The general procedure of valve maintenance is a systematic and meticulous process to ensure that the valve can return to normal operation and meet the requirements of safety and reliability. The following are the general procedures for valve maintenance according to multiple sources: 

 I. Preliminary preparation 

 1. Safety preparation: 

 Ensure the safety of the operating environment, turn off the corresponding fluid system, release pressure, and take necessary safety measures, such as wearing protective equipment. 

 Cut off the power supply, gas source and hydraulic oil line associated with the maintenance valve, and clean the gas line, oil line and components to ensure that it meets the safety operation regulations. 

 2. Preparation of tools and materials: 

 Prepare the necessary repair tools and materials, such as wrenches, screwdrivers, gaskets, sealants, cleaning agents, etc., and ensure the quality and suitability of these tools and materials. 

 3. Program formulation: 

 For large-diameter valves or important valves, maintenance plans should be prepared, maintenance processes should be formulated, and approved by relevant departments. 

II. Fault observation and preliminary inspection 

 1. Phenomenon observation: 

 Observe the abnormal situation of the valve in the process of opening, closing or adjusting, such as leakage, jamming, vibration, etc. 

 2. Preliminary inspection: 

 Check whether the appearance, sealing surface, connection parts, etc. of the valve are damaged, worn or loose. 

 Check whether the operating mechanism of the valve is flexible and the indication is accurate. 

III. Selection of professional diagnosis and repair methods 

 1. Professional diagnosis: 

 If the preliminary inspection fails to find the cause of the failure, a professional diagnosis is required. Use professional testing tools and equipment to conduct more in-depth testing and analysis of the valve to determine the specific cause and location of the failure. 

 2. Choose the appropriate repair method: 

 Choose the appropriate repair method according to the troubleshooting results. Common repair methods include replacing damaged parts, repairing the sealing surface, adjusting the operating mechanism, etc. 

 IV. Disassembly and repair 

 1. Disassemble the valve: 

 Remove the relevant parts of the valve according to the maintenance needs. During the disassembly process, pay attention to record the location and order of each part for subsequent assembly. 

 2. Cleaning and inspection: 

 Use appropriate cleaning agents and tools to remove impurities and dirt inside the valve to ensure that the valve is clean and unobstructed. 

 Check the sealing surface and operating mechanism of the valve to make sure that it is intact. 

 3. Repair or replace parts: 

 Repair or replace damaged or worn parts based on troubleshooting results. Use appropriate tools and materials to repair or replace according to the manufacturer's requirements. 

 V. Assembly and testing 

 1. Reassemble the valve: 

 Reassemble the valve according to the position and order recorded at the time of disassembly. Make sure that each part is installed correctly and tightly connected. 

 2. Manual operation test: 

 After the assembly is completed, the manual operation test is carried out first. Manually switch the valve to check whether its operation is flexible and the instructions are accurate. 

 3. Sealing test: 

 Close the valve and observe whether there is a leak at the junction of the valve and the pipe. If a leak is found, the cause should be found in time and corresponding remedial measures should be taken. 

 4. Functional test: 

 Carry out functional tests on the basis of ensuring that the valve is well sealed. According to the process of the system, simulate the actual operating conditions and test whether the switching performance and adjustment performance of the valve meet the requirements. 

VI. Record and Archive 

 1. Record the repair data: 

 During the repair process, the repair data should be recorded in detail, including troubleshooting results, repair methods, replacement parts, etc. These data are of great significance for subsequent troubleshooting and maintenance. 

 2. Archive and repair report: 

 After the repair is completed, the repair report should be prepared and submitted to the user unit for archiving. The repair report should include the maintenance process, replaced parts, test results and other information. 

VII. Precautions 

 1. The maintenance valve should be marked with the maintenance number, working pressure, working temperature and medium. 

 2. Disassembly and assembly should be carried out according to the process procedures, and special tools and tools should be used. Forcibly disassembly and installation are strictly prohibited. 

 3. Disassembled valves should be stacked separately, and those with direction and location requirements should be checked or marked. 

 4. Cleaning and descaling should be thorough to ensure that there are no impurities and dirt inside the valve. 

 5. When assembling, it should be ensured that each component is installed correctly, tightly connected, and there is no leakage. Through the above steps, we can ensure the smooth maintenance of the valve and restore the normal operation of the valve.