Puricom Europe ZIP, User Manual, Page: 5 / 17

ZIP / User manual / 2. Introduction
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2. Introduction / User manual / ZIP
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How to tell if the RO membrane needs replacement:
The condition of the membrane is assessed by testing the percent
TDS rejection:
90 - 95% > MAXIMUM QUALITY
70 - 80% > LOW QUALITY
80 - 90% > MEDIUM QUALITY
Using a TDS meter, compare the TDS of the inlet water to the pure
RO water, and obtain the percentage of TDS rejection.
% Rejection Rate = x
TDS of inlet water-TDS of pure water
(
)
If rejection goes below 70%, the membrane life has come to an
end.
2.4 Effect of pressure and temperature in a RO sys-
tem.
The percentage salt rejection of the membrane is normally more than
95%, but depending on the water quality, temperature and pressure,
the percentage may vary.
Pressure (Bar)
0,70
1,00
1,50
1,75
2,50
4,00
4,50
4,90
5,20
5,80
Salt rejection (%)
84
88
90
92
93
95
95
95
95
95
FACTOR CONVERSION
FOR PRESSURE
About production
0,17
0,25
0,33
0,42
0,58
1,00
1,08
1,17
1,25
1,42
CONVERSION FACTORS
CONVERSION FACTORS
TEMPERATURE
Temperature (ºc)
6
8
10
12
14
16
18
20
22
25
28
30
32
34
About the production
0,38
0,45
0,52
0,59
0,66
0,70
0,77
0,85
0,88
1,00
1,09
1,16
1,23
1,30
TDS of inlet water