Integrated lightweight magnetic control crystal pulling superconducting magnet

Abstract

The utility model discloses an integrated light-weight magnetic control crystal pulling superconducting magnet which comprises a vacuum cavity inner cylinder, a magnetic shielding vacuum cavity, reinforcing ribs, a cold shield, a superconducting coil, a refrigerating machine and a current lead. A crystal pulling furnace is arranged in the vacuum cavity inner cylinder and comprises a crystal pulling furnace lower furnace cylinder and a furnace cover. The lower furnace barrel and the furnace cover of the crystal pulling furnace are respectively provided with a vacuum cavity inner barrel, the upper part and the lower part of the vacuum cavity inner barrel are respectively provided with a sealing chuck interface, and the vacuum cavity inner barrel is hermetically connected with the lower furnace barrel and the furnace cover of the crystal pulling furnace through the sealing chuck interfaces. Design, manufacturing and installation of a bearing lifting rack attached to the superconducting magnet and concentric installation of the superconducting magnet and the crystal pulling furnace are omitted. And the weight of the superconducting coil assembly is reduced, convenience and rapidness are achieved, and cost is low.

Description

Technical Field

[0001] The utility model relates to the technical field of crystal pulling furnaces, and in particular to an integrated lightweight magnetically controlled crystal pulling superconducting magnet. Background Art

[0002] High-purity single crystal silicon is widely used in solar cells, integrated circuits, semiconductors and other industries, and is a key material for high-tech industries such as photovoltaic power generation and electronic information. The magnetron direct-pull single crystal technology (MCZ) has become a necessary means to grow large-diameter high-purity single crystal silicon, which can more effectively suppress thermal convection and reduce oxygen content. Although superconducting magnets have significantly improved the quality of single crystal growth, the prices of superconducting magnets and their associated load-bearing lifting frames remain high: the current liquid helium-free superconducting magnets on the direct-pull single crystal market, semiconductor-grade superconducting magnets, and photovoltaic-grade superconducting magnets are priced at around 5 million yuan, and 2 million yuan, accounting for too large a proportion of the total price of crystal pulling equipment, making it difficult to effectively promote them on a large scale; and the volume of non-magnetic field crystal pulling furnaces on the market is huge, and manufacturers have the need to transform them into magnetron crystal pulling, but the initial infrastructure of the crystal pulling furnace station cannot meet the installation of the load-bearing lifting frame attached to the superconducting magnet, and it is difficult to transform the existing crystal pulling furnace.

[0003] Currently, superconducting magnets are designed independently from crystal pulling furnaces, and the two are used in a nested manner. When designing superconducting magnets, factors such as the matching installation margin and concentric adjustment of the crystal pulling furnace must be considered. In addition, a separate load-bearing lifting frame must be designed for the superconducting magnets, which increases design and manufacturing costs, makes the total price of magnetically controlled CZ single crystal pulling equipment relatively high, and makes the overall installation of the equipment inconvenient. Utility Model Content

[0004] The embodiment of the utility model provides an integrated lightweight magnetron crystal pulling superconducting magnet, which is used to solve the problems in the prior art that the total price of magnetron CZ single crystal pulling equipment is relatively high and the overall installation convenience of the equipment is not enough.

[0005] On the one hand, the embodiment of the utility model provides an integrated lightweight magnetron crystal pulling superconducting magnet, including: a superconducting magnet, the superconducting magnet including: a vacuum chamber inner cylinder, a magnetic shielding vacuum chamber, reinforcing ribs, a cold shield, a superconducting coil, a refrigerator and a current lead;

[0006] The outer side of the superconducting coil is surrounded by a magnetic shielding vacuum chamber, the inner side of the superconducting coil is provided with a vacuum chamber inner cylinder, the vacuum chamber inner cylinder is sealed and connected with the magnetic shielding vacuum chamber, and a cold shield is provided between the vacuum chamber inner cylinder and the magnetic shielding vacuum chamber;

[0007] The superconducting coil is two annular coils symmetrically distributed up and down, wherein the upper annular coil is the upper coil, and the lower annular coil is the lower coil. The upper coil and the lower coil are fixed to the top plate and the bottom plate of the magnetic shielding vacuum chamber by a tie rod. The upper coil and the lower coil are energized in series in reverse according to the direction of the magnetic field. The upper coil and the lower coil are installed in a lightweight load-bearing frame.

[0008] A crystal pulling furnace is arranged in the vacuum chamber inner tube, and the crystal pulling furnace includes a lower furnace tube and a furnace cover of the crystal pulling furnace. Sealing chuck interfaces are arranged above and below the vacuum chamber inner tube, and the vacuum chamber inner tube is sealed and connected with the lower furnace tube and the furnace cover of the crystal pulling furnace through the sealing chuck interfaces.

[0009] In a possible implementation, the vacuum chamber inner tube is sealed and connected to the magnetic shielding vacuum chamber by welding, the vacuum chamber inner tube and the magnetic shielding vacuum chamber are in a high vacuum environment, and the reinforcing ribs are welded at the upper and lower connecting ends of the vacuum chamber inner tube and the magnetic shielding vacuum chamber.

[0010] In a possible implementation manner, the cold shield is fixed up and down on the top plate and the bottom plate of the magnetic shielding vacuum chamber through tie rods.

[0011] In a possible implementation, the lightweight load-bearing frame includes a C-shaped clamp, an inner support and a fixing ring.

[0012] In a possible implementation, the C-shaped clamp constrains the axial electromagnetic force Fz and radial electromagnetic force Fr of the superconducting coil, the inner support positions the spacing of the superconducting coil from the inside, and the fixing ring connects the C-shaped clamp and the inner support to form the lightweight load-bearing frame.

[0013] In a possible implementation, the refrigerator is disposed on the outer side of the top of the magnetic shielding vacuum chamber, and the refrigerator is provided with a primary cold head and a secondary cold head.

[0014] In a possible implementation, the first-level cold head is connected to a cold shield, and the second-level cold head is connected to a superconducting coil.

[0015] In a possible implementation, two current leads are provided, the current leads are fixed to the top of the outer side of the magnetic shielding vacuum chamber, and the two current leads are electrically connected to the positive and negative poles of the total circuit of the superconducting coil respectively.

[0016] The utility model provides an integrated lightweight magnetron crystal pulling superconducting magnet, which has the following advantages:

[0017] (1) The vacuum chamber inner tube of the superconducting magnet is directly used as the crystal pulling furnace tube and the lower furnace tube and furnace cover of the crystal pulling furnace are sealed and connected, eliminating the design, manufacture and installation of the load-bearing lifting frame attached to the superconducting magnet, as well as the concentric installation of the superconducting magnet and the crystal pulling furnace, which can greatly reduce the total price of the superconducting magnet equipment and improve the convenience of overall equipment installation. In actual crystal pulling operations, such as loading and furnace cleaning, there is no need to lift the superconducting magnet separately, which improves the efficiency of crystal pulling operations.

[0018] (2) Reduce the weight of the superconducting coil assembly: Use high-temperature superconducting tape to wind the coil, which has high critical current characteristics and reduces the amount of wire used; demold the coil from the winding frame after epoxy impregnation, and set up a lightweight load-bearing frame to constrain the displacement and strain of the coil caused by the electromagnetic force.

[0019] (3) When refitting, it only needs to replace and install the current crystal pulling furnace barrel without modifying the furnace body infrastructure, which is convenient, fast and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of the structure of an integrated lightweight magnetron crystal pulling superconducting magnet provided in an embodiment of the utility model;

[0022] Figure 2 A detailed cross-sectional view of a superconducting magnet structure of an integrated lightweight magnetron crystal pulling superconducting magnet provided in an embodiment of the utility model;

[0023] Figure 3 A schematic diagram of a lightweight coil bearing frame of an integrated lightweight magnetron crystal pulling superconducting magnet provided in an embodiment of the utility model;

[0024] Figure 4 A schematic diagram showing installation comparison between an integrated lightweight magnetron crystal pulling superconducting magnet and a conventional superconducting magnet provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0025] 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.

[0026] Figure 1 The schematic diagram of the structure of an integrated lightweight magnetron crystal pulling superconducting magnet provided by the embodiment of the utility model. The embodiment of the utility model provides an integrated lightweight magnetron crystal pulling superconducting magnet, including:

[0027] A superconducting magnet 1, comprising: a vacuum chamber inner tube 11, a magnetic shielding vacuum chamber 12, reinforcing ribs 13, a cold shield 14, a superconducting coil 15, a refrigerator 17 and a current lead 18;

[0028] The outer side of the superconducting coil 15 is surrounded by a magnetic shielding vacuum chamber 12, and the inner side of the superconducting coil 15 is provided with a vacuum chamber inner cylinder 11, the vacuum chamber inner cylinder 11 is sealed and connected with the magnetic shielding vacuum chamber 12, and a cold shield 14 is provided between the vacuum chamber inner cylinder 11 and the magnetic shielding vacuum chamber 12;

[0029] The superconducting coil 15 is two annular coils symmetrically distributed up and down, wherein the upper annular coil is the upper coil 151, and the lower annular coil is the lower coil 152. The upper coil 151 and the lower coil 152 are fixed to the top plate and the bottom plate of the magnetic shielding vacuum chamber 12 by a tie rod. The upper coil 151 and the lower coil 152 are energized in series in reverse according to the direction of the magnetic field. The upper coil 151 and the lower coil 152 are installed in a lightweight load-bearing frame 153.

[0030] A crystal pulling furnace 2 is arranged in the vacuum chamber inner tube 11, and the crystal pulling furnace 2 includes a lower furnace barrel 203 and a furnace cover 201 of the crystal pulling furnace. Sealing chuck interfaces are arranged at the upper and lower parts of the vacuum chamber inner tube 11. The vacuum chamber inner tube 11 is sealed and connected with the lower furnace barrel 203 and the furnace cover 201 of the crystal pulling furnace through the sealing chuck interfaces. The vacuum chamber inner tube 11 is sealed and connected with the magnetic shielding vacuum chamber 12 through welding. The interiors of the vacuum chamber inner tube 11 and the magnetic shielding vacuum chamber 12 are high vacuum environments. The reinforcing ribs 13 are welded to the upper and lower connecting ends of the vacuum chamber inner tube 11 and the magnetic shielding vacuum chamber 12. The cold shield 14 is fixed to the top plate and the bottom plate of the magnetic shielding vacuum chamber 12 by pull rods. The lightweight load-bearing frame 153 includes a C-shaped clamp 1531, an inner support 1532 and a fixing ring 1533. The C-shaped clamp 1531 constrains the axial electromagnetic force Fz and the radial electromagnetic force Fr of the superconducting coil 15. The inner support 1532 locates the spacing of the superconducting coil 15 from the inside. The fixing ring 1533 connects the C-shaped clamp 1531 and the inner support 1532 are connected to form the lightweight load-bearing frame 153, the refrigerator 17 is arranged on the outer side of the top of the magnetic shielding vacuum chamber 12, and the refrigerator is provided with a primary cold head and a secondary cold head, the primary cold head is connected to the cold shield 14, and the secondary cold head is connected to the superconducting coil 15. Two current leads 18 are provided, and the current leads 18 are fixed on the top of the outer side of the magnetic shielding vacuum chamber 12, and the two current leads 18 are respectively electrically connected to the positive and negative poles of the total circuit of the superconducting coil 15.

[0031] For example, Figure 1 , 2 As shown in Figure 3, the inner wall of the vacuum chamber inner tube 11 is the crystal pulling furnace tube of the crystal pulling furnace 2. Through this design, the superconducting magnet 1 and the crystal pulling furnace 2 are integrated, eliminating the design, manufacture and installation of the load-bearing lifting frame attached to the superconducting magnet, as well as the concentric installation of the superconducting magnet and the crystal pulling furnace. The lightweight design of the superconducting magnet 1 is achieved through the C-shaped clamp 1531, the inner support 1532 and the fixing ring 1533 of the lightweight load-bearing frame 153, so that the integrated combination of the superconducting magnet 1 and the crystal pulling furnace 2 has lower cost and is more convenient to install.

[0032] In a possible embodiment, the technical solution of combining the existing conventional superconducting magnet with the existing crystal pulling furnace is compared with the technical solution of the integrated lightweight magnetically controlled crystal pulling superconducting magnet of the present application. Figure 4 As shown, the conventional superconducting magnet is nested outside the crystal pulling furnace 2, and an elevator for lifting the superconducting magnet is provided below, so the opening size of the second-floor operating platform needs to be increased to accommodate the installation of the elevator.

[0033] When a conventional superconducting magnet is installed for the first time, it is necessary to ensure that it is concentric with the crystal pulling furnace barrel of the crystal pulling furnace 2, and multiple adjustments are required during the installation process.

[0034] During the furnace loading and cleaning process, the conventional superconducting magnet needs to be lowered to the same level as the second floor ground first, and then the furnace cover 201 and the crystal pulling furnace barrel need to be lifted away before the relevant operations can be carried out inside the furnace.

[0035] The superconducting magnet 1 of the present application does not involve an elevator, because the inner tube 11 of the vacuum chamber of the superconducting magnet 1 is the crystal pulling furnace tube, and the opening size of the second-floor operating platform only needs to meet the installation of the crystal pulling furnace frame, and the size can be reduced a lot; currently, the opening of the second-floor platform of most crystal pulling manufacturers is of this size, and conventional superconducting magnets cannot be installed, but it is very convenient to install the superconducting magnet 1 of the present application.

[0036] The present application also avoids the concentricity problem between the superconducting magnet 1 and the crystal pulling furnace 2 by using the vacuum chamber inner tube 11 as the crystal pulling furnace tube, and the installation can be completed in just one time.

[0037] During the furnace loading and cleaning process, it is only necessary to lift the furnace cover 201 and the crystal pulling furnace barrel (superconducting magnet 1) and then carry out related operations inside the furnace, eliminating the need for lifting and lowering the magnet and improving operating efficiency.

[0038] Compared with the existing technology, taking a single crystal furnace with a size of 160 as an example, the current weight of a conventional superconducting magnet is about 3.5 tons. The superconducting magnet of this application adopts a demolding frameless structure, and only uses a lightweight load-bearing frame 153 for constraints, reducing 2 frame structures (non-magnetic stainless steel), reducing the weight by about 300kg, and reducing material and processing costs by about 30,000 yuan. The superconducting magnet is integrated with the crystal pulling furnace barrel, reducing the inner barrel structure of the magnet vacuum chamber (non-magnetic stainless steel), reducing the weight by about 300kg, and reducing material and processing costs by about 10,000 yuan. In summary, the weight of the magnet is reduced by about 600kg, accounting for 17%; the production cost of the magnet is reduced by about 40,000 yuan.

[0039] The superconducting magnet of this application also saves the elevator, which costs about 500,000 yuan, and saves about 100,000 yuan in infrastructure renovation costs for the crystal pulling furnace. In summary, the whole set of magnetic control crystal pulling furnace saves about 640,000 yuan in costs. At present, there are more than 60,000 non-magnetic field crystal pulling furnaces in the market. If all are converted into integrated superconducting magnets, it is estimated that the total cost will be saved by 38.4 billion yuan.

[0040] Compared with existing technologies, the superconducting magnet of this application omits the coil skeleton and vacuum chamber inner tube processing, which shortens the magnet production cycle by 1 week, accounting for about 20%.

[0041] The initial installation time of conventional superconducting magnet equipment includes 3 days for elevator installation, 2 days for superconducting magnet installation, and 1 day for equipment joint adjustment. The use of the superconducting magnet of the present application saves 3 days of elevator installation time, and saves 1 day of concentric adjustment process of superconducting magnet and crystal pulling furnace installation, saving a total of 4 days of installation time, accounting for 67%.

[0042] In the process of loading and cleaning the furnace during the crystal pulling process, the time of adjusting the magnet lifting position is saved, and the magnet lifting and lowering takes about 10 minutes. The process operation flow is simplified.

[0043] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0044] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An integrated lightweight magnetron crystal pulling superconducting magnet, characterized in that: include: A superconducting magnet (1), the superconducting magnet (1) comprising: a vacuum chamber inner tube (11), a magnetic shielding vacuum chamber (12), reinforcing ribs (13), a cold shield (14), a superconducting coil (15), a refrigerator (17) and a current lead (18); The outer side of the superconducting coil (15) is surrounded by a magnetic shielding vacuum chamber (12), the inner side of the superconducting coil (15) is provided with a vacuum chamber inner cylinder (11), the vacuum chamber inner cylinder (11) is sealedly connected to the magnetic shielding vacuum chamber (12), and a cold shield (14) is provided between the vacuum chamber inner cylinder (11) and the magnetic shielding vacuum chamber (12); The superconducting coil (15) is two annular coils symmetrically distributed up and down, wherein the upper annular coil is an upper coil (151), and the lower annular coil is a lower coil (152); the upper coil (151) and the lower coil (152) are fixed to the top plate and the bottom plate of the magnetic shielding vacuum chamber (12) via a pull rod; the upper coil (151) and the lower coil (152) are energized in series in opposite directions according to the direction of the magnetic field; and the upper coil (151) and the lower coil (152) are installed in a lightweight load-bearing frame (153); A crystal pulling furnace (2) is arranged in the vacuum chamber inner tube (11), and the crystal pulling furnace (2) comprises a lower furnace tube (203) and a furnace cover (201) of the crystal pulling furnace. Sealing chuck interfaces are arranged at the top and bottom of the vacuum chamber inner tube (11), and the vacuum chamber inner tube (11) is sealedly connected with the lower furnace tube (203) and the furnace cover (201) of the crystal pulling furnace via the sealing chuck interfaces.

2. The integrated lightweight magnetron crystal pulling superconducting magnet according to claim 1, characterized in that: The vacuum chamber inner tube (11) and the magnetic shielding vacuum chamber (12) are sealed and connected by welding; the interiors of the vacuum chamber inner tube (11) and the magnetic shielding vacuum chamber (12) are high vacuum environments; and the reinforcing ribs (13) are welded at the upper and lower connecting ends of the vacuum chamber inner tube (11) and the magnetic shielding vacuum chamber (12).

3. The integrated lightweight magnetron crystal pulling superconducting magnet according to claim 1, characterized in that: The cold shield (14) is fixed up and down on the top plate and the bottom plate of the magnetic shielding vacuum chamber (12) via tie rods.

4. The integrated lightweight magnetron crystal pulling superconducting magnet according to claim 1, characterized in that: The lightweight load-bearing frame (153) comprises a C-shaped clamp (1531), an inner support (1532) and a fixing ring (1533).

5. The integrated lightweight magnetron crystal pulling superconducting magnet according to claim 4, characterized in that: The C-shaped clamp (1531) constrains the axial electromagnetic force Fz and the radial electromagnetic force Fr of the superconducting coil (15), the inner support (1532) locates the spacing of the superconducting coil (15) from the inside, and the fixing ring (1533) connects the C-shaped clamp (1531) and the inner support (1532) to form the lightweight load-bearing frame (153).

6. The integrated lightweight magnetron crystal pulling superconducting magnet according to claim 1, characterized in that: The refrigerator (17) is arranged on the outside of the top of the magnetic shielding vacuum chamber (12), and the refrigerator is provided with a primary cold head and a secondary cold head.

7. The integrated lightweight magnetron crystal pulling superconducting magnet according to claim 6, characterized in that: The first-level cold head is connected to a cold shield (14), and the second-level cold head is connected to a superconducting coil (15).

8. The integrated lightweight magnetron crystal pulling superconducting magnet according to claim 1, characterized in that: Two current leads (18) are provided, and the current leads (18) are fixed to the top of the outer side of the magnetic shielding vacuum chamber (12). The two current leads (18) are respectively electrically connected to the positive and negative poles of the total circuit of the superconducting coil (15).

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