Abstract:
A distillate system, especially of the sea water, by using the sun as heat source and the sea water as cold source, falling the work pressure to the boiling point of the sea water between the temperature generated by the sun and the temperature of the sea water. The sea water and the fresh water are entered/removed to/from the distillation system at the same time, by compensating the pressure differences.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present invention is based on the Spanish application of patent no. P200200733, dated Mar. 18, 2002, that is priority. Following patents are related with the present invention:  
         [0002]    U.S. Pat. No. 6,494,995. A floating solar cell, being created a partial vacuum in the solar cell.  
         [0003]    U.S. Pat. No. 6,391,162. A desalination system utilizing solar energy provided with a solar heat collector, a heat exchanger, a condenser and a raw water tank. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0004]    They are well known the vacuum distillation systems. Regarding the distillation of sea water, said vacuum is between 0.6 and 0.9 at. of work pressure, because lower pressures mean to spend a lot of energy for remove out the fresh water from the distillation apparatus.  
           [0005]    The previous implies that the work temperature is far regarding the possibilities of the solar heat. So, to boil the sea water using the sun heat, the work pressure would be between the 0.03 and the 0.07 at.  
         BRIEF SUMMARY OF THE INVENTION  
         [0006]    This invention proposes a system that allows very low work pressures and by this, the efficient use of the solar heat, or another heat sources of low temperature, according with the following.  
           [0007]    The sea water is evaporated into an evaporation tank by the solar heat. The vapor is condensed into a condensation tank by the relatively cool sea water. Said tanks being connected by a vapor conduit. The set of the tanks and the conduit being isolated from the external atmosfhere. The sea water would boil at the temperature of the evaporation tank and would condensate at the temperature of the sea water. By this the work pressure is lowered by a vacuum pump.  
           [0008]    To remove the fresh water from the condensation tank, a extraction pump is provided. Said pump would spend a lot of energy because the fresh water goes from a pressure of 0.05 at. (by example), to a pressure of 1 at.  
           [0009]    But, when the sea water enter, the sea water goes from a pressure of 1 at. to a pressure of 0.05 at. If said sea water is drove from the sea to the evaporation tank through a turbine with a capacity similar to the extraction pump, and the shafts of the turbine and the extraction pump are connected, an important amount of energy could be saved.  
           [0010]    Naturally the system is suitable to be applied to another distillation system. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0011]    [0011]FIG. 1. A general distillation system.  
         [0012]    [0012]FIG. 2. The distillation system with several distilled products.  
         [0013]    [0013]FIG. 3. The distillation system to obtain fresh water and salt from the sea water.  
         [0014]    [0014]FIG. 4. Transversal view of an evaporation tank.  
         [0015]    [0015]FIG. 5. Transversal view of an evaporation tank for obtain only fresh water.  
         [0016]    [0016]FIG. 6. Travenrsal view of two evaporation tanks to obtain different salts.  
         [0017]    [0017]FIG. 7. The distillation system on a floating platform.  
         [0018]    [0018]FIG. 8. Transversal view of an evaporation tank with a container for the salt.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    [0019]FIG. 1 illustrates a very general distillation system with a evaporation zone  1  and a condensation zone  2 . The zone  1  comprises a first thermometer  3 , and a first capacity sensor  4 , while the zone  2  comprises a second thermometer  5  and a second capacity sensor  6 . The whole evaporation system has a nanometer  7 , a vacuum pump  8  and a control unit  9  of said vacuum pump.  
         [0020]    The evaporation system is fed through a valve  10  and a turbine  11 , controlled by the first capacity sensor  4 , being emptied through a valve  12  and a extraction pump  13 , controlled by the second capacity sensor  6 . The turbine and the extraction pump having a common shaft  14  and a motor  15  (by example electric). The control of the turbine and the extraction pump is through the motor  15 , said motor is fed by a first switch  16 , controlled by the first capacity sensor  4 , and a second switch  17 , controlled by the second capacity sensor  6 .  
         [0021]    The control unit of the vacuum pump activates the vacuum pump while the internal pressure of the system is upper the desirable value according the reading of the first and second thermometers, and the nanometer.  
         [0022]    [0022]FIG. 2. If there are several distilled products  2 ,  2   a ,  2   b , they must be the same number of extraction pumps  13 ,  13   a ,  13   b as distilled products. All the extraction pump must be assembled on the same shaft  14  and the relative volume between the pumps must be the same that its connected distilled products. In addition, for each additional extraction pump it must have one additional capacity sensor  6 ,  6   a ,  6   b  in the condensation zone and one additional switch in series to feed the electric motor  17 ,  17   a ,  17   b.    
         [0023]    [0023]FIG. 3 shows a sea water distillation. The evaporation zone is a evaporation tank placed at the sun  1   c  and fed by the sea water, while the condensation zone is a submerged condensation tank  2   c,  its walls being thermally conductors. The capacity sensor  4  is a buoy that activates the valve  10  and the switch  16  when the same falls a prefixed value, until said buoy raises another prefixed value. The capacity sensor  6  is a buoy that activates the valve  12  and the switch  17  when the same raises a prefixed value, until said buoy falls another prefixed value.  
         [0024]    The capacity of the turbine  11  and the extraction pump  13  are substantially the same.  
         [0025]    A vapor conduit  18  links the evaporation tank  1   c  and the condensation tank  2   c , being the vacuum pump  8  on said conduit, and having said conduit a vapor valve  19 . Said vapor valve  19  can be useful when the evaporation tank would be emptied, because closing said vapor valve, the vacuum of the condensation tank is preserved.  
         [0026]    Furthermore, the FIG. 3 also shows a densimeter  20  for control purposes, by example being connected to an alarm.  
         [0027]    [0027]FIG. 4 represents a transversal view of the evaporation tank  1   c , showing a transparent cover  21 , isolated walls  22  and the precipitated salt  23 .  
         [0028]    [0028]FIG. 5 illustrated the evaporation tank  1   c  when the salt is not desired. The densimeter  20  controls the vapor valve  19  and a marine valve  24  which connects the evaporation tank with the sea. When the densimeter  20  raises a prefixed value closes the valve  19  and opens said marine valve  24 , then the sea water penetrates into the condensation tank, until a prefixed amount of salt is dissolved. Then the marine valve  24  is closed and the vapor valve  19  is opened.  
         [0029]    [0029]FIG. 6. It is possible to obtain several salt types by putting several consecutive evaporation tanks. By this, a second evaporation tank is connected with the first evaporation tank through a second input valve  10   b,  the second evaporation tank with the third with a third valve  10   c , . . .  
         [0030]    The second input valve  10   b  is controlled at the same time by the densimeter of the first evaporation tank  20  and the buoy of the second evaporation tank  4   b , while the third input valve l 0   c  is controlled by the densimeter of the second evaporation tank  20   b  and the buoy of the third evaporation tank.  
         [0031]    Then, each input valve is opened when its densimeter and its buoy reach a prefixed value.  
         [0032]    [0032]FIG. 7 represents the distillation sea water system assembled to a marine platform, showing the evaporation tank  1   c  and the condensation tank  2   c , a floating  25 , a device to pick up power from the sea waves  26  and a anchorage  27  to the sea bottom.  
         [0033]    [0033]FIG. 8 shows the evaporation tank  1   c  with a mobile container  28  to remove the salt.  
         [0034]    Regarding this invention, a turbine is a device which transforms pressure differences in mechanical energy and a pump is a device which transforms mechanical energy in pressure differences. There are a lot of turbine and pump types, but the set of turbine—pump—common shaft—motor shaft—motor must be compatible. So, they are possible the following configurations:  
         [0035]    a rotating turbine, a rotating pump, a rotating common shaft, a rotating motor shaft and a rotating motor,  
         [0036]    a piston turbine, a piston pump, a oscillation common shaft, a rod-crank mechanism and a rotating motor,  
         [0037]    a rotating turbine, a rotating pump, a rotating common shaft, a rod-crank mechanism and a piston motor,  
         [0038]    a piston turbine, a rotating pump, the common shaft being a rod-crank mechanism, a rotating motor shaft and a rotating motor,  
         [0039]    The previous paragraph are not represented because all said devices are well known in the art.