DESC:FIELD OF THE INVENTION
[001] The invention relates to water purification and more particularly to distillation of water using solar energy.
BACKGROUND OF THE INVENTION
[002] An adequate supply of drinking water is a prerequisite for a healthy life. Along with adequate supply, drinking water should not be contaminated since consumption of contaminated water for drinking or for preparing food can lead to diseases
[003] Drinking water comes from different sources, such as lakes, rivers, streams, springs and boreholes. Water from these sources is saline, hard, and has a high content of total dissolved salts, bacteria, viruses, parasites, heavy metals, etc. Hence water from these sources has to be treated before consumption.
[004] Various water purifying techniques such as water filters, water distillers have been developed to make water safe for consumption. However, in rural areas treatment of contaminated water is still a challenge since available water purifiers are dependent on external energy sources like electrical source, batteries, heating elements, etc. Also the available water purifiers are complex, expensive and need regular maintenance. Because of these reasons these water purifiers have not been employed in widespread use, especially in rural areas. Even-though package distilled water is now available in rural areas, consumption of packaged distilled water is not affordable for people in rural areas.
[005] In view of the above, there is a need in the art for a water purifier addressing at-least the above mentioned problems.

SUMMARY OF THE INVENTION
[006] Accordingly, the present invention in one aspect provides a solar water distillation apparatus comprising a housing, a main inlet line for introducing impure water in the apparatus from a water source, and a top chamber connected to the main inlet line for receiving impure water, at-least one distillation chamber stacked below the top chamber, the distillation chamber comprising an inlet for feeding impure water to the chamber, a tray for holding impure water, a collecting means provided adjacent to the tray for collecting distilled water; and an inclined surface provided above the tray extending from tray to collecting means, the water in the chamber evaporates and condenses on the inclined surface of the chamber forming water droplets which trickle down the inclined surface and falls in the collecting means.
[007] According to an embodiment of the invention, top chamber can be a distillation chamber or a storage chamber.
[008] In one another aspect, the present invention provides a system for solar water purification, the system comprising a solar water heater for heating water, a solar distiller connected to the solar water collector for receiving the heated water, the solar distiller comprising a top chamber, a plurality of distillation chambers stacked below the top chamber, each distillation chamber comprising an inlet for feeding water to the chamber, a tray for holding impure water, a collecting means provided adjacent to the tray for collecting distilled water, and an inclined surface provided above the tray extending from tray to collecting means, the water in the chamber evaporates and condenses on the inclined surface of the chamber forming water droplets which trickle down the inclined surface and falls in the collecting means, and a water filter.

BRIEF DESCRIPTION OF DRAWINGS
[009] Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 shows a solar water distillation apparatus in accordance with an embodiment of the invention.
Figure 2 shows a distillation chamber of the solar water distillation apparatus in accordance with an embodiment of the invention.
Figure 3 shows a solar water purifying system in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[010] The present invention provides a solar water distillation apparatus which is easily adaptable at any location exposed to solar energy. The water distillation apparatus provides high grade distilled water which can be utilized as a source of clean, hygienic and safe drinking water, especially in areas where water is contaminated.
[011] Figure 1 shows a solar water distillation apparatus 100 in accordance with an embodiment of the invention. The solar water distillation apparatus 100 comprises a housing 110, a main inlet line 120, a top chamber 130 and at-least one distillation chamber 140 stacked below the top chamber inside the housing 110.
[012] The main inlet line 120 is connected to at-least one of the chambers for introducing impure water or water to be distilled by the apparatus from a water source. According to the present invention, the main inlet line 120 is connected to the top chamber 130. In an embodiment, the top chamber 130 is a distillation chamber or a storage chamber.
[013] Figure 2 shows the distillation chamber of the present invention in detail. Each distillation chamber 140 comprises an inlet 142, a tray 144, a collecting means 146, and an inclined surface 148.
[014] The inlet 142 is provided on each distillation chamber. The inlet 142 feeds heated water into the distillation chamber. According to the present invention, the inlet 142 is a thermally insulated pipe which ensures that heated water is delivered to each distillation chamber. Further, inlet 142 comprises a valve for controlling the level of water introduced in each chamber.
[015] The tray 144 as shown in the figure is provided on a bottom surface of the distillation chamber. The tray 144 extends from a first end 144a to a second end 144b and holds the hot water which is introduced in the chamber via the inlet 142. In an embodiment of the invention, the tray 144 further accommodates a tube, preferably a copper tube. The tube is configured to be connected to the inlet 142 such that the hot water flows through the tube and into the tray 144. The tube extends in a zig-zag manner through the tray 144 and remains in contact with water filled in the tray 144. Since hot water passes through the tube, the tube will transfer heat to water in the tray 144, thereby maintaining a uniform temperature in the tray 144. Further, the tray 144 has a provision for excess water to escape so that the water in the tray 144 does not mix with the water in the collecting means 146. According to the present invention, the tray 144 can hold water in the range of 2 to 5 liters. However, the capacity can be increased or decreased depending upon size of the distillation apparatus.
[016] As shown in the figures, the collecting means 146 is provided adjacent to the tray 144, preferably near the second end 144b of the tray 144 for collecting distilled water. Alternately, the collecting means may be provided in the tray 144 by forming a partition near the second end 144b of the tray 144. The collecting means 146 is a U-shaped or V-shaped channel which extends through the length of the inclined surface 148. Also, the collecting means 146 has a height greater than the tray 144, thereby preventing the distilled water from being mixed with the water in the tray 144. Further, the collecting means 146 comprises an outlet 150 for guiding the collected water out of the distillation chamber. According to the present invention, the outlet 150 has a short length such that water falls drop-wise out of the chamber.
[017] The inclined surface 148 is provided above the tray 144 and the collecting means 146. The inclined surface 148 extends at an inclined angle with respect to the second end 144b of the tray 144, wherein the angle of inclination is between 20° to 30°. The hot water in the tray 144 evaporates and condenses on the inclined surface 148 forming water droplets which trickle down the inclined surface 148 towards the second end 144b where the collecting means 146 is provided.
[018] According to the present invention, the inclined surface 148 and the tray 144 are preferably made of a transparent material such as aluminum borosilicate glass. The inclined surface is preferably with a smooth surface and thick enough to get cooled very fast.
[019] Referring now to figure 1, which shows the distillation apparatus 100 comprising of a top chamber 130 and a plurality of distillation chambers 140A, 140B, 140C, and 140D stacked one below the other. As discussed above, the top chamber 130 can be a distillation chamber or a storage chamber. By way of an example, figure 1 shows top chamber 130 as a storage chamber. The top chamber 130 of the distillation apparatus 100 receives heated water through the main inlet line 120 from an external source such as a solar heater. In addition to the heated water, the top chamber 130 is also exposed directly to solar radiation which heats the top chamber 130 and the heated water received in the top chamber 130. Thus the hot water which is received in the chamber though it spreads along area of the chamber, heat from the water is not lost to the surroundings. The heated water is then fed to the subsequent distillation chambers that are stacked below the top chamber 130. In this regard, the distillation apparatus comprises a supply line 160. The supply line connects 160 the top chamber 130 to subsequent distillation chambers through the inlet 142 of each distillation chamber for feeding hot water to each distillation chamber overflowing from the top chamber 130, wherein water introduced in each chamber is controlled, and accordingly level in each distillation chamber is maintained at a pre-determined level. The heated water in each distillation chamber condenses on to the inclined surface 148 and trickles down the inclined surface 148 under gravity to the collecting means 146 of each distillation chamber. The distilled water is then guided through the outlet of the collecting means 146 to the collecting means 146 of the next distillation chamber and/or out of the apparatus. In this regard, the inclined surface 148 of the distillation chamber has a cut or opening for allowing water droplets from the outlet of previous collecting means 146 to pass through and fall into the collecting means 146 of the subsequent distillation chamber. Alternately, the outlet of each distillation chamber can be connected to a common outlet line for guiding the distilled water out of the apparatus. The distilled water can then be accumulated in a storage means or fed to a water filter for further purification. According to the present invention, the water remaining in the chambers can be drained out and re-used.
[020] The distillation apparatus shown in figure 1 further comprises of thermally insulated layer such as glass-wool surrounding the housing. Advantageously, the layer prevents any heat loss from the heated water and improves heat retention of each chamber.
[021] In an embodiment of the invention, the apparatus for solar water distillation is installed at a height from the ground via a suitable means such as a frame, stand, etc. Installing the apparatus above the ground enables the apparatus to get heated up due to radiative heating.
[022] Figure 3 shows a system for solar water purification in accordance with an embodiment of the invention. The system for solar water purification 300 comprises a solar water heater 310, a solar distiller 100 (shown in figure 1) and a water filter 320.
[023] The solar water heater 310 heats impure or saline water. The heated water is then fed to the solar distiller 100, where this impure heated water is distilled The distilled water is further processed by the water filter 320 to provide potable water, wherein small sized molecules of dissolved salts are removed, reducing the hardness of water as well as TDS values of water thereby improving overall taste of the water processed by the system.
[024] In an embodiment of the invention, the water filter, and solar water heater can be integrated with the solar distiller or can be stand-alone units.
[025] Advantageously, the present invention provides a water purifier which utilizes solar energy and is not dependent on any external sources of energy for purification of water, and hence is easily adaptable to any location exposed to solar energy.
,CLAIMS:We Claim :
1. A solar water distillation apparatus comprising:
a housing;
a main inlet line for introducing impure water in the apparatus from a water source; and
a top chamber connected to the main inlet line for receiving impure water;
at-least one distillation chamber stacked below the top chamber, the distillation chamber comprising:
an inlet for feeding impure water to the chamber;
a tray for holding impure water;
a collecting means provided adjacent to the tray for collecting distilled water; and
an inclined surface provided above the tray extending from tray to collecting means, the water in the chamber evaporates and condenses on the inclined surface of the chamber forming water droplets which trickle down the inclined surface and falls in the collecting means.

2. The solar distillation apparatus as claimed in claim 1 or 2, wherein the top chamber is a distillation chamber or a storage chamber.
3. The solar distillation apparatus as claimed in claim 1, further comprises a supply line, the supply line connects the top chamber to the subsequent distillation chambers through the inlet of each distillation chamber for feeding hot water to each distillation chamber overflowing from the top chamber.
4. The solar distillation apparatus as claimed in claim 1, wherein the distillation apparatus is thermally insulated.
5. The solar distillation apparatus as claimed in claim 1 further comprises a tube provided within the tray, the tube configured to be connected to the inlet such that the hot water flows through the tube and into the tray.
6. The solar distillation apparatus as claimed in claim 5, wherein the tube is preferably a copper tube.
7. The solar distillation apparatus as claimed in claim 1, wherein the collecting means comprises an outlet, the outlet provided for guiding the collected water to another collecting means and/or out of the apparatus.
8. The solar distillation apparatus as claimed in claim 1, wherein the inclined surface and tray of the chamber are preferably made of transparent material such as glass.
9. The solar distillation apparatus as claimed in claim 1 further comprises a common outlet line, wherein the outlet of each distillation chamber is connected to the common outlet line for guiding the distilled water out of the apparatus.
10. A system for solar water purification, the system comprising:
a solar water heater for heating water;
a solar distiller connected to the solar water collector for receiving the heated water, the solar distiller comprising a top chamber, a plurality of distillation chambers stacked below the top chamber, each distillation chamber comprising:
an inlet for feeding water to the chamber;
a tray for holding impure water;
a collecting means provided adjacent to the tray for collecting distilled water; and


an inclined surface provided above the tray extending from tray to collecting means, the water in the chamber evaporates and condenses on the inclined surface of the chamber forming water droplets which trickle down the inclined surface and falls in the collecting means; and
a water filter.