INTRODUCTION
MANOWNROLH
1-2
U.S. FILTER
Quality audits do not improve products. They do, however, insure that a system meets
or exceeds specifications required for your system.
In the Appendix is a copy of our Quality Control form for your system.
1.3
FUNCTIONS OF THE SYSTEM COMPONENTS
A.
Reverse Osmosis Membranes
The prefiltered water enters the RO housing and passes over the surface of an
RO membrane. A portion of the input water continues out of the system through
a reject needle valve. The remainder of the water permeates the membrane and
is directed to an accessory storage reservoir or point of use. Percent conversion
(the ratio of RO product water to feedwater) will vary depending on water quality
and the application. The reject needle valve and the pump throttle valve are
adjusted to provide the proper permeate flux and transmembrane differential
pressure. The permeate flux is also a function of temperature.
B.
Reverse Osmosis Pump
The RO system contains a centrifugal pump driven by an AC motor. The pump
motor is turned on and off by a motor starter relay and will not operate when the
pump inlet pressure is less than .69 bar (10 psig). The pump motor starter also
contains an overload relay.
C.
Pressure Switch
If the pressure on the pump suction falls below .69 bar (10 psig) a pressure
switch automatically shuts off the pump motor to prevent damage to pump. The
low pressure switch will not be activated with momentary pressure drops of less
than 3 seconds during normal system operation.
If the pump discharge pressure exceeds 20.7 bar (300 psi) a pressure switch
automatically shuts off the pump motor to prevent damage to the pump.
If the system experiences a pressure switch shutdown the condition should be
corrected. The system is manually restored to operation by pressing the reset
button on the control panel.
D.
Reject Recirculation (optional)
If the system is provided with the reject recirculation option, it permits part of the
reject water to be returned to the inlet of the high pressure pump. This increases
percent conversion of the system.
E.
Auto Flush (optional)
A throttle valve restricts the flow of water through the reject line to maintain
proper reject flow. In the "TANK FEED" and "STANDBY" modes, an optional
solid state timer automatically opens the reject solenoid valve for one minute
every hour, bypassing the throttle valve. The flush time is also programmable to
2 or 4 minutes if the water quality is poor and has a tendency to plug the
membranes necessitating longer flush times. During this time, a high velocity
flush of water sweeps through the matrix of the RO membrane to prevent the
accumulation of scale (carbonate deposits) or other contaminants that tend to
collect on the surface of RO membranes. A new flush cycle begins each time the
system is turned on. The flush cycle is inhibited during the "DIRECT FEED"
