Mechanical Seal Failure: Main Causes and Solutions in 2025

Mechanical seal failures is a critical issue in centrifugal pumps, often caused by vacuum conditions leading to leaks and downtime. For example, issues like vibration or pressure loss trigger seal breakdowns. Therefore, understanding the knowledge of mechanical seals is essential to prevent pump issues. This guide explores vacuum-related causes of seal failure and offers solutions to enhance pump reliability. Learn more at John Crane’s Homepage.

Causes of Mechanical Seal Failure Under Vacuum

Vacuum conditions are a primary reason for mechanical seal leakage. For instance, engineers identify three key issues contributing to pump breakdowns:

Vibration and Collisions Leading to Seal Failure

• Cause: During pump evacuation, excessive vibration causes dynamic and static rings to collide, resulting in leakage or structural damage.
• Solution: Engineers stabilize pump operations to reduce vibration. For example, regular maintenance helps. See AESSEAL’s Homepage for tips.

Reduced Contact Pressure Causing Seal Malfunction

• Cause: Dynamic and static rings rely on medium pressure and spring force. Consequently, when the pump empties, pressure drops, leading to seal issues.
• Solution: Operators maintain medium pressure by increasing inlet liquid back pressure.

Loss of Cooling and Lubrication Triggering Seal Breakdown

• Cause: Self-flushing schemes lose cooling and lubrication during evacuation, causing dry friction and seal damage.
• Solution: For instance, engineers use external flushing with clean fluid. Refer to Flowserve’s Homepage for details.

Symptoms Indicating Pump Evacuation

Pump evacuation often leads to mechanical seal failure. Specifically, engineers observe these signs:

• Decreased motor current
• Significant pressure fluctuations
• Abnormal flow variations
• Unusual noise emissions
• Pump body vibration
• Elevated pump cylinder temperature
  As a result, these symptoms signal the need for immediate action to prevent seal issues.

Solutions to Prevent Vacuum-Related Seal Failure

To address seal failure causes, engineers apply their knowledge of mechanical seals. Below are common vacuum-related issues and solutions:

Inlet Leakage

• Cause: Leaks at the inlet pipeline or flange cause vacuum issues.
• Solution: Operators stop the pump and inspect pipelines. For example, tightening flanges prevents breakdowns.

Inlet Blockage

• Cause: Blockages in the inlet pipeline, filter, or impeller trigger vacuum.
• Solution: Operators clear blockages after flushing, reducing leakage risks.

Low Inlet Pressure

• Cause: Insufficient inlet pressure contributes to seal malfunctions.
• Solution: Engineers increase inlet liquid back pressure to maintain stability.

High Medium Temperature

• Cause: Excessive medium temperature creates saturated steam, causing pump issues.
• Solution: Operators lower the medium temperature and discharge steam fully.

Inlet Valve Issues

• Cause: Closed inlet valve or detached valve core induces vacuum.
• Solution: Operators open the valve or replace the pump to prevent issues.

Incorrect Outlet Opening

• Cause: Improper valve opening size causes vacuum and leakage.
• Solution: Engineers adjust valve openings to optimize performance.

Contaminated Sealing Oil

• Cause: Water in sealing oil triggers pump breakdowns.
• Solution: Operators dehydrate the sealed oil tank to restore function.

Low Liquid Level

• Cause: Insufficient liquid in the pump tower causes vacuum issues.
• Solution: Operators reduce the outlet valve or stop the pump until the liquid level rises.

Worn Impeller or Grinding Ring

• Cause: Severe wear on impeller or grinding ring leads to seal problems.
• Solution: Engineers replace worn components. Check World Pumps’ Resources for replacement guides.

Motor Reverse Rotation

• Cause: Incorrect motor rotation direction causes vacuum and breakdowns.
• Solution: Engineers correct motor rotation to prevent seal issues.

Preventing Mechanical Seal Leakage

Additionally, proactive maintenance reduces mechanical seal leakage. For example, engineers regularly inspect inlet pipelines, ensure proper valve operation, and monitor liquid levels to prevent vacuum conditions. Moreover, applying external flushing systems enhances seal reliability.

FAQs on Preventing Mechanical Seal Failure

How to maintain mechanical seals? Operators ensure lubrication and monitor liquid levels to prevent issues.

Why do seals fail under vacuum? For instance, vacuum causes vibration, pressure loss, or dry friction, leading to leakage.

How to prevent centrifugal pump vacuum? Specifically, engineers inspect pipelines and use external flushing to avoid breakdowns.

What are signs of pump evacuation? Symptoms like noise and vibration indicate seal risks.