A new bullet-shaped graphite head and graphite assembly

Abstract

The utility model discloses a novel bullet -like graphite head and graphite subassembly belong to polycrystalline silicon production technical field, including the main part of integrated forming, the main part includes the first frustum and second frustum that the outer contour is the frustum, and the outer diameter of first frustum and second frustum gradually reduces from the middle part to both sides, and the maximum outer diameter of first frustum is greater than the maximum outer diameter of second frustum, the minimum outer diameter of first frustum is not less than the minimum outer diameter of second frustum, and the junction of first frustum and second frustum forms annular step, solve the graphite head of bullet -like in prior art after first use, and the taper surface of silicon rod contact can appear serious silicon accumulation phenomenon, lead to its only disposable use, can not realize repeated use through reversal, lead to the consumption of graphite head is big, and the problem of high cost.

Description

Technical Field

[0001] This utility model belongs to the field of polycrystalline silicon production technology, specifically relating to a novel bullet-shaped graphite head and graphite assembly. Background Technology

[0002] Polycrystalline silicon is a primary raw material for the production of semiconductors and solar photovoltaic products. Currently, the main methods for producing polycrystalline silicon include the modified Siemens process, the silane process, and the fluidized bed process. The modified Siemens process and the silane process both require a deposition carrier during the reduction process. The modified Siemens process widely uses silicon cores as the carrier, including square and round silicon cores. The silicon core is connected and secured to the electrode using graphite modules. Graphite modules and silicon cores often experience failures due to factors such as processing precision, quality, and structure. For example, poor adhesion between the graphite substrate and the silicon core can cause bright spots and inverted silicon rods; conversely, if the graphite substrate and the silicon grown on it fail to bond together during production, it can cause cracking at the root of the silicon rod.

[0003] Traditional graphite assemblies used in polycrystalline silicon reduction furnaces mainly exist in two structural forms: one is a three-piece graphite assembly, consisting of a graphite base, a graphite nut, and a graphite retaining flap; the other is a two-piece graphite assembly, comprising a graphite base and a graphite bullet head. Taking patent document application number "202021560307.4" published on April 6, 2021, as an example, it discloses a specific graphite bullet head structure.

[0004] In existing technologies, graphite bases and graphite bullets often employ a socket-type connection structure: the graphite base has a conical hole at its upper end, and both ends of the graphite bullet are conical structures that mate with the conical holes in the graphite base. By pressing the graphite bullet, a fixed connection between the graphite base and the graphite bullet can be achieved while clamping the silicon core, making this installation method convenient. However, practical use shows that after the first use, the conical surface of the graphite bullet with this structure experiences severe silicon buildup on the surface that contacts the silicon rod, rendering it usable only once and unable to be reused by reversing its orientation. Processing the conical surface to remove the accumulated silicon layer results in problems such as excessive gap between the bullet and the graphite base, and dimensional mismatch between the graphite bullet and the graphite base. Utility Model Content

[0005] The present invention aims to solve the problem that in the prior art, the cone surface of the bullet-shaped graphite head that contacts the silicon rod will have severe silicon accumulation after the first use, which means that it can only be used once and cannot be reused by reversing the direction, resulting in a large consumption of graphite heads and high cost.

[0006] To achieve the above-mentioned objectives, the technical solution of this utility model is as follows:

[0007] A novel bullet-shaped graphite head includes an integrally formed body. The body includes a first truncated cone and a second truncated cone with an outer contour in the shape of a truncated cone. The outer diameters of the first truncated cone and the second truncated cone gradually decrease from the middle to the sides. The maximum outer diameter of the first truncated cone is greater than the maximum outer diameter of the second truncated cone, and the minimum outer diameter of the first truncated cone is not less than the minimum outer diameter of the second truncated cone. An annular step is formed at the junction of the first truncated cone and the second truncated cone.

[0008] Furthermore, the first cone has an axially extending silicon core hole at its top, the second cone has an axially penetrating exhaust channel that is coaxially connected to the silicon core hole, and an radially extending exhaust hole is provided at the annular step, with the exhaust hole connected to the exhaust channel.

[0009] Furthermore, the diameter of the silicon core hole is larger than the diameter of the exhaust channel.

[0010] Furthermore, the silicon core hole is a stepped hole.

[0011] Furthermore, the silicon core hole and the exhaust channel are connected through a variable diameter hole, the diameter of which gradually decreases from the silicon core hole toward the exhaust channel.

[0012] A graphite assembly includes a novel bullet-shaped graphite head and a graphite seat as described above. The top of the graphite seat is provided with a conical hole. The main body is installed in the conical hole on the upper part of the graphite seat through a second conical truncated cone. The outer surface of the second conical truncated cone is fitted with the inner surface of the conical hole, and the dimensions of the second conical truncated cone and the conical hole are mutually adapted.

[0013] Furthermore, the bottom of the graphite base is provided with an electrode receiving cavity for accommodating the electrode.

[0014] The beneficial effects of this utility model are:

[0015] I. This utility model proposes a novel bullet-shaped graphite head structure. Compared with the traditional bullet-shaped graphite head structure, the first and second truncated cones on the main body of this design are different structures. The outer diameters of the first and second truncated cones gradually decrease from the middle to both sides, and the maximum outer diameter of the first truncated cone is greater than that of the second truncated cone, as are the minimum outer diameters. This allows the first truncated cone to be machined to the same size as the second truncated cone after the first use, removing surface silicon and excess graphite, ensuring that the machined surface of the first truncated cone is smooth and free of silicon accumulation, and that it matches the size of the conical hole in the lower graphite seat. This structural design enables the second reuse of the graphite head, reducing the use of graphite heads and lowering the risk of pressure failure or furnace collapse caused by graphite heads.

[0016] II. This utility model proposes a novel bullet-shaped graphite head structure. The inner diameter of the exhaust channel in the second cone of the original bullet-shaped graphite head is designed to be smaller than the size of the silicon core hole. Before the second use, it is machined to the size of the silicon core hole, ensuring that the conical surface where the silicon core hole contacts the silicon core is smooth and free of silicon buildup. Compared to the traditional structure where both ends are designed as silicon core holes, this structure avoids the problem of a small amount of silicon buildup in the exhaust channel of the second cone during the first use. This buildup leads to a rough surface on the graphite bullet head and a rough silicon core hole, which can cause poor contact between the silicon core and the graphite bullet head if the head is used again to install a silicon core, resulting in pressure testing failure or furnace collapse.

[0017] Third, this utility model also proposes a preferred graphite assembly, including a novel bullet-shaped graphite head and a graphite seat. The size of the conical surface of the second truncated cone of the graphite head is adapted to the size of the conical hole of the graphite seat to meet production requirements. After machining, the first truncated cone of the graphite head should also be the same as the conical surface of the second truncated cone to facilitate matching with the size of the conical surface of the truncated cone. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a new type of bullet-shaped graphite head.

[0019] Figure 2 This is a schematic diagram of the structure of a novel bullet-shaped graphite head after machining.

[0020] Figure 3 This is a schematic diagram of a novel bullet-shaped graphite head installed in a graphite base.

[0021] Among them, 1. main body; 2. first truncated cone; 3. second truncated cone; 4. silicon core hole; 5. annular step; 6. exhaust channel; 7. exhaust hole; 8. variable diameter hole; 9. graphite seat; 10. conical hole; 11. electrode receiving cavity. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0023] Example 1

[0024] This embodiment is the most basic implementation method, a novel bullet-shaped graphite head, see reference. Figure 1 The system includes an integrally formed main body 1, which includes a first frustum 2 and a second frustum 3 with an outer contour in the shape of a frustum. The outer diameters of the first frustum 2 and the second frustum 3 gradually decrease from the middle to both sides. The maximum outer diameter of the first frustum 2 is greater than the maximum outer diameter of the second frustum 3, and the minimum outer diameter of the first frustum 2 is not less than the minimum outer diameter of the second frustum 3. An annular step 5 is formed at the junction of the first frustum 2 and the second frustum 3.

[0025] When this novel bullet-shaped graphite head is used for the first time, its second cone 3 is inserted into the graphite seat 9, and the silicon core hole 4 on the main body 1 is used to receive the silicon core. After the graphite head is used once, it is uniformly recycled. Then, the conical surface of the first cone 2 of the recycled graphite head that contacts the silicon rod is machined a second time according to the conical surface of the second cone 3 of the graphite head. At the same time, the exhaust channel 6 of the second cone 3 is re-machined and opened according to the size of the silicon core hole 4. The processed structure is shown in the reference. Figure 2 This allows the new bullet-shaped graphite head to be reprocessed and reused after use.

[0026] Example 2

[0027] The difference between this embodiment and Embodiment 1 is that, in reference to Figure 1 The first cone 2 has a silicon core hole 4 extending axially at its top, the second cone 3 has an exhaust channel 6 that extends axially and is coaxially connected with the silicon core hole 4, and an exhaust hole 7 extending radially is provided at the annular step 5, the exhaust hole 7 being connected to the exhaust channel 6.

[0028] Example 3

[0029] The difference between this embodiment and embodiments 1-2 is that, in reference to... Figure 1 The diameter of the silicon core hole 4 is larger than the diameter of the exhaust channel 6.

[0030] Example 4

[0031] The difference between this embodiment and embodiments 1-3 is that, in reference... Figure 1 The silicon core hole 4 is a stepped hole.

[0032] Example 5

[0033] The difference between this embodiment and embodiments 1-4 is that, in reference to Figure 1 The silicon core hole 4 and the exhaust channel 6 are connected through a variable diameter hole 8, and the diameter of the variable diameter hole 8 gradually decreases from the silicon core hole 4 toward the exhaust channel 6.

[0034] Example 6

[0035] To facilitate public understanding of this utility model, this embodiment uses a preferred graphite component as an example, and further explains the solution in conjunction with the illustrations.

[0036] refer to Figure 3 The graphite assembly includes a novel bullet-shaped graphite head and a graphite seat 9. The top of the graphite seat 9 is provided with a conical hole 10. The main body 1 of the novel bullet-shaped graphite head is installed in the conical hole 10 on the upper part of the graphite seat 9 through a second conical truncated cone 3. The outer surface of the second conical truncated cone 3 is in contact with the inner surface of the conical hole 10. The dimensions of the second conical truncated cone 3 and the conical hole 10 are adapted to each other. The bottom of the graphite seat 9 is provided with an electrode receiving cavity 11 for accommodating electrodes.

[0037] The novel bullet-shaped graphite head includes an integrally formed body 1. The body 1 includes a first frustum 2 and a second frustum 3 with an outer contour in the shape of a frustum. The outer diameters of the first frustum 2 and the second frustum 3 gradually decrease from the middle to both sides. The maximum outer diameter of the first frustum 2 is greater than the maximum outer diameter of the second frustum 3, and the minimum outer diameter of the first frustum 2 is also greater than the minimum outer diameter of the second frustum 3. An annular step 5 is formed at the junction of the first frustum 2 and the second frustum 3.

[0038] In this embodiment, the top of the first cone 2 is provided with a silicon core hole 4 extending along the axis, the second cone 3 is provided with an exhaust channel 6 that extends along the axis and is coaxially connected with the silicon core hole 4, and an exhaust hole 7 extending along the radial direction is provided at the annular step 5, and the exhaust hole 7 is connected with the exhaust channel 6.

[0039] In this embodiment, the diameter of the silicon core hole 4 is larger than the diameter of the exhaust channel 6, and the silicon core hole 4 is a stepped hole.

[0040] In this embodiment, the silicon core hole 4 and the exhaust channel 6 are connected through a variable diameter hole 8, and the diameter of the variable diameter hole 8 gradually decreases from the silicon core hole 4 toward the exhaust channel 6.

[0041] In this embodiment, during the design of the graphite head, the diameter of the first frustum 2 in contact with the silicon rod is increased from φ40mm to φ45mm. After the graphite heads are used once, they are uniformly recycled. The conical surface of the first frustum 2 of the recycled graphite heads in contact with the silicon rod is then machined a second time according to the conical surface of the second frustum 3 of the graphite head to obtain a smooth conical surface without silicon accumulation. At the same time, the exhaust channel 6 of the second frustum 3 is re-machined and opened according to the size of the silicon core hole 4. The processed structure is referenced. Figure 2 Ensuring a smooth, silicon-free contact surface between the graphite head and the graphite base allows the new bullet-shaped graphite head to be reprocessed and reused after use. Simultaneously, the smooth, silicon-free contact surface between the silicon core hole 4 of the graphite head and the silicon core prevents poor contact between the silicon core and the graphite head, thus avoiding pressure failure or furnace collapse.

Claims

1. A novel bullet-shaped graphite head, characterized in that: The body (1) is integrally formed. The body (1) includes a first truncated cone (2) and a second truncated cone (3) with an outer contour in the shape of a truncated cone. The outer diameter of the first truncated cone (2) and the second truncated cone (3) gradually decreases from the middle to both sides. The maximum outer diameter of the first truncated cone (2) is greater than the maximum outer diameter of the second truncated cone (3), and the minimum outer diameter of the first truncated cone (2) is not less than the minimum outer diameter of the second truncated cone (3). The connection between the first truncated cone (2) and the second truncated cone (3) forms an annular step (5).

2. The novel bullet-shaped graphite head according to claim 1, characterized in that: The first cone (2) has a silicon core hole (4) extending axially at its top, the second cone (3) has an exhaust channel (6) that extends axially and is coaxially connected with the silicon core hole (4), and an exhaust hole (7) extending radially is provided at the annular step (5), and the exhaust hole (7) is connected with the exhaust channel (6).

3. A novel bullet-shaped graphite head according to claim 2, characterized in that: The diameter of the silicon core hole (4) is larger than the diameter of the exhaust channel (6).

4. A novel bullet-shaped graphite head according to claim 3, characterized in that: The silicon core hole (4) is a stepped hole.

5. A novel bullet-shaped graphite head according to claim 3, characterized in that: The silicon core hole (4) and the exhaust channel (6) are connected through a variable diameter hole (8), and the diameter of the variable diameter hole (8) gradually decreases from the silicon core hole (4) towards the exhaust channel (6).

6. A graphite component, characterized in that: The novel bullet-shaped graphite head and graphite seat (9) as described in claim 1 are provided. The top of the graphite seat (9) is provided with a conical hole (10). The main body (1) is installed in the conical hole (10) on the upper part of the graphite seat (9) through a second conical truncated cone (3). The outer surface of the second conical truncated cone (3) is in contact with the inner surface of the conical hole (10). The dimensions of the second conical truncated cone (3) and the conical hole (10) are adapted to each other.

7. A graphite assembly according to claim 6, characterized in that: The bottom of the graphite base (9) is provided with an electrode receiving cavity (11) for accommodating the electrode.

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