Outotec Screen SAF Series filters are easy to operate, with an automatic self-cleaning mechanism driven by an electric motor. Their large filter area, reliable operating mechanism, and simple, robust construction make them perfect for filtering poor quality water to very fine filtration degrees. Available with inlet/outlet diameters of 2–10” and supporting flow rates of up to 400 m3/h (1,760 gpm), they are ideal for numerous applications and industries.
Automatic flushing according to pressure differential and/or time
Flushing does not interrupt downstream flow
Minimal reject water volume allows excellent operation in continuous flush mode
Low cleaning water consumption (less than 1% of total flow)
The filtering process
Raw water enters the filter inlet through the coarse screen, which protects the cleaning mechanism from large debris. The water passes through the fine screen, trapping dirt particles which accumulate inside the filter. Clean water flows through the filter outlet.
The gradual dirt build up on the inner screen surface causes a filter cake to develop, with a corresponding increase in the pressure differential across the screen.
A pressure differential switch senses the pressure differential and when it reaches a pre-set value the cleaning process begins.
The self-cleaning process
Filter cleaning is carried out by the suction scanner, which spirals across the screen. The open exhaust valve creates a high-velocity suction stream at the nozzle’s tip that vacuums the filter cake from the screen. During the self-cleaning process, which takes from 20 to 40 seconds, filtered water continues to flow downstream.
The control system
Two types of control boards are available for SAF filters: PLC or electromechanical relay and timer.
The self-cleaning cycle begins under any one of the following conditions:
Receiving a signal from the pressure differential switch
Time interval parameter set at the control board
The control board also provides:
Optional continuous flush operation mode
Alarm output – may be used to open a bypass, shut off a pump, etc.
The Outotec Screen SAF Series range consists of the following models:
SAF-1500 for flow rates of up to 80 m3/h (350 gpm)
SAF-3000 for flow rates of up to 150 m3/h (660 gpm)
SAF-4500 for flow rates of up to 250 m3/h (1,100 gpm)
SAF-6000 for flow rates of up to 400 m3/h (1,760 gpm)