Ball valves, widely used in industries such as oil, chemical processing, power generation, and water treatment, are valued for their excellent sealing performance, ease of operation, and long service life. To ensure their stable operation and extend their lifespan, regular maintenance is essential. Below are the key issues to focus on when maintaining ball valves:
1. Cleaning and Inspection
External Cleaning
- Regularly clean the valve's exterior, especially the handwheel and stem, to prevent the accumulation of dirt, dust, or grease that could lead to corrosion or jamming.
Internal Cleaning
- If the valve has not been used for a long time or operates sluggishly, disassemble it to clean the internal ball and sealing surfaces.
- Avoid using sharp tools during cleaning to prevent scratches on the sealing surface.
Debris Inspection
- Check for debris (e.g., welding slag, metal fragments) in the pipeline, as these can scratch the sealing surface and compromise the sealing performance.
2. Lubrication Maintenance
Lubrication Points
- For ball valves with a stem lubrication structure, periodically inject lubricant into the stem to reduce friction and prevent seizing.
Lubricant Selection
- Use lubricants compatible with the working medium that resist decomposition.
- In high-temperature or corrosive environments, select specialized high-temperature and corrosion-resistant lubricants.
Frequency
- Adjust lubrication frequency based on operating conditions and usage rates, with quarterly or semi-annual checks recommended.
3. Sealing Component Maintenance
Sealing Surface Inspection
- Regularly check the sealing surface for scratches, dents, or deformation. If damaged, promptly repair or replace it.
Seal Ring Aging
- Materials like rubber or PTFE may age, harden, or crack over time. Inspect and replace them regularly.
Proper Installation
- When replacing seals, ensure they are installed correctly to avoid uneven force that may cause leakage.
4. Operation Component Inspection
Stem Flexibility
- Check whether the stem operates smoothly and inspect for rust or bending. Apply lubrication or make corrections if issues are found.
Handles and Actuators
- Inspect handles, gearboxes, or actuators for secure connections and check for wear or loosening.
Limit Devices
- For valves with limit devices, check that the limit bolts are tight and properly positioned to ensure the valve opens and closes correctly.
5. Anti-Corrosion and Environmental Protection
Surface Corrosion Prevention
- Apply anti-corrosion treatments such as repainting or coating to prevent rust on metal-bodied valves.
Storage Environment
- Store unused or spare valves in a dry and ventilated area to prevent internal corrosion or seal aging due to moisture.
6. Leak Detection
Online Inspection
- Regularly inspect operating valves for media leaks. Check sealing surfaces, stem packing, and flange connections for any signs of leakage.
Pressure Testing
- After reinstallation or maintenance, perform water or air pressure tests to ensure there are no leaks before putting the valve back into service.
7. Preventing Misoperation
Locking Devices
- For ball valves with locking mechanisms, periodically check that the locks function properly to prevent accidental operations leading to media loss or accidents.
Clear Markings
- Ensure the valve's open/close markings are clear for operators to quickly determine its status.
8. Special Considerations in High-Temperature or Corrosive Environments
High-Temperature Materials
- In high-temperature environments, monitor internal components for deformation due to thermal expansion or aging. Pay special attention to the high-temperature resistance of seals.
Corrosive Media Protection
- For corrosive media, use valves made of corrosion-resistant materials and regularly inspect for signs of corrosion.
9. Regular Training and Record Keeping
Operator Training
- Ensure operators are trained in the correct usage of ball valves, including proper opening/closing sequences and torque application, to avoid accidental damage.
Maintenance Logs
- Maintain detailed logs of all cleaning, lubrication, repairs, or part replacements to facilitate timely identification and resolution of potential issues.
Summary
Maintaining ball valves involves multiple aspects, such as cleaning, lubrication, seal maintenance, and operation checks. The focus areas of maintenance may vary depending on the operating environment, so it’s crucial to develop a tailored maintenance plan based on actual conditions. Regular inspections and upkeep not only enhance the valve’s lifespan but also minimize operational failures, improving overall equipment efficiency.
