How to solve the leakage problem of rubber seals in high temperature and high pressure environment?

Leakage of rubber seals in high-temperature and high-pressure environments is a complex problem, and here are some ways to solve this problem:

In terms of material selection

Choose rubber materials that are resistant to high temperature and high pressure

Fluoroelastomer (FKM) is a commonly used rubber material that can withstand high temperatures and high pressures. It can work for a long time in the temperature range of -20°C - 200°C and has good chemical and oil resistance. For example, in an automobile engine's sealing system, fluoroelastomer seals can withstand the pressure of high temperatures of oil and combustion gases, effectively preventing leakage.

Perfluoroelastomers (FFKM) have superior performance, maintaining good elasticity and sealing properties under extreme temperature conditions around -20°C to 300°C. It has extremely high chemical stability, can withstand the erosion of almost all chemical media, and is suitable for high-temperature and high-pressure sealing environments in high-precision fields such as aerospace and semiconductors.

Consider the hardness and elasticity of the material

The seal material needs to have the appropriate hardness and elasticity for high-temperature and high-pressure environments. Too-hard materials may not fill the seal gap well, while too-soft materials are susceptible to squeezing out under high pressure, causing leaks. In general, it is appropriate to choose a rubber material with a hardness of 70 - 85 Shore A. This hardness of the material ensures both sufficient elasticity to accommodate small deformations of the sealing surface and stability of the shape under high pressure.

Seal design optimization

Sealing structure design

The use of a reasonable sealing structure can effectively improve the sealing performance. For example, lip seal construction is a common design. In an environment of high temperature and high pressure, the lip of the lip seal can be tightly attached to the sealing surface, and under the action of pressure, the lip will produce a certain deformation, which further enhances the sealing effect. Like piston rod seals in hydraulic systems, lip seals prevent hydraulic fluid from leaking at high pressures.

For some special high-temperature and high-pressure vessels, a double-sealing structure can be adopted. The inner and outer seals work together to reduce the risk of leakage even if the outer seal is slightly damaged, the inner seal can still act as a seal.

Size design optimization

Accurate seal sizing is critical. The inner and outer diameters of the seal need to fit tightly with the sealing part. When designing, the coefficient of thermal expansion of rubber at high temperatures should be taken into account. Generally speaking, a certain amount of expansion space should be reserved to prevent the seal from being damaged or losing its sealing effect due to excessive expansion at high temperatures. At the same time, the thickness of the seal also needs to be reasonably designed to ensure that it has enough strength to resist the pressure under high pressure.

Installation and maintenance

Install it properly

Before installation, ensure the surface quality of the sealing part. The sealing surface should be flat and smooth, without obvious scratches, pits, and other defects. During installation, avoid excessive stretching, twisting, or scratching of the seals. For example, use a dedicated installation tool to install an O-rubber seal, and follow the correct installation orientation and steps to prevent leaks caused by improper installation of the seal.

For the installation of seals in high-temperature and high-pressure environments, it is also necessary to pay attention to the cleanliness of the installation environment. Any impurities, such as dust, metal shavings, etc., entering the sealing part may damage the seal or affect the sealing effect.

Regular maintenance and inspection

Establish a regular maintenance system to inspect the rubber seals in use. The inspection contents include whether the appearance of the seal is damaged or deformed and whether there are signs of leakage in the sealing part. In a high-temperature and high-pressure environment, rubber seals may deteriorate and harden due to long-term use. Once a problem is found with the seal, it should be replaced in time to avoid leakage accidents.

At the same time, attention should be paid to monitoring the temperature and pressure changes in the sealing environment. If the temperature or pressure is outside the design range of the seal, timely action is required, such as adjusting the operating parameters or replacing the seal with a more suitable one.