Thermal field insulation structure and single crystal furnace

Abstract

The utility model discloses a thermal field thermal insulation structure and a single crystal furnace, the thermal field thermal insulation structure comprises at least one thermal insulation cylinder, and each thermal insulation cylinder comprises an outer cylinder body; the inner barrel is coaxial with the outer barrel, and the inner barrel is located in the outer barrel; the outer cylinder body is connected with the inner cylinder body through the connecting piece, and the outer cylinder body, the connecting piece and the inner cylinder body define a containing cavity; the containing cavity is filled with the heat preservation felt. In the embodiment of the utility model, the box body structure consisting of the outer cylinder body, the connecting piece and the inner cylinder body can protect the heat-insulating felt in the box body structure, slow down the pulverization of the soft felt layer in the heat-insulating felt, prolong the service life of the heat-insulating felt and reduce the replacement frequency of the heat-insulating felt.

Description

Technical Field

[0001] The utility model relates to the technical field of single crystal production, in particular to a thermal field insulation structure and a single crystal furnace. Background Art

[0002] The thermal system of a single crystal furnace is also called a thermal field, which includes a heat preservation tube. At present, the heat preservation tube includes a tube body and a soft felt rolled outside the tube. After the soft felt is rolled, it is also necessary to use molybdenum wire or cable ties to bind the soft felt.

[0003] However, after the soft felt is powdered, the furnace needs to be stopped and the soft felt needs to be replaced manually. Since the soft felt rolled outside the cylinder is directly exposed, it powders quickly, which leads to frequent replacement of the soft felt and a long total replacement time, affecting the normal production of the single crystal furnace. Utility Model Content

[0004] The utility model provides a thermal field insulation structure and a single crystal furnace, aiming to at least solve the technical problems in the prior art that the felt on the first insulation cylinder is frequently replaced, the total replacement time is long, and the normal production of the single crystal furnace is affected.

[0005] In a first aspect, an embodiment of the utility model provides a thermal field insulation structure, comprising at least one insulation cylinder, each of which comprises:

[0006] outer cylinder;

[0007] An inner cylinder, coaxial with the outer cylinder, and the inner cylinder is located inside the outer cylinder;

[0008] A connecting piece, the outer cylinder is connected to the inner cylinder through the connecting piece, and the outer cylinder, the connecting piece and the inner cylinder form a containing cavity;

[0009] The thermal insulation felt is filled in the accommodating cavity.

[0010] Optionally, the thermal insulation felt includes a solid felt layer and / or a soft felt layer.

[0011] Optionally, a soft felt layer is provided on a side of the solid felt layer close to the outer cylinder, and / or a soft felt layer is provided on a side of the solid felt layer close to the inner cylinder, and / or a coating is provided on the outer surface of the solid felt layer.

[0012] Optionally, the thickness of the soft felt layer is smaller than the thickness of the solid felt layer.

[0013] Optionally, a groove is provided on the outer wall of the outer cylinder, and the groove is arranged along the circumference of the outer cylinder.

[0014] Optionally, at least one of the heat-insulating cylinders includes a first heat-insulating cylinder and a second heat-insulating cylinder, the first heat-insulating cylinder also includes a first cover plate covering the top of the accommodating cavity, and the second heat-insulating cylinder is placed on the first cover plate.

[0015] Optionally, the inner diameter of the second thermal insulation cylinder is smaller than the inner diameter of the first thermal insulation cylinder; and / or, the first thermal insulation cylinder is composed of at least two first sub-thermal insulation cylinders, at least two of which are stacked to form the first thermal insulation cylinder; and / or, the second thermal insulation cylinder is composed of at least two second sub-thermal insulation cylinders, at least two of which are stacked to form the second thermal insulation cylinder; and / or, the second thermal insulation cylinder also includes a second cover plate disposed on the top of the accommodating cavity.

[0016] Optionally, the outer cylinder, the inner cylinder and the connecting piece are separate structures or integrated structures.

[0017] Optionally, the outer cylinder, the inner cylinder and the connecting piece are connected by tenon connection, threaded connection, welding, riveting or stopper connection.

[0018] Optionally, the first sub-insulation tube and / or the second sub-insulation tube are connected by a stopper; and / or a connecting piece is provided between the first sub-insulation tube and / or the second sub-insulation tube, and the connecting piece includes a main body plate portion, and the main body plate portion is connected to the first sub-insulation tube and / or the second insulation tube by a stopper; and / or the connecting piece includes a main body plate portion, and the outer cylinder body and / or the inner cylinder body are connected to the main body plate portion by a stopper; or, the connecting piece is located between the outer cylinder body and the inner cylinder body.

[0019] In a second aspect, an embodiment of the utility model provides a single crystal furnace, comprising the thermal field insulation structure described in any one of the above items.

[0020] In the embodiment of the utility model, the box structure composed of the outer cylinder, the connecting piece and the inner cylinder can protect the insulation felt therein and slow down the pulverization of the insulation felt, thereby reducing the replacement frequency of the insulation felt and shortening the total replacement time of the insulation felt, thus avoiding the impact on the normal production of the single crystal furnace caused by the frequent replacement of the felt on the insulation cylinder and the total replacement time. In addition, the insulation cylinder adopts a coaxially arranged double-cylinder structure, which reduces heat loss and improves the insulation performance compared to the single-cylinder structure. In addition, the box structure composed of the outer cylinder, the connecting piece and the inner cylinder can also prevent the insulation felt from falling off, thereby avoiding the risk of high carbon or ignition caused by the insulation felt falling off.

[0021] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1A schematic cross-sectional view of a thermal field insulation structure provided by an embodiment of the utility model;

[0023] Figure 2 A schematic diagram of the three-dimensional structure of the thermal field insulation structure provided by an embodiment of the utility model;

[0024] Figure 3 A schematic diagram of the structure of a second cover plate provided in an embodiment of the utility model;

[0025] Figure 4 A schematic diagram of the three-dimensional structure of a first sub-insulation cylinder provided in an embodiment of the utility model;

[0026] Figure 5 A schematic cross-sectional view of a first sub-insulation cylinder provided in an embodiment of the utility model;

[0027] Figure 6 A schematic diagram of the three-dimensional structure of another first sub-insulation cylinder provided in an embodiment of the utility model;

[0028] Figure 7 A schematic cross-sectional view of another first sub-insulation cylinder provided in an embodiment of the utility model;

[0029] Figure 8 A schematic diagram of the three-dimensional structure of another first sub-insulation cylinder provided in an embodiment of the utility model.

[0030] Reference numerals:

[0031] 1-outer cylinder, 11-groove, 2-inner cylinder, 3-connecting piece, 31-main plate, 32-first convex stop, 4-thermal insulation felt, 41-solid felt layer, 42-soft felt layer, 5-connecting bolts, 6-second thermal insulation cylinder, 61-second cover plate, 611-fourth convex stop, 7-first thermal insulation cylinder, 71-first cover plate, 72-first sub-thermal insulation cylinder. DETAILED DESCRIPTION

[0032] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0033] First, refer to Figure 1 and Figure 2The utility model embodiment discloses a thermal field insulation structure, including at least one insulation cylinder, each insulation cylinder includes: an outer cylinder 1; an inner cylinder 2, which is coaxial with the outer cylinder 1 and located inside the outer cylinder 1; a connecting piece 3, the outer cylinder 1 is connected to the inner cylinder 2 through the connecting piece 3, and the outer cylinder 1, the connecting piece 3 and the inner cylinder 2 form a containing cavity; and an insulation felt 4 is filled in the containing cavity.

[0034] In an practicable manner, the thermal field insulation structure preferably includes an insulation cylinder, and three insulation cylinders are coaxially arranged from top to bottom. The outer cylinder 1 and the inner cylinder 2 are both annular structures, and the material of the outer cylinder 1 is the same as that of the inner cylinder 2, and both can be carbon-carbon composite materials. The insulation cylinder adopts a coaxially arranged double-cylinder structure, which reduces heat loss and improves insulation performance compared to a single-cylinder structure.

[0035] The box structure composed of the outer cylinder 1, the connector 3 and the inner cylinder 2 can protect the insulation felt 4 therein, slow down the pulverization of the soft felt layer 42 in the insulation felt 4, thereby reducing the replacement frequency of the insulation felt 4 and shortening the total replacement time of the insulation felt 4. In addition, the box structure composed of the outer cylinder 1, the connector 3 and the inner cylinder 2 can also prevent the solid felt from falling off, thereby avoiding the risk of carbon high or ignition caused by the solid felt falling off.

[0036] In one practicable manner, the thermal insulation felt 4 includes a solid felt layer 41 and / or a soft felt layer 42 .

[0037] In an operative manner, the thermal insulation felt 4 may include only a solid felt layer 41 or only a soft felt layer 42. The thermal insulation felt 4 preferably includes both a solid felt layer 41 and a soft felt layer 42. The solid felt layer 41 includes solid felt, and the material of the solid felt may be PAN-based felt, viscose-based felt, etc. The soft felt layer 42 includes soft felt, and the strength of the soft felt is lower than that of the solid felt.

[0038] In the prior art, it takes a long time to roll the soft felt; it is difficult to tie the soft felt tightly with molybdenum wire or cable tie, and it is easy to collapse; and after the heat field increases, the soft felt is easy to rub against the furnace body, causing the felt to loosen and fluff. In the embodiment of the utility model, the insulation felt 4 is directly placed in the accommodating cavity, without the need to roll and tie the felt, further shortening the replacement time of the insulation felt 4; and the outermost layer is the outer cylinder 1, which prevents the friction between the soft felt and the furnace body.

[0039] The service life of soft felt is shorter than that of solid felt, and the cost of soft felt is higher than that of solid felt. If the accommodating cavity is filled with only soft felt, the service life of the thermal insulation felt 4 will be short, the replacement will be frequent, and the cost will be high. The heat conduction of solid felt is faster. If the accommodating cavity is filled with only solid felt, the thermal insulation performance of the thermal insulation felt 4 will be relatively poor. In the embodiment of the utility model, the thermal insulation felt 4 adopts a combination of soft felt and solid felt, which ensures the thermal insulation performance, improves the service life of the thermal insulation felt 4, reduces the replacement frequency of the thermal insulation felt 4, and thus shortens the total replacement time of the thermal insulation felt 4, avoiding the impact on the normal production of the single crystal furnace caused by frequent replacement of the felt on the insulation tube and the long total replacement time. In addition, the thermal insulation felt 4 adopts a combination of soft felt and solid felt, which reduces the use of soft felt and reduces the cost.

[0040] In one practicable manner, a soft felt layer 42 is provided on the side of the solid felt layer 41 close to the outer cylinder 1, and / or a soft felt layer 42 is provided on the side of the solid felt layer 41 close to the inner cylinder 2, and / or a coating is provided on the outer surface of the solid felt layer 41.

[0041] Preferably, a soft felt layer 42 is provided on the side of the solid felt layer 41 close to the outer cylinder 1, and a soft felt layer 42 is also provided on the side of the solid felt layer 41 close to the inner cylinder 2, that is, the thermal insulation felt 4 includes a three-layer felt structure of a soft felt layer 42, a solid felt layer 41 and a soft felt layer 42. Both the soft felt layer 42 and the solid felt layer 41 are annular structures. By providing the soft felt layer 42, the friction between the solid felt layer 41 and the outer cylinder 1 and / or the inner cylinder 2 can be reduced, thereby reducing the wear of the solid felt layer 41, and the thermal insulation felt 4 is easy to put in and take out when replaced.

[0042] In one practicable manner, the thickness of the soft felt layer 42 is smaller than the thickness of the solid felt layer 41 .

[0043] In a specific embodiment, referring to Figure 1 , the sum of the thicknesses of the two soft felt layers 42 is less than the thickness of the solid felt layer 41. The thickness of the soft felt layer 42 is preferably less than or equal to 1 / 5 of the thickness of the solid felt layer 41. The thickness of the soft felt layer 42 may be 1 mm to 10 mm. The cost of soft felt is high and the service life is short. By setting the thickness of the soft felt layer 42 to be less than the thickness of the solid felt layer 41, the service life of the thermal insulation felt 4 is increased and the cost is reduced.

[0044] In one practicable manner, referring to Figure 1 and Figure 2 A groove 11 is provided on the outer wall of the outer cylinder 1 , and the groove 11 is arranged along the circumference of the outer cylinder 1 .

[0045] In a specific embodiment, the groove 11 is preferably located in the middle of the outer cylinder 1. The groove 11 is used to cooperate with the disassembly and assembly strap. The cross-sectional shape of the groove 11 may be rectangular, and the size of the groove 11 is determined according to the size of the disassembly and assembly strap. The width of the groove 11 may be greater than or equal to the width of the disassembly and assembly strap, and the depth of the groove 11 may be greater than or equal to the thickness of the disassembly and assembly strap. When removing the thermal insulation cylinder, first wrap the disassembly and assembly strap in the groove 11, and then lift the thermal insulation cylinder by pulling the disassembly and assembly strap. When installing the thermal insulation cylinder, lift the thermal insulation cylinder to the installation position by the disassembly and assembly strap, and then remove the disassembly and assembly strap.

[0046] In the embodiment of the utility model, the disassembly and assembly of the insulation cylinder can be achieved through the cooperation of the groove 11 and the disassembly and assembly strap, without the need to set up a filter plate, and it is convenient for manual disassembly and assembly; in addition, when the insulation cylinder is disassembled and lifted, the disassembly and assembly strap is embedded in the groove 11 of the outer cylinder body 1, thereby preventing the insulation cylinder from slipping during the lifting process and ensuring safety.

[0047] In one practicable manner, referring to Figure 2 and Figure 3 At least one heat-insulating tube includes a second heat-insulating tube 6 and a first heat-insulating tube 7 , the first heat-insulating tube 7 also includes a first cover plate 71 covering the top of the accommodating cavity, and the second heat-insulating tube 6 is placed on the first cover plate 71 .

[0048] The second heat-insulating tube 6 and the first heat-insulating tube 7 are coaxially arranged from top to bottom. The inner diameter of the second heat-insulating tube 6 is different from the inner diameter of the first heat-insulating tube 7. The first heat-insulating tube 7 can be formed by stacking at least two first sub-heat-insulating tubes 72. The second heat-insulating tube 6 can be only one, or can be formed by stacking at least two second sub-heat-insulating tubes.

[0049] The material of the first cover plate 71 can be the same as that of the outer cylinder 1, for example, a carbon-carbon composite material. The first cover plate 71 is an annular structure. The first cover plate 71 can be directly placed on the outer cylinder 1 and the inner cylinder 2 at the top of the first thermal insulation cylinder 7, or can be connected to the outer cylinder 1 and the inner cylinder 2 at the top by means of a tenon connection, a threaded connection, welding, a riveting or a stopper. On the one hand, the first cover plate 71 can ensure the airtightness of the accommodating cavity in the first thermal insulation cylinder 7, and on the other hand, it also plays a role in supporting the second thermal insulation cylinder 6.

[0050] In one embodied manner, the inner diameter of the second thermal insulation tube 6 is smaller than the inner diameter of the first thermal insulation tube 7; and / or, the first thermal insulation tube 7 is composed of at least two first sub-thermal insulation tubes 72, which are stacked to form the first thermal insulation tube 7; and / or, the second thermal insulation tube 6 is composed of at least two second sub-thermal insulation tubes, which are stacked to form the second thermal insulation tube 6; and / or, the second thermal insulation tube 6 also includes a second cover plate 61 disposed on the top of the accommodating cavity.

[0051] Specifically, the material of the second cover plate 61 can be the same as that of the outer cylinder 1, for example, a carbon-carbon composite material. The second cover plate 61 is an annular structure. The second cover plate 61 can be directly placed on the outer cylinder 1 and the inner cylinder 2 in the second thermal insulation cylinder 6, or it can be connected to the outer cylinder 1 and the inner cylinder 2 by a tenon connection, a threaded connection, welding, a riveting or a stopper. The provision of the second cover plate 61 can ensure the airtightness of the accommodating cavity in the second thermal insulation cylinder 6. The first thermal insulation cylinder 7 is preferably formed by stacking two first sub-thermal insulation cylinders 72.

[0052] In an practicable manner, the first cover plate 71 is connected to the first heat-insulating tube 7 by means of a stopper, and the second cover plate 61 is connected to the second heat-insulating tube 6 by means of a stopper.

[0053] In a specific embodiment, at least one third convex stop is provided on the first cover plate 71, and a third concave stop matched with the third convex stop is also provided on the first heat-insulating tube 7; at least one fourth convex stop 611 is provided on the second cover plate 61, and a fourth concave stop matched with the fourth convex stop 611 is also provided on the second heat-insulating tube 6. The third convex stop and the fourth convex stop 611 are both facing downward. A third convex stop is provided on the first cover plate 71, and a third concave stop for matching with the third convex stop is provided on the outer wall of the outer cylinder 1 in the top first sub-heat-insulating tube 72. A fourth convex stop 611 is provided on the second cover plate 61, and a fourth concave stop for matching with the fourth convex stop 611 is provided on the outer wall of the outer cylinder 1 in the second heat-insulating tube 6.

[0054] In an practicable manner, the outer cylinder 1, the inner cylinder 2 and the connecting member 3 are separate structures or an integral structure.

[0055] Reference Figure 8 When the outer cylinder 1, the inner cylinder 2 and the connecting piece 3 are an integral structure, the outer cylinder 1, the inner cylinder 2 and the connecting piece 3 are integrally formed and do not need to be assembled.

[0056] When the outer cylinder 1, the inner cylinder 2 and the connecting piece 3 are of separate structures, the connection between the connecting piece 3 and the outer cylinder 1 and the inner cylinder 2 can be a tenon connection, a threaded connection, welding, a riveting connection or a stopper connection, etc. When the outer cylinder 1, the inner cylinder 2 and the connecting piece 3 are of separate structures, compared with an integrated structure, the processing cost is reduced, and a single component can be replaced separately after being damaged, thereby reducing the maintenance cost.

[0057] In an operative manner, the connector 3 comprises a main body plate portion 31 , and the main body plate portion 31 is connected to the outer cylinder 1 and / or the inner cylinder 2 by using a stopper.

[0058] In a specific embodiment, referring to Figure 4 and Figure 5The connector 3 includes a main body plate portion 31 and at least one first convex stop 32 connected to the main body plate portion 31, and a first concave stop matched with the first convex stop 32 is provided on the outer cylinder 1 and / or the inner cylinder 2. The first concave stop and the first convex stop 32 can improve the assembly accuracy of the connector 3 and avoid misalignment during assembly.

[0059] The connected parts of two adjacent first sub-insulation tubes 72 and / or second sub-insulation tubes can be connected in a detachable manner, and the detachable connection methods include tenon connection, threaded connection, welding, riveting or stop connection, preferably stop connection.

[0060] In an operative manner, a stopper is provided on the outer cylinder 1 and / or the inner cylinder 2 of the first sub-insulation cylinder 72. A convex stopper is provided on the outer cylinder 1 and / or the inner cylinder 2 of one of the first sub-insulation cylinders 72, and a concave stopper is provided on the outer cylinder 1 and / or the inner cylinder 2 of the other first sub-insulation cylinder 72.

[0061] In one practicable manner, a connector 3 is provided between the first sub-insulation tube 72 and / or the second sub-insulation tube. The connector 3 includes a main body plate 31. The main body plate 31 is connected to the first sub-insulation tube 72 and / or the second insulation tube by a stopper.

[0062] The main body plate 31 between the two first sub-insulation tubes 72 and / or the second sub-insulation tube is provided with two stoppers with different directions. The stoppers facing upward and downward on the main body plate 31 are both convex stoppers or concave stoppers, and the first sub-insulation tube 72 and / or the second sub-insulation tube are provided with corresponding stoppers.

[0063] In a specific embodiment, two convex stoppers are provided on the main body plate portion 31 between the two first sub-insulation tubes 72, and the two convex stoppers are oriented in different directions. The first sub-insulation tube 72 is provided with a concave stopper matched with the convex stopper, and the concave stopper is arranged along the circumference of the first sub-insulation tube 72. When at least two first sub-insulation tubes 72 are placed, a single first sub-insulation tube 72 can be placed in sequence. By setting the convex stopper and the concave stopper in this embodiment, it can be ensured that the first sub-insulation tube 72 placed later is coaxial with the first sub-insulation tube 72 placed earlier, so as to avoid misalignment when placing.

[0064] Except for the topmost first sub-insulation tube 72 , the remaining first sub-insulation tubes 72 are not provided with cover plates, and the middle connecting member 3 is used as the cover plate of the remaining first sub-insulation tubes 72 to reduce material cost.

[0065] In one practicable manner, referring to Figure 6 and Figure 7 , the connecting member 3 is located between the outer cylinder 1 and the inner cylinder 2. In this embodiment, the connecting member 3 is an annular plate structure, and the connecting structure is simple.

[0066] Reference Figures 4 to 7 When the outer cylinder 1, the inner cylinder 2 and the connecting member 3 are separate structures, the connecting member 3 can be detachably connected to the bottom of the outer cylinder 1 and the inner cylinder 2.

[0067] Specifically, the connector 3 is connected to the outer cylinder 1 and the inner cylinder 2 through a plurality of connecting bolts 5, and the connecting bolts 5 penetrate the connector 3, the outer cylinder 1 and the inner cylinder 2. The plurality of connecting bolts 5 are evenly distributed along the circumference of the outer cylinder 1. When the connector 3 is detachably connected to the bottom of the outer cylinder 1 and the inner cylinder 2, a single component can be quickly removed without destroying the connection, which is conducive to the repair and replacement of a single component.

[0068] The outer cylinder 1 and the inner cylinder 2 are both made of carbon-carbon composite materials, and the connector 3 is made of carbon-carbon composite materials. Carbon-carbon composite materials have a low thermal conductivity, can reduce heat loss, and have a good thermal insulation effect.

[0069] In a second aspect, the embodiment of the utility model further discloses a single crystal furnace, comprising any one of the above-mentioned thermal field insulation structures. The single crystal furnace comprises a furnace body, and the thermal field insulation structure is arranged in the furnace body. Since the single crystal furnace comprises the above-mentioned thermal field insulation structure, it also has the beneficial effects of the above-mentioned thermal field insulation structure, which will not be described in detail here.

[0070] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0071] The embodiments of the utility model are described above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the utility model, ordinary technicians in this field can also make many forms without departing from the scope of protection of the utility model and the claims, which all fall within the protection of the utility model.

Claims

1. A thermal field insulation structure, characterized in that: It includes at least one heat preservation tube, each of which includes: outer cylinder; An inner cylinder, coaxial with the outer cylinder, and the inner cylinder is located inside the outer cylinder; A connecting piece, the outer cylinder is connected to the inner cylinder through the connecting piece, and the outer cylinder, the connecting piece and the inner cylinder form a containing cavity; The thermal insulation felt is filled in the accommodating cavity.

2. The thermal field insulation structure according to claim 1, characterized in that: The thermal insulation felt comprises a solid felt layer and / or a soft felt layer.

3. The thermal field insulation structure according to claim 2, characterized in that: A soft felt layer is provided on one side of the solid felt layer close to the outer cylinder, and / or a soft felt layer is provided on one side of the solid felt layer close to the inner cylinder, and / or a coating is provided on the outer surface of the solid felt layer.

4. The thermal field insulation structure according to claim 3, characterized in that: The thickness of the soft felt layer is smaller than the thickness of the solid felt layer.

5. The thermal field insulation structure according to claim 1, characterized in that: A groove is formed on the outer wall of the outer cylinder, and the groove is arranged along the circumference of the outer cylinder.

6. The thermal field insulation structure according to claim 1, characterized in that: At least one of the heat-insulating cylinders includes a first heat-insulating cylinder and a second heat-insulating cylinder, wherein the first heat-insulating cylinder also includes a first cover plate covering the top of the accommodating cavity, and the second heat-insulating cylinder is placed on the first cover plate.

7. The thermal field insulation structure according to claim 6, characterized in that: The inner diameter of the second thermal insulation tube is smaller than the inner diameter of the first thermal insulation tube; and / or, the first thermal insulation tube is composed of at least two first sub-thermal insulation tubes, and at least two of the first sub-thermal insulation tubes are stacked to form the first thermal insulation tube; and / or, the second thermal insulation tube is composed of at least two second sub-thermal insulation tubes, and at least two of the second sub-thermal insulation tubes are stacked to form the second thermal insulation tube; and / or, the second thermal insulation tube also includes a second cover plate covered on the top of the accommodating cavity.

8. The thermal field insulation structure according to claim 1, characterized in that: The outer cylinder, the inner cylinder and the connecting piece are of separate structures or integrated structures.

9. The thermal field insulation structure according to claim 8, characterized in that: The outer cylinder, the inner cylinder and the connecting piece are connected by tenon connection, thread connection, welding, riveting or stopper connection.

10. The thermal field insulation structure according to claim 7, characterized in that: The first sub-insulation tube and / or the second sub-insulation tube are connected by a stopper; and / or a connecting piece is provided between the first sub-insulation tube and / or the second sub-insulation tube, and the connecting piece includes a main body plate, and the main body plate is connected to the first sub-insulation tube and / or the second insulation tube by a stopper; and / or the connecting piece includes a main body plate, and the outer cylinder body and / or the inner cylinder body are connected to the main body plate by a stopper; or, the connecting piece is located between the outer cylinder body and the inner cylinder body.

11. A single crystal furnace, characterized in that: It comprises the thermal field insulation structure according to any one of claims 1 to 10.

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