O-ring lexicon

Axial seal

An axial seal is an O-ring assembly in which the seal is pressed in the direction of the component's axis. A typical application is sealing between two flat surfaces, such as on a flange.

What is an axial seal?

In an axial seal, the compression acts in the axial direction—that is, perpendicular to the annular contact surface. The O-ring sits in a groove and is compressed when the two components are joined together. This distinguishes it from a radial seal, in which the compression occurs across the axis between the inner and outer diameters. The axial seal is a classic design for static applications such as covers, flanges, and housing screw connections.

Why the Axial Seal Is Important for O-Rings

The installation type determines how the groove must be designed and in which direction the internal pressure acts on the seal. For axial seals, it is important to note whether the pressure is applied from the inside or the outside, as this determines which side of the groove the O-ring seals against. A correctly sized groove with the appropriate compression ensures a reliable seal without overloading the O-ring. Proper groove design prevents leaks as well as premature damage to the seal.

Key Points at a Glance

In an axial seal, the compression acts in the axial direction between two flat surfaces.
It is typically used in static applications such as flanges and covers.
The direction of pressure determines which side of the groove the O-ring seals against.

Calculate your groove accurately using our groove calculator. Refer to the overview for the appropriate tolerances.

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