Low-power-consumption thermal insulation cylinder for thermal field of Czochralski single crystal furnace

Abstract

The utility model relates to a low-power-consumption thermal insulation cylinder for a thermal field of a Czochralski single crystal furnace, which belongs to the technical field of single crystal furnaces and comprises an upper-layer thermal insulation cylinder and a lower-layer thermal insulation cylinder, the lower-layer thermal insulation cylinder consists of a middle thermal insulation cylinder and a lower thermal insulation cylinder which are integrally formed, the lower thermal insulation cylinder is a double-layer thermal insulation cylinder, and a lower-layer thermal insulation felt is wrapped outside the lower-layer thermal insulation cylinder. The lower heat preservation cylinder is of a double-layer structure, an inner-layer heat preservation cylinder is arranged in the lower heat preservation cylinder, a space is reserved between the lower heat preservation cylinder and the inner-layer heat preservation cylinder to be filled with heat preservation materials, two grooves are formed in the inner-layer heat preservation cylinder, and the edge of the inner-layer heat preservation cylinder extends towards the inner wall of the lower heat preservation cylinder to enable the space between the inner-layer heat preservation cylinder and the lower heat preservation cylinder to be a sealed space. A furnace bottom heat preservation layer is arranged at the bottom end of the lower-layer heat preservation cylinder, the upper surface of the furnace bottom heat preservation layer protrudes upwards to form a step, the lower-layer heat preservation cylinder is nested on the furnace bottom heat preservation layer through the step, and the protruding part in the furnace bottom heat preservation layer is located in the lower-layer heat preservation cylinder. The thermal insulation cylinder effectively reduces heat loss and reduces production power consumption of the single crystal furnace.

Description

Technical Field

[0001] The utility model relates to a heat preservation cylinder, in particular to a heat preservation cylinder for the thermal field of a low-power Czochralski single crystal furnace, belonging to the technical field of single crystal furnaces. Background Technique

[0002] In the production process of single crystal rods, in addition to the cost of original auxiliary materials, power consumption is also a major part of production costs, and electricity prices have also become one of the influencing factors for the location selection of single crystal silicon factories. Optimizing the existing thermal field or developing a new thermal field to reduce production power consumption has also become a key research area in single crystal silicon production.

[0003] The existing heat preservation cylinders for single crystal furnaces are generally made of C / C composite materials, in a straight cylinder shape, wrapped with heat preservation materials, and are divided into upper, middle and lower parts. The lower heat preservation cylinder is located above the layered stacked furnace bottom heat preservation, the middle heat preservation cylinder is located above the lower heat preservation cylinder, and the upper heat preservation cylinder is located above the middle heat preservation cylinder, and the installation is completed by splicing in sequence. This structure has the following problems:

[0004] First, the thermal conductivity of C / C composite materials is relatively high; second, there is a certain space below the heating area of the main heater, and the space utilization rate is insufficient; third, when the heat preservation cylinders are directly spliced and installed, there will be gaps, causing heat to be lost from the splicing seams of the heat preservation cylinders and reducing the heat preservation performance; fourth, the layered stacked furnace bottom heat preservation will cause the heat emitted by the heater electrodes to be conducted outward through the gaps between the furnace bottom heat preservation felts, resulting in heat loss.

[0005] Patent CN212771048U, a double-layer thermal field heat preservation cylinder for a single crystal furnace, through the setting that the cylinder body is composed of a double-layer structure of an outer heat preservation wall and an inner heat preservation wall, thus facilitating the improvement of the heat preservation effect of the heat preservation cylinder itself. At the same time, through the mutual cooperation between the heat preservation body and the first heat preservation protrusion and the second heat preservation protrusion, the heat isolation effect of the cylinder body itself is improved, and the heat preservation effect of the heat preservation cylinder itself is improved. However, for this heat preservation cylinder, only the heat preservation effect is improved in the vertical direction of the heat preservation cylinder, and there is still heat loss at the furnace bottom heat preservation, and the heat preservation effect needs to be improved.

[0006] Therefore, developing a heat preservation cylinder for the thermal field of a low-power Czochralski single crystal furnace that can overcome the above defects has become an urgent technical problem for those skilled in the art. Content of the Utility Model

[0007] The technical problem to be solved by the utility model is to overcome the shortcomings of the prior art and provide a heat preservation cylinder for the thermal field of a low-power Czochralski single crystal furnace, which can effectively reduce heat loss and reduce the production power consumption of the single crystal furnace.

[0008] To solve the above technical problems, the present utility model provides a heat preservation cylinder for the heat field of a low-power Czochralski single crystal furnace, which includes an upper heat preservation cylinder and a lower heat preservation cylinder. The lower heat preservation cylinder is arranged at the lower end of the upper heat preservation cylinder. The lower heat preservation cylinder is composed of a middle heat preservation cylinder and a lower heat preservation cylinder which are integrally formed. The lower heat preservation cylinder is located at the lower end of the middle heat preservation cylinder. The lower heat preservation cylinder is a double-layer heat preservation cylinder, and a lower heat preservation felt is wrapped outside the lower heat preservation cylinder. Among them:

[0009] The lower heat preservation cylinder is of a double-layer structure, and an inner heat preservation cylinder is arranged inside the lower heat preservation cylinder to form a double-layer heat preservation cylinder. A space is left between the lower heat preservation cylinder and the inner heat preservation cylinder to be filled with heat preservation materials. Grooves are respectively arranged at the positions of two corresponding main heater legs on the inner heat preservation cylinder. The edge of the inner heat preservation cylinder extends downward to the inner wall of the lower heat preservation cylinder, so that the space between the inner heat preservation cylinder and the lower heat preservation cylinder is a sealed space;

[0010] A furnace bottom heat preservation layer is arranged at the bottom end of the lower heat preservation cylinder. The upper surface of the furnace bottom heat preservation layer protrudes upward to form a step. The lower heat preservation cylinder is nested on the furnace bottom heat preservation layer through the step, and the protruding part in the furnace bottom heat preservation layer is located inside the lower heat preservation cylinder.

[0011] A further limited technical solution of the present utility model is:

[0012] Further, in the above-mentioned heat preservation cylinder for the heat field of a low-power Czochralski single crystal furnace, the heat preservation materials in the lower heat preservation cylinder and the inner heat preservation cylinder are graphite felts.

[0013] In the above-mentioned heat preservation cylinder for the heat field of a low-power Czochralski single crystal furnace, the width of the lower heat preservation felt is equal to the height of the lower heat preservation cylinder.

[0014] Technical effect: The present utility model uses a heat preservation felt with a width equal to the total height of the two heat preservation cylinders for wrapping, so that the original two heat preservation cylinder felts are integrated, avoiding heat loss caused by the splicing seam of the two heat preservation cylinder felts, strengthening the heat preservation ability in the middle and reducing power consumption.

[0015] In the above-mentioned heat preservation cylinder for the heat field of a low-power Czochralski single crystal furnace, the materials of the upper heat preservation cylinder and the lower heat preservation cylinder are both made of C / SiC.

[0016] Technical effect: Generally, C / C composite materials are used at present. The thermal conductivity of C / C composite materials is relatively high. The present invention uses C / SiC as the material of the heat preservation cylinder, hereinafter referred to as a carbon-ceramic material heat preservation cylinder. The thermal conductivity of the carbon-ceramic material is 40-60 (w / m•k), which is lower than that of carbon-carbon composite materials and graphite materials, effectively reducing heat loss.

[0017] In the above-mentioned heat preservation cylinder for the heat field of a low-power Czochralski single crystal furnace, the inner heat preservation cylinder is located at the upper end inside the lower heat preservation cylinder.

[0018] In the aforementioned heat preservation cylinder for the direct-pull single crystal furnace with low power consumption, the upper end of the inner heat preservation cylinder is flush with the upper end of the lower heat preservation cylinder, and the lower end of the inner heat preservation cylinder is not less than 100 mm away from the upper surface of the furnace bottom heat preservation layer.

[0019] Technical effect: The upper end of the inner heat preservation cylinder is located inside the lower heat preservation cylinder. It can be seen from Figure 1 that there is actually a bottom heater between the furnace bottom heat preservation layer and the crucible side. Setting it at the upper end can prevent the inner heat preservation cylinder from being too close to the bottom heater, causing the bottom heater to arc (that is, the heater is short-circuited. Since the heat field of the single crystal furnace is basically made of graphite and carbon-carbon materials, which are excellent conductors, and the power supply used in the single crystal furnace is 380V, with a maximum current of more than 2000A, if the heater is too close to the heat preservation material, arc striking will occur, which will affect production at least and cause major safety accidents at worst).

[0020] The beneficial effects of the present utility model are:

[0021] In the industry, the lower heat preservation cylinder is usually a single-layer cylinder. Due to the limitation of the inner diameter of the single crystal furnace wall, the number of layers of the felt of the lower heat preservation cylinder cannot be increased infinitely. The present utility model adds an inner heat preservation cylinder inside the lower heat preservation cylinder to form a double-layer structure. There is a gap space between the two heat preservation cylinders, and heat preservation materials are filled in the middle. Both the upper and lower parts of the two heat preservation cylinders are sealed to prevent the heat preservation materials from being exposed. There are two grooves on the inner heat preservation cylinder to avoid interference with the legs of the main heater. The present utility model utilizes the space below the main heater to increase the heat preservation performance and can reduce the power consumption of the single crystal furnace by 2 kw.

[0022] The original heat preservation cylinder structure in the single crystal furnace is an upper heat preservation cylinder, a middle heat preservation cylinder, and a lower heat preservation cylinder. Among them, the lower heat preservation cylinder and the middle heat preservation cylinder are two separate heat preservation cylinders that are respectively rolled with felt and then stacked together. There are obvious gaps at the joints of the outer felts of the two heat preservation cylinders, and a large amount of heat will be lost through these gaps. The present utility model now makes the middle and lower heat preservation cylinders into an integrated structure and wraps them with a high-efficiency felt with a width equal to the total height of the two heat preservation cylinders, making the two heat preservation cylinders and the felts of the two heat preservation cylinders into one body, avoiding heat loss caused by the splicing seams of the felts of the two heat preservation cylinders, strengthening the heat preservation ability in the middle, and experiments have proved that the power consumption can be reduced by 1.5 KW.

[0023] Since the furnace bottom heat preservation layer is composed of soft felt and solid felt stacked layer by layer, there will be splicing seams between each two layers. During the operation of the single crystal furnace, part of the heat at the furnace bottom will be lost through these seams. Therefore, the present utility model designs a downward extended lower heat preservation cylinder, which is nested in the furnace bottom heat preservation layer. Part of the furnace bottom heat preservation layer is inside the inner layer of the lower heat preservation, and part is on the outside. The furnace bottom heat preservation inside plays a major heat preservation role and is wrapped inside the lower heat preservation cylinder, reducing the radial heat loss at the splicing seams of the stacked layers and increasing the heat preservation ability. Experiments have proved that the power consumption can be reduced by 0.8 KW.

[0024] The utility model utilizes the structure of the integrated middle and lower heat preservation cylinders and is equipped with a long outer heat preservation felt. By using the structure in which the lower heat preservation cylinder is adapted to the furnace bottom heat preservation layer, heat loss is effectively reduced, and the power consumption in the production of single crystal furnaces is lowered. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of a heat preservation cylinder for the heat field of a low-power Czochralski single crystal furnace according to an embodiment of the utility model;

[0026] Figure 2 is Figure 1 a top view of the middle and lower heat preservation cylinders;

[0027] Figure 3 is Figure 2 the sectional view taken along line A-A of ;

[0028] In the figure: 1 - upper heat preservation cylinder, 2 - lower heat preservation cylinder, 3 - lower heat preservation cylinder, 4 - lower heat preservation felt, 5 - inner heat preservation cylinder, 6 - heat preservation material, 7 - groove, 8 - furnace bottom heat preservation layer, 9 - bottom heater, 10 - support rod, 11 - crucible support, 12 - crucible, 13 - main heater, 14 - upper heat preservation support ring, 15 - upper heat preservation felt. Detailed Embodiment

[0029] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments; as long as the technical features involved in the various embodiments of the present utility model described below do not conflict with each other, they can be combined with each other. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present utility model. Embodiment 1

[0030] A heat preservation cylinder for the heat field of a low-power Czochralski single crystal furnace provided in this embodiment has a structure as Figure 1 shown, including an upper heat preservation cylinder 1 and a lower heat preservation cylinder 2. The materials of the upper heat preservation cylinder 1 and the lower heat preservation cylinder 2 are both made of C / SiC. The lower heat preservation cylinder 2 is arranged at the lower end of the upper heat preservation cylinder 1. The upper heat preservation cylinder 1 is an upper heat preservation cylinder, and the lower heat preservation cylinder 2 is composed of a middle heat preservation cylinder and a lower heat preservation cylinder 3 that are integrally formed. The lower heat preservation cylinder 3 is located at the lower end of the middle heat preservation cylinder. From top to bottom, they are the upper heat preservation cylinder, the middle heat preservation cylinder, and the lower heat preservation cylinder 3 in sequence. The lower heat preservation cylinder 3 is a double-layer heat preservation cylinder, and the outer layer of the lower heat preservation cylinder 2 is wrapped with a lower heat preservation felt 4, where:

[0031] Refer to ; Figure 2 and 3, the lower heat preservation cylinder 3 is of a double-layer structure. An inner heat preservation cylinder 5 is arranged inside the lower heat preservation cylinder 3 to form a double-layer heat preservation cylinder. The upper end of the inner heat preservation cylinder 5 is flush with the upper end of the lower heat preservation cylinder 3. The lower end of the inner heat preservation cylinder 5 is 175 mm away from the upper surface of the furnace bottom heat preservation layer. A space is left between the lower heat preservation cylinder 3 and the inner heat preservation cylinder 5 to fill with a heat preservation material 6, graphite felt. Grooves 7 are respectively arranged at the positions of two corresponding main heater legs on the inner heat preservation cylinder 5. The edge of the inner heat preservation cylinder 5 extends downward to the inner wall of the lower heat preservation cylinder 3 so that the space between the inner heat preservation cylinder 5 and the lower heat preservation cylinder 3 is a sealed space;

[0032] Refer to Figure 1 , a furnace bottom heat preservation layer 8 is arranged at the bottom end of the lower heat preservation cylinder 2. The upper surface of the furnace bottom heat preservation layer 8 protrudes upward to form a step. The lower heat preservation cylinder 2 is nested on the furnace bottom heat preservation layer 8 through the step. The protruding part in the furnace bottom heat preservation layer 8 is located inside the lower heat preservation cylinder 2;

[0033] The width of the lower heat preservation felt 4 is equal to the height of the lower heat preservation cylinder 2. During specific implementation, it is installed according to the installation method of a single crystal furnace in the prior art. The step height of the furnace bottom heat preservation layer 8 is 50 mm. A protrusion is formed by cutting 50 mm downward from the ring felt of the furnace bottom heat preservation layer 8. The distances between the cover and the bottom heater in the original single crystal furnace remain unchanged. After installing the furnace bottom heat preservation layer 8, the bottom heater 9 is installed on the corresponding electrode. The lower heat preservation cylinder 2 wrapped with the lower heat preservation felt 4 is placed on the furnace bottom heat preservation layer 8 to complete the installation. Then, the installation of the support rod 10, the crucible support 11, the crucible 12 and the main heater 13 is completed in sequence. The upper heat preservation support ring 14 is placed on the lower heat preservation cylinder 2, and then the upper heat preservation cylinder 1 wrapped with the upper heat preservation felt 15 is placed on the upper heat preservation support ring 14 to complete the installation. The installation of the rest of the thermal field is completed;

[0034] The utility model uses a carbon-ceramic heat preservation cylinder. Compared with a heat preservation cylinder made of carbon-ceramic material, it can achieve a power reduction of 1 kw during the equal-diameter production process; using a double-layer heat preservation cylinder, compared with a single-layer one, it can achieve a power reduction of 2 kw during the equal-diameter production process; using the lower heat preservation cylinder, an integral heat preservation cylinder, compared with a separate heat preservation cylinder, it can achieve a power reduction of 1.5 kw during the equal-diameter process; using a power-saving lower heat preservation cylinder and installing it in cooperation with a matching lower heat preservation felt and furnace bottom heat preservation layer can achieve a power reduction of 0.8 kw during the equal-diameter production process, effectively reducing heat loss and lowering the production power consumption of the single crystal furnace.

[0035] In addition to the above embodiments, the utility model can also have other implementation manners. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the utility model.

Claims

1. A heat preservation cylinder for the thermal field of a Czochralski single crystal furnace with low power consumption, comprising an upper layer heat preservation cylinder (1) and a lower layer heat preservation cylinder (2), the lower layer heat preservation cylinder (2) is arranged at the lower end of the upper layer heat preservation cylinder (1), and is characterized in that: The lower heat-insulating cylinder (2) is composed of a middle heat-insulating cylinder and a lower heat-insulating cylinder (3) which are integrally formed. The lower heat-insulating cylinder (3) is located at the lower end of the middle heat-insulating cylinder. The lower heat-insulating cylinder (3) is a double-layer heat-insulating cylinder. A lower heat-insulating felt (4) is wrapped outside the lower heat-insulating cylinder (2). Wherein: The lower heat-insulating cylinder (3) is of a double-layer structure. An inner heat-insulating cylinder (5) is arranged inside the lower heat-insulating cylinder (3) to form a double-layer heat-insulating cylinder. A space is left between the lower heat-insulating cylinder (3) and the inner heat-insulating cylinder (5) to be filled with a heat-insulating material (6). Grooves (7) are respectively arranged at the positions of two corresponding main heater legs on the inner heat-insulating cylinder (5). The edge of the inner heat-insulating cylinder (5) extends downward to the inner wall of the lower heat-insulating cylinder (3) so that the space between the inner heat-insulating cylinder (5) and the lower heat-insulating cylinder (3) is a sealed space; A furnace bottom heat-insulating layer (8) is arranged at the bottom end of the lower heat-insulating cylinder (2). The upper surface of the furnace bottom heat-insulating layer (8) protrudes upward to form a step. The lower heat-insulating cylinder (2) is nested on the furnace bottom heat-insulating layer (8) through the step. The protruding part in the furnace bottom heat-insulating layer (8) is located inside the lower heat-insulating cylinder (2).

2. The heat preservation cylinder for the direct-pulling single crystal furnace thermal field with low power consumption according to claim 1, characterized in that: The heat-insulating material (6) in the lower heat-insulating cylinder (3) and the inner heat-insulating cylinder (5) is graphite felt.

3. The heat insulation cylinder for the CZ single crystal furnace thermal field with low power consumption according to claim 1, characterized in that: The width of the lower heat-insulating felt (4) is equal to the height of the lower heat-insulating cylinder (2).

4. The heat preservation cylinder for the direct-pulling single crystal furnace thermal field with low power consumption according to claim 1, characterized in that: The materials of the upper heat-insulating cylinder (1) and the lower heat-insulating cylinder (2) are both made of C / SiC.

5. The heat preservation cylinder for the direct-pulling single crystal furnace thermal field with low power consumption according to claim 1, characterized in that: The inner heat-insulating cylinder (5) is located at the upper end inside the lower heat-insulating cylinder (3).

6. The heat preservation cylinder for the direct-pull single crystal furnace thermal field with low power consumption according to claim 1, wherein: The upper end of the inner heat-insulating cylinder (5) is flush with the upper end of the lower heat-insulating cylinder (3). The lower end of the inner heat-insulating cylinder (5) is not less than 100 mm away from the upper surface of the furnace bottom heat-insulating layer.

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