An adaptive feed nozzle for a polysilicon reduction furnace

Abstract

An adaptive feeding nozzle for a polycrystalline silicon reduction furnace, relating to the field of artificial crystal preparation, is disclosed. This invention utilizes an elastic element between the inner sleeve and the piston, which drives the piston to reciprocate up and down, thereby adaptively adjusting the flow area of ​​the nozzle. The flow area changes dynamically with variations in the nozzle's working pressure and the gas medium flow rate, thus stabilizing the gas medium injection velocity, reducing fluctuations in the injection velocity, and stabilizing the gas medium injection distribution. This, in turn, stabilizes the gas medium flow field distribution within the reduction furnace, ensuring high product yield under different operating conditions, and is suitable for widespread promotion and application.

Description

Technical Field

[0001] This utility model relates to the field of artificial crystal preparation, specifically to an adaptive feed nozzle for a polycrystalline silicon reduction furnace. Background Technology

[0002] With the rapid development of the solar energy industry, the demand for polycrystalline silicon, as an important raw material for solar cells, has also increased. For polycrystalline silicon production, over 90% of companies use the modified Siemens process. Its basic reaction principle is as follows: high-purity trichlorosilane (containing a small amount of dichlorosilane) is mixed with hydrogen and introduced into a reduction furnace. In the furnace, a vapor-phase chemical deposition reaction occurs at a temperature exceeding 1000℃ and a pressure of 0.4–0.7 MPa. Silicon crystals are deposited on an electrically heated silicon core. The reaction stops when the silicon core gradually grows from an initial diameter of 8–15 mm to 140–170 mm. The high-purity silicon rod is then removed from the reduction furnace to obtain the desired polycrystalline silicon product.

[0003] During the growth process of polycrystalline silicon rods, the raw material (a mixture of trichlorosilane and hydrogen) enters the reduction furnace in a gaseous state. That is, the feeding process is achieved through multiple nozzles distributed on the bottom of the reduction furnace. The raw material is distributed from the main feed pipe to each spray nozzle. The spray nozzles are fixed to the bottom of the reduction furnace by threads or other means. The spray direction of the nozzles is perpendicular to the bottom of the reduction furnace and upward. When the feed gas enters, it is sprayed by the nozzles and forms a dendritic distribution state, thereby creating the required reduction reaction environment in the reduction furnace, crystallizing polycrystalline silicon on the silicon core. At the same time, the exhaust gas is discharged from the reduction furnace through the exhaust port.

[0004] However, during the actual operation of the reduction furnace, when the feed rate needs to be adjusted, it is usually regulated by the upstream feed control system to control the feed pressure and flow rate. However, most existing reduction furnace spray nozzles adopt a fixed nozzle structure, that is, the nozzle orifice flow area is a fixed nozzle design structure. When the working pressure and flow rate of the nozzle change, the distribution state formed after the nozzle sprays will change, resulting in changes in the medium distribution in the internal space of the reduction furnace. This leads to unstable fluidity, heat exchange, and mass transfer, resulting in uneven flow field distribution in the reduction furnace, and consequently, problems such as poor silicon rod morphology, unqualified products, and operational safety hazards.

[0005] Therefore, how to provide an adaptive feed nozzle (i.e., a gas injection nozzle that can adapt to different flow rate changes) for polysilicon reduction furnaces has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0006] To overcome the shortcomings of the prior art, this utility model provides an adaptive feeding nozzle for a polysilicon reduction furnace. This utility model can adjust the gas medium flow area of ​​the nozzle according to changes in flow conditions, thereby avoiding the problems of large changes in gas medium distribution and unstable working state in the reduction furnace caused by the existing fixed nozzle structure.

[0007] To achieve the aforementioned inventive objective, this utility model adopts the following technical solution:

[0008] An adaptive feed nozzle for a polycrystalline silicon reduction furnace includes a piston, a shell, an elastic element, an inner sleeve, and an end cap. The inner sleeve has a circular ring structure. An end cap is provided at the lower end of the inner hole in the middle of the inner sleeve, blocking the lower end of the inner hole in the middle of the inner sleeve. An elastic element is provided above the end cap, and a piston is provided above the elastic element. The lower end of the piston is located above the inner hole in the middle of the inner sleeve, and the piston reciprocates up and down in the inner hole in the middle of the inner sleeve through the elastic element. At least one air guide hole is provided in the middle of the piston. An outwardly extending ring is provided in the middle of the outer edge surface of the inner sleeve. A plurality of through air holes are provided at intervals on the upper surface of the ring. The outer edge surface of the ring is inserted into and fixed in the inner hole of the shell. A constriction is provided at the upper end of the inner hole of the shell. The upper end of the piston is located in the constriction, and a gap is left between the inner edge surface of the constriction and the outer edge surface of the piston, forming a nozzle. The lower end of the inner hole of the shell is connected to the air inlet on the bottom of the reduction furnace.

[0009] The adaptive feed nozzle for the polycrystalline silicon reduction furnace has an outwardly extending lower annular boss on the outer edge of the lower end of the piston.

[0010] The adaptive feed nozzle for the polycrystalline silicon reduction furnace has an inwardly extending upper annular boss on the inner edge surface of the upper end of the inner hole in the middle of the inner sleeve.

[0011] The adaptive feed nozzle for a polycrystalline silicon reduction furnace, wherein the elastic element is a spring.

[0012] The adaptive feed nozzle for the polycrystalline silicon reduction furnace has a vent hole that is any one of the following shapes: circular, elliptical, oblong, square, or polygonal.

[0013] The adaptive feed nozzle for the polycrystalline silicon reduction furnace has a first structure in which the end cap is connected to the lower end of the inner hole in the middle of the inner sleeve. The end cap has an external thread on its outer edge surface and an internal thread on its inner edge surface at the lower end of the inner hole in the middle of the inner sleeve. The internal thread and the external thread are threaded together. At least one set of screw holes is provided on the bottom of the end cap.

[0014] The adaptive feed nozzle for the polycrystalline silicon reduction furnace has a second structure in which the end cap is welded to the lower end of the inner hole in the middle of the inner sleeve when the end cap is connected to the lower end of the inner hole in the middle of the inner sleeve.

[0015] The adaptive feed nozzle for the polycrystalline silicon reduction furnace is provided in which the outer edge of the upper end of the piston is configured as a conical structure with a smaller upper end and a larger lower end, or the upper end of the piston is configured as a hemispherical structure.

[0016] The adaptive feed nozzle for the polycrystalline silicon reduction furnace has a conical shape with a smaller opening at the top and a larger opening at the bottom, or a hemispherical shape with a smaller opening at the top and a larger opening at the bottom.

[0017] The adaptive feed nozzle for the polycrystalline silicon reduction furnace has an outer edge surface of the upper end of the outer shell configured as a tapered structure with a smaller upper end and a larger lower end.

[0018] By adopting the technical solution described above, this utility model has the following advantages:

[0019] This invention utilizes an elastic element between the inner sleeve and the piston to drive the piston in reciprocating motion, thereby adaptively adjusting the flow area of ​​the nozzle. This allows the flow area to change dynamically with variations in the nozzle's working pressure and the gas medium flow rate, thus stabilizing the gas medium injection velocity at the nozzle, reducing fluctuations in the injection velocity, and maintaining a stable gas medium injection distribution. This, in turn, stabilizes the gas medium flow field distribution within the reduction furnace, ensuring a higher product yield under different operating conditions. This invention is suitable for widespread promotion and application. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model;

[0021] Figure 2 This is a schematic diagram of the first structure of the vent in this utility model;

[0022] Figure 3 This is a schematic diagram of the second structure of the vent in this utility model;

[0023] Figure 4 This is a schematic diagram of the third structure of the vent in this utility model;

[0024] Figure 5 This is a schematic diagram of the gas flow direction of this utility model;

[0025] Figure 6 This is a schematic diagram illustrating the working principle of this utility model;

[0026] Figure 7 This is a three-dimensional structural diagram of the piston in this utility model;

[0027] Figure 8 This is a schematic diagram of the first mating structure between the piston and the outer shell in this utility model;

[0028] Figure 9 This is a schematic diagram of the second mating structure between the piston and the outer shell in this utility model;

[0029] Figure 10 This is a schematic diagram of the third mating structure between the piston and the outer shell in this utility model;

[0030] Figure 11 This is a schematic diagram illustrating the application of this utility model;

[0031] In the diagram: 1. Piston; 2. Outer shell; 3. Elastic element; 4. Inner sleeve; 5. End cap; 6. Air guide hole; 7. Vent hole; 8. Gas medium; 9. Normal force; 10. Axial force; 11. Narrowing; 12. Raw material main pipe; 13. Branch pipe; 14. Waste gas discharge port; 15. Reduction furnace bottom; 16. Silicon core; 17. Polycrystalline silicon rod; 18. Reduction furnace hood. Detailed Implementation

[0032] The present invention can be explained in more detail through the following embodiments, but the present invention is not limited to the following embodiments;

[0033] First, it should be noted that the orientations or positional relationships indicated by terms such as "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer" used in describing the structure of this utility model are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of description and simplification, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0034] Combined with appendix Figures 1-11 The present invention relates to an adaptive feed nozzle for a polycrystalline silicon reduction furnace, comprising a piston 1, a shell 2, an elastic element 3, an inner sleeve 4, and an end cap 5. The inner sleeve 4 has a circular annular structure. Figure 1As shown, an end cap 5 is provided at the lower end of the inner hole in the middle of the inner sleeve 4. The end cap 5 seals the lower end of the inner hole in the middle of the inner sleeve 4. An elastic element 3 is provided on the top of the end cap 5. A piston 1 is provided above the elastic element 3. The lower end of the piston 1 is located above the inner hole in the middle of the inner sleeve 4. The piston 1 moves up and down in the inner hole in the middle of the inner sleeve 4 through the elastic element 3. At least one air guide hole 6 is provided in the middle of the piston 1. An outwardly extending ring is provided in the middle of the outer edge surface of the inner sleeve 4. A plurality of through air holes 7 are provided at intervals on the top of the ring. The outer edge surface of the ring is inserted into and fixed in the inner hole of the outer shell 2. A constriction 11 is provided at the upper end of the inner hole of the outer shell 2. The upper end of the piston 1 is located in the constriction 11. A gap is left between the inner edge surface of the constriction 11 and the outer edge surface of the piston 1, and the gap forms a nozzle. The lower end of the inner hole of the outer shell 2 is connected to the air inlet on the furnace bottom 15 of the reduction furnace.

[0035] Furthermore, in conjunction with the appendix Figure 1 , 5 As shown in Figures 6 and 7, the outer edge of the lower end of the piston 1 is provided with an outwardly extending lower annular boss.

[0036] Furthermore, in conjunction with the appendix Figure 1 , 5 As shown in Figures 6 and 7, the inner edge of the upper end of the inner hole in the middle of the inner sleeve 4 is provided with an inwardly extending upper annular boss.

[0037] During implementation, in conjunction with the appendix Figure 1 , 5 As shown in Figure 6, the piston 1 can be limited during its reciprocating motion by the cooperation of the upper and lower annular bosses, that is, the piston 1 can reciprocate up and down in the inner sleeve 4.

[0038] Furthermore, in practice, the elastic element 3 is a spring.

[0039] Furthermore, in conjunction with the appendix Figure 2 , 3 As shown in Figure 4, the shape of the vent 7 is circular, elliptical, or oblong (as shown in the attached figure). Figure 3 (as shown) or any of the following: square or polygonal.

[0040] Furthermore, in practice, when the end cap 5 is connected to the lower end of the inner hole in the middle of the inner sleeve 4, the first structure is that the outer edge surface of the end cap 5 is provided with an external thread, and the inner edge surface of the lower end of the inner hole in the middle of the inner sleeve 4 is provided with an internal thread. The internal thread and the external thread are threaded together, and at least one set of screw holes is provided on the bottom of the end cap 5.

[0041] Furthermore, in practice, when the end cap 5 is connected to the lower end of the inner hole in the middle of the inner sleeve 4, the second structure is that the end cap 5 is welded to the lower end of the inner hole in the middle of the inner sleeve 4.

[0042] Furthermore, in conjunction with the appendix Figure 1 , 5 As shown in Figure 10, the outer edge of the upper end of the piston 1 is configured as a conical structure with a smaller upper end and a larger lower end, or the upper end of the piston 1 is configured as a hemispherical structure.

[0043] Furthermore, in conjunction with the appendix Figure 1 , 5 As shown in Figures 6, 8 to 10, the shape of the constricted opening 11 is a conical structure with a small opening at the top and a large opening at the bottom, or a hemispherical structure with a small opening at the top and a large opening at the bottom.

[0044] When implementing, such as Figure 8 As shown, when the outer edge of the upper end of piston 1 is set as a conical structure with a smaller upper end and a larger lower end, the shape of the constriction 11 can be set as a conical structure with a smaller upper opening and a larger lower opening; or as shown... Figure 9 As shown, when the outer edge of the upper end of piston 1 is set as a conical structure with a smaller upper end and a larger lower end, the shape of the constriction 11 can be set as a hemispherical structure with a smaller upper opening and a larger lower opening; or as shown in the figure. Figure 10 As shown, when the outer edge of the upper end of piston 1 is set as a hemispherical structure, the shape of the constriction 11 can be set as a hemispherical structure with a small opening at the upper end and a large opening at the lower end.

[0045] Furthermore, in conjunction with the appendix Figure 1 , 5 As shown in Figures 6, 8 to 10, the outer edge of the upper end of the outer shell 2 is configured as a tapered structure with a smaller upper end and a larger lower end.

[0046] In specific implementation, this invention is combined with the appendix Figure 11 The reduction furnace mainly includes a furnace bottom 15 and a furnace cover 18. The furnace cover 18 is provided above the furnace bottom 15 to form a closed cavity. Multiple stacked silicon cores 16 are provided in the closed cavity. A waste gas exhaust port 14 is provided on the furnace bottom 15. When the gas medium 8 enters the cavity, the gas medium 8 continuously adheres to the outer surface of the silicon core 16, thereby forming the required polycrystalline silicon rod 17. The structure of the reduction furnace is a conventional structure in the field and will not be described in detail here.

[0047] When this utility model is in working condition, in conjunction with the attached... Figure 5 , 611. The nozzle is fixedly installed on the furnace bottom 15 of the reduction furnace by threads or other connection methods and is connected to the air inlet on the furnace bottom. The gas medium 8 enters each branch pipe 13 in the gas phase through the raw material main pipe 12. Each branch pipe 13 carries the gas medium 8 through the air inlet on the furnace bottom to each nozzle. After the gas medium 8 enters the inner cavity of the outer shell 2, it moves towards the outlet through the vent hole 7 set on the inner sleeve 4 under the drive of the working pressure. When it reaches the outlet, due to the internal pressure of the gas, it will act on the outer wall of the front end of the piston 1, forming an axial force 10 and a normal force 11. The axial force 10 will cause the piston 1 to move downward. At the same time, the lower end of the elastic element 3 is restricted by the fixed end cap 5 and can only move synchronously with the piston 1 in the manner of the upper end moving. As the reduction furnace operates, changes in the feed rate (i.e., the amount of gas medium 8 introduced) lead to changes in the feed pressure and flow rate. Consequently, the internal pressure acting on the outer wall of the piston 1 also changes. When this pressure changes, the piston 1 reciprocates, dynamically adjusting the nozzle flow area of ​​the gas medium 8 feed nozzle. This allows the nozzle flow area to change dynamically with variations in the nozzle's working pressure and flow rate. Simultaneously, the elastic element 3 adaptively matches the nozzle flow area to the feed pressure and flow rate, thereby stabilizing the gas medium injection velocity at the nozzle, reducing fluctuations in the injection velocity, and stabilizing the gas medium injection distribution. This, in turn, stabilizes the gas medium flow field distribution within the reduction furnace, ensuring a high product yield under different operating conditions.

[0048] Furthermore, in conjunction with the appendix Figure 5 , 6 7. Regarding the piston 1 described in this utility model, since its lower end is in the high-pressure area of ​​the gas medium 8 in the inner cavity of the outer shell 2 and its upper end is in the low-pressure area of ​​the gas outlet during operation, due to the pressure difference between its two ends, the piston 1 is always in a state of being "pushed upwards", making it difficult for it to be "pushed downwards" by the internal pressure thrust of the gas medium 8. Therefore, a plurality of air guide holes 6 are provided on the piston 1 to connect the pressure areas at the upper and lower ends of the piston 1, thereby strengthening the thrust of the internal pressure thrust of the gas medium 8 on the piston 1 and enhancing the effect of reciprocating motion, which is to achieve the effect of stabilizing the spray outlet speed of the nozzle.

[0049] This utility model has the following advantages:

[0050] 1. This utility model adopts an adaptive adjustment spray structure with elastic element 3, which can adjust the nozzle flow area according to the change of flow conditions, thereby avoiding the problem of large changes in the distribution of medium in the reduction furnace and unstable working state caused by the existing fixed nozzle structure.

[0051] 2. This utility model has the characteristics of simple structure, few parts, stable operation, and is not prone to failure due to damage to parts.

[0052] 3. The component assembly structure adopted in this utility model does not have complicated process requirements, the components are easy to replace, and if damaged, they can be replaced immediately and put into use, which is convenient for maintenance.

[0053] 4. This utility model can adopt the same connection structure as existing nozzles, making it convenient to install and use, and suitable for widespread promotion and application.

[0054] The parts of this utility model not described in detail are existing technologies.

[0055] The embodiments selected herein for the purpose of disclosing the inventive objectives of this invention are currently considered appropriate; however, it should be understood that this invention is intended to include all variations and modifications of the embodiments that fall within the scope of this concept and invention.

Claims

1. An adaptive feed nozzle for a polysilicon reduction furnace, comprising a piston (1), a housing (2), an elastic element (3), an inner sleeve (4), and an end cap (5), characterized in that: The inner sleeve (4) has a circular structure. An end cap (5) is provided at the lower end of the inner hole in the middle of the inner sleeve (4). The end cap (5) seals the lower end of the inner hole in the middle of the inner sleeve (4). An elastic element (3) is provided on the top of the end cap (5). A piston (1) is provided above the elastic element (3). The lower end of the piston (1) is located above the inner hole in the middle of the inner sleeve (4). The piston (1) moves up and down in the inner hole in the middle of the inner sleeve (4) through the elastic element (3). At least one air guide hole (6) is provided in the middle of the piston (1). An outwardly extending ring is provided in the middle of the outer edge of the inner sleeve (4). A plurality of through-holes (7) are provided on the upper part of the ring. The outer edge of the ring is inserted into and fixed in the inner hole of the outer shell (2). A constriction (11) is provided at the upper end of the inner hole of the outer shell (2). The upper end of the piston (1) is located in the constriction (11) and there is a gap between the inner edge of the constriction (11) and the outer edge of the piston (1) and the gap forms a nozzle. The lower end of the inner hole of the outer shell (2) is connected to the air inlet on the bottom (15) of the reduction furnace.

2. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The piston (1) has an outwardly extending lower annular boss on the outer edge of its lower end.

3. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The inner edge of the upper end of the inner hole in the middle of the inner sleeve (4) is provided with an inwardly extending upper annular boss.

4. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The elastic element (3) is a spring.

5. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The shape of the vent (7) can be any one of the following: circular, elliptical, oblong, square, or polygonal.

6. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The first structure when the end cap (5) is connected to the lower end of the inner hole in the middle of the inner sleeve (4) is that the outer edge surface of the end cap (5) is provided with an external thread, the inner edge surface of the lower end of the inner hole in the middle of the inner sleeve (4) is provided with an internal thread, the internal thread is threaded with the external thread, and at least one set of screw holes is provided on the bottom of the end cap (5).

7. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The second structure when the end cap (5) is connected to the lower end of the inner hole in the middle of the inner sleeve (4) is that the end cap (5) is welded to the lower end of the inner hole in the middle of the inner sleeve (4).

8. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The outer edge of the upper end of the piston (1) is set as a conical structure with a smaller upper end and a larger lower end, or the upper end of the piston (1) is set as a hemispherical structure.

9. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The shape of the constriction (11) is a conical structure with a small opening at the top and a large opening at the bottom, or a hemispherical structure with a small opening at the top and a large opening at the bottom.

10. The adaptive feed nozzle for a polycrystalline silicon reduction furnace according to claim 1, characterized in that: The outer edge of the upper end of the outer shell (2) is set as a tapered structure with a smaller upper end and a larger lower end.

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