Checking The Concentrate To Purified Water Ratio - SpectraPure MaxPure MPDI RO/DI System Installation And Operating Manual

SpectraPure
Membrane Output Calculation
Membranes produce the rated gallons per day (GPD) at 60 psi (4.1 bars) operat-
ing pressure, 77°F (25°C) operating temperature and 500 ppm total dissolved
solids.
Membrane output gallons per day (GPD) depends on operating pressure, water
temperature and the ppm TDS in the feed water.
Expected GPD = Rated GPD × PCF × TCF
PCF is the pressure correction factor
TCF is the temperature correction factor
Calculation of Pressure Correction Factor (PCF):
the membrane is directly proportional to the applied pressure.
Note: The membrane is rated to produce the rated GPD at 60 psi. For any
pressure other than 60 psi the output GPD is multipled by the PCF.
PCF = Line Pressure (in psi) ÷ 60
Calculation of Temperature Correction Factor (TCF):
also decreases with decrease in temperature. This is because water viscosity
increases with decrease in water temperature.
Temperature Correction Factor Table (TCF)
°F /°C TCF °F \°C
41.0 /5 0.521 59.0 /15
42.8 /6 0.540 60.8 /16
44.6 /7 0.560 62.6 /17
46.4 /8 0.578 64.4 /18
48.2 /9 0.598 66.2 /19
50.0 /10 0.620 68.0 /20
51.8 /11 0.640 69.8 /21
53.6 /12 0.661 71.6 /22
55.4 /13 0.684 73.4 /23
57.2/14 0.707 75.2 /24
SpectraPure®Inc.
480.894.5437 Call us toll-free 1.800.685.2783
215 South Industrial Drive, Suite 2A Tempe, Arizona 85281-2941
18
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Membrane Testing
The output (GPD) from
The output (GPD)
TCF °F \°C TCF
0.730 77.0 /25 1.000
0.754 78.8 /26 1.031
0.779 80.6 /27 1.063
0.804 82.4 /28 1.094
0.830 84.2 /29 1.127
0.857 86.0 /30 1.161
0.884 87.8 /31 1.196
0.912 89.6 /32 1.232
0.941 91.4 /33 1.267
0.970 93.2 /34 1.304
SpectraPure

Checking the Concentrate to Purified Water Ratio

This procedure will assure you of maximum life and reliability of
your SpectraPure System.
Failure to perform this procedure can permanently damage the
membranes and will void the pro-rated Membrane Warranty.
In order to maximize the life of your SpectraPure RO Membrane, you
may need to adjust the ratio of the concentrate to purified water.
If not enough concentrate is allowed to flow past the membrane
during operation, the impurities will precipitate out on the mem-
brane surface, clogging the RO Membrane. To keep this from hap-
pening, the Concentrate to Purified Water Ratio must be checked
and adjusted in order to compensate for pressure and temperature
variations that exist in all water supplies. The flow rate of the concen-
trate must be a minimum of 4X the product flow rate. 4X to 6X is an
acceptable concentrate flow rate.
Procedure:
1. Open the cold water supply valve and let the system run for
15 minutes.
2. Collect product water from the blue tubing into a measuring
cup for two minutes. Measure the collected amount in milli-
liters and divide by 2. The resultant is the product flow
rate in Milliliters per Minute.
(Although not needed in this proceedure, the daily product
flow rate in Gallons per Day (GPD) can be calculated to be
equal to the product flow rate times 0.38 ).
3. Use the procedure and tables on the following pages to
determine the optimum length of the flow restrictor capillary
tubing. After adjusting the flow restrictor, repeat the above
procedure and recheck the Concentrate to Purified Water
Ratio.
SpectraPure®Inc .
Fax 480.894.6109 Fax us toll-free 1.877.527.7873
E-mail: spectra@spectrapure.com Visit us on the web www.spectrapure.com
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System Set-Up
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