Marine cylinders may generate noise during long-term operation. Noise not only affects the working environment of the ship, but may also be a signal of a fault in the hydraulic system. The reasons for noise in the hydraulic system are relatively complex, and are usually related to factors such as the design and installation of the cylinder, the quality of the hydraulic oil, and the configuration of the pipeline. For the noise problem of marine cylinders, effective diagnosis and reasonable solutions are needed to reduce noise and ensure the normal operation of the system.

1. Common causes of noise in marine cylinders
Bubbles and air enter the hydraulic system
Cause: If there is air or bubbles in the hydraulic system, the compressibility of the hydraulic oil will increase, affecting the action of the cylinder, causing unstable movement and noise. Common reasons for air entering the system include hydraulic oil contamination, cylinder seal damage, pipeline leakage, etc.
Performance: The cylinder vibrates and shakes during the extension and retraction process, and the work is not stable, accompanied by a "buzzing" or "whistling" sound.

Hydraulic oil quality problem
Cause: Hydraulic oil contamination, oil aging, oil quality not meeting the requirements, etc., may cause the hydraulic system to be unstable and generate noise. If there are impurities or moisture in the oil, it will also affect the fluidity of the oil and increase the friction of the hydraulic system.
Symptoms: The noise increases, especially when the cylinder is rapidly extended or retracted or bears a heavy load, the noise is more obvious.

Unstable hydraulic system pressure
Cause: System pressure fluctuations or too high or too low pressure settings will cause the cylinder to work unsteadily and produce abnormal noise. Failure or improper adjustment of components such as overflow valves, control valves, and pressure valves will affect pressure stability.
Performance: "Buzzing" or "hissing" will appear in the system, and the pressure gauge may fluctuate.

Cylinder internal wear or seal damage
Cause: If the piston, piston rod, seal and other components inside the cylinder are worn, aged, damaged, etc., the cylinder will move unsteadily, increase friction, and thus generate noise.
Performance: There are irregular collision or friction sounds when the cylinder is working, especially when the load is large, the noise will be more obvious.

Improper pipeline layout or pipeline bending
Cause: If the layout of the hydraulic pipeline is unreasonable, the pipeline is bent too much or the bending radius is too small, it will increase the resistance to liquid flow, resulting in unstable flow rate, resulting in cavitation, and then noise.
Performance: There are bubbles, vibrations or "clicking" sounds in the hydraulic pipeline.

Improper installation of the cylinder
Reason: If the hydraulic cylinder manufacturer does not align correctly, fix it loosely or there is an eccentric load during installation, it will also affect the normal operation of the cylinder, causing vibration and noise.
Performance: The cylinder is not stable during the extension and retraction process, and produces abnormal noise or vibration.

Poor design of the oil return system
Reason: Improper design of the oil return system, unreasonable position of the oil return port of the cylinder or blockage of the pipeline will lead to poor oil flow, unstable flow and noise.
Performance: The cylinder makes a "click" or "bang" sound when working, especially during the oil return process.

2. Solutions for marine cylinder noise
For different reasons for the noise generated by marine cylinders, the following solutions can be adopted:

Remove air from the system
Operation method:
Ensure that the hydraulic cylinder and hydraulic pipeline are completely sealed to prevent air from entering the hydraulic system.
Check the cylinder seals and pipe connectors regularly to ensure that there is no air leakage.
If there is air in the system, the air should be discharged through the exhaust valve or exhaust device to ensure that there are no bubbles in the system.
Effect: After removing the air, the cylinder will move more smoothly and the noise will be significantly reduced.

Replace the hydraulic oil and filter
Operation method:
The hydraulic cylinder manufacturer checks the quality of the hydraulic oil to ensure that the oil is clean, free of moisture and impurities.
Replace the hydraulic oil regularly and use hydraulic oil that meets the specifications, and avoid using aging, contaminated or non-compliant oil.
Check and clean the oil filter to prevent impurities in the oil from affecting the fluidity of the system.
Effect: Using clean and standard hydraulic oil can reduce friction and noise during cylinder movement.

Adjust the pressure of the hydraulic system
Operation method:
Check and adjust the key components of the hydraulic system, such as the pressure valve and overflow valve, to ensure that the working pressure of the system is within the design range.
Check the system pressure fluctuation through the pressure monitoring device, adjust the pressure in time, and prevent excessive or low pressure from causing system vibration or noise.
Effect: Stable pressure helps the smooth operation of the cylinder and avoids noise caused by pressure fluctuations.

Replace or repair worn parts
Operation method:
Regularly check whether the piston, piston rod, seal, etc. inside the cylinder are worn or aged. If any problems are found, the damaged parts should be replaced in time.
Check the support structure of the cylinder installation to ensure that there is no looseness or deformation.
Effect: After replacing the worn parts, the cylinder can work normally, reducing the friction and noise caused by wear.

Optimize the pipeline layout
Operation method:
Rationally arrange the hydraulic pipeline to avoid excessive bending and unnecessary corners. Minimize the friction resistance of the pipeline and maintain a large bending radius.
Use hoses instead of hard pipes, or choose pipe materials with smooth lining and wear resistance to reduce the noise generated when the fluid flows.
Effect: Reduce flow resistance and bubbles in the pipeline, and reduce noise.

Correctly install the cylinder
Operation method:
Ensure that the cylinder is aligned with the load when installed to avoid the cylinder from being subjected to eccentric load or unbalanced force.
Check the support structure of the cylinder to ensure that the cylinder is firmly fixed and will not loosen due to vibration.
Effect: After correct installation, the cylinder can be extended and retracted smoothly, reducing the noise caused by installation problems.

Improve the design of the oil return system
Operation method:
Ensure that the oil return pipeline is unobstructed, avoid improper position of the oil return port or pipeline blockage.
Optimize the design of the oil return system to avoid excessive or unstable oil return flow rate.
Effect: After the oil return system is optimized, it can return oil smoothly and reduce the noise caused by poor oil return.

Add noise reduction device
Operation method:
Install noise reduction devices such as mufflers and shock pads on key components of the hydraulic system (such as pumps, valves, cylinders, etc.).
Use sound-absorbing materials to wrap the outside of the hydraulic system to reduce noise transmission.
Effect: The noise reduction device can effectively reduce the overall noise level of the hydraulic system.

The reasons for the noise generated by marine cylinders are relatively complex, which may involve the quality of hydraulic oil, system pressure, cylinder installation, pipeline configuration and other aspects. According to different reasons, adopting corresponding solutions, such as removing air, using oil, adjusting system pressure, replacing worn parts, optimizing pipeline layout, etc., can effectively reduce noise and ensure the smooth operation of the hydraulic system. In addition, regular maintenance and noise monitoring are also effective measures to avoid noise problems.