Close view of a fully automatic backwash filter

Backflush filters

Filtration solutions for the preparation of water-miscible
and non-water-miscible cooling lubricants.

Backwash filter -Rendering3

Cartridge filter systems:

Backflush filters
(RSF)

The FAUDI backflush filter is suitable for the filter aid-free filtration of water-based and non-water-based cooling lubricants and oils. The backflush filter is used in machining operations such as turning, drilling and milling. The filtration capacity depends on the filter size and the filter medium. However, due to the modular design of the backwash filter, the filtration capacity can be individually adjusted from 250 l/min to 20,000 l/min.

Interior of a backwash filter, where individual filter cartridges can be seen — Backwash filter -Rendering4

How does a
Backflush filter work?

A backflush filter type RSF is divided into a lower dirt chamber and an upper clean chamber by a flanged, perforated insert plate sealed against the vessel wall. Several cylindrical filter cartridges are arranged on the holes (the number of cartridges depends on the application). The contaminated medium flows into the filter through the inlet flange, flows through the filter cartridges from the inside to the outside and exits again as clean medium through the outlet flange. Carried air and gas components are separated by a vent valve, while the dirt particles are retained inside the filter element. The impurities accumulate on the smooth, inner surface of the filter cartridges and form a cake. This growing dirt cake causes a continuous increase in the pressure difference between the dirty and clean sides. This pressure difference activates the self-cleaning process by backflushing by a contact manometer and a corresponding control system. For cleaning the filter cartridges, a movable backflushing arm, which is driven by an electric motor, approaches all the filter cartridges one after the other from the bottom. During the cleaning process, cleaned medium flows through a filter cartridge in the opposite direction to the filtration direction and removes the adhering impurities. These are discharged through the dirt drain. The limitation of the backflush loss is controlled by a shut-off valve in the backflush line. One filter cartridge is always being cleaned, while the other filter cartridges remain in the filtration process. The result is automatic cleaning without interrupting filtration.

Grey backwash filter with FAUDI logo on white background

Filtration:

The medium which has to be filtered flows through the filter cartridges from the inside to the outside. Contaminants are retained on the inside of the smooth surface, while the sharp edges and precision of the triangular profiles minimize the tendency to clog.

Backflush:

The filtered product flows through the filter cartridges from the outside to the inside. The nozzle effect created by the V-profile at the slit-tube filter cartridges also flushes colloidal contaminants back from the smooth filter surface.

Benefits: Your advantages
at a glance

Machining quality through guaranteed
filter fineness
Low emission and constant cooling lubricant quality through predominantly closed system
Future-oriented due to easy removal of the filter surface
Several filtrate qualities can be realized with a single filter system