Abstract:
An apparatus for oxygenating a liquid, including a liquid pump, supply piping having an inlet connected to the pump and an outlet, first and second injectors and a chamber. The first injector has a liquid inlet forming a nozzle, a liquid outlet and an oxygen inlet, the first injector oxygen inlet intermediate the first injector liquid inlet and outlet, the supply piping outlet connected to the first injector liquid inlet. The second injector has a liquid inlet forming a nozzle, a liquid outlet and an oxygen inlet, the second injector oxygen inlet intermediate the second injector liquid inlet and outlet, the first injector liquid outlet in communication with the second injector liquid inlet, whereby liquid flows through the first and second injectors in series, each of the first and second injector oxygen inlets provided with a source of oxygen gas. The chamber has a liquid inlet and a liquid outlet, the second injector liquid outlet in communication with the chamber liquid inlet, whereby liquid flows through the second injector and the chamber in series. A process for enriching a liquid with oxygen is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an apparatus for oxygenating a liquid, i.e., preparing the liquid in solution with oxygen, a method for oxygenating the liquid, and applications of liquids oxygenated by the inventive apparatus and method. The liquid to be oxygenated may be water, for example, or any of a number of other liquids. 
     It is known that various types of liquids are oxygenated to achieve various results. For example, consumption of an oxygen enriched beverage has a favorable effect on well-being and physical performance, for it provides oxygen to the bloodstream through the stomach lining or intestinal wall. In one case, eight test subjects of various ages and differing sex had their blood oxygen contents and their pulse rates determined. Each subject then drank between ½ and ¾ liters of highly oxygenated water. A short period after ingestion of the enriched water, evidence of a pulmonary function bypass was observed through an average blood oxygen level increase of about 30%, and the effect of a concomitant cardiac relief was observed through an average pulse rate reduction of about 10%. Further, the added oxygen tends to reduce the tartness of any carbonation and does not impart any taste to the resulting liquid. 
     As a further example, aerobic processes advantageously employ oxygen-containing liquids. As used throughout the specification and the claims, reference to an “aerobic” process generally includes all chemical and microbiological processes in which a chemical or microbiological process is carried out or is promoted in a liquid medium in the presence of oxygen. Suitable aerobic processes in which an oxygenated liquid can be advantageously employed include, for example, processes in which heretofore water has been aerated such as by bubbling air thereinto, and also in situ or ex situ bioremediation of contaminated (e.g., with petroleum products) or oxygen-depleted bodies of water; wastewater, sludge and animal waste treatment, both by fixed film and by suspended growth methods; rehabilitation of atrophying lakes; biological oxygen demand (BOD) reduction techniques; fresh water aquaculture (e.g., fish farming); salt water aquaculture (e.g., shrimp farming); hydroponic agriculture; odor suppression barriers for anaerobic processes; and insolubilization of dissolved contaminates (e.g., iron, and manganese ions) for removal by filtration or sedimentation. 
     It is also known that some fermentation processes, i.e., processes which involve fermenting a fermentation liquor, commonly employed in drug production or food processing by microorganisms, benefit from the fermentation liquor being comprised of an oxygenated liquid. 
     It is also known that numerous types of therapeutic processes can benefit from the use of oxygenated liquids. “Therapeutic” processes, as used throughout the specification and the claims, involve the oxygenation of the body or its parts by treatment with an agent in a liquid vehicle containing dissolved oxygen. Suitable therapeutic processes in which an oxygenated liquid can be advantageously employed include, for example, processes for increasing the oxygen content of blood and tissues; oxygenation of wounds to increase the rate of healing and to reduce infections; oxygenated organ transplant storage media; tumor oxygenation for radiation therapy and chemotherapy; lung bypass by oxygenated liquids in case of pulmonary deficiencies; treatment for carbon monoxide poisoning; mouthwashes, dentifrices; topical, including cosmetic treatment media; contact lens treating solutions; and cell level therapeutic applications. 
     Moreover, it is known that oxygenated liquids can be advantageously employed as solvents for physiological saline isotonic solutions, especially when kept in sealed, sterile containers. Such saline solutions may be prepared by dissolving a sodium concentrate into an oxygen enriched liquid. Alternatively, prepared saline solutions may themselves be subjected to the oxygenation process. Oxygenated saline solutions can provide a more direct and efficient way of providing oxygen to the bloodstream than having the oxygen absorbed thereinto through the stomach lining or intestinal wall, as is done through consumption of an oxygenated beverage. 
     As a further example, oxygenated liquids may be advantageously employed in some disinfection processes. Such disinfection processes are those in which a very high level of dissolved oxygen serves to kill microbial life in the same manner as does chlorine or ozone. These oxygen concentration levels would exceed those resulting after dilution in a biomass for aerobic treatment thereof as described above. For example, it was found that bacteria in a petri dish was killed when merely subjected to oxygen-enriched water having a dissolved oxygen level of about 50 to 70 mg/l. It has also previously been speculated that rather than subjecting certain microbial life to a disinfectant comprising an oxygenated liquid, a disinfection process may instead involve oxygenating a liquid contaminated with microbial life, whereby the disinfection would take place during the oxygenation process. 
     Regardless of the use to which oxygenated liquids are put, means for achieving increased levels of dissolved oxygen in a liquid efficiently is desirable, as are means for doing so at high rates of production. 
     Currently, among the most effective methods and apparatuses for saturating a liquid with oxygen on an industrial scale are those disclosed in U.S. Pat. No. 5,766,490, issued Jun. 16, 1998, and entitled “Oxygenating Apparatus, Method For Oxygenating Water fan Therewith, and Applications Thereof”, which is expressly incorporated herein by reference, and in U.S. Pat. No. 6,120,008, issued Sep. 19, 2000, and entitled “Oxygenating Apparatus, Method For Oxygenating a Liquid Therewith, and Applications Thereof”, which is also expressly incorporated herein by reference. 
     According to the process disclosed by U.S. Pat. No. 5,766,490, a sealed enriching space is provided which includes a venturi mixer through which liquid to be oxygenated upwardly flows, the oxygen gas introduced to the liquid in the venturi throat. This method and apparatus works well, producing an oxygen-enriched liquid having at least 40 mg/l of dissolved oxygen at a rate of approximately 50,000 gallons per day (gpd), but does not take full advantage of the mixing potential offered by a venturi mixer or injector. 
     According to the process disclosed by U.S. Pat. No. 6,120,008, a sealed enriching space is provided which includes a single venturi mixer through which liquid to be oxygenated flows downwardly, the oxygen gas introduced to the liquid in the venturi throat. The pressure of the liquid/oxygen admixture is raised as it flows through a diffuser as it exits the venturi, whereby the buoyancy of the oxygen bubbles therein is increased. These large bubbles float upwards against the downward admixture flow and are broken up into smaller bubbles by a shock wave established in the diffuser by the high rate of liquid flow therethrough. The smaller bubbles are more readily absorbed into the admixture. This method and apparatus works well, producing an oxygen enriched liquid having 160 mg/l oxygen at a rate of approximately 100,000 gpd. 
     A method and apparatus for producing an oxygen enriched liquid having even greater oxygen concentrations than may be achieved through prior apparatuses and processes is desirable, particularly where the higher oxygen concentrations is realized in a liquid post-process at atmospheric pressure. 
     Further, an apparatus which may be easily cleaned in place by providing a reverse flow of a cleaning liquid therethrough, which is particularly useful in liquid food preparation environments, is also desirable. 
     SUMMARY OF THE INVENTION 
     Throughout the specification, drawings and the claims, “water” is meant to include any still or effervescent liquid intended to be enriched with oxygen, and “liquid” is meant to include water and any other still or effervescent liquid that is capable of super oxygenation, including flavored water and other ingestive beverages, and saline solutions. 
     Objects of the present invention include enabling the production of a liquid enriched with dissolved oxygen at higher oxygen concentrations, particularly at atmospheric pressure, than has been possible through apparatuses and processes according to the prior art, and to do so at industrial scale, continuous production rates. 
     Another object of the present invention is to provide improved aerobic, therapeutic and fermentation processes, and saline solutions, employing liquids highly enriched with oxygen in accordance with the present invention. 
     The present invention provides an apparatus for oxygenating a liquid, including a liquid pump, supply piping having an inlet connected to the pump and an outlet, first and second injectors and a chamber. The first injector has a liquid inlet forming a nozzle, a liquid outlet and an oxygen inlet, the first injector oxygen inlet intermediate the first injector liquid inlet and outlet, the supply piping outlet connected to the first injector liquid inlet. The second injector has a liquid inlet forming a nozzle, a liquid outlet and an oxygen inlet, the second injector oxygen inlet intermediate the second injector liquid inlet and outlet, the first injector liquid outlet in communication with the second injector liquid inlet, whereby liquid flows through the first and second injectors in series, each of the first and second injector oxygen inlets provided with a source of oxygen gas. The chamber has a liquid inlet and a liquid outlet, the second injector liquid outlet in communication with the chamber liquid inlet, whereby liquid flows through the second injector and the chamber in series. 
     The present invention also provides a process for enriching a liquid with oxygen, which includes the steps of: (a) introducing a liquid under pressure into a first injector and flowing the liquid downwardly through the first injector; (b) introducing oxygen into the liquid as it flows through the first injector to mix the liquid and oxygen; (c) introducing the admixture of liquid and oxygen resulting from the step (b) under pressure into a second injector and flowing the liquid downwardly through the second injector; (d) introducing oxygen into the admixture as it flows through the second injector to further mix the liquid and oxygen; (e) introducing the admixture of liquid and oxygen resulting from step (d) into a chamber, wherein undissolved oxygen is released from the admixture introduced into the chamber and is collected in the chamber; and (f) recovering an oxygen enriched liquid from the chamber. 
     The present invention also provides a physiological saline solution which includes as the solvent an oxygen enriched liquid, the liquid having an oxygen concentration level of at least about 160 mg/l. The present invention also provides a process of preparing a physiological saline solution which includes the steps of: providing an oxygen enriched liquid having an oxygen concentration level of at least about 160 mg/l; and dissolving a sodium concentrate into the oxygen enriched liquid. 
     The present invention involves processes for using oxygen enriched liquid prepared in accordance with the preparatory process of the present invention and by the use of the apparatus of the invention. These processes of use include aerobic, disinfection, therapeutic and fermentation processes advantageously employing oxygen-containing liquids, as described above. 
     If desired, liquids treated in accordance with the present invention can also be made effervescent by the addition of a gas such as carbon dioxide. If carbon dioxide is added after the dissolution of the oxygen in the water, then it will displace a portion of the dissolved oxygen. It has been found, however, that an effervescent liquid can be further enriched with oxygen to a substantial degree after the addition of the carbon dioxide. Even more oxygen can be dissolved in the liquid if the liquid being enriched with the oxygen is chilled at the time of the oxygen enrichment. To an even greater extent than achievable by chilling the liquid, the solubility of oxygen in a liquid may be increased by increasing the pressure of the liquid and oxygen admixture. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a first perspective view of one embodiment of an apparatus according to the present invention; 
     FIG. 2 is a second perspective view of the apparatus of FIG. 1; 
     FIG. 3 is a plan view of the apparatus of FIG. 1; 
     FIG. 4 is a schematic view of the apparatus of FIG. 1; and 
     FIG. 5 is a fragmentary sectional side view of the debubbler chamber of the apparatus of FIG.  1 . 
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated or simplified in order to better illustrate and explain the present invention. The exemplifications set out herein illustrate embodiments of the invention in alternative forms, and such exemplifications are not to be construed as being exhaustive or to limit the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1-4 illustrate oxygenating apparatus  10 , one embodiment of an apparatus according to the present invention. Apparatus  10  comprises frame  12  which forms a parallelepiped. Within frame  12  is mounted pump assembly  14  which comprises electric motor  16  and centrifugal pump  18 . Motor  16  may be a 20 horsepower, 3-phase electric motor which rotates at a speed of 3500 rpm. Pump  18  may be Model SSV manufactured by Goulds Pumps and directly driven by motor  16 . The liquid to be enriched with oxygen is supplied to inlet  20  of the centrifugal pump  18  and is forced under pressure from outlet  22  of the pump and through supply piping  24 . Supply piping  24  is two inch outside diameter stainless steel 316L. The liquid forced from the pump is initially conveyed vertically upward through supply piping  24 , and then downward to the inlet of first injector  26 . First injector  26  is a venturi-type injector having a nozzle for an inlet and a diffuser for an outlet, with a throat disposed between the inlet and outlet; oxygen gas is provided to the gas inlet at the throat as described further hereinbelow. First injector  26  may be, for example, Mazzei Model No. 1584. The outlet of the first injector is fitted to the inlet of first diffuser/expander  28 , the outlet of which is fitted to first interconnecting conduit  30 . Notably, in apparatus  10  the inlet of first injector  26  is approximately 10 feet 7 inches above the floor on which the apparatus sits. First interconnecting conduit  30  is four inch outside diameter stainless steel 316L. 
     The liquid and oxygen are introduced and mixed within first injector  26 ; the admixture then continues downward and then vertically upward through first interconnecting conduit  30 , and then downward to the inlet of first nozzle/reducer  32 . The unlabeled arrows depicted in the drawings indicate the flow of liquid through apparatus  10 . The outlet of first nozzle/reducer  32  is fitted to the inlet of second injector  34 . Second injector  34  may be identical to or similar to first injector  26 , having a nozzle for an inlet and a diffuser for an outlet. It is to be noted that both first and second injectors  26 ,  34 , respectively, are each substantially vertically oriented such that the liquid flow therethrough is downward. 
     The outlet of second injector  34  is fitted to the inlet of second diffuser/expander  36 , the outlet of which is fitted to second interconnecting conduit  38 . Second interconnecting conduit  38  is three inch outside diameter stainless steel 316L. As will be discussed further hereinbelow, the liquid and oxygen admixture which is provided to the inlet of second injector  34  is further mixed with additional oxygen in the second injector. Downstream of the second injector the admixture, now containing additional oxygen, is directed downward through second interconnecting conduit  38  and then vertically upward through conduit  38 , and then downward to inlet  40  at the top of debubbler chamber  42 . Debubbler chamber  42  is ten inch outside diameter stainless steel 316L and is approximately six feet in length. Notably, the joints between the interconnected piping, conduits, injectors, reducers, expanders and the debubbler chamber may be provided with Teflon seals  43 , which are of the type preferably used in food production environments, for such seals are resistant to absorption of food substances. Alternatively, other types of suitable seals may be used. 
     The admixture of liquid and oxygen flows slowly downward through debubbler chamber  42  and through second nozzle/reducer  44  which comprises the lowermost portion of chamber  42 . The inlet of third nozzle/reducer  46  is connected to outlet  48  of second nozzle/reducer  44 . The outlet of third nozzle/reducer  46  is attached to the inlet of outlet conduit  50 , which is two inch outside diameter stainless steel 316L. 
     Valve means are provided in outlet conduit  50  to provide the appropriate internal pressure within debubbler chamber  42 , the supply piping and the conduits of apparatus  10  as described further hereinbelow; the oxygenated liquid recovered from outlet  52  of conduit  50 , which may be remote from apparatus  10 , is at substantially atmospheric pressure (1 atm or 14.7 psia). 
     Oxygen gas inlet  54  of first injector  26  is attached to a source of oxygen gas which may be, for example, a container of compressed oxygen provided with a pressure regulator (not shown), the container and regulator attached to frame  12  and comprising apparatus  10 . Alternatively, the source of pressurized oxygen may be external to apparatus  10 . Oxygen outlet fitting  58 , provided in top portion  66  of debubbler chamber  42 , is connected to one end of return line  68 ; the other end of return line  68  is fitted to oxygen gas inlet  56  of second injector  34 . Oxygen gas available in the top portion of chamber  42 , above the liquid level therein, is provided to gas inlet  56  of the second injector. The flow of liquid through the throat of second injector  34  establishes a vacuum at oxygen inlet  56 , which draws the available oxygen gas from the top portion of chamber  42 . Moreover, as described further hereinbelow, the oxygen gas located in top portion  66  of chamber  42  is under pressure, and is thus urged through return line  68  to injector  34 . 
     Referring now to FIG. 5, it can be seen that liquid level control valve  60 , comprising downwardly depending tube  62 , is attached to fitting  64  provided in the top wall portion of debubbler chamber  42 . Tube  62  of level control valve  60  extends downwardly from fitting  64  into the interior of the debubbler chamber; the free end of tube  62  is located approximately ten to twelve inches below fitting  64  and ordinarily extends below the liquid level in the chamber. The purpose of level control valve  60  is to maintain a minimum height of liquid and oxygen admixture within debubbler chamber  42  by relieving excessive oxygen gas buildup in the chamber, which might otherwise force the liquid level in the chamber downward. Should the level of the admixture be forced downward under the influence of oxygen gas pressure in the top portion of chamber  42  to a level below the terminal or free end of tube  62 , oxygen gas will be vented to atmosphere through level control valve  60 , thereby relieving the pressure on the surface of the admixture, and allowing it to rise. 
     Notably, oxygen outlet  58  is disposed well above the free end of tube  62 , and during normal operation of apparatus  10 , with the surface level of the liquid within the debubbler chamber at a height above the free end of tube  62 , oxygen under pressure is urged through outlet  58  and oxygen return line  68  to second injector  34 . This recirculated oxygen is again introduced into the liquid and oxygen admixture in second injector  34 , thereby continuously providing oxygen to the process by which the liquid is thoroughly enriched with oxygen. 
     In operation, centrifugal pump  18  provides a flow of 70 gallons per minute (gpm) of liquid at approximately 130 psig to the inlet of first injector  26 . Oxygen gas is provided at approximately 50 cubic feet per hour at 70 psig to oxygen inlet  54  of first injector  26 . The oxygen pressure at inlet  56  of second injector  34  is unregulated, and is received at whatever flow rate is available. It is to be noted, however, that the minimum pressure of the liquid in chamber  42  is regulated by valve means at outlet  52  of apparatus  10 . Thus, in conjunction with level control valve  60 , an oxygen gas pressure of approximately 85 psig, which is substantially equivalent to that of the liquid discharge pressure from the apparatus, is maintained in top portion  66  of chamber  42 . 
     Further, unlike the absorber disclosed in above-mentioned U.S. Pat. No. 6,120,008, debubbler chamber  42  is not provided merely to provide increased residence time for the oxygen in the admixture, during which the oxygen is allowed to be further absorbed into the admixture. Rather, the sole intended function of the debubbler chamber, through which the liquid slowly flows downward, is to allow a considerable period of time for undissolved gases or large bubbles  72  (FIG. 5) to remove themselves from the admixture, to thereby avoid the nucleating of small bubbles  74  when large bubbles  72  would otherwise pass over some downstream anomaly within and outside of apparatus  10 ; such an anomaly would create a pressure shear through which large bubbles  72  would tend to absorb small bubbles  74 . The direction in which bubbles  72  and  74  flow are indicated by the arrows individually associated therewith in FIG.  5 . It can be seen that small bubbles  74  flow with the liquid through chamber  42 , whereas large bubbles  72  float upwards, against the flow of liquid in the chamber. Thus, in the debubbler chamber, large bubbles  72  are provided a means to exit the admixture and oxygen  76  from those large bubbles is recirculated to second injector  34 , where it is reintroduced to the liquid stream. This process continues until the admixture exiting the debubbler chamber comprises only fine bubbles of oxygen in liquid; the absence of large bubbles reduces the likelihood of the small bubbles being nucleated as they experience an anomaly within or outside of apparatus  10 . 
     Additionally, as the liquid and oxygen admixture is introduced into chamber  42  through its inlet  40 , via flow stream  78 , the admixture tumbles through pure oxygen gas  76  which is collected in upper portion  66  of the chamber, between upper wall  80  of the chamber and surface level  82  of the admixture within the chamber. The effect of the liquid tumbling through the pure oxygen in the top of the chamber provides internal aeration of the liquid under pressure and further contributes to the absorption of oxygen by the liquid. The cushion of pure oxygen in top portion  66  of debubbler chamber  42  is not critical to the inventive process, although it is estimated that the abovementioned internal aeration provides an additional one to two percent, by weight, of total oxygen to the admixture recovered from apparatus  10 . 
     Important to the inventive process is that the volume of debubbler chamber  42  is large enough to provide a slow flow velocity therethrough, thereby providing ample time for removal of the bulk of undissolved gases  72  from the admixture therein. The goal is to slow the flow velocity of the liquid admixture flowing through the debubbler chamber to sufficiently allow gases  72  to remove themselves from the liquid through surface  82  of the liquid admixture. Thus the diameter of chamber  42  is substantially larger than the conduits and supply piping of apparatus  10 . Those skilled in the art will now appreciate that the inventive process purges large oxygen bubbles  72  from the admixture within chamber  42 , and that if large bubbles  72  were allowed to remain in the admixture they would attract small bubbles  74  as the large bubbles pass a pressure shear downstream of the debubbler chamber, internal or external to apparatus  10 , resulting in the nucleation of the small bubbles into the large bubbles and the removal of the small bubbles from the admixture. 
     The process of the present invention yields an oxygen-enriched liquid received from outlet  52 , at atmospheric pressure, which has a dissolved oxygen level of at least about 160 mg/l at a flow rate of approximately 70 gpm or approximately 100,000 gpd. 
     Notably, apparatus  10  contains no static or dynamic turbulent mixers in any of its conduits or the debubbler chamber, which promotes easy cleaning of apparatus  10 . Such turbulent mixers may become clogged with debris or residue, depending on the nature of the liquid conveyed through the apparatus. Apparatus  10  may be cleaned in place by reversely flushing the apparatus with a cleaning liquid, which may be pure water or an appropriate solution. This is done by providing a flow of the cleaning liquid into apparatus outlet  52  and allowing the cleaning liquid to reversely flow through the debubbler chamber, the conduits and supply piping, and the injectors. The cleaning liquid exits apparatus  10  through inlet  70  of the supply piping which is, during cleaning, disconnected from outlet  22  of pump  18 . 
     While this invention has been described as having a particular design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.