阅读说明：本技术 铁磁性金属厚度测量装置 (Ferromagnetic metal thickness measuring device ) 是由 姜涛 张诗悦 李东升 于 2021-07-01 设计创作，主要内容包括：本发明涉及测量技术领域,尤其是一种铁磁性金属厚度测量装置,包括非磁性外壳、放大组件、磁性件、第一等截面应变件和第一光纤光栅,放大组件包括连接杆和转动杆,连接杆与转动杆构成杠杆结构,磁性件与转动杆左侧的杆身连接；第一等截面应变件的一端与转动杆右侧的杆身连接,第一等截面应变件的另一端与非磁性外壳的内壁连接,第一等截面应变件到连接支点的距离小于磁性件到连接支点的距离；第一光纤光栅沿第一等截面应变件的长度方向贴合于第一等截面应变件,用于测量第一等截面应变件的应变变化。本发明通过杠杆放大原理将磁性测量和光纤光栅应变传感结合在一起,准确地测量铁磁性金属的厚度。(The invention relates to the technical field of measurement, in particular to a ferromagnetic metal thickness measuring device which comprises a nonmagnetic shell, an amplifying assembly, a magnetic part, a first equal-section strain part and a first fiber bragg grating, wherein the amplifying assembly comprises a connecting rod and a rotating rod, the connecting rod and the rotating rod form a lever structure, and the magnetic part is connected with a rod body on the left side of the rotating rod; one end of the first equal cross-section strain piece is connected with the rod body on the right side of the rotating rod, the other end of the first equal cross-section strain piece is connected with the inner wall of the non-magnetic shell, and the distance from the first equal cross-section strain piece to the connecting fulcrum is smaller than the distance from the magnetic piece to the connecting fulcrum; the first fiber grating is attached to the first equal cross-section strain element along the length direction of the first equal cross-section strain element and used for measuring the strain change of the first equal cross-section strain element. The invention combines the magnetic measurement and the fiber bragg grating strain sensing together by the lever amplification principle, and accurately measures the thickness of the ferromagnetic metal.)

1. A ferromagnetic metal thickness measuring device, comprising:

a non-magnetic housing (100);

the amplifying assembly (200) comprises a connecting rod (201) and a rotating rod (202), one end of the connecting rod (201) is connected with the inner wall of the non-magnetic shell (100), the other end of the connecting rod (201) is rotatably connected with the rotating rod (202), and the connecting part of the connecting rod (201) and the rotating rod (202) is a connecting fulcrum;

a magnetic member (300), wherein the magnetic member (300) is connected with the shaft on the left side of the rotating rod (202);

a first uniform cross-section strain part (400), wherein one end of the first uniform cross-section strain part (400) is connected with the shaft body on the right side of the rotating rod (202), the other end of the first uniform cross-section strain part (400) is connected with the inner wall of the non-magnetic shell (100), and the distance from the first uniform cross-section strain part (400) to a connecting fulcrum is smaller than the distance from the magnetic part (300) to the connecting fulcrum;

and the first fiber grating (500), wherein the first fiber grating (500) is attached to the first equal cross-section strain element (400) along the length direction of the first equal cross-section strain element (400) and is used for measuring the strain change of the first equal cross-section strain element (400).

2. The ferromagnetic metal thickness measuring device according to claim 1, wherein the magnetic member (300) and the first constant cross-section strain member (400) are respectively connected to the ends of the rotating rod (202), and the length of the shaft from one end of the rotating rod (202) to the connecting fulcrum is not equal to the length of the shaft from the other end of the rotating rod to the connecting fulcrum.

3. The device for measuring ferromagnetic metal thickness according to claim 1, wherein the first fiber grating (500) is attached to the first constant cross-sectional strain element (400) along a length direction of the first constant cross-sectional strain element (400).

4. The ferromagnetic metal thickness measuring device of claim 1, further comprising a second bisector strain element (600) and a second fiber grating (700);

one end of the second equal-section strain element (600) is connected with the inner wall of the non-magnetic shell (100), and the second fiber bragg grating (700) is attached to the second equal-section strain element (600) along the length direction of the second equal-section strain element (600) and used for measuring the strain change of the second equal-section strain element (600).

5. The ferromagnetic metal thickness measuring device according to claim 4, wherein the second fiber grating (700) is attached to a center position of the second equi-section strain element (600), and a base material of the first equi-section strain element (400) is the same as a base material of the second equi-section strain element (600).

6. The ferromagnetic metal thickness measuring device of claim 1, wherein the magnetic member (300) is a strong magnet.

7. The ferromagnetic metal thickness measuring device of claim 1, wherein the non-magnetic housing (100) is made of an aluminum alloy material.

8. The ferromagnetic metal thickness measuring device according to any one of claims 1 to 7, wherein the magnetic member (300) is connected to an upper surface or a lower surface of a shaft on a left side of the rotating rod (202), and the first constant cross-sectional strain member (400) is connected to an upper surface or a lower surface of a shaft on a right side of the rotating rod (202).

Technical Field

The invention relates to the technical field of pipeline measurement, in particular to a ferromagnetic metal thickness measuring device.

Background

Steel is the most widely used material, especially in the building and pipeline transportation industries. The thickness of steel is one of the characteristic parameters of the structure size, and is mostly related to the service state and the bearing capacity of the structure. During the use process, the steel is also extremely easy to corrode, and the corrosion effect is mainly reflected in the influence on the thickness. Under certain conditions, the acting force between the strong magnet and the ferromagnetic metal has a direct relation with the thickness, so the thickness of the ferromagnetic metal can be measured by measuring the magnetic attraction between the strong magnet and the ferromagnetic metal such as steel. The grating fiber is a novel sensor with high measurement accuracy, strong anti-interference capability and corrosion resistance, and is widely applied to various actual projects. The invention utilizes the magnetic attraction effect and combines the fiber bragg grating sensor, can convert the wall thickness information of ferromagnetic metal into the wavelength change value of the fiber bragg grating, develops the ferromagnetic metal thickness measuring sensor which has high sensitivity, simple form, easy processing and convenient engineering application, and can be applied to the field of wall thickness monitoring of long-distance oil and gas pipelines and the like.

Disclosure of Invention

The present invention is directed to a ferromagnetic metal thickness measuring device, which solves one or more of the problems of the prior art, and provides at least one of the advantages of the present invention.

A ferromagnetic metal thickness measurement device, comprising:

a non-magnetic housing;

the amplifying assembly comprises a connecting rod and a rotating rod, one end of the connecting rod is connected with the inner wall of the non-magnetic shell, the other end of the connecting rod is rotatably connected with the rotating rod, and a connecting fulcrum is arranged at the joint of the connecting rod and the rotating rod;

the magnetic part is connected with the rod body on the left side of the rotating rod;

one end of the first equal cross-section strain piece is connected with the rod body on the right side of the rotating rod, the other end of the first equal cross-section strain piece is connected with the inner wall of the non-magnetic shell, and the distance from the first equal cross-section strain piece to the connecting fulcrum is smaller than the distance from the magnetic piece to the connecting fulcrum;

the first fiber grating is attached to the first equal cross-section strain piece along the length direction of the first equal cross-section strain piece and used for measuring the strain change of the first equal cross-section strain piece.

Further, the magnetic part and the first constant cross section strain part are respectively connected with the tail end of the rotating rod, and the length of the rod body from one end of the rotating rod to the connecting fulcrum is not equal to the length of the rod body from the other end of the rotating rod to the connecting fulcrum.

Further, the first fiber grating is attached to the first constant cross-section strain member along the length direction of the first constant cross-section strain member.

Further, the fiber bragg grating device also comprises a second equal-section strain element and a second fiber bragg grating;

one end of the second equal-section strain element is connected with the inner wall of the non-magnetic shell, and the second fiber bragg grating is attached to the second equal-section strain element along the length direction of the second equal-section strain element and used for measuring the strain change of the second equal-section strain element.

Furthermore, the second fiber bragg grating is attached to the center of the second equal-section strain element, and the base material of the first equal-section strain element is the same as that of the second equal-section strain element.

Further, the magnetic member is a strong magnet.

Further, the nonmagnetic shell is made of an aluminum alloy material.

Further, the magnetic member is connected to the upper surface or the lower surface of the shaft body on the left side of the rotating lever, and the first constant cross-section strain member is connected to the upper surface or the lower surface of the shaft body on the right side of the rotating lever.

The invention has the beneficial effects that: the lever principle is used for combining magnetic measurement and fiber bragg grating strain sensing together, the acting force between the strong magnet and the ferromagnetic metal is amplified, the thickness of the ferromagnetic metal is accurately measured, and the lever type ferromagnetic metal strain gauge has the advantages of being simple in measuring method, free of damage to the structure, corrosion-resistant, low in cost, high in precision and the like.

Drawings

Fig. 1 is a schematic plan view of a ferromagnetic metal thickness measuring device according to an embodiment.

Fig. 2 is a schematic plan view of another ferromagnetic metal thickness measuring apparatus according to an embodiment.

Fig. 3 is a schematic plan view of a ferromagnetic metal thickness measuring apparatus according to a second embodiment.

Fig. 4 is a schematic plan view of a ferromagnetic metal thickness measuring apparatus according to a third embodiment.

Fig. 5 is a schematic plan view of another ferromagnetic metal thickness measuring apparatus according to the third embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the present invention will be further described with reference to the embodiments and the accompanying drawings.

Example one

Referring to fig. 1 and 2, the ferromagnetic metal thickness measuring apparatus includes a non-magnetic housing 100, and an amplifying assembly 200 as a detecting device, a magnetic member 300, a first equal cross-section strain member 400, and a first fiber grating 500.

The non-magnetic shell 100 is used to enclose the detection device inside, protect the detection device inside, prevent external factors from affecting the detection precision, and prevent the detection device inside the non-magnetic shell 100 from being contaminated by the contents in the pipeline, in this embodiment, the non-magnetic shell 100 is made of an aluminum alloy material, and the non-magnetic shell 100 has good rigidity.

The amplifying assembly 200 comprises a connecting rod 201 and a rotating rod 202, one end of the connecting rod 201 is connected with the inner wall of the non-magnetic shell 100, the other end of the connecting rod 201 is rotatably connected with the rotating rod 202, the connecting rod 201 is perpendicular to the inner wall of the non-magnetic shell 100, and the connecting part of the connecting rod 201 and the rotating rod 202 is a connecting fulcrum.

The left side and the right side of the connection fulcrum are respectively the shaft body of the rotation rod 202, wherein the magnetic member 300 is connected with the shaft body on the left side of the rotation rod 202, one end of the first equal cross-section strain member 400 is connected with the shaft body on the right side of the rotation rod 202, the other end of the first equal cross-section strain member 400 is further connected with the inner wall of the non-magnetic shell 100, the first equal cross-section strain member 400 is perpendicular to the inner wall of the non-magnetic shell 100, and the distance from the first equal cross-section strain member 400 to the connection fulcrum is less than the distance from the magnetic member 300 to the connection fulcrum.

In this embodiment, the magnetic member 300 is a ferromagnetic body, and the size of the magnetic member 300 is larger than the thickness of the ferromagnetic metal to be measured.

The first fiber grating 500 is used for detecting the strain amount of the first equi-section strain element 400, and is attached to the first equi-section strain element 400 along the length direction of the first equi-section strain element 400, and when the first equi-section strain element 400 is stressed to generate strain, the first fiber grating 500 may generate strain accordingly.

In this embodiment, the magnetic member 300 and the first constant cross-section strain member 400 may be both located on the upper side of the rotating rod 202, or may be both located on the lower side of the rotating rod 202.

The ferromagnetic metal thickness measuring device provided by the embodiment combines magnetism measurement and fiber grating strain sensing together through the lever amplification principle, the magnetic part 300 is attracted with the ferromagnetic metal to be detected, so that the magnetic part 300 has a tendency to be close to the ferromagnetic metal, the distance between the magnetic part 300 and the ferromagnetic metal is constant, the pulling force generated by magnetic attraction acts on the first equal-cross-section strain part 400 after being amplified in proportion through the rotating rod 202, the first equal-cross-section strain part 400 has good linear elastic deformation capability and meets the small deformation condition, when the strain occurs in the elastic range of the first equal-cross-section strain part 400, the first fiber grating 500 deforms in a coordinated manner, the central wavelength of the first fiber grating 500 is demodulated through the fiber grating demodulator, and the measurement of the ferromagnetic metal thickness is realized.

The specific measurement calculation process is as follows:

the relationship between the force applied to the first constant cross-section strain element 400 and the tensile force applied to the magnetic element 300 is determined according to the following formula (1):

F₁·L₁＝F₂·L₂ (1)

wherein, F₁Indicating a pulling force, L, applied by the magnetic member 300 to the left side of the rotating lever 202₁Indicates the shaft length from the magnetic member 300 to the connection fulcrum, F₂Showing the tensile force, L, experienced by the first constant cross-section strain gauge 400 on the right side of the rotating rod 202₂The shaft length from the first constant section strain element 400 to the connection fulcrum is shown.

The relationship between the axial strain of the first equal section strain element 400 and the tensile force of the magnetic element 300 is determined according to the following formula (2):

where ε is the axial strain amount of the first equal section strain gauge 400, and A, E is the cross-sectional area and the modulus of elasticity of the first equal section strain gauge 400, respectively.

The relationship between the amount of change of the center wavelength of the first fiber grating 500 and the axial strain of the first equal cross-section strain element 400 is determined according to the following formula (3):

Δλ₁＝α₁ε+α₂ΔT (3)

wherein, Δ λ₁Is the central wavelength variation, alpha, of the first fiber grating 500₁Is the strain sensitive coefficient, α, of the first fiber grating 500₂Is the temperature sensitivity coefficient of the first fiber grating 500, and Δ T is the current temperature value.

Because the pulling force that the magnetic part 300 applyed to the dwang 202 left side is positive correlation with ferromagnetic metal thickness, and that is the thickness is bigger, the pulling force that the magnetic part 300 applyed to the dwang 202 left side is bigger, on the contrary, the pulling force that the magnetic part 300 applyed to the dwang 202 left side is smaller to whether the central wavelength variation according to first fiber grating 500 determines ferromagnetic metal thickness to be in reasonable state.

The magnetic member 300 and the first equal cross-section strain member 400 described in this embodiment are respectively connected to the end of the rotation rod 202, and the length of the shaft from one end of the rotation rod 202 to the connection fulcrum is not equal to the length of the shaft from the other end of the rotation rod 202 to the connection fulcrum, so that the length of the shaft on the left side of the rotation rod 202 is greater than the length of the shaft on the right side of the rotation rod 202.

The first fiber grating 500 of this embodiment is attached to the center of the first constant cross-section strain element 400.

Example two

Referring to fig. 3, on the basis of the first embodiment, the ferromagnetic metal thickness measuring apparatus provided in the present embodiment further includes a second equal-section strain element 600 and a second fiber grating 700.

Specifically, one end of the second equal-section strain element 600 is connected with the inner wall of the non-magnetic shell 100, and the second fiber grating 700 is attached to the second equal-section strain element 600 along the length direction of the second equal-section strain element 600 and used for measuring the strain change of the second equal-section strain element 600; the second fiber grating 700 is attached to the center of the second equi-section strain element 600, and the base material of the first equi-section strain element 400 is the same as the base material of the second equi-section strain element 600.

The second equal section strain element 600 and the second fiber grating 700 are used for measuring real-time temperature, and specifically, the relationship between the central wavelength variation of the second fiber grating 700 and the axial strain of the second equal section strain element 600 is determined according to the following formula (4):

Δλ₂＝α₃ΔT (4)

wherein, Δ λ₂Is the central wavelength variation, alpha, of the second fiber grating 700₃Is the temperature sensitivity coefficient of the second fiber grating 700.

When the same type of fiber gratings are used as the first fiber grating 500 and the second fiber grating 700, the temperature sensitivity coefficient α of the first fiber grating 500 is larger₂Temperature sensitivity coefficient alpha of the second fiber grating 700₃Similarly, from the formula (3) and the formula (4), the following formula (5) can be obtained:

Δλ₁＝α₁ε+Δλ₂ (5)

the second equal-section strain element 600 and the second fiber bragg grating 700 which are specially used for detecting temperature are arranged, because the second equal-section strain element 600 is not under the action of tensile force, the strain generated by the temperature is more accurate, and the first equal-section strain element 400 and the second equal-section strain element 600 are measured in a combined mode and have higher precision.

EXAMPLE III

Referring to fig. 4 and 5, the ferromagnetic metal thickness measuring apparatus of the present embodiment provides another mounting structure of the magnetic element 300 and the first constant cross-section strain element 400 based on the first embodiment.

Specifically, it may be that the magnetic member 300 is on the upper side of the rotating rod 202 and the first equal sectional strain gauge 400 is on the lower side of the rotating rod 202, or that the magnetic member 300 is on the lower side of the rotating rod 202 and the first equal sectional strain gauge 400 is on the upper side of the rotating rod 202.

In this embodiment, when the thickness of the ferromagnetic metal is reduced, the magnetic attraction between the magnetic member 300 and the ferromagnetic metal is weakened, the pulling force finally applied to the first constant cross-section strain member 400 by the magnetic member 300 via the rotating rod 202 is reduced, the axial strain of the first constant cross-section strain member 400 is reduced, and the thickness of the ferromagnetic metal is determined according to the variation of the central wavelength of the first fiber grating 500.

As used herein, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.