How the SAF Filters work
The Amiad SAF Series are sophisticated, yet easy-to-operate, automatic filters, with a self-cleaning mechanism driven by an electric motor.
The "SAF" filters support flow-rates of up to 400 m³/h (1760 gpm), with various screens designed to cover a range of 800-10 micron filtration degree, and are available in inlet/outlet diameters of 2"-10".
The Filtering Process
Raw water enters the filter inlet (1) through the coarse screen (2) which protects the cleaning mechanism from large debris. The water passes through the fine screen (3), trapping dirt particles which accumulate inside the filter. Clean water flows through the filter outlet (4).
The gradual dirt buildup 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
Cleaning of the filter is carried out by the suction scanner (5) which spirals across the screen; the open exhaust valve creates a high velocity suction stream at the nozzles tip which "vacuums" the filter cake from the screen. During the self-cleaning process, which takes between 20 to 40 seconds, filtered water continues to flow downstream.
The Control System
Two types of control boards are available for the SAF filters: PLC or Electro-Mechanical Relay and Timer.
The self-cleaning cycle begins under any one of the following conditions:
- Receiving a signal from the Pressure Differential Switch (6)
- Time interval parameter set at the control board
- Manual Start
The control board also provides:
- Optional continuous flush operation mode
- Flush cycles counter
- Alarm or an alternative reaction at malfunction mode; open a bypass, shut-off a pump, etc.