Linear&reciprocating-Application failures-Geometric deformantion

Failure mode

Permanent geometric deformation of seal 

profile

Failure cause

Pressure overload

Tolerance range of seal housing dimensions 

too wide

Thermal influence at thermoplastic seal 

material

Remedial measures

change geometry / material

improve seal housing

Failure mode

Deformation / twisting of seal component

Failure cause

Twisting of seal component By different friction at seal circumference (ovality / excentricity)

Remedial measures

Check roundness of cylinder tube

Check run-out of seal groove diameter

Failure mode

Geometric deformation to pressure side

Failure cause

Pressure built up between seals in sealing 

systems

Remedial measures

Piston: install only one double acting piston 

seal

Rod: provide pressure relief function (seal or 

housing)

Failure mode

Geometric deformation of seal and housing

Failure cause

Pressure built up between seals in sealing 

systems

Remedial measures

Add back-up ring

Provide pressure relief function (seal or 

housing)

Failure mode

Geometric deformation and splitting of seal 

of wear ring (to pressure side)

Failure cause

Pressure built up between seal and wear ring

Radial gap in wear ring too small and closed 

at high temperatures (thermal elongation:

steel / plastic = 1:10)

Remedial measures

Gap in wear ring according recommendations