Pressure-sealing Maintenance Comprehensive Analysis: A Professional Guide from Preparatory Work to Operation MonitoringA minor oversight may lead to irreversible consequences. Every step in pressure sealing and maintenance is crucial for the safety of both life and property. In the field of industrial pipeline maintenance, the pressure-sealing technology, as a specialized operation, can complete tasks such as pipeline replacement, relocation, valve replacement, and adding branch lines while the pipeline medium is continuously flowing. It can also be used for rapid emergency repairs when the pipeline leaks. This technology is safe and reliable, pollution-free. It does not interfere with the normal transportation of the pipeline, and can ensure the completion of the connection between the old and new pipelines in a safe, efficient and environmentally friendly manner. With the advancement of technology, the complexity of pressure-sealing maintenance requires practitioners to have a thorough understanding of the technical details and safety requirements at each stage. 01 Preparation for Work: Establishing the Foundation for Safe Construction The preparatory work before pressure sealing operations is the foundation for ensuring the safe and smooth progress of the entire project. This stage involves multiple aspects such as on-site assessment, plan formulation, and personnel allocation. Any oversight could lead to serious consequences. On-site investigation and risk assessment are the first and most crucial steps in the preparation for the operation. According to the relevant guidelines issued by the Emergency Management Department of Shandong Province, enterprises need to accurately identify the safety risks associated with pressure-sealed operations and formulate and implement corresponding control measures. Especially in the fields of chemical engineering and hazardous chemicals, pressure-bearing sealing operations are unconventional construction tasks aimed at effectively sealing fluid medium leaks. The on-site conditions are complex, the operation conditions are unstable, and the safety risks are high. The formulation and approval of the construction plan are equally crucial. According to the requirements of GB/T 28055-2023 "Technical Specifications for Pressure Sealing of Steel Pipelines", before the construction, a welding process instruction manual needs to be compiled based on the pipeline material, operating parameters, and welder material. After welding in accordance with the welding process guide, a welding process assessment is conducted. Based on the qualified welding process assessment, a welding process procedure is compiled. This series of standardized procedures ensures the standardization and reliability of the operation. In terms of personnel preparation, pressure-sealing operations should be carried out by experienced technicians. According to relevant safety precautions, pressure welding work should be performed by experienced and skilled welders. Generally speaking, it is not advisable to conduct pressure-bearing welding tests on pipelines and containers in the production and operation process. Instead, one should first practice repeatedly on test pieces to basically master the operation methods and accumulate certain experience, and then carry out the actual operation. 02 Equipment Maintenance: Ensuring the Reliability of Sealing Equipment The maintenance quality of the sealing equipment directly affects the success or failure of the pressure-sealing operation. Well-maintained equipment can operate stably in high-temperature and high-pressure, flammable and explosive environments, reducing the possibility of accidents. Daily cleaning and maintenance form the basis of equipment maintenance. According to the relevant maintenance requirements, the sealing head should be thoroughly cleaned after each use. Key components such as the connecting fork pin shaft should be lubricated with appropriate lubricating oil to prevent rust and ensure flexibility. For the sealing cover of the housing, the provided sealing gasket, steel cover plate and sealing flange port should be used to protect the surface of the flange. When the equipment is not in use, keep the cover plate covering the housing. Professional storage and handling cannot be ignored either. During on-site loading and unloading operations, the vulnerable components such as the vent valve and the short section should be removed. The handling of the machine must be extremely careful. Rough handling can cause damage and result in costly repairs. All rules must be followed and shortcuts must be avoided. If the head is not fully retracted before installation and disassembly, the sealing elements are very likely to be damaged. Strictly prohibiting non-standard modifications is an important principle in equipment maintenance. The relevant regulations clearly state that it is not allowed to weld lifting devices, platforms, etc. on the outer shell of the sealing head. Heat causes the shell to deform and hinders normal operation. Such improper operation will alter the equipment's stress characteristics, and in a high-pressure environment, it may lead to catastrophic consequences. 03 Work Process: Precisely Control Construction Phases The pressure sealing operation process involves a series of precise steps, and each step must be carried out strictly in accordance with the regulations. From the excavation of the operation pit to the removal of the seal, the entire process requires the operators to possess professional knowledge, a rigorous attitude, and rich experience. The excavation and sealing operation pit is the first crucial step. During the excavation process, the construction team leader should uniformly direct the excavators, and other personnel should stay away from the site. To prevent slope failure during the excavation operation, a certain slope must be provided around the pit. In case of slope failure, it is necessary to immediately organize the cleanup. Pressure-sealing welding of the three-way joint is one of the most demanding sections in terms of technical requirements. During the welding process, welders must wear protective equipment to prevent eye injuries from arc light. If there is a weld-through phenomenon, it should be immediately blocked with a welding rod and welded firmly; if there is a fire hazard, the emergency plan should be activated immediately. According to relevant safety regulations, the welder performing pressure-bearing repair operations should choose a position that avoids the risk of pressure medium spewing out, and try to perform the repair from the upwind side or use a baffle to separate the pressure medium. The sealing operation process must strictly follow certain principles. During the sealing process, it should be carried out in accordance with the principle of "high pressure first, then low pressure; inner side first, then outer side", that is, the high-pressure end should be sealed first, and then the low-pressure end.