company news about Mechanical Seal Selection

General Selection Principles
Mechanical seals are available in various types, including high-temperature and low-temperature mechanical seals, high-pressure and corrosion-resistant mechanical seals, high-speed mechanical seals, and mechanical seals for abrasive media, depending on the working conditions and the nature of the medium.

They can be further classified into pump mechanical seals, kettle mechanical seals, compressor mechanical seals, and special equipment mechanical seals based on the equipment they are used in.

When selecting a mechanical seal, one should choose different structural forms and materials according to their different uses.

At the same time, it is also necessary to select the appropriate flushing, cooling, and lubrication support system solutions based on the temperature and the nature of the medium.

To fully utilize the performance of the mechanical seal, it is essential to select the correct type according to the operating conditions.

Each type of seal can only effectively play its role when used within the specified range of use. If the selection and material are inappropriate or exceed the specified use conditions of the seal, it will cause a significant reduction in the performance of the mechanical seal, a shortened life, or even rapid damage.
The main parameters to consider in selection include: P - pressure of the sealed cavity (MPa), T - fluid temperature (℃), u - rotational speed of the sealing shaft (m/s), characteristics of the fluid to be sealed, sealing life requirements, leakage requirements, and the allowable effective space for installing the sealed cavity, etc.

The relationship between the working parameters of the seal and the structure and material of the mechanical seal can be roughly summarized as follows:

determine → unbalanced type, balanced type, single end face, double end face, multi-end face (multistage) according to the P value;

determine → rotating type, stationary type, fluid dynamic pressure type, non-contact type according to the v value;

consider the flash evaporation of the liquid film between the end faces, the thermal impact resistance during temperature fluctuations, the viscosity reduction and lubricity with increasing temperature, the heat resistance limit of the auxiliary sealing ring, the acceleration of corrosion due to temperature rise, the embrittlement of low-temperature materials, the polymerization or crystallization of materials, and other factors to determine the structure of the seal, the friction pair and auxiliary sealing ring material, the lubrication and cooling method, the flushing and insulation measures, and the cold insulation measures, etc.
Consider → corrosion reduces the service life, the presence of abrasive particles accelerates the wear of sealing parts, the high-pressure end face is prone to opening, low viscosity or impurities may cause dry friction problems, flammable, explosive, toxic, which may endanger environmental safety, and require special design: sealing structure, sealing parts material, lubrication method, isolation measures, safety measures.
Consider → sealing cavity size → limited space size of the sealing cavity, standard mechanical seal can not be installed, using elastic element structure specially designed, according to the service life requirements, such as rocket, missile launch device for a very short period of use, but the reliability requirements are extremely high, determine special design, use high-performance materials.
The above parameters not only need to be studied one by one but also need to be considered as a whole, because they influence and depend on each other.