Disc filtration technology is relatively young in comparison with traditional backfill and mesh filters, but during its existence it has managed to prove itself from the best side, to show its advantages and to win the trust of consumers.
The main advantages of disc technology over traditional methods of filtration (mesh and backfill):
Operating principle of disc filtration systems with automatic flushing
The filter elements are based on a cassette of compressed polypropylene discs with microchannels, which in the compressed state form a depth filter element. The advantage of these elements is that they are not subject to wear for many years (about 10 years). In case of contamination, the discs are washed by unclamping, fully restoring their filtering capacity.
These systems are automatically flushed and have different modes and programming options. In normal mode, the station is flushed when the set differential pressure drop is reached on the differential pressure gauge with which the system is equipped. It is also possible to set flushing modes by time intervals, regardless of the degree of contamination.
The disc filter units are housed in a plastic case. The discs are colour coded: the colour indicates the fineness of filtration provided by the given set of discs.
The system is made up of the number of filters required for a given water flow rate, connected via control valves to the inlet, outlet and drain manifolds.
The source water is fed through a flanged port into the inlet manifold of the system. The water flow is then divided according to the number of filters installed in parallel and, via control valves, is fed to the disc filter elements. After passing through the filter elements, the treated water flows are summarised in the outlet manifold of the unit.
In the filtration mode, the filter element discs are compressed by the spring force and the component of hydrodynamic force arising when the water flow passes through the filter channels. The compressed discs constitute a single filtering volume.
The advantage of disc filtration systems in comparison with mesh systems is that the mesh has a small filtering surface and consequently dirt capacity (filtration is only surface), and the disc element, due to the combination of surface and depth filtration, is able to retain a much larger amount of mechanical impurities before the next washing. The maximum pressure drop on these systems before the next regeneration is 0.5 Bar. At this differential pressure drop, the modules are automatically rinsed one by one without interrupting the supply of purified water to the consumer through the entire filter.
Automatic filter backwashing.
Backwashing starts when a signal is received from the controller. Filter modules are washed alternately. Valves change the direction of water flow through the module being washed to the opposite one, at the same time the pack of discs is unclamped, releasing all trapped impurities. Under the action of tangential water flow created by special nozzles inside the filter, the discs start to rotate and all particles from the surface of the discs are quickly and efficiently washed into the drain under the action of reverse water flow and centrifugal forces. Flushing is carried out with filtered water from neighbouring modules. Filtration systems are always designed to ensure that the flow rate of clean water required by the user is maintained even during flushing.
Examples of installed systems.
