Every mechanically moving component or machine on board a ship generates vibrations. The vibrations in marine engines are caused by periodic or random oscillations around an equilibrium point.
When these same vibrations occur in larger machines operating under heavy loads (2-stroke marine propulsion engine), the intensity of vibration levels increases due to large mass rotation and combustible gas forces inside the machinery.
When vibration levels exceed the minimal level, i.e. when a mechanical system has one or more frequencies, engine components may deform or break. As a result, it is critical to dampen the vibration through some external arrangement.
When a two-stroke marine propulsion engine is in operation, it is subjected to three types of vibrations:
1. Longitudinal Vibration
This type of vibration is caused by guide forces generated by transverse reaction forces on the crossheads.
When the connecting rod and crankshaft mechanism converts reciprocating motion into rotary motion, transverse reaction forces are generated. Such vibrations cause the engine top to move away from the ship, causing rocking or twisting.
2. Axial Vibration
Axial vibration is a type of longitudinal shafting vibration that occurs in the crankshaft due to radial and tangential forces.
3. Torsional Vibration
Torsional vibration occurs in the crankshaft of an engine as a result of tangential forces acting on the crankshaft when it rotates at a certain RPM.
All of the aforementioned vibrations can cause internal component wear, loosening of holding bolts, damage to the engine structure, and even crankshaft failure.
Vibration Compensator
On board a commercial vessel, a vibration compensator is an essential piece of equipment. Its primary function is to reduce the amount of vibration produced by the ship’s engines and other machinery.
This vital piece of equipment aids in the stability of the vessel in rough waters and can prevent damage to the hull and other parts of the ship. A commercial vessel would be at risk of capsizing or sinking if it did not have a vibration compensator.
Vibrations on board ships can result in:
- Engine performance is limited.
- Cracking
- Mechanical strengths will be reduced.
- Unusual wear and tear on rotating machinery
- Electronic component failure
Vibration compensators function by absorbing the energy emitted by the vessel’s vibrations. This energy is then dissipated, either by using special materials or by redirecting it away from the vessel itself.
Guide force and unbalanced moments, axial thrust, hull beam and propeller induced vibrations are all well-known problems with low speed two-stroke diesel engines. Vibrations frequently cause engine performance to suffer, as well as cracking, reduced mechanical strength, abnormal wear on rotating machinery, and electronic component failure.
The servo-driven moment compensator reduces or even eliminates the source of vibration because of its unique technology that generates an exact opposite direction with a counterforce identical to the force induced by the engine. The imbalance is corrected, and no stress or vibrations are transmitted to the engine foundations or adjacent structures.
Vibration compensators can even generate electricity in some cases, which can then be used to power onboard devices or systems.
Compensator Facts
- Engine performance and comfort have both been improved.
- Reduced energy consumption and improved fuel economy When used in dependent operations.
- Force and direction are easily adjusted.
- Installation is simple and does not disrupt operations. Maintenance expenses have been reduced.
Whether or not a resonance exists, reducing external moments and guide force moments results in better and smoother running engines. The vibration compensator can also be used to reduce wear on most engine-related equipment as a preventive maintenance tool. The same with marine boiler Kangrim Repair, maintenance for burners and IGS, vibration compensator also needs regular check ups to extend its service life.
The installation of the vibration compensator is a relatively simple project that does not interfere with the vessel’s operation. After installation, no additional adjustments or operational attendance are required.
