Purpose Of The Product - BWT STANDARD Installations- Und Anwendungshandbuch

1. PURPOSE OF THE PRODUCT

Reverse osmosis is by far the most advanced technology of water purification in use today.
Special semipermeable membrane structure similar in its properties to the membrane of a
living cell is capable of purifying drinking water from virtually all harmful impurities (see Fig-
ure 1). The membrane can be conceived of as having tiny pores, 200 times smaller than vi-
ruses and 4000 times smaller than bacteria. Domestic water filters with reverse osmosis
membranes harness the principle of body's metabolism on a cellular level. Only molecules of
certain size can penetrate cellular membrane.
Reverse osmosis system is a five-stage filtration unit functioning as follows (see section 2.4 for
reference numbers). Filter rack is connected to cold water supply with feed water adapter 4 and
feed valve 5. Red tube carries water from feed valve to the (rightmost) bulb filter rack. Incoming
water then passes through pre-filter cartridges 9. Pre-filter cartridges are designed to remove
solids (such as rust, sand, silt, etc), residual chlorine and organochlorines from water. After under-
going pre-treatment steps in the pre-filters, water enters into the fourth (and the most important)
stage: reverse osmosis membrane 11 contained in a special housing. Inlet of membrane housing is
connected with the third (leftmost) bulb filter rack through the feed side of auto shut-off valve
(four-way valve fastened to the top of filter rack). One of the two outlets supplies purified wa-
ter (permeate), and the other carries away water with rejected impurities (concentrate). The
membrane purifies water at the molecular level by passing through its pores only the water
molecules and the molecules of dissolved oxygen.
Tap water under
pressure
Figure 1
28
Molecules of smaller
size, pure water
Larger molecules
Code P0090636 - Rev 0 - 19/06/2019
Concentrate
for disposal
Membrane
Water
molecules