Taking advantage of the existing line pressure on the outside of the filter elements, one provokes the same instant flux reversal, and the previous debris retained in the filter septum, flushed to the drain in a time of 3 to 5 seconds, this time adjusted According to the need, consuming minimal product filtered to backwash. Due to the large filtering area and free passage of the liquid through the equipment, the head loss introduced into the line in the clean filter condition, is extremely low. (Negligible). During normal filtering process, it creates the progressive increase in pressure drop between the input and filter output due to clogging of the surface by solid retained, with consequent reduction of the free area and differential pressure increase between input and output. At a pre-determined level of acceptable charge loss at 3.5 mwc case, between the inlet and outlet chambers, an electronic sensor differential pressure (P1) in the range 0.1 to 1.0 atm commands backwashing process individually and sequentially for all the filter elements, without interrupting the main flow as described above, replacing the filter to completely clean condition. The thorough washing time is at most about 2 minutes.