What is the compression ratio of O-ring?

The compression ratio of an O-ring refers to the proportion by which the cross-sectional diameter of the O-ring decreases after being subjected to compressive force. It is an important performance parameter that affects the sealing effect and service life of the seal. The following is a detailed explanation about the compression rate of O-rings:
1, Calculation formula
The calculation formula for O-ring compression ratio is: compression ratio (W)=(do - h)/do × 100%. Among them, do represents the cross-sectional diameter of the O-ring in the free state (mm), and h represents the distance between the bottom of the O-ring groove and the sealed surface, that is, the cross-sectional height of the O-ring after compression (mm).
2, Select Range
The selection of O-ring compression ratio varies depending on the application scenario and working conditions. Here are some common selection ranges:
Static sealing device: Generally, a compression ratio of 15% to 30% is selected to ensure good sealing effect.
Reciprocating motion seal: A compression ratio of 10% to 15% is usually selected to meet the sealing requirements during reciprocating motion.
Rotating motion seal: When selecting compression ratio, Joule heating effect must be considered. Generally speaking, the compression ratio of rotary motion seals is also selected to be 10%~15%. However, it should be noted that O-rings are only used for low-speed rotary sealing devices when used for rotary motion sealing.
3, Influencing factors
Work pressure: The greater the work pressure, the higher the required compression ratio to ensure sealing effectiveness.
Medium properties: The temperature, corrosiveness, viscosity, and other factors of the medium can also affect the selection of compression ratio for O-rings. For example, high-temperature media may cause the expansion of O-ring materials, so it is necessary to adjust the compression ratio appropriately.
Material hardness: The material hardness of O-rings also affects their compression performance. O-rings with higher hardness may experience less deformation when compressed, therefore requiring a higher compression rate to achieve the desired sealing effect.
4, Precautions
When installing O-rings, ensure that they are correctly placed in the groove and avoid excessive stretching or compression.
Regularly check the sealing effect of the O-ring, and replace it promptly if any leakage or damage is found.
Reasonably select the material and compression ratio of O-ring according to different application scenarios and working conditions to ensure its sealing performance and service life.
The compression ratio of O-ring is an important performance parameter, and its selection should be determined according to specific application scenarios and working conditions. By reasonable selection and installation, it can be ensured that the O-ring plays a good sealing role in mechanical equipment.