Omnibearing demagnetizing field-based demagnetizing system for magnetic shielding device
By using a comprehensive demagnetizing system that combines transverse and longitudinal coils to generate a rotating oscillating magnetic field, the problem of incomplete and disordered magnetic domain distribution in existing technologies is solved, resulting in a more efficient demagnetizing effect and greater stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YICHANG TESTING TECHNIQUE RESEARCH INSTITUTE
- Filing Date
- 2025-12-03
- Publication Date
- 2026-05-01
AI Technical Summary
Existing magnetic shielding devices can only generate oscillating magnetic fields in both positive and negative directions, resulting in incomplete and disordered magnetic domain distribution, poor demagnetization effect, and insufficient stability.
The demagnetizing system employs an all-around demagnetizing field. It generates a rotating, oscillating, attenuating magnetic field through a demagnetizing current signal generator and a demagnetizing coil. By combining transverse and longitudinal coils, it ensures that the magnetic field direction is not limited to two directions, thus achieving a completely disordered arrangement of magnetic domains.
It improved the quality and stability of demagnetization, enhanced the residual magnetism stability of the shielded room, and achieved deep demagnetization.
Smart Images
Figure CN121964322A_ABST
Abstract
Description
A demagnetizing system based on an all-around demagnetizing field magnetic shielding device Technical Field
[0001] This invention relates to the technical field of magnetic field protection and shielding, and in particular to a demagnetization system for a magnetic shielding device based on an all-around demagnetizing field. Background Technology
[0002] Large shielding devices can effectively shield the Earth's magnetic field and artificial magnetic fields, forming a uniform and stable low magnetic field environment inside. However, since the material constituting the shielding layer is a highly permeable metal, it will be magnetized by the environmental magnetic field after long-term use, affecting the internal residual magnetism. Microscopically, this manifests as the orderly arrangement of magnetic domains in the direction of the external magnetic field. Currently, the mainstream demagnetization method for shielding devices is to apply a gradually decaying oscillating current to the shielding layer, generating a corresponding oscillating magnetic field to disrupt the orderly arrangement of magnetic domains, thereby achieving the purpose of demagnetization.
[0003] The oscillating magnetic field of the demagnetizing system is generated by the demagnetizing coil. Current demagnetizing coil designs can only generate oscillating magnetic fields in both positive and negative directions. Therefore, the magnetic domains can only be distributed in both positive and negative directions, with equal magnitude and opposite direction. Macroscopically, there is no residual magnetism, but it does not achieve the optimal scattered and disordered distribution, resulting in poor demagnetizing effect and insufficient stability. Summary of the Invention
[0004] To address the shortcomings of existing technologies and the need for improvement, this disclosure provides a demagnetization system for a magnetic shielding device based on an omnidirectional demagnetizing field. The purpose is to generate an omnidirectional oscillating attenuating magnetic field through demagnetizing current and demagnetizing coils, thereby making the magnetic domain arrangement completely disordered, improving demagnetization efficiency and quality, and enhancing the residual magnetic stability of the shielding room.
[0005] The demagnetizing system of the magnetic shielding device based on the omnidirectional demagnetizing field provided in this disclosure mainly includes: a demagnetizing current signal generating device and a demagnetizing coil, wherein: the demagnetizing current signal generating device is used to generate a set demagnetizing current signal to drive the demagnetizing coil to generate a demagnetizing magnetic field and make the magnetic field rotate continuously, and the total magnetic field strength gradually decays over time, forming an omnidirectional oscillating attenuating demagnetizing magnetic field, thereby realizing the deep demagnetization of the magnetic shielding device.
[0006] Furthermore, the demagnetizing coil includes a transverse coil and a longitudinal coil, wherein the longitudinal coil is used to generate a longitudinal demagnetizing magnetic field, and the transverse coil is used to generate a transverse demagnetizing magnetic field; the demagnetizing current signal generating device simultaneously outputs at least two demagnetizing current signals that drive the magnetic field to rotate, one of which is input to the transverse coil and the other of which is input to the longitudinal coil. The two signals have the same waveform and amplitude, but are 90° out of phase, and the total current signal gradually decays.
[0007] Furthermore, the demagnetizing current signal generation device includes: two function signal generators and two power amplifiers; wherein, the two function signal generators are used to generate two preset demagnetizing current signals, which are connected by a synchronization interface; the two power amplifiers are used to amplify the demagnetizing current generated by the function signal generators to drive the demagnetizing coil; the current I1 generated by function signal generator 1 and the current I2 generated by function signal generator 2 are respectively:
[0008] In the formula, I0 represents the maximum amplitude of the demagnetizing current, ensuring that the magnetic field generated by the demagnetizing coil can saturate the shielding layer with magnetization; H1(t) and H2(t) are the magnetic field rotation signals.
[0009] ω is the rotational speed of the magnetic field; f is the frequency of the demagnetizing current; T is the total demagnetizing time; a is the attenuation factor, used to adjust the rate of magnetic field attenuation.
[0010] Furthermore, the demagnetizing current signal generating device is implemented through a programmable current source or a current generating device controlled by a host computer.
[0011] Furthermore, for shielding devices made of hexahedral high-permeability magnetic materials, transverse and longitudinal demagnetizing coils are evenly arranged on the shielding layer of each face of the shielding device.
[0012] Compared with the prior art, the beneficial effects of this disclosure are: ① By rotating the demagnetizing magnetic field, the demagnetizing field is demagnetized in all directions, so that the direction of the oscillating magnetic field is no longer limited to the direction of the coil, and the final arrangement of the magnetic domains is completely disordered, rather than only in the positive and negative directions of the demagnetizing magnetic field; ② Improve the demagnetizing quality and stability, and enhance the residual magnetic stability of the shielded room; ③ Convenient for engineering implementation. Attached Figure Description
[0013] The above and other objects, features and advantages of this disclosure will become more apparent from the more detailed description of exemplary embodiments of this disclosure taken in conjunction with the accompanying drawings, in which the same reference numerals generally represent the same components.
[0014] Figure 1 is a schematic diagram of a demagnetization system based on an all-around demagnetizing magnetic shielding device according to the present disclosure; Figure 2 is a schematic diagram of the longitudinal and transverse current changes over time; Figure 3 is a schematic diagram of transverse and longitudinal demagnetizing coils arranged on the surface of a hexahedral high-permeability material shielding device; Figure 4 is a schematic diagram of the magnetic field amplitude and oscillation direction generated in the shielding layer during demagnetization; Figure 5 is a schematic diagram of the demagnetizing magnetic field amplitude and oscillation direction changes over time; Figure 6 is a simulation verification of the demagnetizing magnetic field rotation. Detailed Implementation
[0015] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.
[0016] This disclosure provides a demagnetization system for a magnetic shielding device based on an omnidirectional demagnetizing field. The system employs an omnidirectional oscillating attenuating magnetic field to demagnetize the magnetic shielding device, wherein the magnetic field rotation is achieved by modulating the demagnetizing current signal in conjunction with a demagnetizing coil.
[0017] In one exemplary embodiment, a demagnetizing system according to this disclosure, as shown in FIG1, comprises a function signal generator, a power amplifier, and a demagnetizing coil. Two signal generators are used to generate the designed demagnetizing current signal and are connected by a synchronous interface (SYNC). Two power amplifiers are used to amplify the demagnetizing current generated by the signal generators to drive the demagnetizing coil. The demagnetizing coil consists of a transverse coil and a longitudinal coil, and is used to convert the demagnetizing current into a magnetic field to demagnetize the shielding device.
[0018] Two signal generators are connected via a SYNC interface. The current waveforms and amplitudes they generate are the same, but the current phases are 90° apart. The current I1 generated by signal generator 1 is shown in equation (1), and the current I2 generated by signal generator 2 is shown in equation (2).
[0019]
[0020] In the formula, I0 is the maximum amplitude of the demagnetizing current, which ensures that the magnetic field generated by the demagnetizing coil can saturate the shielding layer; H1(t) and H2(t) are the magnetic field rotation signals; ω is the magnetic field rotation speed; f is the frequency of the demagnetizing current; T is the total demagnetizing time; and a is the attenuation factor, which is used to adjust the rate of magnetic field attenuation.
[0021] The final input current to the demagnetizing coil is shown in Figure 2. The magnetic field rotation signals of the transverse and longitudinal currents are used as baseband signals, and the oscillating current is used as carrier frequency signals. The rotating magnetic field signals are 90° out of phase, and the total current signal gradually decays.
[0022] For shielding devices made of hexahedral high magnetic permeability material, transverse and longitudinal demagnetizing coils are evenly arranged on the shielding layer of each face of the shielding device, as shown in Figure 3. The longitudinal coil is used to generate a longitudinal demagnetizing magnetic field, and the transverse coil is used to generate a transverse demagnetizing magnetic field.
[0023] The amplitude and oscillation direction of the magnetic field generated in the shielding layer during demagnetization are shown in Figures 4 and 5. The total magnetic field strength amplitude gradually decreases over time, and the oscillation direction slowly rotates over time, forming an all-round oscillating attenuation demagnetization magnetic field, which makes the magnetic domain sorting completely disordered, thus improving the demagnetization quality and stability.
[0024] In this embodiment, simulation was also performed to verify the demagnetization effect. Magnetic field simulation modeling and calculation were performed using MAXWELL finite element simulation software to verify the designed demagnetizing magnetic field. As shown in Figure 6, the oscillation direction of the demagnetizing magnetic field rotates with time.
[0025] In summary, this embodiment provides a demagnetization system for a magnetic shielding device based on an omnidirectional demagnetizing field. By defining the amplitude, frequency, duration, envelope function, and rotation speed of the demagnetizing current through a signal generator, an omnidirectional demagnetizing field is generated in the shielding layer, achieving deep demagnetization of the shielding device, reducing the residual magnetic field of the shielding device, and improving the stability after demagnetization.
[0026] In this embodiment, a signal generator and a power amplifier are used to generate a specific demagnetizing current signal. This can also be achieved through a programmable current source, a current generating device controlled by a host computer, or other similar methods.
[0027] The above technical solutions are merely exemplary embodiments of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the specific embodiments of the present invention. Therefore, the methods described above are merely preferred and not restrictive.
Claims
1. A demagnetizing system for a magnetic shielding device based on an omnidirectional demagnetizing field, characterized in that, include: A demagnetizing current signal generating device and a demagnetizing coil are provided, wherein: the demagnetizing current signal generating device is used to generate a set demagnetizing current signal, drive the demagnetizing coil to generate a demagnetizing magnetic field, and make the magnetic field rotate continuously. The total magnetic field strength gradually decreases over time, forming an all-round oscillating attenuating demagnetizing magnetic field, thereby achieving deep demagnetization of the magnetic shielding device.
2. The system according to claim 1, characterized in that, The demagnetizing coil includes a transverse coil and a longitudinal coil, wherein the longitudinal coil is used to generate a longitudinal demagnetizing magnetic field and the transverse coil is used to generate a transverse demagnetizing magnetic field; the demagnetizing current signal generating device simultaneously outputs at least two demagnetizing current signals that drive the magnetic field to rotate, one of which is input to the transverse coil and the other of which is input to the longitudinal coil. The two signals have the same waveform and amplitude, but are 90° out of phase, and the total current signal gradually decays.
3. The system according to claim 2, characterized in that, The demagnetizing current signal generation device includes: two function signal generators and two power amplifiers; wherein, the two function signal generators are used to generate two preset demagnetizing current signals, which are connected by a synchronization interface; the two power amplifiers are used to amplify the demagnetizing current generated by the function signal generators to drive the demagnetizing coil; the current I1 generated by function signal generator 1 and the current I2 generated by function signal generator 2 are respectively: In the formula, I0 is the maximum amplitude of the demagnetizing current, which ensures that the magnetic field generated by the demagnetizing coil can saturate the shielding layer; H1(t) and H2(t) are the magnetic field rotation signals; ω is the magnetic field rotation speed; f is the frequency of the demagnetizing current; T is the total demagnetizing time; and a is the attenuation factor, which is used to adjust the rate of magnetic field attenuation.
4. The system according to claim 2, characterized in that, The demagnetizing current signal generation device is implemented through a programmable current source or a current generation device controlled by a host computer.
5. The system according to any one of claims 2-4, characterized in that, For shielding devices made of hexahedral high-permeability magnetic materials, horizontal and vertical demagnetizing coils are evenly arranged on the shielding layer of each face of the shielding device.