Eccentricity measuring device for radiographic inspection of circumferential welding joint of small-diameter tube

Abstract

The utility model relates to an eccentric distance measuring device for radiographic inspection of a small-diameter tube circumferential welding joint, which comprises a vertical rod and a graduated scale, a positioning groove is arranged on the side wall of the bottom of the vertical rod, the positioning groove is a U-shaped groove with a downward opening, the positioning groove extends along the radial direction of the vertical rod, and the graduated scale is arranged in the positioning groove. The graduated scale is fixedly installed in the positioning groove, and the initial scale of the graduated scale coincides with the axis of the vertical rod. When the device is used, the top end of the vertical rod is aligned with the position of a focal point d of an X-ray machine, the graduated scale is vertically placed on the ground, the eccentric distance L0 is directly measured on the ground through the graduated scale according to the calculated eccentric distance L0, the position of the weld center of the small-diameter tube is rapidly determined, and then the weld center of the small-diameter tube is aligned with the position of the eccentric distance to be placed. The small-diameter tube can be quickly and accurately positioned, the subsequent transillumination imaging quality and the detection efficiency are improved, the structure is simple and reasonable, and the operation is convenient.

Description

Technical Field

[0001] This utility model relates to the field of X-ray inspection technology, specifically to a device for measuring the eccentricity of a circumferential welded joint of a small-diameter pipe using X-ray inspection. Background Technology

[0002] Small-diameter pipe structures are widely used in the pressure vessel industry, and the internal quality of their circumferential welded joints is crucial. Radiographic testing is commonly used to assess the internal quality of these joints. The standard NB / T47013.2-2015, "Non-destructive Testing of Pressure Equipment Part 2: Radiographic Testing," specifies that small-diameter pipes refer to pipes with an outer diameter D0 ≤ 100 mm. It also stipulates that circumferential welded joints of small-diameter pipes should be radiographically inspected using a double-wall, double-image arrangement. When the wall thickness T ≤ 8 mm and the weld width g ≤ D0 / 4, an elliptical imaging method using oblique radiography should be used. During elliptical imaging, the image opening width (maximum distance between the upper and lower weld projections) should be controlled to approximately one weld width. An example of an elliptical imaging arrangement using oblique radiography is shown below. Figure 3 As shown, F is the focal length, L1 is the distance from the focal point d to the upper surface of the small-diameter tube, L2 is the distance from the upper surface of the small-diameter tube to the film, D0 is the outer diameter of the small-diameter tube, T is the wall thickness of the small-diameter tube, L0 is the eccentricity, d is the focal point of the X-ray source, b is the image aperture width, and g is the weld width. To control the image aperture width b and ensure imaging quality, it is necessary to calculate the eccentricity L0 of the X-ray machine focal point d relative to the center of the weld joint: L0 = L1 × (b + g) / L2.

[0003] In actual testing, after calculating the eccentricity L0, it is necessary to find the projection dˊ of the focal point d on the ground using methods such as plumb lines. Then, the eccentricity L0 is measured on the ground with a ruler, and the small-diameter pipe is placed at a distance of L0 from the center of the weld, from the focal projection dˊ, for radiography. This method requires various auxiliary tools, is time-consuming and labor-intensive, and the positioning of the small-diameter pipe is prone to deviation, resulting in the image opening width not meeting the standard requirements, thus affecting the image quality and producing unqualified inspection films. This necessitates re-inspection, increasing the workload of inspection personnel, reducing inspection efficiency, wasting film, and increasing inspection costs. Utility Model Content

[0004] This invention addresses existing technical problems by providing a device for measuring the eccentricity of circumferential welded joints of small-diameter pipes using X-ray inspection.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A device for measuring the eccentricity of a small-diameter pipe circumferential welded joint by X-ray inspection, comprising a vertical rod and a scale, wherein a positioning groove is provided on the bottom side wall of the vertical rod, the positioning groove is a U-shaped groove with an opening facing downward, the positioning groove extends radially along the vertical rod, and the scale is fixedly installed in the positioning groove, wherein the initial scale of the scale coincides with the axis of the vertical rod.

[0006] Based on the above technical solution, the present invention can be further improved as follows:

[0007] Preferably, the vertical rod is a telescopic rod.

[0008] Preferably, the height of the positioning groove corresponds to the height of the scale.

[0009] Preferably, the height of the positioning groove corresponds to the thickness of the scale.

[0010] Preferably, the ruler has an accuracy of 1 cm.

[0011] Preferably, the bottom of the vertical rod is a solid structure.

[0012] The beneficial effects of this utility model are as follows: When in use, align the top of the vertical rod with the focal point d of the X-ray machine, place the ruler vertically on the ground, and measure the eccentricity L0 directly on the ground using the ruler according to the calculated eccentricity L0. This quickly determines the position of the center of the weld seam of the small-diameter pipe. Then, align the center of the weld seam of the small-diameter pipe to be inspected with the eccentricity position. This achieves rapid and accurate positioning of the small-diameter pipe, improves the quality of subsequent radiographic imaging and inspection efficiency, and features a simple and reasonable structure that is easy to operate. Attached Figure Description

[0013] Figure 1 This is a front view of the measuring device of this utility model;

[0014] Figure 2 This is a side view of the measuring device of this utility model;

[0015] Figure 3 This is a schematic diagram illustrating the calculation of eccentricity in existing technologies.

[0016] The attached diagram is labeled as follows: 1. Vertical rod; 2. Ruler. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0019] like Figures 1 to 2 As shown, this utility model discloses a device for measuring the eccentricity of a circumferential welded joint of a small-diameter pipe using X-ray inspection. It includes a vertical rod 1 and a scale 2. A positioning groove, a U-shaped groove with an opening facing downwards, is provided on the bottom side wall of the vertical rod 1. The positioning groove extends radially along the vertical rod 1, and its depth is greater than or equal to the radius of the vertical rod 1. The scale 2 is fixedly installed within the positioning groove. The U-shaped groove structure ensures that the scale 2 directly contacts the ground during use, preventing tilting and facilitating observation of the measurement position, reducing measurement errors, and ensuring the accuracy of the measurement results. The initial scale of the scale 2, i.e., the "0" mark, coincides with the axis of the vertical rod 1, ensuring that the scale 2 is perpendicular to the vertical rod 1, thereby accurately measuring the eccentricity L0 and ensuring the accuracy of subsequent inspection results. The depth to which the scale 2 is inserted into the positioning groove can be determined based on the radius of the vertical rod 1, thus ensuring that the initial scale of the scale 2 coincides with the axis of the vertical rod 1 and guaranteeing the accuracy of the measurement results. Furthermore, the scale 2 can be interference-fitted into the positioning groove, or the scale 2 can be inserted into the positioning groove and then glued in place.

[0020] The vertical rod 1 is a telescopic rod, which makes the height of the vertical rod 1 adjustable, suitable for detection occasions with different focal lengths, thus improving the applicability and reducing the cost of use.

[0021] Furthermore, the bottom of the vertical rod 1 is a solid structure, which increases the stability of the vertical rod 1. The positioning groove is opened at the solid structure, which increases the accuracy and firmness of the scale 2 installation, avoids the scale 2 from shifting, ensures the accuracy of the measurement results, and ensures the quality and detection efficiency of subsequent radiographic imaging.

[0022] In this embodiment, the height of the positioning groove corresponds to the height of the scale 2. This makes the scale on the scale 2 face forward, facilitating the inspection personnel's observation of the values ​​on the scale 2 and improving ease of use.

[0023] The scale 2 has an accuracy of 1cm and multiple scales are evenly distributed along its length, making it convenient for inspectors to read the scales on the scale 2 and improving its ease of use.

[0024] In other alternative embodiments, the height of the positioning groove corresponds to the thickness of the scale 2, that is, the scale of the scale 2 faces upward, which can also achieve the function of measuring the eccentricity.

[0025] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An eccentricity measuring device for radiographic examination of a circumferential welded joint of a small diameter pipe, characterized in that, It includes a vertical rod (1) and a scale (2). The bottom side wall of the vertical rod (1) is provided with a positioning groove. The positioning groove is a U-shaped groove with an opening facing downwards. The positioning groove extends radially along the vertical rod (1). The scale (2) is fixedly installed in the positioning groove. The initial scale of the scale (2) coincides with the axis of the vertical rod (1).

2. The eccentricity measuring device for radiographic examination of girth welds of small diameter pipes according to claim 1, characterized in that, The vertical rod (1) is a telescopic rod.

3. The eccentricity measuring device for radiographic examination of girth welds of small diameter pipes according to claim 1 or 2, characterized in that, The height of the positioning groove corresponds to the height of the scale (2).

4. The eccentricity measuring device for radiographic examination of girth welds of small diameter pipes according to claim 1 or 2, characterized in that The height of the positioning groove corresponds to the thickness of the scale (2).

5. The eccentricity measuring device for radiographic inspection of girth welds of small diameter pipes according to claim 1, characterized in that, The accuracy of the ruler (2) is 1 cm.

6. The eccentricity measuring device for radiographic inspection of girth welds of small diameter pipes according to claim 1, characterized in that, The bottom of the vertical rod (1) is a solid structure.

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