WHAT IS A LABYRINTH SEAL？

Labyrinth seals are a type of seal which is commonly used in many industries. The main working environment includes high temperature, high pressure, and high rotational frequency. It is widely used in shaft ends and interstage seals of steam turbines, gas turbines, compressors, blowers, etc. Compared with other dynamic seals, labyrinth seals have the advantages of simple structure, strong adaptability to media, and long service life. Therefore, they have been widely used.

Sealing Principle of Labyrinth seals

The basic principle of the labyrinth seal is to reduce the fluid leakage by increasing the resistance of liquid flow. A general form of sealing structure is to arrange a series of non-contact orifices between the high and low pressure and the cavity between the orifices, thereby forming a tortuous flow path with high flow resistance between the high and low pressure. When a liquid with a certain pressure flows through this flow channel, part of the pressure energy is converted into kinetic energy when passing through the gap, and part of it is converted into thermal energy dissipation due to friction. After entering the cavity, this part of the kinetic energy that has not been converted into thermal energy is converted into potential energy, and when it is converted into potential energy in the cavity, it is further dissipated due to the loss of comprehensive expansion resistance. In this way, the flow channel can generate a differential pressure resistance of thorium, and through a series of energy dissipation, the leakage can be prevented.

There are many factors that affect the performance of the labyrinth seal, including the change of the seal structure form, the geometric size and the rotation of the characteristic shaft of the medium. These influencing factors are numerous and are not completely independent from each other, so the sealing effect of different seals varies greatly. Therefore, if we want to fundamentally understand the mechanism and characteristics of the labyrinth seal, we must carefully analyze various factors and know the main problems, so that we can get reasonable conclusions.

How to Classify the Structure of Labyrinth seals

Labyrinth seals can be classified in different ways according to different standards. There are three simple types of labyrinth seals commonly used in engineering, including through seals, staggered seals and stepped seals. Among them, the through labyrinth seal is famous for its simple structure, reliable operation and good performance advantages. It has been widely used in several different industries such as mechanical engineering, power transmission and chemical industry.

Due to the different classification of labyrinth seals, they can also be divided into single-stage labyrinth seals, double-stage labyrinth seals and multi-stage labyrinth seals. If the tooth structure of the seal is different, the labyrinth seal can also be divided into two categories which are seal plates and seal rings.

The structure of the labyrinth seal has a certain basic seal type. Different seal structure types, fluid flow directions and tooth shapes have certain effects on the sealing effect. We can improve the sealing effect by changing the geometric factors such as the shape of the labyrinth and the direction angle of the tooth tilt, to achieve an effective sealing effect.