Mechanical seals: what they are and what they are used for

We can classify sealing devices into two groups, dynamic and static. Mechanical seals fall into the dynamic classification, together with gaskets. However, let's explain in more detail how a mechanical seal works.

What is a mechanical seal

Mechanical seals are dynamic sealing devices used to control leakage of liquids and gases in rotating equipment. The function of the mechanical seal is to prevent the escape of fluids along rotating shafts or shafts. Seals came to replace or provide a better solution than gaskets.

These seals have two faces: the static face, which is fixed on the machine, and the mechanical face, which rotates against the shaft to achieve a seal. The faces are perpendicular to the shaft. They also have wedge rings for each face, collar rings and springs to ensure permanent contact between the faces.

We can find mechanical seals in equipment such as:

• Rotary centrifugal pumps
• Centrifugal compressors
• Rotary compressors
• Axial flow compressors
• Agitators
• Water pumping systems
• Engine cooling systems

What to consider when buying mechanical seals

• Types of fluids: The first step in choosing a good mechanical seal is to identify the type of fluid you will be working with. This way you can choose a seal made of material that is resistant to the specific liquids, chemicals and/or gases in your processes. The viscosity of the fluid and the temperature at which they work are essential to understand what type of materials and characteristics the seals should have. A graphite mechanical seal has attributes that a galvanized one does not, therefore it cannot be used in the same circumstances.
• Pressure: Pressure is another important aspect, because then you can choose between a balanced or unbalanced seal.
• Seal properties: The specification manual of a mechanical seal should also consider aspects such as corrosion and wear resistance -both of the seal and its faces-, thermal properties, flexibility, chemical resistance and temperature restrictions, as well as thermal expansion and electrical conductivity properties.

ESGRAF has a wide variety of graphite seals, created according to the specific needs of each customer. In this way, ESGRAF's mechanical seals ensure optimum performance and adaptability to the requirements of each process.

Limitations to consider

Performance depends on graphite grade, grain orientation, temperature, load, pressure, speed, and operating environment. Material selection should be confirmed for your actual process conditions.

Information needed for a quote

To guide selection or prepare a quote, ESGRAF typically needs:

• Application and operating conditions (temperature, atmosphere, load).
• Dimensions, technical drawing, or CAD file when applicable.
• Required quantity.
• Requested grade or material currently in use.
• Observed issue with the previous part or lubricant, if any.

Request a quote

Share these details with our team at ESGRAF or request information. A specialist will review your application before recommending a grade or geometry.