Novel intermediate exhaust thermal field for single crystal furnace and single crystal furnace

Abstract

The utility model provides a novel middle exhaust thermal field for a single crystal furnace and the single crystal furnace, the middle exhaust thermal field comprises a crucible, a guide cylinder, a heat preservation cylinder, a heater and a graphite electrode, the bottom end of the heater is provided with a heater pin used for connecting the graphite electrode, the air inlet end of a middle exhaust component is located above the graphite electrode, and the air outlet end of the middle exhaust component is located above the graphite electrode. And the air outlet end is connected with the air extracting pump. Through the air inlet pipe arranged at the bottom edge of the heater, hot air is quickly discharged, the hot air guiding and discharging efficiency is improved, deposition of oxides in the hot air on the heater is reduced, corrosion to blades of the heater is reduced, hot air flowing to the bottom end of the heater foot and a graphite electrode is reduced, and deposition of the oxides in the hot air at the bottom end of the heater foot and the graphite electrode is reduced; the ignition risk of the heater is reduced, the service life of equipment is prolonged, and the equipment maintenance cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic production, in particular to a novel center exhaust thermal field for a single crystal furnace and a single crystal furnace. Background Art

[0002] A single crystal furnace is a device that uses a graphite heater to melt polycrystalline materials such as polysilicon in an inert gas environment and grow dislocation-free single crystals using the Czochralski method. The production process for a single crystal furnace is generally as follows: a certain amount of polycrystalline silicon raw material is placed in a crucible and heated until melted. A seed crystal is clamped at the lower end of a pull rod and immersed in the molten crystal raw material. The pull rod is then slowly pulled upward while rotating, ultimately growing a cylindrical single crystal silicon rod.

[0003] The thermal field of a single crystal furnace generally includes a crucible, a guide tube, an insulation tube, a heater, a graphite electrode and other auxiliary structures, and usually adopts a downward exhaust method, that is, an exhaust riser is set directly below the thermal field, and the exhaust riser is used to discharge the hot gas in the single crystal furnace. However, in the process of the hot gas flowing downward along the heater and entering the exhaust pipe, due to the long flow path and slow flow rate, some oxides in the hot gas will be deposited on the heater. When the hot gas flows through the heater foot, some oxides in the hot gas will adhere to the space between the heater foot and the electrode column, causing abnormal ignition of the electrode column, shortening the service life of the heater and increasing its maintenance cost. Utility Model Content

[0004] The purpose of the utility model is to provide a new type of middle exhaust heat field and single crystal furnace for a single crystal furnace, so as to solve the problems in the above background.

[0005] The technical solution adopted by the utility model is: a new type of central exhaust thermal field for a single crystal furnace, comprising a crucible, a guide tube, an insulation tube, a heater and a graphite electrode, wherein: the bottom end of the heater is provided with a heater foot for connecting the graphite electrode, the air inlet end of the central exhaust component is located above the graphite electrode, and the air outlet end is connected to the vacuum pump.

[0006] Furthermore, the middle exhaust assembly includes a manifold, an air inlet pipe and an air outlet pipe, the manifold extends in the same direction as the heater, and there are several air inlet pipes distributed along the axial direction of the manifold, and the axis of at least some of the air inlet pipes forms an acute angle with the axis of the manifold, and the air outlet pipe is located at the bottom of the manifold and is connected to the vacuum pump at one end away from the manifold.

[0007] Furthermore, the air inlet pipe located at the top of the manifold extends horizontally, and its top is flush with the bottom edge of the heater; the other air inlet pipes are equidistantly distributed along the axial direction of the manifold, with their top ends facing the heater and their bottom ends facing the manifold.

[0008] Furthermore, the included angle between the axis of at least part of the air inlet pipe and the axis of the manifold is 30° to 60°.

[0009] Furthermore, the inner diameter ratio of the air intake pipe located at the top end of the manifold to the other air intake pipes is (1-1.5):1.

[0010] Furthermore, the air outlet pipe is L-shaped, and the air pump is located at the bottom of the vertical end portion thereof.

[0011] Furthermore, the outer wall of the middle exhaust assembly is provided with a thermal insulation felt, and the outer wall surface of the thermal insulation felt is also provided with a protective pad, which is wrapped around the thermal insulation felt.

[0012] Furthermore, a plurality of groups of the middle exhaust components are arranged around the outer periphery of the heater, and each group of the heater legs corresponds to at least one group of the middle exhaust components.

[0013] The technical solution of the present invention also includes: a single crystal furnace, which includes the novel center exhaust thermal field for the single crystal furnace as described above.

[0014] The beneficial effects of the utility model are as follows: through the air inlet pipe arranged at the bottom edge of the heater, the hot air is quickly discharged, the hot air exhaust efficiency is improved, the deposition of oxides in the hot air on the heater is reduced, the corrosion of the heater blades is reduced, and the hot air flowing to the bottom end of the heater and the graphite electrode is reduced, the deposition of oxides in the hot air there is reduced, the risk of ignition of the heater is reduced, the service life of the equipment is extended, and the equipment maintenance cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an overall structural diagram of an embodiment of the utility model;

[0016] Figure 2 This utility model embodiment is attached Figure 1 A magnified view of the structure in the middle.

[0017] In the picture:

[0018] 1. Crucible;

[0019] 2. Guide tube;

[0020] 3. Heater;

[0021] 4. Heater feet;

[0022] 5. Graphite electrode;

[0023] 6. Middle exhaust assembly; 6.1. Manifold; 6.2. Inlet pipe; 6.3. Outlet pipe;

[0024] 7. Air pump;

[0025] 8. Install the insulation tube;

[0026] 9. Middle insulation cylinder;

[0027] 10. Lower insulation cylinder;

[0028] 11. Thermal insulation felt;

[0029] 12. Protective pad. DETAILED DESCRIPTION

[0030] The technical solutions of the embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0031] In the description of the embodiments of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "setting" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood based on specific circumstances.

[0032] Reference Attachment Figure 1-2 The present embodiment provides a new type of middle exhaust heat field for a single crystal furnace, which includes a crucible 1, a guide tube 2, a heat preservation tube, a heater 3, a graphite electrode 5, a middle exhaust assembly 6 and an exhaust pump 7. The crucible 1 is supported on the inner bottom of the single crystal furnace body by a crucible support rod and a crucible tray. The guide tube 2 extends from the top opening of the crucible 1 to the inside of the crucible 1. The heater 3 is arranged around the outside of the crucible 1. The bottom end of the heater 3 is provided with a heater foot 4. The heater foot 4 is used to connect the graphite electrode 5. When the graphite electrode After the power is connected and the ignition is ignited, the heater 3 starts heating. The insulation tube is arranged between the inner wall of the single crystal furnace body and the outer wall of the heater 3, and includes an upper insulation tube 8, a middle insulation tube 9, and a lower insulation tube 10 connected in sequence. The bottom edge of the middle insulation tube 9 is lower than the bottom edge of the heater 3 and higher than the bottom edge of the heater foot 4. The middle exhaust assembly 6 is arranged on the outside of the insulation tube. Its air inlet end passes through the portion of the middle insulation tube 9 that is flush with the bottom edge of the heater 3, and its air outlet end is connected to the air extraction pump 7 located below the heater foot 4.

[0033] Specifically, the middle exhaust assembly 6 is a combination of pipes, which is used to quickly conduct the hot air flowing through the heater 3 to the outside of the single crystal furnace to prevent the oxides in the hot air from being deposited on the heater 3 or between the heater foot 4 and the graphite electrode 5. The middle exhaust assembly 6 specifically includes a manifold 6.1, an air inlet pipe 6.2 and an air outlet pipe 6.3. The manifold 6.1 extends in the same direction as the heater 3, that is, the axis is parallel. There are one or more air inlet pipes 6.2 distributed along the axial direction of the manifold 6.1. The air outlet pipe 6.3 is located at the bottom of the manifold 6.1, and its end away from the manifold 6.1 is connected to the vacuum pump 7. When there is only one air inlet pipe 6.2, the air inlet pipe 6.2 is located at the top of the manifold 6.1, extends horizontally and the top is aligned with the bottom edge of the heater 3. When there are multiple air inlet pipes 6.2, the air inlet pipe 6.2 located at the top of the manifold 6.1 extends horizontally and the top is aligned with the bottom edge of the heater 3. The other air inlet pipes 6.2 are arranged obliquely, with their axes forming an acute angle with the axis of the manifold 6.1, and their top ends facing the heater 3 and their bottom ends facing the manifold 6.1, so as to help discharge the residual hot air below the bottom edge of the heater 3 and above the heater foot 4. With the assistance of the vacuum pump 7, the hot air is prevented from entering the manifold 6.1 through the upper air inlet pipe 6.2 and then flowing back to the bottom of the heater 3 through the lower air inlet pipe 6.2, thereby depositing oxide between the heater foot 4 and the graphite electrode 5.

[0034] To improve the flow guidance effect, the air inlet pipes 6.2 can be distributed equidistantly along the axial direction of the manifold 6.1, the angle between the axis of the air inlet pipe 6.2 and the axis of the manifold 6.1 is controlled to be between 30° and 60°, and the inner diameter ratio of the air inlet pipe 6.2 located at the top of the manifold 6.1 to the other air inlet pipes 6.2 is controlled to be (1~1.5):1.

[0035] In this embodiment, in order to minimize the structural modification and interference to the original thermal field, the outlet pipe 6.3 is configured in an L shape, with its horizontal end connected to the bottom of the manifold 6.1 and the bottom end of the vertical end connected to the air pump 7.

[0036] Because the intake pipe 6.2 of the middle exhaust assembly 6 passes through the middle insulation tube 9 and may affect its insulation performance, this embodiment incorporates insulation felt 11 on the outer walls of all pipes in the middle exhaust assembly 6 to minimize any impact on the insulation performance of the insulation tube. Protective pads 12 can also be placed on the outer walls of the insulation felt 11, wrapping around it to prevent burns from the insulation felt 11 during maintenance. Graphite carbon felt can be used for the insulation felt 11.

[0037] In order to improve the exhaust efficiency, several groups of middle exhaust components 6 can be arranged around the outer periphery of the heater 3. Generally, two groups of heater feet 4 are provided at the bottom of the heater 3. Therefore, it should be ensured that each group of heater feet 4 corresponds to at least one group of middle exhaust components 6 to minimize the hot gas from bringing oxides to the contact area between the heater feet 4 and the graphite electrode 5.

[0038] This embodiment also provides a single crystal furnace, which is equipped with the novel middle exhaust heat field for the single crystal furnace as described above, and has good exhaust and oxide deposition prevention effects.

[0039] Compared with the prior art, the beneficial effects of the present invention are: through the air intake pipe 6.2 arranged at the bottom edge of the heater 3, the hot air is quickly discharged, the hot air exhaust efficiency is improved, the deposition of oxides in the hot air on the heater 3 is reduced, the corrosion of the blades of the heater 3 is reduced, and the hot air flowing to the bottom end of the heater foot 4 and the graphite electrode 5 is reduced, the deposition of oxides in the hot air there is reduced, the risk of ignition of the heater 3 is reduced, the service life of the equipment is extended, and the equipment maintenance cost is reduced.

[0040] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A new type of exhaust gas heat field for a single crystal furnace, comprising a crucible, a guide tube, a heat preservation tube, a heater and a graphite electrode, characterized in that: It also includes a middle exhaust component and an air pump. The bottom end of the heater is provided with a heater foot for connecting to the graphite electrode. The air inlet end of the middle exhaust component is located above the graphite electrode, and the air outlet end is connected to the air pump.

2. The novel middle exhaust heat field for single crystal furnace according to claim 1 is characterized in that: The middle exhaust assembly includes a manifold, an air inlet pipe and an air outlet pipe. The manifold extends in the same direction as the heater. There are several air inlet pipes distributed along the axial direction of the manifold. The axis of at least some of the air inlet pipes forms an acute angle with the axis of the manifold. The air outlet pipe is located at the bottom of the manifold and is connected to the air pump at one end away from the manifold.

3. The novel middle exhaust heat field for single crystal furnace according to claim 2 is characterized in that: The air inlet pipe at the top of the manifold extends horizontally, with its top aligned with the bottom edge of the heater; the other air inlet pipes are equidistantly distributed along the axial direction of the manifold, with their tops facing the heater and their bottoms facing the manifold.

4. The novel middle exhaust thermal field for single crystal furnace according to claim 2 or 3, characterized in that: The included angle between the axis of at least part of the air inlet pipe and the axis of the manifold is 30° to 60°.

5. The novel middle exhaust heat field for single crystal furnace according to claim 4 is characterized in that: The inner diameter ratio of the air intake pipe at the top end of the manifold to the other air intake pipes is (1-1.5):

1.

6. The novel middle exhaust thermal field for single crystal furnace according to claim 2, characterized in that: The air outlet pipe is L-shaped, and the air pump is located at the bottom of the vertical end portion thereof.

7. The novel central exhaust thermal field for a single crystal furnace according to any one of claims 1-3, 5-6, characterized in that: The outer wall of the middle exhaust assembly is provided with a thermal insulation felt, and the outer wall surface of the thermal insulation felt is also provided with a protective pad which is wrapped around the thermal insulation felt.

8. The novel central exhaust heat field for single crystal furnace according to claim 6, characterized in that: The middle exhaust components are arranged in a plurality of groups around the outer periphery of the heater, and each group of the heater legs corresponds to at least one group of the middle exhaust components.

9. A single crystal furnace, characterized in that: The invention comprises the novel central exhaust thermal field for a single crystal furnace as described in any one of claims 1-8.

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