Rain Bird C+ SERIES Operation And Maintenance Manual - page 6
4
BACKWASH CYCLE
The controller opens the flush valve, which causes a drop in pressure in the
hydraulic motor chamber. This creates a low pressure path inside the particle
remover, which acts as a vacuum at the end of the suction nozzles, removing the
built up debris from the inside of the fine screen.
C+ SERIES FILTER - BACKWASH CYCLE
FLUSH
HYDRAULIC MOTOR CHAMBER
(LOW PRESSURE)
INTERIOR OF FILTER
(HIGH PRESSURE)
Water flows through the suction nozzles, down the interior of the particle
remover, and out the hydraulic motor. The motor rotates the particle remover,
enabling each suction nozzle to cover a radial strip of screen. The pressure
difference between the interior of the filter and the hydraulic motor chamber
drives the particle remover toward the hydraulic piston.
The piston depressurizes during the backwash cycle, and expels the volume of
water from its chamber. This acts as a timer, gradually allowing the particle
remover to drive the piston rod into the piston, assuring that the suction nozzles
cover the entire surface of the fine screen. When the piston reaches the end of
its stroke, the backwash cycle is complete, and the flush valve closes. Pressure
inside the hydraulic motor chamber normalizes, and the piston pushes the
particle remover back to its original position.
After the piston and particle remover move back to their original positions, the
filter returns to normal operation. During the entire backwash cycle, the main flow
through the filter is never disrupted.