MXPA96004711A - Portable apparatus for purification of a - Google Patents

Abstract

A water purification apparatus (10) is described, which can be placed on an existing dispenser (158), which has a valve control element (154) that can be placed in the water enclosure of the dispenser, to control the release of the water. Purified water from the appliance to the distributor. A water supply tank (26) receives the water supply (52) to maintain the water level in the boiler (60) of the appliance above the heating element. The control tank includes a partition separating a main tank (68) from a defoaming control chamber (70), into which antifoam agent can be added. The water leaving the tank enters the boiler, where it evaporates and the vapors enter a condenser (114), where the steam condenses into water. The condenser (114) is developed in a certain number of convolutions around a central opening (115) and has external heat exchange fins (116). An end cap assembly (118, 126, 130, 134, 136) closes the central opening (124) except for a small portion through which air is sucked in by means of a fan, so that substantially all the air It flows on the fins. The boiler is a cylindrical container having a peripheral lip (96) around an open end, on which a lid (94) having a steam outlet pipe (100) is placed. The lid is secured in a sealing relationship with the lip by a coil spring (104) forced by a bar (106) having fasteners (108) which secure the peripheral lip (9).

Description

PORTABLE APPARATUS FOR WATER PURIFICATION BACKGROUND OF THE INVENTION This invention relates, in general, to a portable water purifier for purifying and storing potable water and, more particularly, to a purifier that can be placed in an existing water cooling and distribution unit. conventional. Interest in the purity of drinking water and its taste have driven alternative sources of supply, in addition to that provided by the tap water. This aspect has been driven by widespread reports on water pollution and by the fact that tap water often contains large amounts of chemical agents for the treatment of water, minerals and other materials. One attempt to address this problem is the increased use of bottled water. The sale of bottled water, which has increased substantially in recent years, generally consists of a quantity from a single ration to a gallon, sold in retail establishments, and larger containers, eg, 5 gallon containers, They are sold for use with water coolers. Bottled cold water dispensers are extremely popular for both residential and commercial use, because they can REF: 23182 distribute potable, cold water in bottles with a capacity of generally three to five gallons, without the need for pipeline installations. However, this type of packaged water is expensive and the change and storage of large, heavy and bulky bottles is onerous. Several problems related to the quality of bottled waters have also been discovered and published in recent years. Bottled waters can be easily contaminated by airborne bacteria and viruses during the distribution operation, due to the introduction of ambient air that is sucked into the bottle as the water is distributed. In addition, stagnant storage of bottled water allows bacteria to grow without hindrance. The discoveries of dangerous chemical agents and extremely high levels of bacteria in bottled waters has led many to the conclusion that bottled water may not be purer, or sometimes less pure, than ordinary tap water. These problems with tap water and bottled water have revealed the need and desire for water treatment at the point of use. There are several treatment alternatives at the point of use for tap water and bottled water, and they are well known in the art. One of these alternatives is the use of charcoal filtration, which uses activated charcoal to remove impurities, which consist mainly of of organic compounds, and improve the taste of water. Carbon filters, however, are generally ineffective in eliminating most inorganic compounds, such as lead and arsenic. Another alternative known in the art is the use of reverse osmosis to treat water. The reverse osmosis units use a pre-filter of the sediment. These units, however, have a tendency to become clogged by high levels of hardness minerals and therefore are not viable for some geographic locations. Other problems with reverse osmosis include the expense of approximately 80% of the feedwater, the high cost of replacing the membranes and the requirement of pressurized water supply lines and water drainage lines, which eliminates the ability to be portable Another alternative method for water treatment at the point of use is distillation. The distillation devices purify the water by boiling the water to generate steam and then condense the vapor to form water free of these contaminants. Contaminants that have a vaporization temperature higher than that of water remain in the boiler; while solvents, which have a boiling point lower than that of water, can be separated from the vapor by ventilating them before condensation. The distillation process is more effective to eliminate impurities than reverse osmosis and does not present the problem of waste of Water. Distillation devices can be portable, without the need for pressurized power lines and drain lines; or non-portable, requiring power lines to supply the water. Distillation alone, however, is relatively ineffective in eliminating volatile chemical agents, such as benzene and chlorine. Existing portable distillers and most non-portable devices can not adequately address the problem of scaling and cleaning the boiler, such as the portable distillation device shown in US Patent No .4,342,623, which has no provision to prevent the accumulation of scale. Other portable distillation devices, of the prior art, have a mobile boiler, but which requires a partial disassembly of the unit to remove the boiler. Additionally, most known distillation units include a floating valve within the boiler, such as in U.S. Patent No. 4,943,353, and therefore it is exposed to the accumulation of scale. When excessive deposition of scale occurs, a malfunction of the float valve may occur, which may cause overheating and system malfunction. Other distillation units, such as that described in US Patent No. 5,178,734, may have an external solenoid valve controlled by level indicators within the boiler. The indicators are exposed, therefore, to the accumulation of incrustations. The distillation units in the prior art are of the type where the water is distilled and captured for later use, as illustrated in U.S. Patent No. 4,342,623; of the type where non-cold water can be distributed, as illustrated in U.S. Patent No. 4,622,102; or of the type where the distillation unit is coupled with refrigeration, as illustrated in U.S. Patent No. 3,055,810. As mentioned earlier, bottled water dispensing devices are extremely popular. Accordingly, it is advantageous to replace the water bottles in these containers with a less expensive source of purer water, such as an efficient distillation unit. In US Patent No. 5,281,309, assigned to the common assignee of the present invention, a water purification apparatus is described which is mounted within a housing adapted to be placed on a conventional water cooler / distributor apparatus. The apparatus includes a valve control element that extends from the housing and that can be placed within the water reservoir of the dispensing apparatus to control the release of purified water from the device to the tank. To provide a compact housing for the water purification apparatus, a boiler having a small cross-section was provided in order to provide a high-energy heating element in the boiler; the length of the boiler was extended to prevent the water in the boiler from splashing or rapidly vaporizing upwards towards the condenser coil, a condition known as "carry-over"; The boiler described in the aforementioned patent application was elongated. Additionally, the water level inside the boiler was controlled by means of the water level in the water feed tank, which is located in an upper portion of the appliance, so that the height of the boiler had to be large enough to prevent water from flowing into the boiler or splashing into the condenser. In the co-pending US Patent Application No. 08 / 136,449, filed on October 14, 1983, also assigned to the joint assignee of the present application, a baffle was placed above the heating element, in the boiler, to prevent the transfer , and a separate water level control tank was placed between the water feed tank and the boiler so that the water level in the boiler remained independent of the water level in the water feed tank. The steam that forms in the boiler flows towards the • - condenser, where it cools and condenses in water free of contaminants. The condenser is generally a helical coil having a certain number of convolutions and having external fins to provide a large heat transfer surface area to receive heat from the coils by conduction. Cooling air is forced onto the fins to receive energy from the fins by convection. In the prior art water purification apparatus, the cooling air flow has been through the center of the helical coil. The air, therefore, comes into contact with the portions of the fins that border only along the central path. To increase the efficiency of the heat transfer a balloon, or a similar device, has been mounted in the center of the coil, to put a frictional resistance in the central portions, so that the air is directed between the outside of the balloon and fins. However, even with this construction only a small portion of the air flows through the entire surface of the fins. If the air could be directed completely over the fins, the coil could be shortened substantially. The present invention is directed to, and provides a solution to, this problem. Another problem with the prior art, to which the present invention is directed, is the manner of securely mounting the boiler within the housing housing of the apparatus. In general, a connecting element, such as a pin or a rod, extends through at least one end of the boiler, to fix the boiler to a portion of the housing. Not only does this type of construction require a hermetic seal around the connection element, which functions properly at elevated temperatures, but also because a portion of the connection element, which is inside the boiler, is subject to the action corrosive of the heated water and steam and the accumulation of scale. Under these circumstances, disassembly of the boiler, when required, may present difficulties. « COMPENDIUM OF THE INVENTION As a consequence, it is a main object of the present invention to provide a purification apparatus that is compact, yet efficient and highly effective, the apparatus must be easily mountable on a water chiller dispenser unit, for purification at the point of use of drinking water. It is another object of the present invention to provide a water distillation and purification apparatus having a compact, highly efficient condenser, wherein the cooling air is directed so as to flow over substantially all surfaces of the fins of the condensing coil. It is a further object of the present invention to provide a water distillation and purification apparatus that has a boiler mounted in the housing of the apparatus without connection means that penetrate the interior of the boiler, so as to eliminate the problems of hermetic and corrosion that would occur with such a construction. Accordingly, the present invention provides a water distillation and purification apparatus having a coil condenser with a certain number of convolutions around a central opening, including outer fins where cooling air is forced upwards, through the center of the coil and prevented from exiting above the coil, so that all the cooling air is directed to flow laterally on the fins, whereby the cooling capacity of the coil is substantially increased and the length of the coil is substantially reduced. A fan is mounted below the coil to force air upwards, the size of the fan and therefore the noise created by it can be substantially reduced by means of the more efficient flow of air provided by the present invention. To prevent air from coming out from above the coil an end cap assembly is provided, which closes the central ring or opening inside the coil, except at the air inlet and forces the air to take a path that results in the air flows over the fins, which consequently transfers the heat from the coil to the air in a way efficient. Another aspect of the present invention provides a water distillation and purification apparatus having a boiler in the form of a cylindrical can having an end closed and having a peripheral lip placed around an open opposite end, a lid is placed over the open end and forced, tightly, until a sealing relationship with the lip is achieved. The cap includes a steam outlet tube and a spiral spring lf 'is placed around the tube and forced to remain against the lid by a bar which is connected to the lip by means of fasteners, so that the bar it is forced against the insulation placed on the lid and thereby forces the lid tight against the periphery of the end open.

BRIEF DESCRIPTION OF THE FIGURES The particular characteristics and advantages of the invention, as well as other objectives, will become apparent from the following description, taken in connection with the 20 figures that accompany it, in which: Figure 1 is a view front view, partially developed, of a water distillation and purification apparatus constructed in accordance with the present invention; Figure 2 is an end view, in elevation, of the - - apparatus illustrated in Figure 1, with the end panel removed; Figure 3 is a schematic view of the water distillation and purification apparatus of the present invention; Figure 4 is a schematic view of the water level control tank and a defoaming chamber of the apparatus; Figure 5 is a perspective, developed view of the condenser portion of the apparatus illustrated in Figure 1; Figure 6 is an elevational view, partially in cross section and developed, of the boiler illustrated in Figure 1; and Figure 7 is a fragmentary view, in elevation, with the parts thereof separated and in section illustrating the assembly of the apparatus of Figure 1 on a water cooler and distributor.

DESCRIPTION OF THE PREFERRED MODALITY Referring to the Figures, a water distillation and purification device, 10 constructed in accordance with the principles of the present invention, comprises a housing having a substantially rectangular configuration including a base 14, having a floor 15 and a plurality of vertical walls 16, 18, 20, 22, respectively, forming a portion of the walls front and rear and the end walls of the housing. A panel 21 is connected to the side portions of the wall 20 to have access to the housing. Mounted on the base 14 is a distillate tank, or distilled water 24, the tank has a height of about half the vertical walls. A water feed tank, 26, is mounted on top of the distillation tank 24 and has its upper part substantially coplanar with the cover 28, coupled on the upper edges of the vertical walls 16, 18, 20, 22. Tanks 24 and 26 are preferably formed from a transparent or translucent plastic material, such as polyvinyl chloride or polypropylene and have walls that rest against the wall 22, while the other walls are adjacent to the front and rear walls 16 and 18, respectively. The water feed tank 26, preferably has an opening 30 in its upper part, normally closed by a filler cap 31, so that the tank can be filled with water in a batch mode normally through the opening. Alternatively, the apparatus can be made automatic by connecting it to the pipe system at the location where it is used, the pipe system is connected to the pipe extending through the opening 32 in the end wall 20 extending through the other wall from end 22 and towards the water feed tank 26.

Mounted within the water supply tank 26, at least for those units that are filled automatically, is a float 34, the float is part of a floating valve assembly that includes an arm 36 extending from the float to a float. valve member 38, connected through pipe 40 extending outwardly from the water supply tank, through opening 32, to connect with the pipe system. Accordingly, when the level of the water within the tank 26 reaches a desired, predetermined amount, the valve member 38 is actuated to cut the flow of water from the pipe 40 to the tank. As best illustrated in Figure 2, the water supply tank 26 communicates by means of an outlet fitting 42, adjacent to the bottom thereof, and extends through the wall 22 to be connected with one end. of the pipe 44, the other end of the pipe 44 is connected to an outlet fitting 46. Preferably, a preconditioning filter, 48, which softens the water, may have an inlet connected to the fitting 46 and has an outlet that is connected to an intake fitting 50, of a small housing of substantially rectangular shape, 52, comprising a water level control tank, better illustrated in Figure 4. Accessory 50 includes a valve element 54, controlled by a float 56 which is connected to the valve 54 by means of an arm or rod 58, so that cut the water flow from the water supply tank 26, through the tube 44, when the water inside the tank 52 is at a desired level. This water level is equivalent to the water level in the boiler 60, the boiler is connected to the water level control tank by means of an outlet pipe 62, which extends between the control tank 52 and the boiler 60, as illustrated in Figure 2. A flow restriction device, 64, within the tube 56, provides resistance to prevent hot water from flowing back from the boiler to the level control tank. The water level control tank acts to control the water level inside the boiler. While the valve 54 remains open, water flows from the water supply tank 26 to the boiler 60 because the water supply tank 26 is at a greater height than the boiler 60 and the water control tank 52 An anti-foaming agent, such as the antifoam compound "A", Dow Corning, food-grade silicon antifoam and similar products, can be applied to the water before the water enters the boiler 60, so that heating and drying is prevented. Subsequent breaking of the agent in the boiler, by diluting the agent without requiring an expensive quantification system. To this end, the water level control tank can be divided by a wall 66, which divides the control tank into a main tank 68 and an antifoam chamber 70, the wall 66 has an upper end that terminates below the top 71 of the tank 52 and the stem 58, away from the float 56. A vertical tube 72 has one end placed inside the chamber 70 and another end extending through the wall of division 66, in a location separated above the water level maintained by the float 56 and the valve 54. Additionally, the rod 58 of the float valve assembly, which is preferably a flat rod, is twisted 90 ° so that pivot at one end, in the valve housing 75 and can be easily bent at its other end to join the float 56, has a configuration that includes an arcuately bent portion 74, so that it can be projected from the float 56, in one end, below the wall 66 and extending over the wall 66, towards the other end, where it is pivoted in the valve housing 75 to open and close the valve 54, illustrated in the closed position in Figure 4. Adjacent to the valve 54, the rod 58 has a neck portion 76 that extends downward towards the chamber, so that water entering through the accessory inlet 50, when the valve is open, will come into contact with neck portion 76 and will fall to the lowest point 78, below the neck, towards chamber 70. Top 71, of tank 52, is open at least above the antifoam chamber 70, so that the anti-foam agent can be emptied periodically to chamber 70. Water drops from valve 54 to chamber 70, mixes with antifoaming agent, which is a gel lighter than water, and diluted mixture rises through tube 72, from the bottom from the chamber 70, to the level control tank, 68, to subsequently flow through the outlet orifice 62, to the boiler 60. Accordingly, the water entering the boiler has the defoaming agent suitably diluted, up to about 1 to 5 parts per million, to avoid frothing inside the boiler without breaking, of course, the antifoaming agent becomes more concentrated in the boiler as the water boils. The boiler 60 is constructed of a non-corrosive material, such as stainless steel, in the form of a cylindrical can, closed at the bottom and covered by an insulation in the form of a hollow, cylindrical sleeve, 80. The length of the boiler is such that the upper end is below the water supply tank 26, so that the housing 12 can be of compact size. As illustrated in Figure 3, the water level inside the boiler is controlled by the water level inside the tank of the water level control tank 52, because the boiler communicates with the tank of the water tank. control 68, by means of the tube 62 and the reducing valve 64. Accordingly, when there is sufficient water in the water supply tank 26, the water level in the water tank control of the level 52 and in the boiler 60 is always located above the upper part of the heating coil 82, in the boiler, so that the boiler will not dry heat. This is ensured by mounting the water feed tank 26 to a level higher than the control tank 52 within the housing 12 and placing the float 56 so that the level of the water within the control tank is above the water level element. heating 82, while cutting the flow when the water in the boiler is a few inches above the heating element. The boiler is equipped with a drainage line 84 which is connected to a manually operated valve element, 86, on the front of the apparatus, so that the boiler can be drained periodically to avoid excessive levels in the concentration of contaminants in the boiler. the boiler A drain timer 88, which activates a light 90 on the front of the apparatus, notifies the user that the boiler should be drained, a reset disk 92 that resets the system. The upper end of the boiler has a disc-shaped cover or cover 94, which can be removed, sealed in a sealed manner to the boiler in a unique manner. To this end, the upper edge of the boiler has a lip 96, arcuately molded, positioned outwardly, as illustrated in Figure 6. A ring-shaped silicone packer, 98, is positioned around the periphery of the cover or cover 94 and the assembly rests on the lip 96. The The lid 94 has a central opening into which the outlet pipe 100, of the boiler, is received so that steam from the boiler can exit through the tube 100. A foam insulation 102 is placed on the upper part of the boiler. the lid 94 and has a central opening through which the tube 100 can pass, a helical spring, 104, is placed in the insulation opening, around the tube 100. Placed on the insulation is a bar, 106, which rests on the upper surface of the spring 104 and a pair of hooks 108, S-shaped, are received within the openings in the bar 106, to hold the bar at one end and the other ends are received at the lower side of the lip 96, for pulling the bar tightly against the spring 104 and forcing the spring against the top of the lid 94, to securely secure the lid in a sealing relationship with the top of the boiler. A clamping flange, 110, surrounds the boiler and passes through an opening 112, in the wall 20, to firmly secure the boiler in place, against the floor 15, to prevent movement of the boiler. With this type of construction no connection elements are required to enter the boiler, so that the sealing problems with respect to the assembly of the boiler are avoided. The outlet pipe of the boiler 100 extends upwards from the boiler and is connected to the intake end of a condensing coil 114, wound in a a number of convolutions, similar to a helix, but in a circular shape, and having a central opening 115, as best illustrated in Figure 5. As is conventional, the condensing coil 114 has a multiplicity of transfer fins of heat, 116, placed around the entire outer surface; the fins are separated from the walls 16, 18, 20, 22. A floor, 118, is secured to the walls 16, 18, 20, 22, above the boiler and below the condenser 114. A fan housing 120, which includes a fan 122, is secured to the bottom surface of the floor 118; the floor has an opening 124 through which air can be supplied, by means of the fan, upwards, on the fins 116 and the condenser 114. Placed on the upper surface of the floor 118, there is a foam pad 126, which it has an opening 128, substantially in the shape of the condensing coils, and a vertical integral wall, 130, around the opening and of the same peripheral configuration. The wall 130 has an upper edge or surface, 132, which varies in elevation according to the lowermost convolution of the condensing coil, so that the lowermost helix can rest on the upper edge 132 of the wall 130, as shown in FIG. better illustrated in Figures 2 and 5. Placed on the upper convolution of the condensing coil, 114, is the surface of a wall 134 extending downward, similar to the wall 130, the wall 134 is formed over, and extends downwardly of, a foam ceiling 136 which abuts, and is held fixed by the cover 28. The roof element 136 is positioned in the central area, above the opening 116 of the convolutions of the condenser coil 114. Accordingly, the walls 132, 134, and the roof member 136 act as a seal, to direct all the air coming from the fan around the fins 116, from the central opening 115, laterally outwardly. , towards the walls 16, 18, 20, 22, where the air exits through various openings in the housing, including the openings 137, in the cover 28. This produces a large cooling capacity and allows "the length of the coil In addition, the size of the fan and the noise created by the fan can also be greatly reduced, therefore, as the steam also flows through the serpentines it is cooled down. and condensed in distilled water. The distilled water leaving the condenser flows out of the apparatus, through a conduit 138, to an external filter 140 and then back, through the pipe 142, through the wall 120, and into the water tank distilled 24. The filter 140 preferably has a mixture of activated carbon, calcium carbonate and magnesium, which slowly dissolve to improve the taste of the water and raise its pH value. Connected to, and communicating with, the tank of distilled 24 is the pipe 144, illustrated schematically in Figure 3, which extends externally to the distillate tank and which is connected to an outlet fitting 146, on the base 14. A pipe 148 is connected to the fitting 146 , at one end, and at its other end is connected to a float control valve element, 150. The valve member 150 is part of an assembly that includes an arm 152, which connects a float 154 to the valve element. . When the float is raised to a predetermined position, the valve closes and the flow of water from the distillate tank 24 is interrupted through the tubes 144 and 146. The valve 150, the arm 152 and the float 154 are located placed inside a container or crankcase 156, which is connected, so that it can be removed, to the floor 15 and extending downwards, from the apparatus, below the base 14. Consequently, as illustrated in Figure 7, the water purification apparatus 10 can be placed on a conventional bottled water cooling and distribution unit, 158, when the water bottle is removed and the crankcase 156 is received within the upper ring of the booth, 160, of the distribution unit 158, with the float 154 placed inside the water tank or enclosure 162, of the distribution unit 158. The water level, inside the tank 162, of the chiller unit and of the distribution 160, therefore affects the operation of the valve 150 and the flow of water from the distillate tank 24, towards the chiller and distribution unit 158. A low water level switch 164, controlled by a float element 166 in the water supply tank 26, can be included, so as to prevent the boiler from running out of water when the water level inside the tank 26 cause the float to activate the switch 164. Similarly, a high water level switch 168 may be included in the distillate tank 24, controlled by means of a float 160, to interrupt the operation of the unit when the distillate tank 24 is full. Numerous alterations of the structure described here will suggest themselves to those trained in the art. However, it should be understood that the present disclosure relates to the preferred embodiment of the invention, which is for purposes of illustration only and should not be taken as a limitation of the invention. All these modifications do not depart from the spirit of the invention and are intended to be included within the scope of the appended claims. It is noted that, in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it refers. Having described the invention as above, the content of the following is claimed as property.

Claims (8)

- - CLAIMS

1. A water purification apparatus, characterized in that it comprises a housing, which includes a plurality of vertically extending walls; a water feed tank, to receive the water to be purified; a distillate tank, to store the purified water to be distributed selectively; a vertical boiler that has a heating element placed inside it, to boil the water that is received from the water supply tank; a condenser mounted above the boiler, to receive steam from the boiler and to condense this steam to form distilled water, where the condenser comprises a twisted tube, around a central opening, in the form of a coil having a plurality of convolutions, one above the other, a multiplicity of fins placed around this tube, spaced from the walls, to provide a relatively large surface area for the transfer of heat from the tube; a fan mounted below the condenser to suck cooling air into the opening; sealing means, including wall elements, placed resting on the fins of the convolutions, the uppermost and the lowermost, to substantially eliminate the flow of air upwards and downwards and consequently force the cooling air to make it flow from the opening laterally on the fins - - towards the walls that extend vertically and outwards from the housing; and means that communicate the condenser with the distillate tank, to supply distilled water to the distillate tank.

2. The water purification apparatus, according to claim 1, characterized in that the sealing means include a plate, placed intermediate the boiler and the condenser, having an opening, where the fan is secured to the plate and supplies air through the opening; and a pad, mounted on the plate, where this pad has wall elements that extend upwards.

3. The water purification apparatus, according to claim 1, characterized in that the sealing means include a pad, placed above the condenser, which closes the central opening, and wall elements extending downward, from the pad .

4. The water purification apparatus, according to claim 3, characterized in that the sealing means further include a plate, positioned intermediate the boiler and the condenser, having an opening, where the fan is secured to the plate and supplies air through the opening; and a pad bottom mounted on the plate where this lower pad has wall elements that extend upwards.

5. The water purification apparatus, according to claim 1, characterized in that the boiler comprises a cylindrical container, substantially cup-shaped, having a closed lower end and an open upper part including a peripheral lip; means for communicating the container with the water supply tank; a disk-shaped lid that can be communicated on top of this, the lid has an outlet tube that connects the boiler with the condenser; an airtight seal placed around the periphery of the lid, which is placed on the lid; a spring 'placed around the outlet tube and resting against the lid; and securing means for forcing the spring against the lid and forcefully coupling the sealing with the lip.

6. The water purification apparatus, according to claim 5, characterized in that the securing means comprise a bar placed above and leaning against the spring; and means connected to the bar and lip to draw the bar towards the lid, to compress the spring.

7. A water purification apparatus that has a tank of water supply to receive the water to be purified; a boiler to receive water from the water supply tank; a condenser to receive steam from the boiler and to condense the steam to form distilled water; and a distillate tank for receiving the distilled water from the condenser and storing the distilled water for selective distribution, characterized in that the boiler comprises a cylindrical, substantially cup-shaped container having a closed bottom end and an open top , which includes a peripheral lip; means for communicating the container with the water supply tank; a disk-shaped lid that can be placed on top, where the lid has an outlet tube that connects the boiler with the condenser; an airtight seal placed around the periphery of the lid placed on the lip; a spring placed around the outlet tube and resting against the lid; and securing means for forcing the spring against the lid to forcibly couple the seal with the lip.

8. The water purification apparatus, according to claim 7, characterized in that the securing means comprise a bar placed at the top and resting on the spring; and means connected to the bar and the lip to draw the bar towards the lid to compress the spring. SUMMARY OF THE INVENTION A water purification apparatus (10) is described, which can be placed on an existing dispenser (158), which has a valve control element (154) that can be placed in the water enclosure of the dispenser, to control the release of the water. Purified water from the appliance to the distributor. A water supply tank (26) receives the water supply that is fed to a water level control tank (52), to maintain the water level in the boiler (60) of the appliance above the heating element. The control tank includes a partition separating a main tank (68) from a defoaming control chamber (70), into which antifoam agent can be added. The water leaving the tank enters the boiler, where it evaporates and the vapors enter a condenser (114), where the steam condenses into water. The condenser (114) is wound in a number of convolutions around a central opening (115) and has external heat exchange fins (116). An end cap assembly (118, 126, 130, 134, 136) closes the central opening (124) except for a small portion through which air is sucked in by means of a fan, so that substantially all the air It flows on the fins. The boiler is a cylindrical container having a peripheral lip (96) around an open end, on which a lid (94) having a tube of - - steam outlet (100). The lid is secured in a sealing relationship with the lip by a coil spring (104) forced by a bar (106) having fasteners (108) which secure the peripheral lip (96).