JP3199417B2 - Standard specimen for non-destructive inspection of piping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a standard test piece used for nondestructive inspection of piping.

[0002]

2. Description of the Related Art As means for inspecting deterioration of various pipes,
Conventionally, a pipe nondestructive inspection method shown in FIG. 6 is known. In FIG. 6, 1 is an X-ray generator, 2 is a center indicator, 3 is a film, 4 is a pipe to be inspected, and 5 is a standard test piece.

[0003] The standard test piece 5 is a tubular member having the same material and the same shape as the pipe 4 to be inspected, and as shown in FIG.
It has an appropriate number of 1 to 54. The steps 51 to 54 have inner diameters D1 to D1.
D4 are different from each other, and the wall thicknesses d1 to d4 of the tube portion 50 are different.
Are values corresponding to the inner diameters D1 to D4. In the inspection, the same fluid as the fluid flowing inside the pipe 4 to be inspected is filled in the inside of the cylindrical portion 50 of the standard test piece 5, and the standard test piece 5 is arranged side by side with the pipe 4 to be inspected. , Both 4,
5 is irradiated with X-rays from the X-ray generator 1 almost uniformly, photographed with the film 3 arranged on the back side, and the contrast of the images of the two 4 and 5 recorded on the film 3 is compared. Since the standard test piece 5 has inner diameters D1 to D4 having different thicknesses d1 to d4, the larger the inner diameters D1 to D4 are, that is, the thicknesses d1 to d4.
The smaller the value of d4, the lower the density of the image. if,
If the inspection pipe 4 is deteriorated such as by corrosion, loss, cracks, etc., the density of the image photographed by the film 3 decreases at the deteriorated portion. Then, the reference concentration obtained by the standard test piece 5 is compared with the concentration of the pipe 4 to be inspected, and the deterioration of the pipe 4 to be inspected and the degree thereof are detected by means such as digitizing the difference between the two. be able to.

[0004]

However, the tube 5
Step 5 which becomes the reference data by shaving the inner surface of
The conventional standard test pieces having Nos. 1 to 54 have the following problems. (A) The conventional standard test piece 5 is made of a kind of material on the assumption that the pipe 4 to be inspected is made of a kind of material. However, current pipes often have a lining pipe structure made of a plurality of materials, mainly for the purpose of corrosion prevention, and are rarely made of one kind of material. For example, in a vinyl-lined steel pipe used for a water supply pipe, as shown in FIG. 8, a vinyl 41 having a thickness of about 1 mm is adhered to an inner surface of a pipe section 40 formed of a steel pipe.
A pipe having a lining pipe structure is connected to a conventional standard test piece 5
When the inspection is performed in (1), the photographing conditions are different due to the lining of the inspected tube 4 with the vinyl 41, so that an accurate inspection cannot be performed. (B) As the lining pipe structure, as shown in FIG. 8, the lining 41 is limited to only the inner surface of the pipe section 40, and the type in which the end face of the pipe section 40 is not lined is actually often used. When a valve or a joint 6 is connected to a pipe having such a lining pipe structure, a different metal potential difference exists between steel or iron appearing on the end face of the pipe having no lining and a metal material constituting the valve or the joint 6. Corrosion current flows due to an electrochemical mechanism such as that described above, and corrosion F occurs in the pipe axis direction at a joint such as the threaded portion 42 at the pipe end. The conventional standard test piece 5 cannot inspect such a portion. (C) For the reasons described above, the pipe having the lining pipe structure cannot be subjected to the nondestructive inspection using the conventional standard test piece, and the pipe must be actually cut and sampled for inspection. Was. For this reason, in water supply piping, etc.,
Every time the inspection was carried out, water cut-off, run-off of contaminated water due to water cut-off, restoration work, and expenditure for that were required. (D) Deterioration that occurs in the pipe to be inspected often occurs at one thick portion in the diametric direction as viewed in the X-ray irradiation direction, and the probability of simultaneous occurrence on both diametric directions is extremely low. However, in the conventional standard test piece 5, since the steps 51 to 54 are formed in a ring shape, the photographing conditions do not match the actual deterioration.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems and to easily follow the structure of a pipe to be inspected.
An object of the present invention is to provide a standard test piece capable of performing a nondestructive inspection with high accuracy regardless of a pipe structure of an inspection pipe.

[0006]

According to the present invention, there is provided a tubular non-destructive inspection standard test piece having a step for changing the wall thickness of a pipe, wherein the step comprises: It is characterized by being provided on the outer peripheral surface of the tube section.

[0007]

The step portion for changing the thickness of the tube portion is provided on the outer peripheral surface of the tube portion, so that the step portion can be formed at a necessary place in a necessary size. For example, it can be easily formed on a tube base thick portion or a threaded portion, or can be formed only on the outer surface on one side of the diameter of the tube. For this reason, it is possible to easily follow the structure of the pipe to be inspected, and to perform the nondestructive inspection with high accuracy regardless of the pipe structure of the inspection pipe.

Since the step portion is provided on the outer peripheral surface of the pipe portion, the inner surface of the pipe portion can have the same structure as the pipe to be inspected. It is also free to adopt a lining tube structure.
For this reason, corrosion of piping having a lining pipe structure
It becomes possible to detect by non-destructive inspection.

Since the step portion is provided on the outer peripheral surface of the tube portion, the step portion may be formed in a screw portion usually provided on one end side in the axial direction of the tube portion. For this reason, when a valve or a joint is connected to a pipe having a lining pipe structure, a test piece that can detect corrosion that progresses in the pipe axis direction at a connection portion by a nondestructive inspection can be realized.

Since the step portion is provided on the outer peripheral surface of the tube portion, the step portion is formed only on the outer surface on one side of the diameter of the tube portion, or a plurality of steps are provided at positions not overlapping in the X-ray irradiation direction. It is also possible to form a row, so that detection accuracy and detection workability can be improved.

[0011]

1 is an exploded perspective view of a standard test piece for pipe nondestructive inspection according to the present invention, and FIG. 2 is a partially enlarged sectional view of the same. The illustrated standard test piece includes a tube portion 7 and caps 8 and 9, and the tube portion 7 has a tube base thick portion 71 and screw portions 72 and 73. Step portions 711 to 744 for changing the thickness are provided on the outer peripheral surface of the tube base thick portion 71. Steps 711-7
Reference numeral 14 denotes depths h1 to h4 (see FIG. 2) and thicknesses d1 to d4.
Are provided so as to change sequentially. Step 71 shown
Four 1 to 714 are provided at intervals, but the number is arbitrary. Also, steps 711-714, 721-
The 723 is provided independently of each other in FIG. 1 and FIG. 2, but may be provided in a continuous step shape as shown in FIG. 3 and FIG.

The caps 8 and 9 are screwed to screw portions 72 and 73 provided on both sides of the tube portion 7. As described above, since the same fluid as the fluid flowing inside the pipe to be inspected is filled in the pipe 7 of the standard test piece, both ends in the axial direction of the pipe 7 are sealed with the caps 8 and 9. , Filling fluid into pipe section 7
Trapped inside.

Further, in the drawing, the screw portion 72 is provided with similar steps 721 to 723. Steps 721 to 72
3 is preferably provided in a region extending to a substantially middle portion of the length of the screw portion 72 with respect to the end face of the tube portion 7 so as to prevent leakage of the filling fluid.

In the pipe inspection, as described with reference to FIG. 6, the inside of the pipe portion 7 of the standard test piece is filled with the same fluid as the fluid flowing through the inside of the pipe to be inspected. An X-ray generator irradiates X-rays almost equally to the pipes to be inspected, and photographs are taken with a film disposed on the back side, and the density of both images recorded on the film is compared.
The standard test pieces have step portions 711 to 71 having different thicknesses d1 to d4.
4, 721 to 723, the thinner the step, the lower the density of the image appears. If deterioration, such as corrosion, loss, or cracks, has occurred in the pipe to be inspected, the density of the image photographed by the film decreases at the deteriorated portion.
Therefore, the steps 711 to 714 or 721 of the standard test piece are used.
723, and the concentration of the pipe to be inspected is compared, and the difference between the concentrations is digitized.
Deterioration of the pipe to be inspected and its degree can be detected.

Here, a step portion 711 for changing the thickness of the tube portion 7
Since 〜 714 and 721 ７ 723 are provided on the outer peripheral surface of the tube portion 7, they can be formed in necessary places in necessary sizes. For example, it can be easily formed on the tube base thick portion 71 or the threaded portion 72, or can be formed only on the outer surface on one side of the diameter of the tube. Therefore, it is possible to easily follow the structure of the pipe to be inspected, and to perform the nondestructive inspection with high accuracy regardless of the pipe structure of the pipe to be inspected.

In the embodiment in which the step portions 721 to 723 are formed in the screw portion 72, when a valve or a joint is connected to a pipe having a lining pipe structure, corrosion progressing in the pipe axis direction at the connection portion (see FIG. 8). , 721 to 723 can be detected as reference data. At this time, by forming the cap 8 with the same material, shape, and thickness as the valve and the joint, in substantially the same state as when the valve and the joint are connected,
Non-destructive testing of piping can be performed.

Moreover, the steps 711-714, 721-7
23 is provided on the outer peripheral surface of the pipe portion 7,
Can have the same structure as the pipe to be inspected. As shown in FIG. 5, a lining tube structure in which a lining 74 made of vinyl or the like is provided on the inner surface of the tube portion 7 is also free. Therefore, even when the pipe to be inspected has a lining pipe structure, nondestructive inspection can be performed.

Although not shown, steps 711-71
4 or 721 to 723 are provided in a plurality of rows at positions that do not overlap in the X-ray irradiation direction, so that X-rays can be irradiated from a plurality of directions to detect deterioration, thereby improving the detection workability.

[0019]

As described above, according to the present invention, the following effects can be obtained. (A) Since the step portion for changing the thickness of the pipe portion is provided on the outer peripheral surface of the pipe portion, it can easily follow the structure of the pipe to be inspected, and the nondestructive inspection can be performed regardless of the pipe structure of the inspection pipe. A standard test piece that can be executed with high accuracy can be provided. (B) By lining the inner surface of the pipe portion, it is possible to provide a standard test piece capable of performing nondestructive inspection even when the pipe to be inspected has a lining pipe structure. (C) A test piece capable of detecting, by a nondestructive inspection, corrosion progressing in a pipe axis direction at a connection part when a valve or a joint is connected to a pipe having a lining pipe structure by forming a stepped part in a screw part. Can be provided. (D) It is possible to improve the detection accuracy and detection workability by forming only one outer surface of the diameter of the tube or forming a plurality of rows of steps at positions that do not overlap in the X-ray irradiation direction. it can.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a standard test piece for pipe nondestructive inspection according to the present invention.

FIG. 2 is a partially enlarged sectional view of a standard test piece for pipe nondestructive inspection according to the present invention.

FIG. 3 is an exploded perspective view of another example of the standard test piece for nondestructive inspection of piping according to the present invention.

FIG. 4 is a partially enlarged cross-sectional view of another embodiment of the standard test piece for pipe nondestructive inspection according to the present invention.

FIG. 5 is a partially enlarged sectional view of still another example of the standard test piece for pipe nondestructive inspection according to the present invention.

FIG. 6 is a diagram illustrating a pipe nondestructive inspection method.

FIG. 7 is a partially enlarged cross-sectional view of a conventional standard test piece for pipe nondestructive inspection.

FIG. 8 is a cross-sectional view illustrating a structural example of a pipe to be inspected.

[Explanation of symbols]

 7 Tube part 71 Tube base thick part 72 Screw part 711-714 Step part 721-723 Step part

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01N 1/00 102 G01B 15/00 G01N 23/02

Claims (2)

(57) [Claims] 1. A standard test piece for pipe non-destructive inspection that includes a pipe part, a first cap, and a second cap and is independent of a pipe to be inspected, wherein the pipe part has at least an axial direction. It has a threaded portion on the outer peripheral surface of the tube on one end side, has a lining tube structure in which the inner surface of the tube facing the threaded portion is lined with vinyl or the like, and has a step portion on the outer peripheral surface of the threaded portion to change the wall thickness. The first cap is screwed to the screw portion to close the tube portion, and the second cap is a tube portion at a side opposite to one end of the screw portion. And a standard test piece for non-destructive inspection of pipes, the test piece being closed with the pipe section. 2. The standard test piece for pipe nondestructive inspection according to claim 1, wherein the pipe section has a pipe base thick section, and the step section is provided in the pipe base thick section.