Backwash Valve Operation
Valve actuation is accomplished hydraulically, using water internal to the filter system. The water is drawn-off the inlet manifold, through a strainer, and into poly tubing, which is connected to each of the filters in the system.
When the backwash cycle is initiated, the following occurs:
The backwash control unit sends a signal to the solenoid valve, that is attached to the actuator cover of the first filter in the system. ( Once the first filter is backwashed, the control will send a signal to the solenoid valve on the second filter, and the thereafter to each filter in turn, until all in the system have been backwashed ).
The port on the solenoid valve moves from the closed to the open position.
The poly tubing which is attached to the solenoid allows water from the inlet manifold to pass through the solenoid and into the actuator housing.
As water enters the actuator housing, the hydraulic pressure moves the piston and rolling diaphragm forward, causing the backwash shaft to also move forward.
As the backwash shaft moves forward it also drives the valve plates and seal forward until they close off the inlet port of the valve. This prevents water in the inlet manifold from entering the filter.
As the inlet port of the backwash valve is closed, the backwash port is simultaneously opened. This allows the backwash water coming up through the media bed to carry debris, out the top of the filter, through the backwash port and into the backwash manifold.
When the end of the Flush Time has been reached, the valve is de-energized. The water in the actuator housing drains out of the housing and out through the exhaust port on top of the solenoid valve. The water is carried away from the solenoid via poly tubing.
As the hydraulic pressure inside the actuator housing decreases, the piston and diaphragm return to their normal position, causing the valve plates and seal to open the inlet port on the backwash valve and close the backwash port.
With the reopening of the inlet port, the filter will return to the filtration mode, and this same process will be repeated one at a time with the other filters in the system.
To discuss more information regarding Everfilt® Water Filtration Systems, talk with an Everfilt® Applications Engineer: 1.800.360.8380 / everfilt@everfilt.com