Orival OR-02-PE, Operation And Maintenance Manual, Page: 45 / 51

ORIVAL, INC. • 213 S. Van Brunt St. • Englewood, NJ 07631 • (201) 568-3311
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12.2 Using a Controlled Outlet Valve (COV)
A Controlled Outlet Valve (COV for short) is a valve installed after the outlet of the filter,
and is used to control the flow through the filter during the rinsing cycle. A COV is used
when inlet pressures are low or drop below the 30 psi minimum with the rinse valves
open. In most cases, the Controller will activate the COV prior to rinse valve activation.
This throttles the flow out of the filter’s outlet, to develop more inlet pressure to better
provide adequate pressure for a proper rinse.
A COV is installed on the outlet leg of the filter, usually before the outlet isolation valve.
For multiple filter installations, the COV is located at a point on the main line after the
multiple filter outlets are rejoined. The drawings on page 40 show typical filter
installations with a COV installed.
12.3 Using an External Source of Rinse Water & a COV
There are installations where there is insufficient pressure or flow to properly perform a
rinse cycle. This can sometimes be overcome by the use of a COV and an external
source of water with sufficient pressure and flow. For these installations, a COV is
installed as described in section 12.2, above, and an external water source is connected
in the inlet area of the filter. To further enhance rinse performance, the two-stage
pressure manifold is relocated on the external water source line. When a rinse cycle is
required, a valve on the external source line is opened as the COV is closed. The filter’s
flow to the outlet is stopped and the higher-pressure external source water is used to
clean the filter. Once the COV is closed and the external water line opened, then the
rinse cycle is initiated by energizing the solenoid relocated on the external source line
along with the two-stage manifold. At the end of the rinse, the rinse solenoid is de-
energized, the COV is opened and the external source valve is closed to return the filter
to normal operation. The drawings on page 41 show typical external water source
installations including a COV, external source control valve and two-stage manifold with
rinse solenoid moved to the external source line. These drawings also show check
valves on the inlet and external water lines. These valves are highly recommended to
prevent flow or contamination problems.
12.4 Water Hammer Solutions
Water hammer is a natural phenomenon that can be present in typical water filtration
installations. It occurs as a result of the rapid flow of dirty rinse water from the rinse
valve(s) suddenly being stopped as the rinse valve(s) close at the end of the rinse cycle.
The results range from a soft tap to a loud bang that echoes throughout the drain line.
ORIVAL has had some success in reducing this offensive noise by adding vacuum
breaker valves to the drain lines. Two valves are added to the tops of the ½’’ pipe
columns extending above each of the drain lines. See page 42 for a typical installation.