How Long Do Mechanical Seals Last

Mechanical seal failure is one of the most common causes of equipment downtime in industrial facilities. When a seal fails prematurely, it can result in costly repairs, lost production, and potential safety hazards.

Many factors affect seal life, from operating conditions to seal design to installation practices. In this post, we’ll dive into the typical lifespan you can expect from different types of mechanical seals. We’ll also explore the key factors that impact seal longevity and share best practices to extend the life of the seals in your facility.

Typical Lifespan of Different Mechanical Seals Types

Factors Affecting Mechanical Seal Lifespan

Operating Conditions

Extreme temperatures, whether high or low, can cause thermal expansion or contraction of seal components, potentially leading to increased friction, leakage, or seal face damage. Seals exposed to high pressures must withstand greater forces, which can accelerate wear. High shaft speeds also generate more heat and place greater stress on the seal faces.

Seal Design

Seal faces that are too flat or too wide can be prone to thermal distortion and uneven wear. Inadequate balance diameter can result in excessive face pressure and frictional heat generation. Improper spring selection may lead to inconsistent face loading and poor tracking.

Materials

The materials used in a mechanical seal’s components have a direct impact on its lifespan. Seal faces, elastomers, metals, and lubricants must be selected to withstand the chemical, thermal, and physical stresses present in the application.

Common face materials include carbon, silicon carbide, tungsten carbide, and silicon nitride. Each offers distinct advantages in terms of hardness, thermal conductivity, chemical resistance, and tribological properties. Elastomeric components such as O-rings and wedges are typically made from high-performance materials like FKM, PTFE, or FFKM to ensure compatibility and resilience.

Installation

Misaligned shafts can cause uneven loading and accelerated wear of the seal faces. Improperly sized seal chambers may restrict coolant flow or allow excessive turbulence. Over-tightening or under-tightening of gland bolts can result in distortion or inadequate compression of the seal components.

Fluid Compatibility

Abrasive particles in the fluid can embed into the seal faces, causing scoring and increased leakage. Corrosive fluids can attack seal components, leading to material loss, pitting, and structural failure. Incompatible fluids may cause elastomeric components to swell, shrink, or lose mechanical strength.