How to determine the O-ring size in seal design?

In sealing design, O-ring is a widely used sealing element, and its size selection is very important. The right O-ring size can ensure a stable and reliable seal performance, while the wrong size can lead to leaks or other seal failure problems. This article will cover the key factors and steps to consider when determining the size of O-rings.

First, determine the sealing groove size

The O-ring is installed in the sealing slot, so the size of the sealing slot needs to be determined first. The size of the sealing groove should be determined according to the section diameter and tolerance range of the O-ring. In general, the diameter of the sealing groove should be slightly larger than the cross-section diameter of the O-ring to ensure that the O-ring can be installed smoothly and form an effective seal.

Second, select O-ring section diameter

The section diameter of the O-ring is the key parameter for selecting the size of the O-ring. The selection of the section diameter should be determined according to the sealing requirements, working pressure, medium properties and the size of the sealing groove. Generally speaking, O-rings with larger section diameters have better sealing performance and pressure resistance, but too large section diameters may lead to installation difficulties or excessive wear of the sealing groove. Therefore, comprehensive consideration is needed when selecting the section diameter.

Third, consider the compression rate of the O-ring

The compression rate of the O-ring refers to the compression degree of the O-ring after installation. A suitable compression rate ensures a good sealing contact between the O-ring and the sealing groove. Excessive compression may lead to excessive deformation and failure of the O-ring, while too small compression may affect the sealing performance. Therefore, when determining the size of the O-ring, it is necessary to consider a reasonable range of the compression rate, which is usually between 10% and 30%.

4. Consider the hardness and material of the O-ring

The hardness and material of the O-ring also have an important impact on the sealing performance and service life. Too high hardness may lead to increased friction resistance between the O-ring and the sealing groove, while too low hardness may affect the sealing performance. Therefore, when selecting O-rings, it is necessary to choose the appropriate hardness and material according to the working environment and sealing requirements.

5. Follow standards and norms

When determining the size of the O-ring, the relevant standards and specifications should also be followed. For example, the International Organization for Standardization (ISO) has developed a series of standards on O-ring dimensions and tolerances that can be used as a reference for designers. In addition, different industries and fields may also have specific seal design standards and specifications that need to be followed.

Vi. Summary

Determining O-ring size is a key step in seal design. By comprehensively considering the sealing groove size, O-ring section diameter, compression rate, hardness, material and other factors, and following the relevant standards and specifications, you can ensure that the appropriate O-ring size is selected to provide a strong guarantee for the stable operation and maintenance of the equipment.