Control and Feedback Systems

LEFF® Function - Low Emission Flip-Flop

Reducing water consumption is a key priority in sustainable production. GEA’s electronic LEFF function can save more than 90% water and cleaning agents during valve seat cleaning.

LEFF® function integrated in GEA T.VIS A-15 control top

Resource-efficient solution


At GEA we are continually innovating to improve our customers’ efficiency, reduce their consumption of valuable resources and improve sustainability.

The LEFF® function integrated in GEA T.VIS A-15 control tops has been awarded the GEA Add Better label* for its positive impact on reduced water consumption. Conventionally, mixproof valves run a time-based seat lifting cycle to clean valve seats and intermediate cavity. The LEFF® function is the smarter, more efficient way. The valve opens in a pulsating mode, controlled by path-measuring instead of fixed intervals. This increases the intensity of flushing and effectively shortens flushing times for water and chemicals. It has been proven to saves up to 92% of water and cleaning agent used.

*The add Better label relates to the LEFF® function integrated in GEA T.VIS control top, released in 2003, which saves 92% of water in comparison to conventional valve seat cleaning.

How does the LEFF® function works?

Benefits and supply details of the LEFF® function

  • LEFF® is integrated as a standard feature in the T.VIS® A-15 control top – the best choice for mixproof double-seat valves
  • No complicated programming required in the PLC
  • No additional system technology required
  • Automatic monitoring of the lift function
  • Significant cost reductions: up to 92 % savings of water and CIP media
VARIVENT® Mixproof valve type D and R

For double-seat valves it simply utilizes standard feedback units, without needing any special components. The straightforward configuration using two push buttons on the T.VIS® cap allows the LEFF® function to be activated separately at any time during set-up for the valve or double disc or even both.

Modulation of the valve disc during lifting makes it possible to drastically reduce cleaning agent consumption, respectively discharge into the drains and thus, reducing operating costs, compared to the conventional seat cleaning method.

Add Better | Resource efficient solution



Empowering customers with resource-efficient solutions
LEFF®: Smart lifting, sustainable cleaning.


LEFF® technology from GEA saves up to 90 percent on cleaning media

Find out your saving potential with the LEFF® function of GEA Varivent valves.

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