Canted coil springs in mechanical seals

Mechanical seals are a safe and reliable sealing method, widely used in fluid sealing. During sealing there is no direct contact with the shaft that would cause wear, so a better seal is obtained, leakage is reduced, and the safety and reliability of the machine improve.

The canted coil spring as compensation element

The mechanical seal structure of the inclined ring spring uses a canted coil spring as its elastic compensation element. The spring combines large elastic deformation with a small change in elastic force, which gives the seal a better sealing effect. In demanding conditions such as high temperature, high pressure and high speed, ordinary cylindrical coil spring seals struggle to meet the requirements.

For modern mass production, an axial end-face mechanical seal spring was developed in the form of the canted coil spring, also known as a spring finger contact. Its main feature is the use of an axial tightening ring as the compensation element, with a spring-push arrangement replacing the traditional mechanical seal. During tightening, each coil of the annular spring acts in parallel, tightening axially and rotating in the circular direction.

How the seal holds together

The seal relies on the elastic force of the canted coil spring to drive the axial movement of the static ring, compensating for the axial alignment error caused by wear and buffering oscillations and pressure changes under harsh working conditions. The spring maintains the balance of axial force between the sealing pair and forms a stable sealing film between the sealing faces, achieving dynamic sealing under the pressure of the sealing film itself.

Structural features

The coils of a canted coil spring are small in size and number, giving the spring good current-carrying capacity and economy. Even with large tolerance errors it maintains a constant force, which reduces spring deformation and compensates for surface unevenness and fit tolerances. The spring also accepts tightening deformation, so it works normally in harsh environments with oscillation and shock.

Radial and axial springs

Canted coil springs are divided into radial and axial types. The tightening force of a radial spring acts perpendicular to the centerline, along the radius of the ring, so this type is mainly used for connecting parts. Axial springs, whose tightening force is parallel to the centerline, are generally used as seals.