A mechanical seal is a device that helps join systems or mechanisms together by preventing leakage (e.g. in a plumbing system), containing pressure, or excluding contamination. The effectiveness of a seal is dependent on adhesion in the case of sealants and compression in the case of gaskets.
Almost everywhere where pumps with rotating shafts are used, a shaft seal is involved. The shaft seal forms a barrier between what is inside the pump and the atmosphere.
Seal performance greatly influences pump performance. When functioning correctly, the seal remains unnoticed. As soon as it starts to leak, however, significant problems can arise, either with the pump or the surrounding environment. The importance of the shaft seal must never be underestimated during pump design, operation, or maintenance.