Watts R48-20-3131100 User Manual
Page 7
The effect of suspended solids is measured by the silt density index (SDI) test. An SDI of five or
less is specified by most membrane manufacturers and three or less is recommended.
Iron & Manganese - These foulants should be completely removed (less than 0.1 ppm). Special
media filters and/or chemical treatment is commonly used.
pH - pH is often lowered to reduce the LSI. The membranes have a pH operating range of 2-11.
Silica: Reported on the analysis as SiO2. Silica forms a coating on membrane surfaces when the
concentration exceeds its solubility. Additionally, the solubility is highly pH and temperature
dependent. Silica fouling can be prevented with chemical injection and/or reducing the recovery.
II.
CONTROLS, INDICATORS, and COMPONENTS (see figure 1)
A. Controller - Controls the operation of the system and displays the product water
quality.
B. Reject Control Valve - Controls the amount of reject flow.
C. Reject Recycle Control Valve – Controls the amount of reject recycle flow.
D. Pump Discharge Valve - Used to throttle the pump.
E. Prefilter Inlet Pressure Gauge - Indicates the inlet pressure of the prefilter.
F. Pump Suction Pressure Gauge – Indicates the prefilter outlet and pump suction
pressure. The difference between this gauge and the prefilter inlet gauge is the
prefilter differential pressure of the prefilter.
G. Pump Discharge Pressure Gauge - Indicates the pump discharge pressure.
H. Membrane Feed Pressure Gauge – Indicates the membrane feed pressure.
I. Reject Pressure Gauge - Indicates the reject pressure.
J. Reject Flow Meter - Indicates the reject flow rate in gallons per minute (gpm).
K. Reject Recycle Flow Meter – Indicates the reject recycle flow in gpm.
L. Product Flow Meter - Indicates the product flow rate in (gpm).
M. Prefilter Housing - Contains the RO prefilters.
N. Automatic Inlet Valve - Opens when pump is on and closes when the pump is off.
O. RO Feed Pump - Pressurizes the RO feed water.
P. RO Membrane Vessels - Contains the RO membranes.
Q. Motor starter / transformer enclosure.