precoat filters

Filtration solutions for the treatment of coolant lubricants.

Cartridge filter systems: Precoat filters
(AS, AST, ASG)

Where is a precoat filter actually used? In the machining of metallic surfaces, cooling lubricants are used for cooling, lubrication and flushing. In order to protect the environment, the contaminated cooling lubricants, such as oils or machining emulsions, are not disposed of, but are cleaned with the help of precoat filter systems in order to make them available to the process again with an appropriate degree of purity and to integrate them into the cycle over long periods of time.
Precoat filters are often used in grinding and honing processes, in finishing, lapping, eroding, pressing and rolling as well as in ultra-fine filtration.

Precoat filter with wet discharge, Type AS

Conventional precoat filtration with wet discharge; the sludge treatment and drying takes place in secondary filters.

Precoat filter with dry discharge, Type AST

One advantage over conventional precoat filtration is the low space requirement, as no additional secondary sludge treatment is necessary. Sludge treatment and drying takes place directly in the precoat filter on the filter cartridges with subsequent dry filter cake discharge.

Electroplating precoat filter, Type ASG

Type ASG precoat filters are ideal for cleaning electroplating baths (acid baths), treatment of salt solutions, electrochemical processing and the treatment of other aggressive media as well as for ultra-fine filtration.

3D image of a precoat filter system with FAUDI logo

how does a
precoat filter
work?

The FAUDI precoat filter consists of a pressure vessel and is divided into a dirty and clean part by an intermediate plate in which the filter elements are installed. The dirty medium is filtered through the filter elements, whereby the flow through the filter elements is from the outside to the inside. However, before the actual filtration of the contaminated medium begins, the filter elements must be precoated with filter aid. During the so-called precoating process, the filter aid is deposited on the filter elements and forms a precoat layer, which ultimately constitutes the filtration fineness. Depending on the filter aid used and the dirt content of the medium to be filtered, filter fineness between 3 and 10 µm can be achieved. After the precoating process, the actual filtration starts automatically. When the maximum filtration time is reached, the filter elements are completely cleaned by an automatic backwash and are available for a new cycle.

3D image of a precoat filter system with FAUDI logo

Precoating

The filter pump takes the dissolved mixture of filter aid and clean medium from the precoat tank and applies it to the filter cartridge. The mixture flows through the filter cartridges from the outside to the inside. This precoating process is carried out until a sufficient layer of filter aid has built up on the cartridge.

Filtration

During filtration, the contaminated medium is taken from the dirt tank after the precoating process, applied to the filter elements and flows through from the outside to the inside. During the filter cycle, the dirt particles accumulate on the precoat layer.

Regeneration

When the maximum differential pressure between the dirty and clean sides of the filter is reached or a preset filtration time is reached, automatic regeneration or backwashing is initiated.