What factors should be considered when choosing O-rings?

What factors should be considered when choosing O-rings?

February 21, 2021

O-rings are widely used in various dynamic and static sealing occasions because of their low manufacturing cost and convenient use.  

O-ring sealing mechanism:   

O-ring is an automatic two-way sealing element. During installation, its radial and axial pre-compression endows the initial sealing ability of the O-ring itself. It increases with the increase of system pressure. 

Factors to consider when choosing O-rings:   

1. Sealed form.   

According to the load type, it can be divided into static seal and dynamic seal; according to the sealing purpose, it can be divided into hole seal, shaft seal and rotary shaft seal; according to its installation form, it can be divided into radial installation and axial installation. For radial installation, for shaft seals, the deviation between the inner diameter of the O-ring and the sealed diameter d2 should be as small as possible; for hole seals, the inner diameter should be equal to or slightly smaller than the groove diameter d1.  

2. Working medium and working conditions.   

When selecting the O-ring material, the compatibility with the working medium must first be considered. The working conditions such as the pressure, temperature, continuous working time, and operating period of the seal must also be considered comprehensively.