TECHNOLOGY NOTE 27

PureSure® System used inPURELAB® Chorus 1
Extending the life of the purification packIn a conventional water purifier, when a purification pack, fed
with RO permeate with a conductivity of about 35 µS/cm at 1.5
to 2 liters/minute has reached the stage when output water
purity drops below 18.2 MΩ-cm, it is necessary to change thepack, in order to maintain water purity. At this point, only about
40 to 45% of the resin’s total ion exchange capacity has beenused up.
The capacity advantage of the PURELAB Chorus 1 system isillustrated in Figure 1 where in a conventional water purifier thepack would have to be changed after 880 liters when the productwater resistivity had dropped to 17.5 MΩ-cm.
In the PURELAB Chorus 1, the first purification pack is used until
its output purity has decreased to 1 MΩ-cm, using about 80% of
the total pack capacity, 1590 liters in the example shown. Output
purity from the system is maintained at 18.2 MΩ-cm by thesecond purification pack.
Over 80% greater utilization of resin capacity is achieved by thismeans. The relative gain depends on the purity of the feedwaterand the flowrate. The poorer the feed purity and the faster theflow, the smaller the proportion of primary purification packcapacity that is used before the output purity drops below
Figure 1:

18.2 MΩ-cm and the greater the capacity advantage with thePURELAB Chorus 1. The PURELAB Chorus 1 enables a high output
flow rate of 2.0 liters/minute to be achieved with high resin
enhanced capacity utilization.
When the purity of the output from the first purification packhas fallen to 1 MΩ-cm the first pack is still removing over 95%of the ions from the feed (with a conductivity of 20 µS/cm orgreater). The second pack is only removing the remaining few% of ions. The overall effect is that less than 5% of the polishingpack’s capacity is used in gaining 80% extra from the primary
purification pack.
This is demonstrated in Figure 2 which shows the water purityin MΩ-cm against usage in thousands of liters for both aPURELAB Chorus purification pack, which was fitted new in theprimary pack position, and a pack which was first used in thepolishing position. If the capacity of the polishing pack had beensignificantly used, then one would have expected to find thecapacity curve shown to be significantly to the left of that of thenew pack. In practice they are virtually identical, confirming thatuse of the pack in the polishing position has a negligible effecton its capacity and that the extra capacity achieved from theprimary purification pack is fully realised.
Figure 2:

Product Resistivity Profile of PURELAB Chorus 1

1818161614121086414121064200400

800

1200

Volume (Liters)

1600

2000

Pack from 2nd Position
New pack

820

Feed : 37 µS/cm, 1.8 l/min

20

Resistivity (MOhm.cm)

Resistivity (MOhm.cm)

Sodium chloride Capacity of PURELAB Chorus 1

Feed : NaCI 37 µS/cm, 1.8 l/min

20010000

20000

30000

40000

50000

Liters at 1 µS/cm

ELGA LabWater
Tel: +44 (0) 203 567 7300 Fax: +44 (0) 203 567 7205 Email: info@elgalabwater.com Website: www.elgalabwater.com
ELGA® is the global laboratory water brand name of Veolia Water Technologies. VWS (UK) Ltd. Registered in England & Wales No. 327847 © Copyright 2014 ELGA LabWater/VWS (UK) Ltd.
All rights reserved. As part of our policy of continual improvement we reserve the right to alter the specifications given in this technology note. Technology Note TN27.

60000