Batch liquid purifier

Abstract: A batch liquid purifier (10) using a reservoir (11), an ozone generator (15), and a pumping system (20) is arranged for contacting the liquid with an ozone containing gas so that it is purified either during a direct outflow to a purified liquid chamber (12) or during a circulational flow back to a reservoir. The flow circuit can include a liquid gas separator (21) and venting of gas to atmosphere via an ozone concentration reducer (23). Pumping, valving, and controls can be accomplished in a variety of ways, as illustrated for systems.

Description: TECHNICAL FIELD This invention involves ozone purification of batches of liquid with equipment made small enough to operate on a countertop or in space available below a counter. BACKGROUND By this invention, I have reduced the size, complexity, and expense of equipment for purifying batches of liquid with ozone; and by carefully selecting and combining components, I have been able to make smaller scale ozone purification equipment operate conveniently and reliably for safely purifying liquid batches within reasonably short times. Equipment according to my invention can be operated on a residential countertop or in a small space under a counter, for example, to produce purified liquid batches less than 20 liters in size. US-A-3,382,980 relates to an ozone water treatment plant. It shows in Fig. 1 a water plant with two compartments 18, 19, wherein the first compartment 18 comprises an ozone generating unit 22. The second compartment 19 further comprises a mixing chamber 31, a contaminated water flow chamber 36, a storage chamber 37 for storing the purified water and an isolating chamber 38 which houses a float operated switch 39 arranged to automatically energize the water treatment plant when the storage chamber 37 falls below a predetermined level. US-A-3,726,404 discloses an apparatus for purifying drinking water wherein an ozonating unit comprises a contact tank containing a diffuser, an ozone generator and a storage tank removably mounted adjacent to the contact tank. Further a water pump is provided having its inlet connected to the contact tank and its outlet connected through a filter to the storage tank to pump the ozonated water from the contact tank to the storage tank. US-A-4,599,166 is directed to an ozone drinking water purification apparatus with a supply tank being installed in a household, e.g. on the roof of a dwelling lines 28-45; col. 2, lines 24-30). Further, US-A-4 599 166 discloses the use of a timer for determining the duration of the purification operation. SUMMARY OF THE INVENTION The purifier of this invention comprises a generator that makes an ozone-containing gas, a reservoir sized for holding in use less than 20 liters of liquid and including a vent, a gas pump arranged to pump in a purifying state an oxygen-containing gas into said generator and the ozone-generator-output gas containing ozone from said generator into contact with said liquid, a liquid pump arranged for operating in output state, where in said output state said liquid is pumped out from said chamber, means for preventing flow of liquid into said generator, a sensor arranged for sensing the concentration of ozone in said liquid and a control system responsive to said sensor for controlling the operation of said purifier in order to ensure that the liquid has been adequately purified. Further embodiments of the present invention are described in the depended claims 2-13 DRAWINGS All of the drawings are partially schematic diagrams of different preferred embodiments of my batch liquid purifier. Each embodiment includes an ozone generator, a reservoir of liquid to be purified, a pumping system for bringing ozone into contact with the liquid to be purified, a reducer for diminishing the concentration of any escaping ozone, and a controller to ensure that liquid purification occurs. The various embodiments of the drawings differ from each other in that: Figure 1 although not describing the invention, is included to assist in understanding the invention shows an in-line system for pumping liquid from a reservoir to a purified liquid container while contacting the liquid with ozone to ensure its purification. Figure 2 schematically shows a preferred alternative for a pumping system usable in the embodiments of FIGS. 1 and 3. DETAILED DESCRIPTION The preferred embodiments of the drawings have comparative advantages in features such as convenience, reliability, safety, cost, and compactness. Different embodiments, using different combinations of such features, may be preferred for different users with different desires. The embodiments will be explained in the order presented in the drawings, but this does not imply any similar order of importance. Also, some of the different features that are illustrated in the drawings can be interchanged among the various embodiments, and the drawings are arranged to illustrate the different features that can be combined, and not to delimit one combination of features from another. The reasons that the purifier embodiments can be varied so extensively include the many different uses for liquid purifiers and the correspondingly different considerations for expense, space requirements, and batch size. One important use is purifying water for drinking and cooking purposes. This can be done on or below a countertop with batches sized for coffeepots and hand-held pitchers. Different users will require different levels of sophistication in convenience and extent of automatic performance. Water can also be purified on a batch basis for small scale requirements in laboratories, offices, and industries. The liquid to be purified is not necessarily water, and my purifiers can be applied to purifying saline solution, for example. This could be desirable in an optometrist's office, for rinsing and storing contact lenses. The liquid purifier 10 of FIG. 1, although not describing the invention is included to assist in understanding the invention, purifies raw liquid as it flows from reservoir 11 to purified liquid container 12. A pumping system 20 directs the liquid flow from reservoir 11 to container 12 and contacts the liquid with an ozone containing gas from generator 15 so that the liquid is purified as the flow occurs. Reservoir 11 and container 12 are sized to hold less than 20 liters of liquid and can be made small enough to hold one coffee pot full of liquid, for example. Reservoir 11 can have a quickly releasable connection 13 that includes a check valve 14 for connecting and disconnecting reservoir 11 with liquid flow line 16 leading to pumping system 20. A gas flow line 17 leads from ozone generator 15, preferably via a check valve 18, to convey a gas and ozone mixture to pumping system 20. Besides conventional check valving, check valve 18 can be formed of a porous hydrophobic material that allows gas to pass through but prevents any liquid backflow from reaching generator 15. This is especially desirable when generator 15 is the preferred corona discharge generator that would be damaged by presence of any liquid. Suitable porous hydrophobic materials can include hydrophobic resin or plastic materials that are made porous to allow passage of gas, but block the passage of liquid. Porous inorganic materials may also be usable for this. The entire material does not need to be hydrophobic, so long as a hydrophobic material is arranged to serve as a liquid barrier combined with an otherwise porous material. These considerations also apply to other uses of porous hydrophobic materials in my purifiers, as explained below. Although ambient air is a simple and preferred input for generator 15, it is also possible to use dried air that has passed through a dryer to help keep moisture out of generator 15. Another possibility is supplying oxygen from a small container serving as the input to generator 15, which can produce more ozone from an oxygen supply than from an air supply. Pumping system 20 can take several forms, as explained more fully below. Generally, it draws liquid from reservoir 11 via liquid line 16 and contacts the liquid with ozone contained in a gas drawn via line 17 so that the ozone purifies the liquid before it reaches chamber 12. In the embodiment of FIG. 1, the gas and liquid output from pumping system 20 is directed to a gas and liquid separator 21. The gas drawn from generator 15 and combined with the liquid by pumping system 20 separates from the liquid in separator 21 and is vented to atmosphere. This preferably occurs through an ozone reducer 23 that reduces the concentration of ozone in any gas entering the atmosphere. Reducer 23 contains at least one of several materials that are available for reducing the ozone concentration or changing the ozone into ordinary oxygen so that raw ozone does not escape into the atmosphere. Even if raw ozone were to escape through vent 22, however, it should not present any health hazard in the small quantities used for operating system 10. There are several ways that gas and liquid separator 21 can operate. The liquid level is preferably controlled by a float valve, which has the advantage of keeping the liquid pressurized. Gravity can also be used to provide a liquid surface above which gas can rise. Another possibility is to arrange a porous hydrophobic element to form a barrier for liquid, while allowing gas to pass. The liquid and gas separation can occur separate from a liquid reservoir or purified liquid storage, or can be combined with these, as explained below. When reducer 23 is used and is filled with a catalytic or reactive material that reduces the ozone concentration or changes the ozone into oxygen, it is important that liquid not reach the material within reducer 23, because liquid would impair its action. Working against this is the fact that gas bubbles enter separator 21 and burst at the liquid surface there, creating spray droplets that can enter vent 22. Baffles are one possibility for keeping these spray droplets out of reducer 23, but baffles would not block liquid flow if the system were overturned. What I prefer, therefore, is a porous hydrophobic element 24 that allows gas, but not liquid, to enter reducer 23. From gas and liquid separator 21, liquid proceeds to purified liquid container 12. In doing so, purified liquid can flow past sensor 25, to detect the concentration of dissolved ozone in the liquid to verify that the liquid is adequately purified. Sensor 25 is preferably in communication with control system 30, which operates pumping system 20 and ozone generator 15. Control system 30 preferably includes a timer for timing each operation of system 10. An ozone sensor can also be arranged in this and other embodiments of my purifiers to ensure that purified liquid output does not contain more than a minimum of dissolved ozone. A timer can also be involved with control system 30 to ensure adequate de-ozonization of purified liquid output. Ozone sensors and timers for this purpose are preferably arranged in communication with the purified liquid storage or purified liquid output flow. The flow of purified liquid into chamber 12 can also pass through filter 26, which can contain activated carbon or a catalyst that greatly reduces the concentration of dissolved ozone remaining in the purified liquid. This can be advantageous in situations requiring that little or no dissolved ozone remain in the liquid that is output from chamber 12. Other ways of ensuring this are to let the purified liquid stand for a few minutes in chamber 12 before using it, to aerate the purified liquid before using it, or to subject the purified liquid to ultraviolet light. By whatever method is used, the dissolved ozone concentration should be reduced before the purified liquid is output for use or consumption. For most purposes, dissolved ozone is acceptable in the purified liquid; and no health hazard has yet been identified with directly consuming water containing dissolved ozone at levels found in system 10. Control system 30 also preferably includes a switch that initiates operation of system 10. This can run pumping system 20 and ozone generator 15 for long enough to empty reservoir 11 and transfer purified liquid to chamber 12. Sensor 25 can verify from the presence of dissolved ozone in the passing liquid that ozone generator 15 is operating and delivering ozone to the moving liquid. If sensor 25 does not detect ozone in the liquid, a warning or indicator light could be illuminated to inform the operator, or control system 30 could shut down pumping system 20 and generator 15. An alternative pumping systems 20, suitable for use in system 10 of FIG. 1 and system 60 of Fig. 3, is shown in FIG. 2. The flow rates of liquid and gas through any pumping system used with my liquid purifier are preferably adjusted by sizing the liquid and gas conduits relative to the pumping rate and the force causing flow to occur. This eliminates the expense of detecting and metering flow rates to ensure adequate contact of liquid with ozone. The time that liquid and ozone are in contact with each other is also a factor in the purification process, since purification is a function of both the extent and the duration of ozone contact with liquid. Thus, pumping systems and liquid and gas flow lines should be selected to ensure proper flow rates of liquid and gas and adequate contact times between liquid and the ozone contained in the gas. Pump 33, of the embodiment of FIG. 2, is a gas pump that forces the ozone containing gas through line 17 into chamber 34 from which a bubble line 35 extends. Gas bubbles rising in chamber 34 not only contact liquid present there, but also pump the liquid through bubble line 35 as the bubbles rise. This moves the gas and liquid mixture downstream toward gas and liquid separator 21 (not shown in FIG. 2). Gas pump 33 is preferably arranged upstream of generator 15 so that it can force gas through generator 15, which outputs a mixture of gas and ozone. Pump 33 can also be arranged downstream of ozone generator 15, except that an ozone environment is too corrosive and problematic for most pumps to handle. According to the present invention two pumps are used in system 60 of FIG. 3. A gas pump 51 pumps an oxygen-containing gas such as ambient air, dried air, or oxygen into ozone generator 15 so that an output gas containing ozone is bubbled through diffuser 52 into the liquid in reservoir 36. The bubbles contact the liquid with ozone and accomplish its purification within reservoir 36. Diffuser 52 is porous and allows gas to flow through, preferably in a way that divides the gas flow into a multitude of bubbles. Although air stones and other materials are available for diffuser 52, I prefer a porous element made from or including a hydrophobic material that allows the ozone containing gas to flow through, but resists any flow of liquid in the opposite direction. Since a multitude of small bubbles are desirable for liquid-gas contact, and since a bubble diffuser of a given pore size produces smaller bubbles if the surface tension of the diffuser material is increased, there may be advantages in using separate materials to provide the porous hydrophobic liquid barrier and a porous bubble diffuser. For example, a hydrophilic porous material or coating on top of a porous hydrophobic material can exploit the advantages of both materials. There are also many different ways of combining porous hydrophobic liquid barriers and other porous materials producing fine diffused bubbles. By including a porous hydrophobic material, diffuser 52 can then serve as a liquid barrier, ensuring that no liquid travels back to generator 15. This is important because the preferred form of generator 15 is a corona discharge device that would be damaged if liquid were to enter it. Trap 37, is preferred for adding liquid to reservoir 36. Another way to ensure that liquid does not enter generator 15 is by directing the output from generator 15 to a level higher than the liquid level within the system so that gravity prevents liquid from flowing through the elevated passageway to generator 15. This would require that the system not be turned over while it contains liquid. A check valve can also be arranged in output line 17 from generator 15, as shown in FIG. 1, to help protect generator 15 from liquid. Besides a conventional check valve, the check valve can be formed of a porous hydrophobic material that allows gas to pass through but prevents any liquid backflow from reaching generator 15. Reservoir 36 also serves as a gas and liquid separator, allowing gas to flow through vent 22 and ozone reducer 23, which is preferably protected from liquid by porous hydrophobic element 24. Sensor 25 can detect the presence of dissolved ozone in the liquid in reservoir 36 so that control system 30 can operate the purification cycle long enough to ensure that the liquid is adequately purified. Liquid pump 53 outputs purified liquid from reservoir 36, preferably in response to a demand switch 54 arranged near the outlet and communicating with control system 30. The purified liquid outflow through pump 53 can also pass through filter 56 to remove any precipitated impurities and to reduce the concentration of any ozone still dissolved in the purified liquid, before the liquid is output. system 60 can be operated, by actuation of switch 58, to purify a liquid batch in reservoir 36 and then in response to switch 54 to flow the purified liquid to the outlet on demand. Reservoir 36 can be refilled on a batch basis preferably via trap 37 or from a pressurized supply line via a valve that is not shown in FIG. 3. It can also have a drain 57 and can be arranged under a countertop or in a basement below a kitchen, for example, since pump 53 allows it to deliver the outflow to a higher elevation.

Claims: A batch operation purifier, said purifier comprising: a generator (15) that makes an ozone-containing gas; a reservoir (36) sized for holding in use less than 20 liters of liquid and including a vent (22); a gas pump (51) arranged to pump in a purifying state an oxygen-containing gas into said generator (15) and the ozone-generator-output gas containing ozone from said generator into contact with said liquid; a liquid pump (53) arranged for operating in output state, where in said output state said liquid is pumped out from said reservoir (36); means for preventing flow of liquid into said generator; a sensor (25) arranged for sensing the concentration of ozone in said liquid and a control system (30) responsive to said sensor (25) for controlling the operation of said purifier in order to ensure that the liquid has been adequately purified. The purifier of claim 1 wherein said flow preventing means comprises a porous hydrophobic material in output line (17) from generator (15). The purifier of claim 1 and 2 further comprising a diffuser (52) in the reservoir (36) to bubble through in the purifying state the output gas containing ozone. The purifier of claim 1 and 3 wherein said flow preventing means comprises a diffuser (52) made from or including a porous hydrophobic material. The purifier of claim 1 wherein said flow preventing means comprises means for directing in use the output gas line (17) from generator (1 5) to a level higher than the liquid level within the system. The purifier of claim 1 wherein said flow preventing means comprises a check valve arranged in output line (17) from generator (15). The purifier of claim 1 including a filter arranged downstream of said reservoir when said pumping system is arranged for operating in said output state. The purifier of claim 1 wherein said system (30) is arranged for operating said gas pump (51) in said purifying state and an output switch arranged for operating said liquid pump (53) in said output state. The purifier of claim 1 including means (23) for reducing the concentration of any ozone escaping into the atmosphere. The purifier of claim 1 including means (23) for reducing the concentration of any ozone escaping from said vent (22), and a porous element (24) including a hydrophobic material arranged for preventing liquid from entering said vent (22). The purifier of claim 1 including means for reducing the concentration of ozone dissolved in liquid before pumping said liquid out from said purifier. The purifier of claim 1 including means for disconnecting said reservoir (36) from a liquid passageway connected to said pumping system. The purifier of claim 1 including a demand switch (54) arranged near the outlet and communicating with control system (30) for outputting purified liquid from reservoir (36).

Inventors: BURRIS WILLIAM ALAN, BURRIS, WILLIAM ALAN
Applicants: BURRIS WILLIAM ALAN, BURRIS, WILLIAM ALAN
Application year: 1992
Main classification: A61L2
IPC codes: A61L2, C02F1, B01D19