CN103439157A - Test block for digital radiographic detection of disc insulator point defects and manufacturing method of test block - Google Patents

Abstract

The invention discloses a digital ray detection test block for point-like defects of pot-type insulators and a manufacturing method thereof. Stepped block structure, the height of the upper surface of the three steps from bottom to top is between 25mm-35mm, 55mm-65mm, 85mm-95mm respectively, and the upper surface of each step is provided with multiple flat-bottomed holes with different apertures. The present invention utilizes the differences in radiation absorbed doses of flat-bottomed holes arranged at different depths on the stepped surface, and by observing the minimum detectable apertures of point-like defects of basin-type insulators with different thicknesses at different distances from the detection site to the imaging plate, it is determined that the detection system can The smallest point defect detected, so as to conveniently and intuitively judge the detection sensitivity of point defect of the digital ray inspection system.

Description

A digital ray detection test block for point-like defects of pot-type insulators and its manufacturing method

technical field

The invention relates to a digital ray detection device for point defects of basin-type insulators, in particular to a digital ray detection test block for point defects of GIS basin-type insulators and a manufacturing method thereof.

Background technique

The full name of GIS in Chinese is metal-insulated metal-enclosed switch, which is the core component of modern power grid. GIS components are composed of central conductors, operating parts, shells and pot insulators, and the internal space is filled with sulfur hexafluoride insulating gas. The pot insulator is made of composite material, which is mechanically mixed and stirred by epoxy resin and alumina powder, and then vacuum cast in a metal mold. The pot insulator has a pot structure, the upper center is inlaid with a cylindrical center conductor, and the protruding part of the lower pot is the connecting part of the pot insulator and the GIS cylinder. The thickness of pot insulators for 1000KV lines is generally between 60mm-90mm, and the pot height is between 300mm-400mm; the thickness of 500KV pot insulators is generally between 40mm-70mm, and the pot height is between 250mm-350mm; the thickness of pot insulators below 500KV Generally between 25mm-40mm, the pot height is between 200mm-300mm. Basin insulators are made by vacuum casting after mixing epoxy resin and alumina powder. The main defects are cracks, pores, inclusions, stress damage caused by uneven density of the insulating pot, and poor bonding between the central columnar conductor and the insulating pot. Among them, defects such as pores and point inclusions are point defects. Since the basin insulator needs to withstand the stress caused by gas pressure, temperature change and impact force generated by mechanical operation during operation, the above defects may cause the discharge breakdown of the basin insulator during operation, resulting in the outage of the entire line. In particular, due to the large number of point defects such as pores, it is difficult to control the process. The gas gap formed by the point defects will cause high-voltage discharge, and the heat generated by the discharge will cause carbonization of the pot insulator, resulting in failure of the overall insulation of the equipment. , causing serious production accidents.

In order to avoid production accidents caused by point defects of pot insulators, the quality of pot insulators needs to be tested during the production process of pot insulators. The commonly used quality inspection method for pot insulators is the digital ray inspection method. In the digital radiography method, there are three parameters for judging the sensitivity of digital radiography, which are spatial resolution, pixel resolution and density resolution. Spatial resolution is the minimum limit of the geometric size (tiny details) of adjacent areas that can be recognized in digital images, that is, the ability to resolve image details. A pixel is the smallest unit in digital imaging of a flat panel detector. Density resolution is the minimum limit of the density (or gray level) difference between adjacent areas in the field of view of the image that can be recognized in the image, that is, the resolution ability of subtle density (gray level) differences. Density resolution and spatial resolution are two aspects of resolution indicators. Resolution is also called resolution, which is the ability to distinguish two adjacent images or images when imaging the imaging medium. These three aspects jointly affect the sensitivity of digital ray detection of point defects of pot insulators. In actual production, it is necessary to test the sensitivity of digital ray detection of point defects of pot insulators to verify the reliability of point defect detection of digital ray detection system.

Contents of the invention

The purpose of the present invention is to provide a digital ray detection test block for point defects of pot insulators and its manufacturing method, which can test the minimum detectable apertures of point defects of different thicknesses of pot insulators at different distances from the detection site to the imaging plate, It can conveniently and intuitively judge the detection sensitivity of the point defect of the digital ray detection system.

The present invention adopts following technical scheme:

A digital ray detection test block for point-like defects of pot-type insulators. The digital ray-ray detection test block for point-like defects of pot-type insulators is a three-step block structure made of a mixture of epoxy resin and alumina powder materials. The heights of the upper surfaces of the top three steps are respectively between 25mm-35mm, 55mm-65mm, and 85mm-95mm, and the upper surface of each step is provided with a plurality of flat-bottomed holes with different apertures.

The centers of the flat-bottomed holes are located on the transverse centerline of the stepped surface, and the distance between two adjacent flat-bottomed holes is 10 mm.

The upper surface of each step is provided with 6 flat-bottomed holes, the depth of each flat-bottomed hole is the same as the hole diameter, and the hole diameters of the 6 flat-bottomed holes are 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm respectively.

The upper surface heights of the three steps from bottom to top are 30mm, 60mm and 90mm respectively.

The widths of the three steps are all 40mm, and the lengths are all 100mm.

A method for manufacturing a digital ray detection test block for point-like defects of pot-type insulators, comprising the following steps:

A: Clean and dry the inside of the three-step casting mold and then vacuumize;

B: Epoxy resin and alumina powder materials are evenly mixed and heated, poured into the three-step casting mold through the nozzle of the three-step casting mold, and solidified twice, and the three-step block is obtained after demoulding;

C: Smooth the riser and edge of the three-step block, and adjust the thickness of the three steps between 25mm-35mm, 55mm-65mm, and 85mm-95mm;

D: Process multiple flat-bottomed holes with different diameters on the upper surface of each step of the three steps. The center of the flat-bottomed hole is located on the transverse centerline of the step surface, and the distance between two adjacent flat-bottomed holes is 10mm.

In step C, the thicknesses of the three steps are 30mm, 60mm and 90mm respectively.

In the step C, the widths of the three steps are all 40 mm, and the lengths are all 100 mm.

In the step D, 6 flat-bottomed holes are processed on the upper surface of each step, and the hole depth of each flat-bottomed hole is the same as the hole diameter, and the hole diameters of the 6 flat-bottomed holes are respectively 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm .

Step E is also included, paste the identification number in lead at 4mm from the edge of each flat-bottomed hole.

The present invention utilizes the differences in radiation absorbed doses of flat-bottomed holes arranged at different depths on the surface of the steps, and by observing the minimum detectable apertures of the point-like defects of basin-type insulators with different thicknesses at different distances from the detection site to the imaging plate, it is determined that the detection system can The smallest point defect detected, so as to conveniently and intuitively judge the detection sensitivity of the point defect of the digital ray inspection system.

Description of drawings

Fig. 1 is a schematic diagram of the structure of a digital radiographic detection test block for point defects of basin-type insulators according to the present invention.

Detailed ways

As shown in Figure 1, the digital ray detection test block for point-like defects of pot-type insulators according to the present invention is a three-step block structure made of a mixture of epoxy resin and aluminum powder materials. The width of the three steps is 40mm, and the length The heights of the upper surfaces of the three steps from bottom to top are 25mm-35mm, 55mm-65mm, and 85mm-95mm respectively, and the upper surface of each step is provided with a plurality of flat-bottomed holes 1 with different apertures; flat-bottomed holes 1 The center is located on the transverse centerline of the stepped surface, and the distance between two adjacent flat-bottomed holes 1 is 10 mm. In this embodiment, six flat-bottomed holes 1 are provided on the upper surface of each step, and the hole depth of each flat-bottomed hole 1 is the same as the hole diameter, and the hole diameters of the six flat-bottomed holes 1 are respectively 0.5mm, 1mm, 2mm, 3mm, and 4mm. , 5mm, and the upper surface heights of the three steps from bottom to top are 30mm, 60mm and 90mm respectively.

The manufacturing method of the digital ray detection test block for point-like defects of pot-type insulators according to the present invention comprises the following steps:

A: Clean and dry the inside of the three-step casting mold and then vacuumize;

B: Epoxy resin and alumina powder materials are evenly mixed and heated, poured into the three-step casting mold through the nozzle of the three-step casting mold, and solidified twice, and the three-step block is obtained after demoulding;

C: Smooth the riser and edge of the three-step block, and adjust the thickness of the three steps between 25mm-35mm, 55mm-65mm, and 85mm-95mm;

D: Process a plurality of flat-bottomed holes 1 with different apertures on the upper surface of each of the three steps. The center of the flat-bottomed holes 1 is located on the transverse centerline of the step surface, and the distance between two adjacent flat-bottomed holes 1 is 10mm;

E: At 4mm from the edge of each flat-bottomed hole 1, paste the identification number in lead.

In this embodiment, the thickness of the three steps is 30mm, 60mm and 90mm respectively; the width of the three steps is 40mm, and the length is 100mm; the upper surface of each step of the three steps is processed with 6 flat-bottomed holes 1, each The hole depth of the flat-bottomed holes 1 is the same as the hole diameter, and the hole diameters of the six flat-bottomed holes 1 are 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm, respectively.

In digital radiography detection, there are three parameters for judging the sensitivity of digital radiography, which are spatial resolution, pixel resolution, and density resolution. When the point defect is close to the imaging plate, the density resolution is better, but the spatial resolution is worse; conversely, when the point defect is far away from the imaging plate, the spatial resolution is better, but the density resolution is worse. Therefore, there is an appropriate distance at which both the spatial resolution and the density resolution are acceptable and the digital ray sensitivity can be optimized. This distance is the optimal distance in digital ray transillumination. Through the digital ray detection test block of the point defect of the pot insulator and the support of different distances, the imaging sensitivity of the point defect at different distances from the imaging plate can be tested, so as to determine the optimal distance.

When using the digital ray detection test block for point-like defects of pot-type insulators according to the present invention to perform digital ray sensitivity detection for point-like defects of pot-type insulators, the ray beam is vertically passed through the test block, and then the ray is received by an imaging device to form an image. The difference between the depth of flat-bottomed holes 1 and the absorbed dose of radiation is determined by observing the minimum detectable aperture of the point-shaped defects of basin-type insulators with different thicknesses at different distances from the detection part to the imaging plate to determine the minimum point-shaped defects that can be detected by the detection system , so as to conveniently and intuitively judge the detection sensitivity of the point defect of the digital ray inspection system.

Claims (10)

1. A digital ray detection test block for point-like defects of pot-type insulators, characterized in that: the digital ray-detection test block for point-like defects of pot-type insulators is a three-step ladder made by mixing epoxy resin and alumina powder materials Block structure, the height of the upper surface of the three steps from bottom to top is between 25mm-35mm, 55mm-65mm, 85mm-95mm respectively, and the upper surface of each step is provided with multiple flat-bottomed holes with different apertures. 2. The digital ray detection test block for point defects of pot-type insulators according to claim 1, wherein the center of the flat-bottomed hole is located on the transverse centerline of the stepped surface, and the distance between two adjacent flat-bottomed holes is 10mm. 3. The digital ray detection test block for point defects of pot-type insulators according to claim 2, characterized in that: the upper surface of each step is provided with 6 flat-bottomed holes, and the hole depth of each flat-bottomed hole is the same as the hole diameter , The diameters of the six flat-bottomed holes are 0.5mm, 1mm, 2mm, 3mm, 4mm, and 5mm. 4. The digital radiography test block for spot defects of pot-type insulators according to claim 3, wherein the heights of the upper surfaces of the three steps from bottom to top are respectively 30mm, 60mm and 90mm. 5. The digital ray detection test block for point defects of pot-type insulators according to claim 4, characterized in that: the widths of the three steps are all 40mm, and the lengths are all 100mm. 6. A method for making a digital ray detection test block for point-like defects of pot-type insulators, comprising the following steps: A: Clean and dry the inside of the three-step casting mold and then vacuumize; B: Epoxy resin and alumina powder materials are evenly mixed and heated, poured into the three-step casting mold through the nozzle of the three-step casting mold, and solidified twice, and the three-step block is obtained after demoulding; C: Smooth the riser and edge of the three-step block, and adjust the thickness of the three steps between 25mm-35mm, 55mm-65mm, and 85mm-95mm; D: Process multiple flat-bottomed holes with different diameters on the upper surface of each step of the three steps. The center of the flat-bottomed hole is located on the transverse centerline of the step surface, and the distance between two adjacent flat-bottomed holes is 10mm. 7. The manufacturing method of digital ray detection test block for point-like defects of basin-type insulators according to claim 6, characterized in that: in the step C, the thicknesses of the three steps are 30mm, 60mm and 90mm respectively. 8. The manufacturing method of digital ray detection test block for point-like defects of pot-type insulators according to claim 7, characterized in that: in the step C, the width of the three steps is 40 mm, and the length is 100 mm. 9. The manufacturing method of the digital ray detection test block for point-like defects of pot-type insulators according to claim 8, characterized in that: in the D step, the upper surface of each step is processed with 6 flat-bottomed holes, and each flat-bottomed The hole depth is the same as the hole diameter, and the hole diameters of the six flat-bottomed holes are 0.5mm, 1mm, 2mm, 3mm, 4mm, and 5mm respectively. 10. The manufacturing method of digital ray detection test block for point-like defects of pot-type insulators according to claim 9, characterized in that it further comprises step E of pasting a lead-type identification number at 4 mm from the edge of each flat-bottomed hole.

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