Backflush filters and their function at a glance

What is a backflush filter and how is it constructed?

An automatic backflushable filter is a self-cleaning filter that works continuously without interrupting operation. In contrast to conventional filters, which have to be replaced regularly or cleaned manually, this backflush filter uses an automatic cleaning mechanism. The accumulated dirt is removed from the filter elements by a targeted backflow of the cleaned medium.

The FAUDI backflush filter type RSF is divided into a lower dirt chamber and an upper clean chamber by a flange-like, perforated insert plate sealed against the tank wall. Several cylindrical filter cartridges are arranged on the insert plate, and the number depends on the size and application. In concrete terms, backflush filters work via the following components:

• Filter inlet and outlet: This is where the medium enters the filter and is discharged again after filtration.
• Filter cartridges: Cylindrical filter elements that retain particles and dirt.
• Backwash arm: A mechanical device that controls the backwashing process of the filter cartridges.
• Backwash outlet: This is where the detached contaminants are discharged.
• Residual emptying: Enables the dirt chamber to be emptied completely.
• Gear motor: Drives the backwash arm to clean the filter elements in a targeted manner.

How do backflush filters work? How they work in detail

A backflush filter works according to a proven principle to ensure efficient filtration with simultaneous self-cleaning:

1. Filtration process:
   The medium to be cleaned enters the filter through the inlet flange. There it flows from the inside to the outside through the filter cartridges, whereby the particles are retained. The cleaned medium leaves the filter through the outlet flange.
2. Particle separation:
   During filtration, dirt particles settle on the smooth, inner surface of the filter cartridges and form a so-called dirt cake.
3. Pressure difference as an indicator for cleaning:
   The increasing layer of particles leads to an increasing pressure difference between the dirty and clean side of the filter. As soon as a certain threshold value is exceeded, a contact pressure gauge automatically activates the backwashing process.
4. Automatic cleaning by backwashing:
   1. A rotating backwash arm, driven by a geared motor, moves the filter cartridges one after the other from below.
   2. After opening the backwash fitting, cleaned medium flows in the opposite direction through the filter cartridges, whereby the impurities are detached and discharged through the backwash connection.
   3. At the end of the backwash, the geared motor stops and the backwash valve closes.
5. Uninterrupted filtration:
   The decisive factor for the efficiency of a backwashable filter is that only one filter cartridge is rinsed at a time during cleaning, while the others continue to filter. This ensures that the filtration process remains active throughout.

Convincing advantages for various industries

The use of an automatic backflush filter offers many advantages: It ensures efficient operation without manual maintenance, saves costs thanks to the long service life of the filter elements and reduces media loss. The technology has proven itself particularly well in water treatment, the chemical and pharmaceutical industries, food production and metal processing. Backwashable filters also make an important contribution to the purity of process fluids in oil and fuel filtration.

Conclusion: Ecological, economical and flexibly configurable

The backflush filter function enables reliable, self-cleaning filtration without interrupting operation. Automatic cleaning significantly extends maintenance intervals, which saves costs and resources. Whether in the oil industry, water treatment or food production – a backwashable filter from FAUDI is the ideal solution for numerous applications.

Contact us now