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A bit of Filter know-how
Explanations and clarifications of some frequently asked questions and terms used in filter technology.
Precoat filters are used when the highest required filter fineness is coupled with difficult filtration properties. An example is the abrasion occurring in the grinding oil during the precision machining of cast materials.
Belt filters use a flat filter belt of sieve fabric or filter fleece as a filter medium. The filter belt is acted upon with the suspension on its upper side and the liquid is discharged on the underside.
For the consumable-free operation of the HOFFMANN Suction belt filters,filter belts made of sieve fabric are used.
The geometric filter fineness indicates the diameter of a sphere that just cannot pass through the largest opening of the filter medium.
In the cake-forming filtration, the particles of a suspension are retained by the filter medium and form a growing layer, the filter cake.
Fleeces are composed of irregular superposed and partly interconnected fibres. Great variation possibilities exist for both the type of fibres and the type of solidification and surface treatment of the fleece material.
In a suction belt filter, a vacuum is created under the filter belt to accelerate the filtration. This allows more liquid to be filtered with the same footprint than with a purely hydrostatic operation.