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How to choose the right O-ring? What factors should be considered?

Apr 23, 2018

How to choose the right O-ring seal?


 1, working media and working conditions


When selecting the O-ring material, the first consideration is the compatibility with the working medium. It is also necessary to comprehensively consider the working conditions such as pressure, temperature, continuous working time, and operating cycle at the seal. If used in rotating applications, the temperature rise due to frictional heat must be taken into consideration. Different seal materials have different physical and chemical properties.


2, sealed form


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


When installing axially, consider the direction of pressure. When the internal pressure, the O-ring outer diameter should be about 1-2% larger than the outer diameter d3 of the groove; when the external pressure, the inner diameter of the O-ring should be about 1-3% smaller than the inner diameter d4 of the ditch.