What Is Mechanical Seal And Its Types?

Mechanical seals are crucial components of rotating machinery used in various industries such as chemical, oil and gas, and water treatment. They prevent fluid leakage from the pump or mixer shaft, which can cause damage to the equipment and harm the environment. In this article, we will discuss what mechanical seals are and their types.

What is a Mechanical Seal?

A mechanical seal is a device that helps to seal the gap between two stationary and rotating parts, such as a shaft and housing, to prevent fluid leakage. It consists of two principal parts, the stationary part, and the rotating part. The stationary part is usually mounted on the pump casing, while the rotating part is attached to the shaft.

The two parts of a mechanical seal are separated by a small gap called the seal face, where the seal faces are in contact with each other. The seal faces can be made from various materials such as carbon, ceramic, tungsten carbide, and silicon carbide. The seal faces can be of the same material or different materials depending on the application.

Types of Mechanical Seals

There are various types of mechanical seals, and they can be classified based on their design, application, and the materials used.

Pusher Seals

Pusher seals are the most common type of mechanical seals. They consist of a stationary seal face and a rotating seal face. The rotating face is pushed against the stationary face by a spring or a metal bellows. The bellows helps to compensate for any axial movement of the shaft.

Non-Pusher Seals

Non-pusher seals are similar to pusher seals, but they do not use a spring or bellows to push the rotating face against the stationary face. Instead, they rely on the pressure of the fluid to maintain the contact between the two faces. They are suitable for applications with low pressure and low speed.

Cartridge Seals

Cartridge seals are pre-assembled units that are easy to install and replace. They consist of a stationary and a rotating part enclosed in a cartridge. The cartridge can be inserted into the pump housing or mixer, and the mechanical seal is ready to use. Cartridge seals are suitable for applications with high pressure and high speed.

Split Seals

Split seals are designed for applications where it is difficult to remove the shaft from the equipment to replace the seal. They consist of two halves that can be assembled around the shaft without removing the shaft. They are suitable for applications where the equipment is large, and the shaft cannot be easily removed.

Metal Bellow Seals

Metal bellow seals are used in applications where the shaft has axial movement due to thermal expansion or vibration. They consist of a metal bellows that can accommodate the axial movement of the shaft without causing any damage to the seal faces.

Conclusion

Mechanical seals are essential components of rotating equipment used in various industries. They prevent fluid leakage and protect the equipment from damage. There are various types of mechanical seals available, and the choice of the seal depends on the application, the materials used, and the operating conditions. Proper selection, installation, and maintenance of the mechanical seal can improve the efficiency and reliability of the equipment. We are a mechanical seals supplier. If you are interested in our products, please contact us now!