Gas backflow prevention device for boron diffusion processing of photovoltaic cell

Abstract

A gas backflow prevention device for boron diffusion processing of a photovoltaic cell relates to the field of photovoltaic cell panel processing, and comprises a furnace tube and a nitrogen pneumatic valve, the nitrogen pneumatic valve is arranged on the furnace tube, an input end of the nitrogen pneumatic valve is provided with a backflow prevention mechanism, and the backflow prevention mechanism is used for preventing mixed gas of boron trichloride and nitrogen from flowing back. The backflow prevention mechanism comprises a valve body and a non-return assembly, and the valve body is connected with the input end of the nitrogen pneumatic valve. An anti-backflow mechanism is additionally arranged in the position, in front of the nitrogen pneumatic valve, of each furnace tube, a non-return step locking structure is adopted in each anti-backflow mechanism, when boron trichloride gas normally passes through, a non-return assembly is folded and contracted, the gas blocking condition cannot be generated, and when the nitrogen pneumatic valve is abnormal and nitrogen backflow is caused, the nitrogen backflow is prevented. When the nitrogen pneumatic valve is abnormal, the nitrogen pressure blows the non-return assembly to unfold reversely, the non-return disc is attached to the non-return step, the backflow blocking effect of airflow is achieved, and the problems of high cost and troubleshooting difficulty caused by abnormity of the nitrogen pneumatic valve are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cell panel processing, and particularly to an anti-gas backflow device for boron diffusion processing of photovoltaic cells. Background Art

[0002] During the processing of the PN junction of photovoltaic cell panels, the boron diffusion process is mostly adopted. Boron diffusion is a high-temperature heating method. Under low-pressure conditions, boron trichloride is introduced. Boron trichloride changes from a liquid state to a gaseous state at 45 - 55°C, reacts with oxygen to form boron oxide and deposits on the surface of the silicon wafer, thereby forming the "heart" PN junction of the photovoltaic cell. In current boron diffusion equipment, the poor quality of individual nitrogen pneumatic valves causes nitrogen to flow back into the main pipeline. Moreover, since the current boron trichloride supply for boron diffusion adopts a one-to-four or centralized supply method, the backflow of nitrogen in one pipe causes the concentration of the entire bottle of boron trichloride gas to be abnormal, and at the same time, it causes the sheet resistance of 24 pipes in 4 machines (one-to-four supply means: 1 boron trichloride cylinder can supply 4 processing devices, and one processing device has 6 furnace tubes, with a total of 24 furnace tubes) to be abnormal, resulting in batch rework due to defective products.

[0003] The boron trichloride gas pipeline for boron diffusion enters the furnace tube through a flow meter and a nitrogen pneumatic valve. After the gas supply process ends and the nitrogen purging process is carried out, the excessive nitrogen pressure causes nitrogen to rush into the main pipeline of boron trichloride along the furnace pipeline, and finally nitrogen flows back against the current into the boron trichloride storage tank, resulting in an abnormal transmission concentration of boron trichloride and batch rework. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0005] For this reason, the purpose of the present invention is to provide an anti-gas backflow device for boron diffusion processing of photovoltaic cells, which realizes the function of blocking the backflow of air, avoids a large number of reworks caused by nitrogen backflow, and effectively reduces the problems of high cost and difficult troubleshooting caused by abnormal nitrogen pneumatic valves.

[0006] To achieve the above object, the present invention provides an anti-gas-backflow device for boron diffusion processing of photovoltaic cells, including a furnace tube and a nitrogen pneumatic valve. The nitrogen pneumatic valve is arranged on the furnace tube. It is characterized in that an anti-backflow mechanism is arranged at the input end of the nitrogen pneumatic valve. The anti-backflow mechanism is used to prevent the mixed gas of boron trichloride and nitrogen from flowing back. The anti-backflow mechanism includes a valve body and a check component. Among them, the valve body is connected to the input end of the nitrogen pneumatic valve, the check component is arranged inside the valve body, a check step is arranged inside the valve body, the outlet side diameter of the check step is larger than the inlet side diameter, the check component is arranged on the outlet side of the check step, and the check component includes a check disk and folding ribs. Among them, the check disk is arranged on the outlet side of the check step, multiple folding ribs are arranged, and the multiple folding ribs are radially arranged inside the check disk, and the radial center positions of the multiple folding ribs are pivotally connected.

[0007] Further, a connecting rod component is arranged on the inlet side of the check step. The connecting rod component is used to restrain the check component. The connecting rod component includes a connecting rod. Among them, the connecting rod is horizontally arranged on the inlet side of the check step, a sliding rod is arranged at the end of the connecting rod, the middle position of the check disk is slidably arranged on the sliding rod, a limiting ring is arranged on the sliding rod, and a spring is arranged between the limiting ring and the check disk. The connecting rod and the spring are both coated with polytetrafluoroethylene.

[0008] Further, a sliding sleeve unit is arranged at the center position of the check disk. The sliding sleeve unit includes a left flange, a right flange and a sliding sleeve. Among them, the left flange and the right flange are respectively arranged at both ends of the sliding sleeve, and the sliding sleeve is slidably sleeved on the sliding rod.

[0009] Further, a locking screw is arranged at the end of the sliding rod, an adjusting nut is threadedly sleeved on the locking screw, an isolation film is arranged on the surface of the check disk corresponding to the adjusting nut, the isolation film is made of an elastic material, and the edge part of the isolation film is adhered to the surface of the check disk by setting a sealing adhesive edge.

[0010] Further, an anti-slip pad is arranged on the threaded side of the adjusting nut, a clamping head is arranged on the surface of the adjusting nut corresponding to the right flange, and a clamping groove is arranged on the surface of the right flange corresponding to the adjusting nut. The clamping groove is adapted to the clamping head.

[0011] Further, a support rod is arranged on the inlet side of the connecting rod. The support rod is radially arranged on the inner wall of the valve body. The inlet side of the support rod is of a streamlined structure, and a convex flow guide cover is arranged on the inlet side of the support rod.

[0012] Further, a fixing seat is arranged on the outer side of the sliding sleeve, a ring-shaped pivot rod is arranged on the fixing seat, a pivot sleeve is arranged at the bottom of the folding rib, and the pivot sleeve is rotatably sleeved on the pivot rod.

[0013] Further, the inside of the check valve disc is made of elastic silica gel material, the surface of the check valve disc is coated with polytetrafluoroethylene, radial creases are arranged on the surface of the check valve disc, and a sealing edge is arranged at the edge part of the check valve disc, and the sealing edge corresponds to the air outlet side of the check step.

[0014] Further, pipeline mechanisms are arranged at both ends of the valve body. The pipeline mechanisms include an air supply pipe and an air outlet pipe. Among them, the air supply pipe is connected to the air inlet end of the valve body, the air outlet pipe is connected to the air outlet end of the valve body, sealing rings are arranged at the connection parts of the air supply pipe and the air outlet pipe with the valve body, sealing grooves are arranged at both the air inlet end and the air outlet end of the valve body, and the sealing grooves and the sealing rings are clamped with each other.

[0015] Beneficial effects: By installing a self-designed anti-backflow mechanism inside the pipeline at the position in front of each furnace tube and the nitrogen pneumatic valve, the anti-backflow mechanism internally adopts a check step locking structure. When boron trichloride gas passes through normally, the check assembly folds and contracts without gas blockage. When the nitrogen pneumatic valve malfunctions and causes nitrogen backflow, the nitrogen pressure blows the check assembly to unfold reversely, and the check valve disc fits against the check step to achieve the function of blocking the backflow of air flow, avoiding a large number of reworks caused by nitrogen backflow, and effectively reducing the problems of high cost and difficult troubleshooting caused by the abnormality of the nitrogen pneumatic valve.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings, where:

[0018] Figure 1 It is a connection schematic diagram of an anti-gas backflow device for boron diffusion processing of photovoltaic cells according to an embodiment of the present invention;

[0019] Figure 2 It is a front elevation sectional view of a vibration test mechanism in an anti-gas backflow device for boron diffusion processing of photovoltaic cells according to an embodiment of the present invention;

[0020] Figure 3 It is a partial front elevation sectional view of a check assembly in an anti-gas backflow device for boron diffusion processing of photovoltaic cells according to an embodiment of the present invention;

[0021] Figure 4For Figure 3 An enlarged view of A in;

[0022] Figure 5 It is a right - hand sectional view of the check disk in the gas back - flow prevention device for boron diffusion processing of photovoltaic cells according to an embodiment of the present invention;

[0023] Figure 6 A right - hand view of the check disk in the gas back - flow prevention device for boron diffusion processing of photovoltaic cells according to an embodiment of the present invention.

[0024] As shown in the figure: 1. Back - flow prevention mechanism; 11. Valve body; 12. Linkage assembly; 121. Convex flow - guiding cover; 122. Support rod; 123. Link; 13. Check assembly; 131. Check disk; 132. Folding rib; 1321. Pivot sleeve; 133. Isolation membrane; 1331. Sealing adhesive edge; 134. Adjusting nut; 1341. Chuck; 1342. Card slot; 1343. Anti - slip pad; 135. Slide rod; 1351. Locking screw; 136. Slide sleeve unit; 1361. Left flange; 1362. Slide sleeve; 1363. Right flange; 137. Spring; 138. Pivot rod; 1381. Fixed seat; 139. Sealing edge; 1391. Crease; 14. Check step; 15. Limit ring; 2. Pipeline mechanism; 21. Gas supply pipe; 22. Sealing ring; 23. Air outlet pipe; 24. Sealing card slot; 3. Nitrogen pneumatic valve; 4. Furnace tube. Detailed implementation manners

[0025] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation of the present invention.

[0026] The gas back - flow prevention device for boron diffusion processing of photovoltaic cells according to the embodiments of the present invention will be described below with reference to the drawings.

[0027] As Figures 1-3 shown, the gas back - flow prevention device for boron diffusion processing of photovoltaic cells provided by the embodiments of the present invention includes a furnace tube 4 and a nitrogen pneumatic valve 3. The nitrogen pneumatic valve 3 is arranged on the furnace tube 4. An anti - back - flow mechanism 1 is arranged at the input end of the nitrogen pneumatic valve 3, and the anti - back - flow mechanism 1 is used to prevent the mixed gas of boron trichloride and nitrogen from flowing back.

[0028] The anti - back - flow mechanism 1 includes a valve body 11 and a check assembly 13. Among them, the valve body 11 is connected to the input end of the nitrogen pneumatic valve 3, the check assembly 13 is arranged inside the valve body 11, a check step 14 is arranged inside the valve body 11, the caliber of the air - outlet side of the check step 14 is larger than that of the air - inlet side, and the check assembly 13 is arranged on the air - outlet side of the check step 14.

[0029] The check component 13 includes a check disk 131 and folding ribs 132. Among them, the check disk 131 is arranged on the air outlet side of the check step 14, and a plurality of folding ribs 132 are provided. The plurality of folding ribs 132 are radially arranged inside the check disk 131, and the radial center positions of the plurality of folding ribs 132 are pivotally connected.

[0030] Specifically, in the present invention, by installing a backflow prevention mechanism 1 at the position in front of each furnace tube 4 and the nitrogen pneumatic valve 3, the inside of the backflow prevention mechanism 1 adopts a locking structure of the check step 14. When boron trichloride gas passes normally, the check disk 131 folds. Specifically: the boron trichloride gas squeezes the check disk 131 along the direction as shown in Figure 2 to the right, and the check disk 131 and the internal folding ribs 132 are folded and stored together. The volume of the check disk 131 decreases, and the air outlet volume on the air outlet side of the check step 14 increases, enabling the boron trichloride gas to flow smoothly to the right, so that no gas blockage occurs during the transmission of the boron trichloride gas.

[0031] When the nitrogen pneumatic valve 3 malfunctions and causes nitrogen to flow back, the nitrogen pressure blows the check component 13 to unfold reversely, and the check disk 131 fits against the check step 14 to achieve the function of blocking the backflow of the air flow. Specifically: the nitrogen squeezes the check disk 131 along the direction as shown in Figure 2 to the left, and the check disk 131 unfolds reversely along the internal folding ribs 132. After the check disk 131 unfolds, its edge part overlaps on the check step 14, closing the check step 14, avoiding a large number of reworks caused by nitrogen backflow, and effectively reducing the problems of high cost and difficult troubleshooting caused by the malfunction of the nitrogen pneumatic valve 3.

[0032] In an embodiment of the present invention, as shown in Figures 2-4 , a connecting rod assembly 12 is arranged on the air inlet side of the check step 14. The connecting rod assembly 12 is used to restrain the check component 13. The connecting rod assembly 12 includes a connecting rod 123. Among them, the connecting rod 123 is horizontally arranged on the air inlet side of the check step 14. A sliding rod 135 is arranged at the end of the connecting rod 123. The middle position of the check disk 131 is slidably arranged on the sliding rod 135. A limiting ring 15 is arranged on the sliding rod 135. A spring 137 is arranged between the limiting ring 15 and the check disk 131. Both the connecting rod 123 and the spring 137 are coated with polytetrafluoroethylene.

[0033] Specifically, by arranging a spring 137 between the limiting ring 15 and the check disk 131, when the boron trichloride gas passes normally, it pushes the check disk 131 to move to the right along the sliding rod 135, as shown in Figure 2As shown, at this time, the distance between the check disc 131 and the check step 14 becomes larger, further increasing the ventilation volume and reducing the flow resistance of the boron trichloride gas; when the nitrogen pressure blows the check assembly 13 to expand reversely to the left, at this time the spring 137 is compressed, the check disc 131 moves to the left, and the distance between it and the check step 14 shrinks. Then the check disc 131 fits against the check step 14 to achieve the function of blocking the backflow of the air flow.

[0034] When the reflux nitrogen gas pushes the check disc 131 to move to the left and contacts the check step 14, the middle position of the check disc 131 slides to the position of the limit ring 15 and stops. The limit ring 15 limits and supports the middle position of the check disc 131 to improve the effect of preventing gas backflow.

[0035] Since polytetrafluoroethylene coatings are provided on both the connecting rod 123 and the spring 137, the connecting rod 123 and the spring 137 will not chemically react with boron trichloride, and the polytetrafluoroethylene material itself has the advantages of high temperature resistance, corrosion resistance, and poor adhesion, effectively reducing the problem of boron trichloride residue adhesion.

[0036] In an embodiment of the present invention, as Figure 4 shown, a sliding sleeve unit 136 is provided at the central position of the check disc 131. The sliding sleeve unit 136 includes a left flange 1361, a right flange 1363, and a sliding sleeve 1362. Among them, the left flange 1361 and the right flange 1363 are respectively provided at both ends of the sliding sleeve 1362, and the sliding sleeve 1362 is slidably sleeved on the sliding rod 135.

[0037] Specifically, the left flange 1361 and the right flange 1363 are used to fix the check disc 131 clamped therein on one hand. On the other hand, the left flange 1361 is used to connect with the spring 137 to prevent the spring 137 from directly pressing the check disc 131. The sliding sleeve 1362 is used to slide left and right on the sliding rod 135.

[0038] In an embodiment of the present invention, as Figure 4 shown, a locking screw 1351 is provided at the end of the sliding rod 135. An adjusting nut 134 is threadedly sleeved on the locking screw 1351. A separation film 133 is provided on the surface of the check disc 131 corresponding to the adjusting nut 134. The separation film 133 is made of an elastic material, and the edge portion of the separation film 133 is adhesively connected to the surface of the check disc 131 by a sealing adhesive edge 1331.

[0039] Specifically, in order to isolate and protect the adjusting nut 134 and prevent the adjusting nut 134 from being corroded, a separation film 133 is provided on the surface of the check disc 131 corresponding to the adjusting nut 134 to clamp the adjusting nut 134 therein to prevent the adjusting nut 134 from contacting the gas. And since the separation film 133 is made of an elastic material, it plays an elastic protection role for the adjusting nut 134 during the process of the check disc 131 being received and unfolded.

[0040] In one embodiment of the present invention, as Figure 4 shown, an anti-slip pad 1343 is provided on the threaded side of the adjusting nut 134. A chuck 1341 is provided on one side of the adjusting nut 134 corresponding to the right flange 1363, and a clamping groove 1342 is provided on one side of the right flange 1363 corresponding to the adjusting nut 134. The clamping groove 1342 is adapted to the chuck 1341.

[0041] Specifically, in order to adjust the left and right moving distance of the sliding sleeve 1362, and thus adjust the air outlet effect according to the gas flow rate of different velocities. Among them, when the rightward intake velocity of boron trichloride is relatively large, and similarly the nitrogen reflux velocity is also relatively large, by rotating the adjusting nut 134 to the right, the sliding distance of the sliding rod 135 increases, the air outlet of the right side of the check step 14 increases, and the boron trichloride rightward ventilation volume increases, which can be used for the check of gases with a relatively fast flow rate.

[0042] When the rightward flow velocity of boron trichloride is relatively small, and similarly the nitrogen reflux velocity is relatively small, by rotating the adjusting nut 134 to the left, the sliding distance of the sliding rod 135 becomes smaller, the air outlet of the right side of the check step 14 decreases, which can meet the requirements of gases with a relatively slow flow rate. At the same time, the leftward rebound distance of the check disc 131 becomes smaller, and the check is more sensitive.

[0043] Since the anti-slip pad 1343 is provided on the threaded side of the adjusting nut 134 for damping locking after the adjusting nut 134 is adjusted to different positions. Since a chuck 1341 is provided on one side of the adjusting nut 134 corresponding to the right flange 1363, and a clamping groove 1342 is provided on one side of the right flange 1363 corresponding to the adjusting nut 134. After the clamping groove 1342 is engaged with the chuck 1341, the position of the adjusting nut 134 can be adjusted by directly rotating the check disc 131. In addition, the adjusting nut 134 can be disassembled and installed by rotating the check disc 131.

[0044] In one embodiment of the present invention, as Figure 2 shown, a support rod 122 is provided on the intake side of the connecting rod 123. The support rod 122 is radially arranged on the inner wall of the valve body 11. The intake side of the support rod 122 is of a streamline structure, and a convex flow guide cover 121 is provided on the intake side of the support rod 122.

[0045] Specifically, on the one hand, the support rod 122 supports the connecting rod 123. On the other hand, the support rod 122 guides the intake air. The convex flow guide cover 121 has a flow disturbing effect on the gas to prevent the gas from forming a vortex in the valve body 11.

[0046] In one embodiment of the present invention, as Figure 5As shown, a fixed seat 1381 is provided on the outer side of the sliding sleeve 1362. A ring-shaped pivot rod 138 is provided on the fixed seat 1381. A pivot sleeve 1321 is provided at the bottom of the folding rib 132. The pivot sleeve 1321 is rotatably sleeved on the pivot rod 138 to support the folding rib 132 during the folding process.

[0047] Specifically, during the unfolding and storage of the check valve plate 131, the airflow acts on the surface of the check valve plate 131, causing a force on the check valve plate 131, which in turn drives the folding rib 132 to unfold or fold and store along the pivot rod 138.

[0048] In an embodiment of the present invention, as Figure 6 shown, the inside of the check valve plate 131 is made of elastic silicone material. The surface of the check valve plate 131 is provided with a polytetrafluoroethylene coating. The surface of the check valve plate 131 is provided with radial creases 1391. A sealing edge 139 is provided at the edge portion of the check valve plate 131. The sealing edge 139 corresponds to the air outlet side of the check step 14.

[0049] Specifically, the polytetrafluoroethylene coating on the surface of the check valve plate 131 will not react chemically with boron trichloride, and the polytetrafluoroethylene material itself has the advantages of high temperature resistance, corrosion resistance, and poor adhesion, effectively reducing the residue of boron trichloride on the check valve plate 131. The surface of the check valve plate 131 is provided with radial creases 1391. On the one hand, it facilitates the storage and unfolding of the check valve plate 131, and on the other hand, it guides the incoming boron trichloride gas to prevent the gas from rotating to form eddies.

[0050] In an embodiment of the present invention, as Figure 1 and Figure 2 shown, pipeline mechanisms 2 are provided at both ends of the valve body 11. The pipeline mechanisms 2 include an air supply pipe 21 and an air outlet pipe 23. Among them, the air supply pipe 21 is connected to the air inlet end of the valve body 11, the air outlet pipe 23 is connected to the air outlet end of the valve body 11, sealing rings 22 are provided at the connections of the air supply pipe 21 and the air outlet pipe 23 with the valve body 11, and sealing grooves 24 are provided at both the air inlet end and the air outlet end of the valve body 11. The sealing grooves 24 and the sealing rings 22 are engaged with each other.

[0051] Specifically, by using the connection method of the sealing ring 22 and the sealing groove 24 at both ends of the valve body 11, the sealing performance of the pipeline connection is ensured, which is convenient for the disassembly and installation of the furnace tube 4 and the valve body 11.

[0052] To clearly illustrate the above embodiments, referring to Figures 1-6 , the specific working principle of the gas backflow prevention device for boron diffusion processing of photovoltaic cells of the present invention is as follows: During use, by installing a backflow prevention mechanism 1 in front of each furnace tube 4 and the nitrogen pneumatic valve 3. In the backflow prevention mechanism 1, a check step 14 locking structure is adopted inside the valve body 11.

[0053] When boron trichloride gas passes through normally, the check disk 131 is folded and stored. Specifically: The boron trichloride gas squeezes the check disk 131 in the rightward direction as shown in Figure 2 . The check disk 131 and the internal folding ribs 132 are folded and stored together. The volume of the check disk 131 decreases, and the gas outlet volume on the gas outlet side of the check step 14 increases, enabling the boron trichloride gas to flow smoothly to the right, and no gas blockage occurs.

[0054] When the nitrogen pneumatic valve 3 malfunctions and causes nitrogen to flow back, the nitrogen pressure blows the check assembly 13 to unfold reversely to the left, and the check disk 131 fits against the check step 14 to achieve the function of blocking the reverse flow of air. Specifically: The nitrogen squeezes the check disk 131 in the leftward direction as shown in Figure 2 . The check disk 131 unfolds reversely along the internal folding ribs 132. After the check disk 131 unfolds, the edge part overlaps on the check step 14, closing the check step 14, avoiding a large number of reworks caused by nitrogen backflow, and effectively reducing the problems of high cost and difficult troubleshooting caused by the malfunction of the nitrogen pneumatic valve 3.

[0055] In addition, by setting a spring 137 between the limit ring 15 and the check disk 131, when the boron trichloride gas passes through normally, it pushes the check disk 131 to move rightward along the slide rod 135, as shown in Figure 2 . At this time, the distance between the check disk 131 and the check step 14 becomes larger, further increasing the ventilation volume; when the nitrogen pressure blows the check assembly 13 to unfold reversely to the left, the spring 137 is compressed at this time, and the distance between the check disk 131 and the check step 14 shrinks until the check disk 131 completely fits against the check step 14 to achieve the function of blocking the reverse flow of air.

[0056] In the above process, in order to adjust the gas outlet effect according to the airflow of different velocities, when the boron trichloride flows to the right at a relatively high speed, and similarly the nitrogen backflow speed is relatively high, by rotating the adjusting nut 134 to the right, the sliding distance of the slide rod 135 increases, the gas outlet on the right side of the check step 14 increases, and the boron trichloride ventilation volume to the right increases, which can be used for the check of gases with a relatively fast flow rate.

[0057] When the boron trichloride flows to the right at a relatively low speed, and similarly the nitrogen backflow speed is relatively low, by rotating the adjusting nut 134 to the left, the sliding distance of the slide rod 135 becomes smaller, the gas outlet on the right side of the check step 14 decreases, which can meet the requirements of gases with a relatively slow flow rate. At the same time, the distance that the check disk 131 rebounds to the left becomes smaller, and the check is more sensitive.

[0058] Finally, since polytetrafluoroethylene coatings are provided on the check disk 131, the connecting rod 123, and the spring 137, the polytetrafluoroethylene coating does not react with boron trichloride, and the polytetrafluoroethylene material itself has the advantages of high temperature resistance, corrosion resistance, and poor adhesion, effectively reducing the problem of boron trichloride residue adhesion.

[0059] In summary, for the gas backflow prevention device used in the boron diffusion process of the photovoltaic cell according to the embodiments of the present invention, by installing a backflow prevention mechanism inside the pipeline at the position before each furnace tube and the nitrogen pneumatic valve, the overall backflow prevention mechanism is made of polytetrafluoroethylene (including the spring), which will not chemically react with boron trichloride; and the polytetrafluoroethylene material itself has the advantages of high temperature resistance, corrosion resistance, and poor adhesion, effectively reducing the problem of boron trichloride residue adhesion. The two ends of the valve body are connected by a sealing ring and a sealing card slot to ensure the sealing performance of the pipeline connection and the convenient disassembly effect; the inside of the valve body adopts a check step locking structure. When boron trichloride gas passes normally, the check component folds and contracts without gas blockage. When the nitrogen pneumatic valve malfunctions and causes nitrogen backflow, the nitrogen pressure blows the check component to expand reversely, and the check disc fits the check step to achieve the function of blocking the backflow of the air flow, avoiding a large number of reworks caused by nitrogen backflow, and effectively reducing the problems of high cost and difficult troubleshooting caused by the abnormality of the nitrogen pneumatic valve.

[0060] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An anti-gas backflow device for boron diffusion processing of a photovoltaic cell, comprising a furnace tube (4) and a nitrogen pneumatic valve (3), the nitrogen pneumatic valve (3) is arranged on the furnace tube (4), and is characterized in that, An anti-backflow mechanism (1) is provided at the input end of the nitrogen pneumatic valve (3); The anti-backflow mechanism (1) includes a valve body (11) and a check valve assembly (13). Among them, the valve body (11) is connected to the input end of the nitrogen pneumatic valve (3), the check valve assembly (13) is arranged inside the valve body (11), a check valve step (14) is arranged inside the valve body (11), the outlet side diameter of the check valve step (14) is larger than the inlet side diameter, and the check valve assembly (13) is arranged on the outlet side of the check valve step (14); The check valve assembly (13) includes a check valve disc (131) and folding ribs (132). Among them, the check valve disc (131) is arranged on the outlet side of the check valve step (14), there are multiple folding ribs (132), and the multiple folding ribs (132) are radially arranged inside the check valve disc (131), and the radial center positions of the multiple folding ribs (132) are pivotally connected.

2. The gas backflow prevention device for boron diffusion processing of photovoltaic cells according to claim 1, characterized in that A connecting rod assembly (12) is arranged on the inlet side of the check valve step (14), and the connecting rod assembly (12) is used to restrain the check valve assembly (13). The connecting rod assembly (12) includes a connecting rod (123). Among them, the connecting rod (123) is horizontally arranged on the inlet side of the check valve step (14); A sliding rod (135) is arranged at the end of the connecting rod (123), the middle position of the check valve disc (131) is slidably arranged on the sliding rod (135), a limit ring (15) is arranged on the sliding rod (135), a spring (137) is arranged between the limit ring (15) and the check valve disc (131), and both the connecting rod (123) and the spring (137) are coated with polytetrafluoroethylene.

3. The anti-gas backflow device for boron diffusion processing of photovoltaic cells according to claim 2, characterized in that, A sliding sleeve unit (136) is arranged at the central position of the check valve disc (131). The sliding sleeve unit (136) includes a left flange (1361), a right flange (1363) and a sliding sleeve (1362). Among them, the left flange (1361) and the right flange (1363) are respectively arranged at both ends of the sliding sleeve (1362), and the sliding sleeve (1362) is slidably sleeved on the sliding rod (135).

4. The gas reflux prevention device for boron diffusion processing of photovoltaic cells according to claim 3, characterized in that, A locking screw (1351) is arranged at the end of the sliding rod (135), an adjusting nut (134) is threadedly sleeved on the locking screw (1351), a separating membrane (133) is arranged on the surface of the check valve disc (131) corresponding to the adjusting nut (134), the separating membrane (133) is made of an elastic material, and the edge part of the separating membrane (133) is adhered to the surface of the check valve disc (131) by a sealing adhesive edge (1331).

5. The gas reflux prevention device for boron diffusion processing of photovoltaic cells according to claim 4, characterized in that, An anti-slip pad (1343) is arranged on the threaded side of the adjusting nut (134), a chuck (1341) is arranged on the surface of the adjusting nut (134) corresponding to the right flange (1363), a card slot (1342) is arranged on the surface of the right flange (1363) corresponding to the adjusting nut (134), and the card slot (1342) is adapted to the chuck (1341).

6. The anti-gas backflow device for boron diffusion processing of photovoltaic cells according to claim 2, characterized in that, The intake side of the connecting rod (123) is provided with a support rod (122). The support rod (122) is radially arranged on the inner wall of the valve body (11). The intake side of the support rod (122) has a streamlined structure, and a convex flow guide cover (121) is arranged on the intake side of the support rod (122).

7. The anti-gas backflow device for boron diffusion processing of photovoltaic cells according to claim 3, characterized in that, A fixed seat (1381) is arranged on the outer side of the sliding sleeve (1362). A ring-shaped pivot rod (138) is arranged on the fixed seat (1381). A pivot sleeve (1321) is arranged at the bottom of the folding rib (132), and the pivot sleeve (1321) is rotatably sleeved on the pivot rod (138).

8. The anti-gas backflow device for boron diffusion processing of photovoltaic cells according to claim 1, characterized in that, The inside of the check disk (131) is made of elastic silica gel material. The surface of the check disk (131) is coated with polytetrafluoroethylene. Radial creases (1391) are arranged on the surface of the check disk (131). A sealing edge (139) is arranged at the edge part of the check disk (131), and the sealing edge (139) corresponds to the outlet side of the check step (14).

9. The anti-gas backflow device for boron diffusion processing of photovoltaic cells according to claim 1, wherein, Pipeline mechanisms (2) are arranged at both ends of the valve body (11). The pipeline mechanisms (2) include an air supply pipe (21) and an air outlet pipe (23). Among them, the air supply pipe (21) is connected to the intake end of the valve body (11), the air outlet pipe (23) is connected to the outlet end of the valve body (11), sealing rings (22) are arranged at the connection parts of the air supply pipe (21) and the air outlet pipe (23) with the valve body (11), sealing grooves (24) are arranged at both the intake end and the outlet end of the valve body (11), and the sealing grooves (24) and the sealing rings (22) are clamped with each other.

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