15 Tips to Maintain Mechanical Seals

Mechanical seals are vital components in many industrial applications, particularly in centrifugal pumps. Proper maintenance of mechanical seals is crucial for ensuring equipment reliability, efficient operation, and extended seal life.

This article provides 15 essential tips for maintaining mechanical seals, helping you avoid premature failure and optimize performance.

1. Lubrication

Ensure that the correct lubricant is used, as specified by the seal manufacturer. Avoid using incompatible lubricants, as they can lead to seal degradation and failure. Regularly check the lubricant level and quality, and replace it as necessary.

2. Avoid Dry Running

Dry running occurs when a mechanical seal operates without a fluid film between the seal faces, leading to excessive wear and premature failure. To prevent dry running, ensure that the seal chamber is properly filled with the appropriate fluid before starting the equipment. Monitor the fluid level and maintain it within the specified range.

3. Clean Seal Faces

Regularly inspect and clean the seal faces to remove any debris or build-up. Use a soft cloth and an approved cleaning solution, as recommended by the seal manufacturer. Avoid using abrasive materials or harsh chemicals that can damage the seal faces.

4. Control Contamination

Contamination in the process fluid can lead to mechanical seal failure. Install appropriate filtration systems to remove particulates and maintain fluid cleanliness. Regularly monitor the condition of the filters and replace them as needed. In applications with high levels of contamination, consider using cyclone separators or other specialized equipment to protect the seals.

5. Temperature Control

Ensure that the process fluid temperature remains within the specified range for the seal materials. If necessary, implement cooling systems or heat exchangers to maintain the proper temperature.

6. Pressure Management

Excessive pressure can cause mechanical seal failure by overloading the seal faces and secondary seals. Ensure that the system pressure remains within the design limits of the seal. Install pressure relief valves or other protective devices to prevent pressure spikes.

7. Vibrations and Alignment Control

Vibrations and misalignment can cause mechanical seal failure by inducing excessive wear and leakage. Regularly check the alignment of the pump shaft and coupling, and correct any misalignment issues promptly. Monitor vibration levels using appropriate sensors and analysis techniques, and take corrective action if vibrations exceed acceptable limits.

8. Flush Systems

Flush systems provide a clean, cool, and compatible fluid to the seal chamber, helping to control temperature, lubricate the seal faces, and remove contaminants. Ensure that the flush system is properly designed, installed, and maintained. Regularly inspect the flush fluid for contamination and replace it as necessary. Monitor the flow rate and pressure of the flush fluid to ensure proper operation.

9. Replace Worn Parts

As mechanical seals wear over time, it is essential to replace worn components before they cause failure. Regularly inspect the seal for signs of wear, such as increased leakage, visible damage, or changes in performance. Replace worn parts, such as seal faces, secondary seals, and drive pins, as recommended by the seal manufacturer. Use only genuine replacement parts to ensure proper fit and performance.

10. Leakage Control

While some leakage is normal for mechanical seals, excessive leakage can indicate a problem. Establish acceptable leakage rates based on the seal design and application requirements. Regularly monitor the leakage rate and investigate any sudden increases or changes in leakage behavior.

11. Performance Monitoring

Regular monitoring of mechanical seal performance can help detect potential issues before they lead to failure. Establish a baseline for key performance indicators, such as leakage rate, temperature, and vibration levels. Use appropriate sensors and data acquisition systems to collect and analyze performance data. Regularly review the data and trend it over time to identify any deviations from normal operation.

12. Cooling Systems Oversight

In applications where mechanical seals require external cooling, ensure that the cooling system is properly designed, installed, and maintained. Regularly inspect the cooling system components, such as heat exchangers, pumps, and piping, for signs of damage, corrosion, or fouling. Monitor the cooling fluid temperature and flow rate to ensure proper operation.

13. Proper Storage

When mechanical seals are not in use, it is essential to store them properly to prevent damage and ensure their readiness for installation. Store seals in a clean, dry, and temperature-controlled environment, away from direct sunlight and sources of contamination.

14. Operate Within Design Limits

To maximize mechanical seal life and performance, operate the equipment within the design limits specified by the manufacturer. This includes parameters such as pressure, temperature, speed, and fluid compatibility. Avoid subjecting the seals to conditions outside their design envelope, as this can lead to premature failure and reduced reliability.

15. Proper Installation

Follow the manufacturer’s installation instructions carefully, paying attention to factors such as seal orientation, alignment, and torque specifications. Ensure that the seal chamber is clean and free of debris before installation. Verify that all connections, such as flush lines and cooling systems, are properly installed and secured.

FAQs

Should you lubricate a mechanical seal?

Yes. Use the correct lubricant as specified by the seal manufacturer, and regularly check the lubricant level and quality. Avoid using incompatible lubricants that can cause seal degradation and failure.

What is the lifespan of a mechanical seal?

On average, a well-designed and properly installed mechanical seal can last between 18 to 24 months under normal operating conditions.