Uninterrupted under-pressure safe opening-increasing construction method for PE (Poly Ethylene) electric and hot melting pipelines

Abstract

The invention discloses an uninterrupted under-pressure safe opening-increasing construction method for PE electric and hot melting pipelines, and relates to the field of pipeline construction. Self-adaptive path planning and cavity sealing verification are carried out before trepanning; self-adaptive through hole opening is carried out; after tapping is completed and the cutter is withdrawn, the ball valve is closed, a welding seam is checked, the hole-shrinkage-free under-pressure tapper and the pressure testing device are removed after checking is correct, and under-pressure opening increasing construction is completed; according to the PE electric and hot melting pipeline opening increasing construction method, on the basis of a traditional non-stop pressurized opening increasing technology, after-welding cavity sealing verification and non-shrinkage penetrating trepanning are carried out step by step, means such as visual guidance assembly and three-dimensional scanning registration are further introduced, and the defects of an existing technology in the aspects of positioning precision, welding quality and the like are overcome to a certain degree.

Description

Technical Field

[0001] This invention relates to pipeline construction technology, specifically to a method for uninterrupted pressurized and safe expansion of PE electrofusion pipelines. Background Technology

[0002] Polyethylene (PE) pipes, due to their excellent corrosion resistance, good flexibility, lightweight yet high strength, and convenient connection characteristics, have been widely used in municipal and industrial pipeline projects such as urban gas transmission and water supply and drainage. With the continuous expansion of pipeline networks and the increasingly urgent need for upgrading and renovating aging networks, how to safely and reliably add branch interfaces (referred to as pressurized expansion joints) under pressurized operation (i.e., without interruption of supply or venting) has become a key technical challenge in pipeline operation and maintenance and emergency repair. Traditional shutdown construction not only causes large-scale power outages and socio-economic losses but may also trigger secondary safety risks. Therefore, the research and application of pressurized expansion joint technology without interruption of supply has significant practical implications.

[0003] Currently, the mainstream PE pipe pressurized expansion construction technology still has certain limitations and cannot fully meet the requirements of high-quality and high-safety projects. Its main shortcomings are reflected in the following aspects:

[0004] The low positioning accuracy of pipe fitting assembly and the reliance on manual experience for welding quality result in poor controllability: In traditional processes, the installation and positioning of saddle-shaped electrofusion / thermal fusion pipe fittings largely depend on manual visual inspection or simple measuring tools, making it difficult to accurately control the fit, coaxiality, and orientation angle between the welding surface of the fitting and the main pipeline. Key parameters of the welding process (especially electrofusion welding), such as heating temperature, energizing time, applied pressure, and molten state (e.g., molten slurry rise height and uniformity), lack real-time, objective quantitative monitoring methods and rely entirely on the operator's experience. Manual visual inspection is highly subjective and prone to internal defects such as insufficient welding (cold welding), excessive melting (over-welding), or local lack of fusion. These hidden defects pose a risk of leakage during long-term pressurized operation of the pipeline, and the causes are difficult to trace afterward.

[0005] Poor adaptability of opening paths: When creating curved surfaces and holes on main pipelines to match saddle-shaped fittings, traditional methods often employ fixed-path mechanical opening or simple contour machining. However, due to potential morphological deviations such as ellipticity, local depressions, protrusions, or surface unevenness during the manufacturing, transportation, and laying of PE pipes, fixed-path openings easily lead to irregular opening edges, diameter deviations, or mismatches with the geometric features of the fitting welding surface, thus affecting the fusion quality and sealing reliability of subsequent welding. Furthermore, some processes use reduced-diameter opening tools to ensure smooth opening, which, while reducing the difficulty of opening, decreases the flow cross-sectional area of ​​the main pipeline, introducing additional flow resistance and potential eddy current corrosion risks, making it unsuitable for trunk pipelines with high flow stability requirements.

[0006] The traditional process suffers from a disconnect between pre-drilling cavity sealing verification and path planning, resulting in weak process monitoring. After pipe welding, drilling equipment is typically installed directly for drilling, lacking an independent and rigorous pressure test to ensure the sealing of the cavity formed by the drill, the ball valve, and the pipe before drilling. Furthermore, the drilling path planning fails to adequately consider the three-dimensional morphological deviations of the actual pipe surface, making it impossible to generate an adaptive machining path that dynamically matches the geometric features of the welded pipe surface. During drilling, real-time visual monitoring and intelligent status recognition of the working interface (such as tool status, material cutting conditions, and the presence of abnormal melting or cracks) are lacking, making it difficult to promptly detect and handle unexpected situations, potentially leading to drilling failure or damage to the main pipeline.

[0007] Therefore, there is an urgent need for a method for uninterrupted, pressurized, and safe expansion of PE electrofusion and thermofusion pipelines that integrates construction guidance and adaptive control to solve the above-mentioned technical problems. Summary of the Invention

[0008] The purpose of this invention is to provide a method for uninterrupted pressurized and safe expansion of PE electrofusion pipes, in order to solve the problems of low positioning accuracy and unstable welding quality in the existing technology.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for uninterrupted pressurized safe expansion of PE electrofusion and thermofusion pipelines, comprising the following steps:

[0010] S1: Visual-guided assembly and welding;

[0011] S2: Adaptive path planning and cavity sealing verification before opening;

[0012] S3: Adaptive through-hole;

[0013] S4: After the hole is opened and the tool is retracted, close the ball valve, inspect the weld, and remove the non-reduced diameter pressure hole opener and pressure testing device after the inspection is correct to complete the pressure expansion construction.

[0014] Furthermore, S1 specifically includes:

[0015] S101: Install the saddle-shaped electrofusion fitting assembly with a full-bore ball valve to the target location on the PE main pipeline;

[0016] S102: During installation, a laser contour sensor is used to perform a three-dimensional scan of the contact area between the welding surface of the pipe fitting and the main pipe. The obtained real-time three-dimensional point cloud data is then registered and compared with the pre-stored standard digital model of the pipe fitting welding surface.

[0017] S103: Based on the attitude adjustment guidance output by the comparison results, the component is accurately positioned and then electrofusion welding is performed.

[0018] Furthermore, S2 specifically includes:

[0019] S201: After welding is completed and cooled, keep the ball valve open and install the non-reduced diameter pressurized hole punch with integrated coaxial laser profile sensor onto the ball valve;

[0020] S202: After installation, a sealing pressure test is performed on the sealed cavity consisting of the port opener, the open ball valve, and the pipe fittings.

[0021] S203: After passing the pressure test, the laser profile sensor of the hole opener is used to scan the surface of the main pipe in the area to be opened below through the open ball valve to obtain the actual three-dimensional shape data of the area to be processed.

[0022] S204: The actual three-dimensional topography data is registered with the standard digital model in real time, and the control system automatically calculates and generates an adaptive hole-opening processing path that matches the geometric features of the welding surface of the pipe fitting.

[0023] Furthermore, S3 specifically includes:

[0024] S301: Based on the generated adaptive processing path, drive the non-reducing diameter pressurized tapper to perform a one-time through-hole opening on the main pipe, and form a 90° through-hole in the direction perpendicular to the pipe axis that penetrates the inner and outer walls of the main pipe.

[0025] S302: During the hole-opening process, the working interface is monitored in real time by an image acquisition device introduced near the welding area, and the working status is analyzed based on image recognition.

[0026] Furthermore, the standard digital model in S102 is a benchmark data model constructed by performing high-precision three-dimensional scanning on the welding surface of the saddle-shaped electrofusion pipe fitting and extracting its surface curvature, key contour lines and best-fit plane information.

[0027] Furthermore, in S301, the driving mechanism for the hole opener to perform hole opening is a multi-axis robotic arm. This robotic arm can dynamically adjust the feed speed and cutting depth according to the adaptive machining path and the real-time feedback from the laser contour sensor.

[0028] Furthermore, the image recognition analysis in S302 specifically includes: performing real-time dynamic comparison between the video stream captured by the image acquisition device and the preset qualified welding and opening status feature library; if the feature is found to deviate from the preset threshold, an alarm is triggered.

[0029] Compared with existing technologies, the PE electrofusion and thermofusion pipeline uninterrupted pressurized safety expansion method provided by this invention, based on traditional uninterrupted pressurized expansion technology, implements post-weld cavity sealing verification and non-reduction through-hole opening in stages, and further introduces visual-guided assembly and three-dimensional scanning registration, which to a certain extent solves the shortcomings of existing processes in terms of positioning accuracy and welding quality. Specific technical effects include the following:

[0030] 1. After the pipe fittings are welded and before the hole is opened, an independent sealing pressure test is performed on the sealed cavity consisting of the non-reducing pressure tap, the opened ball valve and the pipe fittings. This can detect and eliminate potential leakage hazards in the cavity in advance and avoid the risk of media leakage during the hole opening process.

[0031] 2. During the installation phase, a laser contour sensor is used to perform a three-dimensional scan of the contact area between the welding surface of the pipe fitting and the main pipeline, and the scan is compared with the pre-stored standard digital model in real time. Based on the posture adjustment guidance, the components are accurately positioned, which significantly improves the fit and coaxiality of the welding surface and overcomes the positioning error of manual visual measurement. At the same time, a multi-axis robotic arm is used to drive the hole opener, which can dynamically adjust the feed speed and cutting depth according to the adaptive path and real-time feedback from the laser contour sensor to ensure the size and position accuracy of the hole through in one go. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0033] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention;

[0034] Figure 2 This is a process flow diagram of Embodiment 2 of the present invention. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0036] As attached Figure 1 As shown:

[0037] Example 1:

[0038] This invention provides a method for uninterrupted, pressurized, and safe expansion joint construction of PE electrofusion and thermofusion pipes, comprising the following steps:

[0039] S1: Install the prefabricated saddle-shaped electrofusion fittings and ball valve assemblies to the target position of the PE main pipeline and perform electrofusion welding;

[0040] S2: After welding, install the non-reduced diameter pressurized opening device onto the ball valve, and test the pressure of the sealed cavity formed by the opening device, ball valve and pipe fittings.

[0041] S3: After passing the pressure test, use a non-reducing live tap to perform a one-time through-hole opening on the main pipeline;

[0042] S4: After the hole is opened and the tool is retracted, close the ball valve, inspect the weld, and remove the non-reduced diameter pressure hole opener and pressure testing device after the inspection is correct to complete the pressure expansion construction.

[0043] Working Principle: In Example 1, the prefabricated saddle-shaped electrofusion fittings and ball valve assembly are first precisely installed to the target position of the PE main pipeline and electrofused to form a basic connection structure suitable for live-line operation. After welding, a non-reducing-bore live-line tap is installed on the ball valve. A pressure test is then conducted on the sealed cavity formed by the tap, ball valve, and fittings to ensure reliable sealing and avoid leakage risks during subsequent tapping. After passing the pressure test, the non-reducing-bore live-line tap is used to perform a one-time through-hole tap on the main pipeline to ensure the quality of subsequent connections. After tapping is completed and the tool is retracted, the ball valve is closed, and the weld is inspected. Once no leakage is confirmed, the tap and pressure testing device are removed, completing the live-line tapping operation. This example effectively ensures the safety and reliability of the construction process by verifying the cavity's sealing performance after welding and using a non-reducing-bore one-time through-hole tapping. It achieves rapid live-line tapping without interrupting pipeline operation while ensuring operational safety.

[0044] As attached Figure 2 As shown:

[0045] Example 2:

[0046] This invention provides a method for uninterrupted, pressurized, and safe expansion joint construction of PE electrofusion and thermofusion pipes, comprising the following steps:

[0047] S1: Visual-guided assembly and welding;

[0048] S101: Install the saddle-shaped electrofusion fitting assembly with a full-bore ball valve to the target location on the PE main pipeline;

[0049] S102: During installation, a laser contour sensor is used to perform a three-dimensional scan of the contact area between the welding surface of the pipe fitting and the main pipe. The obtained real-time three-dimensional point cloud data is then registered and compared with the pre-stored standard digital model of the pipe fitting welding surface.

[0050] S103: Based on the attitude adjustment guidance output by the comparison results, the component is accurately positioned and then electrofusion welding is performed.

[0051] S2: Adaptive path planning and cavity sealing verification before opening;

[0052] S201: After welding is completed and cooled, keep the ball valve open and install the non-reduced diameter pressurized hole punch with integrated coaxial laser profile sensor onto the ball valve;

[0053] S202: After installation, a sealing pressure test is performed on the sealed cavity consisting of the port opener, the open ball valve, and the pipe fittings.

[0054] S203: After passing the pressure test, the laser profile sensor of the hole opener is used to scan the surface of the main pipe in the area to be opened below through the open ball valve to obtain the actual three-dimensional shape data of the area to be processed.

[0055] S204: The actual three-dimensional topography data is registered with the standard digital model in real time, and the control system automatically calculates and generates an adaptive hole-opening processing path that matches the geometric features of the welding surface of the pipe fitting.

[0056] S3: Adaptive through-hole;

[0057] S301: Based on the generated adaptive processing path, drive the non-reducing diameter pressurized tapper to perform a one-time through-hole opening on the main pipe, and form a 90° through-hole in the direction perpendicular to the pipe axis that penetrates the inner and outer walls of the main pipe.

[0058] S302: During the hole-opening process, the work interface is monitored in real time by an image acquisition device introduced near the welding area, and the work status is analyzed based on image recognition; this step introduces an image acquisition device (such as a high-definition industrial camera or infrared thermal imager) to continuously capture images of the welding and hole-opening areas, and performs real-time image processing and feature analysis on the video stream.

[0059] Feature extraction and comparison: Representative features (such as brightness distribution in the molten area, color gradient, edge contours, etc.) are extracted from each frame of the image to form the feature vector of the current frame. The system has a pre-defined feature library of qualified welding and hole opening conditions, which includes reference feature vectors. .

[0060] Similarity metric: Euclidean distance is used as a feature deviation metric;

[0061]

[0062] when The larger the value, the more significant the difference between the current state and the normal state.

[0063] Normalized similarity score: To facilitate direct judgment of state quality, distance can be converted into a similarity score. :

[0064]

[0065] in This is the maximum permissible distance (based on experimental calibration, corresponding to a completely anomalous state). When When it is close to 1, it indicates that the state is almost the same as normal; when Below the set threshold When this occurs, it is determined to be abnormal and an alarm is triggered.

[0066] Anomaly detection and control: Setting a lower limit for similarity (e.g., 0.85), when When this occurs, it indicates an abnormal operating status, which may be caused by localized overheating, tool wear, or material defects. The system will immediately trigger an audible and visual alarm, and if necessary, automatically pause feed or switch to a safety mode, prompting the operator to intervene and inspect the system, thereby preventing the defect from escalating or causing damage to the main pipeline.

[0067] S4: After the hole is opened and the tool is retracted, close the ball valve, inspect the weld, and remove the non-reduced diameter pressure hole opener and pressure testing device after the inspection is correct to complete the pressure expansion construction.

[0068] 1. In one embodiment of the present invention, the standard digital model in S102 is a benchmark data model constructed by performing high-precision three-dimensional scanning on the welding surface of the saddle-shaped electrofusion pipe fitting and extracting its surface curvature, key contour lines and best fitting plane information.

[0069] 2. In one embodiment of the present invention, the driving mechanism for the hole opener to perform hole opening in S301 is a multi-axis robotic arm. The robotic arm can dynamically adjust the feed speed and cutting depth according to the adaptive machining path and the real-time feedback of the laser contour sensor.

[0070] 3. In one embodiment of the present invention, the image recognition analysis in S302 specifically includes: performing real-time dynamic comparison between the video stream captured by the image acquisition device and a preset qualified welding and opening status feature library; if the feature is found to deviate from the preset threshold, an alarm is triggered.

[0071] Working principle: Based on Example 1, Example 2 further introduces intelligent technologies such as vision-guided assembly, adaptive path planning before opening and cavity sealing verification, real-time feedback control and image recognition monitoring of the operation process, so as to realize the digitalization, precision and traceability of the entire process of pressurized expansion construction.

[0072] Specifically, in stage S1, a laser contour sensor performs a 3D scan of the contact area between the welding surface of the saddle-shaped electrofusion fitting and the PE main pipeline. Real-time point cloud data is registered and compared with a pre-stored standard digital model. Following attitude adjustment guidance, the component is precisely positioned before electrofusion welding, effectively eliminating human positioning errors and ensuring high fit and coaxiality of the weld surface. This standard digital model is constructed based on a high-precision 3D scan of the fitting's welding surface, extracting surface curvature, key contour lines, and the best-fit plane information, providing a reliable benchmark for subsequent matching.

[0073] In stage S2, after welding is completed and cooled, the ball valve is kept open. First, a pressure tap without diameter reduction is installed on the ball valve, and a sealing pressure test is performed on the sealed cavity composed of the tap, ball valve and pipe fitting to eliminate the risk of cavity leakage in advance. Then, a coaxial laser profile sensor is used to perform in-situ three-dimensional scanning of the main pipe surface in the area to be tapped through the open ball valve to obtain actual shape data and register it with the standard digital model. The control system automatically calculates and generates an adaptive tapping processing path that matches the geometric features of the pipe fitting welding surface, which solves the problem that the traditional fixed path cannot adapt to the deviation of the pipe surface.

[0074] In stage S3, based on the adaptive machining path, a multi-axis robotic arm drives a pressure-operated, non-reducing borehole tap to perform a one-time through-hole opening on the main pipe. The robotic arm can dynamically adjust the feed rate and cutting depth based on the path and real-time feedback from the laser contour sensor to ensure opening accuracy. During the opening process, an image acquisition device placed near the welding area monitors the work interface in real time and dynamically compares the video stream with a preset database of qualified welding and opening status features. Once a feature deviates from a preset threshold, an alarm is triggered, enabling immediate warning and intervention for abnormal states.

[0075] In stage S4, after the hole is opened and the tool is retracted, the ball valve is closed, the weld is inspected, and after confirming that there are no problems, the hole opener and pressure testing device are removed to complete the pressurized expansion construction.

[0076] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for uninterrupted, pressurized, and safe expansion of PE electrofusion pipes, characterized in that: Includes the following steps: S1: Visual-guided assembly and welding; S2: Adaptive path planning and cavity sealing verification before opening; S3: Adaptive through-hole; S4: After the hole is opened and the tool is retracted, close the ball valve, inspect the weld, and remove the non-reduced diameter pressure hole opener and pressure testing device after the inspection is correct to complete the pressure expansion construction.

2. The method for uninterrupted pressurized safe expansion of PE electrofusion pipelines according to claim 1, characterized in that, S1 specifically includes: S101: Install the saddle-shaped electrofusion fitting assembly with a full-bore ball valve to the target location on the PE main pipeline; S102: During installation, a laser contour sensor is used to perform a three-dimensional scan of the contact area between the welding surface of the pipe fitting and the main pipe. The obtained real-time three-dimensional point cloud data is then registered and compared with the pre-stored standard digital model of the pipe fitting welding surface. S103: Based on the attitude adjustment guidance output by the comparison results, the component is accurately positioned and then electrofusion welding is performed.

3. The method for uninterrupted pressurized safe expansion of PE electrofusion pipelines according to claim 1, characterized in that, S2 specifically includes: S201: After welding is completed and cooled, keep the ball valve open and install the non-reduced diameter pressurized hole punch with integrated coaxial laser profile sensor onto the ball valve; S202: After installation, a sealing pressure test is performed on the closed cavity consisting of a non-reduced bore pressure tap, an open ball valve, and pipe fittings. S203: After passing the pressure test, the laser profile sensor without a necking pressure tap is used to scan the surface of the main pipe in the area to be tapped below through the open ball valve to obtain the actual three-dimensional topographic data of the area to be processed. S204: The actual three-dimensional topography data is registered with the standard digital model in real time, and the control system automatically calculates and generates an adaptive hole-opening processing path that matches the geometric features of the welding surface of the pipe fitting.

4. The method for uninterrupted pressurized safe expansion of PE electrofusion pipelines according to claim 1, characterized in that, Specifically, S3 includes: S301: Based on the generated adaptive processing path, drive the non-reducing diameter pressurized tapper to perform a one-time through-hole opening on the main pipe, and form a 90° through-hole in the direction perpendicular to the pipe axis that penetrates the inner and outer walls of the main pipe. S302: During the hole-opening process, the working interface is monitored in real time by an image acquisition device introduced near the welding area, and the working status is analyzed based on image recognition.

5. The method for uninterrupted pressurized safe expansion of PE electrofusion pipelines according to claim 2, characterized in that, The standard digital model in S102 is a benchmark data model constructed by performing high-precision three-dimensional scanning on the welding surface of the saddle-shaped electrofusion pipe fitting and extracting its surface curvature, key contour lines and best fitting plane information.

6. The method for uninterrupted pressurized safe expansion of PE electrofusion pipelines according to claim 4, characterized in that, The driving mechanism in S301 that drives the non-reduced diameter pressure tapping device to perform tapping is a multi-axis robotic arm. This multi-axis robotic arm can dynamically adjust the feed speed and cutting depth according to the adaptive machining path and the real-time feedback from the laser contour sensor.

7. The method for uninterrupted pressurized safe expansion of PE electrofusion pipelines according to claim 4, characterized in that, The image recognition analysis in S302 specifically includes: comparing the video stream captured by the image acquisition device with a preset qualified welding and opening status feature library in real time; if the feature is found to deviate from the preset threshold, an alarm is triggered.

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