1. Valve Aging Mechanism and Failure Risk
- Valves in a Gasoline Storage Tank are constantly exposed to gasoline vapor and moisture, leading to seal aging, stem corrosion, and internal carbon buildup.
- Sulfides and chlorides in gasoline accelerate electrochemical corrosion of metal components.
- Frequent operation causes mechanical wear, and temperature fluctuations make rubber seals lose elasticity, resulting in micro‑leakage.
- Undetected micro‑leaks may develop into major leaks, threatening safe operation of the tank.
2. Necessity of Regular Inspection and Assessment Principles
- Valves do not require mandatory replacement at fixed intervals, but a condition‑based assessment mechanism is essential.
- Monthly visual inspections check for leaks, corrosion, or sluggish operation; a comprehensive annual inspection includes sealing tests and stem flexibility verification.
- If packing loosening, spring fatigue, or valve body deformation is found, replace the valve immediately rather than waiting for complete failure.
- This ensures proactive risk control and prevents catastrophic incidents.
3. Industry Standards and Maintenance Basis
- According to SY/T 5225‑2019, safety accessories for storage tanks must be calibrated annually, with increased frequency in low‑temperature environments.
- GB 50074‑2014 requires valves to be easy to operate and maintain, with key components replaceable.
- International standards like API 650 emphasize "continuous monitoring and timely intervention" as the core of safety, aligning with domestic practices.
- Regularly reviewing these standards ensures compliance and optimal maintenance strategies.
4. Actual Maintenance Operations and Practical Experience
- Valve replacement is often combined with annual maintenance or process switching in oil depots (e.g., Xujiawan oil depot repacked fire‑fighting valves with graphite material).
- During oil product switching (e.g., Lanzhou‑Chengdu‑Chongqing pipeline), switching valves are replaced simultaneously to reduce contamination risk.
- Before operation, shut off the process and release pressure; use specialized tools to avoid flange damage.
- After replacement, perform pressure testing and opening/closing verification to ensure system safety and reliability.