Multilayer thermal insulation structure and single crystal silicon thermal field device

Abstract

The utility model relates to monocrystal silicon preparation equipment technical field provides a kind of multilayer heat preservation structure and monocrystal silicon thermal field device, multilayer heat preservation structure includes by inside to outside sequentially arranged reflection layer, first heat preservation layer, second heat preservation layer and support layer;Wherein, the second heat preservation layer is equipped with the vacuum device being communicated with its inside on it.Vacuum device includes vacuum layer valve door interface and vacuum layer ball valve, the vacuum layer ball valve is connected to the second heat preservation layer by the vacuum layer valve door interface.The utility model sets up second heat preservation layer in multilayer heat preservation structure, and sets up vacuum device on second heat preservation layer, both can realize heat preservation effect, and can be quickly into cooling medium and realize cooling after shutdown, effectively shorten cooling time, improve production efficiency.Meanwhile, the oxidation loss of carbon fiber in multilayer heat preservation structure can be reduced by the rapid cooling function, prolong the service life of multilayer heat preservation structure.

Description

Technical Field

[0001] This utility model relates to the technical field of single crystal silicon preparation equipment, and in particular to a multi-layer heat insulation structure and a single crystal silicon thermal field device. Background Technology

[0002] In the preparation of monocrystalline silicon, the Czochralski method (Cz method) is currently the main method for producing photovoltaic-grade monocrystalline silicon. This method requires a high-temperature environment of 1412℃, and the entire thermal field system needs to be maintained by insulation felt. Traditional insulation felt typically uses a combination of hard and soft felt, with a soft felt with better thermal insulation properties in the inner layer and a hard felt with better mechanical properties in the outer layer. Existing technologies also include solutions that incorporate a vacuum layer inside the insulation cylinder or insulation felt. This vacuum layer reduces heat conduction and convection, thereby improving the insulation effect.

[0003] However, existing insulation felts suffer from a trade-off between insulation performance and furnace shutdown cooling efficiency. Specifically, when insulation performance is improved, the single-crystal furnace requires over 10 hours of natural cooling after shutdown before it can be disassembled, severely impacting production efficiency. While existing vacuum layer insulation solutions can improve insulation performance, they also increase the cooling time after furnace shutdown. Furthermore, due to prolonged contact with air at high temperatures, the carbon fibers within the insulation felt are prone to oxidation, leading to surface powdering and affecting both insulation effectiveness and service life.

[0004] These problems result in high energy consumption, low production efficiency, and short lifespan of insulation felt during the production of monocrystalline silicon, which severely restricts the efficiency and cost control of monocrystalline silicon production. Utility Model Content

[0005] The purpose of this invention is to provide a multi-layer insulation structure and a single-crystal silicon thermal field device to solve the technical problems of long heat dissipation time and short service life of insulation felt in the existing single-crystal furnace thermal field.

[0006] To achieve the above-mentioned utility model objectives, this utility model provides a multi-layer thermal insulation structure, comprising a reflective layer, a first thermal insulation layer, a second thermal insulation layer, and a support layer arranged sequentially from the inside to the outside.

[0007] The second insulation layer is equipped with a vacuum device that communicates with its interior.

[0008] Optionally, the vacuum device includes a vacuum layer valve interface and a vacuum layer ball valve, wherein the vacuum layer ball valve is connected to the second insulation layer through the vacuum layer valve interface.

[0009] Optionally, the vacuum layer ball valve includes:

[0010] Ball valve housing;

[0011] The internal rotating shaft of the ball valve is located inside the ball valve housing;

[0012] The ball valve knob is connected to the internal rotating shaft of the ball valve;

[0013] and the ball valve inlet and outlet provided on the ball valve housing;

[0014] The ball valve has a condensate flow channel on its internal rotating shaft, and one end of the condensate flow channel is connected to the inlet and outlet of the ball valve.

[0015] Optionally, the ball valve knob is provided with a threaded hole for connecting an external pipe.

[0016] Optionally, a ball valve sealing layer is provided at the mating point between the ball valve housing and the internal rotating shaft of the ball valve.

[0017] Optionally, by rotating the ball valve knob, the condensate flow channel is aligned with or offset from the vacuum layer valve interface, thereby opening or closing the vacuum layer ball valve.

[0018] Optionally, the reflective layer is a metal coating, which includes a molybdenum coating with a thickness of 3-7 mm.

[0019] Optionally, the thickness of the first insulation layer is 40-60mm; the thickness of the second insulation layer is 65-85mm; and the thickness of the support layer is 40-60mm.

[0020] Optionally, the vacuum layer ball valve is provided in two parts, one of which is connected to the feed pipe and the other is connected to the discharge pipe.

[0021] This utility model also provides a single-crystal silicon thermal field device, comprising:

[0022] Flow deflector;

[0023] A heat-insulating cylinder is disposed around the flow guide cylinder;

[0024] Quartz crucibles are used to hold silicon materials;

[0025] The main heater is positioned around the quartz crucible;

[0026] The crucible sidewalls support the side walls of the quartz crucible;

[0027] A crucible support, used to support the bottom of the quartz crucible;

[0028] A multi-layer insulation structure is installed in the outer area of ​​the thermal field;

[0029] A bottom heater is disposed in the bottom region of the single-crystal silicon thermal field device;

[0030] Support rods are used to support the entire device; and

[0031] Bottom insulation felt is installed in the bottom area;

[0032] The multi-layer insulation structure described above adopts the multi-layer insulation structure.

[0033] This invention improves the insulation effect and reduces the power consumption of the heater by setting a second insulation layer in the multi-layer insulation structure and equipping it with a vacuum device that connects to the second insulation layer. It also enables rapid cooling by injecting cooling medium through the vacuum device after the furnace is shut down, thus shortening the cooling waiting time and improving production efficiency.

[0034] The multi-layer insulation structure provided by this utility model adopts a multi-layer structural design. By reflecting heat radiation through a reflective layer, providing basic insulation performance through a first insulation layer, enhancing the insulation effect through a second insulation layer, and providing mechanical strength through a supporting layer, a unity of insulation performance and structural strength is achieved. At the same time, by providing a ball valve sealing layer at the contact point between the ball valve shell and the ball valve internal rotating shaft, and by providing a threaded hole on the ball valve knob for connecting external pipes, a structural foundation is provided for the sealing of the vacuum system and the injection of cooling medium, and the service life of the multi-layer insulation structure is extended. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the single-crystal silicon thermal field device in an embodiment of this utility model;

[0036] Figure 2 This is a schematic diagram of the multi-layer thermal insulation structure in an embodiment of this utility model;

[0037] Figure 3 This is a schematic plan view of the multi-layer thermal insulation structure in an embodiment of this utility model;

[0038] Figure 4 This is a schematic diagram of the vacuum layer ball valve in the open state in an embodiment of this utility model;

[0039] Figure 5 This is a schematic diagram of the vacuum layer ball valve in the closed state in an embodiment of this utility model.

[0040] In the diagram: 1. Flow guide tube; 2. Insulation tube; 3. Quartz crucible; 4. Main heater; 5. Crucible side; 6. Crucible support; 7. Multi-layer insulation structure; 8. Vacuum layer ball valve; 9. Bottom heater; 10. Support rod; 11. Bottom insulation felt;

[0041] 71. Reflective layer; 72. First insulation layer; 73. Second insulation layer; 74. Support layer; 75. Vacuum layer valve interface;

[0042] 81. Ball valve knob; 82. Ball valve inlet and outlet; 83. Ball valve sealing layer; 84. Condensate flow channel; 85. Ball valve housing; 86. Ball valve internal shaft. Detailed Implementation

[0043] The present invention will now be described with reference to the accompanying drawings, which illustrate preferred embodiments of the present invention. It should be understood that those skilled in the art can modify the present invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the present invention.

[0044] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element 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.

[0045] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0046] The present invention will be described in more detail below by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0047] Example 1

[0048] Please refer to Figure 1 , Figure 1The outer region of the thermal field shown is provided with the multi-layer insulation structure 7 provided in this embodiment to provide good insulation effect. A vacuum layer ball valve 8 is installed on the multi-layer insulation structure 7 to control the vacuuming and cooling process of the vacuum layer.

[0049] The bottom area of ​​the monocrystalline silicon thermal field device is equipped with a bottom heater 9 to regulate the temperature field distribution. The entire device is supported by a support rod 10, and a bottom insulation felt 11 is also provided in the bottom area to reduce heat loss.

[0050] This utility model provides a multi-layer heat insulation structure 7 for the hot zone of a single crystal furnace. Please refer to [reference needed]. Figure 1 - Figure 3 It includes a multi-layer structure arranged sequentially from the inside out. The multi-layer structure includes a reflective layer 71, a first heat insulation layer 72, a second heat insulation layer 73, and a support layer 74.

[0051] The second insulation layer 73 of the multi-layer insulation structure 7 is equipped with a vacuum device that communicates with its interior. The vacuum device is used to evacuate the second insulation layer 73 or to introduce a cooling medium.

[0052] Furthermore, the vacuum device includes a vacuum layer valve interface 75 and a vacuum layer ball valve 8, the vacuum layer ball valve 8 being connected to the second insulation layer 73 via the vacuum layer valve interface 75. The connection between the vacuum layer valve interface 75 and the vacuum layer ball valve 8 enables vacuuming or circulation of the cooling medium.

[0053] Furthermore, the reflective layer 71 is disposed on the innermost side for reflecting heat radiation. The first insulation layer 72 is disposed on the outer side of the reflective layer 71 for providing insulation performance. The second insulation layer 73 is disposed on the outer side of the first insulation layer 72, and the shell of the second insulation layer 73 is made of a high-temperature resistant material. The support layer 74 is disposed on the outer side of the second insulation layer 73, and together with the second insulation layer 73, provides mechanical support.

[0054] In a specific example, the reflective layer 71 and the first insulation layer 72 are bonded together with an adhesive. The thickness of the adhesive layer is controlled at 1-2 mm to ensure that there are no gaps between the reflective layer 71 and the first insulation layer 72, thus preventing heat loss.

[0055] The first insulation layer 72 and the second insulation layer 73 can be joined by mechanical pressing, and a high-temperature sealing material is applied to the contact surface to ensure the airtightness of the interface.

[0056] The second insulation layer 73 and the support layer 74 can be connected by a snap-fit ​​structure, and the two are fixed by a snap-fit ​​method, which is convenient for disassembly and separation during maintenance.

[0057] The vacuum layer valve interface 75 and the vacuum layer ball valve 8 are connected by threads and sealed with a high-temperature sealing ring. The sealing ring at the connection can be made of graphite composite material, which can maintain good sealing performance in high-temperature environments.

[0058] Please continue to refer to this. Figure 2 The second insulation layer 73 is provided with a vacuum layer ball valve 8 on its exterior. The vacuum layer ball valve 8 is used for evacuating a vacuum and introducing a cooling medium.

[0059] For details, please continue to refer to [the website / information]. Figure 3 The vacuum layer ball valve 8 includes: a ball valve housing 85; an internal ball valve shaft 86 disposed within the ball valve housing 85; a ball valve knob 81 connected to the internal ball valve shaft 86; and a ball valve inlet / outlet 82 disposed on the ball valve housing 85; wherein, a condensate water channel 84 is provided on the internal ball valve shaft 86, and one end of the condensate water channel 84 is connected to the ball valve inlet / outlet 82.

[0060] Furthermore, the ball valve knob 81 is provided with a threaded hole for connecting an external pipeline, through which an external pipeline can be easily connected.

[0061] Furthermore, to ensure a vacuum effect, a ball valve sealing layer is provided at the mating point between the ball valve housing 85 and the ball valve internal rotating shaft 86.

[0062] In this embodiment, please refer to Figure 4 - Figure 5 By rotating the ball valve knob 81, the condensate flow channel 84 is aligned with or offset from the vacuum layer valve interface 75, thereby opening or closing the vacuum layer ball valve 8.

[0063] In this embodiment, to reduce the size of the ball valve and avoid unnecessary heat loss from the system, the condensate flow channel 84 is connected to the ball valve knob 81 of the vacuum layer ball valve 8. When the vacuum layer ball valve 8 is closed, it is not necessary to connect a water inlet to the outlet of the ball valve knob 81; after the crystal pulling process is completed, when the ball valve knob 81 is turned to open the vacuum layer ball valve 8, the water inlet pipe is then connected through the threaded hole provided at the ball valve knob 81.

[0064] In this embodiment, the reflective layer 71 is a metal coating, including a molybdenum coating. In a specific example, the thickness of the molybdenum coating can be 3-7 mm, preferably 5 mm. This thickness range ensures sufficient reflectivity without wasting material.

[0065] The thickness of the first insulation layer 72 is 40-60 mm, preferably 50 mm. In a specific example, the first insulation layer 72 is a soft felt insulation layer, which has better insulation performance.

[0066] The thickness of the second insulation layer 73 is 65-85 mm, preferably 75 mm. In a specific example, the shell of the second insulation layer 73 is made of alumina ceramic, which has excellent high-temperature resistance and mechanical strength.

[0067] The thickness of the support layer 74 is 40-60 mm, preferably 50 mm. In a specific example, the support layer 74 is a rigid felt insulation layer, which provides both good mechanical support and a certain degree of thermal insulation.

[0068] like Figure 1 - Figure 2 As shown, each multi-layer insulation structure 7 is equipped with two vacuum layer ball valves 8, which are connected to the second insulation layer 73 through corresponding vacuum layer valve interfaces 75. The two vacuum layer ball valves 8 are used for the inlet and outlet of the cooling medium, respectively, so that the cooling medium can form a circulating flow in the second insulation layer 73, thereby improving the cooling efficiency.

[0069] The working process of the multi-layer thermal insulation structure 7 provided in this embodiment is as follows:

[0070] I. Installation Preparation Phase

[0071] Vacuuming process:

[0072] Connect the vacuum layer ball valve 8 to the vacuum layer valve interface 75; rotate the ball valve knob 81 to align the condensate flow channel 84 with the vacuum layer valve interface 75; use an external vacuum pump to evacuate the second insulation layer 73; after evacuation, rotate the ball valve knob 81 in the opposite direction to close the valve.

[0073] Hot zone assembly:

[0074] The multi-layer insulation structure 7 is installed in the hot zone of the single crystal furnace, ensuring that each layer is installed in sequence: the reflective layer 71 is attached to the outer surface of the guide tube 1; the first insulation layer 72 covers the outside of the reflective layer 71; the second insulation layer 73 achieves vacuum insulation; and the support layer 74 provides mechanical support.

[0075] II. Production and Operation Phase

[0076] The single crystal furnace is started, and the main heater 4 and the bottom heater 9 heat the quartz crucible 3; the reflective layer 71 reflects the thermal radiation back into the interior of the thermal field; the second insulation layer 73 blocks heat conduction and convection; the vacuum layer ball valve 8 remains closed, and the ball valve sealing layer 83 ensures a vacuum environment.

[0077] III. Cooling End Phase

[0078] Turn on the cooling system: Rotate the ball valve knob 81 to the open position; connect the condensate pipe through the threaded hole; ensure the cooling circulation system is fully connected.

[0079] Cooling process: Condensate is injected through the inlet ball valve; it circulates through the internal space of the second insulation layer 73; and it is discharged from the outlet ball valve, achieving rapid cooling in 3-5 hours.

[0080] Disassembly and maintenance: Close vacuum layer ball valve 8; disconnect condensate water pipe; disassemble after the temperature drops below 200℃.

[0081] The multi-layer insulation structure in this embodiment solves the technical problem that traditional insulation felt cannot achieve both insulation effect and cooling efficiency, thus improving the efficiency and economy of monocrystalline silicon production.

[0082] Example 2

[0083] Please continue to refer to this. Figure 1 This embodiment provides a single-crystal silicon thermal field device, including a flow guide tube 1, a heat insulation tube 2, a quartz crucible 3, a main heater 4, a crucible side 5, a crucible support 6, a multi-layer heat insulation structure 7, a vacuum layer ball valve 8, a bottom heater 9, a support rod 10, and a bottom heat insulation felt 11.

[0084] The top of the single-crystal silicon thermal field device is equipped with a flow guide tube 1 to control the airflow direction and heat field distribution. The flow guide tube 1 is surrounded by an insulation tube 2 to maintain the stability of the thermal field. The central area is the core part for growing single crystals, containing a quartz crucible 3 for holding silicon material. A main heater 4 is arranged around the quartz crucible 3 to melt the silicon material. The side walls of the quartz crucible 3 are supported by crucible sides 5, and the bottom of the quartz crucible 3 is supported by a crucible support 6. This structural design ensures the stability of the quartz crucible 3.

[0085] In a specific example, the flow guide tube 1 is located at the top of the single-crystal silicon thermal field device. Its inner diameter is designed to be between 300 and 500 mm according to the size of the grown single crystal, and its height is between 400 and 600 mm. The material is high-purity graphite, and the surface can be coated with a silicon carbide anti-oxidation coating. The main function of the flow guide tube 1 is to control the airflow direction, maintain the stability of the temperature gradient inside the thermal field, and provide a suitable atmosphere for crystal growth.

[0086] The insulation cylinder 2 is placed around the flow guide cylinder 1, with a certain gap between them. The insulation cylinder 2 is made of high-density graphite felt. The insulation cylinder 2 covers the outer surface of the flow guide cylinder 1, forming the first heat barrier, reducing heat radiation loss and maintaining the stability of the thermal field.

[0087] The quartz crucible 3 is located at the center of the thermal field and is made of high-purity quartz material. Its main function is to hold silicon material and form a liquid silicon molten pool at high temperature.

[0088] The main heater 4 is arranged around the quartz crucible 3, maintaining a certain distance between them. It is made of graphite material and its height is similar to that of the quartz crucible 3. The main heater 4 provides the high-temperature environment required to melt the silicon material by heating it with electricity.

[0089] The crucible sidewall 5 supports the sidewall of the quartz crucible 3, and its height matches the height of the quartz crucible 3. A graphite felt buffer layer is provided between the crucible sidewall 5 and the quartz crucible 3 to reduce the transfer of thermal stress and prevent the quartz crucible 3 from cracking.

[0090] The crucible holder 6 supports the bottom of the quartz crucible 3 and has a diameter 20-30 mm larger than the bottom of the quartz crucible 3. The bottom of the crucible holder 6 has a groove that connects to the top of the support rod 10, enabling lifting and rotation functions.

[0091] A multi-layer insulation structure 7 is installed in the outer area of ​​the thermal field. It adopts the multi-layer insulation structure described in Embodiment 1, including a reflective layer 71, a first insulation layer 72, a second insulation layer 73, and a support layer 74. The height of the multi-layer insulation structure 7 is approximately the same as the height of the main body of the thermal field, and its coverage extends from the bottom of the guide tube 1 to the upper surface of the bottom insulation felt 11.

[0092] The vacuum layer ball valve 8 is installed on the second insulation layer 73 of the multi-layer insulation structure 7, and adopts the structure described in Embodiment 1.

[0093] The bottom heater 9 is located in the bottom region of the single-crystal silicon thermal field device, below the crucible support 6. The bottom heater 9 is powered by an independent power control system and is used to adjust the vertical distribution of the temperature field to ensure the stability of single-crystal growth.

[0094] The support rod 10 supports the entire device, and its length is determined according to the specific dimensions of the single crystal furnace. The top end of the support rod 10 is connected to the crucible holder 6, and the bottom end is connected to the drive system, which enables the lifting and rotating movement of the quartz crucible 3. The support rod 10 has cooling water channels inside.

[0095] A bottom insulation felt 11 is installed in the bottom area, covering the lower surface and surrounding area of ​​the bottom heater 9, and is made of graphite felt material. The diameter of the bottom insulation felt 11 is larger than the diameter of the main body of the thermal field, extending into the inner side of the multi-layer insulation structure 7 to form a complete insulation system and reduce heat loss from the bottom.

[0096] The monocrystalline silicon thermal field device provided in this embodiment, by employing a multi-layer insulation structure 7, particularly the second insulation layer 73 with a vacuum ball valve 8, not only improves the insulation effect of the device but also achieves rapid cooling after furnace shutdown, greatly shortening the production cycle and improving equipment utilization. Through the organic combination and synergistic work of various components, high-efficiency and high-quality monocrystalline silicon production is achieved, with good economic efficiency and reliability.

[0097] In summary, this utility model provides a multi-layer insulation structure and a single-crystal silicon thermal field device. The multi-layer insulation structure, through the synergistic effect of the reflective layer, the first insulation layer, the second insulation layer, and the support layer, improves the insulation effect, reduces the power consumption of the heater, and saves production costs. The design of the vacuum layer ball valve ensures both vacuum insulation and allows for rapid introduction of cooling medium when needed, significantly shortening cooling time and improving production efficiency. The ball valve structure achieves vacuum system sealing while being easy to operate and maintain. The rapid cooling function also reduces the oxidation loss of carbon fibers inside the multi-layer insulation structure, extending its service life.

[0098] The monocrystalline silicon thermal field device provided by this utility model organically integrates a multi-layer insulation structure into the overall thermal field system, forming a highly efficient, energy-saving, and stable monocrystalline silicon growth environment. When the thermal field system is working, the multi-layer insulation structure provides a stable thermal field environment for the entire device, reducing heat loss and energy consumption; when furnace shutdown for cooling is required, the integrated vacuum layer ball valve system can quickly start the cooling process, significantly shortening equipment downtime and improving overall production efficiency.

[0099] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A multi-layer thermal insulation structure, characterized in that, It includes, from the inside out, a reflective layer, a first insulation layer, a second insulation layer, and a support layer; The second insulation layer is provided with a vacuum device that communicates with its interior. The vacuum device includes a vacuum layer valve interface and a vacuum layer ball valve. The vacuum layer ball valve is connected to the second insulation layer through the vacuum layer valve interface.

2. The multi-layer thermal insulation structure according to claim 1, characterized in that, The vacuum layer ball valve includes: Ball valve housing; The internal rotating shaft of the ball valve is located inside the ball valve housing; The ball valve knob is connected to the internal rotating shaft of the ball valve; and the ball valve inlet and outlet provided on the ball valve housing; The ball valve has a condensate flow channel on its internal rotating shaft, and one end of the condensate flow channel is connected to the inlet and outlet of the ball valve.

3. The multi-layer thermal insulation structure according to claim 2, characterized in that, The ball valve knob is provided with a threaded hole for connecting an external pipe.

4. The multi-layer thermal insulation structure according to claim 2, characterized in that, A ball valve sealing layer is provided at the joint between the ball valve housing and the internal rotating shaft of the ball valve.

5. The multi-layer thermal insulation structure according to claim 2, characterized in that, Rotating the ball valve knob aligns or offsets the condensate flow channel with the vacuum layer valve interface, thus opening or closing the vacuum layer ball valve.

6. The multi-layer thermal insulation structure according to claim 1, characterized in that, The reflective layer is a metal coating, which includes a molybdenum coating with a thickness of 3-7 mm.

7. The multi-layer thermal insulation structure according to claim 1, characterized in that, The thickness of the first insulation layer is 40-60mm; the thickness of the second insulation layer is 65-85mm; and the thickness of the support layer is 40-60mm.

8. The multi-layer thermal insulation structure according to claim 1, characterized in that, The vacuum layer ball valve is provided in two parts, one of which is connected to the feed pipe and the other is connected to the discharge pipe.

9. A single-crystal silicon thermal field device, characterized in that, include: Flow deflector; A heat-insulating cylinder is disposed around the flow guide cylinder; Quartz crucibles are used to hold silicon materials; The main heater is positioned around the quartz crucible; The crucible sidewalls support the side walls of the quartz crucible; A crucible support, used to support the bottom of the quartz crucible; A multi-layer insulation structure is installed in the outer area of ​​the thermal field; A bottom heater is disposed in the bottom region of the single-crystal silicon thermal field device; Support rods are used to support the entire device; as well as Bottom insulation felt is installed in the bottom area; The multi-layer insulation structure is the multi-layer insulation structure described in any one of claims 1-8.

Images