Deep-Bed Filters

First-class raw materials and a mature technology for the manufacturing are essential for the quality of the SF Deep-Bed Filters.

The advantages of SF Deep-Bed Filters:

  • high level of safety
  • efficiency & effectiveness
  • easy handling


Cellulose fibres form the basic structure of the filter beds. By the fibrillation of the cellulose fibres and the integration of highly porous diatoms, extremely filtration-active structures are built up which, if necessary, are loosened up with perlites or coarser kieselguhrs.

The composition and the structure of deep-bed filters are therefore comparable to an extremely close-meshed, three-dimensional sieve with countless ramifications. In the ever-narrowing pore labyrinth, particles and microorganisms are mechanically held back. The particles are thereby deposited in the pores of the filter medium.

1 surface filtration, sieve effect
2 deep-bed filtration, mechanical absorption
3 deep-bed filtration, adsorption, accumulation
4 drain side, wet-solidified

The deep-bed filter effect can also be efficacious for particles that are smaller than the pores of the filter sheet. Therefore, the filtration effect of filter sheets is not given by the indication of pore diameters as it is the case for membranes. The characterisation of the filtration capacity is rather performed by the indication of the water permeability under defined conditions.

Three parameters are thus responsible for the retention capacity of filter sheets:


  • the surface filtration resp. the mechanical sieve effect
  • the deep-bed filtration, the mechanical absorption
  • the adsortption effect
 Wine and fruit juice Beer 
 Flow ratePressure differenceFlow ratePressure difference
Sterile filtration350 l/h m²1bar1,2 hl/h m²1,5 bar
Clarifying filtration750 l/h m²3bar1,5 hl/h m²2,0 bar


The optimal selection of the filter sheet means, on the one hand, receiving the highest possible quantity output and on the other hand, a sufficient filtration capacity. Other important criteria are pressure differences and flow velocity. In order to avoid a development of turbidity, depending on the kinds of filtration and the medium, certain filtration velocities must not be exceeded.