Mechanical Seal Failure

Any device is considered as failed when it is unable to perform satisfactorily as it was supposed to perform or designed with the intention to perform. Similarly, a mechanical seal is considered to have failed when leakage past the seal assembly causes either:


Now, if we come to the word Excessive it is very difficult to define it and will vary with the application. In some applications litres of fluid per hour will be acceptable depending upon the size, e.g., sealing some non-hazardous and non-expensive fluids. But for critical applications like sealing hazardous and expensive fluids such as H2S, Methane, fuels, etc. small drip is unacceptable and will be considered excessive. Therefore, practical seal failure definition is mostly dependent on operator experience.


The Mechanical seal failure may result from the following:


Knowing the symptoms of mechanical seal failure gives the best indication of action required to increase seal life expectancy in a particular application. An indication of the causes of seal problems can often be obtained by analysing the symptoms experienced in service. Following are the external symptoms related to mechanical seal failure,


Seal is making high pitched noise during operation:

This indicates:

Remedial actions:


Seal Hang-up

This indicates:

Remedial actions:


Seal leaks steadily

This indicates:

Remedial actions:


Seal failed after a very short period

This indicates:

Remedial actions: