Abstract:
The solar-powered distillation system is particularly adapted for small scale seawater distillation to produce fresh water. The system includes a single heat-absorbent evaporation panel having mutually opposed evaporation surfaces, the panel being contained within a single housing. Each side of the housing includes a lens panel. The lenses of each panel focus solar energy onto the respective surfaces of the evaporation panel. A mirror is positioned to each side of the housing to reflect solar energy onto the respective lens panels. Contaminated water enters the top of the housing to run down the surfaces of the evaporation panel. A fresh water collection pipe extends from the top of the housing to a collection tank. A scraper mechanism removes salt and/or other residue from the surfaces of the evaporation panel to allow the residue to be removed periodically from the bottom of the housing.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to apparatus and systems for the distillation and purification of liquids, and particularly to a small scale solar-powered distillation system suited particularly for the distillation of seawater to provide fresh water therefrom. 
     2. Description of the Related Art 
     Fresh water is a critical need in many parts of the world. Accordingly, a number of different methods have been developed in the past for processing seawater or other contaminated water that is not portable to provide fresh water. Settling and filtration serve to remove relatively large impurities. Filtration is also capable of removing smaller contaminants down to the size of bacteria, and perhaps even smaller particulates in certain cases. However, filtration systems capable of removing contaminants down to ionic size are quite costly, both in terms of manufacture and in maintenance as well. The very fine filters required for such operations require relatively high pressures for the reverse osmosis process to work, thus further increasing the costs of operation due to the power required. Periodic cleaning of the filtration elements is also required, adding further to the cost of operation. 
     An alternative means of water purification is distillation. Distillation works well in the removal of virtually all impurities from water. Distillation is used in many areas for the desalination of seawater. However, most distillation processes require considerable heat to produce sufficient evaporation. Most such processes involve heating the water to boiling in order to accelerate the evaporation process. This is particularly true of large-scale distilling operations. The requirement for such a large amount of heat is relatively costly. The evaporated water also leaves behind a residue (salt, etc.), that must be removed from time to time in order to retain reasonable operating efficiency. 
     As a result, the use of passive sources of energy (e.g., solar energy) has been developed to produce the required heat for evaporation. Additional apparatus is generally required to concentrate the solar energy in order to produce the required heat, but this can still be more economical than other water purification principles, particularly in smaller scale operations. In any event, the salt or other residue must still be cleaned occasionally from these devices in order to provide the required efficiency of operation. 
     An example of such a solar distillation system is found in Spanish Patent No. 1,072,040, published on May 11, 2010. No English abstract is provided, but the single drawing Figure illustrates an alembic for distilling sea water or the like. The alembic includes electrical heating elements in the base thereof with a series of magnifying lenses in one side of the device and a mirror in the opposite side, with the combination of magnified and reflected solar energy and electrical heating producing the distillation effect. 
     None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, a solar-powered distillation system solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The solar-powered distillation system provides a reasonably efficient distillation apparatus for small scale distillation processes. The efficiency is gained by providing a single, two-surfaced, heat absorbent evaporation panel in a single frame or housing, and transmitting solar energy to both sides of the single panel at least simultaneously. Lens panels are installed on opposite sides of the housing to transmit solar energy to both lens panels at least simultaneously, and mirrors are provided to orient solar energy toward each of the lens panels. A water supply pipe is provided along the top of the housing, and a distillate collection line extends from the top of the housing to a fresh water or distillate collection tank. 
     Salt and/or other residue that collects upon the surfaces of the evaporation panel is removed by scrapers. One such scraper operates along each surface of the evaporation panel. A motor and drive mechanism are provided to operate the scrapers periodically. The salt and/or other residue drops from the evaporation panel to collect in the bottom of the housing, where it is flushed or otherwise removed from time to time, as needed. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a solar-powered distillation system according to the present invention, illustrating its various components and their relationships to one another. 
         FIG. 2  is an exploded perspective view of the evaporator housing of the solar-powered distillation system of  FIG. 1 , illustrating various internal details thereof. 
         FIG. 3  is a detailed end elevation view in section of the assembled evaporator housing of the solar-powered distillation system of  FIG. 1 , illustrating the salt and residue scraper drive system. 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The solar-powered distillation system is a relatively compact system for small scale distillation of seawater or other contaminated water or liquid that only uses solar energy. While the solar-powered distillation system is primarily directed to the distillation of pure water from seawater, it will be seen that the system may be used to distill other liquids, if desired. 
       FIG. 1  of the drawings provides a perspective view of the entire solar-powered distillation system  10 .  FIGS. 2 and 3  provide an exploded perspective view and an elevation view in section of the housing  12  of the system and its internal componentry. The housing  12  is constructed or formed as a substantially square or rectangular structure having mutually opposed open faces, similar to a window frame or casement. The housing  12  is preferably formed of aluminum, although other metals or non-metallic materials (e.g., wood, plastic, etc.) may be used. The housing  12  includes an upper portion  14  and opposite lower portion  16  to support additional structure and components of the system  10 . 
     A heat-absorbent evaporation panel  18  is installed within the housing  12 , as shown in  FIGS. 2 and 3  of the drawings. The evaporation panel  18  is formed of a rigid sheet of material, e.g., aluminum or other suitable material, and is coated with a heat-absorbent material (e.g., anodized flat black, etc.) on both of its mutually opposed first and second surfaces  20   a  and  20   b . Alternatively, the panel  18  may be formed of a rigid sheet of black or dark plastic. The evaporation panel  18  is installed substantially vertically and centrally within the housing  12 , i.e., in a plane oriented parallel to the plane defined by the opposed sides and the opposed upper and lower portions  14  and  16  of the housing  12 , somewhat in the manner of a pane of glass installed in a window frame. The evaporation panel  18  divides the interior of the housing  12  into two substantially equal portions or evaporation chambers  22   a  and  22   b , as shown in  FIG. 3  of the drawings. 
     A lens panel is installed upon each side or face of the housing  12 , substantially parallel to one another and to the central evaporation panel  18 , as shown in the elevation view in section of  FIG. 3 . The housing  12 , its central evaporation panel  18 , and the two lens panels  24   a  and  24   b  form a bilaterally symmetrical assembly about a central plane P passing through the evaporation panel  18 , as shown in  FIG. 3 . The two lens panels  24   a ,  24   b  serve to close the interior of the housing  12  to prevent the escape of liquid vapor therefrom, except as described further below for distillate capture and removal. Each of the two lens panels  24   a ,  24   b  contains a large number of smaller separate individual lenses  26  to gather and focus sunlight into the interior of the housing  12 , and more specifically onto the black evaporation panel  18 , which heats the panel in order to facilitate evaporation of liquid deposited on the panel  18 . The lenses  26  may be placed in a seventeen-by-twelve matrix totaling 204 lenses, as in the example of  FIGS. 1 and 2 , or in some other suitable arrangement. The lenses  26  provide sufficient light-gathering power to heat the interior of the housing  12 , and specifically the evaporation panel  18  therein. Additional first and second mirrors  28   a ,  28   b  may be selectively placed to gather more light, and to focus or reflect the additional light onto the respective first and second lens panels  24   a  and  24   b , as shown in  FIG. 1 . 
       FIG. 1  also illustrates the general arrangement whereby liquid is delivered to the housing  12  and vapor condensation passes from the housing for collection. A liquid supply tank or container  30  contains the subject liquid (e.g., seawater, etc.) for distillation by the apparatus. A liquid supply pipe or line  32  extends from the upper portion  14  of the housing  12 , the distal end  34  of the supply pipe  32  being connected to the supply tank  30 . The supply tank  30  may be elevated, as shown in  FIG. 1 , to provide gravity flow, and thus obviate any need for pumps and/or additional complexity. Conventional components, such as shutoff valves, etc., are not shown for clarity in the drawing. A distillate collection tank or container  36  receives the condensed, distilled water or other liquid from the housing  12 . A distillate collection pipe or line  38  extends from the upper portion  14  of the housing  12 , the distal end  40  of the distillate collection pipe  38  being connected to the distillate collection tank  36 . 
       FIGS. 2 and 3  provide further detail of the means for introducing water or other liquid into the housing  12 . The upper portion  14  of the housing  12  includes a plurality of liquid inlet passages  42  extending therethrough in a linear array. An elongate channel  44  is installed atop the upper portion  14  of the housing  12 , directly over the inlet passages  42 . The channel  44  includes a plurality of transfer passages  46  formed therethrough, located essentially directly over the inlet passages  42  of the upper portion  14  of the housing  12  to communicate therewith. The liquid supply pipe  32  has a liquid outlet portion or manifold  48  depending therefrom, and aligned over the channel  44 . The liquid outlet portion  48  of the liquid supply pipe  32  includes a plurality of outlet passages  50  therethrough. 
     Thus, seawater (or other liquid) may flow from the supply tank  30  and through the liquid supply pipe  32  to its outlet portion  48 , and then flows through the outlet passages  50  therein and into the channel  44  directly therebelow. The liquid flows through the transfer passages  46  of the channel  44  to pass through the inlet passages  42  in the upper portion  14  of the housing  12 , to drip or flow down the two opposed surfaces  20   a  and  20   b  of the central evaporation panel  18 . After evaporating on the evaporation panel  18 , the liquid vapor passes into the distillate collection pipe  38 , where it condenses and flows into the distillate collection tank or container  36 . 
     It will be seen that water (or other liquid) containing various suspended and/or dissolved solids will deposit those impurities upon the evaporation panel  18  as the liquid evaporates therefrom. Accordingly, some means must be provided for the periodic removal of such deposits or residue from the two faces  20   a  and  20   b  of the evaporation panel  18 . This is accomplished in the solar power distillation system  10  by mechanical scrapers  52   a ,  52   b  movably installed upon the respective surfaces  20   a  and  20   b  of the evaporation panel  18 . 
       FIG. 3  illustrates the two scrapers  52   a ,  52   b  and their drive means. An electric motor  54  or other suitable driver is installed upon the housing  12 . The motor  54  receives its power from any suitable conventional source (solar power and storage battery, power grid, etc.). The motor  54  periodically operates to turn a drive sprocket  56 , which, in turn, drives a chain  58  that extends the vertical depth of the housing  12  around an idler sprocket  60 . The two sprockets  56  and  60  and the scraper drive chain  58  are disposed along one vertical edge of the evaporation panel  18  between the panel  18  and the side of the housing  12 . Corresponding ends of the two scrapers  52   a  and  52   b  are connected to the chain  58  on opposite sides of the evaporation panel  18  so that the scrapers  52   a ,  52   b  extend laterally from the chain  58 . 
     Operation of the motor  54  results in one side of the chain  58  rising to lift one of the scrapers, e.g., the first scraper  52   a , up the first surface  20   a  of the evaporation panel  18 , while simultaneously causing the opposite side of the chain  58  to descend, thus drawing the opposite second scraper  52   b  downward over the second face  20   b  of the evaporation panel  18 . The drive mechanism illustrated in  FIG. 3  and described herein serves as a reasonably simple and reliable means for removing scale and residue from the two faces  20   a  and  20   b  of the evaporation panel  18 . It will be seen that the two scrapers  52   a ,  52   b  need not remain directly opposite one another at all times, or move in the same direction with one another. However, other mechanisms, e.g., threaded screw drives, etc., may be used as desired. Additional structure may be provided to support the opposite ends of the two scrapers  52   a  and  52   b , i.e., the ends opposite their attachments to the drive chain  58 . Such structure is not illustrated for clarity in the drawings. 
     Scale and/or other residue removed from the evaporation panel  18  by the above-described scraper system falls into the lower portion  16  of the housing  12 , and collects in a residue collection trough  62 . A residue cleanout  64  is provided at each end of the lower portion  16  of the housing  12 . Scale and/or other deposits or residue, either dry or in the form of a brine or other thick liquid, may be removed from the trough  62  of the housing  12  by removing either or both cleanout caps  66  from their respective residue cleanouts  64  to access the trough  62 . The deposits or residue may be flushed or otherwise removed from the residue collection trough  62  via the open residue cleanouts  64  communicating with the trough  62  and interior of the housing  12 . 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.