Failure Pattern
Typical of high pressure systems, this pattern can be identified by the many small bites (nibbles) taken from the o-ring on the low pressure (downstream) side.
Problem Sources
- Excessive clearances
- Excessive system pressure
- O-Ring material too soft
- Degradation of o-ring by system fluid
- Irregular clearance gaps caused by eccentricity
- Improper machining of o-ring gland (sharp edges)
- O-Ring size too large for gland
Suggested Solutions
- Decrease gland clearances by machining
- Use back-up rings to prevent extrusion
- Use harder o-ring material
- Re-check elastomer compatibility with system chemicals
- Increase rigidity and improve concentricity of metal components
- Break sharp edges of gland to a minimum radius of .005″
- Install proper size o-ring
- Consider a reinforced composite seal such as rubber-bonded-to-metal