TECHNICAL FIELD

[0001] The present application relates to a sintering furnace and, more particularly, to a sintering furnace for manufacturing solar cell photovoltaic devices.

BACKGROUND

[0002] A sintering furnace is needed to perform sintering processing of photovoltaic devices in the production of photovoltaic devices such as crystalline silicon solar cell wafers. The sintering furnace comprises at least a sintering section and a cooling section. Photovoltaic devices are conveyed through the sintering section and the cooling section in sequence and are then transported out of the sintering furnace via a conveyor belt. Photovoltaic devices reach a certain performance level by high-temperate sintering in the sintering section and then cooling in the cooling section. The cooling section can reduce the temperature of the photovoltaic devices by a certain range.

SUMMARY

[0003] The present application provides a sintering furnace, comprising: a heating chamber, wherein sintered elements are configured to be heated in the heating chamber; a cooling chamber, wherein sintered elements conveyed to the cooling chamber from the heating chamber are cooled in the cooling chamber; a conveyor, wherein the conveyor is configured to convey sintered elements through the heating chamber and the cooling chamber; a cooling system, wherein the cooling system is configured to cool sintered elements in the cooling chamber and comprises at least one heat exchanger and at least one first fan, said at least one heat exchanger and said at least one first fan being located above the conveyor, and said at least one first fan being arranged near said at least one heat exchanger and being configured to guide air to flow through said at least one heat exchanger.

[0004] In the above-mentioned sintering furnace, the cooling chamber comprises at least two cooling areas arranged in sequence in the conveying direction of the conveyor, said at least two cooling areas being interconnected.

[0005] In the above-mentioned sintering furnace, the first fan is configured to guide air, which has undergone heat exchange in said at least one heat exchanger, to flow in opposite to the conveying direction of the conveyor; wherein a heat exchanger and a first fan are provided in each of cooling areas except the most downstream cooling area in the conveying direction of the conveyor, the heat exchanger in each cooling area being configured to be close to a cooling area downstream of the corresponding cooling area.

[0006] In the above-mentioned sintering furnace, the cooling system further comprises a plurality of second fans, the plurality of second fans being arranged in the conveying direction of the conveyor, wherein, in a height direction of the cooling chamber, the plurality of second fans are provided between the conveyor and said at least one heat exchanger and are configured to guide air, which has undergone heat exchange in said at least one heat exchanger, to flow towards sintered elements on the conveyor.

[0007] In the above-mentioned sintering furnace, the cooling system further comprises a blower, the blower being an exhaust blower, the blower having an exhaust end and a suction end, the suction end of the blower being connected to the interior of the cooling chamber, and the exhaust end of the blower being connected to the external environment to guide air in the interior of the cooling chamber to flow towards the exterior of the cooling chamber.

[0008] In the above-mentioned sintering furnace, the cooling system further comprises an air duct, the air duct having at least one air duct inlet and an air duct outlet, said at least one air duct inlet being provided below the conveyor, and the air duct outlet being connected to the suction end of the blower.

[0009] In the above-mentioned sintering furnace, the cooling system further comprises a lower guide hood, the lower guide hood covering the bottom of the conveyor and having at least one lower guide hood outlet, and said at least one lower guide hood outlet being connected to said at least one air duct inlet.

[0010] In the above-mentioned sintering furnace, the cooling system further comprises an upper guide hood, the upper guide hood being connected to the upper part of the conveyor, a plurality of mounting holes being provided in the upper guide hood, and the plurality of mounting holes being used to install the plurality of second fans.

[0011] In the above-mentioned sintering furnace, the heat exchanger is a water-cooled finned tubular heat exchanger. [0012] In the above-mentioned sintering furnace, the first fan is a filtration fan and the blower is a high temperature insulation centrifugal blower.

[0013] The sintering furnace in the present application has an exhaust assembly and a heat exchanger located the upper part of the cooling chamber. The air in the cooling chamber in the present application can be exchanged with the air in the external environment. The cooled air in the cooling chamber can flow from top down through the sintered elements to be cooled. The sintering furnace in the present application has a small cooling efficiency, and the cooling chamber has a small length.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Fig. 1 is a schematic of a sintering furnace in the present application.

[0015] Fig. 2A is a 3D diagram of the cooling section and rear section of the sintering furnace shown in Fig. 1.

[0016] Fig. 2B is a 3D diagram of that shown in Fig. 2A, with the cooling section of the cooling section shell and the rear section removed.

[0017] Fig. 2C is a side view of that shown in Fig. 2B, with the cooling section of the cooling section shell and the rear section removed.

[0018] Fig. 3 A is a 3D diagram of the heat exchanger assemblies shown in Fig. 2B.

[0019] Fig. 3B is an exploded view of the heat exchanger assemblies shown in Fig. 3A.

[0020] Fig. 4A is a 3D diagram of the exhaust assembly shown in Fig. 2B.

[0021] Fig. 4B is an exploded view of the exhaust assembly shown in Fig. 4A.

[0022] Fig. 5 is a 3D diagram of the conveyor and the second fan assembly.

[0023] Fig. 6 is a schematic of the airflow direction in the cooling section shown in Fig. 1.

DETAIFED DESCRIPTION

[0024] Various particular embodiments of the present invention will be described below by referring to the accompanying drawings which are a part of the description. It should be understood that although directional terms such as "front", "rear", "upper", "lower", "left" and "right" are used to describe structural parts and elements of various examples in the present application, their use here is for the description purpose only and is determined based on the example directions shown in the accompanying drawings. Because the embodiments disclosed in the present application can be set in different directions, these directional terms are only descriptive and should not be deemed a limitation. Where possible, the same or similar accompanying drawing reference signs used in the present application refer to the same components.

[0025] Fig. 1 is a schematic of a sintering furnace 100 in the present application, showing the basic structure of the sintering furnace. As shown in Fig. 1, the sintering furnace 100 comprises a sintering section 101, a cooling section 102 and a conveyor 120 which runs through the sintering section 101 and the cooling section 102. Sintered elements to be processed is conveyed by the conveyor 120 to finish sintering processing through the sintering section 101 and the cooling section 102 in sequence in the direction shown by the arrow 108. The sintering section 101 has a heating chamber where photovoltaic devices are heated to a certain temperature range such as 700°C-900°C to achieve high temperature sintering processing of sinter elements. After sintering processing, sintered elements enter the cooling section 102, the cooling section 102 can cool the sintered elements a certain temperature range such as below 60°C. The cooled sintered elements are conveyed out of the sintering furnace by the conveyor 120. The sintering furnace 100 further comprises a front section 111 and a rear section 112. The front section 111 is provided upstream of the sintering section 101, and the rear section 112 is provided downstream of the cooling section 102. The front section 111 and the rear section 112 are used to accommodate the power device and other devices of the conveyor 120. The sintering furnace 100 has a length direction L, a height direction H and a width direction W (Refer to Fig. 2A).

[0026] Fig. 2A is a 3D diagram of the cooling section 102 and the rear section 112 of the sintering furnace 100 shown in Fig. 1. Fig. 2B is a 3D diagram of that shown in Fig. 2A, with the cooling section 102 of the cooling section shell and the rear section 112 removed. Fig. 2C is a side view of that shown in Fig. 2B, with the cooling section 102 of the cooling section shell and the rear section 112 removed. Figs. 2A-2C show the structure of the cooling section 102.

[0027] As shown in Figs. 2A-2C, the cooling section 102 has a cooling section shell 201 and a support 209, and the cooling section shell 201 is installed on the support 209. The cooling section shell 201 forms a cooling chamber 207. The cooling section shell 201 is roughly a box which has an opening in the lower part. The cooling section shell 201 comprises a front plate 231, a rear plate 232, an upper plate 233, a left plate 234 and a right plate 235. The left side of the cooling section shell 201 is connected to the sintering section 101, and the right side is connected to the rear section 112. The support 209 is roughly a cubic frame structure. The support 209 comprises a support bottom 291, a support top 292 and a plurality of support pillars 293. Each of the plurality of pillars 293 is arranged in the vertical direction, and the two ends are connected to the support top 292 and the support bottom 291, respectively.

[0028] The cooling section 102 has some support legs 263. The support legs 263 are connected to the support bottom 291. The support legs 263 have a certain height to achieve a certain distance between the lower opening and the ground so that the lower opening can be externally connected. The support legs 263 have a small height so that the gap between the lower opening and the ground is small. Only a small amount of air in the cooling chamber 207 can be exchanged with the external air through this gap. Openings 261 and 262 are provided in the left plate 234 and right plate 235 of the cooling section shell 201 to allow the conveyor 120 and photovoltaic devices conveyed by the conveyor 120 to pass through. The opening 262 is located in the middle part of the cooling section 102 in the height direction and adjoins the rear section 112. The conveyor 120 and the conveyed sintered elements are located in the middle part of the cooling section 102.

[0029] The conveyor 120 comprises a support part 230 and a conveyor belt positioned above the support part 230 (not shown in the figures). The conveyor belt is supported by the support part 230 and moves with respect to the support part 230 to move the sintered elements.

[0030] The cooling chamber 207 comprises a first cooling area 271 , a second cooling area 272 and a third cooling area 273 arranged in sequence. The first cooling area 271, the second cooling area 272 and the third cooling area 273 are interconnected.

[0031] A cooling system is provided in the cooling chamber 207 to cool sintered elements. The cooling system comprises three exhaust assemblies 240, two heat exchanger assemblies 250 and a second fan assembly 260. The second fan assembly 260 is located above the conveyor 120 and connected to the conveyor 120. The second fan assembly 260 extends to the tail end of the third cooling area 273 from the front end of the first cooling area 271 in the conveying direction. Each of the three exhaust assemblies 240 has the same or similar structure and is respectively provided in the first cooling area 271, the second cooling area 272 and the third cooling area 273. Each of the two heat exchanger assemblies 250 has the same or similar structure and is respectively provided between the first cooling area 271 and the second cooling area 272 and between the second cooling area 272 and the third cooling area 273. Each of the two heat exchanger assemblies 250 is connected to the support 209 and located above the second fan assembly 260.

[0032] Fig. 3 A is a 3D diagram of the heat exchanger assemblies 250 shown in Fig. 2B. Fig. 3B is an exploded view of the heat exchanger assemblies 250 shown in Fig. 3 A. Figs. 3 A and 3B show the structure of the heat exchanger assemblies 250. As shown in Figs. 3 A and 3B, the heat exchanger assemblies 250 comprise a heat exchanger 301 and a first fan assembly 302. The first fan assembly 302 comprises first fans 303 and 304 and a first fan support 305. The first fans 303 and 304 are installed on the first fan support 305 side by side. The first fan assembly 302 is connected to the heat exchanger 301 via the first fan support 305. In the present application, the heat exchanger 301 is a water-cooled finned tubular heat exchanger. The heat exchanger 301 is roughly platelike and has a front side 311 and a back side 312. The heat exchanger 301 has a plurality of fins and heat exchange tubes arranged side by side (not shown in the figures). The fins are arranged in the direction perpendicular to the front side 311 and the back side 312. The heat exchange tubes pass through a plurality of fins. There is a gap between two adjacent fins so that air can flow through the heat exchanger 301 in the direction from the front side 311 to the back side 312 or from the back side 312 to the front side 311.

[0033] The heat exchanger 301 has a cooling medium outlet and a cooling medium inlet which are respectively connected to the heat exchange tubes. The cooling medium (such as cooling water) enters the heat exchange tubes from the cooling medium inlet and flows out of the cooling medium outlet. The temperature of air in the cooling chamber 207 is higher than that of the cooling medium. The air in the cooling chamber 207 exchanges heat with the cooling medium flowing in the heat exchange tubes via the fins and heat exchange tubes to lower the temperature of the air in the cooling chamber 207.

[0034] In an embodiment of the present application, the first fans 303 and 304 are filtration fans, and the first fans 303 and 304 comprise a filtering layer on the outlet side of the fans (not shown in the figures). The filtering layer can filter impurities in the air to decrease the reduction in the heat exchange efficiency of the heat exchanger due to impurity accumulation on the surface of the heat exchanger. The filtering layer can also reduce impurities in the cooling chamber to avoid the effect of impurities on the performance of sintered elements. In an embodiment of the present application, the dimensions of the heat exchanger 301 are 826 * 406 * 111 mm, and the power range of the first fans 303 and 304 is: 50-70 W. In an embodiment, the power range of the first fans 303 and 304 is 65 W.

[0035] Fig. 4A is a 3D diagram of the exhaust assembly 240 shown in Fig. 2B. Fig. 4B is an exploded view of the exhaust assembly 240 shown in Fig. 4A. Figs. 4A and 4B show the structure of the exhaust assembly 240.

[0036] As shown in Figs. 4A and 4B, the exhaust assembly 240 comprises a blower 401, an air duct 402 and a lower guide hood 403. The blower 401 is connected to the support top 292 of the support 209 and located in the cooling chamber 207. The blower 401 has a suction end 461 and an exhaust end 462. The suction end 461 is connected to the air duct 402. The exhaust end 462 is connected to the exhaust device of the building via a vent on the cooling section shell 201 so that the exhaust end 462 can communicate with the external environment. In an embodiment of the present application, the blower 401 is a high-temperature insulation centrifugal blower.

[0037] The air duct 402 comprises three air duct inlets 411, 412 and 413 and an air duct outlet 415. The air duct outlet 415 is connected to the suction end 461 of the blower 401. The air duct inlets 411, 412 and 413 are connected to the lower guide hood 403. The air duct 402 comprises a main pipe 416, a first branch pipe 417, a second pipe 418, and a four-way connector 419. One end of the main pipe 416 forms the air duct outlet 415 and the other end is connected to the first connection of the four- way connector 419. One end of the first branch pipe 417 and that of the second first branch pipe 418 each forms air duct inlets 411 and 413 respectively, and the other end is connected to the second connection and third connection of the four-way connector 419. The fourth connection of the four- way connector 419 forms the air duct inlet 411. The blower 401 connected to the air duct 402 provides power to guide air to flow towards the air duct outlet 415 from the air duct inlets 411, 412 and 413.

[0038] The lower guide hood 403 has a bottom 431 , a pair of oppositely positioned length side walls 432 and 433 and a pair of oppositely positioned width side walls 434 and 435. The pair of oppositely positioned length side walls 432 and 433 and the pair of oppositely positioned width side walls 434 and 435 extends upwards from the edge of the bottom 431 and are interconnected to form a box which has an opening at the top. A lower guide space 446 is formed in the lower guide hood 403. The tops of the pair of length side walls 432 and 433 and the pair of width side walls 434 form an upper guide hood opening 438. The upper guide hood opening 438 forms an upper guide hood inlet. The lower guide hood 403 further comprises a pair of folding edges 441 and 442 formed by horizontally and outwardly extending the tops of the pair of length side walls 432 and 433 respectively. The pair of folding edges 441 and 442 are used to connect to the bottom of the conveyor 120. The bottom 431 has three uniformly arranged mounting holes 451, 452 and 453. The mounting holes 451, 452 and 453 respectively form three lower guide hood outlets. The shapes of the mounting holes 451, 452 and 453 matches those of the air duct inlets 411, 412 and 413, respectively, so that the ends of the air ducts 402 at the air duct inlets 411, 412 and 413 can be installed in the mounting holes 451, 452 and 453 to allow the internal space of the air duct 402 to communicate with the lower guide space 446.

[0039] Fig. 5 is a 3D diagram of the conveyor 120 and the second fan assembly 260. As shown in Fig. 5, the conveyor 120 comprises a support part 501 and a conveyor belt located over the support part 501 (not shown in the figures). The conveyor belt can be driven by the power device to move with respect to the support part 501. Sintered elements to be conveyed are placed on the conveyor belt and move together with the conveyor belt in the conveying direction.

[0040] The second fan assembly 260 comprises an upper guide hood 503 and a plurality of second fans 509. The upper guide hood 503 is connected to the upper part of the conveyor 120. The upper guide hood 503 is roughly of long strip shape and extends in the extended direction of the conveyor 120. The upper guide hood 503 comprises a top 511 and a pair of side parts 512 and 513 which extend outwards and downwards on two sides in the length direction of the top 511. In other words, the upper guide hood 503 has a shape of being high in the middle and low in two sides, i.e., the cross section of the upper guide hood 503 is roughly a trapezoid. An upper guide space 546 is formed in the upper guide hood 503. A plurality of mounting holes are provided on the top 511 to install a plurality of second fans 509. The plurality of second fans 509 are arranged side by side in the length direction of the upper guide hood 503. The plurality of second fans 509 guide the air above the plurality of second fans 509 to go into the upper guide space 546. In an embodiment of the present application, the power range of the plurality of second fans 509 is: around 25 W. The bottom of the side part 512 of the upper guide hood 503 is pivotally connected to the conveyor 120. A handle is provided on the side part 513. Operators may hold the handle to rotate the second fan assembly 260 to expose the conveyor 120 to facilitate maintenance and cleaning of the conveyor 120. [0041] The width of the conveyor 130 accounts for more than a half of that of the cooling chamber 207. The width of the upper guide hood 503 and the lower guide hood 403 matches that of the conveyor 130. When the second fan assembly 260 and the exhaust assembly 240 are properly installed in the sintering furnace 100, the upper guide hood 503 covers the upper part of the conveyor 130, and the lower guide hood 403 covers the lower part of the conveyor 130. The gap between the upper guide hood 503 and the lower guide hood 403 and the side wall of the cooling section shell 201 is small. Only a small amount of air above the upper guide hood 503 can pass through the gap to enter the space below the lower guide hood 403.

[0042] Fig. 6 is a schematic of the air flow direction in the cooling section shown in Fig. 1. As shown in Fig. 6, the conveyor 130 is divided into an upper space 601 and a lower space 602. The heat exchange assemblies 250 and the blower 401 are located in the upper space 601. The three air duct inlets 411, 412 and 413 of the air duct 402 are located in the lower space 602, and the air duct outlet 415 of the air duct 402 is located in the upper space 601. The heat exchange assemblies 250 can exchange heat with the air in the cooling chamber 207 to lower the temperature of the air in the cooling chamber 207. From the upper space 601, the air cooled by the heat exchange assemblies 250 comes to the cooling chamber after successively flowing through the upper guide space 546, the conveyor 130, the lower guide space 446 and the air duct 402. The air cooled by the heat exchange assemblies 250 cools the sintered elements on the conveyor 130 to lower the temperature of the sintered elements.

[0043] As shown in Fig. 6, two heat exchanger assemblies 250a and 250b are provided in the cooling chamber 207, and the heat exchanger assemblies 250a and 250b have the same structure. The heat exchange assembly 250 shown in Figs. 3A and 3B is either of the heat exchanger assemblies 250a and 250b shown in Fig. 6. The heat exchanger assembly 250a is located between the first cooling area 271 and the second cooling area 272 and is arranged near the top of the cooling chamber 207. There is a gap between the heat exchanger assembly 250a and the second fan assembly 260 to provide a certain operation space above the second fan assembly 260 to allow operators to upwardly open the second fan assembly 260 for maintenance and servicing.

[0044] In the conveying direction of the conveyor, the respective heat exchanger 301 of the heat exchanger assemblies 250a and 250b is respectively provided upstream of the corresponding first fan assembly 302. The first fan 303 provides the heat exchanger 301 with an air flow upstream in the conveying direction. The cooler air in the cooling chamber 207 that has undergone heat exchange through the heat exchanger assembly 250a flows towards the left plate 234 of the cooling section shell 201 until it changes its direction when it is blocked by the left plate 234. The air flow continues to move downwards in a direction away from the left plate 234. Most of the air flow which moves downwards is blocked by the conveyor and the second fan assembly 260 and then changes its direction and continues to move in a direction away from from the left plate 234. Similarly, the cooler air flow in the cooling chamber 207 that has undergone heat exchange through the heat exchanger assembly 250b flows towards the left plate 234 of the cooling section shell 201 until it changes its direction when it is blocked by the heat exchanger assembly 250a or the left plate 234. The air flow continues to move downwards in a direction away from from the left plate 234. Most of the airflow which moves downwards is blocked by the conveyor and the second fan assembly 260 and then changes its direction and continues to move in a direction away from the left plate 234. The air flowing in the conveying direction after passing through the heat exchanger assemblies 250a and 250b moves to the right in the conveying direction until it changes its direction when it is blocked by the right plate 235. The air flow continues to move upwards until it changes its when it is blocked by the upper plate 233. The air flow continues to move towards the left plate 234. Therefore, the air in the upper space 601 in the cooling chamber 207 can circulate in the clockwise direction as shown by the arrow 640 so that the air in the upper space 601 is evenly distributed and has a lower temperature. In the rear section of the cooling chamber, i.e., in the third cooling area 273, the sintered elements have already reduced in temperature after being cooled in the first cooling area and the second cooling area, so a heat exchanger assembly 250 may not be provided in the third cooling area 273. The cooling capacity of the heat exchanger assemblies 250a and 250b has been able to meet the temperature requirements of the sintered elements in the third cooling area 273.

[0045] The second fan assembly 260 provides a downward air flow and guides the air flow in the upper space 601 that has undergone heat exchange to successively flow down the upper guide space, the conveyor and the lower guide space to exchange heat with the conveyed sintered elements on the conveyor to reduce the temperature of the sintered elements. The high-temperature air which has undergone heat exchange with the sintered elements enters the air duct 402 of the exhaust assembly 240 from the lower guide space in the direction shown in the arrow 650 and is let out of the cooling chamber 207. The exhaust assembly 240 provides power for the flowing of the air flow in the air duct 402 to facilitate the air flow to be quickly moved out of the cooling chamber 207. The lower opening of the cooling chamber 207 is connected to the outside to replenish air in the cooling chamber 207 to maintain air pressure balance in the cooling chamber 207.

[0046] In the present application, the conveyor divides the cooling chamber into an upper space 601 and a lower space 602. There is only a small connection area between the upper space 601 and the lower space 602. Therefore, most of the air in the upper space 601 circulates in the upper space 601 under the guide of the first fan 303, and only a small amount of air enters the lower space 602 through the gap between the conveyor and the cooling section shell 201. The cooled air in the upper space 601 is guided to the sintered elements by the second fan assembly 260 to cool the sintered elements. The cooled air is effectively used.

[0047] In the present application, an exhaust assembly is provided so that the air in the cooling chamber can be exchanged with the outside air and that the high-temperature air can be quickly discharged to the outside, facilitating the reduction in the temperature in the cooling chamber. The heat exchanger assemblies in the present application are provided above the conveyor. After heat exchange and temperature reduction by the heat exchangers, the air in the upper space of the cooling chamber is guided to the sintered elements to be cooled so that the cooled air in the cooling chamber can quickly arrive at the sintered elements. Compared with a cooling chamber of a sintering furnace with heat exchanger assemblies being provided at the bottom of the conveyor, the cooling chamber in the present application avoid the accumulation of cooled air at the bottom of the cooling chamber, i.e., below the conveyor, causing the waste of cooled air. In addition, the heat exchanger assemblies in the present application comprise a fan which drive the air flow in the upper space of the cooling chamber to achieve uniform distribution of the cooled air in the upper space of the cooling chamber so that the cooled air flowing towards the sintered elements is uniform. Furthermore, the cooled air in the cooling chamber in the present application circulates in the upper space of the cooling chamber, so a heat exchanger assembly may not be provided in the last cooling area downstream in the conveying direction. Compared with a cooling chamber of a traditional sintering furnace with the same length, the cooling efficiency of the cooling chamber in the present application can increase by 40%-60%. In an embodiment of the present application, the cooling efficiency of the cooling chamber can increase by 50%. [0048] The cooling section in the present application has a high efficiency, so the time required to cool the sintered elements to a predetermined temperature at a given conveying speed of the conveyor is short and the required length of the cooling section is short, facilitating a reduction in the overall dimensions of the sintering furnace.

[0049] Although only some features are illustrated and described herein, those skilled in the art may make various improvements and changes. It should be understood that the purpose of the attached claims is to cover all the above-mentioned improvements and changes which fall within the spirit and scope of the present application.