Depth filter elements (prefilters)

Depth filter elements (pleated, wound, thermally bonded) are intended for high performance preliminary and clarifying filtration of neutral, aggressive liquid and gaseous media (compatible with element materials), and also they are used as prefilters which ensure reliable protection of membrane filter, elongating its lifetime. Depth filters can be also used as final filters in the cases when there is no need to clean a medium completely from particles exceeding specified size.

Mechanisms of depth filtration

Technofilter depth filters ensure the retention of particles from 0.5 to 100 μm. They consist of numerous layers of fibrous materials - polypropylene, fiberglass, cellulose. Depending on the thickness and the efficiency of the filter layer, the depth filters retain 95-99% of all particles larger than the filtration ratio.

The filtration process takes place mainly in the depth of the filter material due to mechanical confinement, as well as adsorption mechanisms.

Depth filters can be compared by composition and structure of the material with a voluminous labyrinth sieve, which consists of extremely small cells with the finest and infinitely branched channels. They form a hollow structure equal to approximately 70-85% of the total volume of the filter, which provides a high ability to trap microparticles.

Various suspensions, microorganisms, colloids, lipids are retained while following the long path of this labyrinth, the mechanical effect being enhanced by the adsorption effect, especially in microglass fiber materials. Unlike membrane filters, depth filters are characterized by increased dirt holding capacity and life-time, so their use is necessary in almost all technological filtration schemes.

Pleated depth filter elements

For high performance preliminary and clarifying filtration we offer the whole range of fiber pleated depth filters on the basis of nonwoven materials made of polypropylene fibers, fiberglass and various filter boards.

Technofilter pleated depth filters are highly effective (they retain 98-99.95 % of overall particles and colloid contaminations with the size exceeding filter separation limits), they provide high flow rate and resource at low differential pressure in long term operation processes. A stable matrix and thermal and chemical resistance of materials make it possible to wash, sterilize and regenerate filters multiple times.

Depth pleated filters are used as prefilters for reliable protection of membrane filters, extending their service life, and are also used as final filters in cases where absolute purification of the medium from particles larger than a certain size is not required.