Abstract:
This invention proposes a domestic apparatus for water purification, which is based on evaporation-condensation principle and operates under atmospheric pressure. Evaporation process is performed in this apparatus by simple evaporation from the surface of hot tap water without boiling process. The purifier can be easily disassembled and cleaned from scaling.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to the field of domestic apparatuses for water purification. It is known that quality of tap water in many countries doesn&#39;t satisfy householders. Tap water has usually relatively high concentration of mineral salts, organic substances and microorganisms. There are some ways to overcome this problem.  
         [0002]     The first one is supply to the householders bottled spring water, however, this way is very expensive. In addition, bottled water can readily become contaminated by airborne bacteria and viruses during dispensing process by the introduction of ambient air drawn inside the bottle as the water is dispensed.  
         [0003]     For this reason different type of tap water purifiers are widely presented in domestic application.  
         [0004]     The main type of such purifiers is related to filtration devices. In the first period of a filter operation a significant part of contaminants of the tap water is held in the filter. However, in the process of contaminants&#39; collection in the filter, its purifying ability is decreased.  
         [0005]     The purification systems based on reverse osmosis are very expensive.  
         [0006]     For all these reasons the domestic tap water purifiers are very attractive. These devices operates on the base of evaporation-condensation principle and include usually a boiler provided with an electrical heating element (the boiler generates a steam from tap water), a condenser for steam condensation, and a distilled water storage.  
         [0007]     There are some the USA patents, which disclose different constructions of such devices (see for example U.S. Pat. Nos. 5,762,762, 5,536,375, 4,943,353, 4,805,692). However all these patents describe devices with boilers which operate under certain pressure with application of boiling process.  
         [0008]     Such devices do not provide required safety, expensive and are not suitable for cleaning the scaling formed on the internal walls of their boilers.  
         [0009]     In addition, several designs of these patents incorporate demisters for separation of droplets contained in the generated steam as the result of boiling process.  
         [0010]     All these circumferences make these devices very expensive and cause difficulties in their maintenance.  
       BRIEF SUMMARY OF THE INVENTION  
       [0011]     This invention proposes a tap water purifier, which operates under atmospheric pressure. Evaporation process is performed in this device by simple evaporation from the surface of hot tap water without boiling process. It allows achieving several advantages:  
         [0012]     1. It is possible to combine evaporation and condensation processes in one chamber, which operates at atmospheric pressure. It permits in turn to construct a safely purifier with sufficiently thin walls. Such construction can be cheap and of low weight.  
         [0000]     2. Since the evaporation process occurs without boiling, it is not accompanied with mist formation and, therefore, a demister designed to prevent condensation of vapors with droplets of tap water is not needed.  
         [0000]     3. It is possible to construct the purifier with two or more evaporation-condensation sub-units, when in the following sub-unit the heat of vapors&#39; condensation is used for evaporation of an additional portion of tap water.  
         [0000]     4. The purifier can be easily disassembled and cleaned from scaling. In addition, rate of scaling formation for evaporation without boiling will be significantly lower.  
         [0013]     The proposed purifier comprises some main units.  
         [0000]     A distillate container has the rectangular horizontal cross-section, this container is provided with bottom legs, which should be positioned on a table.  
         [0014]     This distillate container is provided with a tap positioned on the lower section of its front wall; the tap serves for dispensing the distilled water.  
         [0015]     In addition, the distillate container can be provided with a level gauge showing the level of distillate in this container. It is possible to install a small water pump on the outer surface of the distillate container; this water pump serves for dispensing the distillate to a consumer. The distillate container is covered by an upper metal horizontal partition, which is provided with one lateral slot at its left extreme section and with two smaller lateral slots at its right section.  
         [0016]     These slots serve for circulation of the cooled air via the upper space of the distillate container and for introduction of the distillate into the distillate container.  
         [0017]     Heating the tap water is performed by an electrical heater, which has a form of a flat coil and is positioned in a metal housing. In addition, there is a layer of thermal insulation situated below this flat coil in the metal housing (the flat coil can be separated from the layer of thermal insulation by an additional metal partition). The lower horizontal side of the housing is installed on the central section of the upper horizontal partition of the distillate container. In addition, the flat coil of the electrical heater can be joined with a metal sheet in order to provide heating with higher homogeneity.  
         [0018]     An external housing of a unit, which is intended to perform evaporation of the tap water and following condensation of formed vapors, is installed on the upper edge of the distillate container; this external housing has a form of a rectangular box. An evaporation sub-unit itself is formed by combination of the front and back walls of the external housing, two vertical partitions situated perpendicularly to these front and back walls, and the upper wall of the housing of the electrical heater, which plays a role of the bottom.  
         [0019]     The external housing is covered at the top with a cover. There is a certain gap between this cover and the upper edges of the aforementioned vertical partitions. This gap serves for removal of vapors obtained in the evaporation sub-unit to a condensation sub-unit, which is formed between one vertical partition and the lateral adjacent wall of the external housing, and introduction of heated air from the gap between the second vertical partition and the opposite lateral wall of the external housing into the internal vapors&#39; space in this evaporation sub-unit.  
         [0020]     The central area of the cover is provided with an inlet connection with a plug; it is applied for filling the evaporation sub-unit with the tap water. Additionally, the evaporation sub-unit can be connected with a water cock in order to perform delivery of tap water automatically from the water main, in this case the evaporation sub-unit is provided as well with a float valve.  
         [0021]     The central section of the front wall of the external housing, which serves as well as the front wall of the evaporation sub-unit, is provided with a tap for removal of residues of the tap water with concentrated impurities, and with a level gauge showing the tap water level in the evaporation sub-unit.  
         [0022]     A heat-exchanging plate with fins directed inwards is installed on the inner side of the right lateral wall of the external housing in the gap between this wall and the right vertical partition. Another finned heat-exchanging plate is F installed on the outer side of this wall adjacently to the first heat-exchanging plate. In addition, a fan (or a set of fans) serves for blow of the surrounding air through the fins of the outer heat-exchanging plate.  
         [0023]     The aforementioned upper horizontal partition of the distillate container is provided with a flanging and an opening; this section of the horizontal partition is located beneath the inner heat-exchanging plate; in such a way this section of the upper horizontal partition forms a tray. The opening in this tray serves for installation of a filter for performance additional purification of the distillate mainly from chlorine and organic volatile impurities. In addition, this filter can contain minerals with low solubility in water for improvement of taste of the distillate.  
         [0024]     The upper cover of the external housing can be supplied with an opening and a plug, this opening is intended for installation of a small bottle with minerals&#39; solution, this solution added to the distillate during a certain period and serves for improvement of its taste.  
         [0025]     The outer side of the left partition is provided in turn with an additional heat-exchanging plate with fins directed inward the gap between the left vertical partition and the left lateral wall of the external housing.  
         [0026]     The described water purifier operates in the following manner:  
         [0027]     The power of the electrical heater is chosen is such a way, that specific heat flux transferred via the horizontal cross-section of the evaporation sub-unit does not exceed a specific value (about of 5 W/cm 2 ). For such low value of heat flux, the tap water is evaporating in the evaporation sub-unit without boiling process. It obviates the need of a demister application.  
         [0028]     The hot water vapors with the air contained in the evaporation sub-unit are moving to the fins of the cooled inner heat-exchanging plate. After vapors&#39; condensation on these fins and accompanied cooling the air, this air is descending via the right slots in the upper horizontal partition of the distillate container into its inner space. Then the air is ascending via the slot in the left lateral section of the upper horizontal partition into the gap between the left lateral wall of the external housing and the left vertical partition.  
         [0029]     The left heat-exchanging plate, which is transferring heat from the external wall of the evaporation sub-unit into the gap between this wall, heats the air in this gap. Thereafter the heated air enters into the upper space of the evaporation sub-unit and it is mixed with new portions of vapors of the tap water before its passing to the inner cooling heat-exchanging plate.  
         [0030]     In order to intensify air circulation in the circle described above, it is possible to apply (additionally or instead of the left finned heat-exchanging plate) a fan, which is positioned in the gap between the left vertical partition and the left lateral wall of the external housing.  
         [0031]     In another version of the purifier, the left vertical partition, the left slot in the upper horizontal partition and the left heat-exchanging plate are not used and there is a relatively big distance between the upper edge of the right vertical partition and the cover. Such distance allows locating the inner and outer heat-exchanging plates on the right wall of the external housing at the level of the gap between the upper edge of the right vertical partition and the cover. This design ensures as well removal of cold air from the fins of the inner heat-exchanging plate.  
         [0032]     The upper wall of the housing of the electrical heater can be provided with the vertical fins in order to increase the heat-exchanging surface in the evaporation chamber and to prevent boiling of the tap water.  
     
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS THE DRAWINGS  
       [0033]     Preferred embodiments of the invention are described below by way of example with reference to the accompanying drawings, in which:  
         [0034]      FIG. 1  is a middle cross-sectioned view of a purifier in parallel to its front plan;  
         [0035]      FIG. 2  is a cross-sectional view of the purifier taken on line A-A perpendicularly to the front plan;  
         [0036]      FIG. 3  is a cross-sectional view of the purifier taken on line B-B perpendicularly to the front plan;  
         [0037]      FIG. 4  is a cross-sectional view of the purifier taken on line C-C in parallel to the horizontal plane;  
         [0038]      FIG. 5  is a middle cross-sectional view of a purifier in parallel to its front plan, when the condensation unit of this purifier is arranged on the lateral wall of the distillate container.  
         [0039]      FIG. 6  is a top view of an electrical heater.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0040]      FIG. 1  is the middle cross-sectional view of a tap water purifier in parallel to its front plan.  
         [0041]     It comprises a distillate container  101  which has the rectangular horizontal cross-section, this container is provided with bottom legs  102 , which should be positioned on a table.  
         [0042]     Container  101  is covered by an upper metal horizontal partition  103 , which is provided with one lateral slot at its left extreme section and with two smaller slots at its right section. These slots serve for circulation of cooled air via the upper space of the distillate container.  
         [0043]     An electrical heater  104  in the form of a flat coil is positioned in a metal housing  105 . In addition, there is layer  106  of thermal insulation situated below this flat coil in the metal housing  105  (the flat coil is separated from the layer of thermal insulation by an additional metal partition  107 ). The lower horizontal side of the metal housing  105  is installed on the central section of the upper horizontal partition  103  of the distillate container. In addition, the coil of the electrical heater  104  is joined with a metal sheet  108  in order to provide heating with higher homogeneity.  
         [0044]     An external housing  109  of evaporation and condensation sub-units is installed on the upper edge of the distillate container  101 ; this external housing has a form of a rectangular box. The evaporation sub-unit itself is formed by combination of the front and back walls of the external housing, two vertical partitions  110  and  111  situated perpendicularly to these front and back walls, and the upper wall  112  of the metal housing  105  of the electrical heater  104 .  
         [0045]     The external housing  109  is covered at the top with cover  113 . There is a certain gap between this cover and the upper edges of the aforementioned vertical partitions  110  and  111 .  
         [0046]     This gap serves for removal of vapors obtained in the evaporation sub-unit to the condensation sub-unit, which is formed between the first vertical partition  110  and the lateral adjacent wall  114  of the external housing  109 , and introduction of heated air from the gap between the second vertical partition  111  and the opposite lateral wall  115  of the external housing into the internal vapors&#39; space in this evaporation sub-unit.  
         [0047]     The central area of the cover  113  is provided with an inlet connection  116  with plug  117 ; they are applied for filling the evaporation unit with the tap water.  
         [0048]     A heat-exchanging plate  118  with fins  119  directed inwards is installed on inner side of the right lateral wall  115  of the external housing in the gap between this wall and the right vertical partition  111 . Another heat-exchanging plate  120  with fins  121  is installed on the outer side of this wall adjacently to the first heat-exchanging plate. In addition, fan  122  (or a set of fans) serves for blow of surrounding air through fins  121  of the outer heat-exchanging plate  120 . The aforementioned upper horizontal partition  103  of the distillate container is provided with flanging  123  and opening  124 ; this section of the horizontal partition is located beneath the inner heat-exchanging plate  118  and its fins  119 ; in such a way this section of the upper horizontal partition forms a tray. Opening  124  in this tray serves for installation of filter  125  for performance additional purification of the distillate mainly from chlorine and organic volatile impurities. In addition, this filter can contain some mineral substances; these substances are dissolving slowly in distillate and improve its taste.  
         [0049]     The upper cover  113  of the external housing can be supplied with opening  126  which serves for installation a small bottle  127  with minerals&#39; solution, this solution is added to the distillate during a certain period and serves for improvement of its taste.  
         [0050]     The outer side of the left partition  110  is provided with an additional heat exchanging plate  128  with tins  129  directed inward the gap between the left vertical partition  110  and the left lateral wall  115  of the external housing  109 .  
         [0051]      FIG. 2  presents a cross-sectional view of the purifier shown in  FIG. 1 , this cross-sectional view is taken on line A-A perpendicularly to the front plan.  
         [0052]     The cross-sectional view comprises a distillate container  201  with bottom legs  202  and an upper horizontal partition  203 . The front wall of the distillate container  201  is provided at its lower section with tap  204  for dispensing the distillate. An electrical heater  205  in the form of a flat coil is positioned in a metal housing  206 . In addition, there is layer  207  of thermal insulation situated below this flat coil in the metal housing  206  (the flat coil is separated from layer  207  of the thermal insulation by an additional metal partition  208 ).  
         [0053]     The lower horizontal side of the metal housing  206  is installed on the central section of the upper horizontal partition  203  of the distillate container. In addition, the coil of the electrical heater  205  is joined with a metal sheet  209  in order to provide heating with higher homogeneity.  
         [0054]     An external housing  210  of evaporation and condensation sub-units is installed on the upper edge of the distillate container  201 , this external housing has a form of a rectangular box. The cross-sectional view A-A shows front and back walls  211  and  212 , and bottom  213  of the evaporation sub-unit, which plays at the same time a role of the upper wall of the housing of the electrical heater  205 .  
         [0055]     The front wall  211  is provided with a level gauge  214  and tap  215 , which serves for discharging the tap water with concentrated impurities. The external housing  210  is covered at the top with cover  216 . The central area of cover  216  is provided with an inlet connection  217  and plug  218 ; they are applied for filling the evaporation sub-unit with the tap water.  
         [0056]      FIG. 3  shows a cross-sectional view of the purifier taken on line B-B perpendicularly to the front plan (see  FIG. 1 ). It comprises a distillate container  301  with bottom legs  302  and an upper horizontal partition  303  with flanging  304 . The central area of this section of the upper horizontal partition  303  is provided with opening  305  and a detachable filter  306 . In addition, this detachable filter can contain minerals with low solubility in water in order to improve taste of the distillated water.  
         [0057]     A heat-exchanging inner plate  307  with fins  308  is installed on a lateral wall  309  of a condensation sub-unit  310 . The condensation sub-unit  310  is covered from aloft by cover  311 , which is common for the whole external housing; the section of cover  311 , which is related to the condensation sub-unit, is provided with opening  312  serving for installation a small bottle  313  with minerals&#39; solution, this solution is added to the distillate during a certain period and improves its taste.  
         [0058]      FIG. 4  shows a cross-sectional view of the purifier taken on line C-C in parallel to the horizontal plane (see  FIG. 1 ). It comprises an evaporation sub-unit  401  formed by the central sections of front and back walls  402  and  403 , and by left and right vertical partitions  404  and  405 . A dispensing tap  406  is installed at the lower section of the front wall  402  forming this evaporation sub-unit.  
         [0059]     A condensation sub-unit  407  is formed by extreme right sections of the front and back walls  402  and  403 , the vertical right partition  405  and a right lateral wall  408  of the external housing. A heat-exchanging plate  411  with fins  412  is installed on the external side of the vertical left partition  404 . An inner heat-exchanging plate  409  with fins  410  is installed on the internal side of the right lateral wall  408 . An external heat-exchanging plate  413  with fins  414  is installed on the external side of the right lateral wall  408 . In addition, some fans  415  are installed beneath the external heat-exchanging plate  413 .  
         [0060]     The whole outer construction (the external heat-exchanging plate  413  and fans  415 ) is covered by casing  416 , which is provided with upper and lower slots.  
         [0061]      FIG. 5  is the middle cross-sectional view of a purifier in parallel to its front plan, when its condensation sub-unit is arranged on the lateral wall of a distillate container.  
         [0062]     It comprises a distillate container  501 , which has the rectangular horizontal cross-section; this distillate container is provided with bottom legs  502 , which should be positioned on a table. The distillate container  501  is covered by an upper metal horizontal partition  503 , which is provided with one lateral slot at its left extreme section and with a lateral slot at its right extreme section. These slots serve for circulation of cooled air via the upper space of the distillate container  501 .  
         [0063]     An electrical heater  504  in the form of a flat coil is positioned in a metal housing  505 . In addition, there is layer  506  of thermal insulation situated below this flat coil in the metal housing  505  (the flat coil is separated from the layer of thermal insulation by an additional metal horizontal partition  507 ). The lower horizontal side of the metal housing is installed on the central section of the upper metal horizontal partition  503  of the distillate container.  
         [0064]     The coil of the electrical heater  504  is joined with a metal sheet  508  in order to provide heating with higher homogeneity.  
         [0065]     An inner heat-exchanging plate  509  of a condensation sub-unit is installed on the right lateral wall  510  of the distillate container. In addition, there is a vertical partition  511 , which is installed on the upper metal horizontal partition  503  in order to ensure complete condensation of vapors on fins  512  of the inner heat-exchanging plate  509 .  
         [0066]     An outer heat-exchanging plate  513  with fins  514  is installed on the outer side of this lateral wall adjacently to the inner heat-exchanging plate. In addition, fan  515  or a set of fans serves for blow of the surrounding air through fins  514  of the outer heat-exchanging plate  513 .  
         [0067]     An evaporation sub-unit of the purifier comprises an external housing  516  with the lateral left and right walls  517  and  518  (front and back walls are not shown), and the left and right vertical partitions  519  and  520 . Cover  521  is provided with an inlet connection  522  and plug  523 , which serve for filling the evaporation sub-unit with the tap water. This evaporation sub-unit is installed on the upper edge of the distillate container by flanging  524 .  
         [0068]     The outer side of the left partition  519  is provided with an additional heat-exchanging plate  525  with fins  526  directed inward the gap between the left vertical partition  519  and the left lateral wall  517  of the external housing  516 . In addition, there is fan  527  (or fans) installed in the lower section of the gap between the left vertical partition  519  and the left lateral wall  517 .  
         [0069]      FIG. 6  is the front view of an electrical heater. It comprises an electrical flat heating coil  601 , electrical wires  602  with terminals  603 , and a metal sheet  604  which is joined with good thermal contact with the electrical flat heating coil  601 .