18 Jun THE IMPORTANCE OF SAFETY FILTERS BEHIND MEDIA STATIONS
THE IMPORTANCE OF SAFETY FILTERS BEHIND MEDIA STATIONS
All media filters are equipped with a system for retaining the grains that are used at the filtered water outlet channel. These components can either take the form of grooved cylindrical arms (collector arms) or nozzles, also grooved. These devices are responsible for ensuring that the grains are not expelled from the filter.
Each media filters contain granular material. Despite the fact that maximum and minimum grain sizes are guaranteed, smaller particle content should not be ruled out. To prevent these small particles from being expelled from the filter and getting into the clean water system, a safety filter, consisting of either parallel discs or screen, is installed behind stations fitted with media filters.
These safety filters also have a secondary role of retaining grains if the collector arms or nozzles inside the bed filter fail.
The screen or disc safety filters can be cleaned manually or automatically. Nowadays these filters tend to be automated to facilitate cleaning, as well as to specify the precise moment that they should be cleaned. Two sensors are used for all automatic cleaning systems, a maximum and a minimum sensor, to provide information to the programmer and to start the cleaning stage. Valves used to discharge the dirty water are operated with a solenoid, which receives information from the programmer.
A media filter system is incomplete if its outlet is not fitted with a disc or screen-based safety system.
LAMA always recommends that media filter equipment should never be installed without these filters, as they provide evidence of irregularities and/or accidents inside the device.