Triple-Acting Mechanical Seals

For Safe Operation During Challenging Processes

Triple acting mechanical seals feature two seal chambers. They are especially designed for demanding processes requiring a high degree of operational safety. They can be used for extreme pressure applications or for sealing extremely toxic or explosive products.

The characteristic feature of a triple-acting mechanical seal are its two seal chambers. Triple-acting mechanical seals can be used in a number of applications. The mechanical seal can be operated as a double-acting seal and the upper seal chamber acts as an unpressurized emergency seal.

The mechanical seal can also be operated with a pressure splitter which uses a specially designed pressure compensator that maintains the pressure in the upper seal chamber at half the value of that in the lower chamber. This enables the vessel to be operated at twice the pressure compared to a double-acting mechanical seal because the pressure is distributed over two seals.

For vessel pressures up to 200 bar, triple-acting mechanical seals are equipped with special supply systems which continuously replenish the seal liquid lost during operation.

Function and application

  • Triple-acting mechanical seal liquid lubricated for extreme pressure applications
  • Third pair of seal rings forms a second seal liquid chamber
  • A pressure splitting device can be fitted to significantly relieve the load on the seal rings
  • Design for demanding processes with a high degree of reliability
  • The high pressure seal is suitable for extremely toxic and explosive products


  • Function in emergency situations: if one pair of seal rings fails, the seal operates as a double-acting mechanical seal
  • An extended life time and less wear
  • Lower leakage rates

Working limits

  • Operating pressure: vacuum...200 bar (abs.)
  • Vessel temperature: -50...+400°C
  • Shaft size: 40...220 mm
  • Sliding speed: 0...3 m/s

The EKATO ESD ESD66H is most suitable for

  • Speciality chemicals
  • Hydrometallurgy


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