This invention relates to an apparatus for recovering simultaneously fresh water and salt or saline solution by direct collection of solar energy by means of special energy elements.

The invention has the object to bring about an apparatus, which yields higher returns at a lower price compared with conventional apparatuses operated with oil, electricity or the like. The charact- erizing features of an apparatus according to the invention become apparent from the attached claims.

The invention is described in greater detail in the following, with reference to the accompanying drawings, in which

Fig. 1 is a front view of a flow element comprised in an apparatus according to the invention,

Fig. 2 is a lateral view of the flow element,

Fig. 3 is a front view of a clamping element comprised in the flow element, Fig. 4 is a lateral view of the clamping element, Fig. 5 shows an inlet (or outlet) in the flow element with a laid-in clamping element, and Fig. 6 shows an apparatus comprising several flow elements accord¬ ing to Figs . 1 -2.

The flow element according to Figs . 1 -2 consists of two thin foils 10 and 20, which are jointed in longitudinal direction of the flow element by intermittent welding in several places in the transverse direction, so that the flow element includes a plurality of longitudinal gaps for water transport. In Fig. .1 three' such gaps are indicated to the left and one to the right, . their reference numerals being 11 , 12, 13, 14. The term intermittent welding is to be understood so that the welding joints are discontinuous . A welding joint is designated by 15, and a distance between two joints is designated by 16. It is pos sible in principle to weld continuous joints, but discontinuous joints give rise to a certain turbulence at the water flow. The flow element is connected at one end to two inlets 18 and at its other end to two outlets 17. Between the outlets 17 a clamping ele-

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ment 21 -22 is provided, the ends of which are secured in the inlets 18, and the foils 10, 20 are so laid about the clamping element, that the clamping element is located between the foils . The clamping ele ment appears more clearly from Figs . 3 -4. It has the form of a T with an arc -shaped roof 21 and a straight remaining portion 22. The manner in which the clamping element is secured in an outlet 17 and, respectively, inlet 18 appears more clearly from Fig. 5, which sho an outlet 17 from the si-de with two proj ections 171 and, re spectively 172 on the inside of the outlet. The end of the remaining straight po tion 22 is pres sed in between said proj e ctions 171 and 172.

The flow element is connected in the same manner to the two inlets 18, and the foils 10, 20 are laid about a clamping element identical with the element 21 -22. The flow element may have a width of about 4 m and a length of 10 m, the distance between a welding joint and th nearest adjacent joint may be 3 to 4 cm, and the diameter of a flow gap at a system filled with water may be 2 to 3 cm.

An apparatus according to the invention comprises a great number of flow elements of the kind described above. Said flow elements con¬ stitute special energy elements for direct absorption of s olar energy Each of these energy elements is at one end attached mechanically to inlets for sea water and at its remaining end attached mechanically to inlets on an evaporation chamber for recovery of fresh water in known manner .

In the apparatus according to Fig. 6 the ener gy elements are divided into several units . A first one of said units compris e s a plurality of energy elements 61 1 , 612, 6ln connected in parallel, which elements are coupled mechanically on the inlet side to an inlet 613 for surface water from the s ea and on the outlet side are coupled mechanically t an inlet 614 on a first evaporation chamber 615. An outlet 616 on said fir st evaporation chamber 615 is coupled mechanically to an inle 623 on a second unit of said units , which unit consists of a plurality energy elements 621 , 622, 62n connected in parallel. Said unit is coupled mechanically on the outlet side to an inlet 624 on a second evaporation chamber 625. About twenty units with ener gy elements are coupled mechanically in the manner des cribed to about twenty evaporation chamber s, so that a last evaporation chamber 63n on the

inlet side 634 is coupled to a last unit of said units, and on the outlet side 636 is coupled to a conventional salt-works 637 for evaporation of the residual water amount in the water pumped up from the sea.

The evaporation chambers are designed in a manner known per se, for example according to SE-PS 387 927, comprising a first plurality of plane parallel and vertically arranged plates poured on with relative¬ ly warm sea water, and .a second plurality of plane parallel and vertically arranged plates poured on with relatively cold fresh water, • and coolers designated in Fig. 6 by 618, 628, 638. The water fed in to an evaporation chamber from a unit with energy elements has a temperature of about 70 C, and the water discharged from the evaporation chamber has a temperature of, for example, about 30 C or lower. At a temperature difference of about 40 C bet¬ ween the plates in the evaporation chamber, and at 25 evaporation chambers connected in series according to Fig. 6, 850 litre per 1000 litre sea water fed in pass over to the fresh water side. This implies that the salt content on the outlet side 636 of the last evaporation chamber amounts to about 23 %. The remaining water amount evaporates in the salt-works 637. The material in the energy elements preferably is black plastic mate¬ rial, which is covered by a foil of transparent plastic material in order to reduce convection losses between energy elements and ambient air . It is to be pointed out in this connection, that the in¬ formation in the above des cription and the attached claims that the flow elements consist of two foils, is to be understood so that two defining walls of the flow elements consist of foils . Thus, in principle nothing obstructs each foil wall to consist of several partial foils.