Question

• List four types of secondary seal used with rotary mechanical seals?
• Mist two advantages mechanical seals have compared to gland packing?

Answer 1

- There are four commonly used types of secondary seal found in mechanical seals;

• Gaskets.
• O-rings.
• Axial shaft seals.
•  polytetrafluoroethylene wedge-shaped rings.

- Polytetrafluoroethylene wedge-shaped rings seal used the most in rotary mechanical seals.

The pusher type of mechanical seals move axially along the rotating shaft or the sleeve to maintain the contact with the faces of the seal. This feature of these seals helps compensate for the wearing that may occur at the seal face, and wobbling due to misalignment. The pusher types of mechanical seals are used commonly, are less expensive and are easily available in the market in wide range of sizes and designs.