Combined heat shield

Abstract

The utility model relates to the technical field of Czochralski single crystal furnaces, in particular to a combined heat shield which comprises a barrel and a flange fixedly connected to the top of the barrel, the barrel is composed of an upper straight barrel, a conical barrel and a lower straight opening, the bottom of the upper straight barrel is fixedly connected with the top of the conical barrel, and the bottom of the conical barrel is fixedly connected with the lower straight opening; the conical cylinder is composed of an upper conical part and a lower conical part, and the joint part between the upper conical part and the lower conical part is of an overlapped structure and is riveted with each other through a rivet; according to the combined heat shield, under the condition of fully considering the physical properties of different metal materials, by combining the characteristic of different temperature gradients caused by different use parts of a heat shield product in a single crystal furnace, a single structure of all molybdenum is changed into a combined form of molybdenum and stainless steel, so that the material cost of the heat shield product can be greatly reduced; and on the premise that the existing use requirements are met, the purchase price of a single product is greatly reduced, and the production and use cost can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of Czochralski single crystal furnaces, in particular to a combined heat shield. Background Art

[0002] The heat shield product is one of the thermal field accessories in the single crystal pulling furnace. Similar products include graphite heat shield, quartz heat shield, and all-molybdenum heat shield. The existing all-molybdenum heat shield is a single structure with molybdenum as the whole material. However, as the price of molybdenum powder has been high in the past two years, the price of molybdenum heat shield has increased by two to three times compared with the initial promotion of molybdenum heat shield. The raw material cost of heat shield products accounts for nearly 80% of the total price of the product, which in turn increases the production cost of the product. Utility Model Content

[0003] In view of the deficiencies of the prior art, the utility model provides a combined heat shield, which solves the technical problem that the existing all-molybdenum heat shield is expensive and thus leads to high production costs.

[0004] In order to solve the above technical problems, the utility model provides the following technical solutions: a combined heat shield, comprising a cylinder and a flange fixedly connected to the top of the cylinder, wherein the cylinder is composed of an upper straight cylinder, a conical cylinder and a lower straight opening, the bottom of the upper straight cylinder is fixedly connected to the top of the conical cylinder, and the bottom of the conical cylinder is fixedly connected to the lower straight opening;

[0005] The cone cylinder consists of an upper cone part and a lower cone part. The joint between the upper cone part and the lower cone part is an overlapping structure and is riveted to each other by rivets.

[0006] Preferably, the lower straight opening and the lower cone are made of molybdenum, and have a height of 250 mm to 300 mm and a thickness of 1 mm.

[0007] Preferably, the upper straight cylinder and the upper cone are made of stainless steel.

[0008] Preferably, the angle formed between the outer conical surfaces of the cone cylinder is 15° to 25°.

[0009] Preferably, the flange consists of an inner ring and an outer ring, and the inner ring and the outer ring are riveted to each other.

[0010] Preferably, the material of the inner ring is stainless steel, and the material of the outer ring is molybdenum.

[0011] By means of the above technical solution, the utility model provides a combined heat shield, which has at least the following beneficial effects:

[0012] 1. This combined heat shield, taking full account of the physical properties of different metal materials and combining the characteristics of different temperature gradients caused by the different use positions of the heat shield products in the single crystal furnace, is changed from a single structure of all molybdenum to a combination of molybdenum and stainless steel. It fully utilizes the advantages of stainless steel materials such as good welding performance, simple molding, light weight, low material price, and sufficient supply, which can greatly reduce the material cost of the heat shield products and is conducive to secondary processing and reuse in the later stage. While meeting the existing use requirements, it greatly reduces the purchase price of a single product and reduces the production and use costs.

[0013] 2. The combined heat shield adopts the form of overlapping riveting for the joint of the upper cone and the lower cone, which is conducive to the replacement and repair of the molybdenum product after damage in the later stage, and is also conducive to the recycling and resale of metal molybdenum. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application:

[0015] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the utility model;

[0016] Figure 2 It is a schematic diagram of the front structure of the utility model in partial section;

[0017] Figure 3 It is a structural schematic diagram of the joint between the upper cone part and the lower cone part of the utility model;

[0018] Figure 4 It is a structural schematic diagram of the flange of the utility model.

[0019] Reference numerals:

[0020] 1. Cylinder body; 11. Upper straight cylinder; 12. Conical cylinder; 121. Upper cone; 122. Lower cone; 13. Lower straight mouth; 14. Rivet; 2. Flange; 21. Inner ring; 22. Outer ring. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] Compared with other similar products, the advantages of molybdenum heat shield are: 1. First of all, molybdenum is a metal material. Although the welding performance is not good, the current processing adopts the method of cutting, forming and riveting molybdenum plates. And it can be reprocessed twice, so it has the advantage of changing the appearance and size of the product for reuse. The production of graphite and quartz heat shields requires the production of molds in advance, the mold cost is high, and the production cycle is long. It is difficult to meet the requirements of frequent changes in the thermal field of crystal pulling manufacturers in the production cycle. 2. In addition, because the molybdenum heat shield is a riveted product. The damage caused during use can be repaired and reused by disassembling and replacing the damaged parts. Other products do not have this feature. 3. Finally, molybdenum is a refractory metal material. When the product is completely scrapped, it can still maintain 40% of the residual value of the original product. Its scrapped materials can be used as additives for steelmaking to produce stainless steel, alloy steel, etc., with high recycling value.

[0023] Based on the technical defects of the existing technology that the production cost is high due to the high price of all-molybdenum heat shield, please refer to Figure 1-Figure 4 The combined heat shield provided by the utility model is changed from a single structure of all molybdenum to a combination of molybdenum and stainless steel, which can greatly reduce the material cost of the heat shield product, is conducive to secondary processing and reuse in the later stage, and greatly reduces the purchase price of a single product while meeting the existing use requirements, and can reduce the production and use costs. It includes a cylinder 1 and a flange 2 fixedly connected to the top of the cylinder 1. The cylinder 1 is composed of an upper straight cylinder 11, a conical cylinder 12 and a lower straight mouth 13. The bottom of the upper straight cylinder 11 is fixedly connected to the top of the conical cylinder 12, and the bottom of the conical cylinder 12 is fixedly connected to the lower straight mouth 13. The cylinder 1 can guide the airflow from the upper part to blow downward, take away the silicon vapor volatilized from the lower crucible, reduce the temperature of the liquid level and the crystal rod, and increase the crystal pulling speed.

[0024] In order to give full play to the simple characteristics of stainless steel processing technology and facilitate the subsequent modification and processing, please refer to Figure 3 The cone 12 is composed of an upper cone 121 and a lower cone 122. The joint between the upper cone 121 and the lower cone 122 is an overlapping structure and is riveted to each other by rivets 14. The overlapping riveting of the joint of the two metals is beneficial to the replacement and repair of the molybdenum product after it is damaged, and is also beneficial to the recovery and resale of metal molybdenum.

[0025] Since the lower part of the heat shield is close to the molten silicon liquid and needs to withstand high temperature for a long time, the material of the lower straight mouth 13 and the lower cone 122 is molybdenum, and the height is 250mm~300mm and the thickness is 1mm. The temperature of this part is relatively high, and the temperature needs to be reduced from about 1000 degrees Celsius to 700 degrees Celsius. High-temperature molybdenum with high value but good high-temperature resistance is selected, which can withstand high temperatures well.

[0026] The temperature in the area more than 250 mm away from the lower mouth has dropped to below 700 degrees Celsius. In order to reduce the production cost of the heat shield, the upper straight tube 11 and the upper cone 121 are made of stainless steel. The use of stainless steel material can avoid metal ion contamination of the stainless steel material caused by high temperature when the temperature is below 700 degrees Celsius, and can also avoid the stainless steel catalysis phenomenon that occurs at 900 degrees Celsius.

[0027] Since the interior of the heat shield is close to the heat exchanger and the crystal rod, in order to facilitate heat conduction and reflect heat to the crystal rod, increase the temperature gradient, increase the pulling speed and reduce electricity costs, the angle formed between the outer cone surfaces of the cone 12 is 15° to 25°, which can better emit heat.

[0028] To facilitate installation of the cylinder 1 , the flange 2 is composed of an inner ring 21 and an outer ring 22 . The inner ring 21 and the outer ring 22 are riveted to each other. The cylinder 1 can be installed in the single crystal furnace through the flange 2 .

[0029] In order to further reduce the cost of the heat shield, the inner ring 21 is made of stainless steel and the outer ring 22 is made of molybdenum. The same combination is also used for the flange 2. The inner ring 21 is in the low temperature zone and stainless steel is used to reduce costs. The outer ring 22 is in the high temperature zone and metal molybdenum can be used to improve heat resistance.

[0030] It can be seen from the above embodiment that: within the range of about 250mm to 300mm in height from the bottom of the product, the lower straight mouth 13 and the lower cone 122 of the heat shield are made of 1mm thick molybdenum material. The temperature of this part is relatively high, and the temperature needs to be reduced from about 1000 degrees Celsius to 700 degrees Celsius. Therefore, high-temperature molybdenum with high value but good high-temperature resistance is selected. The temperature in the area above 13250mm from the lower straight mouth has been reduced to below 700 degrees Celsius. Stainless steel material is used. The same combination method is also used for the flange 2 part. Through such adjustments, a single size ( According to the calculation of products with high quality, the amount of metallic molybdenum can be reduced by about 10 kg. According to the current market price of molybdenum plate (510 yuan / kg), the material cost can be reduced by about 5,100 yuan.

[0031] It should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes 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 apparatus.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Combined heat shield, characterized in that: The invention comprises a cylinder (1) and a flange (2) fixedly connected to the top of the cylinder (1), wherein the cylinder (1) is composed of an upper straight cylinder (11), a conical cylinder (12) and a lower straight opening (13), wherein the bottom of the upper straight cylinder (11) is fixedly connected to the top of the conical cylinder (12), and the bottom of the conical cylinder (12) is fixedly connected to the lower straight opening (13); The cone cylinder (12) is composed of an upper cone portion (121) and a lower cone portion (122); the joint between the upper cone portion (121) and the lower cone portion (122) is an overlapping structure, and the upper cone portion (121) and the lower cone portion (122) are riveted to each other via rivets (14).

2. The combined heat shield according to claim 1, characterized in that: The lower straight opening (13) and the lower cone (122) are made of molybdenum, and have a height of 250 mm to 300 mm and a thickness of 1 mm.

3. The combined heat shield according to claim 1, characterized in that: The upper straight cylinder (11) and the upper cone (121) are made of stainless steel.

4. The combined heat shield according to claim 1, characterized in that: The included angle formed between the outer conical surfaces of the conical cylinder (12) is 15° to 25°.

5. The combined heat shield according to claim 1, characterized in that: The flange (2) is composed of an inner ring (21) and an outer ring (22), and the inner ring (21) and the outer ring (22) are riveted to each other.

6. The combined heat shield according to claim 5, characterized in that: The material of the inner ring (21) is stainless steel, and the material of the outer ring (22) is molybdenum.

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