Pump Mechanical Seal


Mechanical seals are used to seal the ‘wet’ part of a pump and prevent leakage out of the intended wet area.

In the past, gland packing (compression packing) was used, but gland packing has several disadvantages compared to modern mechanical seals. Some of these disadvantages include:

  • Gland packing presses physically against the shaft and slowly wears away, which allows leakage.
  • The gland rubs on the shaft and slowly creates a groove on the shaft which may later need to be repaired.
  • Contact between the gland and shaft creates friction and this heat must be removed to prevent damage to the shaft and gland.
  • Friction between the gland and the shaft means that the pump motor has to work harder and a drop in efficiency occurs.

Despite its disadvantages, gland packing is still the cheaper of the two sealing options and remains in use.

Stuffing Box Arrangement

Stuffing Box Arrangement

3D Model Details

This 3D model shows all major components associated with a typical mechanical seal used for centrifugal pumps and other pump designs, these include:

  • Spring
  • Spring Retainer
  • Primary Sealing Ring
  • Flexible Diaphragm
  • Mating Ring
  • O-Ring
Additional Resources



Encyclopedia - saVRee