explain

The shaft sleeve and sealing device can adopt a split or integral structure. Users can choose according to specific requirements.

Oil lubricated stern shaft seal is one of the key technologies in ship shaft systems. The following is a detailed introduction about it:

Structural composition

Sealing seat: usually made of metal materials such as cast iron or cast steel, with sufficient strength and rigidity to withstand the forces generated during the operation of the stern shaft, and provide installation foundation and support for other sealing components. Its design should ensure good fit with components such as the stern shaft tube.

Sealing ring: It is often made of materials with good elasticity and wear resistance, such as nitrile rubber. The shape and dimensional accuracy of the sealing ring require high precision, and its inner wall is tightly attached to the stern shaft to prevent lubricating oil leakage and seawater infiltration.

Wear resistant shaft sleeve: generally installed between the stern shaft and the sealing ring, used to protect the surface of the stern shaft and reduce wear. It is usually made of metal materials with good wear resistance, such as bronze. The surface hardness of the shaft sleeve is high, which can withstand the friction and compression of the sealing ring, extending the service life of the stern shaft.

Spring: used to provide pre tension between the sealing ring and the stern shaft, so that the sealing ring can better fit the surface of the stern shaft and ensure the sealing effect. The elastic coefficient of the spring needs to be reasonably selected according to specific sealing requirements and the working conditions of the stern shaft.

Oil hole and oil pipe: The oil lubrication stern shaft sealing device is usually equipped with inlet and outlet oil holes, which are connected to the oil tank and pressure control valve through external oil pipes. The inlet hole is used to inject lubricating oil into the sealing device, while the outlet hole is used to discharge used lubricating oil to ensure the circulation and renewal of lubricating oil, while maintaining stable oil pressure inside the sealing device.

working principle

• Formation of oil film: After lubricating oil enters the sealing device through the oil hole, a continuous oil film is formed between the stern shaft and the sealing ring. This oil film not only reduces the friction coefficient between the stern shaft and the sealing ring, reduces wear, but also plays a sealing role, preventing the mutual penetration of seawater and lubricating oil

Pressure balance: Adjust the oil pressure in different chambers of the sealing device through a pressure control valve to balance it with the external seawater pressure. For example, when the draft depth of the ship changes and causes a change in the external seawater pressure, the oil pressure inside the sealing device can be adjusted accordingly to ensure that the pressure difference on both sides of the sealing ring is within a reasonable range, thereby ensuring the stability of the sealing performance and preventing seawater from entering the ship and lubricating oil from leaking outside the ship.

advantage

Good lubrication performance: It can effectively reduce friction and wear between the stern shaft and sealing components, extend the service life of components, reduce maintenance costs and downtime.

Reliable sealing effect: Under normal working conditions, it can effectively prevent seawater from entering the cabin, protect the ship's equipment and cargo from seawater erosion, and also prevent lubricating oil leakage into the ocean, reducing pollution to the marine environment.

• Adapt to different working conditions: Based on the different navigation states of the ship and the working conditions of the stern shaft, such as speed, load, temperature, etc., the performance stability of the sealing device can be ensured by adjusting parameters such as oil pressure and temperature to adapt to various complex working conditions.

Common faults and maintenance

Aging and wear of sealing rings: Long term use can cause aging, hardening, cracking, and increased wear between the sealing ring and the stern shaft, thereby affecting the sealing effect. Regularly inspect the appearance and size of the sealing ring, and replace it promptly if it is damaged.

Lubricating oil leakage: It may be caused by damaged sealing rings, loose sealing seats, blocked oil holes, or ruptured oil pipes. Once a lubricating oil leak is discovered, the source of the leak should be immediately identified and corresponding repair measures should be taken, such as replacing the sealing ring, tightening the sealing seat, cleaning the oil hole, or replacing the oil pipe.

Abnormal oil pressure: Excessive or insufficient oil pressure can affect the normal operation of the sealing device. Excessive oil pressure may cause excessive wear or even damage to the sealing ring, while low oil pressure cannot ensure good sealing effect. Regularly check the oil pressure and adjust it through the pressure control valve to ensure that the oil pressure is within the specified range.