Polycrystalline silicon reduction furnace

Abstract

The utility model provides a polycrystalline silicon reduction furnace which comprises a reduction furnace body, an exhaust pipeline assembly and a flow limiting assembly, the reduction furnace body is provided with an exhaust port, and the exhaust pipeline assembly communicates with the exhaust port; the flow limiting assembly comprises at least one of a first flow limiting piece and a second flow limiting piece, the first flow limiting piece and the second flow limiting piece are arranged on the exhaust pipeline assembly, the first flow limiting piece is used for adjusting the resistance drop of the exhaust pipeline assembly, and the second flow limiting piece is used for adjusting the flow of the exhaust pipeline assembly. According to the polycrystalline silicon reduction furnace provided by the invention, during gas replacement, the abrasion of silicon powder to the exhaust pipeline assembly is relatively small.

Description

Technical Field

[0001] The present application relates to the technical field of polysilicon production equipment, and in particular to a polysilicon reduction furnace. Background Art

[0002] The current mainstream polysilicon production process adopts the modified Siemens method. In the reduction section, hydrogen is used to reduce gaseous trichlorosilane, and chemical vapor deposition is performed on the silicon core in the reduction furnace to generate rod-shaped polysilicon.

[0003] In related technologies, the reduction furnace production process is an intermittent operation, with the furnace opened regularly to unload polysilicon rods and install silicon cores. To ensure the gas environment inside the reduction furnace and ensure on-site operation safety, the reduction furnace needs to be replaced multiple times with hydrogen and nitrogen. That is, before starting the deposition reaction, the air in the reduction furnace needs to be replaced with hydrogen. First, nitrogen is used to replace the air, and then hydrogen is used to replace the nitrogen, so that the reduction furnace is filled with hydrogen. After the deposition reaction is completed, nitrogen is used to replace the hydrogen, and then air is used to replace the nitrogen, so that the reduction furnace is filled with air. During the dismantling and replacement process of the reduction furnace, the exhaust gas will carry powdered silicon powder that has not been deposited on the polysilicon, which can easily cause wear and tear on the subsequent replacement pipelines. Utility Model Content

[0004] Based on this, the present application provides a polysilicon reduction furnace to address the deficiencies in the related art.

[0005] The polysilicon reduction furnace provided in an embodiment of the present application includes a reduction furnace body, an exhaust pipe assembly and a current limiting assembly. The reduction furnace body has an exhaust port, and the exhaust pipe assembly is connected to the exhaust port.

[0006] The flow limiting assembly includes at least one of a first flow limiting member and a second flow limiting member. The first flow limiting member and the second flow limiting member are arranged in the exhaust pipe assembly. The first flow limiting member is used to adjust the resistance drop of the exhaust pipe assembly, and the second flow limiting member is used to adjust the flow of the exhaust pipe assembly.

[0007] In one possible implementation, the polysilicon reduction furnace provided in the present application, the first flow limiting component includes a first flow limiting orifice plate, the first flow limiting orifice plate is connected to the exhaust pipe assembly, the first flow limiting orifice plate has a plurality of first flow limiting holes, and the first flow limiting holes pass through the opposite sides of the first flow limiting orifice plate.

[0008] In one possible implementation, the polysilicon reduction furnace provided in the present application also includes a second flow limiting orifice plate, which has a plurality of second flow limiting holes. The second flow limiting holes pass through the opposite sides of the second flow limiting orifice plate, and the second flow limiting orifice plate is rotatably connected to the first flow limiting orifice plate so that the second flow limiting holes are at least partially offset from the first flow limiting holes.

[0009] In one possible implementation, the polysilicon reduction furnace provided in the present application has at least two first flow limiting orifices, at least two first flow limiting orifices are spaced apart in the exhaust duct assembly, and along the fluid flow direction of the exhaust duct assembly, the aperture of the first flow limiting hole of each first flow limiting orifice gradually increases.

[0010] In a possible implementation, in the polysilicon reduction furnace provided in the present application, the second flow limiting member includes at least one pressure regulating valve, and the at least one pressure regulating valve is disposed at one end of the exhaust pipe assembly close to the exhaust port.

[0011] In one possible implementation, the polysilicon reduction furnace provided in the present application, the exhaust duct assembly includes a main pipe, a first branch pipe, a second branch pipe and a third branch pipe, the main pipe is connected to the exhaust port, the first branch pipe, the second branch pipe and the third branch pipe are all connected to the main pipe, and the flow limiting assembly is arranged in at least one of the main pipe, the first branch pipe, the second branch pipe and the third branch pipe.

[0012] In a possible implementation, the polysilicon reduction furnace provided in the present application has a main pipe comprising at least two pipe sections connected in sequence, and the diameters of the at least two pipe sections increase in sequence along the fluid flow direction of the main pipe.

[0013] In one possible implementation, the polysilicon reduction furnace provided in the present application, the exhaust duct assembly also includes a first elbow, a second elbow and a third elbow, the first branch pipe is connected to the main pipe through the first elbow, the second branch pipe is connected to the main pipe through the second elbow, and the third branch pipe is connected to the main pipe through the third elbow.

[0014] In a possible implementation, in the polysilicon reduction furnace provided in the present application, the bending directions of the first elbow, the second elbow, and the third elbow are consistent, and the bending radii of the first elbow, the second elbow, and the third elbow are the same.

[0015] In a possible implementation, in the polysilicon reduction furnace provided in the present application, the bending radius R of the first elbow and the diameter D of the first branch pipe satisfy: R≥1.5D.

[0016] The present application provides a polysilicon reduction furnace, which includes a reduction furnace body, an exhaust duct assembly, and a flow limiting assembly. The reduction furnace body includes an exhaust port, and the flow limiting assembly includes a first flow limiting member and / or a second flow limiting member. The exhaust port is provided for connecting to the exhaust duct assembly, thereby allowing exhaust gas provided by an exhaust source to enter the reduction furnace body through the exhaust port, and allowing gas to be exhausted in the reduction furnace body to be exhausted through the exhaust port. The exhaust duct assembly is provided for connecting the exhaust source and the reduction furnace body, thereby allowing the exhaust gas and the gas to be exhausted to be exchanged through the exhaust duct assembly. The first flow limiting member is provided for adjusting the flow resistance of the exhaust duct assembly, thereby adjusting the fluid flow velocity of the exhaust duct assembly. The second flow limiting member is provided for adjusting the flow rate of the exhaust duct assembly, thereby adjusting the fluid flow velocity of the exhaust duct assembly. In this way, through the adjustment of the first flow limiting member or the second flow limiting member, or through the coordinated action of the first flow limiting member and the second flow limiting member, the fluid flow velocity of the exhaust duct assembly can be effectively limited, thereby reducing the scouring force generated by silicon powder on the exhaust duct assembly when following the gas flow, thereby reducing the wear of the silicon powder on the exhaust duct assembly.

[0017] In addition to the technical problems solved by the embodiments of the present application described above, the technical features that constitute the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions, other technical problems that can be solved by the polysilicon reduction furnace provided by the present application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a schematic structural diagram of the polysilicon reduction furnace provided in an embodiment of the present application.

[0020] Description of reference numerals:

[0021] 100-reduction furnace body;

[0022] 200-Exhaust duct assembly;

[0023] 210-General Manager;

[0024] 220-first branch;

[0025] 230-second branch;

[0026] 240 - third branch pipe;

[0027] 250 - first elbow;

[0028] 260 - second elbow;

[0029] 270 - third elbow;

[0030] 300 - flow restriction assembly;

[0031] 310 - first flow restriction member;

[0032] 320 - second flow restriction member. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be described in more detail below in combination with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar notations represent the same or similar parts or parts having the same or similar functions throughout. The described embodiments are part of the embodiments of the present application, not all the embodiments. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below in combination with the drawings.

[0034] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or indirect connection through an intermediate medium, or internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0036] The terms "first", "second", "third" (if any) in the description and claims of this application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a particular order or sequence. It should be understood that the data thus used can be interchanged, where appropriate, so that the embodiments of the application described herein can be carried out in other than the order shown or described herein.

[0037] In addition, the terms "comprising" and "having", as well as any variations thereof, are intended to cover non-exclusive inclusions, for example, a process, method, system, product or display comprising a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or displays.

[0038] In the related art, the production process of the reduction furnace is intermittent operation, and the polycrystalline silicon rods are unloaded and the silicon cores are installed periodically. In order to ensure the gas environment in the furnace cylinder of the reduction furnace and ensure the safety of the site operation, the reduction furnace needs to be replaced by hydrogen and nitrogen multiple times, that is, before the deposition reaction starts, the air in the reduction furnace needs to be replaced by hydrogen, first by nitrogen and then by hydrogen, so that the reduction furnace is filled with hydrogen. After the deposition reaction is completed, the hydrogen needs to be replaced by nitrogen, and then the nitrogen needs to be replaced by air, so that the reduction furnace is filled with air. During the disassembly and replacement process of the reduction furnace, the exhaust gas will carry the powdery silicon powder that has not been deposited on the polycrystalline silicon, which is easy to cause wear to the subsequent replacement pipeline.

[0039] Therefore, the embodiments of the present application provide a polycrystalline silicon reduction furnace, which sets a flow limiting assembly on the exhaust pipe assembly to limit the fluid velocity of the exhaust pipe assembly, thereby reducing the wear of the silicon powder in the exhaust gas to the exhaust pipe assembly.

[0040] The specific embodiments of the polycrystalline silicon reduction furnace provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0041] Referring to Figure 1 As shown in the drawings, the polycrystalline silicon reduction furnace provided by the embodiments of the present application includes a reduction furnace body 100, an exhaust pipe assembly 200 and a flow limiting assembly 300. The reduction furnace body 100 has an exhaust port, and the exhaust pipe assembly 200 is communicated with the exhaust port.

[0042] The flow limiting assembly 300 includes at least one of a first flow limiting member 310 and a second flow limiting member 320. The first flow limiting member 310 and the second flow limiting member 320 are arranged on the exhaust pipe assembly 200. The first flow limiting member 310 is used to adjust the resistance drop of the exhaust pipe assembly 200, and the second flow limiting member 320 is used to adjust the flow of the exhaust pipe assembly 200.

[0043] In the present application, the reduction furnace body 100 can provide a reaction place for the reduction of polysilicon, and the exhaust pipe assembly 200 is used to connect the exhaust source and the reduction furnace body 100 to allow gas to circulate between the exhaust source and the reduction furnace body 100, thereby filling the reduction furnace body 100 with the required exhaust gas. The flow limiting assembly 300 is used to limit the fluid velocity of the exhaust pipe assembly 200 to reduce the wear of the exhaust pipe assembly 200 when silicon powder flows with the exhaust gas.

[0044] Specifically, the flow limiting assembly 300 may include only the first flow limiting member 310, or the flow limiting assembly 300 may include only the second flow limiting member 320, or the flow limiting assembly 300 may include both the first flow limiting member 310 and the second flow limiting member 320, the first flow limiting member 310 is used to adjust the resistance drop of the exhaust pipe assembly 200, and the second flow limiting member 320 is used to adjust the flow rate of the exhaust pipe assembly 200.

[0045] When the flow limiting assembly 300 only includes the first flow limiting member 310, the first flow limiting member 310 is arranged in the exhaust pipe assembly 200; when the flow limiting assembly 300 only includes the second flow limiting member 320, the second flow limiting member 320 is arranged in the exhaust pipe assembly 200; when the flow limiting assembly 300 includes both the first flow limiting member and the second flow limiting member 320, the first flow limiting member 310 and the second flow limiting member 320 are both arranged in the exhaust pipe assembly 200.

[0046] In this way, at least one of the first flow restricting member 310 and the second flow restricting member 320 is arranged in the exhaust duct assembly 200. The first flow restricting member 310 can increase the resistance drop of the exhaust duct assembly 200, thereby adjusting the fluid velocity of the exhaust duct assembly 200. The second flow restricting member 320 can reduce the flow rate of the exhaust duct assembly 200, thereby adjusting the fluid velocity of the exhaust duct assembly 200. In this way, the flow restricting assembly 300 can effectively limit the fluid velocity of the exhaust duct assembly 200, thereby reducing the wear of the exhaust duct assembly 200 by silicon powder.

[0047] The polysilicon reduction furnace provided in the embodiment of the present application includes a reduction furnace body 100, an exhaust pipe assembly 200 and a flow limiting assembly 300. The reduction furnace body 100 includes an exhaust port, and the flow limiting assembly 300 includes a first flow limiting member 310 and / or a second flow limiting member 320. The exhaust port is provided for connecting the exhaust pipe assembly 200, so that the exhaust gas provided by the exhaust source enters the reduction furnace body 100 through the exhaust port, and the gas to be exhausted in the reduction furnace body 100 is discharged through the exhaust port. The exhaust pipe assembly 200 is provided for connecting the exhaust source and the reduction furnace body 100, so that the exhaust gas and the gas to be exhausted are exchanged through the exhaust pipe assembly 200. The first flow limiting member 310 is provided for adjusting the flow resistance of the exhaust pipe assembly 200, so as to adjust the flow resistance of the exhaust pipe assembly 200. The fluid flow rate is adjusted by setting a second flow restrictor 320 for adjusting the flow of the exhaust pipe assembly 200, thereby adjusting the fluid flow rate of the exhaust pipe assembly 200. In this way, through the adjustment of the first flow restrictor 310 or the second flow restrictor 320, or through the coordinated action of the first flow restrictor 310 and the second flow restrictor 320, the fluid flow rate of the exhaust pipe assembly 200 can be effectively limited, thereby reducing the scouring force generated by the silicon powder on the exhaust pipe assembly 200 when following the gas flow, thereby reducing the wear of the silicon powder on the exhaust pipe assembly 200.

[0048] In one possible implementation, the first flow restricting member 310 includes a first flow restricting orifice plate connected to the exhaust pipe assembly 200 . The first flow restricting orifice plate has a plurality of first flow restricting holes that pass through opposite sides of the first flow restricting orifice plate.

[0049] In this way, when the fluid passes through the first flow restriction orifice, the first flow restriction orifice will generate resistance to the fluid, thereby increasing the flow resistance of the fluid, thereby reducing the flow speed of the fluid in the exhaust pipe assembly 200, thereby reducing the wear of the exhaust pipe assembly 200 by silicon powder.

[0050] In some embodiments, the first flow limiting member 310 also includes a second flow limiting orifice plate, which has a plurality of second flow limiting holes, and the second flow limiting holes pass through the opposite sides of the second flow limiting orifice plate. The second flow limiting orifice plate is rotatably connected to the first flow limiting orifice plate so that the second flow limiting holes are at least partially offset from the first flow limiting holes.

[0051] It should be noted that the flow rate of the first flow restrictor 310 is primarily determined by the aperture of the first flow restrictor 310. When the first flow restrictor 310 includes a first flow restrictor plate and a second flow restrictor plate, the second flow restrictor plate can be rotated relative to the first flow restrictor plate. Therefore, when the aperture of the first flow restrictor 310 needs to be adjusted, the second flow restrictor plate can be rotated so that the first flow restrictor hole of the first flow restrictor plate and the second flow restrictor hole of the second flow restrictor plate are partially offset from each other. The greater the overlap between the two, the larger the aperture of the first flow restrictor 310, and the greater the offset between the two, the smaller the aperture of the first flow restrictor 310. This arrangement facilitates flexible adjustment of the resistance drop of the exhaust duct assembly 200 as needed.

[0052] In some embodiments, there are at least two first flow limiting orifices, and at least two first flow limiting orifices are spaced apart in the exhaust pipe assembly 200 . Along the fluid flow direction of the exhaust pipe assembly 200 , the aperture of the first flow limiting hole of each first flow limiting orifice gradually increases.

[0053] In this way, along the fluid flow direction of the exhaust pipe assembly 200, when the aperture of the multiple first flow limiting orifices gradually increases, the flow velocity of the fluid can be gradually reduced, and then the flow velocity of the fluid can be adjusted to within the required range, thereby effectively reducing the scouring force of the silicon powder on the exhaust pipe assembly 200, thereby reducing the wear of the silicon powder on the exhaust pipe assembly 200.

[0054] In a possible implementation, the second flow restrictor 320 includes at least one pressure regulating valve, and the at least one pressure regulating valve is disposed at one end of the exhaust pipe assembly 200 close to the exhaust port.

[0055] In this way, the pressure regulating valve can adjust the flow of the exhaust pipe assembly 200, and further adjust the flow speed of the fluid in the exhaust pipe assembly 200, thereby effectively reducing the wear of the exhaust pipe assembly 200 by silicon powder.

[0056] Among them, when there is only one pressure regulating valve, the pressure regulating valve can be set at one end of the exhaust pipe assembly 200 close to the exhaust port, so that when the gas to be replaced comes out of the reduction furnace body 100, it can first pass through the pressure regulating valve, and then reduce the fluid speed to a preset value, thereby reducing the wear of the subsequent exhaust pipe assembly 200 by silicon powder.

[0057] Reference Figure 1 As shown, in a specific implementation, the exhaust pipe assembly 200 includes a main pipe 210, a first branch pipe 220, a second branch pipe 230 and a third branch pipe 240, the main pipe 210 is connected to the exhaust port, the first branch pipe 220, the second branch pipe 230 and the third branch pipe 240 are all connected to the main pipe 210, and the flow limiting assembly 300 is arranged in at least one of the main pipe 210, the first branch pipe 220, the second branch pipe 230 and the third branch pipe 240.

[0058] It is understood that the main pipe 210 and the first branch pipe 220 can form a first flow channel for the flow of a first exhaust gas, the main pipe 210 and the second branch pipe 230 can form a second flow channel for the flow of a second exhaust gas, and the main pipe 210 and the third branch pipe 240 can form a third flow channel for the flow of a third exhaust gas, thereby enabling the exhaust duct assembly 200 to meet the exhaust requirements of the reduction furnace body 100. A flow limiting assembly 300 is provided on at least one of the first branch pipe 220, the second branch pipe 230, and the third branch pipe 240 to limit the flow rate of at least one of the first flow channel, the second flow channel, and the third flow channel. The flow limiting assembly 300 is provided on the main pipe 210 to limit the flow rate of the first flow channel, the second flow channel, and the third flow channel.

[0059] The first exhaust gas may be hydrogen, the second exhaust gas may be nitrogen, and the third exhaust gas may be a hydrogen-nitrogen mixed gas.

[0060] In a possible implementation, the main pipe 210 includes at least two pipe sections connected in sequence, and along the fluid flow direction of the main pipe 210 , the diameters of the at least two pipe sections increase in sequence.

[0061] It can be understood that under the same pressure, the larger the pipe diameter, the smaller the flow rate. Therefore, the main pipe 210 can be set to at least two sections, and the pipe diameters of each pipe section increase successively along the flow direction of the main pipe 210, so that the flow rate of each pipe section decreases successively along the flow direction of the main pipe 210, thereby reducing the wear of silicon powder on the first branch pipe 220, the second branch pipe 230 and the third branch pipe 240.

[0062] Reference Figure 1 As shown, in one possible implementation, the exhaust pipe assembly 200 further includes a first elbow 250, a second elbow 260 and a third elbow 270, the first branch pipe 220 is connected to the main pipe 210 through the first elbow 250, the second branch pipe 230 is connected to the main pipe 210 through the second elbow 260, and the third branch pipe 240 is connected to the main pipe 210 through the third elbow 270.

[0063] In the actual production process, the exhaust pipe assembly 200 can use elbows to connect pipe sections in different directions. The elbows are more severely scoured due to the change in the direction of fluid flow. Therefore, by setting the first elbow 250, the pipe bending radius can be increased, and the direct scouring of pipe sections in different directions can be reduced. By setting the second elbow 260, the pipe bending radius can be increased, and the direct scouring of pipe sections in different directions can be reduced. By setting the third elbow 270, the pipe bending radius can be increased, and the direct scouring of pipe sections in different directions can be reduced. This effectively reduces the wear of the exhaust pipe assembly 200 by silicon powder.

[0064] In some embodiments, the first elbow 250 , the second elbow 260 , and the third elbow 270 have the same bending radius, which can reduce the installation space of the exhaust duct assembly 200 and reduce the cost of the exhaust duct assembly 200 .

[0065] In some embodiments, the bending radius R of the first elbow 250 and the diameter D of the first branch pipe 220 satisfy: R≥1.5D.

[0066] That is to say, the first elbow 250 , the second elbow 260 and the third elbow 270 are all elbows with R≥1.5D, which have good wear resistance and can effectively reduce the flow velocity of the fluid.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A polysilicon reduction furnace, characterized in that: It includes a reduction furnace body, an exhaust pipe assembly and a flow limiting assembly, wherein the reduction furnace body has an exhaust port, and the exhaust pipe assembly is connected to the exhaust port; The flow limiting component includes at least one of a first flow limiting member and a second flow limiting member, the first flow limiting member and the second flow limiting member are arranged in the exhaust pipe component, the first flow limiting member is used to adjust the resistance drop of the exhaust pipe component, and the second flow limiting member is used to adjust the flow rate of the exhaust pipe assembly.

2. The polysilicon reduction furnace according to claim 1, characterized in that: The first flow limiting member includes a first flow limiting orifice plate, which is connected to the exhaust pipe assembly. The first flow limiting orifice plate has a plurality of first flow limiting holes, which pass through opposite sides of the first flow limiting orifice plate.

3. The polysilicon reduction furnace according to claim 2, characterized in that: It also includes a second flow limiting orifice plate, which has a plurality of second flow limiting holes. The second flow limiting holes pass through the opposite sides of the second flow limiting orifice plate, and the second flow limiting orifice plate is rotatably connected to the first flow limiting orifice plate so that the second flow limiting holes are at least partially offset from the first flow limiting holes.

4. The polysilicon reduction furnace according to claim 2, characterized in that: There are at least two first flow limiting orifices, and at least two first flow limiting orifices are spaced apart in the exhaust pipe assembly. Along the fluid flow direction of the exhaust pipe assembly, the aperture of the first flow limiting hole of each first flow limiting orifice gradually increases.

5. The polysilicon reduction furnace according to claim 1, characterized in that: The second flow restricting member includes at least one pressure regulating valve, and the at least one pressure regulating valve is arranged at one end of the exhaust pipe assembly close to the exhaust port.

6. The polysilicon reduction furnace according to any one of claims 1 to 5, characterized in that: The exhaust pipe assembly includes a main pipe, a first branch pipe, a second branch pipe and a third branch pipe. The main pipe is connected to the exhaust port. The first branch pipe, the second branch pipe and the third branch pipe are all connected to the main pipe. The flow limiting assembly is arranged on at least one of the main pipe, the first branch pipe, the second branch pipe and the third branch pipe.

7. The polysilicon reduction furnace according to claim 6, characterized in that: The main pipe includes at least two pipe sections connected in sequence, and along the fluid flow direction of the main pipe, the diameters of the at least two pipe sections increase in sequence.

8. The polysilicon reduction furnace according to claim 6, characterized in that: The exhaust pipe assembly further includes a first elbow, a second elbow and a third elbow. The first branch pipe is connected to the main pipe through the first elbow, the second branch pipe is connected to the main pipe through the second elbow, and the third branch pipe is connected to the main pipe through the third elbow.

9. The polysilicon reduction furnace according to claim 8, characterized in that: The bending directions of the first elbow, the second elbow, and the third elbow are consistent, and the bending radii of the first elbow, the second elbow, and the third elbow are the same.

10. The polysilicon reduction furnace according to claim 9, characterized in that: The bending radius R of the first elbow and the diameter D of the first branch pipe satisfy: R≥1.5D.

Images