سیستم آب شیرین کن خورشیدی SOLAR DESALINATION SYSTEM

This invention relates to improvements in solar desa lination systems, and is particularly concerned with a new and improved system which is adapted to be sub stantially self-contained and portable. With the increasing demands for both potable and irrigation water, and in view of the perennial scarcity of water in many areas adjacent to the ocean, considerable effort has been expended heretofore in attempts to con vert the ocean or sea water into fresh water by distilla tion or other evaporative means. In many such areas, there is ample sunshine most of the time. There have been numerous prior proposals to utilize solar energy for effecting sea water conversion. An example of one prior art proposal is found in U.S. Pat. No. 3,257,291 which uses a serpentine land based evaporator duct arrangement. Another prior example is found in U.S. Pat. No. 3,785,931 which provides a small capacity solar still. There is still much room for improving the technol ogy in solar desalination systems, and in particular to improve the spatial, ef?ciency and mobility, as well as other characteristics of such systems. The present in vention is directed to that end. Pursuant to the present invention, there is provided in a solar desalination system in which fresh water is de rived from sea water, an elongate solar ray collecting re?ector, which is adapted for focussing solar ray en ergy for heating a respective evaporator tube located at substantially the focal apex of the re?ector; means for delivering sea water to said evaporator tube; passage means for withdrawing vapor generated in said evapo rator tube; means for receiving vapor from said evapo rator tube and for condensing the vapor into fresh wa ter, and as an incident to the condensing developing at least some vacuum suction in said passage means toward said receiving and condensing means; means for withdrawing the fresh water condensate from said re ceiving means; and means for intermittently withdraw ing sea water concentrate from said evaporator tube. The present invention also provides a method of solar desalination for obtaining fresh water from sea water, and comprising focussing solar ray energy from an elongate re?ector onto and thereby heating a respective evaporator tube located at substantially the focal apex of the re?ector; delivering sea water to the evaporator tube, withdrawing vapor generated in the evaporator tube and condensing the vapor into fresh water in a receiving and condensing‘ means, as an incident to the condensing developing at least some vacuum suction for assisting in withdrawing the vapor generated in the evaporator tube, withdrawing the fresh water from the receiving and condensing means, and intermittently withdrawing sea water concentrate from the evapora tor tube. Other objects, features and advantages of the inven tion will be readily apparent from the following de scription of representative embodiments thereof, taken in conjunction with the accompanying drawings, al though variations and modi?cations may be effected without departing from the spirit and scope of the novel concepts embodied in the disclosure, and in which: FIG. 1 is a top plan view of apparatus providing a substantially self-contained solar desalination system embodying the invention. 1O 5 40 45 55 2 FIG. 2 is an enlarged fragmentary sectional detail view taken substantially along the line II-II of FIG. 1. FIG. 3 is an enlarged fragmental longitudinal sec tional elevational view taken substantially along the line III—III of FIG. 1. FIG. 4 is a fragmentary enlarged sectional detail view taken substantially along the line IV—IV of FIG. 3. FIG. 5 is a fragmentary sectional detail view similar to FIG. 4 but showing a modi?cation. FIG. 6 is a fragmentary elevational view, partially broken away and in section, showing a power unit adapted to be utilized with the system of FIG. 3; and FIG. 7 is a sectional elevational view taken substan tially along the line VII-—VII of FIG. 6. A solar desalination system 10 (FIG. 1) embodying the present invention is adapted to be constructed as a substantially self-contained unit which may be portable for transportation from place to place as desired. Desir ably the unit 10 is constructed as a ?oating platform and is provided with means adapted to capture solar ray energy over a substantial expanse. To this end, the unit 10 comprises a horizontal open grid platform-like frame 11 which desirably is formed from hollow bars of light weight material such as aluminum, ?berglass, or the like. In a preferred arrangement the frame 11 is of rect angular shape and is adapted to provide for mounting thereto a parallel array of a plurality of elongate trough like re?ectors 12 and associated respective parallel and substantially coextensive evaporator tubes 13 formed from any suitable material of acceptable heat transfer ef?ciency. Each of the re?ectors 12 is preferably provided with a generally upwardly facing parabolic re?ecting surface 14‘designed for ef?ciently focussing solar ray energy 15 onto the associated evaporator tube 13 which in each instance is located above and at substantially the focal apex of the re?ector. Desirably each of the evaporator tubes 13 has opposite closed ends which are ?xed to the open frame 10. Each of the re?ectors 12 has opposite end walls 15 which are provided at their central upper portions with bearing means comprising coaxial ?xed sleeves 17 slidably rotatably engaging the respective end portions of the tubes 13. Through this arrangement, the re?ectors 12 are adapted to be adjusted about the axes of the associated evaporator tubes 13 for efficient orientation having regard to the direction from which the solar rays project toward the re?ectors in the course of each day. Means are desirably provided for effecting such adjustment of the solar ray collectors or re?ectors 12, comprising, for example, linkage means 18 pivotally connected as at 19 to one side of the associated re?ector and pivotally connected as at 20 to a vertically movable rack 21 adapted to be reciprocated by means of a pinion 22 driven by a suitable timing mechanism within a cabi net 23. Clock controlled and like timers are available for this purpose. Thereby the attitude of each of the re?ec tors 12 is adpated to be automatically adjusted to follow the sun during the daily operating interval. Although for low volume fresh water req