A permanent magnet device and method for obtaining a magnetic field with high magnetic induction intensity

Abstract

The present invention relates to a permanent magnet device and method for obtaining a high magnetic induction intensity magnetic field, which comprises a permanent magnet (1), a superconducting cavity (2), and a fixing frame (3). The permanent magnet (1) is placed in the superconducting cavity (2) and is connected and fixed by the fixing frame (3). An opening (4) is provided on the superconducting cavity. When the superconducting cavity (2) is in a superconducting state, a high magnetic induction intensity magnetic field higher than the remanent magnetism of the permanent magnet can be obtained at the opening (4). The above method can change the intensity of the magnetic field by switching the superconducting state of the superconducting material. When the superconducting material is in a superconducting state, a high magnetic induction intensity magnetic field is obtained; when the superconducting material is in a normal conducting state, a normal permanent magnetic field environment is obtained. Compared with the prior art, the present invention provides a brand-new method for obtaining a high magnetic induction intensity magnetic field, which has the advantages of simplicity, economy, safety, etc.

Description

Technical Field

[0001] The invention belongs to the field of magnetic fields, and relates to a permanent magnet device and an acquisition method for obtaining a magnetic field with high magnetic induction intensity. Background Art

[0002] Magnetic fields are very common in our daily lives and scientific research. In daily life, we are in the geomagnetic field environment all the time. Magnetic fields are also a very important part of common instruments in life, such as automobiles, electromechanical equipment, and medical devices. In scientific research, magnetic fields are also applied to various fields such as materials, medicine, and machinery. For example, researchers improve the structure and mechanical properties of metals or alloys by applying magnetic fields during the solidification process; and use the magnetic force or magnetocaloric effect generated by magnetic fields for disease treatment or research.

[0003] Magnetic induction intensity is an important parameter to characterize the magnetic field environment. Different magnets have different magnetic induction intensities. Among the two major types of magnets, electromagnets and permanent magnets, electromagnets can obtain a magnetic field of up to tens of Tesla T by using superconducting coils; while the magnetic field generated by permanent magnets themselves generally has a maximum magnetic induction intensity of no more than 1.5T.

[0004] The low magnetic induction intensity limits the application of permanent magnets. For example, in magnetic resonance imaging, in order to obtain better image information, it is necessary to obtain a uniform magnetic field of more than 1.5T in the space environment. Increasing the magnetic induction intensity can improve the imaging resolution. Therefore, the main magnetic field of magnetic resonance imaging is usually provided by electromagnets. In the superconducting magnetic levitation technology that simulates the microgravity environment, superconducting coils are also needed to achieve a large gradient and strong magnetic field environment. However, the method of using electromagnetic coils to obtain a high magnetic induction intensity magnetic field environment is expensive and consumes a lot of energy. In order to ensure the normal operation of the magnet, it is also necessary to continuously cool down, and the later operation cost is high. At the same time, the continuous existence of the strong magnetic field environment leaves a safety hazard.

[0005] In summary, in the prior art, the magnetic induction intensity level that can be obtained by permanent magnets is limited, which cannot give full play to the advantage of permanent magnets without energy consumption, limiting their application scope. The method of using electromagnets to obtain a strong magnetic field environment has problems such as high cost, high energy consumption, and high maintenance cost. It is very necessary to develop new devices and methods that are simple, easy to operate, low cost, and simple to maintain. Summary of the invention

[0006] Technical issues to be solved

[0007] In order to avoid the shortcomings of the prior art, the present invention proposes a permanent magnet device and a method for obtaining a high magnetic induction intensity magnetic field, breaking through the bottleneck of existing permanent magnet technology, and using a simple, economical and safe method to obtain a high magnetic induction intensity magnetic field.

[0008] Technical Solution

[0009] A permanent magnet device for obtaining a high magnetic induction intensity magnetic field, characterized in that it includes a permanent magnet 1, a superconducting cavity 2 and a fixing frame 3; the superconducting cavity 2 with a cavity structure is fixed on the fixing frame 3, and the permanent magnet 1 is built in, and an opening 4 for obtaining a high magnetic induction intensity magnetic field higher than the remanent magnetism of the permanent magnet is provided in the middle of the upper end of the superconducting cavity 2.

[0010] A gap is provided between the permanent magnet 1 and the superconducting cavity 2 .

[0011] The superconducting cavity 2 is made of yttrium barium copper oxide (YBCO) or bismuth strontium calcium copper oxide (BSCCO).

[0012] The permanent magnet includes any permanent magnet including but not limited to a neodymium iron boron permanent magnet.

[0013] The permanent magnet may have any shape including but not limited to cylindrical and square.

[0014] The size of the opening 4 can adjust the magnitude of the high magnetic induction intensity.

[0015] The thickness of the superconducting cavity can adjust the magnitude of the high magnetic induction intensity.

[0016] A method for obtaining a high magnetic induction intensity magnetic field using the permanent magnet device is characterized by: immersing the device in a low-temperature refrigerant, placing the superconducting cavity 4 in a superconducting state, and obtaining a high magnetic induction intensity magnetic field near the superconducting magnet opening 4.

[0017] A low-temperature refrigerant is filled into the main body of the superconducting cavity 2 to obtain a magnetic field with high magnetic induction intensity near the superconducting magnet opening 4 .

[0018] The low temperature refrigerant is liquid nitrogen.

[0019] Beneficial Effects

[0020] The present invention proposes a permanent magnet device and method for obtaining a high magnetic induction intensity magnetic field, which are composed of a permanent magnet 1, a superconducting cavity 2, and a fixing frame 3. The permanent magnet 1 is placed in the superconducting cavity 2 and is connected and fixed by the fixing frame 3. There is an opening 4 on the superconducting cavity. When the superconducting cavity 2 is in a superconducting state, a high magnetic induction intensity magnetic field higher than the remanent magnetism of the permanent magnet can be obtained at the opening 4. The above method can change the intensity of the magnetic field by switching the superconducting state of the superconducting material. When the superconducting material is in a superconducting state, a high magnetic induction intensity magnetic field is obtained; when the superconducting material is in a normal conductive state, an ordinary permanent magnetic field environment is obtained. Compared with the prior art, the present invention provides a new method for obtaining a high magnetic induction intensity magnetic field, which has the advantages of simplicity, economy, and safety.

[0021] The beneficial effects of the present invention are:

[0022] 1. A high magnetic induction intensity magnetic field exceeding the remanence of the permanent magnet is obtained by using a permanent magnet.

[0023] 2. Low cost. First, the cost is low: the present invention uses permanent magnets to provide magnetic fields, and permanent magnets are cheap. Second, the cost of use is low: after the device is processed, no additional energy is required to maintain the magnetism of the magnet; the device does not need to continuously cool the temperature reduction system, which reduces the operating cost.

[0024] 3. Safety. The magnetic field generated by the device of the present invention can be switched between high and low magnetic induction intensity magnetic fields. When a high magnetic induction intensity magnetic field is not needed, the cooling system of the superconducting material is turned off, thereby reducing the potential safety hazards caused by a strong magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a bottom view of a permanent magnet device for obtaining a magnetic field with high magnetic induction intensity.

[0026] Figure 2 It is a southwest isometric view of a permanent magnetic device for obtaining a high magnetic induction intensity magnetic field.

[0027] Figure 3 It is a cross-sectional view of a permanent magnet device for obtaining a magnetic field with a high magnetic induction intensity.

[0028] Figure 4 This is the magnetic field distribution diagram of the AA section of the device in Example 1.

[0029] Figure 5 This is the magnetic field distribution diagram of the AA section of the device in Example 2.

[0030] In the figure, 1 is a magnet; 2 is a superconducting cavity; 3 is a fixed frame; and 4 is an opening. DETAILED DESCRIPTION

[0031] The present invention will now be further described with reference to the embodiments and the accompanying drawings:

[0032] A device for obtaining a high magnetic induction intensity magnetic field using a permanent magnet comprises a permanent magnet 1, a superconducting cavity 2, and a fixing frame 3. The superconducting cavity 2 wraps the permanent magnet 1, a gap is left between the permanent magnet 1 and the superconducting cavity 2, and the superconducting cavity 2 has an opening 4.

[0033] Optionally, the permanent magnet type includes any permanent magnet including neodymium iron boron.

[0034] Optionally, the permanent magnet may be in any shape including cylindrical and square.

[0035] Optionally, the superconducting cavity material types include but are not limited to yttrium barium copper oxide (YBCO) and bismuth strontium calcium copper oxide (BSCCO).

[0036] Optionally, the shape of the superconducting cavity may be any cavity shape.

[0037] Optionally, the size of the permanent magnet and the superconducting cavity as well as the size of the gap can be arbitrarily designed according to the magnetic field requirements.

[0038] Optionally, the fixing frame is used to fix the permanent magnet and the superconducting material.

[0039] A method for obtaining a high magnetic induction intensity permanent magnetic field using the above device is: placing a permanent magnet in a cavity formed by a superconducting material, making the superconducting material in a superconducting state, and obtaining a high magnetic induction intensity magnetic field higher than the remanent magnetism of the permanent magnet at the opening 4 of the superconducting cavity 2.

[0040] Optionally, the method of putting the superconducting material in a superconducting state includes but is not limited to immersing the entire permanent magnet device in a low-temperature refrigerant, or filling the superconducting cavity body with a low-temperature refrigerant.

[0041] Optionally, the adjustment method of the high magnetic induction intensity includes but is not limited to adjusting the thickness of the superconducting cavity and the size of the opening.

[0042] Optionally, switching of the superconducting state of the superconducting cavity changes the strength of the magnetic field. When the superconducting cavity is in the superconducting state, a high magnetic induction intensity magnetic field is obtained; when the superconducting cavity is in the normal conducting state, an ordinary permanent magnetic field environment is obtained.

[0043] Figure 1 The permanent magnet 1 and the superconducting cavity 2 are fixed on the fixing frame 3, the superconducting cavity 2 covers the permanent magnet 1, and a gap is left between the permanent magnet 1 and the superconducting cavity 2.

[0044] Figure 2 It is a southwest isometric view of the device of the present invention. The permanent magnet 1 is covered under the superconducting cavity, the permanent magnet 1 and the superconducting cavity 2 are fixed on a fixing frame 3, and an opening 4 is designed above the superconducting cavity.

[0045] Figure 3 The thickness of the wall of the superconducting cavity 2 is h, the distance between the superconducting cavity 2 and the permanent magnet 1 is d, and the diameter of the opening 4 above the superconducting cavity 2 is D.

[0046] The shapes and sizes of the superconducting cavity, permanent magnet, opening and fixing frame can be designed according to actual needs.

[0047] Example 1

[0048] This embodiment uses Figure 1-3The device design shown is that the cylindrical NdFeB permanent magnet 1 has a diameter of 50mm and a height of 40mm, the permanent magnet remanence is 1.524T, the coercive force is 1096KA / m, the wall thickness of the superconducting cavity 2 is h=1mm, the distance between the superconducting cavity 2 and the permanent magnet 1 is d=1mm, and the diameter of the opening 4 above the superconducting cavity 2 is D=10mm. The superconducting cavity 2 is made of yttrium barium copper oxide YBCO material. The method for obtaining a high magnetic induction intensity permanent magnetic field is:

[0049] Step 1: Process the device according to the design.

[0050] Step 2: Immerse the device in liquid nitrogen to put the superconducting cavity 4 material yttrium barium copper oxide YBCO into a superconducting state, and obtain a high magnetic induction intensity magnetic field near the superconducting magnet opening 4.

[0051] Embodiment 1 Device Figure 2 The magnetic induction intensity distribution of the AA section is as follows Figure 4 As shown, the 10mm spacing position is the location of the opening 4. It can be seen from the figure that the magnetic induction intensity near the opening 4 is 3-6T, and the magnetic induction intensity at a small part is 6-9T, which is much higher than the residual magnetic intensity of the permanent magnet 1.524T, reaching a level that usually requires superconducting magnets, water-cooled magnets or hybrid magnets to achieve.

[0052] Example 2

[0053] This embodiment uses Figure 1-3 The device design shown is that the cylindrical NdFeB magnet 1 has a diameter of 50 mm and a height of 40 mm, a magnet remanence of 1.524 T, a coercive force of 1096 KA / m, a superconducting cavity 2 wall thickness h = 1 mm, a distance d = 1 mm between the superconducting cavity 2 and the magnet 1, and a diameter D = 5 mm of the opening 4 above the superconducting material 2. The superconducting cavity 2 is made of bismuth strontium calcium copper oxide BSCCO material. The method for obtaining a high magnetic induction intensity permanent magnetic field is:

[0054] Step 1: Process the device according to the design.

[0055] Step 2: Fill the superconducting cavity 2 with liquid nitrogen to put the superconducting material bismuth strontium calcium copper oxide BSCCO into a superconducting state, and obtain a high magnetic induction intensity magnetic field at the opening 4.

[0056] Embodiment 2 Device Figure 2 The magnetic induction intensity distribution of the AA section is as follows Figure 5 As shown, the 5mm spacing position is the location of the opening 4. It can be seen from the figure that the magnetic induction intensity near the opening 4 is 5.2-10.4T, and the magnetic induction intensity at a small part is 10.4-15.6T, which is much higher than the residual magnetic intensity of the permanent magnet 1.524T, reaching a level that usually requires superconducting magnets, water-cooled magnets or hybrid magnets to achieve.

Claims

1. A permanent magnetic device for obtaining a high magnetic induction intensity magnetic field, Features The invention comprises a permanent magnet (1), a superconducting cavity (2) and a fixing frame (3); the superconducting cavity (2) having a cavity structure is fixed on the fixing frame (3) and has the permanent magnet (1) built therein; an opening (4) for obtaining a magnetic field with a high magnetic induction intensity higher than the remanent magnetism of the permanent magnet is provided in the middle of the upper end of the superconducting cavity (2); A gap is provided between the permanent magnet (1) and the superconducting cavity (2); The superconducting cavity (2) is made of yttrium barium copper oxide (YBCO) or bismuth strontium calcium copper oxide (BSCCO); The permanent magnet comprises a neodymium iron boron permanent magnet; The device is immersed in a low-temperature refrigerant or the low-temperature refrigerant is filled into the superconducting cavity (2) body, so that the superconducting cavity (2) is in a superconducting state, and a high magnetic induction intensity magnetic field is obtained near the opening (4) of the superconducting cavity; The size of the opening (4) can adjust the magnitude of the high magnetic induction intensity; The thickness of the superconducting cavity can adjust the magnitude of the high magnetic induction intensity.

2. The permanent magnet device for obtaining a high magnetic induction intensity magnetic field according to claim 1, Features: The permanent magnet is cylindrical or square.

3. The permanent magnet device for obtaining a magnetic field with a high magnetic induction intensity according to claim 1, Features: The low temperature refrigerant is liquid nitrogen.

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