A nondestructive testing device for pressure vessel welds

Abstract

The present invention discloses a non-destructive flaw detection device for pressure vessel welds, relating to the technical field of flaw detection devices. RT is used as a basic method for non-destructive flaw detection of pressure vessel welds, and the device mainly optimizes the linear distance and emission direction of X-rays relative to the weld. Specifically, the device is based on first-order displacement sensors and second-order sensors arranged along four-directional positions on a joint plate, and the installation methods of the two are restricted to avoid motion interference. The purpose is to preliminarily obtain the distance between the RT detection probe and the weld structure surface. The key lies in using an adaptive push rod assembly to change the distance between each electrical contact and the weld structure surface through an electrical sensing method. The purpose is to maintain the setting angle of the X-rays in the RT detection probe relative to the weld structure, which is specifically manifested in the pushing stroke Tc and the linear distance TL. The relative distance of the RT detection probe is readjusted with the two as the key to adjust the X-ray radiation intensity, thereby indirectly maintaining the accuracy of the detection data.

Description

Technical Field

[0001] The present invention relates to the technical field of flaw detection equipment, in particular to a non-destructive flaw detection equipment for pressure vessel welds. Background Art

[0002] The key part of the pressure vessel molding and preparation process is welding technology. Please refer to the specific contents in the relevant documents such as publication numbers CN117564630A and CN119035962A. Welding quality is one of the key factors affecting sealing and structural strength. Non-destructive testing methods such as radiography (RT) and ultrasonic testing (UT) can be used to detect internal defects in welds. Please refer to the relevant contents in publication numbers CN118130373A and CN115830013A.

[0003] The key to nondestructive testing lies in the real-time acquisition of parameter curves. Since pressure vessel structures can be complex, RT is often used. A significant difference from UT is that there is no need for the probe to contact the structural surface. The core lies in transillumination arrangement and image analysis, rather than physical contact requirements. However, it is worth further explaining that:

[0004] The quality of flaw detection in the RT detection method is directly related to the detection distance (the distance between the X-ray probe and the structural surface). Referring to the geometric unsharpness formula and combining it with the wall thickness of the pressure vessel, the penetration ability of RT on thick-walled materials (such as >50mm) is significantly reduced, and a high-energy X-ray source is required. When the penetration thickness increases, the detection sensitivity may decrease, and it is necessary to compensate by shortening the distance or increasing the X-ray energy, but the influence of geometric unsharpness needs to be balanced. Therefore, in the actual operation process, the detection accuracy may be directly affected by multiple factors such as distance changes and structural surface thickness. This application proposes a solution to this problem. Summary of the Invention

[0005] The purpose of the present invention is to provide a non-destructive flaw detection device for pressure vessel welds. The RT method used in non-destructive flaw detection of pressure vessel welds is described. Although physical contact is not required, in actual operation, the distance between the X-ray probe and the structural surface and the thickness change of the structural surface itself will indirectly affect the accuracy of the detection data.

[0006] The objectives of the present invention can be achieved by the following technical solutions: A pressure vessel weld nondestructive testing device, comprising a mechanical arm assembly and an assembly control assembly, wherein a joint assembly is provided at the transmission end position of the mechanical arm assembly, wherein the joint assembly comprises a joint plate, a coupling rod, and an RT detection probe, wherein the RT detection probe is installed at the center point of the coupling rod, and the ray direction of the RT detection probe is parallel to the setting direction of the coupling rod;

[0007] The joint plate is provided with a first-order displacement sensor, a second-order displacement sensor and a push rod assembly, and a four-way positioning module associating the first-order displacement sensor, the second-order displacement sensor and the push rod assembly is established in the assembly control assembly.

[0008] It is further configured that: the first-order displacement sensor and the push rod assembly are arranged in a reversing array along the four directions on the joint plate.

[0009] It is further configured as follows: the coupling rod is installed on the mechanical arm assembly, the joint plate is rotatably connected to the coupling rod, and a gear drive assembly corresponding to the joint plate is provided on the coupling rod.

[0010] It is further configured as follows: the gear drive assembly includes a driving gear, a cooperating gear and a driving motor, the driving gear is installed on the output shaft position of its driving motor, the cooperating gear is fixedly connected to the joint plate and is rotationally connected to the coupling rod, and the cooperating gear is meshed with the driving gear.

[0011] It is further configured as follows: one end of the first-order displacement sensor and the second-order displacement sensor is movably connected to the joint plate, and the other end of the second-order displacement sensor is movably connected to the first-order displacement sensor.

[0012] It is further configured as follows: the first-order displacement sensor is tilted in the direction close to the RT detection probe, the second-order displacement sensor is tilted in the direction away from the RT detection probe, and a triangular contact structure is formed between the second-order displacement sensor and the first-order displacement sensor, and a ball is provided at the end position of the transmission rod of the first-order displacement sensor.

[0013] It is further configured that: the setting direction of the push rod assembly is parallel to the setting direction of the coupling rod, and an electrical contact is installed at the end position of the transmission rod of the push rod assembly.

[0014] The present invention has the following beneficial effects:

[0015] Based on the non-destructive testing method of pressure vessel welds, specifically the RT detection method, the key is to optimize the linear distance and emission direction of X-rays relative to the weld. The RT detection probe is installed in the middle position of the joint plate and its installation direction is maintained. The key is to use the first-order displacement sensor and the second-order sensor set along the four-way position on the joint plate as the basis, and then combine to form a four-way positioning structure, and further restrict the installation method of the two to ensure that the two can perform normal displacement sensing action while avoiding motion interference problems. Its initial purpose is to obtain the distance between the RT detection probe and the weld structure surface;

[0016] Based on the above content, considering the angle problem between the X-ray and the weld structure, the present invention specifically needs to ensure that the X-ray and the weld structure surface are in a completely vertical state. For this purpose, a push rod assembly is added to cooperate with the four-way positioning structure. The push rod assembly does not participate in the displacement sensing process. The key is the electrical sensing method formed by the electrical contact, so that the distance between the electrical contact and the weld structure surface is driven by the active action of the push rod assembly. The purpose is to ensure that each electrical contact contacts the weld structure surface, but it is also necessary to maintain the joint plate and the weld structure surface in a relatively vertical state, which is specifically manifested in the pushing stroke Tc and the linear distance TL. The two are used as the key to readjust the relative distance of the RT detection probe and adjust the X-ray radiation intensity, thereby indirectly maintaining the accuracy of the detection data. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a schematic structural diagram of a pressure vessel weld non-destructive testing device proposed by the present invention;

[0019] Figure 2 This is a structural schematic diagram of a joint assembly in a pressure vessel weld non-destructive testing device proposed by the present invention;

[0020] Figure 3 This is a cross-sectional view of a joint plate in a pressure vessel weld non-destructive testing device proposed by the present invention;

[0021] Figure 4 This is a schematic structural diagram of a gear drive assembly in a pressure vessel weld non-destructive testing device proposed by the present invention;

[0022] Figure 5 This is a schematic diagram of the operation of a four-way positioning module in a pressure vessel weld non-destructive testing device proposed by the present invention.

[0023] In the figure: 1. Robotic arm assembly; 2. Assembly control assembly; 3. Connector plate; 4. First-order displacement sensor; 5. Push rod assembly; 6. Electrical contact; 7. Second-order displacement sensor; 8. RT detection probe; 9. Gear drive assembly; 10. Coupling rod. DETAILED DESCRIPTION

[0024] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Example 1: This article describes the RT method for non-destructive testing of pressure vessel welds. Although physical contact is not required, in actual operation, the distance between the X-ray probe and the structural surface, as well as the thickness change of the structural surface itself, will indirectly affect the accuracy of the test data. To address this issue, the present invention proposes the following technical solutions:

[0026] Reference Figures 1 to 4 In this embodiment, a pressure vessel weld nondestructive testing device includes a robotic arm assembly 1 and an assembly control assembly 2. A joint assembly is provided at the transmission end of the robotic arm assembly 1. The joint assembly includes a joint plate 3, a coupling rod 10, and an RT detection probe 8. The RT detection probe 8 is installed at the center point of the coupling rod 10, and the ray direction of the RT detection probe 8 is parallel to the installation direction of the coupling rod 10.

[0027] A first-order displacement sensor 4, a second-order displacement sensor 7, and a push rod assembly 5 are provided on the joint plate 3. A four-way positioning module associating the first-order displacement sensor 4, the second-order displacement sensor 7, and the push rod assembly 5 is established in the assembly control assembly 2. The first-order displacement sensor 4 and the push rod assembly 5 are arranged in a reversing array along their four-way positions on the joint plate 3. The coupling rod 10 is mounted on the robotic arm assembly 1. The joint plate 3 is rotatably connected to the coupling rod 10. The coupling rod 10 is provided with a gear drive assembly 9 corresponding to the joint plate 3.

[0028] The gear drive assembly 9 includes a driving gear, a cooperating gear and a driving motor. The driving gear is installed on the output shaft of its driving motor. The cooperating gear is fixedly connected to the joint plate 3 and is rotationally connected to the coupling rod 10, and the cooperating gear is meshed with the driving gear.

[0029] Basic Principle: Briefly explain the nondestructive testing process of welds in the pressure vessel preparation process: Taking into account the complex structural surfaces in the pressure vessel, the present invention is mainly based on the RT nondestructive testing principle, and briefly explain the RT nondestructive testing principle as follows:

[0030] X-rays or gamma rays are used as the penetration source, and their high energy characteristics are used to penetrate metal materials. During the penetration process, materials with different densities absorb and scatter the rays to different degrees, resulting in intensity attenuation differences. The density of internal defects in the weld (such as pores, slag inclusions, and cracks) is different from that of the base material, resulting in changes in the ray attenuation coefficient in the defective area, forming local blackness differences on the film or digital detector. Compared with ultrasonic non-destructive testing:

[0031] A non-contact physical method can be used, so there is no need to grind and clean the weld. In this invention, the robot arm assembly 1 is used as the action part in the whole non-destructive testing process. The essence can be referred to Figure 1 and Figure 2 The RT detection probe 8 serves as the basic structure for emitting X-rays, while the assembly control component 2 serves as the X-ray generator and receiver. Considering that the rays are harmful to the human body, a wireless remote control unit needs to be added to the assembly control component 2. This part will not be explained in detail.

[0032] It needs to be directly stated that: it is necessary to ensure that the emission direction of the X-rays in the RT detection probe 8 is completely parallel to the direction of the coupling rod 10. The non-destructive testing trajectory can be directly achieved by controlling the movement mode of the robotic arm assembly 1. However, it needs to be further stated that: considering the problem of the thickness of the pressure vessel structure, the radiation intensity of the X-rays is also one of the key factors affecting the detection quality, and because the RT non-destructive testing method is mainly non-contact, the distance between the RT detection probe 8 and the structural surface is also one of the factors affecting the X-ray radiation intensity. For this, the present invention is based on the conventional RT non-destructive testing method, and is mainly used for real-time control of the distance between the RT detection probe 8 and the structural surface. The movement mode and structural characteristics of the robotic arm assembly 1 are not explained in detail in the present invention.

[0033] Example 2: Based on the basic principles proposed in Example 1, the overall structure is supplemented as follows:

[0034] One end of the first-order displacement sensor 4 and the second-order displacement sensor 7 are movably connected to the joint plate 3, and the other end of the second-order displacement sensor 7 is movably connected to the first-order displacement sensor 4. The first-order displacement sensor 4 is tilted in the direction close to the RT detection probe 8, and the second-order displacement sensor 7 is tilted in the direction away from the RT detection probe 8, and a triangular contact structure is formed between the second-order displacement sensor 7 and the first-order displacement sensor 4. A ball is provided at the end of the transmission rod of the first-order displacement sensor 4, and the setting direction of the push rod assembly 5 is parallel to the setting direction of the coupling rod 10, and an electrical contact 6 is installed at the end of the transmission rod of the push rod assembly 5.

[0035] Program Description: Figure 2 and Figure 3For example, it can be directly understood that the direction of the X-ray in the RT detection probe 8 is completely perpendicular to the surface of the joint plate 3. The distance between the RT detection probe 8 and the structural surface is mainly directly controlled by the joint plate 3. The essence is:

[0036] When the robot arm assembly 1 drives the whole joint assembly to move adaptively, the key is that the ball in the first-order displacement sensor 4 first contacts the workpiece structure surface and refers to Figure 3 It can be seen from the positional relationship between the first-order displacement sensor 4 and the second-order displacement sensor 7 that the first-order displacement sensor 4, the second-order displacement sensor 7 and the connector plate 3 have the ability to move. Take one of the first-order displacement sensors 4 as an example;

[0037] When the ball contacts the structural surface of the workpiece, the first-order displacement sensor 4 can only tilt in the direction close to the RT detection probe 8. In this process, the tilting mode of the first-order displacement sensor 4 is mainly sensed by the second-order displacement sensor 7. In this process, the displacement value of the first-order displacement sensor 4 may also change. Because a triangular contact structure is formed between the second-order displacement sensor 7 and the first-order displacement sensor 4, the triangular contact structure is relatively stable. The following supplementary explanation is given about its purpose:

[0038] The structural surface of the pressure vessel workpiece is not completely horizontal or smooth. When the overall joint assembly moves with the robot arm assembly 1, the first-order displacement sensor 4 and the second-order displacement sensor 7 are mainly used to detect the distance between the joint plate assembly and the structural surface. However, the first-order displacement sensor 4 cannot interfere with the movement of the joint plate assembly. Figure 3 Taking the setting direction of each first-order displacement sensor 4 as an example, when the overall joint assembly moves to the left, each first-order displacement sensor 4 can be tilted accordingly, which can meet the distance detection requirements and avoid motion interference.

[0039] The four-way positioning module proposed in the present invention is mainly realized by the first-order displacement sensor 4 and the second-order displacement sensor 7. The key is to ensure that the first-order displacement sensor 4 is set along the four-way position. Specifically, each first-order displacement sensor 4 is set at 90 degrees along the center point of the joint plate 3, and the entire joint plate needs to be directional rotated under the action of the gear drive assembly 9 to ensure that the setting direction between the two opposing first-order displacement sensors 4 is completely consistent with the walking direction of the joint assembly. The purpose is also to avoid motion interference.

[0040] It is also necessary to add a push rod assembly 5 for the walking trajectory of the joint assembly. It is necessary to ensure that the setting direction of the push rod assembly 5 is completely consistent with the setting direction of the coupling rod 10, and further ensure that the push rod assembly 5 is associated with the setting direction of the first-order displacement sensor 4 and the second-order displacement sensor 7. The purpose is: to extend or contract the push rod assembly 5 in the corresponding position, and the purpose is to ensure that the electrical contact 6 contacts the structural surface of the pressure vessel. On the basis of adjusting the distance between the RT detection probe 8 and the pressure vessel structural surface, it is also necessary to further maintain the joint plate 3 and the weld structural surface in a relatively horizontal state, so as to ensure that the X-rays emitted by the RT detection probe 8 are completely perpendicular to the weld structural surface. The key explanation of this method is: during the overall non-destructive testing process, the RT detection probe 8 is maintained within a certain distance range from the structural surface, but the emitted X-rays are avoided from being excessively dispersed, making it difficult to concentrate on the weld and affecting the detection quality. For this, it is also necessary to ensure that the emission angle of the X-rays is completely perpendicular to the weld structural surface. Its essence is to ensure that the X-rays completely act on the weld.

[0041] Example 3: In combination with Example 1 and Example 2, the following supplementary explanation is given for the four-way positioning module:

[0042] Reference Figure 5 In conjunction with the first embodiment, the functions of the assembly control component of the present invention are as follows: 1. Serving as a generator and receiver for the RT detection probe 8; 2. Serving as a control end for the four-way positioning module; 3. Serving as a wireless transmission / reception section for real-time data. In addition, there are the following supplementary explanations:

[0043] S1: During the non-destructive testing process, a low current needs to be passed through the pressure vessel. After the electrical contact 6 contacts the structural surface of the pressure vessel, a closed loop circuit is formed between the electrical contact 6 and the pressure vessel, thereby representing the arrangement of the joint plate 3. It should be briefly explained that in RT non-destructive testing, the current does not directly affect the inspection structure.

[0044] S2: Reference Figure 3 To illustrate: The distance between the joint plate 3 and the structural surface can be calculated by combining the setting mode of each group of first-order displacement sensors 4 and second-order displacement sensors 7 and the values ​​obtained therein, and Ta and Tb are used to represent the displacement values ​​of the first-order displacement sensor 4 and the second-order displacement sensor 7 respectively. Figure 3 Taking the arrangement positions of the first-order displacement sensor 4 and the second-order displacement sensor 7 as an example, the linear distance between the joint plate 3 and the ball can be obtained by referring to the trigonometric function. In this way, the distance between the RT detection probe 8 and the structural surface can be preliminarily obtained;

[0045] S3: When the joint plate 3 continues to move toward the structural surface, based on S2, it is necessary to ensure that after the ball on each first-order displacement sensor 4 contacts the structural surface, the essence is that Ta and Tb will change. The linear distance TL between the joint plate 3 and the structural surface is obtained based on Ta and Tb, and an action command is sent to each push rod assembly 5 based on TL. The purpose is to ensure that each electrical contact 6 gradually contacts the pressure vessel. To this end, it is necessary to ensure that the closed-loop circuit formed by each electrical contact 6 is independent of each other.

[0046] When the closed-loop circuit connected to one of the electrical contacts 6 is in an energized state, the push rod assembly 5 in the corresponding position stops running until the closed-loop circuit connected to each electrical contact 6 is in an energized state. The pushing stroke Tc in each push rod assembly 5 is recorded. Considering the complexity of the structural surface, each pushing stroke Tc will not be completely consistent, and the maximum and minimum values ​​are calibrated. The adjustment stroke To is further obtained by referring to the linear distance TL and the minimum value of the pushing stroke Tc. To is mainly used to indicate the moving distance of the joint plate 3 further along the linear direction close to the workpiece structural surface driven by the robotic arm assembly 1, so as to finally adjust the X-ray radiation intensity emitted by the RT detection probe 8.

[0047] In summary, the RT method is used as the basic method for non-destructive testing of pressure vessel welds. It is mainly aimed at optimizing the linear distance and emission direction of X-rays relative to the weld. Specifically, it is based on the first-order displacement sensor and the second-order sensor arranged along the four-way position on the joint plate. The installation method of the two is restricted to avoid motion interference. The purpose is to preliminarily obtain the distance between the RT detection probe and the weld structure surface. The key is to change the distance between each electrical contact and the weld structure surface through electrical sensing through the adaptive push rod assembly. The purpose is to maintain the setting angle of the X-ray in the RT detection probe relative to the weld structure, which is specifically manifested in the pushing stroke Tc and the linear distance TL. The relative distance of the RT detection probe is readjusted with the two as the key to adjust the X-ray radiation intensity, thereby indirectly maintaining the accuracy of the detection data.

[0048] The above contents are merely examples and explanations of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0049] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0050] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A pressure vessel weld non-destructive testing device, comprising a robotic arm assembly (1) and an assembly control assembly (2), characterized in that: A joint assembly is provided at the transmission end position of the mechanical arm assembly (1), the joint assembly comprising a joint plate (3), a coupling rod (10) and an RT detection probe (8), the RT detection probe (8) being installed at the center point of the coupling rod (10), and the ray direction of the RT detection probe (8) being parallel to the setting direction of the coupling rod (10); The joint plate (3) is provided with a first-order displacement sensor (4), a second-order displacement sensor (7) and a push rod assembly (5), and a four-way positioning module associating the first-order displacement sensor (4), the second-order displacement sensor (7) and the push rod assembly (5) is established in the assembly control component (2); One end of the first-order displacement sensor (4) and the second-order displacement sensor (7) is movably connected to the joint plate (3), and the other end of the second-order displacement sensor (7) is movably connected to the first-order displacement sensor (4). The first-order displacement sensor (4) is tilted in a direction close to the RT detection probe (8), and the second-order displacement sensor (7) is tilted in a direction away from the RT detection probe (8). A triangular contact structure is formed between the second-order displacement sensor (7) and the first-order displacement sensor (4). A ball is provided at the end of the transmission rod of the first-order displacement sensor (4).

2. The pressure vessel weld nondestructive testing equipment according to claim 1, characterized in that: The first-order displacement sensor (4) and the push rod assembly (5) are arranged in a reversing array along the four-directional positions on the joint plate (3).

3. The pressure vessel weld nondestructive testing equipment according to claim 1, characterized in that: The coupling rod (10) is mounted on the mechanical arm assembly (1), the joint plate (3) is rotatably connected to the coupling rod (10), and a gear drive assembly (9) corresponding to the joint plate (3) is provided on the coupling rod (10).

4. The pressure vessel weld non-destructive testing equipment according to claim 3, characterized in that: The gear drive assembly (9) comprises a driving gear, an assisting gear and a driving motor, wherein the driving gear is mounted on the output shaft of the driving motor, the assisting gear is fixedly connected to the joint plate (3) and is rotationally connected to the coupling rod (10), and the assisting gear is meshed with the driving gear.

5. The pressure vessel weld non-destructive testing equipment according to claim 1, characterized in that: The setting direction of the push rod assembly (5) is parallel to the setting direction of the coupling rod (10), and an electrical contact (6) is installed at the end position of the transmission rod of the push rod assembly (5).

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