Mechanical Seal Systems

How to Select the Right Seal for Mixing Applications

Page: 5/5

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3. Pressure compensator system for multiple agitators

Pressure compensators are generally equipped with a refilling hand pump. However, an automatic refill system is recommended if there is more than one agitator to exclude possible errors by the operating personnel (Fig. 10). The refilling pump is switched on when an LAL signal is sent from the pressure compensator (in addition compare Fig. 2). The pump is stopped with LAH. This configuration means that the pump operates for a short time and thus has a long service life.

Gallery with 11 images

Position monitoring of the pressure compensator provides very sensitive monitoring of the leakage behavior of each individual seal. This enables countermeasures to be initiated in good time if premature failure of the seal is imminent.

4. Pressure compensator system with independent cooling

Many plants don’t have a reliable central cooling water supply. An independent cooling system for several mechanical seals can be seen in Fig. 11. Provided that the pumps and the heat exchanger are connected to an emergency power generator, the seals can be kept at their normal operating temperature, even if there is a complete failure of the external power supply.

Integration into Processing Plants

Reliable operation of the mechanical seal depends on monitoring and control of the seal liquid supply systems. Its integration into the overall process control system is facilitated if the programmer has been provided with clear functional descriptions, logic diagrams and any necessary cause-and-effect diagrams.

The survival probability of the seal increases if the controlling parameters are clearly defined and interlocks have been properly implemented.


  • EKATO.THE BOOK, 2012 EKATO Holding GmbH, Freiburg
  • Erste Allgemeine Verwaltungsvorschrift zum Bundes-Immissionsschutzgesetz (Technische Anleitung zur Reinhaltung der TA-Luft), Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (2002)
  • Tietze, W.: Handbuch Dichtungspraxis, Vulkan, Essen (2000)
  • The formation of blisters on Carbon-Graphite seal faces, Pumps & Systems, (August 2005)

* B. Reichert, Research & Development, Ekato GmbH, Schopfheim/Germany.