Valve as an important part of fluid control system, its performance directly affects the safety and reliability of the system. In order to ensure the long-term stable operation of the valve and extend its service life, regular maintenance and maintenance are essential. The following are several key steps and precautions for valve maintenance:
1. Check regularly
Appearance inspection: Check the appearance of the valve regularly to see if there is crack, corrosion, rust or leakage. Especially the valve body, valve cover, flange joints and other parts.
Sealing performance check: Check the sealing performance of the valve to ensure that there is no leakage when the valve is closed. For valves in critical parts, the leakage test can be carried out with the detection instrument.
Operation flexibility check: Regularly operate the valve to ensure that the valve stem, hand wheel or actuator can rotate flexibly without stuck phenomenon.
2. Clean the valve
Remove debris: Regularly clean the inside and outside of the valve to prevent dust, dirt, welding slag and other debris accumulation, affecting the sealing performance of the valve or operational flexibility.
Cleaning medium residue: For the transport of viscous medium or easily crystallized medium of the valve, should be cleaned regularly to prevent the medium residue caused by valve blockage or stuck.
3. Lubrication maintenance
Valve stem lubrication: The valve stem is a key part of the valve operation, and the appropriate amount of grease or lubricating oil is applied regularly to prevent the valve stem from rust or stuck. For high or low temperature environments, high or low temperature resistant lubricants should be selected.
Transmission parts lubrication: For gearbox, worm gear and other transmission parts, should be regularly checked lubrication to ensure smooth operation.
Seal lubrication: Some valve seals (such as O-rings, fillers) also need regular lubrication to maintain their elasticity and sealing performance.
4. Check fasteners
Bolt and nut check: Periodically check whether the bolts and nuts at the joint of the valve flange are loose, and tighten them if necessary. For high pressure or high temperature valves, loose fasteners can lead to leaks or accidents.
Valve cover bolt check: Check the tightness of valve cover bolt to ensure the tightness between valve cover and valve body.
5. Maintenance of seals
Packing seal inspection: For valves with packing seals (such as gate valves, globe valves), regularly check the wear of the packing. If the packing is aged or worn, it should be replaced in time to prevent leakage.
Soft seal inspection: For valves with soft seals (such as rubber, teflon), check whether the seals are aging, deformed or damaged, and replace them if necessary.
6. Anti-corrosion treatment
Surface corrosion protection: For valves exposed to damp or corrosive environments, regularly check whether the surface corrosion protection coating is intact. If the coating falls off or is damaged, paint should be repainted or other anti-corrosion measures should be taken in time.
Internal corrosion prevention: For the valve conveying corrosive media, the corrosion inside the valve should be checked regularly, and the valve of corrosion-resistant material should be replaced if necessary.
7. Prevent freezing
Insulation measures: In a low temperature environment, the valve may not operate normally due to freezing of the medium. Valves and pipes should be insulated to prevent freezing.
Empty the medium: for valves that are not used for a long time, especially in low temperature environments, the medium in the valve and pipeline should be emptied to prevent freezing damage.
8. Operate regularly
Prevent stuck: For the valve that is in the open or closed state for a long time, the switch operation should be carried out regularly to prevent the stem, valve disc or seal from being stuck because of long-term immobilization.
Check the actuator: For electric, pneumatic or hydraulic driven valves, regularly check the working status of the actuator to ensure its normal operation.
9. Keep track of maintenance
Establish maintenance records: record the time, content, problems found and measures for each maintenance, so as to facilitate follow-up and management.
Develop a maintenance plan: according to the frequency of use and working environment of the valve, develop a reasonable maintenance plan to ensure that the valve is maintained in time.
10. Replace wearing parts
Regular replacement: Valve seals, packing, stem, etc. are vulnerable parts, should be replaced regularly according to the use situation, to avoid valve failure due to aging parts.
Spare parts management: Stock commonly used wearing parts to ensure timely replacement when needed to reduce downtime.
11. Maintenance of special valves
Safety valve: Regularly check the take-off pressure and sealing performance of the safety valve to ensure that it can work normally in an emergency.
Check valve: Check whether the disc of the check valve is flexible to prevent the backflow of the media due to stagnation.
Regulating valve: Periodically calibrate the positioner and actuator of the regulating valve to ensure its adjustment accuracy.
Conclusion
Valve maintenance is the key to ensure its long-term stable operation. Through regular inspection, cleaning, lubrication, fastening and replacement of wearing parts, you can effectively extend the service life of the valve, reduce the occurrence of failures, and ensure the safety and reliability of the system. At the same time, the establishment of sound maintenance records and plans helps to improve the scientific and efficient management of valves.
