• Suitable for dry start-up of the pump
  • Retains pump medium up to eight metres
  • Predictable lifetime due to condition monitoring
  • Low power consumption
  • Maximised maintenance intervals
  • Hard Metal Layer (HML) coating for extra durable grooved liners
  • Optional design: can be designed with divisible housing parts


This seal is mainly applied to dredging pumps, sewage water pumps, booster pumps and mining pumps.

How it works

The vacuum module also prevents air leakage through the seal into the pump if the pressure inside the pump is lower than atmospheric pressure. The Liquidyne seal is made up of different modules and fulfils the following functions:


  1. Sealing the pump shaft
  2. Reducing pressure
  3. Holding a vacuum


The order of the modules can vary and depends on the specific application. The seal can be roughly divided into two parts:


  1. A grooved bush that is clamped and rotates with the pump shaft;
  2. The stationary housing parts and rubber lip seals that are mounted against the pump housing.


The Liquidyne 3-Stage Vacuum can be lubricated, cleaned and cooled with the pump medium if it doesn’t contain too many (up to 100 µm) abrasive particles. The (water) lubricated Liquidyne lip seals run over a partially grooved bush placed over the pump shaft. The helical shape of the grooves and peripheral speed (RPM) of the liner create water flow (similar to aquaplaning) between the grooves and the lip seal. The water flows from the pump side to the drain of the seal. The condition of the seal is monitored by measuring the water flow from the pump side to the drain of the seal. The Liquidyne 3-Stage Vacuum is available for shaft diameters from 35 to 510 millimetres.


Technical information

Curious about the technical specifications? Download the technical product information for drawings, cross sections and datasheets.



The Liquidyne 3-Stage Vacuum consists of a grooved bush (stainless steel) with hard metal wear layer (HML), housing parts (bronze or stainless steel), NBR lip seals, Hastelloy® C4 springs and a stainless steel clamping ring.



Low-pressure pumps can optionally use a liner with a smooth and flat surface instead of a grooved surface.


Are our standard solutions not suitable for your application? Our engineers are more than happy to develop a custom-made sealing product!


Predictable lifetime

One of the main benefits of the Liquidyne is that the condition monitoring function is not just to simply monitor the condition of the seal, but it also creates a predictable lifetime. How? Over time, the grooves on the bush gradually wear down. Less water is transported over the bush and the amount of water leaving the drain decreases. When the drain flow is at 20% of the initial flow, maintenance needs to be planned.


By keeping track of this drain flow you can plan maintenance more efficiently, minimising the risk of sudden pump failure, optimise mean time between maintenance and reduce costs.

Condition monitoring explained with the predictable lifetime of maintenance

Quotation request

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Do you want more information or specialist advice about the Liquidyne 3-Stage Vacuum seal? Contact one of our experts!

Eric de Paauw

Account Manager

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