ORE/A Electric Automatic Self-Cleaning Screen Filters
www.orival.com
Key features include:
- No troublesome limit switches
- Single direction fractional horsepower electric motor
- No reversing contactors
- Simple controller
- User can set any number of passes by the dirt collector during each rinse cycle
- 2" to 8" filter models use only a single 1½" rinse valve so rinse flow and volumes are small
- Larger filters use a single 2" or 3" rinse valve
- Self-adjusting nozzles maintain light contact with the multi-layer screen surface during rinse cycles to maximize screen cleaning and minimize rinse water to drain
How It Works
Dirty water enters the inlet flange (1) then passes through the coarse screen (2) from outside-in removing large hard objects. The pre-screened water then flows to the inside of the multi-layer fine screen (3). As water passes from inside-out in the fine screen, suspended solids are stopped if they are too large to pass through the screen openings. Clean filtered water then leaves the filter through the outlet flange (4). As more and more material builds up on the inside surface of the fine screen a pressure drop in the system begins to build. When a preset pressure drop threshold is reached across the fine screen, the controller is signaled to initiate a cleaning cycle. The first step in the cleaning cycle is to open the rinse valve (5) to atmospheric pressure which quickly drops the pressure in the rinse chamber (6). Because the hollow dirt collector (7) connects the end openings in the nozzles (8) to the flush chamber, water quickly moves from the nozzle opening (8), thought the dirt collector (7) into the flush chamber (6) and out the rinse valve (5) to a drain. Since the self-adjusting nozzles allow each nozzle opening to touch the screen surface, water rushes backward through the screen (outside-in) in a small area about 15 mm in diameter at a velocity exceeding 50 ft/sec (15 m/sec). This intense energy sucks off the stickiest material and expels it from the system though the rinse valve (5). The gearmotor drive assembly (9) then slowly rotates the dirt collector. A positive mechanical device causes the dirt collector to slowly move linearly while rotating. The slow spiral movement of each nozzle (8) on the dirt collector (7) assures that every square inch of fine screen surface is vacuumed clean of all debris in 20 to 30 seconds. The reversing mechanism allows the dirt collector to oscillate back and forth as long as the single-direction motor is operating. There are no limit switches to fail or multiple motor starters and overload protectors in the control box. The controller stops the drive assembly (9) when the screen is clean and closes the rinse valve (5) completing the cleaning cycle. The next cleaning cycle will begin when the pressure drop threshold is met again or until a preset time interval has been reached.
Exploded View of ORE/A
www.orival.com