being taken out of the furnace; S6: During sintering, the next batch of resistor green sheets to be sintered are placed on the carrier mesh 35. During the sintering process, the heat in the flue gas is used to preheat the resistor green sheets. S7: After sintering is completed, the preheated resistor green compacts are taken out and the above steps S1 to S6 are repeated until all batches of resistor green compacts are sintered.

[0044] Working principle: Load resistor green sheets on the heating plate, then open the sintering chamber protective door 14 and place the sintering plate into the sintering device body 1, place the next batch of resistor green sheets to be sintered on the carrier net 35, then insert the carrier net 35 into the preheating box 31, so that the frame of the carrier net 35 fits with the support bar 36, and then the mounting plate 34 is fixed to the surface of the preheating box 31 under the action of the first magnet and the second magnet, and then place resistor green sheets on the surface of multiple carrier nets 35 in turn and connect them to the preheating box 31. Check the air path sealing before starting, and then start sintering. Maintain and control the sintering temperature and oxygen concentration during the sintering stage; Before sintering, the drive motor 25 is turned on. The drive motor 25 drives the rotating shaft 41 to rotate, so that the impeller 24 rotates slowly. The slow rotation of the impeller 24 accelerates the air flow rate inside the installation shell 21, so that the smoke slowly enters the guide pipe 22 along the exhaust pipe 13, and then enters the heat exchange coil 33. The heat carried by the smoke entering the heat exchange coil 33 will be absorbed by the heat exchange coil 33, and the heat exchange coil 33 will transfer the heat to the water inside the water storage chamber 32 to heat the water, thereby increasing the temperature inside the preheating box 31. By increasing the temperature inside the preheating box 31, the resistor green body on the carrier network 35 can be heated. Preheating is performed to realize the recovery and reuse of waste heat in the flue gas. At the same time, when the driving shaft 23 drives the impeller 24 to rotate, the driving shaft 23 drives the pulley 43 fixed at its end to rotate, and then the pulley 43 at the end of one of the rotating shafts 41 is rotated under the action of the transmission belt 44, so that one of the rotating shafts 41 rotates, and then all the rotating shafts 41 are able to rotate under the action of the transmission gear 45. When the rotating shaft 41 rotates, the rapping cam 42 rotates accordingly. As the rapping cam 42 continues to rotate, the carrier net 35 is rapped at a low frequency, so that the resistor green body is fully in contact with the hot air inside the preheating box 31; When cooling after sintering, turn off the oxygen supply, cool to 200°C and then take out of the furnace. Then take out the preheated resistor green sheets in the preheating box 31 and put them into the sintering device body 1 for sintering. Repeat the above operation until all batches of resistor green sheets are sintered.

Claims

1. A high-performance oxygen-enriched sintering device for producing varistor, comprising a sintering device body (1), characterized in that: A base (11) is fixed to the lower end of the sintering device body (1), a smoke exhaust port is provided at the upper end of the sintering device body (1), a filter box (12) is fixed at the position of the smoke exhaust port provided at the upper end of the sintering device body (1), a smoke exhaust pipe (13) is fixed to the upper end of the filter box (12), a sintering chamber protection door (14) is installed on the side of the sintering device body (1), a controller (15) is fixed on the side of the sintering device body (1), and a waste heat recovery structure (2) for recovering and reusing waste heat from flue gas is provided on the sintering device.

2. The high-performance oxygen-enriched sintering device for varistor production according to claim 1, characterized in that: The waste heat recovery structure (2) includes a mounting shell (21) fixed to one end of the exhaust pipe (13) away from the filter box (12), a guide tube (22) is fixed to the end of the mounting shell (21) away from the exhaust pipe (13), a drive shaft (23) is rotatably connected inside the mounting shell (21), an impeller (24) is fixed on the drive shaft (23), a drive motor (25) is fixed to the upper end of the sintering device body (1), the drive motor (25) is electrically connected to the controller (15), one end of the drive shaft (23) passes through the mounting shell (21) and is fixedly connected to the output end of the drive motor (25), and a waste heat recycling component (3) is provided on the side of the sintering device body (1).

3. The high-performance oxygen-enriched sintering device for varistor production according to claim 2, characterized in that: The waste heat recycling component (3) comprises a preheating box (31) fixed to the end of the sintering device body (1), a water storage chamber (32) is provided inside the preheating box (31), and the water storage chamber (32) is used to accommodate a water medium. A water supply pipe connected to the water storage chamber (32) is fixed to the upper end of the preheating box (31), and a drainage pipe connected to the water storage chamber (32) is fixed to the lower end of the preheating box (31). A heat exchange coil (33) is fixed to the end of the guide pipe (22) away from the mounting shell (21), and the heat exchange coil (33) is located inside the water storage chamber (32). The heat exchange coil (33) is a copper tube. A rapping member (4) is provided inside the preheating box (31).

4. The high-performance oxygen-enriched sintering device for varistor production according to claim 3, characterized in that: A plurality of mounting plates (34) are mounted on the side of the preheating box (31), a supporting net (35) is fixed on the side of the mounting plate (34), the supporting net (35) is slidably inserted into the interior of the preheating box (31), a supporting bar (36) is fixed inside the preheating box (31), and a frame of the supporting net (35) is in contact with the supporting bar (36).

5. The high-performance oxygen-enriched sintering device for varistor production according to claim 4, characterized in that: A first magnetic strip (37) is fixed to the side of the mounting plate (34), and a second magnetic strip (38) that attracts the first magnetic strip (37) is provided on the side of the preheating box (31).

6. The high-performance oxygen-enriched sintering device for varistor production according to claim 3, characterized in that: The rapping member (4) comprises a plurality of rotating shafts (41) rotatably connected to the interior of the preheating box (31), and a rapping cam (42) is fixed to the rotating shafts (41).

7. The high-performance oxygen-enriched sintering device for varistor production according to claim 6, characterized in that: A pulley (43) is fixed to the end of the driving shaft (23) and the end of one of the rotating shafts (41), and the two pulleys (43) are connected to each other via a transmission belt (44).

8. The high-performance oxygen-enriched sintering device for varistor production according to claim 6, characterized in that: One end of the rotating shaft (41) extends out of the preheating box (31) and is fixed with a transmission gear (45), and two adjacent transmission gears (45) are meshed with each other.

9. A sintering process for producing a varistor, characterized by: A high-performance oxygen-enriched sintering device for producing a varistor according to any one of claims 1 to 9 is used, characterized in that it comprises the following steps: S1: When loading the resistor green body on the heating plate, the spacing is controlled to be 15±2 mm, and then the sintering chamber protection door (14) is opened to place the sintering plate into the sintering device body (1); S2: Check the air circuit sealing before starting and ensure the nitrogen reserve is greater than 50m³; S3: During the heating stage, the temperature is raised to 600°C at a rate of 5°C / min and kept at this temperature for 30 minutes to remove the binder; S4: During the sintering stage, the temperature is maintained at 1150±5℃ and the oxygen concentration is controlled within the range of ±3% of the set value; S5: During the cooling phase, the oxygen supply is turned off and the temperature is lowered to 200°C at a rate of 10°C / min before being taken out of the furnace; S6: During sintering, the next batch of resistor green sheets to be sintered are placed on the carrier mesh (35), and the heat in the flue gas is used to preheat the resistor green sheets during the sintering process; S7: After sintering is completed, the preheated resistor green compacts are taken out and the above steps S1 to S6 are repeated until all batches of resistor green compacts are sintered.

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