The most common causes of dry gas seal failure are liquid or contaminants entering the seal gas, as well as improper operation that destroys the gas film.
These issues are mainly related to seal gas quality, operating conditions, and maintenance of the support system.
1.Poor Gas Quality Is the Most Common Cause
Seal gas carrying liquid or contaminants:
If the seal gas contains liquid such as oil or water, the liquid may vaporize and expand rapidly when passing through the seal gap due to pressure reduction. This can instantly destroy the gas film, causing direct contact between the rotating and stationary rings. The temperature then rises sharply, leading to thermal cracking or even catastrophic failure of the seal rings.
Failure of the filtration system:
Blocked filters or insufficient filtration accuracy allow contaminants to enter the seal chamber, resulting in seal ring fracture or accelerated wear.
Poor seal gas quality:
After pressure reduction through the regulator, liquid components may condense out of the seal gas. If not removed in time, seal face wear will increase significantly.
2.Improper Operation Can Easily Cause Damage
Reverse rotation or low-speed operation:
For unidirectional groove seals, reverse rotation or prolonged low-speed operation prevents formation of the protective gas film, which may cause direct contact and cracking of the seal rings.
Improper startup and shutdown procedures:
During startup or shutdown, improper pressure balancing may allow process gas to backflow and contaminate the seal faces, or the barrier/separation gas may not be supplied in time.
Field operational errors:
Sudden temperature changes may cause seal ring cracking, while failure to drain accumulated liquid regularly may result in liquid carryover into the seal.
3.Vibration and Installation Problems
Excessive machine vibration:
Severe vibration caused by equipment malfunction may exceed the seal’s design limits and lead to seal damage.
Incorrect installation:
Installing the drive-end and non-drive-end components incorrectly, or failure of the C-ring due to wear or breakage, may result in leakage.
Failure of support systems:
Failure of the separation gas system may allow lubricating oil to enter the dry gas seal, contaminating the seal faces and causing seal failure.