Gas and liquid contact apparatus – Contact devices – Injector type
Reexamination Certificate
2000-04-27
2001-08-28
Thornton, Krisanne (Department: 1744)
Gas and liquid contact apparatus
Contact devices
Injector type
C210S620000, C210S758000, C210S137000, C210S192000, C210S205000, C210S253000, C261SDIG007, C261SDIG007, C261SDIG003, C422S045000
Reexamination Certificate
active
06279882
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for oxygenating a liquid, such as water, a method for oxygenating the liquid, and applications of liquids oxygenated by the inventive apparatus and method.
It is known that various types of liquids are oxygenated, i.e., prepared in solution with oxygen, to achieve various results. For example, consumption of an oxygen enriched beverage has a favorable effect on well being and physical performance. For example, 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, a liquid may be oxygenated to promote bioremediation of contaminated or oxygen-depleted bodies of water, and effective bioremediation requires a high rate of oxygen use. The replenishment of oxygen in groundwater, for example, occurs very slowly. As a result, oxygen levels in the contaminated groundwater systems are often quickly depleted, even when water has been thoroughly aerated before the onset of the bioremediation process. Thus, bioremediation processes are more effective if higher oxygen levels are provided in the groundwater, enabling a desirably greater and more rapid treatment.
It is known to oxygenate still liquids (i.e., liquids which are substantially gas-free) at super-atmospheric pressure with oxygen from an external source. The impregnation of the liquid with gas is usually carried out in sealed vessels or conduits, with the impregnated liquid subsequentially transferred to bottles or other containers in which it is to be marketed, the bottles filled and sealed under super-atmospheric pressure in order to prevent, so far as possible, the escape of oxygen gas from the liquid. Moreover, it is known to intermix oxygen into liquids by passing the liquid through a venturi mixer or injector and introducing oxygen into the admixture at the venturi throat. Further, it is known that a shockwave may be produced in the diverging outlet of a venturi mixer or injector to promote mixing of the liquid and the gas. Generally, venturi mixers or injectors employed in liquid oxygenating apparatuses are oriented horizontally, or vertically and such that the liquid flow therethrough is upwardly directed.
Currently, one of the most effective known method and apparatus for saturating a liquid with oxygen on an industrial scale is described in published International Patent Application WO 97/27146 and U.S. Pat. No. 5,766,490. According to this process, 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 known method and apparatus works well, producing an oxygen-enriched liquid having at least 40 mg/l 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. A method and apparatus providing greater oxygen concentrations and flow rates is desirable.
Further, a method and apparatus which can automatically control various aspects of the process of oxygenating a liquid with only the operator's input of a desired, variable oxygen concentration level would be 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.
Objects of the present invention include enabling the production of a liquid enriched with oxygen at higher oxygen concentrations and at higher, industrial scale, continuous production rates than has been possible in the prior art, and providing for the improved utilization of such super-oxygenated liquids. The liquid to be enriched with oxygen may be chilled or at ambient temperatures, with greater concentrations of oxygen achievable in chilled liquids.
Another object of the present invention is to provide improved aerobic, therapeutic and fermentation processes employing liquids highly enriched with oxygen in accordance with the present invention.
It is known in the art that there are three approaches to achieving a process providing mass transfer of gas into a liquid. The first approach is to provide a large liquid-gas boundary surface area through which the gas may be absorbed into the liquid. The second approach is to provide a driving force between the gas and liquid phases; the magnitude of the driving force directly correlating with the mass transfer rate, which is directly related to the pressure at the liquid-gas interface. The third approach is to increase the mass transfer coefficient by increasing the relative velocity between the interfacing gas and liquid phases, and the turbulent mixing in the liquid phase. These three approaches are combined in the present invention.
The present invention provides a means of maximizing the liquid-gas boundary area, the driving force between the liquid and gas phases, and the mass transfer coefficient, as well as increasing the time over which mass transfer may occur. This is accomplished by providing a liquid oxygenating system in which the liquid flows downwardly through a venturi-type injector having an inlet forming a nozzle, a throat adjacent thereto in which oxygen is introduced into admixture with the liquid, and a diverging, first diffuser portion directly below and adjacent to the throat and in which a shockwave is produced. The shockwave creates many fine bubbles thereby increasing the surface area of the liquid-oxygen interface. There is pressure recovery downstream of the shockwave.
The plurality of smaller bubbles proceeds downward with the flowing liquid into a second diffuser/absorber portion in which the pressure of the admixed liquid and oxygen phases is increased further. In the first and second diffuser/absorber portions, the linear pressure gradient normally associated with increasing liquid depth in a static liquid is augmented, providing increases in the pressure of and pressure gradient in the liquid and gas phases higher than would otherwise be experienced. In itself, the augmented pressure increase occurring in the first and second diffuser/absorber portions increases the driving force between the gas and liquid phases, increasing the concentration of oxygen molecules at the liquid-gas interface as well, circumstances which promote high gas-to-liquid mass transfer. Further, however, the increased axial pressure gradient on the oxygen bubbles increases their buoyancy in the liquid, causing some of them to float upwards against the downward liquid flow. The oppositely directed flow of oxygen bubbles and liquid yields a high relative velocity therebetween, which increases the gas-to-liquid mass transfer, promoting their intermixing. The high relative velocity between the oxygen bubbles and the liquid, and the turbulent mixing of the liquid, keeps the liquid molecule concentration gradient high at the liquid-gas interface; the oxygen molecule concentration of a bubble, however, is fixed by the pressure acting thereon. The differences in concentrations between the gas and the liquid at their interface promotes the absorption of the oxygen into the liquid, the gas penetrating the boundary surface between the two phases. Also, the large upwardly floating bubbles are broken up into an even greater plurality of even smaller bubbles, further increasing the surface area
Littman Howard
Peterson Kent L.
Baker & Daniels
Life International Products, Inc.
Thornton Krisanne
LandOfFree
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