Pressure-sealing technology: The key solution for non-stop pipeline maintenance in modern timesI. Introduction: The Technological Revolution in Pipeline Maintenance Field In the modern energy transmission and industrial production system, the pipeline network is like the vascular system of the human body, undertaking the task of transporting important media such as oil, natural gas, chemical raw materials, water supply and heating. Once these pipelines leak or need to be renovated, the traditional solutions often require the cessation of transportation and the emptying of the pipelines, which not only causes huge economic losses but also may affect downstream production and public supply. The emergence of pressure-sealing technology has completely changed this situation and has become a revolutionary technology in the modern pipeline maintenance field. Pressure-sealing, also known as non-stop pipeline sealing or online sealing, is a cutting-edge technology used for repairing, modifying, or branching connections of pipelines while the pipeline medium is continuously flowing and the pressure remains constant. This technology has evolved since the mid-20th century and has developed a complete technical system and operating procedures, becoming an indispensable key technology in pipeline operation and maintenance. II. Basic Principles and Classification of Pressure-Resistant Sealing Technology Basic principleThe core principle of the pressure-sealing technology is to install sealing devices on the outer wall of the pipeline using specialized equipment without interrupting the medium flow in the pipeline. This enables the isolation of a specific section of the pipeline. The entire process maintains the integrity and continuity of the pipeline system, ensuring that the medium flow is not affected. The technical implementation mainly relies on the following key steps: Pressure balance principle: During the process of opening holes and sealing, a pressure balance device is used to ensure that the internal and external pressures at the operation point are equal, preventing the leakage of the medium. 2. Mechanical Sealing Technology: Utilizing special sealing materials and multi-stage sealing structures, it ensures reliable sealing under pipeline pressure. 3. Safety Control System: Through multiple safety valves, pressure monitoring, and emergency shut-off devices, the operation process is guaranteed to be absolutely safe. Technical Classification Depending on the different sealing methods and application scenarios, the pressure-bearing sealing technology can be mainly classified into the following categories: Cavity-type sealing technology By using expandable rubber capsules, the pressure is applied to cause the capsules to expand and form a tight seal with the inner wall of the pipeline. This method is suitable for temporary sealing under medium and low pressure and at normal temperatures, and is simple and quick to operate. 2. Grating-type blocking technology Using a metal baffle mechanical device, the baffle is sent into the pipeline through hydraulic or mechanical means and fixed to create a physical isolation. It is suitable for high-pressure, high-temperature and large-diameter pipeline environments. 3. Foldable Sealing Technology The sealing head is designed with a foldable feature. It is inserted through the pipe opening and, upon reaching the designated position, unfolds to form a seal. It is particularly suitable for environments with limited space or those that are difficult to operate. 4. Composite Sealing Technology Combining the advantages of various sealing methods, a multi-level sealing structure is adopted, which is suitable for extreme working conditions or pipelines with special media. 5. Intelligent Sealing System Integrating sensors, real-time monitoring and automatic control functions, it enables remote monitoring of the sealing status and automatic adjustment, representing the technological development direction. III. Key technical equipment for pressure sealing and plugging Drilling equipment system The perforation equipment forms the basis of pressure sealing operations and mainly consists of: Hydraulic Hole Puncher: Utilizing hydraulic power, it is equipped with a specially designed hole-punching tool, enabling precise hole drilling operations under pipeline operation conditions. Modern hydraulic hole punchers usually come with pressure balance chambers, chip collection systems, and safety interlock devices. Connection valve: As the interface between the opening equipment and the pipeline, it adopts a full-diameter design to ensure that the opening cutter can pass through smoothly without affecting the flow of the medium. Pressure control device: It consists of a balance valve, a pressure relief valve and a pressure gauge system, ensuring that the pressure remains under control throughout the operation process. Blockade equipment system Main body of the plug: Designed based on pipeline parameters and medium characteristics, it includes sealing elements, supporting structures and actuating mechanisms. The high-end plug adopts a modular design, which can adapt to different pipe diameters and pressure ratings. Power system: Provides the power required for the actuation of the occluder. It is divided into three types: hydraulic drive, pneumatic drive, and manual operation. The hydraulic drive system is the most widely used due to its stable output and strong controllability. Control system: It includes the local control console and the remote monitoring system, which can display the sealing position, sealing pressure and equipment status in real time. Some advanced systems have achieved automated operations. Supporting equipment and tools Pipeline measurement equipment: Used for precisely measuring the wall thickness, ellipticity and defect conditions of pipelines, providing data support for the formulation of sealing solutions. Welding equipment: Used for installing blocking elbows and related pipe fittings, it must have the capability for in-service welding to ensure that the welding process does not affect the safety of the pipeline. Testing equipment: Includes endoscopes, ultrasonic detectors and sealing performance testing devices, which are used to assess the condition of the pipeline before and after the operation.