JPH0777169B2 - Degausser for structures - Google Patents

Description

The present invention relates to a degaussing device for canceling a magnetic field appearing outside a hollow structure made of a magnetic material such as a ship.

[Prior Art] A ship or the like composed of a magnetic material containing steel material is magnetized to the outside under the influence of geomagnetism during navigation. The magnetism appearing outside the ship is required to be degaussed for a special purpose such as avoiding magnetic detection.

Conventionally, in order to demagnetize a magnetic field appearing outside of a ship or the like made of such a magnetic material, the external magnetic field of the structure has been regularly detected directly at a predetermined place and demagnetized.

[Problems to be solved by the invention] However, in addition to changes in geomagnetism due to course changes, ships are constantly subjected to stress such as waves and water pressure during navigation, so the permanent magnetism of the structure changes and the magnetism that appears outside is always Change.
Therefore, according to the conventional degaussing device, it is substantially difficult to always maintain the optimum degaussing state.

The present invention has been made based on the above requirements, and maintains the external magnetic field in an optimal demagnetization state at all times, even if the magnetism that appears outside during navigation is constantly changing as in the above-mentioned ship. To obtain a degaussing device.

[Means for solving problems]

As the degaussing device, the present invention provides a hollow structure made of a magnetic material with a plurality of degaussing coils which are arranged orthogonally to each other in order to cancel out the magnetism appearing outside thereof. A plurality of magnetic detectors for detecting the surrounding magnetic field are provided, the detection signal of the magnetic detector is introduced into the comparator of the reference magnetic field setter, and the current to the above degaussing coils is based on the deviation signal from the set value. And a control circuit for controlling the.

[Action]

In the above configuration, the magnetic field appearing outside the hollow structure made of a magnetic material and the magnetic field appearing inside the same structure have an extremely strong correlation. Therefore, the magnetic field inside the structure is detected by the magnetic detector. By detecting and comparing the detected value with the preset value of the preset magnetic field setter and controlling the current of the degaussing coil based on the deviation value, the external magnetic field is always minimized. It maintains the demagnetized state.

〔Example〕

The present invention will be described below with reference to one embodiment shown in the drawings.
Is a hollow structure made of a magnetic material such as a ship, and the structure 1 has predetermined positions such as X-axis, Y-axis, and Z-axis corresponding to the left-right direction, the vertical direction, and the depth direction. Are equipped with degaussing coils 1a, 1b, 1c which are arranged orthogonal to each other.

Further, inside the structure 1, there are provided magnetic detectors 2a, 2b, 2c which are arranged orthogonal to each other in the members connected to the structure corresponding to the degaussing coils 1a, 1b, 1c and which detect the magnetic field around them. The detection signals of the magnetic detectors 2a, 2b, 2c are applied to the comparator of the reference magnetic field setting device 3. The deviation signal between the detection signals of the magnetic detectors 2a, 2b, 2c and the set value of the reference magnetic field setting device 3 is introduced into the signal converter 5 via an appropriate amplifier 4 and the signal converter 5
Is applied as the control signal of the control circuit 6 for controlling the current to the degaussing coils 1a, 1b, 1c.

With the above-described structure, when the structure 1 such as the ship is subjected to the influence of the permanent magnetism and the geomagnetism of the structure at the time of navigation to generate magnetism outside, the magnetism also appears in the members inside the structure 1. The magnetic field around this member is detected by the magnetic detectors 2a, 2b, 2c. The detection signal is compared with a set value preset as a value corresponding to the magnetic field appearing outside in the comparator of the reference magnetic field setter 3, and the deviation signal of both is given to the signal converter 5 via an appropriate amplifier 4. Is applied to the control circuit 6 as a predetermined control signal, and the control circuit 6 controls the degaussing coils 1a, 1b, 1c so that required currents flow through the degaussing coils 1a, 1b, 1c. Due to the magnetic force, the magnetic field appearing outside the structure 1 is canceled and demagnetized.

〔The invention's effect〕

As described above, with respect to a hollow structure made of magnetic material, the magnetic field of the internal member corresponding to the magnetic field appearing outside is detected by the magnetic detector, and this detection signal is introduced to the comparator of the reference magnetic field setting unit. By controlling the currents to the plurality of degaussing coils based on the deviation signal from the set value, it is possible to keep the degaussing state of the structure such that the external magnetic field is always zero.

As a result, unlike the conventional method, it is not necessary to periodically detect the demagnetization by directly detecting the external magnetic field at a predetermined place, and for example, when a ship is navigating, it is constantly subjected to stress such as waves and water pressure during the navigation. Even in a structure in which the magnetism appearing in is constantly changing, the required degaussing effect can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of a degaussing device for a structure showing an embodiment of the present invention, and FIG. 2 is a block diagram of an essential part of a degaussing device for a structure. In the figure, 1 is a structure, 1a, 1b, 1c are degaussing coils, 2a, 2b, 2c
Is a magnetic detector, 3 is a reference magnetic field setting device, 4 is an amplifier, 5 is a signal converter, and 6 is a control circuit.

Claims (1)

[Claims] 1. A hollow structure made of a magnetic material is provided with a plurality of degaussing coils which are arranged orthogonally to each other in order to cancel out the magnetism appearing outside thereof, and the magnetic fields around the degaussing coils are also arranged inside. Control that controls the current to the above degaussing coils based on the deviation signal from the set value by providing a plurality of magnetic detectors to detect and introducing the detection signal of the same magnetic detector to the comparator of the reference magnetic field setter A degaussing device for a structure, characterized by comprising a circuit.