Marine valves, as important control components in ship piping systems, may experience various malfunctions during actual use. The following introduces common types of malfunctions and their solutions:
Common Types Of Faults
Leakage fault
Internal leakage: When the valve is in the closed state, the medium leaks between the valve disc and the valve seat, usually due to damage to the sealing surface of the sealing pair, foreign object adhesion, or spring failure. For example, factors such as the presence of hard particles in the medium, improper valve operation, or long-term wear may cause damage to the sealing surface of the sealing pair; Insufficient cleanliness of the medium and inadequate cleaning during installation may cause foreign objects to adhere; Factors such as fatigue, corrosion, or overload may cause the spring to fail.
External leakage: The medium leaks from the valve body, valve cover, packing box, and other parts, mainly due to aging gaskets, loose connecting bolts, or cracks in the valve body. The sealing gasket will age under long-term pressure, high temperature, or corrosive media; Casting defects, stress concentration, or external impact may cause cracks in the valve body.
Jamming fault
The main reasons why valves cannot be opened or closed normally include valve stem corrosion, foreign object jamming, poor lubrication, or actuator failure. Valve stem corrosion may be caused by strong corrosiveness of the medium and inadequate protective measures; Impurities in the medium and inadequate cleaning during installation may cause foreign objects to get stuck; Improper selection of lubricating oil, failure of lubricating grease, or blockage of lubrication points can cause poor lubrication; Electrical faults, mechanical faults, or control system failures may cause actuator failures.
Corrosion failure
Marine valves work in corrosive media such as seawater and oil for a long time, mainly manifested as pitting corrosion, crevice corrosion or stress corrosion cracking of valve body, valve cover and other components, ultimately leading to a decrease in valve strength, leakage or blockage. The main reasons include corrosion of media such as seawater and oil, electrochemical corrosion, stress corrosion, etc.
Wear fault
It mainly occurs on components such as valve discs and seats that come into frequent contact, which can lead to a decrease in valve sealing performance and even cause leakage accidents in severe cases.
Other faults
Marine valves may also experience other malfunctions such as actuator failure and valve body rupture, which can pose a threat to the safe navigation of the vessel. The specific reasons need to be analyzed based on the actual situation.
Processing Method
Regarding leakage faults
Internal leakage handling: can be reopened or closed by improving the operation; Disassemble the valve and re grind the valve core and seat sealing surface; Adjust the clearance between the valve core and valve stem or replace the valve disc; Disassemble the valve to eliminate jamming; Replace or weld the sealing ring again.
External leakage treatment: tighten the bolts again or make the gap between the door cover flange consistent; Replace the gasket; Disassemble and repair the sealing surface of the door cover; Adjust the valve installation and stem structure to make it tighter; Replace materials and select valves that meet the requirements; Reduce the extension length of the valve stem, etc.
Regarding card blockage faults
Regularly inspect and maintain valves, and replace valves that are aging or severely worn; Replace loose or damaged valve components; Protect the valve stem to prevent corrosion; Clean up foreign objects inside the valve; Choose the appropriate lubricating oil to ensure good lubrication; Identify and repair faults in the execution mechanism.
Regarding corrosion faults
Preventive measures can be taken by using anti-corrosion coatings and selecting corrosion-resistant materials to manufacture valves; For valves that have already corroded, repair or replace components according to the degree of corrosion.
Regarding wear and tear faults
Conduct regular inspections and maintenance, monitor wear and tear; Change the operating mode to alleviate wear and tear; When the wear seriously affects the performance of the valve, replace the worn parts.
Regarding other malfunctions
Analyze and handle specific fault situations, such as troubleshooting and repairing electrical, mechanical, or control system issues for actuator failures; For valve body rupture, it is usually necessary to replace the valve body.
