The main reason for mechanical seal failure

Knowledge of Mechanical Seals: Solving Centrifugal Pump Vacuum Issues in 2025

Introduction to Mechanical Seal Failures
Mastering the knowledge of mechanical seals is essential for engineers to prevent centrifugal pump failures. For example, vacuum conditions often lead to mechanical seal breakdowns, causing leaks and downtime. Therefore, this guide explores vacuum-related seal failures and practical solutions to enhance pump reliability. Learn more about sealing technology at Wikipedia: Mechanical Seals.

Vacuum-Induced Seal Failures
Vacuum is a primary cause of mechanical seal failure. Specifically, engineers identify three key issues:

1. Vibration and Collisions

• Cause: During evacuation, excessive pump vibration occurs. Consequently, dynamic and static rings collide, leading to leakage or structural damage.
• Solution: Engineers stabilize pump operations to minimize vibration. See our Pump Maintenance Guide for tips.

1. Reduced Contact Pressure

• Cause: Dynamic and static rings rely on medium pressure and spring force. When the pump empties, medium pressure drops, reducing contact and causing seal failure.
• Solution: Operators maintain medium pressure by increasing inlet liquid back pressure.

1. Loss of Cooling and Lubrication

• Cause: Self-flushing schemes lose cooling and lubrication during evacuation, resulting in dry friction and seal damage.
• Solution: Engineers use external flushing with clean fluid, as outlined in Pump Industry Magazine.

Symptoms of Pump Evacuation
For instance, engineers observe these signs when a centrifugal pump experiences vacuum:

• Decreased motor current
• Significant pressure fluctuations
• Abnormal flow variations
• Unusual noise emissions
• Pump body vibration
• Elevated pump cylinder temperature
  These symptoms indicate urgent action to protect mechanical seals.

Causes and Solutions for Pump Vacuum
Knowledge of mechanical seals empowers engineers to address vacuum issues. Below are common causes and solutions:

1. Inlet Leakage

• Cause: Leaks at the inlet pipeline or flange.
• Solution: Operators stop the pump and inspect pipelines and flanges.

1. Inlet Blockage

• Cause: Blockages in the inlet pipeline, filter, or impeller.
• Solution: Operators clear blockages and perform maintenance after flushing.

1. Low Inlet Pressure

• Cause: Insufficient inlet pressure.
• Solution: Engineers increase inlet liquid back pressure.

1. High Medium Temperature

• Cause: Excessive medium temperature creates large saturated steam.
• Solution: Operators lower the medium temperature and discharge steam fully.

1. Inlet Valve Issues

• Cause: Closed inlet valve or detached valve core.
• Solution: Operators open the valve or replace the pump.

1. Incorrect Outlet Opening

• Cause: Outlet opening too large or small.
• Solution: Engineers adjust valve openings appropriately.

1. Contaminated Sealing Oil

• Cause: Water in sealing oil.
• Solution: Operators dehydrate the sealed oil tank.

1. Low Liquid Level

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

1. Worn Impeller or Grinding Ring

• Cause: Severe wear on impeller or grinding ring.
• Solution: Engineers replace worn components. Check our Seal Replacement Guide for details.

1. Motor Reverse Rotation
   • Cause: Incorrect motor rotation direction.
   • Solution: Engineers correct the motor rotation promptly.

Preventing Vacuum-Related Seal Failures
Additionally, proactive maintenance enhances the knowledge of mechanical seals. For example, engineers regularly inspect inlet pipelines, ensure proper valve operation, and monitor liquid levels to prevent vacuum conditions.

FAQs on Knowledge of Mechanical Seals

1. Why do mechanical seals fail under vacuum? Vacuum causes vibration, pressure loss, or dry friction.
2. How to prevent centrifugal pump vacuum? Engineers inspect pipelines, maintain pressure, and use external flushing.
3. What are signs of pump evacuation? Symptoms include noise, vibration, and pressure fluctuations.
4. How to maintain mechanical seals? Operators ensure lubrication and monitor liquid levels.