Petra Wadsdtrom -- Solvatten water purification system > [![](0logo.gif)](../index.htm) **[rexresearch.com](../index.htm)** > > > > --- > > > > **Petra WADSTROM** > > **Solvatten Water Purification** > > --- > > **SOLVATTEN AB** > **Breda gatan 3** > **11532 Stockholm** > **Sweden** > > **Tel: +46854352439** > **eMail: info@solvatten.se** > > --- > > > > ![](A3.jpg) > ... ![](solv3.jpg) > > ![](solvatten1.jpg) > > --- > > [**http://www.newscientist.com/blogs/shortsharpscience/2009/01/solar-power-might-become-big.html**](http://www.newscientist.com/blogs/shortsharpscience/2009/01/solar-power-might-become-big.html) > > **Solar Power for Cheap Cold Food and Pure > Water** > > **by** > > **Colin Barras** > > Solar power in the developed world is becoming ever more > high-tech, and big business. Witness the attempts to steer > president-elect Obama towards space-based solar power. > > But low-tech ways to harness the Sun's energy can have big > impacts too, as these two new simple solar gadgets for use in > poor areas of the world show: a solar-powered fridge and a > drinking water steriliser, without a single moving part > between them. > > The fridge, designed by Emily Cummins of West Yorkshire in > the UK, consists of a two-walled cylinder, with the outer one > perforated. Wet sand or soil fills the gap between the two > walls. When sunlight heats the out wall and wet material, > evaporating water cools the inner cylinder and its contents in > the same way evaporating sweat cools our bodies. Cummins > perfected her invention on a trip to Namibia. > > The Swedish invention Solvatten is also easy to use. Simply > pour several litres of water into its two tanks, leave it in > the sun for a few hours and collect the sanitised drinking > water. An indicator signals it is safe to drink once the > temperature inside has reached 55 degC. That heating, together > with exposure to UV radiation, helps destroy harmful bacteria, > and the water is also filtered during pouring to remove > particulates. > > It works even on cloudy days, the inventors say, although it > can take up to 6hrs to reach temperature. Unfortunately, it > doesn't work at all when it's raining. You can see Solvatten > in action in the video below, which reports on a trial of the > device in Nepal. > > --- > > [**http://www.solvatten.se/SOLVATTEN/Start.html**](http://www.solvatten.se/SOLVATTEN/Start.html) > > "SOLVATTEN makes unsafe water drinkable by using solar > energy. The portable 10 liter container is a patented and > scientifically approved Swedish invention. Put SOLVATTEN in a > sunny place, give it 3-4 hours and the water will be > drinkable! An indicator shows when it is safe to drink... > SOLVATTEN uses the idea of combining heat, UV and built-in > filter in a specially designed container to clean contaminated > water." > > "The number of days that SOLVATTEN can be used over the year > depends on several factors. Considering the geographical > location, prevailing weather conditions and climatic pattern > the estimated range is between 250 and 365 days in a year. If > the conditions are good, SOLVATTEN can be used twice a day... > If we assume that we could use SOLVATTEN twice a day during > sunny days, it will provide 20 liters of warm water. To boil > one liter of water you need 1 kg of firewood which would in > the end save about 20 kg wood/day assuming the weather is > fine... If SOLVATTEN is used once a day during 250 days in a > year, you can save 2 500 kg of firewood. That means less soil > erosion and saves a large amount of CO2." > > **Instructions :** > > **Animation : ** > > **Video :** > > **Photos : ** > > --- > > [**http://v3.espacenet.com/publicationDetails/biblio?KC=A&date=20071107&NR=101068578A&DB=EPODOC&locale=en\_EP&CC=CN&FT=D**](http://v3.espacenet.com/publicationDetails/biblio?KC=A&date=20071107&NR=101068578A&DB=EPODOC&locale=en_EP&CC=CN&FT=D) > > **US2007262010** > **Container for Purifying Water by > Utilization of Sunlight** > > 2007-11-07 > Inventor(s): PETRA WADSTROM [SE] > Classification: - international: A61L2/04; > A61L2/10; A61L2/26; C02F1/02; C02F1/30; C02F1/32; F24J2/34; > A61L2/04; A61L; A61L2/10; A61L2/26; C02F1/02; C02F1/30; > C02F1/32; F24J2/04- European: A61L2/26; C02F1/02; > C02F1/30; C02F1/32; F24J2/34B > > Also published as: WO2006059948 (A1) / > SE0402941 (A) // SE527988 (C2) // > EP1814602 (A1) // CN101068578 (A) > > **Abstract** -- The present invention relates to a > container (2) for purifying water by utilization of sunlight, > comprising a first surface (4, 8', 9', 10', 12') that is > formed of a permeable layer for sunlight and a second surface > (6, 8'', 9'', 10'', 12'') that is formed of an absorbing layer > for sunlight. Further, the container comprises a first opening > (14) and a second opening (16), respectively, provided with > filter elements (18, 19). Filling with water is intended to be > done in the first opening (14) and discharge of water is > intended to be done through the second opening (16) after the > water in the container (2) has been heated to a temperature of > at least 600C after exposure by sunlight and also exposure of > ultraviolet radiation in order to make it possible to kill > undesired micro-organisms. > > **BACKGROUND** > > [0002] Contaminated drinking water is frequent and a large > problem in many parts of the world, particularly in developing > countries. 1.1 billion people are without reliable drinking > water and 1.6 billion are lacking electricity. There is a > great demand for being able to purify drinking water in a > simple way. Following natural disasters, at war and other > large catastrophes such as Aids epidemics, which often leaves > children without their parents, the problems with purification > of water often culminates and causes usually serious diarrhoea > diseases. WHO has provided a standard that disinfecting > systems have to fulfil in order to be considered acceptable. > This standard requires that a system shall manage to treat > water with 100000 colon forming bacillus (colony forming > units--CFU) of E-coli per 100 ml water and from this produce > water less than one (1 part) CFU per 100 ml. > > [0003] It is previously known apparatuses and methods for > purifying drinking water from harmful parasites and > micro-organisms, which known apparatuses/methods utilises > UV-light and/or heating to a temperature above 60.degree. C. > during about 1 h for pasteurization of the water. Natural > sunlight contains UV-light and large amounts of heat energy. > It is also known, to use simple pieces of cloth to filter out > micro-organisms that usually are combined with larger > particles. In common with most of the known apparatuses is > that they comprises many and expensive components, are > relatively complicated and/or have not a suitable construction > that ensures a guaranteed purification of the water. > > [0004] Through EP-A1-1106188 is previously known a container > and a method for disinfection of drinking water. The container > is preferably shaped of a flexible plastic material, such as a > plastic bag. One side of the container comprises a > UV-transparent layer and a second side comprises a layer that > produces heat at exposure in sunlight. The container comprises > a sealable opening that is used for discharging and filling of > water. > > **DESCRIPTION OF THE INVENTION** > > [0005] One object with the present invention is to achieve a > container for purifying water that at least partially > eliminates those drawbacks that are associated with > apparatuses according to the state of the art. A further > object is that the purifying of water in the container > according to the present invention should fulfil WHO standard. > An additional object is to achieve a container that to high > degree ensures purifying of water in the container, that is > simple to use, easy to distribute and cheap to produce. > > [0006] This object is achieved with a container for purifying > of water by utilization of sunlight according to the present > invention as defined in claim 1, which comprises a first > surface that is formed of a permeable layer for sunlight and a > second surface that is formed of an absorbing layer for > sunlight. The second absorbing surface is composed of up to > about 2/3-parts of the delimiting surfaces of the container. > Further the container comprises a first sealable opening and a > second sealable opening, respectively. The respective opening > is provided with filter elements, whereby filling with water > is intended to be done in the first opening and discharge of > water is intended to be done through the second opening after > the water in the container has been heated to a temperature of > at least 60.degree. C. after exposure by sunlight and also > exposure of ultraviolet radiation in order to make it possible > to kill undesired micro-organisms. > > [0007] By those means, it is achieved that the one of the > sides of the container, which container is filled with water, > that is to be placed against the sunlight, is suitably shaped > of a completely transparent layer, in order to allow a maximum > of sunlight to pass to shine through the water, and the other > side of the container is of an absorbing material, a so called > absorber, which absorbing layer is hit by the sunlight. This > absorber may substantially be composed of a black surface. The > sunlight hits the absorber, whereby conversion to heat energy > takes place through emission. The water temperature increases > fast and the heat is kept in the container. The water is also > exposed for UV-radiation and kills undesired micro-organisms > and disinfects in that way the water. > > [0008] The two openings on the container that each are > provided with a respective filter element, implies that the > risk for contamination of the water in the container can be > minimised. Thanks to that one opening is intended for > discharge and one for filling of water, it can by those means > be achieved that purified water in the container is not > discharged through an opening for filling of water, which can > re-contaminate the water as a consequence of those > micro-organisms, which were separated at the filling, that can > be left on the filter elements. Owing to that the opening for > discharge of water also comprises a filter element, it is > achieved that the water in the container becomes sealed, and > thus means a safety that the water neither is contaminated > through introduction of micro-organisms, parasites and also > larger impurities through the discharge opening. One advantage > with the solution according to the present invention is that > the container can be formed with a shape, such as for instance > a relatively flat design, which is most preferably according > to an embodiment of the present invention in order to > facilitate that the UV-radiation meets as large radiation > surface as possible for disinfection of micro-organisms in the > water. A shallow/flat shaping makes it also easy to store, > transport, distribute, handle and can be shaped with a > attractive design. Yet an advantage is that the present > invention eliminates the need for chemical additives, > electricity and complicated techniques of containers for > purifying of water, at the same time as the purified water in > the container can fulfil the demands according to the WHO > standard. The container is refillable and can be produced to a > low cost. The container according to the invention also > creates the possibility for an easy distribution and > uncomplicated handling for the end user thanks to the ability > to stack them. > > [0009] The first surface that is formed of a layer for > transmitting the sunlight is suitably formed of a transparent, > see-through material such as a plastic that keeps its high > degree of transparency, in order to let through a maximum of > sunlight, during repeated use and thus not becomes turbid > after a short time of use. > > [0010] The whole container can be of the same material as the > above mentioned first surface, suitably of plastic material, > however where the second surface is formed of an absorbing > layer for sunlight, and suitably not a transparent layer. The > layer is suitably substantially black in its colour. Thus, the > second surface of the container can be painted black, produced > from black plastic material, can be provided with a black > layer, a film that is pasted on the side or in similar way > provided with a sunlight and UV-radiation absorbing layer. The > second absorbing surface comprises suitably at least about > half the delimiting surface of the container and up to about > 2/3-parts of the delimiting surfaces of the container, which > has been shown to provide a faster heating to a temperature of > at least 60.degree. C. after exposure by sunlight compared to > if only one fourth to one third of the container is of > absorbing material. The first sunlight pervious surface is > composed of suitably up to about half the delimiting surface > of the container. > > [0011] Coarser impurities are separated by deposition on the > filter when contaminated water is filled in the first opening. > At the discharge of water, the second opening is used since > impurities can be present on the filter of the first opening > for the filling. Also the second opening for discharge of > water is provided with a filter in order to avoid that > impurities are introduced in the container during discharge. > By using two sealable openings, vacuum in the container can be > avoided in such a way that a lid that seals the filling > opening can be slightly opened to let in air, such that the > purified water in the container can be poured out through the > discharge opening. The openings may also comprise filters for > purification of chemical substances. > > [0012] Further advantages and features according to > embodiments of the invention are evident from the claims, and > also in the following from the description of the embodiments. > > **DESCRIPTION OF THE DRAWINGS** > > [0013] The present invention will now be described more in > detail in embodiments, with reference to the attached > drawings, without limiting the interpretation of the invention > thereto, in which > > **FIG. 1A** in a perspective view schematically shows a > container in accordance with the present invention, and > > ![](fig1.jpg) > > **FIG. 1B** in an explanatory sketch shows sealable > openings of an upper part of the container in FIG. 1. > > ![](fig2.jpg) > > **DETAILED DESCRIPTION OF EMBODIMENTS** > > [0016] A container 2 for purifying water by utilization of > sunlight is shown in FIG. 1, in accordance with the present > invention. According to the embodiment in FIG. 1A-B, is a > container 2 illustrated that comprises six sides, a first side > 4, a second side 6 opposite the first side, two short sides > 8,9, a bottom side 10 and a top side 12. In this way is a > relatively shallow/flat container 2 formed that easily can be > placed on the ground. By having a flat shaping, it is intended > that the first and the second side 4, 6, respectively, have an > essentially larger extension than the other sides 8-10, 12. A > relatively flat form of the container also facilitates that > the UV-radiation meets a relatively large radiation surface, > i.e. a target area of the container, such that the water > effectively and time efficiently is exposed for the > UV-radiation and thereby facilitates at least some killing of > micro-organisms. Within the scope of the inventive concept, > the container may of course be of another shape, such as for > example comprising more sides than six or be essentially > cylindrical, although such a shape may imply that it is harder > to place in correct position on the ground. In that respect, > it is most preferred to have a relatively flat container, > having plane sides, in accordance with the present invention. > According to the present invention, the first sunlight > permeable surface in the embodiment shown in FIG. 1A-B > comprises the first surface 4, and also the halves 8', 9', > 10', 12' of the short sides 8, 9, the bottom side 10 and the > top side 12 that is adjacent to the first side 4. Further as > evident from FIGS. 1A-B, the second sunlight permeable surface > comprises the second side 6, and also the halves 8'', 9'', > 10'', 12'' of the short sides 8, 9, the bottom side 10 and the > top side 12 that is adjacent to the second side 6. In > accordance with the container 2 according to FIGS. 1A-B, the > short sides 8, 9, the bottom side 10 and the top side 12 are > in that respect half painted black adjacent the second side 6. > > [0017] Further, the container comprises a first sealable > opening 14 and a second sealable opening 16, respectively, > provided with a respective filter element 18, 19, whereby > filling with water is done in the first opening 14 and > discharge of water is done through the second opening 16 after > the water in the container 2 has been heated to a temperature > of at least 60.degree. C. after exposure by sunlight. The > filter elements 18, 19 can suitably be fixed in the openings > 14, 16, preferably fixed by welding, moulded or in similar way > securely arranged in the openings. The respective filter > element 18, 19, according to an embodiment of the present > invention, may be arranged in a cylindrical house-formed body > (not shown), provided with male threads, which is adapted to > be screwed in the respective opening 14, 16, provided with > corresponding female threads. The filter elements 18, 19 > according to the present invention are preferably formed such > that they accomplish closeness and a pore size that admits > self-flowing, i.e. a high flow rate. The pore size can > preferably be in the size of up to about 20 micrometer. One > filter element 18, 19 according to the present invention is > suitably composed of a screen cloth in the form of a closely > woven cloth, net, membrane or the similar, for example of > nylon or silk, which is securely moulded on the outermost edge > of an opening 14, 16. > > [0018] The first opening 14 may comprise a lid 20 for closing > of the opening when water has been filled. The second sealable > opening 16 can comprise a lid 22 which comprises indicator(s) > that may be set for indication that the water in the container > has been heated to a temperature of at least 60.degree. C. > after exposure by sunlight. The lid 22 can be provided with a > knob 24 that comprises two differently coloured surfaces 26, > 27, where one of the colours is set forward in order to > indicate that the purification procedure has been carried out. > The sides of the lids 20, 22 are suitably formed with sunlight > permeable sides. Also the neck of the openings 14, 16 are semi > UV-absorbing and semi UV-permeable in the embodiment shown in > the FIGS. 1A-B. > > [0019] A temperature indicator (not shown), such as a LCD > temperature indicator, may suitably be arranged centrally in > the container 2, which temperature indicator is arranged to > indicate when, and that, the water in the container 2 has > reached a temperature of at least 60.degree. C. after exposure > by sunlight. The temperature indicator can for instance be > rod-shaped and arranged from one of the sides 4, 6, 8-9, 10, > 12 directed against the centre of the container 2. Suitably > the temperature indicator is arranged to change colour when > the temperature reaches at least 60.degree. C. The temperature > indicator may suitably be provided with a memory such that a > reached maximum temperature during the sunlight exposure can > be checked afterwards. The temperature indicator may also be > reset. > > [0020] The UV-light kills DNA in the micro-organisms such > that a bactericidal effect is facilitated. An example of > dimensions of the container for a volume of 2 litres can e.g. > be 23.5 cm high, 17 cm wide and a thickness of 5 cm, but the > container may of course be of other dimensions. The sunlight, > that by means of the sunlight absorbing surface, the so called > absorber, converts the sunlight energy into heat energy and > rapidly raises the temperature of the water when exposed to > sunlight, whereby it also achieves a pasteurization effect > when the temperature has reached about 60.degree. C. During > about 10 minutes the temperature should be kept at 60.degree. > C. or higher. When the exposure of sunlight is completed, the > container should be cooled in the shadow or over the night > such that the water should reach a drinkable temperature. The > container according to the invention is suitably recyclable. > In that respect it is suitable that during a cycle of a day > and night, have at least three containers: one for collection > and purification, one for cooling and one for consumption. > Suitably also instructions of application should be present on > the side of the container, conveniently on the outside of the > container having the absorbing surface, e.g. in the form of a > drawn instruction that is easily understandable irrespective > of age, language or education. > > ---