Outotec Screen EBS Series filters are large, self-cleaning automatic filters for fine filtration. Their large filtration area, reliable electric mechanism, and simple, robust construction make them perfect for filtering high-flow and poor quality water to very fine filtration degrees. Available with inlet/outlet diameters of 8”–36” and supporting flow rates of up to 7,200 m³/h (32,000 US gpm), they are ideal for a wide range of 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 flush mode
Low cleaning water consumption (less than 1% of total flow)
The filtering process
Raw water enters from the filter inlet (1) and passes through the screen (2). Clean water flows through the filter outlet (3). 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 (4) 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 (5), which spirals across the screen. The open exhaust valves create a high-velocity suction stream at tip of the nozzles that vacuums the filter cake from the screen. During the self-cleaning process, which takes approximately 30 seconds, filtered water continues to flow downstream.
The control system
The filter operation and cleaning cycles are controlled and monitored using a programmable logic controller (PLC). The PLC allows maximum flexibility in control options and has many additional features that can be incorporated according to customer need. During the self-cleaning cycle the PLC controls a solenoid that operates the exhaust valve by means of a hydraulic command or compressed air.
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.