KNOLL Maschinenbau GmbH Schwarzachstraße 20
D-88348 Bad Saulgau

Tel.+49 (0) 7581/2008-90388
Fax+49 (0) 7581/2008-90140

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Vacuum filter VLO

Areas of application

The vacuum filter VLO is suited for cleaning cooling lubricants (CL) for grinding processes. A typical application is profile grinding with processing oil. Due to its simple scalability the filtration unit can be used locally for individual machines or centrally for machine groups. In any case the result is clean oil as well as pure, dry concentrate. And this all without use of filter aids.



  • Pure concentrate with low residual moisture
  • Continuous filter process without reverse flushing interruption
  • Scaling of filter capacities from 300 to 900 l/min (oil) with the same floor space possible
  • Subsequent extension of the unit possible
  • Redundant design of the filter modules possible
  • Different filter qualities per filter module possible




Filtration process

A lifting pump conveys the waste fluid into the inlet box. Having been cleaned, it flows from here through the endless belt into the filter chamber and subsequently into the clean tank. The filter pump creates a vacuum inside the filter chamber. Due to the high pressure difference on the surface of the filter, a thick filter cake (concentrate) builds up on the endless belt. This filter cake acts as a filter medium and collects tiny dirt particles.


Filter belt regeneration

The growing filter cake increases the flow resistance through the filter surface, causing the vacuum inside the filter chamber to rise. When the level reaches a defined threshold value, the belt drive cuts in and conveys the endless belt a little further. With permeable endless belt now over the filter surface, the volumetric flow rate increases again.


The endless filter belt passes through the following stations:

a) Filtration (separation of dirt particles)

b) Drying (extraction of fluid from the concentrate)

c) Brush-off device (removal of coarse particles)

d) Reverse flushing device (removal of ultrafine particles)


Picture of a KNOLL vacuum filter VLO