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Why do mechanical seals fail and what can you do about it?

By February 20, 2017 No Comments

Mechanical seal failure is one of most common reasons that a pump fails. These seals retain fluid within the pump utilising two flat surfaces, one stationary and one rotating.

They are far more effective than the traditional pump shaft seals of soft packing, but, to get the best out of mechanical seals, you need to follow a few basic rules.

1. Don’t let the pump run dry

If your pump runs dry, you may only be 30 seconds away from acute mechanical failure. Mechanical seals can experience thermal shocks under the right (or wrong) conditions and can shatter rapidly.

2. Pumps shouldn’t vibrate

Pump vibration caused by improper alignment, pump imbalance or other issues can impact mechanical seals. Any vibration can damage your equipment, including shortening the life of your seals.

3. Don’t use hammers

Hammers can damage pumps in general and a common mistake is to hammer couplings onto the shaft. The faces of mechanical seals are fragile and easily damaged by any sort of hammering.

4. Have a mechanical flush seal plan

Mechanical seals must form part of an overall flush plan. Without a flush plan, contaminates and dewatered product can build up within the pump system. Seal life is subsequently affected when excessive heat or erosion impacts the seal.

5. Choose the right seal or materials

A seal must be installed to best suit the requirements of your system and the normal operating conditions. You must also take into consideration the non-process activities involved such as maintenance. Knowledge of mechanical seals and the variances is vital for their successful installation.

6. Operate the pump properly

Initial start-up procedures must be followed to ensure the smooth operation of your pump. Seal failure can occur when the motor of the pump trips and the shaft twists. The effectiveness of mechanical seals also relies on the two faces aligning properly, and this can be damaged by user error in installation and start-up procedures.

Mechanical seals should be purchased with the total lifetime costs in mind instead of the initial costs. If your system is operated in accordance with the above guidelines, you’ll increase the seal’s mean time between failures.

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