1. DESCRIPTION (Description shall start from next page.)
FIELD OF INVENTION
The present invention relates to a mineral cartridge for Reverse Osmosis (RO) based domestic water purifiers,
specifically to increase the mineral content and pH of RO permeate.
PRIOR ART
Water required for human consumption has to be free from contaminants like dirt, dust, organic and inorganic
impurities and harmful microorganisms like cysts, bacteria and viruses. Reverse osmosis is the most effective water
purification method. Typical Reverse Osmosis based system involves a Prefilter to remove large sized suspended
particles, a precarbon filter to absorb chlorine and odours. The water after passing through precarbon enters the
reverse osmosis membrane; whereby dissolved substances like salts, minerals, pesticides/ organic impurities are left
behind and pure water diffuses through the membrane. The concentrated dissolved substances and impurities are
removed through a flow restrictor; which maintains the pressure required by RO membrane to function. The purified
water coming out of RO membrane (RO permeate) may be stored in a tank or can be directly collected through a
faucet.
However, Reverse Osmosis membranes are not selective. They not only remove harmful contaminants present in
water, but also strip many of the good, healthy minerals from the water as well. These minerals serve vital functions
in the body's system, besides providing good taste to water. The water purified by RO membrane also has a lower pH
than the input raw water. Such water tends to be acidic and many people find its taste bitter.
To overcome these drawbacks and to achieve greater consumer acceptability, different methods are adopted. In some
systems, purified water from Reverse osmosis treatment system is fed through a mineral bed to replenish RO
permeate with desired minerals.
US Patent 5443739 describes water purification and dispensing apparatus, where a set ratio of minerals is injected
into purified water. The minerals are in solution form and are injected at a level so as to bring the level of total
dissolved solids in mineralised water upto 100 ppm. This type of apparatus is designed for use at retail outlets, where
customers fill their containers and pay for purified water.
Another US Patent 2008/0023400A1 describes a process, where a bypass flow branch is connected between water
inlet port and water outlet port in parallel with the ion separation module. The bypass flow branch has an orifice,
which restricts the flow of water and thereby determines how much of the total volume of water flowing through the
water treatment system travels through the bypass flow branch. By allowing a portion of the water to travel around
the ion separation module, some of the minerals in the source water remain in the treated water for health and taste
reasons. The size of the orifice in the bypass flow branch controls the amount of those minerals.
Another system described in Indian Patent No. 199716 comprises of: A reverse osmosis based drinking water purifier
having ability to control natural mineral content of raw water in purified water, comprising of: A reverse osmosis
membrane for subjecting water to reverse osmosis process to provide treated demineralized water and a control
valve to mix water containing natural mineral water with said treated demineralized water, and a further means of
filtration and/or treatment to purify the mixture and free it from bacteria and viruses to thereby provide for reverse
osmosis treated water having controlled natural minerals.
In such systems, 100% of raw water is not passed through RO membrane. A partial quantity of water is passed
through RO membrane; some quantity is by-passed through RO membrane and passed through other filtration media.
These filter media cannot remove heavy metals, pesticides, and some other inorganic/organic impurities. These
impurities have potential health hazards like cancer, delayed development of physical and mental faculties, kidney
damage, etc. Hence, water purification systems using this technology are not effective in providing 100% safe water.
Therefore, it is desirable to provide a water treatment system, where 100% water passes through RO membrane, yet
water is not acidic, has essential beneficial minerals and desirable taste.
OBJECTS OF THE INVENTION
According to the first objective of the present invention, there is to provide a mineral cartridge for Reverse Osmosis
(RO) based domestic water purifiers, which can improve the quality of RO permeate, by replenishing it with minerals
essential for human health.
Another objective of this invention is to provide a mineral cartridge for RO based domestic water purifiers, which can
change acidic RO permeate to alkaline.
Still another objective of the invention is to provide a mineral cartridge for RO based domestic water purifiers, which
can increase the TDS content of RO permeate and enhance its taste.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a mineral cartridge composition, by which water purified by Reverse
Osmosis based domestic water purifiers is replenished with certain essential minerals for human health ..
In another aspect, the invention provides a mineral cartridge composition, by which water purified by Reverse
Osmosis based domestic water purifiers is made alkaline.
In yet another aspect, the present invention increases the TDS content of water purified by Reverse Osmosis based
domestic water purifiers and enhances its taste.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a composition of a mineral cartridge to be used in Reverse Osmosis (RO) based domestic
water purifiers. RO based water purification systems generally consist of:
a) A prefilter, to filter out large sized suspended particles like dirt, dust, rust, sand, etc.
b) An activated carbon filter to absorb organic contaminants and chlorine
c) A reverse osmosis membrane to remove dissolved solids, heavy metals, pesticides or any other impurities
d) An optional UV lamp for deactivating any microbial organisms, not captured by RO membrane
e) An optional post carbon filter to trap odours and to enhance the taste of water.
Reverse osmosis systems are very efficient systems and can remove 90-95% of TDS present in feed water. Since RO
membrane does not selectively remove the harmful impurities, water treated with RO system is devoid of not only
the harmful impurities/ contaminants, but also of the essential beneficial minerals required for human health.
If TDS of feed water is low (500 ppm or less), TDS of RO permeate will be approx. 15-25 ppm. Consumers do not like
the taste of such low TD water. RO permeate is also acidic in nature, which is not good for health. Alkaline drinking
water is known to have certain health benefits, including antioxidant properties. Hence, it is imperative to convert
mineral deficient acidic RO permeate to mineral-rich alkaline water.
The present invention is a composition of an alkaline mineral cartridge, which can be placed after RO membrane in
the domestic water purifier. The output of alkaline mineral cartridge can be directly connected to the storage tank or
faucet or can be connected to a post carbon filter.
The composition of alkaline mineral cartridge may consists of one or more of the following constituents: Alkaline
ceramic balls, pH enhancing ceramic balls, silver impregnated activated carbon granules, mineralizing media for
replenishing essential minerals like calcium and magnesium, coral sand, etc.
These constituents may be put into a cartridge housing made of acrylonitrile-butadiene-styrene/polypropylene/low
density polyethylene. The caps of the housing may be sealed by spin welding.
The pH of output water of alkaline mineral cartridge may vary from 8-10. TDS of RO permeate increases by 300-500%
after passing through the said alkaline mineral cartridge, whereas mineral content increases by 500-600%.

Claims:
I claim:
1. A composition for alkaline mineral cartridge to be used in Reverse Osmosis based domestic water
purifiers.
2. A composition for an alkaline mineral cartridge, comprising of: one/more of the following: pH enhancing
ceramic balls, mineralizing media, activated carbon granules, coral sand
3. A composition for claim 1 comprising of mineralizing media for adding calcium and magnesium in Reverse
Osmosis permeate
4. A composition for claim 2 comprising of pH enhancing ceramic balls to increase pH of Reverse Osmosis
permeate
5. A composition for claim 2 comprising of taste enhancers for Reverse Osmosis permeate