The backwash filter automatically opens the backwash circuit in the cleaning unit if the pressure difference exceeds the specified limit or the time interval has passed. Due to the rotation of the cleaning unit, part of the filtered product flows through each filter element from the outside in turn, and through the reverse flow washes impurities away from the smooth filter surface. The backwash medium is washed away through a separate connection. The actual filtration process is not interrupted during backwashing.