A mechanical seal works by creating a running seal between the revolving and stationary components of a pump shaft. Unlike a compression packing gland, this device effectively minimizes leakage problems.
Mechanical seals are designed with a pair of primary seal faces, shaft packings, insert mountings and additional hardware, such as compression rings, gland rings and collars.
The main seal configuration involves two planar, lapped faces, which form a tight leakage track that crosses the shaft at a 90-degree angle. One face is encased in a housing to keep it motionless while the other face is attached to, and spins with the pump shaft. The two faces are typically made up of different compounds to avoid surface adhesion. Mechanical seals have four key sealing points, which include a primary seal face and three leakage points that are restricted by 0-rings, V-rings, wedges or gaskets.