The self-cleaning Friess magnetic filter type ASMF is equipped with three or five concentrically arranged magnetic filter bars. Due to the use of highly efficient neodymium magnets with extremely high field strengths, the particles contained in the liquid are drawn onto the magnetic filter rods and held in place. The specially designed flow makes sure that the liquid flows slowly and evenly along the magnetic rods. Due to this, even very small particles down to 1 µm and less will be attracted by the magnetic field and will stick to the surface of the magnetic rod. Even if the magnetic filter rod is completely covered with dirt particles, the full flow is maintained.

When the maximum dirt holding capacity is reached, the magnetic filter is briefly rinsed. The inlet and outlet are closed for backwashing. Then the magnetic bars are pulled out of the stainless steel casing tubes with the help of a pneumatic cylinder. The dirt collected on the outside of the casing tubes flows out of the filter with some liquid by opening the bottom drain valve. Any residual dirt can then be flushed out by briefly opening the flushing valve. After a few seconds the filtration process can be continued.

As no consumables are used and only minimal energy is required for the backwash process, there are almost no operating costs.



  • Particle separation down to less than 1 µm
  • Self-cleaning
  • No consumables required
  • No additional energy requirement for the filtration process
  • Longer service life for cooling lubricant, washing water, grinding oil etc.
  • Improved surface quality for grinding processes


  • Filtration of cooling lubricants
  • Grinding
  • Honing
  • Lapping
  • Spark Erosion
  • Water jet cutting
  • Washing water