How to Select a Mechanical Seal?

If the selection of mechanical seals for their application is done properly it can operate for many years without any issue. The operating conditions or application data must be identified properly to select the type of seals and material of construction to ensure the best performance from the seal throughout its lifetime. Below are the listings of the operating conditions and material characteristics to be considered for preventing improper material selection.
Things to Consider while selecting a Mechanical Seal
Liquid
The first step in the seal selection process is identifying the exact liquid to be handled. Seal material should be able to withstand the fluid being processed. There is an increased risk of seal failure if the seal material is not chemically compatible with the fluid.
Pressure
The type of seal required, balanced or unbalanced is determined by the pressure in the seal chamber and seal size.
Liquid Characteristics
To ensure the appropriate seal life it is important to know the viscosity of the liquid. Abrasive liquids can cause extreme wear and will lead to shortening seal’s life. External flush plan or use of double seal gives operators option to use mechanical seals on these tough liquids.
Temperature
Mechanical Seals materials must be selected to suitably handle liquid’s temperature. Different seal materials are rated for certain temperatures. Therefore, you should not exceed the temperature limit of these materials.
Emission and Reliability Concerns
When it comes to emission and reliability for an application, every company has their own standards and operating procedures. The seal type and arrangements chosen must meet the emission standards and desired reliability for the pump application. Double seals are peaking as the solution of choice due to environmental safety concerns among manufacturing companies.
Having understood the mechanical seal’s exact operating conditions, you can select the best suited construction and component material. Following characteristics need to be considered when selecting the seal’s construction material.
1. Flexibility
2. Wear resistance
3. Temperature constraints
4. Chemical resistance
5. Thermal expansion and conductivity
Also, when selecting the face and other component materials for the mechanical seal following material characteristics should be considered.
1. Low leakage and friction
2. Wear resistance
3. Corrosion resistance
4. Good thermal properties
Conclusion
Above mentioned are the operating conditions and material characteristics to be considered while selecting mechanical seals. Always consider that a mechanical seal approval is not comprehensive without a seal support arrangement. As you work with your mechanical seals manufacturer, remember that a mechanical seal recommendation is not complete without a seal support plan.
