Mechanical Seals for Pumps

28.11.2024

Any system involving multiple fluid-handling components must be sealed effectively. Mechanical seals connect components to prevent fluid or gas leaks to the outside and keep contaminants out. Pumps equipped with mechanical seals are durable, efficient, and widely used in industrial settings. This article explains how mechanical seals work, their types, and key benefits.

What is a Mechanical Seal?

Mechanical seals are ideal for operations involving various pressures, temperatures, and fluids. They prevent leakage along the rotating shaft of machinery while protecting the pump system from external particles. The process medium remains contained, which is crucial for hazardous fluids. A typical seal includes a rotating ring on the shaft and a stationary ring on the housing. Mostly used in centrifugal pumps, mechanical seals improve reliability and reduce maintenance costs.

Materials are chosen based on the medium, operating temperature, shaft size and speed, and system pressure.

Types of Mechanical Seals

Common types include:

Balanced and unbalanced seals
Pusher and non-pusher seals
Cartridge seals

These seals isolate two environments in centrifugal pumps with three sealing points:

Rotating surface
Stationary surface
Interface between the two

How Does a Mechanical Seal Work?

The sealing surfaces are pressed together by spring or hydraulic forces. A thin layer of liquid between them prevents dry friction, enabling shaft rotation while maintaining sealing integrity.