KR20230095315A - Wall thickness measurement apparatus of vessel containing conductor - Google Patents

Abstract

The present invention relates to a thickness measuring device for a wall (20) of a container on which an electrically conductive reinforcement (32) is stacked. The disclosed thickness measuring device for a wall (20) of a container, which has an electrically isotropic conductor (30) accommodated therein, the wall (20) formed from an electrically anisotropic conductor, and an electrically conductive reinforcement (32) stacked on the outer surface thereof, comprises: a current supply unit (100) supplying alternating current; an excitation coil (60) mounted between the container wall (20) and the electrically conductive reinforcement (32), and forming a primary magnetic field (80) by the alternating current supplied by the current supply unit (100); a sensing coil (70) mounted between the container wall (20) and the electrically conductive reinforcement (32) to be spaced at a predetermined distance from the excitation coil (60), and sensing a secondary magnetic field (90) induced by an eddy current (50) formed by the primary magnetic field (80); a voltage measurement unit (200) measuring the voltage applied to the sensing coil (70) and transmitting the measured voltage to a control unit (300); and the control unit (300) calculating the thickness of the container wall (20) from the voltage received from the voltage measurement unit (200). The control unit (300) calculates the thickness of the container wall from the secondary magnetic field (90) caused by the eddy current (50) formed when the alternating current is applied. Therefore, the device can accurately measure the thickness of the container wall formed from an electrically anisotropic conductor.

Description

Wall thickness measurement apparatus of vessel containing conductor}

The present invention relates to an apparatus for measuring the thickness of a container wall in which electrically conductive reinforcing materials are laminated, and more particularly, to prevent eddy current from being formed in the electrically conductive reinforcing material by inserting an electromagnetic wave shielding member between a non-conductive medium and the electrically conductive reinforcing material. While blocking the primary magnetic field applied from the coil, the winding direction of the excitation coil is determined so that the primary magnetic field applied by the excitation coil passes through the container wall, which is an anisotropic electrical conductor, and the eddy current caused by the primary magnetic field An apparatus for measuring the thickness of a container wall capable of accurately measuring the thickness of the container wall by sensing only the secondary magnetic field applied and determining the winding direction of the sensing coil so that the primary magnetic field is not sensed.

In industrial settings, various containers are used to accommodate media with various characteristics. Since the container wall is worn out by various physical and chemical reactions with the medium accommodated inside, it is necessary to periodically measure the thickness of the container wall and maintain it.

At this time, it may be difficult to directly measure the thickness of the container wall due to environmental factors such as temperature inside the container and PH.

Conventionally, when the medium accommodated in the container is high temperature, the thickness of the wall was estimated by measuring the temperature of the container wall, but it has not been put into practical use due to poor accuracy.

On the other hand, an acoustic method has been proposed, but it is difficult to generalize because it is expensive and difficult to measure several points at once in analyzing the measured acoustic characteristics.

In particular, when the medium accommodated inside the container is an electrically isotropic material with uniform electrical conductivity in all directions, an electrically conductive reinforcing material is laminated on the outer circumferential surface of the container wall, and the container wall is an electrically anisotropic material with different electrical conductivity depending on the direction In this regard, a reliable method for measuring the thickness of the container wall has not yet been proposed, and a solution to this problem is desperately needed.

Republic of Korea Patent Publication No. 10-2018-0073552

The present invention has been proposed to solve the above problems, and an electrically isotropic conductor is accommodated therein, an electrically conductive reinforcing material is laminated on the outer circumferential surface of the container wall, and the object is to measure the wall thickness of a container formed of the electrically anisotropic conductor. do.

In addition, an object of the present invention is to increase measurement accuracy by allowing the sensing coil to sense only the secondary magnetic field applied by the eddy current formed in the electric isotropic conductor accommodated inside the container and not to sense the primary magnetic field applied by the excitation coil. .

Another object of the present invention is to determine the winding direction of the excitation coil so that the primary magnetic field formed by the excitation coil passes through the container wall, which is an anisotropic conductor.

Another object of the present invention is to block a primary magnetic field applied from an excitation coil by inserting an electromagnetic wave blocking member between the non-conductive medium and the electrically conductive reinforcing material so that eddy currents are not formed in the electrically conductive reinforcing material.

The present invention is an apparatus for measuring the wall thickness of a container in which an electrically isotropic conductor is accommodated inside the container, a wall constituting the container is formed of an electrically anisotropic conductor, and an electrically conductive reinforcing material is laminated on the outer circumferential surface of the container,

a current supply unit supplying an alternating current;

an excitation coil mounted between the container wall and the electrically conductive reinforcing material to form a primary magnetic field by an alternating current applied by the current supply unit;

a sensing coil mounted between the container wall and the electrically conductive reinforcing material at a predetermined distance from the excitation coil and sensing a secondary magnetic field applied by an eddy current formed by the primary magnetic field;

a voltage measurement unit for measuring the voltage applied to the sensing coil and transmitting the measured voltage to a control unit; and

A controller that controls the overall operation of the wall thickness measuring device and calculates the thickness of the container wall from the voltage received from the voltage measuring unit; includes,

The controller calculates the thickness of the container wall from the secondary magnetic field generated by the eddy current formed when the alternating current is applied, and the thickness measuring device for the container wall laminated with the conductive reinforcing material is provided.

Also, in the present invention, the excitation coil and the sensing coil are characterized in that they are disposed between the container wall and the electrically conductive reinforcing material in a state of being embedded in a non-electrically conductive medium.

In addition, in the present invention, an electromagnetic wave blocking member is inserted between the non-conductive medium and the electrically conductive reinforcing material to block the primary magnetic field applied from the excitation coil so that eddy currents do not form in the electrically conductive reinforcing material. do.

In addition, in the present invention, the electromagnetic wave blocking member is characterized in that Permalloy (Permalloy).

In addition, the sensing coil of the present invention is characterized in that it senses a secondary magnetic field by an eddy current formed adjacent to an interface between an electrical isotropic conductor accommodated inside the container and the container wall.

In addition, when the thickness direction of the container wall is defined as the horizontal direction in the present invention, the electrical conductivity of the container wall is maximum in the vertical and horizontal directions, and in the circumferential direction of the wall, which is a direction perpendicular to the vertical and horizontal directions, lowest,

The direction of the winding axis around which the excitation coil is wound is horizontal, and the direction of the winding axis around which the sensing coil is wound is upward and downward,

The sensing coil is characterized in that the voltage applied by the primary magnetic field is not sensed, and only the voltage applied by the secondary magnetic field is sensed.

In addition, in the present invention, the cross-sectional shape of the excitation coil and the sensing coil is rectangular, and the longitudinal direction is the circumferential direction of the wall.

In addition, in the present invention, the sensing coil,

a first sensing coil mounted above the excitation coil between the container wall and the electrically conductive reinforcing material and sensing a secondary magnetic field applied by an eddy current formed by the primary magnetic field; and

A second sensing coil mounted below the excitation coil between the container wall and the electrically conductive reinforcing material and sensing a secondary magnetic field applied by an eddy current formed by the primary magnetic field. to be characterized

In addition, the first sensing coil and the second sensing coil of the present invention are characterized in that they are symmetrically arranged at the same distance from the excitation coil.

According to the present invention, an electrically isotropic conductor is accommodated inside, an electrically conductive reinforcing material is laminated on the outer circumferential surface of the container, and the wall thickness of the container formed of the electrically anisotropic conductor is accurately measured.

In addition, the present invention has an effect of increasing measurement accuracy by allowing the sensing coil to sense only the secondary magnetic field applied by the eddy current formed in the electric isotropic conductor accommodated inside the container and not to sense the primary magnetic field applied by the excitation coil.

In addition, the present invention has the effect of allowing the primary magnetic field formed by the excitation coil to pass through the container wall, which is an anisotropic conductor.

In addition, the present invention has an effect of reducing measurement noise due to the electrically conductive reinforcing material by inserting an electromagnetic wave blocking member between the non-conductive medium and the electrically conductive reinforcing material.

In addition to the effects described above, specific effects of the present invention will be described together while explaining specific details for carrying out the present invention.

1 is a cross-sectional view of a container in which an electrically conductive reinforcing material according to the present invention is laminated.
2 is a perspective view showing a portion of a container wall in which an electrically conductive reinforcing material according to the present invention is laminated.
3 is a view explaining the anisotropy of the container wall according to the present invention.
4 is a diagram explaining a situation in which eddy currents are formed by a magnetic field generated from a coil to which current is applied.
5 is a diagram explaining the penetration depth of a magnetic field.
6 is a diagram illustrating a real part and an imaginary part of a sensing coil voltage signal by a secondary magnetic field.
7 is a block diagram of an apparatus for measuring the thickness of a container wall according to a first embodiment of the present invention.
8 is a diagram showing an excitation coil according to a first embodiment of the present invention.
9 is a diagram showing a sensing coil according to a first embodiment of the present invention.
10 is a diagram illustrating eddy currents and a primary magnetic field formed by applying a current to an excitation coil according to the present invention.
11 is a diagram showing a secondary magnetic field formed by applying a current to an excitation coil according to the first embodiment of the present invention.
12 is a block diagram of a device for measuring the thickness of a container wall according to a second embodiment of the present invention.
13 is a diagram showing a secondary magnetic field formed by applying a current to an excitation coil according to a second embodiment of the present invention.

Hereinafter, preferred embodiments will be described in detail so that those skilled in the art can easily practice the present invention with reference to the accompanying drawings. Hereinafter, various embodiments of this document will be described with reference to the accompanying drawings. However, this is not intended to limit the technology described in this document to specific embodiments, and is to be understood as including various modifications, equivalents, and/or alternatives of the embodiments of this document. In connection with the description of the drawings, like reference numerals may be used for like elements.

In addition, expressions such as “first,” “second,” etc. used in this document may modify various components regardless of order and/or importance, and to distinguish one component from another. It is used only and does not limit the corresponding components. For example, 'first part' and 'second part' may indicate different parts regardless of order or importance. For example, without departing from the scope of rights described in this document, a first element may be called a second element, and similarly, the second element may also be renamed to the first element.

In addition, terms used in this document are only used to describe a specific embodiment, and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by a person of ordinary skill in the technical field described in this document. Among the terms used in this document, terms defined in a general dictionary may be interpreted as having the same or similar meaning as the meaning in the context of the related art, and unless explicitly defined in this document, an ideal or excessively formal meaning. not be interpreted as In some cases, even terms defined in this document cannot be interpreted to exclude the embodiments of this document.

1 is a cross-sectional view of a container in which an electrically conductive reinforcing material according to the present invention is laminated, FIG. 2 is a perspective view showing a portion of a container wall in which an electrically conductive reinforcing material according to the present invention is laminated, and FIG. 3 is a container wall according to the present invention. It is a diagram explaining the anisotropy of

Description will be made with reference to FIGS. 1 to 3 .

In the container according to the present invention, an isotropic conductor 30 is accommodated therein

The shape of the vessel may be cylindrical like a general pressure vessel or may be a rectangular parallelepiped with a space formed therein. That is, the shape of the container can be transformed into various forms with an accommodation space formed therein.

The container wall 20 is formed of an electrically anisotropic conductor. Electrical anisotropy refers to the property that the electrical conductivity varies depending on the direction.

Prior to explaining the electrical anisotropy of the container wall 20, first, the thickness direction of the container wall 20 is defined as a horizontal direction.

As shown in FIG. 3, the electrical conductivity of the container wall 20 has a maximum value in the vertical and horizontal directions, and a minimum value in the circumferential direction of the wall 20, which is a direction perpendicular to the vertical and horizontal directions. do.

If the electrical conductivity is high, current flows well, so that the container wall 20 flows well in the vertical and horizontal directions. That is, in the coordinate system shown in FIG. 3, current flows well in the y-axis and z-axis directions, that is, on the yz plane, but does not flow well in the x-axis direction.

FIG. 4 is a diagram illustrating a situation in which eddy currents are formed by a magnetic field generated from a coil 40 to which a current is applied.

This will be described with reference to FIG. 4 .

When a current density J flows through a magnetic coil, a magnetic field (B) as shown in FIG. 4 is formed around the coil 40. At this time, the relationship between the current density and the magnetic field can be expressed by the following equation.

(One)

where μ is It refers to magnetic permeability ( μ ).

When the magnetic field changes with time, an electric field (E) is induced by the following equation.

(2)

When an electric field is applied to a conductive medium, an eddy current (j) flows according to the following equation. At this time, the density of the eddy current is proportional to the magnitude of the electric field and the magnitude of the electric conductivity ( σ ).

(3)

Therefore, an eddy current in the form of a red arrow in FIG. 4 flows in the conductor. At this time, if the magnetic field applied from the outside is an alternating current, the eddy current also becomes an alternating current, and the direction is reversed with time.

Just as a current (J) flowing in a magnetic coil induces a primary magnetic field (B), an eddy current (j) flowing in a conductor induces a secondary magnetic field (b). This can be written in the form of Equation (1) as follows.

(4)

As in Equation (2), when the primary and secondary magnetic fields 80 and 90 change with time, an electric field is induced as follows.

(5)

In general, the magnitude of the magnetic field of secondary induction is very small compared to that of primary induction.

When the electric field formed by the first and second induction is applied to the coil 40, a voltage V corresponding to the magnitude of the integral of the tangential line of the induced electric field is applied to the coil 40 as follows.

(6)

The magnetic field is not always able to penetrate inside the medium as shown in FIG. 4 . If the electrical conductivity of the medium is high or the magnetic permeability ( μ ) is high, the secondary magnetic field induced by the eddy current cancels the primary magnetic field, and as a result, the magnetic field from the magnetic coil does not penetrate the medium and appears to be reflected. . The depth at which a magnetic field (or electric field) can penetrate a conductive medium (usually a conductor) is called the penetration depth ( δ _p ), which is defined as: Here, f is the frequency of the applied alternating magnetic field, σ is the electrical conductivity, and μ is the magnetic permeability.

(7)

As shown in Equation (7), the penetration depth becomes shallower as the excitation frequency is higher and the electrical conductivity and magnetic permeability are higher. Figure 5 (a) and (b) show the magnetic field when the penetration depth is deep and shallow, respectively. When the penetration depth is deeper than the thickness ( L ) of the medium by changing the excitation frequency for a medium with the same electrical conductivity and magnetic permeability (Fig. 5(a)), the magnetic field freely penetrates the medium, but when the penetration depth is shallower than the medium 5(b)) The magnetic field does not penetrate the medium and is reflected.

)Since the electric and magnetic fields, which are alternating vectors, have phases, they can be expressed as complex numbers in the frequency domain through Fourier transformation (

)

로 치환되는데, 여기서,

는 단위허수, ω는 각속도를 의미한다.The Fourier transform of Equation (5) gives: In this case, the time differential is

is replaced by, where,

is the unit imaginary number, and ω means the angular velocity.

(8)

Here, the primary magnetic field (B) and the secondary magnetic field (b) are induced by excitation current (J) and eddy current (j), respectively, as follows.

(9)

(10)

Similarly, equations (3) and (6) are Fourier transformed as follows.

(11)

(12)

는 다음과 같이 실수부와 허수부로 분리할 수 있으며, Coil voltage in equation (12)

can be separated into real and imaginary parts as follows,

(13)

If this is expressed in the time domain, it is divided into a cosine function and a sine function having a phase difference of 90 degrees between each other as follows.

(14)

)는 가진전류(

)에 대해 iω의 관계를 갖는다. 따라서 90도의 위상차를 갖는 허수부가 된다. 반면에 (12), (8), (10), (11), (9)에서 코일전압과 가진전류는 의 제곱 혹은 그 이상의 관계를 갖게 되고 따라서 실수부 성분을 포함하게 된다.Combining Equations (12), (8), and (9), the coil voltage (

) is the excitation current (

) has a relation of iω to Therefore, it becomes an imaginary part having a phase difference of 90 degrees. On the other hand, in (12), (8), (10), (11), and (9), the coil voltage and the excitation current have a square or higher relationship of , and thus include real component components.

In FIG. 4, the secondary magnetic field 90 due to the eddy current induced inside the conductor accommodated in the container can be detected as a component of the real part of the coil voltage.

The problem is that since the secondary magnetic field 90 is much smaller than the primary magnetic field 80, the detected real component is much smaller than the imaginary component.

6 shows a coil voltage signal when the real part is smaller than the imaginary part by about 1/5. The voltage signal obtained by combining the real part and the imaginary part has a slightly larger amplitude and a slightly faster phase than the imaginary part.

Since only minute real part components need to be separated from these signals, if the difference between the real part and the imaginary part is more than 100 times, it becomes very difficult to accurately separate the real part signal from the actual measured signal.

If the container wall 20 is made of an insulating material, the wall thickness can be measured using an electromagnetic field in an ideal situation as shown in FIG. 4 . This is because the insulating material appears transparent to the electromagnetic field.

However, if the container wall 20 is a conductor, it appears opaque to the electromagnetic field. Therefore, a penetration depth sufficient to penetrate the container wall 20 must be secured so that the electromagnetic field can penetrate the conductor inside, and the effect of eddy currents induced in the container wall 20 must also be considered.

The container wall 20 according to the present invention is formed of an electrically anisotropic material whose electrical conductivity varies depending on the direction. Accordingly, since the eddy current flowing through the container wall 20 is also affected by the electrical anisotropy, when designing the applying coil and the sensing coil 70, the effect of the electrical anisotropy of the container wall 20 should be minimized.

7 is a block diagram of a device for measuring the thickness of a container wall according to a first embodiment of the present invention, FIG. 8 is a diagram showing an excitation coil according to the first embodiment of the present invention, and FIG. 9 is a view showing the first embodiment of the present invention. 10 is a diagram showing a sensing coil according to the first embodiment, and FIG. 10 is a diagram showing eddy currents 50 and a primary magnetic field formed by applying current to the excitation coil according to the first embodiment of the present invention. 11 is a diagram showing a secondary magnetic field 90 formed by applying a current to the excitation coil according to the first embodiment of the present invention.

An apparatus for measuring the thickness of the container wall 20 according to the first embodiment of the present invention will be described with reference to FIGS. 7 to 11 .

An apparatus for measuring container wall thickness according to the present invention includes a current supply unit 100, an excitation coil 60, a sensing coil 70, a voltage measurement unit 200, and a control unit 300.

The current supply unit 100 is configured to supply the coil 60 with alternating current.

The excitation coil 60 is mounted between the container wall 20 and the electrically conductive reinforcing material 32. A primary magnetic field 80 is formed in the excitation coil 60 by the alternating current applied by the current supply unit 100 .

The excitation coil 60 is disposed between the container wall 20 and the electrically conductive reinforcing material 32 in a state of being embedded in the non-conductive medium 34 together with the sensing coil 70 to be described later.

The excitation coil 60 is wound so that the winding axis direction is horizontal on the xy plane, that is, toward the z-axis direction, as shown in FIG. 8 so that the primary magnetic field 80 passes through the container wall 20 well. This is because the container wall 20 having electric anisotropy allows current to flow well on the yz plane and also transmits a magnetic field well.

Eddy current 50 is formed adjacent to the interface between the electrical isotropic conductor 30 accommodated inside the container and the container wall 20 by the primary magnetic field 80 .

These eddy currents 50 cause a secondary magnetic field 90 to be formed.

The sensing coil 70 is mounted spaced apart from the excitation coil 60 at a predetermined interval between the container wall 20 and the electrically conductive reinforcing material 32 .

The voltage measurement unit 200 measures the voltage applied to the sensing coil 70 and transmits it to the control unit 300 .

The current flowing in the excitation coil 60 forms a primary magnetic field 80 in the yz plane where electricity flows well in the container wall 20, and the primary magnetic field 80 accommodates the electric isotropic conductor 30 inside the container ) and the container wall 20, eddy currents are generated in the xy plane. The eddy current induces a secondary magnetic field 90 in the yz plane towards the container wall 20.

In the thickness measuring device according to the present invention, the thickness of the container wall 20 is measured by measuring the voltage applied to the sensing coil 70 by the secondary magnetic field 90 .

In the present invention, in order to prevent the magnetic field from being formed in the xz plane on the container wall 20, the excitation coil 60 has a rectangular cross-section. In the cross-sectional shape of the excitation coil 60, the long portion faces the circumferential direction of the wall 20, that is, the x-direction, and the short-length portion faces the y-direction.

10 shows a primary magnetic field 80, and FIG. 11 shows a secondary magnetic field 90.

The control unit 300 controls the overall operation of the wall thickness measurement device, and calculates the thickness of the container wall 20 from the voltage received from the voltage measurement unit 200.

That is, the wall thickness is calculated from the correlation between the voltage and the container wall thickness.

Therefore, in order to accurately measure the thickness of the container wall 20, the primary magnetic field 80 must be designed so that only the secondary magnetic field 90 is transmitted without passing through the sensing coil 70.

Therefore, in the present invention, as shown in FIG. 11, the sensing coil 70 is disposed on the xz plane, and the winding axis direction is directed in the vertical direction, that is, in the y-axis direction.

Due to this, the sensing coil 70 can exclude the influence of the primary magnetic field 80 .

Also, the cross-sectional shape of the sensing coil 70 is formed in the same rectangular shape as that of the excitation coil 60. The long direction was arranged in the circumferential direction of the wall (20). In the cross-sectional shape of the sensing coil 70, the long portion faces the circumferential direction of the wall 20, that is, the x-direction, and the short-length portion faces the y-direction.

In this way, by forming a short portion of the cross-sectional shape of the sensing coil 70 toward the y-axis direction, the magnetic field in the x-axis direction is not sensed.

Since the container wall 20 does not conduct current well in the xz plane, but a small current can flow, the magnetic field in the x-axis direction formed thereby forms an eddy current, resulting in a secondary magnetic field 90 in the x-axis direction. will form Therefore, in the present invention, the short part of the sensing coil 70 is formed to face the y-axis direction, and the direction of the winding shaft is directed to the y-axis so that the magnetic field in the x-axis direction is not measured to increase measurement accuracy.

12 is a block diagram of a device for measuring the thickness of the container wall 20 according to the second embodiment of the present invention, and FIG. 13 is formed by applying a current to the excitation coil 60 according to the second embodiment of the present invention It is a diagram showing the secondary magnetic field 90.

A second embodiment will be described with reference to FIGS. 12 and 13 .

In the second embodiment according to the present invention, the first sensing coil 72 and the second sensing coil 74 are symmetrically disposed at the same distance from the coil 60 on the upper and lower portions of the coil 60, respectively. .

Since the secondary magnetic field 90 is symmetrically directed to the top and bottom of the excitation coil 60, two sensing coils 72 and 74 are disposed.

In the present invention, the first sensing coil 72 and the second sensing coil 74 are disposed symmetrically, but wound in opposite directions to each other so that common-mode magnetic noise entering the two coils is offset.

As shown in FIG. 2 , an electrically conductive reinforcing material 32 is laminated on the outer circumferential surface of the container wall 20 .

The reinforcing material not only serves to reinforce the container wall 20 in terms of strength, but also serves to cool the conductor 30 accommodated therein at a high temperature through heat conduction.

An eddy current may be formed by the primary magnetic field 80 formed by the excitation coil 60 in the electrically conductive reinforcing material 32 mounted adjacent to the container wall 20 for the purpose of reinforcing strength.

The container wall thickness measuring device according to the present invention applies an alternating current to the excitation coil 60 to measure the secondary magnetic field 90 by the eddy current formed in the electric isotropic conductor 30 accommodated inside the container to the sensing coil ( 70) to measure the thickness of the container wall 20.

However, when an alternating current is applied to the excitation coil 60, an eddy current is formed not only in the electrical isotropic conductor 30 accommodated inside the container but also in the electrically conductive reinforcing material 32 laminated on the outer circumferential surface of the container wall. Therefore, the resulting secondary magnetic field 90 is also sensed by the sensing coil 70, so it is difficult to accurately calculate the thickness of the container wall 20.

Therefore, in the present invention, the electromagnetic wave blocking member 36 is inserted between the non-conductive medium 34 in which the excitation coil 60 and the sensing coil 70 are embedded and the conductive reinforcing material 32.

As a result, the primary magnetic field 80 formed by the excitation coil 60 prevents eddy currents from being formed in the conductive reinforcing material 32, so that the sensing coil 70 has a secondary due to the conductive reinforcing material 32 The magnetic field 90 was not sensed.

As a material for the electromagnetic wave blocking member 36, it is preferable to adopt Permalloy alloy. However, it is not limited to this, and various materials may be used depending on the thickness and material of the container wall 20.

The present invention relates to an apparatus for measuring the thickness of a container wall in which electrically conductive reinforcing materials are laminated, and more particularly, to prevent eddy current from being formed in the electrically conductive reinforcing material by inserting an electromagnetic wave shielding member between a non-conductive medium and the electrically conductive reinforcing material. While blocking the primary magnetic field applied from the coil, the winding direction of the excitation coil is determined so that the primary magnetic field applied by the excitation coil passes through the container wall, which is an anisotropic electrical conductor, and the eddy current caused by the primary magnetic field An apparatus for measuring the thickness of a container wall capable of accurately measuring the thickness of the container wall by sensing only the secondary magnetic field applied and determining the winding direction of the sensing coil so that the primary magnetic field is not sensed.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, and is common in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Of course, various modifications are possible by those with knowledge of, and these modified embodiments should not be individually understood from the technical spirit or perspective of the present invention.

10: Courage
20: wall
30: electrical isotropic conductor
32: electrically conductive reinforcing material
34: non-conductive medium
36: electromagnetic wave blocking member
40: Coil
50: eddy current
60: exciting coil
70: sensing coil
72: first sensing coil
74: second sensing coil
80: primary magnetic field
90: secondary magnetic field
100: current supply unit
200: voltage measuring unit
300: control unit

Claims (9)

An electrically isotropic conductor 30 is accommodated inside the container, the wall 20 constituting the container is formed of an electrically anisotropic conductor, and an electrically conductive reinforcing material 32 is laminated on the outer circumferential surface of the container to a device for measuring the wall thickness of the container. in
Current supply unit 100 for supplying alternating current;
An excitation coil 60 mounted between the container wall 20 and the electrically conductive reinforcing material 32 and forming a primary magnetic field 80 by an alternating current applied by the current supply unit 100;
Eddy current 50 (Eddy current), which is spaced apart from the excitation coil 60 at a predetermined distance and formed between the container wall 20 and the electrically conductive reinforcing material 32, and is formed by the primary magnetic field 80 a sensing coil 70 for sensing the secondary magnetic field 90 applied by;
a voltage measuring unit 200 that measures the voltage applied to the sensing coil 70 and transmits the measured voltage to the control unit 300; and
A control unit 300 for calculating the thickness of the container wall 20 from the voltage received from the voltage measuring unit 200; includes,
The controller 300 calculates the thickness of the container wall 20 from the secondary magnetic field 90 by the eddy current 50 formed when the alternating current is applied. thickness measuring device.
According to claim 1,
The excitation coil 60 and the sensing coil 70 are disposed between the container wall 20 and the electrically conductive reinforcing material 32 in a state of being embedded in the non-electrically conductive medium 34, electrically conductive A device for measuring the thickness of the wall of a container with stacked reinforcing materials.
According to claim 2,
An electromagnetic wave blocking member 36 is inserted between the non-conductive medium 34 and the electrically conductive reinforcing material 32, and applied from the excitation coil 60 to prevent eddy current from forming in the electrically conductive reinforcing material 32 Characterized in that to block the primary magnetic field 80, the electrically conductive reinforcing material is laminated container wall thickness measuring device.
According to claim 3,
Characterized in that the electromagnetic wave blocking member 36 is Permalloy, the thickness measuring device of the container wall in which the electrically conductive reinforcing material is laminated.
According to claim 1,
The sensing coil (70) senses a secondary magnetic field (90) by an eddy current formed adjacent to the interface between the electrical isotropic conductor (30) accommodated inside the container and the container wall (20), electric A device for measuring the thickness of a container wall with conductive reinforcing materials laminated.
According to claim 5,
When the thickness direction of the container wall 20 is defined as the horizontal direction, the electrical conductivity of the container wall 20 is maximum in the vertical and horizontal directions, and the wall 20 is perpendicular to the vertical and horizontal directions. is the lowest in the circumferential direction of
The direction of the winding axis around which the excitation coil 60 is wound is horizontal, and the direction of the winding axis around which the sensing coil 70 is wound is upward and downward,
In the sensing coil 70, the voltage applied by the primary magnetic field 80 is not sensed, and only the voltage applied by the secondary magnetic field 90 is sensed. Wall thickness measuring device.
According to claim 6,
The cross-sectional shape of the excitation coil (60) and the sensing coil (70) is rectangular, and the longitudinal direction is the circumferential direction of the wall (20). Device.
According to claim 1,
The sensing coil 70,
It is mounted above the excitation coil 60 between the container wall 20 and the electrically conductive reinforcing material 32, and the eddy current 50 formed by the primary magnetic field 80 is applied a first sensing coil 72 for sensing the secondary magnetic field 90; and
It is mounted below the excitation coil 60 between the container wall 20 and the electrically conductive reinforcing material 32, and the eddy current 50 formed by the primary magnetic field 80 is applied A second sensing coil 74 for sensing a secondary magnetic field 90; characterized in that it comprises a thickness measuring device for a container wall in which an electrically conductive reinforcing material is laminated.
According to claim 8,
The first sensing coil (72) and the second sensing coil (74) are symmetrically arranged at the same distance from the excitation coil (60).

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