Title of Invention

DISTILLATION DEVICE FOR THE DISTILLATION OF WATER BY SOLAR RADIATION

Abstract

The invention discloses a distillation device for the distillation of water, comprising: (a) a sheet which is substantially transparent to solar radiation, (b) a body which is positioned beneath the sheet and absorbs solar radiation, for the evaporation of water, and (c) collection means for the collection of distilled water, wherein the distillation device comprises inflation means for creating an air pressure beneath the transparent sheet, and stabilizing means for stabilizing the shape of the inflated transparent sheet, characterized in that the stabilizing means substantially extend over the entire surface of the transparent sheet, and that the stabilizing means are less stretchable than the transparent sheet.

Full Text

The invention relates to a portable distillation device for water in accordance with the preamble of claim 1. There is a known portable water distillation device which comprises a transparent top sheet and a body which absorbs solar radiation placed beneath it. The space beneath the sheet is sealed off in an airtight manner, so that it can be inflated using the mouthpiece, as a type of balloon. The surface area of the transparent sheet of the known distillation device is at most 1 to 2 m2. A quantity of water that is to be distilled, such as for example seawater or contaminated water, can be placed on the body which absorbs solar radiation. The solar radiation which impinges on the absorbent body through the transparent sheet will gradually evaporate the water that is to be distilled. This evaporated water will rise up and condense on the inside of the transparent sheet. On account of the curved shape of the inner side of the transparent sheet, the condensed water will run down along the inner side of this sheet until it is collected in water collection means. A distillation device for water of this type, using solar radiation for the distillation of water, is also known as a solar water still. One drawback of the known distillation device is that it can only yield a small quantity of distilled water, since the design of the distillation device is unsuitable for use in considerably larger dimensions. It is an object of the invention to create a distillation device for water which is relatively easy to move about and is suitable for a distillation device with a larger distillation capacity than the known distillation device. The object of the invention is achieved by a distillation device in accordance with the preamble of claim 1 which is characterized in that the distillation device comprises inflation means for creating an air pressure beneath the transparent sheet. The provision of inflation means makes it possible to apply a higher air pressure beneath the transparent sheet and/or for a greater volume of air to be moved under the transparent sheet, so that it is possible to create a distillation device of larger dimensions, with the pressure being sufficient to keep the shape of the inflated transparent sheet stable. This pressure needs to be higher in order to be able to support the weight of the transparent sheet and also to be able to withstand the influence of wind on the shape of the inflated transparent sheet. The retention of the shape of the inflated transparent sheet is particularly important for a water distillation device of the type described in the introduction, since this shape is used to discharge and collect the water which runs downwards along the inner side of the transparent sheet towards the water collection means. A sudden change in shape caused by the wind or a more gradual change in shape caused by wind or the weight of the transparent sheet itself may have a considerable influence on the production capacity of the water distillation device. The inflation means may, for example, comprise an air compressor or a fan. These inflation means are preferably driven by a motor, such as for example an electric motor. The energy to drive the motor can be generated, for example, by a solar panel. An additional advantage of providing inflation means is that there is no need for the space beneath the transparent sheet to be closed off in a completely airtight manner. Any pressure loss can be compensated for by using the inflation means to blow new air continuously or semi-continuously into the space beneath the transparent sheet. However, to counteract the escape of warm, humid air from the space as much as possible, it is generally desirable for the space to be kept as airtight as possible. Furthermore, it is advantageous for the distillation device to comprise stabilizing means which are able to stabilize the shape of the transparent sheet. These stabilizing means are used to ensure that the forces which are exerted on the transparent sheet by the pressure do not have to be absorbed completely, and preferably have to be absorbed as little as possible, by the transparent sheet. The stabilizing means are preferably less stretchable than the transparent sheet. This is because for cost reasons and to maximize the transparency of the transparent sheet, it is desirable to minimize the thickness of the transparent sheet. The thickness of the transparent sheet can now be kept small by providing stabilizing means, while at the same time it is possible to have a high level of certainty that the transparent sheet will be substantially dimensionally stable. The stabilizing means can highly advantageously be rolled and/or folded up. Stabilizing means of this type are easy to transport. Moreover, the distillation device is easy to erect, since the stabilizing means are easy to unroll or unfold. It is preferable for other components of the distillation device, in particular the transparent sheet, also to be designed such that they can be rolled and/or folded up. The stabilizing means may, for example, comprise nets or bands, such as tensioning bands, which extend over the surface of the transparent sheet. It is preferable for the stabilizing means to extend over a large part of the surface of the transparent sheet; more preferably, they are not attached to the transparent sheet. Placing the stabilizing means over a large part of the surface of the transparent sheet means that it is easy to obtain an optimum shape of the inflated sheet. Other preferred embodiments of the stabilizing means may for example comprise stabilizing means such as cables, nets or bands which are incorporated in the transparent sheet or are arranged beneath the transparent sheet. It is also possible for the stabilizing means to be formed by inflatable elements which are arranged on the transparent sheet. It is preferable for the stabilizing means to extend at least in one direction substantially over the length of the transparent sheet. Designing the stabilizing means in this way allows further stability of the distillation device to be obtained. It is advantageous for the stabilizing means to extend substantially over the entire surface of the transparent sheet. This results in a very stable shape of the inflated distillation device. The inflated distillation device may be of any suitable shape which will enable the distilled water to flow downwards along the inner side of the transparent sheet. In general, there will for this purpose be at least one sloping wall which in the inflated state preferably forms an angle of 10-50° with respect to the horizontal, more preferably 15-40O , most preferably 20-30°. The shape of the inflated distillation device may, for example, be the shape of a trapezium, a pyramid, a dome or the like. In one embodiment, the stabilizing means are designed as fibres which are arranged in or on the transparent sheet. The invention also relates to a method according to claim 16 and an assembly according to claim 17. Further advantages and characteristics of the distillation device according to the invention will be explained below with reference to an exemplary embodiment which is shown in the accompanying drawing, wherein: Figure 1 shows a cross section through the distillation device according to the invention, and Figure 2 shows a cross section through an alternative embodiment of a distillation device according to the invention. Figure 1 shows an embodiment of a distillation device according to the invention, denoted overall by reference numeral 1. The distillation device comprises a sheet 2 which is transparent to solar radiation and a groundsheet 3. The groundsheet 3 is provided, at least on the top side, with a material which absorbs solar radiation, for the purpose of absorbing solar radiation which passes through the transparent sheet 2 and impinges on the groundsheet 3. A quantity of water 4 that is to be distilled and is not suitable as drinking water, such as for example seawater, brackish water and contaminated water, has been placed on the groundsheet 3. A preferably closable opening (not shown) is arranged in the transparent sheet 2 or the groundsheet 3, allowing a quantity of water to be placed on the groundsheet and allowing residual water or slurry which remains behind after distillation to be removed. At the periphery, the transparent sheet 2 and the groundsheet 3 are joined to one another by means of a joining element '5, so as to form, as it were, a large, substantially airtight "bag". Between the transparent sheet 2 and the groundsheet 3 which are joined to one another is a pressure space 6 which can be filled with air in order to create a superatmospheric pressure, with the result that the transparent sheet can adopt a defined dome shape. There is a fan 7 which is driven by a motor 8 for blowing air into the pressure space. In the embodiment shown, this motor is an electric motor which is provided with energy by, for example, a solar panel 9 or a battery or generator or the like. As an alternative to the fan 7, it is also possible to provide inflation means of a different type, such as an air compressor or the like. A net 10 which extends substantially over the surface of the transparent sheet and is fixed to the ground at its edge is arranged over the transparent sheet 2. The material of which the net 10 is made is generally less stretenable than the material of the transparent sheet 2. It is preferable for the material of the net 10 to at least partially transmit solar radiation. As a result of air being blown into the pressure space 6, at a given moment a superatmospheric pressure will be produced in the pressure space, which will ensure that the transparent sheet 2 with the net 10 arranged over it will be inflated. In particular on account of the presence of the net which is attached to the ground all the way around, the transparent sheet 2 will adopt a specific desired shape. This is because the forces resulting from the pressure on the transparent sheet 2 will be absorbed by the net 10. By further increasing the pressure in the pressure space 6 by blowing in more air, it is possible to obtain a very stable shape, and relatively little stress has to be absorbed by the transparent sheet 2. Consequently, it is not necessary for the transparent sheet to be very strong/thick. This design makes it possible for the distillation device to be made considerably larger than the distillation devices for water based on solar radiation which have been disclosed hitherto. In another embodiment, it is possible to provide control means for controlling the pressure in the pressure space 6 beneath the transparent sheet 2. Control means of this type on the one hand, for example, are able to prevent the pressure in the pressure space from becoming too high, which can cause damage to the materials of the distillation device, and on the other hand can prevent the pressure in the pressure space being too low, which can cause the shape of the inflated transparent sheet to become unstable. If the distillation device 1 is erected as shown in Figure 1, solar radiation will pass through the transparent sheet 2 and impinge on the groundsheet 3. This groundsheet 3 will absorb the solar radiation and convert it into heat, with the result that the water 4 is heated. Water will evaporate and rise up. The evaporated water will at least partially condense on the inner side of the transparent sheet 2 and run downwards under the force of gravity. There, it will be collected by water collection means. In the embodiment shown, these water collection means are designed as a gutter 11 which is arranged on the transparent sheet, for example by sealing. The water can flow through this gutter 11 to one or more taps 12. The base surface area of a possible embodiment of the distillation device 1 is preferably at least 10 m2, and is preferably between 100 and 2000 m2. The yield of a distillation device of this type may vary from 3.5 to 6 litres of distillate per m2 of base area. In principle, it is possible to select any shape for the inflated transparent sheet, although it is a condition that it must be possible for the water condensed on the inner side of the transparent sheet to run towards the water collection means, preferably under the force of gravity. For design reasons, it has been found that a pyramid or half- doughnut shape (with an annular base surface) is very suitable. The transparent sheet 2 may, for example, be made from PVC, polyethylene (PE) or polypropylene (PP), preferably with a thickness of from 0.18 to 0.5 mm. The groundsheet may, for example, be made from a black sheet of PVC, polyethylene or polypropylene with a thickness of from 0.75 to 2 mm. In the inflated state, the superatmospheric pressure in the tent may be in the range from 50-200 Pascal. If a fan is used to inflate the transparent sheet, the fan power during inflation is, for example, of the order of 70-400 watts. Figure 2 shows a second possible embodiment of a water distillation device according to the invention, which is denoted overall by reference numeral 20. The water distillation device 20 comprises a transparent sheet 21 and a body 22 which absorbs solar radiation positioned beneath it. The body 22 which absorbs solar radiation is a body which floats on a pool 23 containing water that is to be distilled. This pool 23 may be made specially for this application but may also be an existing pool of water. The transparent sheet 21 may span the pool entirely or only partially. The material of the absorbent body 22 is such that it can hold the water to be distilled, the material preferably sucking up the water out of the pool of water 23. The material may, for example, be a black sponge-like material which is made to float by means of floats. It is also possible to provide means which hold the absorbent body 22 at least partially above the water level of the water to be distilled instead of a floating absorbent body 22 and/or to provide the absorbent body with dimensions which are such that it at least partially projects above the water level. Between the transparent sheet 21 and the pool of water 23 there is a pressure space 24 into which air can be blown by the inflation means in the form of a fan 25 in order to create a certain superatmospheric pressure in the pressure space 24. A net 26, which has the same function as described above in connection with the embodiment of Figure 1, is arranged on the transparent sheet 21. As a result of the creation of the superatmospheric pressure, the transparent sheet 21 with the net 26 placed over it will adopt a defined stable shape, with the result that the forces generated as a result of the superatmospheric pressure are absorbed in particular by the net 26 stretched over the transparent sheet 21. At its periphery, the transparent sheet 21 is placed against the ground in as airtight a manner as possible, in order to counteract the escape of air from the pressure space 24 as much as possible. For this purpose, the periphery of the transparent sheet 21 is provided with a somewhat heavier flap 27 which at least partially lies on the ground. It is equally possible for there to be a continuous or discontinuous air loss at the periphery of the transparent sheet 21 on account of the connection between the transparent sheet 21 and the ground not being completely airtight. However, this air loss can easily be compensated for by operating the fan 24 continuously or semi-continuously. It is in this way also possible to compensate for other air pressure losses as a result of air escaping from the pressure space 24. It may in this respect be attractive to provide control means for controlling the pressure in the pressure space 24 as already described above. Water collection means in the form of a gutter 28 are arranged on the inner side of the transparent sheet 21. This gutter 28 collects the water which has condensed on the inner side of the transparent sheet and has then flowed downwards along the inner side of the transparent sheet, in order to pass it to one or more taps 29 which provide the fresh water to the outside of the. transparent sheet 21. As an alternative to the net shown in Figures 1 and 2, it is also possible to provide other types of stabilizing means, such as (tensioning) bands, meshes of cords or cables, or stabilizing means which are joined to the transparent sheet, such as inflatable bands or stronger strips. However, it is preferable for the stabilizing means not to be attached to the transparent sheet, in order to minimize the risk of damage. In this case, attaching the stabilizing means to the transparent sheet entails additional production steps, making the transparent sheet more expensive. One advantage of the distillation device described above is that it can be erected quickly, in particular by carrying out the following steps: laying the transparent sheet, with any ground sheet attached to it, on the ground and/or on water, placing the net or other stabilizing means over it, attaching the net to the ground at the periphery or near the periphery and inflating the transparent sheet into the desired shape. It is also possible for the distillation device to be dismantled/taken down quickly by allowing the air which has been blown into the pressure space to flow out of it. As a result, the distillation device can quickly be taken down, for example in the event of a hurricane or storm or the like, in order to prevent damage to the distillation device. Then, after the storm or hurricane has passed, it is quick and easy to reinflate the transparent sheet, so that the production of fresh water can be continued with the minimum possible interruption. Another advantage of the two embodiments shown is that they are easily portable. After the distillation device has been used, the pressure space can be emptied. Then, the sheet or sheets can be rolled and/or folded up so as to produce a small package. A package of this type can easily be transported in a car or lorry together with the inflation means and if appropriate the absorbent body, which is preferably also designed such that it can be rolled and/or folded up. As an alternative to the embodiment of the stabilizing means described above in the form of nets or bands or the like which are stretched over the transparent sheet, it is also possible to use other stabilizing means. In general, the stabilizing means can preferably be rolled and/or folded up. The stabilizing means may be formed, for example, by fibres or other reinforcing elements which are arranged in or on the transparent sheet. In an advantageous embodiment, the transparent sheet with stabilizing means is formed by a fibre- reinforced sheet. All these alternative embodiments of the stabilizing means are deemed to be covered by the scope of protection of the invention. We claim: 1. Distillation device for the distillation of water, comprising: a sheet which is substantially transparent to solar radiation, a body which is positioned beneath the sheet and absorbs solar radiation, for the evaporation of water, and collection means for the collection of distilled water, wherein the distillation device comprises inflation means for creating an air pressure beneath the transparent sheet, and stabilizing means for stabilizing the shape of the inflated transparent sheet, characterized in that the stabilizing means substantially extend over the entire surface of the transparent sheet, and that the stabilizing means are less stretchable than the transparent sheet. 2. Distillation device as claimed in claim 1, wherein the stabilizing means can be rolled and/or folded up. 3. Distillation device as claimed in claim 1 or 2, wherein the stabilizing means extend over the surface of the transparent sheet but are not attached to it. 4. Distillation device as claimed in any one of claims 1- 3, wherein the stabilizing means comprise a net which is placed over the transparent sheet. 5. Distillation device as claimed in any one of the preceding claims, wherein the stabilizing means comprise one or more bands, in particular tensioning bands, which are placed over the transparent sheet. 6. Distillation device as claimed in any one of claims 1- 5, wherein the stabilizing means are placed beneath the transparent sheet. 7. Distillation device as claimed in any one of claims 1- 6, wherein the stabilizing means are incorporated in the transparent sheet. 8. Distillation device as claimed in any one of claims 1- 7, wherein the stabilizing means are formed by reinforcing elements, such as fibres, which are arranged in or on the transparent sheet. 9. Distillation device as claimed in any one of claims 1-8, wherein the distillation device comprises a groundsheet which at or near an edge is joined in an airtight manner to an edge of the transparent sheet. 10. Distillation device as claimed in any one of claims 1-9, wherein the groundsheet is the body which absorbs solar radiation. 11. Distillation device as claimed in any one of claims 1-10, wherein the body which absorbs solar radiation comprises a material which at least partially holds the water that is to be distilled. 12. Distillation device as claimed in any one of claims 1-11, wherein the inflation means comprise an air compressor. 13. Distillation device as claimed in any one of claims 1-12,wherein the inflation means comprise a fan. 14. Distillation device as claimed in any one of claims 1-13, wherein the water collection means comprise a gutter which is formed around the transparent sheet and/or the groundsheet. ABSTRACT DISTILLATION DEVICE FOR THE DISTILLATION OF WATER BY SOLAR RADIATION The invention discloses a distillation device for the distillation of water, comprising: (a) a sheet which is substantially transparent to solar radiation, (b) a body which is positioned beneath the sheet and absorbs solar radiation, for the evaporation of water, and (c) collection means for the collection of distilled water, wherein the distillation device comprises inflation means for creating an air pressure beneath the transparent sheet, and stabilizing means for stabilizing the shape of the inflated transparent sheet, characterized in that the stabilizing means substantially extend over the entire surface of the transparent sheet, and that the stabilizing means are less stretchable than the transparent sheet.

Documents:

02210-kolnp-2007-abstract.pdf

02210-kolnp-2007-assignment.pdf

02210-kolnp-2007-claims.pdf

02210-kolnp-2007-correspondence others 1.1.pdf

02210-kolnp-2007-correspondence others.pdf

02210-kolnp-2007-description complete.pdf

02210-kolnp-2007-drawings.pdf

02210-kolnp-2007-form 1.pdf

02210-kolnp-2007-form 3.pdf

02210-kolnp-2007-form 5.pdf

02210-kolnp-2007-gpa.pdf

02210-kolnp-2007-international search report.pdf

02210-kolnp-2007-priority document.pdf

2210-KOLNP-2007-(23-02-2012)-ABSTRACT.pdf

2210-KOLNP-2007-(23-02-2012)-AMANDED CLAIMS.pdf

2210-KOLNP-2007-(23-02-2012)-DESCRIPTION (COMPLETE).pdf

2210-KOLNP-2007-(23-02-2012)-DRAWINGS.pdf

2210-KOLNP-2007-(23-02-2012)-EXAMINATION REPORT REPLY RECEIVED.pdf

2210-KOLNP-2007-(23-02-2012)-FORM-1.pdf

2210-KOLNP-2007-(23-02-2012)-FORM-2.pdf

2210-KOLNP-2007-(23-02-2012)-FORM-3.pdf

2210-KOLNP-2007-(23-02-2012)-OTHERS.pdf

2210-KOLNP-2007-(23-02-2012)-POWER OF ATTORNEY.pdf

2210-KOLNP-2007-ASSIGNMENT.pdf

2210-KOLNP-2007-CORRESPONDENCE 1.1.pdf

2210-KOLNP-2007-CORRESPONDENCE.pdf

2210-KOLNP-2007-EXAMINATION REPORT.pdf

2210-KOLNP-2007-FORM 18.pdf

2210-KOLNP-2007-FORM 3.pdf

2210-KOLNP-2007-FORM 5.pdf

2210-KOLNP-2007-GPA.pdf

2210-KOLNP-2007-GRANTED-ABSTRACT.pdf

2210-KOLNP-2007-GRANTED-CLAIMS.pdf

2210-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

2210-KOLNP-2007-GRANTED-DRAWINGS.pdf

2210-KOLNP-2007-GRANTED-FORM 1.pdf

2210-KOLNP-2007-GRANTED-FORM 2.pdf

2210-KOLNP-2007-GRANTED-SPECIFICATION.pdf

2210-KOLNP-2007-OTHERS.pdf

2210-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf

abstract-02210-kolnp-2007.jpg