DESC:FIELD OF INVENTION
The invention relates to the field of water purification system, in particular drinking water. Since water may contain suspended solids, dissolved solids and microorganisms; it can be purified by physical and chemical treatment processes. Currently in the market place, the focus for the purification equipments is on RO membrane filtration and UV treatment.

BACKGROUND OF INVENTION
There are many water purification systems known in the prior art, all of which suffer from some or other disadvantages. One of the specifications of the drinking water is to have a maximum tds (total dissolved solids) content of 500 ppm. Some of the purifiers known in the prior art (e.g. those based on sediment filtration, ultra filtration and/or UV radiation) can remove the microbiological contaminations from drinking water but cannot lower the tds content. Some of the other water purifiers in the market perform efficient purification for removal of microorganisms, but need manual intervention by the consumer to maintain desirable tds level. In the prior art, on the basis of identified tds value of water by TDS controller, the user has the option to manually operate screw, switch, etc. in some of the models. In others, the tds selection is provided on the basis of selected bands. According to the input tds value, plurality of bands were made optional and in such designs, cut off for each band was based on input tds values. The action in such band system was essentially and entirely based on input tds values. Hence there was always a need for user intervention, which has been looked into as one of the sufferings of the prior art.

Reverse osmosis (RO) is a water purification technique in which almost 90% of the mineral values are removed from the water together with the microbiological contaminations. RO also results in significant wastage of water. Typically 3 litres of water are wasted in the ‘reject’ stream to produce 1 litre of ‘permeate’ (product) water. There is no way to control the mineral content in a RO driven process. Furthermore, the membranes being expensive, use of RO is a costly operation.

OBJECT OF THE INVENTION
The first object of the invention is to ensure that the water flow into the RO unit is restricted and to be put to use only when essential. Otherwise the inexpensive and efficient ultra filtration process is put into operation for purification. This results in significant savings of water besides being able to maintain the tds of the output water at a pre-determined value.

One of the other objects of the invention is to create a novel system and a method of water purification, to prepare drinking water from surface water sources which generally have low tds (total dissolved solids).

It is another object of the invention to create a novel system and a method of water purification, to prepare drinking water from ground water sources which generally have high tds (total dissolved solids).

It is another object of the invention to create a novel system and a method of water purification, to prepare drinking water from surface water sources which have low tds and also from ground water sources which have high tds. The system works on water sources irrespective of the tds value.

It is another object of the invention to create a novel system and a method of water purification to prepare drinking water, which prepared water has a tds of desired value or that value preferably does not exceed 500ppm.

It is another object of the invention to create a novel system and a method of water purification to prepare drinking water, from a ground water source which may have tds value at around 2000 ppm and which prepared water shall have a desired tds value but that value preferably not exceeding 500 ppm.

The other object of the invention is to create a novel system and a method of water purification, and which system and process do not extremely demineralise the source water.

The other object of the invention is to create a novel system and a method of water purification, and which system and process eliminate intentional need for using ‘mineralisation’ means and mineralisation step correspondingly.

The other object of the invention is to create a novel system and method of water purification, which specifically identifies the ‘mineral’ content of the water when the input water tds is below the threshold value of 200 ppm or so, and accordingly selects a purification method so as to not lower the tds value below the input value. This ensures the retention of the ‘natural’ mineral content of the water especially when the source is surface water.

The other object of the invention is to create a novel system and method of water purification, which specifically gives the option of selective operation of means and steps on the basis of desired tds value of the output water.

DESCRIPTION OF INVENTION
Clean and potable water is a necessity for domestic use. Boiling is the traditional method which has been used for centuries to purify water from microbiological contaminations. For the purification of water, the other conventional technologies are a combination of all or some of the following filtration units: pre-filter, sediment filter, activated carbon filter, UF (ultra filtration), RO (reverse osmosis) and finally UV (ultra violet) radiation. Some other purification systems are based on chemical treatment e.g. chlorination or adsorption through silver nano particles in a rice husk ash/activated carbon matrix.

As is known in the prior art, different types of water treatment technologies exist. UF removes tiny particles including microbiological contaminations from the water, RO removes dissolved salts, microbiological impurities and chemicals from the water; and UV removes living microorganisms by killing them using short wave length UV radiation.

In the present invention, the source may be surface or ground water. It is the objective of this work to study the device/system and ensure that the method works effectively regardless of the input tds content. The drinking water obtained from surface sources generally has low tds content. However, ground water, which is the source of drinking water in some other areas, may contain high tds. As per drinking water standards worldwide, a maximum of 500ppm tds in drinking water is allowed.

But the groundwater may contain as much as 2000 ppm tds or even more at certain geographical locations. Large concentration of tds results in low palatability and undesirable deposits of solids on the containers, pipelines etc. As mentioned, RO is a purification process which removes nearly 90-95% of the tds values from water. RO purifiers typically result in significant wastage of water. Furthermore, it removes even the healthy natural minerals making the water “mineral deficient”. This has prompted several purifier manufacturers to incorporate the so called “mineralization” step in the purification cycle by externally adding minerals through a cartridge. Much of these procedures are ad hoc in nature, since no precise information is available as to what minerals are removed by RO and how much are replenished by the “mineralization” step.

Water sourced from surface sources like rivers, lakes, ponds, canals etc. typically have tds content less than 200ppm; in some cases even the ground water may have similarly low tds values. As per the invention, it is opined that it is best not to disturb the natural mineral balance of the water if it is below a certain threshold value e.g. 200 ppm. Contrary to what is normally practiced in a RO purifier, the invention discloses a purification system and method which ensure that the RO is operational only when it is essential, otherwise an inexpensive and power-free Ultra filtration (UF) system is put into operation for the purification. The advantage of using UF is that the mineral balance of the input and output water is maintained. In this purification system and method, the user has the option of choosing the tds value of the output water.

In the case when the input tds is higher than the preset value, the innovative technology will maintain the output tds at a pre-determined level by controlling the water flow through UF with a feedback control system.

The innovative part of the proposed technology is the use of an Intelligent TDS Sensor (ITS). As such ‘normal’ TDS sensors are commercially available and are routinely used to measure the tds value of the input water. In this invention, there is an innovative attempt to integrate the commercially available tds sensor with our system and use it ‘intelligently’ to direct the flow of water either to (i) the UF or (ii) the RO or (iii) both UF and RO at a pre-determined ratio. The logic behind this is the following: if the TDS value of the input water is less than the preset value (e.g. less than 500 ppm), then there is no need for the use of RO (huge savings in terms of water recovery, power consumption, mineral balance and RO membrane life) and the entire water stream will be treated by UF alone. However, if the input water quality is inferior (say, TDS > 500 – 2000 ppm), then the ITS will manipulate the flow of water in both the streams (UF and RO) in such a way that an overall acceptable and preset TDS value is maintained in the output water.

In one aspect the invention discloses a purification system. It comprises of a source water inlet means (A) for connection to a supply of water. A potable water storage means (B). A prepared water outlet means (C) connected with the potable water storage means. A RO flush water outlet port means (D). A purified potable water outlet means (E) connected with the output end of potable water storage means for supplying potable water flow out from the storage means. A first filtration means (F1), which is an ultrafiltration (UF) means with its input end connected to the source water inlet means and output end connected to the prepared water outlet means. A second filtration means (F2) which is a reverse osmosis filtration (RO) means with an input end connected to the source water inlet means and permeate water passing through the RO membrane through a permeate water output port connected to the prepared water outlet means, the said RO means arranged parallel to UF means. A first TDS sensor means (T1) arranged proximate to the source water inlet means for detecting TDS of source water flowing out of the inlet means. A second TDS sensor means (T2) arranged proximate to prepared water outlet means for detecting TDS of prepared water flowing out of the prepared water outlet means into the potable water storage reservoir means. A processor means having a plurality of processing circuits operationally associated with the first TDS sensor means (T1) and the second TDS sensor means (T2) and arranged proximate to the output end of the UF filtration means for manipulating the detected TDS of the source water, detected TDS of UF treated source water and detected TDS of prepared water flowing out from the prepared water outlet means. A feedback means of a need valve coupled with a DC motor (M) operatively associated with the processor means to form an intelligent TDS sensor to control the flow through the UF line to maintain desired material content in the prepared water flowing out from the prepared water outlet means. A first solenoid means (S1) arranged between source water inlet means and UF means to allow regulated source water flow into the UF means and is operationally coupled to the processor means. A second solenoid means (S2) arranged between source water inlet means and RO means to allow regulated source water flow into the RO means and is operationally coupled to the processor means. A third solenoid means (S3) operationally coupled to the processor means and also the RO means to regulate flow of the reject water not passing through the RO membrane through a reject water outlet port of the RO means.

In another aspect, the ITS system which is basically the processor means in combination with the feedback means operationally actuating only the first solenoid means thereby regulating source water flow only to UF means if the source water TDS value is lower than a preset value.

In another aspect, the ITS system through the associated processor means in combination with the feedback means operationally is adapted to actuate the first solenoid means and/or second solenoid means thereby regulating source water flow to UF means and/or RO means, combinedly and selectively on the basis of detected TDS value of the source water, the UF treated water and the prepared water. This is the most inventive part of the ITS system wherein the flow of water and the manner of cleansing is optimised.

In another aspect, the purification system may include a pre-filter means (P1) disposed between the source water inlet means and the first and second filtration means, for removing suspended solids and floating particles from the source water.
In another aspect, the water purification system may include a sediment filter means (P2) disposed between the source water inlet means and first and second filtration means for removing fine suspended particles from the source water.

In another aspect, the water purification system may include an activated carbon filter impregnated with nano silver particles means (P3) disposed between the source water inlet means and first and second filter means for adsorbing organic compound and chlorine from the source water; and also for killing microorganisms by silver’s inherent antimicrobial properties.

In another aspect, the above mentioned pre-treatment means of the source water which typically are said pre-filter means, sediment filter means and nano silver impregnated carbon filter means all arranged sequentially. This is preferred for the purpose of removing the unwanted contaminations and ensuring that better water enters the treatment means which is the subject matter of this application.

In another aspect, the arrangement can include further an ultraviolet (UV) light source means for purifying further the prepared water flowing out of the prepared water outlet means, the said UV source means disposed between the prepared water out means and the potable means storage means.

In another aspect, the water purification system may include a potable water storage tank means includes a water level sensor (L) for detecting level of water and a tank drain solenoid 4 (S4), to drain the unused water stored in the storage tank.

In another aspect, the above potable water storage tank means comprises at least a water dispensing means (W) to dispense potable water.

In another aspect, the water purification system further includes a motor driven needle valve having a body configured with a predefined guide flow restricting path for diverting source to RO means and providing a predefined amount of flow restriction.

In another aspect, the water purification system further includes a pump means operable to pump source water into the RO means and also to boost source water pressure into the RO system.

A schematic of the proposed flow chart is given in Figure 1 (flow diagram).

PART PART NAME
A Water inlet means
B Potable water storage means – storage tank
C Water outlet means
D RO flush water outlet port means
E Purified potable water outlet means
F1 First filtration means (UF)
F2 Second filtration means (RO)
RO Reverse osmosis filtration
T1 First TDS sensor means – Input TDS Probe
T2 Second TDS sensor means – Output TDS Probe
S1 First solenoid means (if TDS < Set point)
S2 Second solenoid means (if TDS > Set point)
S3 Third solenoid means (Auto Flush)
S4 Tank drain solenoid 4
P Pump
UV UV Lamp
RW Reject water
L1 LPS
L2 PRV
FR Flow Restrictor
PI Pre-filter means
P2 Sediment filter means
P3 Nano silver particles means
L Water level sensor
M Motor
W Water dispensing means
DV Diverter Valve

Figure 1 illustrates the first embodiment of the invention where raw water passes through a pre-filter to remove suspended solid particles; then it passes through a sediment filter to remove finer particles; thereafter it goes through silver impregnated activated carbon filter which adsorbs organic compounds and chlorine from the water. Silver due to its antimicrobial property kills microbes present in the water. The water then passes through the ITS system, which senses the total dissolved solids content of the input water and if it is less than the preset value (say 100ppm, 500 ppm or any other intermediate value) then it passes through a hollow fiber UF membrane of 0.01 micron pore size to remove bacteria and viruses to provide microbiologically safe water. Under this condition, the power driven RO is not utilized and there is no water wastage (RO results in enormous reject water due to its pressure driven technology).

If the input tds is higher than the set point, then water in the ITS system passes through both the RO and UF simultaneously and depending on the set point; a needle valve will automatically adjust (based on provided logic) to maintain a flow rate such that the desired set point is achieved. The output tds sensor ensures that the system is always delivering purified water with fixed tds value with the help of a feedback control. In this scenario, water purification rate is higher compared to when only RO is used. Therefore under the given condition, the use of RO is for a lesser period for a desired quantity of purified water.

On the basis of output water tds, the ITS will correspondingly determine the UF flow rate to match the preset value, by using a proportional flow control valve to regulate the water flow until it matches the preset TDS value. The invention focuses not only on the selection of UF/RO where the technologies are capable of operation on their own, but also in particular where they are used in combination intelligently for the purification of drinking water. The invention has been accomplished by selectively using the combination of UF/RO in the system for water filter on the basis of measured input water and output water qualities, thereby bringing forth an innovative technology unknown in the prior art.

The purification system comprising of the units mentioned as above, also employs an UV lamp to ensure complete removal of microbiological impurities. Figure 2 is the block diagram of the proposed system.

Parts/Components of Figure 2 – Block diagram of the proposed filtration system.
Part no. Part names
1 Low pressure switch
2 Pressure reducing valve
3 Sediment filter
4 Silver impregnated carbon filter
5 Input TDS probe
6 RO booster pump
7 Ultra filtration unit
8 RO unit
9 Motorized ITS needle valve
10 Post Carbon filter
11 Output TDS probe
12 UV chamber
13 Storage tank

The method disclosed herein is an invention that is able to purify water by eliminating solid and liquid contaminants and also microbiological contaminants with selective and nominal usage of filtering elements. It is very simple but efficient and unique. The device is easy to design, calibrate and produce.

The device and method is scalable to large and small water treatment devices (illustrated in Figure 3) which includes experimental setup in left hand side and ITS setup in right hand side.

Parts/Components of Figure 3 – Actual photograph of a test set-up with ITS system and PLC
Part no.
Part names
1 Pre-filter
2 Sediment filter
3 Carbon filter
4 Pump
5 RO unit
6 UF
7 ITS Set-up
8 UV
9 PLC
10 Storage tank
11 Needle Valve
12 Motor

I. Examples : Experiment Series 1 with 100 gpd RO pump (Table 1)

Table 1 is illustrated in the tabular form under the drawings as figure 6.

In this Series, four experiments have been performed with and without ITS. The RO unit was run with a 100 gpd pump. The details of each are given below:

Example 1
Test setup is made as per the flow diagram given in Figure 1with the input water parameters fixed at 7psi pressure, 30?C and 422 ppm tds. The setup is run initially without ITS. The experiment is conducted to collect 50 liter permeate water together with the reject water, collected and measured simultaneously. Thereafter, the experiment is conducted with ITS “ON” at tds set point of 200 ppm.

From the experiment it was found that output tds(of purified water) display in PLC is always maintained at ~200 ppm, furthermore~ 31% of water saving has been achieved in rejected water compared to “only RO” condition.

Example 2
The experiment as mentioned in Example 1 was repeated at a different input pressure of 22 psi and tds level of 545 ppm. It is observed that water saving under these experimental conditions is 27.5%.

Example 3
Test setup is made as per the flow diagram depicted in Figure1. The input water parameters were maintained at 7psi pressure, 30?C and 845 ppm tds, initially the setup is run without ITS. Experiment is performed to collect 50 liter of permeate water. At the same time the reject water is also collected and measured. Then the experiment is repeated under the same conditions with ITS “ON” at a set point of 200 ppm tds.

From this experiment, it was found that the output tds display (of purified water) in PLC is always maintained at ~ 200 ppm and there is a savings of 9.6% of water in reject stream compared to only RO condition.

Example 4
The experiment as mentioned in Example 3, was performed at a different input pressure of 22 psi and tds of 946 ppm. The water savings in this case is 6.8%

The results are tabulated annexed (Table 1). Comparisons have been made when the setup was run with RO alone and with ITS technology.

Please note that for Experiment Series 1, the results are given in tabular form (Table 1).

II. Examples: Experiment Series 2 with 75 gpd RO Pump (Table 2)

Table 2 is illustrated in the tabular form under the drawings as figure 7.

For Experiment Series 2, the results are provided both in tabular (Table 2) and graphical forms (Figures 4 and 5). Figures 4 and 5 are drawn from the same results as tabulated in Table 2. The idea behind showing the results in graphical form is for the easy and clear understanding of the reader.

The experiments as depicted in Series 1 were repeated with a lower capacity (75 GPD) pump and somewhat different input water tds values. The results are presented in Table 2. It is a comparison of systems with ITS technology as per invention and that of “only RO”.

The results of Experiment Series 2 (using a 75 gpd pump) as provided in Table 2 are graphically presented in the following figures (Figure 4 & 5), wherein Fig.4 illustrates “water savings” and while Fig. 5 illustrates “power savings” for different input water qualities (expressed in terms of different tds values) when ITS technology is used in comparison to RO alone. These benefits are in addition to the optimized “mineral balance” of the input water. In the ITS technology, the output tds value was maintained within ~ 5% of the set point.

The invention has been described with examples, embodiments etc. for the purpose of understanding the invention. All the modifications and variations are well within the scope of invention. The applicant intends to rely on drawings submitted with provisional specification.
,CLAIMS:1. A water purification system comprising :
- a source water inlet means (A) for connection to a supply of water,
- a potable water storage means (B),
- a prepared water outlet means (C) connected with the potable water storage means,
- a RO flush water outlet port means (D),
- a purified potable water outlet means (E) connected with the output end of potable water storage means for supplying potable water flow out from the storage means,
- a first filtration means (F1), which is an ultrafiltration (UF) means with its input end connected to the source water inlet means and output end connected to the prepared water outlet means,
- a second filtration means (F2) which is a reverse osmosis filtration (RO) means with an input end connected to the source water inlet means and permeate water passing through the RO membrane through a permeate water output port connected to the prepared water outlet means, the said RO means arranged parallel to UF means,
- a first TDS sensor means (T1) arranged proximate to the source water inlet means for detecting TDS of source water flowing out of the inlet means,
- a second TDS sensor means (T2) arranged proximate to prepared water outlet means for detecting TDS of prepared water flowing out of the prepared water outlet means into the potable water storage reservoir means,
- a processor means having a plurality of processing circuits operationally associated with the first TDS sensor means (T1) and the second TDS sensor means (T2) and arranged proximate to the output end of the UF filtration means for manipulating the detected TDS of the source water, detected TDS of UF treated source water and detected TDS of prepared water flowing out from the prepared water outlet means,
- a feedback means comprising of a needle valve coupled with a DC motor (M) operatively associated with the processor means to form an intelligent TDS sensor to control the flow through the UF line to maintain desired mineral content in the prepared water flowing out from the prepared water outlet means,
- a first solenoid means (S1) arranged between source water inlet means and UF means to allow regulated source water flow into the UF means and is operationally coupled to the processor means,
- a second solenoid means (S2) arranged between source water inlet means and RO means to allow regulated source water flow into the RO means and is operationally coupled to the processor means,
- a third solenoid means (S3) operationally coupled to the processor means and also the RO means to regulate flow of the reject water not passing through the RO membrane through a reject water outlet port of the RO means.

2. The water purification system as claimed in claim 1, wherein the processor means in combination with the feedback means operationally actuates only the first solenoid means thereby regulating source water flow only to UF means if the source water TDS value is lower than a preset value.

3. The water purification system as claimed in claim 1, wherein the processor means in combination with the feedback means operationally is adapted to actuate the first solenoid means and/or second solenoid means thereby regulating source water flow to UF means and/or RO means, combinedly and selectively on the basis of detected TDS value of the source water, the UF treated water and the prepared water.

4. The water purification system as claimed in claim 1 comprising further a pre-filter means (P1) disposed between the source water inlet means and the first and second filtration means, for removing suspended solids and floating particles from the source water.

5. The water purification system as claimed in claim 1 comprising further a sediment filter means (P2) disposed between the source water inlet means and first and second filtration means for removing fine suspended particles from the source water.

6. The water purification system as claimed in claim 1 comprising further activated carbon filter impregnated with nano silver particles means (P3) disposed between the source water inlet means and first and second filter means for adsorbing organic compound and chlorine from the source water; and also for kills microorganisms by silver’s inherent antimicrobial properties

7. The water purification system as claimed in claim 4 to 6 comprising further the said pre-filter means of claim 4 sediment filter means of claim 5 and silver carbon filter means of claim 6 all arranged sequentially.

8. The water purification system as claimed in claim 1 comprising further an ultraviolet light source means for purifying further the prepared water flowing out of the prepared water outlet means, the said UV source means disposed between the prepared water out means and the potable means storage means.

9. The water purification system as claimed in claim 1, wherein the potable water storage tank means includes a water level sensor (L) for detecting level of water and a tank drain solenoid 4 (S4), to drain the unused water stored in the storage tank

10. The water purification system as claimed in claim 1, wherein the potable water storage tank means comprising further a water dispensing means (W) to dispense potable water.

11. The water purification system as claimed in claim 1 further includes a motor driven needle valve having a body configured with a predefined guide flow restricting path for diverting source to RO means and providing a predefined amount of flow restriction.

12. The water purification system as claimed in claim 1 further includes a pump means operable to pump (P) source water into the RO means and also to boost source water pressure into the RO means.