CN111948587A - High-temperature stable magnetic resonance sensor magnet structure and measuring device - Google Patents
High-temperature stable magnetic resonance sensor magnet structure and measuring device Download PDFInfo
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- CN111948587A CN111948587A CN202010813206.1A CN202010813206A CN111948587A CN 111948587 A CN111948587 A CN 111948587A CN 202010813206 A CN202010813206 A CN 202010813206A CN 111948587 A CN111948587 A CN 111948587A
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- 230000003068 static effect Effects 0.000 claims abstract description 42
- 239000000758 substrate Substances 0.000 claims abstract description 21
- 230000032683 aging Effects 0.000 claims abstract description 12
- 229910000938 samarium–cobalt magnet Inorganic materials 0.000 claims description 54
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 48
- KPLQYGBQNPPQGA-UHFFFAOYSA-N cobalt samarium Chemical compound [Co].[Sm] KPLQYGBQNPPQGA-UHFFFAOYSA-N 0.000 claims description 48
- 239000002131 composite material Substances 0.000 claims description 27
- 229910052742 iron Inorganic materials 0.000 claims description 24
- 239000012212 insulator Substances 0.000 claims description 23
- 229910001172 neodymium magnet Inorganic materials 0.000 claims description 23
- 230000035699 permeability Effects 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 13
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 claims description 12
- 229910000838 Al alloy Inorganic materials 0.000 claims description 5
- 238000004891 communication Methods 0.000 claims description 4
- 230000003014 reinforcing effect Effects 0.000 claims description 3
- 230000005415 magnetization Effects 0.000 claims 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims 1
- 238000001514 detection method Methods 0.000 abstract description 11
- 238000005259 measurement Methods 0.000 abstract description 4
- 239000012774 insulation material Substances 0.000 abstract description 3
- 230000002708 enhancing effect Effects 0.000 abstract description 2
- 239000011810 insulating material Substances 0.000 description 15
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- 238000010586 diagram Methods 0.000 description 7
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- 230000007613 environmental effect Effects 0.000 description 3
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- 238000004643 material aging Methods 0.000 description 2
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- 239000000306 component Substances 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
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- 229920002379 silicone rubber Polymers 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
- G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
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Abstract
The invention belongs to the technical field of magnetic resonance detection, and relates to a high-temperature stable magnetic resonance sensor magnet structure and a measuring device, which comprises a magnetic conduction substrate, main magnets respectively arranged at four corners of the magnetic conduction substrate, and temperature compensation blocks correspondingly arranged at the outer sides of the main magnets, wherein the main magnets at two sides of a longitudinal gap are oppositely magnetized, the magnetizing directions of the main magnets are vertical to the magnetic conduction substrate below, the temperature compensation blocks at the outer sides of the main magnets are opposite to the magnetizing directions of the main magnets, the magnetic conduction substrate is used for communicating the main magnets at two sides of the longitudinal gap to achieve the purpose of enhancing the static gradient magnetic field at the upper part of the main magnets, the temperature compensation blocks are used for compensating the deviation of the static gradient magnetic field at the upper part of the main magnets due to the temperature rise, the problem that the unilateral magnetic resonance detection of the current insulation material in an aging state lacks a magnet structure with, causing problems with measurement errors.
Description
Technical Field
The invention belongs to the technical field of magnetic resonance detection, relates to a high-temperature stable magnetic resonance sensor magnet structure and a measuring device, and particularly relates to a high-temperature stable magnetic resonance sensor magnet structure and a measuring device for insulation material aging detection.
Background
The composite insulating material (such as a silicon rubber composite insulator) can be aged from the outside to the inside to different degrees in the using process of a power grid, so that the overall electrical insulating property of the material is reduced. The magnetic resonance detection method can realize the field quantitative nondestructive detection of the aging degree of the insulating material by measuring and analyzing the magnetic resonance signal of the insulating material on the region to be detected, and has great application value in the aging detection of the insulating material of the power system.
The main magnet in the unilateral magnetic resonance sensor generates a static magnetic field B with certain strength and gradient on a region to be measured0The method is the basis for detecting the aging degree of the designated layer surface of the insulating material by the magnetic resonance technology. However, the increase of the ambient temperature causes the magnetic moment in the magnetic domain to be disturbed, so that the remanence and the coercive force of the main magnet are reduced, the static magnetic field intensity on the original region to be measured is further significantly reduced, and under the condition that the excitation frequency omega of the magnetic resonance sensor system is not changed, the larmor formula omega is gamma B0The position of the actual region to be measured corresponding to the excitation frequency is changed, so that the position where the insulating material is expected to be detected is not in accordance with the actual detection position, and a measurement error is caused. Generally speaking, the change of the environmental temperature seriously affects the stability of the static magnetic field intensity of the unilateral magnetic resonance sensor in the region to be detected, and the unilateral magnetic resonance detection of the aging state of the insulation material at present lacks a magnet structure with high temperature stability. This patent proposes a high temperature stable form magnetic resonance sensor magnet structure and measuring device for insulating material aging testing, is expected to fill this blank.
Disclosure of Invention
In view of this, the present invention provides a high temperature stable magnetic resonance sensor magnet structure and a measurement apparatus, in order to solve the problem that measurement errors are caused due to the fact that the position of the insulating material to be detected does not coincide with the actual detection position because a magnet structure with high temperature stability is lacking in the unilateral magnetic resonance detection of the aging state of the insulating material at present.
In order to achieve the above object, the present invention provides a high temperature stable magnetic resonance sensor magnet structure, which includes a magnetic conductive substrate, main magnets respectively disposed at four corners of the magnetic conductive substrate, and temperature compensation blocks correspondingly disposed at outer sides of the main magnets, wherein the main magnets at two sides of a longitudinal slot are oppositely magnetized, and the magnetizing direction is perpendicular to the lower magnetic conductive substrate, the temperature compensation blocks at the outer sides of the main magnets are opposite to the magnetizing direction of the main magnets, the magnetic conductive substrate connects the main magnets at two sides of the longitudinal slot, so as to enhance the static gradient magnetic field at the upper portion of the main magnets, and the temperature compensation blocks are used for compensating the deviation of the static gradient magnetic field at the upper portion of the main magnets caused by the.
The beneficial effect of this basic scheme lies in: the magnetizing directions of a pair of main magnets on two sides of the longitudinal gap are opposite, so that the static gradient magnetic fields generated by the main magnets are communicated, and the static gradient magnetic fields on the upper parts of the main magnets are strengthened. The two pairs of main magnets generate static gradient magnetic fields on the magnetic conduction substrate in the same direction, and the static gradient magnetic fields on the upper parts of the main magnets are further strengthened. The vertical direction of the static gradient magnetic field is the static gradient magnetic field required by the magnet structure measuring device. The temperature compensation block has larger change along with the temperature and magnetic field intensity, and can compensate the attenuation of the static gradient magnetic field at the upper part of the main magnet caused by the temperature rise.
Furthermore, the four main magnets are completely same in geometric dimension and are centrosymmetric cubic samarium-cobalt main magnets, and the four main magnets are distributed in a U shape. Has the advantages that: the geometric dimensions of the main magnets are completely the same, so that the static gradient magnetic field generated on the magnetic conduction substrate has good reinforcing effect.
Further, the temperature compensation block is made of a material with a negative magnetic permeability temperature coefficient or a temperature coefficient of remanence far larger than that of the samarium-cobalt main magnet. Has the advantages that: the stability of the static gradient magnetic field above the main magnet is facilitated by the material having a negative temperature coefficient of permeability or remanence much greater than that of a samarium-cobalt main magnet.
Further, the temperature compensation block is iron with negative permeability temperature coefficient or neodymium iron boron with remanence temperature coefficient far larger than that of the samarium cobalt main magnet. Has the advantages that: the stability of the static gradient magnetic field at the upper portion of the main magnet is facilitated by the iron with a negative temperature coefficient of permeability or neodymium iron boron with a temperature coefficient of remanence much greater than that of a samarium cobalt main magnet.
Furthermore, the magnetic conduction substrate is an iron substrate. Has the advantages that: the iron substrate can provide a magnetic field channel for the communication of the whole main magnet, so that the magnetic energy is fully utilized.
Furthermore, the magnetic conductive substrate is a cuboid-shaped iron yoke and completely covers the bottoms of the main magnet and the temperature compensation block. Has the advantages that: the magnetic conductive substrate completely covering the bottoms of the main magnet and the temperature compensation block is convenient for providing a magnetic field channel for communication of the whole main magnet, so that magnetic energy is fully utilized.
A measuring device based on a high-temperature stable magnetic resonance sensor magnet structure comprises a radio frequency unit and the magnet structure according to any one of the above alternatives, wherein the magnet structure is used for generating a uniform magnetic field for a region to be measured of a composite insulator and polarizing the region to be measured of the composite insulator; the radio frequency unit is used for transmitting a radio frequency pulse magnetic field to the region to be tested of the composite insulator, exciting polarized atoms in the region to be tested of the composite insulator, receiving and collecting generated magnetic resonance signals, and analyzing the aging degree of the region to be tested of the composite insulator conveniently according to the magnetic resonance signals.
Further, an aluminum alloy fixing frame is sleeved outside the magnet structure. Has the advantages that: the aluminum alloy fixing frame is used for placing the magnet structure.
The invention has the beneficial effects that:
the structural design of a main magnet in the existing unilateral magnetic resonance measuring device focuses on the uniformity of a static magnetic field of a region to be measured, and the influence of environmental temperature change on the static magnetic field strength of the region to be measured is ignored. When the measured environment temperature rises, the actually detected distance between the layer surface of the composite insulating material and the surface of the material has an error with the set distance, so that the aging state evaluation of the composite insulating material has a deviation. According to the magnet structure of the high-temperature stable magnetic resonance sensor, the temperature compensation material is used for compensating the deviation of the static magnetic field intensity on the region to be measured caused by the change of the environmental temperature, so that the static main magnetic field intensity has a lower temperature coefficient in the region to be measured, namely higher temperature stability, the aging state of the specified layer of the composite insulating material can be accurately measured by the unilateral magnetic resonance sensor at different temperatures, and the magnet structure of the high-temperature stable magnetic resonance sensor is simple in structure and high in applicability.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.
Drawings
For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic structural diagram of a measuring device for measuring a composite insulator based on the magnet structure of the high temperature stable magnetic resonance sensor of the present invention;
FIG. 2 is a schematic diagram of a magnet structure of a high temperature stable magnetic resonance sensor according to the present invention;
FIG. 3 is a general schematic diagram of a high temperature stable magnetic resonance sensor magnet structure of the present invention using iron with a negative temperature coefficient of permeability as a temperature compensation material;
FIG. 4 is an overall schematic diagram of a high temperature stable magnetic resonance sensor magnet structure of the present invention using neodymium iron boron having a temperature coefficient of remanence much greater than that of the samarium cobalt primary magnet as a temperature compensation material.
Reference numerals: the combined type three-dimensional permanent magnet comprises an iron yoke 1, a samarium-cobalt main magnet I2, a samarium-cobalt main magnet II3, a samarium-cobalt main magnet III4, a samarium-cobalt main magnet IV5, a temperature compensation block I6, a temperature compensation block II7, a temperature compensation block III8, a temperature compensation block IV9, a composite insulator 10, a fixed frame 11 and a magnet structure 12.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.
Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not an indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes, and are not to be construed as limiting the present invention, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.
As shown in fig. 2, the high temperature stable magnetic resonance sensor magnet structure includes a magnetic conductive substrate, main magnets respectively disposed at four corners of the magnetic conductive substrate, and temperature compensation blocks correspondingly disposed at outer sides of each main magnet, wherein the magnetic conductive substrate is a rectangular yoke 1 and completely covers bottoms of the main magnets and the temperature compensation blocks. The yoke 1 completely covering the bottom of the main magnet and the temperature compensation block is convenient for providing a magnetic field channel for the communication of the whole main magnet, so that the magnetic energy is fully utilized, and the thickness of the yoke can achieve the required magnetic conduction effect and needs to be set by combining the shape and the size of the detected insulating material. The four main magnets are completely same in geometric dimension and are centrosymmetric cubic samarium-cobalt main magnets, and the four main magnets are distributed in a U shape. The geometric dimensions of the main magnets are completely the same, so that the static gradient magnetic field generated on the iron yoke 1 has a good reinforcing effect.
The main magnets on two sides of the longitudinal gap are reversely magnetized, the magnetizing directions of the main magnets are perpendicular to the lower iron yoke 1, the temperature compensation blocks on the outer side of each main magnet are opposite to the magnetizing directions of the main magnets, the iron yokes 1 are communicated with the main magnets on two sides of the longitudinal gap to fulfill the aim of enhancing the static gradient magnetic field on the upper portion of the main magnets, and the temperature compensation blocks are used for compensating the deviation of the static gradient magnetic field on the upper portion of the main magnets caused by the rise of temperature. The temperature compensation block is made of iron with negative magnetic permeability temperature coefficient or neodymium iron boron with the remanence temperature coefficient far larger than that of the samarium-cobalt main magnet. The stability of the static gradient magnetic field at the upper portion of the main magnet is facilitated by the iron with a negative temperature coefficient of permeability or neodymium iron boron with a temperature coefficient of remanence much greater than that of a samarium cobalt main magnet.
Specifically, the samarium-cobalt main magnets at four corners of the iron yoke 1 are samarium-cobalt main magnets I2, samarium-cobalt main magnets II3, samarium-cobalt main magnets III4 and samarium-cobalt main magnets IV5 in a counterclockwise sequence, the samarium-cobalt main magnets I2 and the samarium-cobalt main magnets II3 are a group, and the samarium-cobalt main magnets III4 and the samarium-cobalt main magnets IV5 are a group. The upper ends of the samarium cobalt main magnets II3 and the samarium cobalt main magnets III4 on the left side are S poles, the lower ends are N poles, the magnetizing direction is along the-z axis, the upper ends of the samarium cobalt main magnets I2 and the samarium cobalt main magnets IV5 on the right side are N levels, and the lower ends are S levels, namely, the magnetizing direction is along the + z axis. The two groups of main magnets generate a static gradient magnetic field horizontally along a-y axis on a region to be measured of the composite insulator 10, and the gradient direction of the static gradient magnetic field is along a + z axis direction, so that the static gradient magnetic field required by the unilateral magnetic resonance measuring device is formed.
Each cube-shaped temperature compensation block is arranged at the outer side of the corresponding samarium-cobalt main magnet, and the four temperature compensation blocks have the same geometric dimension, are centrosymmetric and are distributed in a U shape; the temperature compensation device sequentially comprises a temperature compensation block I6 corresponding to a samarium cobalt main magnet I2, a temperature compensation block II7 corresponding to a samarium cobalt main magnet II3, a temperature compensation block III8 corresponding to a samarium cobalt main magnet III4 and a temperature compensation block IV9 corresponding to a samarium cobalt main magnet IV 5. The samarium-cobalt main magnet is opposite to the magnetizing direction of the corresponding temperature compensation block.
The temperature compensation block may be a material with a negative permeability temperature coefficient, such as iron, at this time, when the temperature rises, the residual magnetism of the samarium-cobalt magnet is reduced, which results in a reduction in the horizontal static magnetic field strength on the region to be measured of the composite insulator 10, but because the permeability of iron is also reduced, the permeability is reduced, the capability of guiding the magnetic field generated by the samarium-cobalt main magnet to be close to is reduced, which is equivalent to releasing a part of the magnetic field generated by the samarium-cobalt main magnet to the region to be measured, thereby compensating for the reduction in the horizontal static magnetic field strength of the region to be measured caused by the temperature rise, and the situation of the ambient temperature reduction. The change of the attraction capacity of iron to the magnetic field at different temperatures ensures that the whole magnet system keeps the stability of the horizontal static magnetic field strength of the region to be measured at different temperatures; the temperature compensation material can also be a material with a temperature coefficient of remanence much larger than that of the samarium-cobalt main magnet, such as neodymium iron boron (NdFeB), the neodymium iron boron magnet is composed of two pairs of cubic neodymium iron boron (NdFeB) magnets with magnetizing directions respectively in reverse parallel, the magnetizing directions of each neodymium iron boron magnet and the adjacent samarium-cobalt magnet are just opposite, for example, the upper end of the adjacent samarium-cobalt magnet is S-level, the lower end of the adjacent samarium-cobalt magnet is N-level, the upper end of the neodymium iron boron magnet at the outer side of the neodymium iron boron magnet is N-level, and the lower end of the neodymium iron boron magnet at the outer side of the neodymium iron boron magnet is S-level, wherein a pair of samarium-cobalt magnets with smaller temperature coefficient of remanence generate a horizontal leftward static main magnetic field in the region to; with the rise of the temperature, the magnetic field intensity of the region to be detected and the magnetic field intensity of the neodymium iron boron magnet in the region to be detected are reduced, when the reduction of the two magnetic field intensities is the same, the total leftward static magnetic field intensity of the region to be detected is the same before and after the temperature change, the situation of high temperature is opposite to the situation of high temperature, and finally the neodymium iron boron with a larger remanence temperature coefficient enables the whole magnet system to keep the stability of the horizontal static magnetic field intensity of the region to be detected at different temperatures.
The measuring device based on the high-temperature stable magnetic resonance sensor magnet structure comprises a radio frequency unit and the magnet structure 12, wherein the magnet structure 12 is used for generating a uniform magnetic field for a region to be measured of the composite insulator 10 and polarizing the region to be measured of the composite insulator 10; the radio frequency unit is used for emitting a radio frequency pulse magnetic field to the region to be detected of the composite insulator 10, exciting polarized atoms in the region to be detected of the composite insulator 10, receiving and collecting generated magnetic resonance signals, changing the position of the region to be detected on the insulating material along the z axis, analyzing the aging degree of the region to be detected of the composite insulator 10 according to the magnetic resonance signals, and setting the distance between the region to be detected and the upper surface of the magnet structure 12 according to actual needs.
As shown in fig. 1, a schematic structural diagram of a measuring device based on a magnet structure 12 of a high-temperature stable magnetic resonance sensor is used for measuring a composite insulator 10, an aluminum alloy fixing frame 11 is sleeved outside the magnet structure 12, a radio frequency unit is installed on the upper portion of the magnet structure 12, the aluminum alloy fixing frame 11 for placing the magnet structure 12 is tightly attached to the surface of an umbrella skirt of the composite insulator 10, the magnet structure 12 is a core component of the measuring device, the magnet structure 12 is used for generating a static gradient magnetic field on a region to be measured 4 within a specified depth from the surface of the umbrella skirt, and the aging state of the composite insulator 10 at the specified depth is detected by detecting and analyzing a magnetic resonance signal of an insulating material on the region to.
FIG. 3 is a generalized schematic diagram of a high temperature stable magnetic resonance sensor magnet structure 12 using iron with a negative temperature coefficient of permeability as a temperature compensation material; FIG. 3 is a front view of FIG. 2, at a temperature T1, with the sum of the magnetic fields from the top surface of the samarium cobalt main magnet IV5 taken to be B, producing a portion of the magnetic field B1A closed magnetic circuit is formed with the samarium-cobalt main magnet III4, and a horizontal static gradient magnetic field is generated on a region to be measured right above the magnet system; another part of the magnetic field B in the samarium-cobalt main magnet IV5 is due to the high permeability of the iron temperature compensation block IV9 (iron) with permeability μ2Then a loop is formed via the iron, which can be abbreviated as B1＝B-B2. When the ambient temperature rises to T2, the remanence and coercive force of the samarium-cobalt main magnet III4 and the samarium-cobalt main magnet IV5 are reduced, B is reduced, meanwhile, the magnetic permeability mu of iron is reduced due to the rise of the temperature, the magnetic permeability is reduced, the magnetic field passing through the iron in the magnetic block is reduced, namely B is B2And decreases. Selecting proper composition parameters and geometric dimensions of samarium-cobalt main magnet and iron to reduce B and B2The same amount of decrease, i.e. B1c＝(B-ΔB)-(B2-ΔB2)＝B1. The magnetic block can also be understood as the environment temperature is increased, so that the specific gravity of the magnetic field passing through the region to be measured in the magnetic block is increased, and the magnetic block can compensateThe reduction of the remanence of the magnet brings the reduction of the magnetic field strength of the region to be tested, and finally the whole magnet system has the stability of the static magnetic field at high temperature in the region to be tested.
Fig. 4 is an overall schematic diagram of a high temperature stable magnetic resonance sensor magnet structure 12 using neodymium iron boron having a temperature coefficient of remanence much greater than that of the samarium cobalt primary magnet as a temperature compensation material. a represents a static magnetic field B generated in a region to be measured when a samarium-cobalt main magnet acts alone1The direction is leftward; b represents the static magnetic field B generated in the region to be measured when the NdFeB magnet acts alone2And the direction is to the right. When the two magnets are combined together and the neodymium iron boron magnet is positioned outside the samarium cobalt magnet, as shown in fig. c, the samarium cobalt main magnet has stronger magnetic field intensity in the region to be measured and is the main magnet in the magnet system; the stability of the magnetic field temperature of the neodymium iron boron is poor, the temperature compensation in the magnetic flux of the magnet is fast, and the static magnetic field of the area to be measured is B0＝B1-B2. The performance of the two magnets is reduced to different degrees along with the rise of the temperature, and the temperature stability of the compensation magnet is poorer than that of the main magnet B2Decrease faster than B1At this time B0c＝(B1-ΔB1)-(B2-ΔB2). It can be seen that when the proper composition parameters and geometric dimensions of the samarium-cobalt main magnet and the neodymium-iron-boron are selected, the temperature change generates the magnetic field change delta B in the region to be measured for the two magnets1＝ΔB2When, B0＝B0cI.e. the magnetic field strength of the region to be measured is not changed. Therefore, the two magnets are used in cooperation, and the proportion of the two magnets can be changed by utilizing different temperature stability of the two magnets, so that the purpose of improving the temperature stability of the magnet structure 12 is achieved.
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.
Claims (8)
1. The utility model provides a high temperature stable form magnetic resonance sensor magnet structure, a serial communication port, including a magnetic conduction base, place the main magnet in magnetic conduction base four corners department respectively and correspond the temperature compensation piece of placing in every main magnet outside, the main magnet of longitudinal slot both sides is for reverse magnetization and magnetization direction and perpendicular with the magnetic conduction base in below, the temperature compensation piece in every main magnet outside is opposite with this main magnet magnetization direction, the magnetic conduction base is with the main magnet UNICOM of longitudinal slot both sides, play the purpose of reinforcing main magnet upper portion static gradient magnetic field, the temperature compensation piece is used for remedying the temperature rise and brings the decay of main magnet upper portion static gradient magnetic field.
2. The high temperature stable magnetic resonance sensor magnet structure of claim 1, wherein the four main magnets are substantially identical in geometry and are centrosymmetric cubic samarium cobalt main magnets, the four main magnets being distributed in a U-shape.
3. The high temperature stable magnetic resonance sensor magnet structure of claim 1, wherein the temperature compensation block is a material having a negative temperature coefficient of permeability or a temperature coefficient of remanence that is greater than a samarium cobalt main magnet.
4. The high temperature stable magnetic resonance sensor magnet structure of claim 1, wherein the temperature compensation block is iron with a negative temperature coefficient of permeability or neodymium iron boron with a temperature coefficient of remanence greater than that of a samarium cobalt main magnet.
5. The high temperature stable magnetic resonance sensor magnet structure of claim 1, wherein said magnetically conductive substrate is a ferrous substrate.
6. The high temperature stable magnetic resonance sensor magnet structure of claim 1, wherein said magnetically conductive substrate is a rectangular parallelepiped shaped yoke and completely covers the bottom of the main magnet and the temperature compensation block.
7. A measuring device based on a high-temperature stable magnetic resonance sensor magnet structure, which is characterized by comprising a radio frequency unit and the magnet structure according to any one of claims 1 to 6, wherein the magnet structure is used for generating a uniform magnetic field for a region to be measured of a composite insulator and polarizing the region to be measured of the composite insulator; the radio frequency unit is used for transmitting a radio frequency pulse magnetic field to the region to be tested of the composite insulator, exciting polarized atoms in the region to be tested of the composite insulator, receiving and collecting generated magnetic resonance signals, and analyzing the aging degree of the region to be tested of the composite insulator conveniently according to the magnetic resonance signals.
8. The high temperature stable magnetic resonance sensor magnet structure of claim 7, wherein an aluminum alloy frame is sleeved around the magnet structure.
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| CN115420765A (en) * | 2022-09-02 | 2022-12-02 | 国网湖北省电力有限公司超高压公司 | Composite insulator aging nuclear magnetic relaxation spectrum characteristic spectrum searching and analyzing method |
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