1-14. COMPONENT TECHNICAL PRINCIPLES OF OPERATION - continued.
unfiltered water (brine) flows out of the ROWPU for storage in the backwash water tank Pure water flows out of
the center of each pair of filter elements into a common pipe that carries the water out of the ROWPU for storage
in the product water tanks. Connections between pressure vessels in models WPES-2 and WPES-3 are different
than model WPES-, but operation is identical.
ab. R 0. Vessels Gage (28). Indicates differential pressure across the R.O elements
ac. Brine Flow Meter (29). Indicates rate of brine flow out to backwash water tank
ad. Backwash Water Tank (30) Collects water rejected by R O elements (brine) for use in backwashing multimedia
and in cleaning the R 0 elements.
ae. Backwash Tank Value (31) Controls flow of brine from backwash water tank.
af. Backwash Pump (32). Forces brine backward through multimedia filter during backwash. Output of multimedia
filter is dumped out of ROWPU through WASTE hose. When backwash cycle is complete, output of backwash
pump is connected to VENT VESSELS line Brine mixed with citric acid is then forced through R.O. elements to
clean them. The solution is returned to backwash water tank and recirculated by backwash pump. Product water
is sent to backwash water tank during this procedure to keep the citric acid solution from becoming concentrated.
ag. Backwash Pump Strainer (33). Filters brine before it enters multimedia filter or R.O elements.
ah. Backwash Water Flow Gage (34) Indicates rate of brine flow into multimedia filter during backwash.
ai. Check Valve (35). Prevents raw water from entering backwash water line.
aj. Vent Vessels Valve (36). During ROWPU startup, bypasses R.O. pump output around R 0. elements until
multimedia filter stabilizes. During element cleaning, passes brine/citric acid solution from backwash pump to
ak. Product Water Sample Ball Values (37). Provide samples of filtered water at input ends of pressure vessels.
al. Product Water Sample Elliptic Valves (38). In normal position, pass product water out of R 0. elements to
product water tanks. In sample position, direct product water of out each R.O. vessel as a sample Design
prevents shutdown of water flow while switching between normal and sample positions.
am. Chemical Feed Meter Pump Chlorine Drive Unit (39) Adds chlorine to product water to prevent bacteria growth.
an. Regulate Product Flow Value (40) Controls rate of product water flow to product water tanks.