The core principle of the maintenance cycle for pressure-sealing equipment Pressure-sealing technology is a core technology in numerous fields such as petroleum, chemical industry, natural gas, and urban gas pipelines. It enables precise sealing and emergency repair of leakage points or modified pipeline sections without interrupting the pipeline operation or stopping the equipment. Just like any sophisticated equipment, the long-term reliability and lifespan of pressure-sealing equipment are largely dependent on a scientific and rigorous maintenance system. Ignoring maintenance may cause even the most advanced technology to fail at critical moments; while adhering to preventive maintenance can extend the equipment's performance and value by several times. This article will comprehensively and systematically explain from multiple dimensions such as maintenance cycle, daily maintenance, deep maintenance, seal component management, special condition handling, and scientific storage, how often the pressure-sealing equipment needs to be maintained and how to establish a scientific and reasonable equipment maintenance system. I. Core Principles of Maintenance Cycle for Pressure-Resistant Sealing Equipment If pressure-sealing is likened to a precise "pipe surgery", then the sealing equipment is the "core instrument" on the operating table. These devices are constantly exposed to harsh conditions such as high pressure, corrosion and heavy loads. Any minor malfunction could lead to a major accident during operation.c(1) Maintenance cycle at the equipment level: Six months and thirty times - the "golden rule" In the field of pressure sealing and blocking, whether it is experienced technicians or relevant technical specifications, for the deep maintenance cycle of the main sealing equipment (such as pressure opening machines, sealing devices, hydraulic cylinders, etc.), a commonly accepted golden rule is generally followed - after every 30 operations or every 6 months, regardless of whether the equipment shows obvious problems or fault signs, a comprehensive disassembly inspection and deep maintenance must be carried out. How was this cycle established? From the perspective of mechanical motion, the precision parts inside the pressure-bearing opening machine and the sealing device, such as gears, bearings, and screws, are subjected to a large amount of alternating loads and wear during the continuous high-pressure and rotational cutting process. Every 30 operations, the cumulative wear of the internal parts, the consumption of lubricating oil, and the fatigue trend of the components usually reach the threshold that requires manual intervention. From the temporal dimension, even if the equipment is idle for half a year, the seals will still face the risk of natural aging (oxidation, hardening), and the metal parts may also develop minor rust due to an unsuitable storage environment. Therefore, the 6-month time point also constitutes a necessary boundary for active intervention. This "dual-control principle of fixed cycle and fixed frequency" maximizes the transformation of passive maintenance into proactive governance, ensuring that the equipment always operates at the optimal state of mechanical accuracy and sealing performance. It enables the equipment to "be summoned when needed, be capable of fighting when arrived, and be able to win when engaged in combat" at critical moments. (2) Inspection cycle at the sub-division level: Daily defense lines before and after the operation In addition to the deep maintenance carried out in units of "month" or "30 times", the maintenance cycle of the pressure-sealing equipment should be further refined to "day" or even "shift". The key to maintaining pressure operation equipment lies in "frequent inspection and regular maintenance". Many production units require that a comprehensive routine inspection be conducted before each operation begins and after it ends. The pre-operation inspection focuses on verifying the integrity of the equipment's appearance, checking for any leakage in the hydraulic pipelines, ensuring the flexibility of the blowout preventer, and inspecting for any abnormal wear on the slips; the post-operation inspection, on the other hand, concentrates on the cleanliness of the equipment's interior. This frequent daily maintenance actually forms the first line of defense against faults and is the lowest-cost and most effective strategy for extending the equipment's lifespan. (3) "Compulsory Maintenance" Period after Special Operating Conditions After certain specific extreme conditions are over, the maintenance cycle of the equipment needs to be significantly shortened, or even "operation as maintenance" needs to be carried out immediately. When the pressurized sealing equipment has handled high-temperature media (such as steam or heat transfer oil pipelines with temperatures exceeding 200℃), or has come into contact with highly corrosive media (such as acidic gases, sulfur-containing wastewater, ammonia water, etc.), even if the equipment has only completed one operation, the replacement of the sealing elements must be included in the mandatory maintenance plan. Otherwise, there is a high possibility of a major accident of seal failure during the next use. II. Core elements of maintenance: cleaning, lubrication, tightening, and adjustment In order to have a more intuitive understanding of what tasks need to be carried out during the maintenance period of the pressure-sealing equipment, the essence of maintenance can be summarized as the four key elements: cleaning, lubrication, tightening, and adjustment. (1) Cleaning: Preventing contaminants from entering Cleaning is the foundation of maintenance. After each operation, the oil stains, dirt, residual media, and metal shavings produced during cutting must be thoroughly cleaned from the surface of the equipment immediately. Especially the sealing surfaces between the plug and the pipeline, the driving rod of the opening machine, the exposed parts of the hydraulic piston rod, and the threaded grooves on the feed screw are all areas prone to accumulate contaminants and have a significant impact on the equipment's accuracy. If not cleaned in time, the remaining sealant will solidify and cause components to get stuck, while the metal shavings will directly scratch the precise sealing surfaces. (2) Lubrication: Ensure smooth operation of the core components Lubrication is the lifeblood of equipment. In a pressure-sealing system, any metal components that undergo relative motion or contact - including the cylinder diameter of the high-pressure cylinder, the rack and pinion, the threads of the tightening bolts, the feed screw, the bearings at each hinge point, and the internal gears of the gearbox - all require the addition of lubricating grease or hydraulic oil at appropriate intervals. The hydraulic system itself should also have its hydraulic oil and filters replaced regularly to ensure that the cleanliness and viscosity of the oil meet the requirements of the working conditions. (3) Tightening and Adjustment: Restore Geometric Accuracy After undergoing multiple high-pressure compressions and reciprocating movements, there is a possibility that the fasteners such as bolts and nuts may become loose. The alignment of the coupling, the stroke limit of the piston rod, and other related interlocking relationships may also experience slight drift. If these parameters deviate from the factory standards, it will directly affect the alignment accuracy of the sealing device, potentially leading to poor sealing or uneven wear. Therefore, it is necessary to calibrate the torque of the key fasteners through semi-annual maintenance or mandatory maintenance of thirty times, and adjust the limit positions and strokes according to the standard specifications to maintain the precision of the equipment. III. "Rotation System" Management of Seals: Seal Lifespan In pressure-sealing equipment, the sealing components are the "key elements" that determine the success or failure of the sealing process. They are also the most fragile and the ones that require the most frequent replacements. (1) The different service lifetimes of static seals and dynamic seals The service life of the sealing system is closely related to the specific working conditions and usage frequency. Under the condition of not replacing the sealing material and with suitable working conditions, the moving sealing part of the sealing system can remain in normal use for more than 3 months at a time; the static sealing part, as it does not bear continuous sliding friction, can remain in normal use for more than 1 year at a time. However, in the actual scenarios of pressure-sealing operations, the working conditions of the sealing components are much more severe and unpredictable than those of normal pipeline operations. As the sealing device advances, seats, and releases pressure in the high-pressure pipeline, the sealing elements need to undergo multiple intense pressure fluctuations from normal pressure to working pressure, and then from working pressure back to normal pressure for release.