The mechanical seal is used in a pump, mixer and other mechanical engineering scenarios to contain the fluid within a vessel where a shaft rotates through a stationary (or rotating) housing.

Why is mechanical seal important in this situation? It is because the rotating shaft has to move in a wet environment, but there should not be the leakage of pressurized fluid. Hence, the role of a seal is quite critical.

Does it mean the seal stops the leakage completely? Well, on the practical grounds yes because there is no ‘visible leakage’.

There is a little leakage as the fluid vapors get released into the atmosphere from the faces of the seal, though. Since the quantity is hardly quantifiable, the seals are considered leak proof.

• The seals do not damage pump sleeve or shaft.
• Due to inboard springs that get adjusted as the seal faces wear, it is not required to do daily maintenance.
• Mechanical seals cause less power consumption than gland packing because of the lightly loaded faces.
• In mechanical seals, the lubricant doesn’t get washed out. Therefore, bearing contamination gets avoided in normal operational conditions.
• Plant equipment remains corrosion free.
• Relatively less maintenance and cleaning are required. It makes mechanical seals cost-effective.
• Oil seals prevent accumulation of dirt in the machine.