Patent Application
20080025870
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limited. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected,” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect. Finally, as described in subsequent paragraphs, the specific mechanical configurations illustrated in the drawings are intended to exemplify embodiments of the invention. Accordingly, other alternative mechanical configurations are possible, and fall within the spirit and scope of the present invention.
The present invention includes multiple aspects that can be implemented or used independently or in combination. One aspect of the present invention relates to separating a water soluble gas, such as chlorine dioxide, from a solution. In another aspect of the invention, that gas is then used for the sterilization or sanitation of items, such as food, food storage containers, food processing equipment, other food contact surfaces, medical devices, and the like. In yet another aspect of the invention, that gas is then decomposed, deactivated, or otherwise neutralized after contacting the item.
The present invention has particular utility for treating, cleaning, disinfecting, sanitizing, and/or sterilizing an item, such as a container for food, a medical device, and the like. One particular embodiment of the invention provides a method and apparatus for the sterilization or sanitation of an item, such as an empty food container, other food contact surfaces, food items, medical devices, and the like. The invention can be practiced with relatively small food containers such as bottles, cans, cartons, and other food storage containers on a filling line that demand a sterilized, sanitary or aseptic condition or reduced microbial concentration. For instance, aseptic packaging may be desirable in some food applications for extended shelf life. However, this invention is not limited to aseptic requirements. Rather, containers or other surfaces can be treated for other reasons as well. Additionally, the invention can be adapted for use to sanitize or sterilize food processing equipment, such as pipes and large tanks or containers used for storing and transporting bulk quantities of food items or used for fermentation in any biotechnology industry, such as alcohol, beer, or pharmaceutical production.
In some particular embodiments, chlorine dioxide gas is the preferred gas for use in the sterilization or sanitation process. Although chlorine dioxide gas is the preferred gas for use with the methods and apparatuses described herein, other gases having known sterilization and/or sanitation capabilities can be used.
For embodiments utilizing chlorine dioxide, the chlorine dioxide gas can be initially produced as part of a chlorine dioxide solution and then removed from the solution. For example, in one particular embodiment, the chlorine dioxide solution can be produced according to the process taught in U.S. Patent Application Publication No. 2003/0064018, which is hereby incorporated by reference. In summary, this patent application teaches one particular process in which sodium chlorite is fed through an ion exchanger and a catalyst to quickly and efficiently generate a chlorine dioxide solution. However, as indicated above, other processes can be utilized to generate a chlorine dioxide solution. Such processes fall within the spirit and scope of the present invention.
Once a solution containing chlorine dioxide (or other gas) is generated, the chlorine dioxide can be removed from the solution containing chlorine dioxide. The chlorine dioxide can be removed from the solution many ways. For example, it can be heated, shaken or otherwise agitated, sprayed or atomized, and the like to cause the chlorine dioxide gas to disassociate from the solution. In one particular preferred embodiment, a vacuum is applied to the solution to remove the chlorine dioxide gas from the solution.
Putting a vacuum on a solution containing chlorine dioxide has been shown to reduce the amount of chlorine dioxide in the solution. Specifically, the vacuum causes the gas to be released from the solution into the atmosphere of the vacuum. By repeatedly exposing a chlorine dioxide solution to a vacuum, the levels of chlorine dioxide generally continue to reduce. Accordingly, in some embodiments, an intermittent or timed vacuum can be applied to a solution to maximize the extraction of chlorine dioxide gas from the solution.
Although many different vacuum devices can be used to extract chlorine dioxide from a solution,
In operation, the vacuum has four phases of operation, as illustrated in
Once the chlorine dioxide solution is drawn into the cylinder via the intake stroke, the vacuum stroke illustrated in
Once the piston reaches the opposite end (i.e., opposite the inlet and outlets) of the cylinder, the vacuum stroke is complete and the chlorine dioxide gas discharge stroke begins. During this discharge stroke, the piston is driven toward the gas outlet and the valve located in the outlet is opened to allow the extracted chlorine dioxide gas to exit the cylinder. Once substantially all of the gas is forced out of the cylinder during this stroke, the outlet valve for the gas is closed and the outlet valve for the solution is opened (as shown in
During operation of an entire system, one or more vacuum devices can be used in series, in parallel, or in a combination of series and parallel. The number and size of vacuum devices included in an entire gas extraction system will depend upon the amount of gas needed at peak demand. Smaller operations will need fewer and/or smaller vacuum devices than larger operations, such as a larger international bottling plant.
Although the vacuum device is described specifically with reference to a chlorine dioxide solution and chlorine dioxide gas, this vacuum device can be utilized to remove other water soluble gases from a solution. For example, this may also have utility removing ozone, oxygen, ammonia, peracetic acid, and the like, from a solution.
Once the chlorine dioxide gas is extracted from the solution, the gas can be immediately used to clean, sanitize, sterilize, and/or disinfect various items or surfaces. For example, in one particular use, the chlorine dioxide gas can be injected into individual food containers, such as bottles, jars, cartons, cups, and the like. In other uses, the chlorine dioxide is injected into piping, vessels, tanks, and other food processing equipment. In yet other uses, the chlorine dioxide gas in pumped into a chamber, housing, or the like containing various items, such as food, medical equipment, and the like. In yet other embodiments, as will be described in greater detail below, the chlorine dioxide gas can be reintroduced into a pure or purified water stream to provide a highly pure chlorine dioxide solution.
Once the chlorine dioxide has contacted the item for a sufficient time to clean, disinfect, sanitize, and/or sterilize the item, the chlorine dioxide can then be eliminated from contact with the item. For example, in one particular embodiment, an ultraviolet light is utilized to decompose or deactivate the chlorine dioxide gas. In other embodiments, the gas can be evacuated by flushing the container with sterile (filtered) nitrogen, air or other suitable pressurized gas. The evacuated chlorine dioxide can then be reused, reintroduced into solution, or neutralized.
As indicated above, the chlorine dioxide gas contacts the item for a sufficient time to clean, disinfect, sanitize, and/or sterilize the item. The exact amount of contact time needed will depend upon many factors, such as the concentration of chlorine dioxide gas in the carrier gas, relative humidity adjacent the item, temperature adjacent the item or in the container, the types of target microorganisms, container surface properties (coated or uncoated), and size of the target container or item.
In one specific use, the various aspects of the present invention can be utilized in combination in a sterilization or sanitation process for relatively small food containers, such as bottles on a filling line. The vacuum device described above is used to extract chlorine dioxide gas from a reservoir or sample of chlorine dioxide solution. The chlorine dioxide gas is then injected into each individual container to disinfect the container prior to filling the container. Once the gas has contacted the surfaces for a sufficiently long time to sterilize the container, the gas can be eliminated from the container. In one specific embodiment, the gas is inactivated by an ultraviolet light. Specifically, the chlorine dioxide gas is exposed to an ultraviolet light of sufficient frequency and wave length for a sufficient period of time to deactivate or decompose the gas. In some embodiments, the gas is exposed to the ultraviolet light long enough such that the residual chlorine dioxide levels fall below the levels allowed in potable water. Some embodiments can utilize a rinse with sterile water to further remove the chlorine dioxide gas from the containers if desired or needed.
In another specific use, the various aspects of the present invention can be utilized while processing food, such as fruit, vegetables, poultry, etc. The vacuum device described above is used to extract chlorine dioxide gas from a chlorine dioxide solution. The chlorine dioxide gas is then injected into a chamber containing the food. The gas can be injected directly onto the food or indirectly onto the food via the surrounding environment. Once the gas has contacted the surfaces for a sufficiently long time, the gas can be eliminated from the chamber or the food can be removed from the chamber. In one specific embodiment, the gas is eliminated or inactivated by an ultraviolet light as described above. Subsequently, the food is removed from the chamber. Alternatively, the food can be removed from the chamber via a conveyor system and any escaping gas can be eliminated via an ultraviolet light located adjacent the exit of the chamber.
In yet other uses, the extracted water soluble gas, such as chlorine dioxide, can be injected in a room (or chamber, container, etc.) to disinfect the room or objects within the room. For example, the chlorine dioxide gas can be used to treat library books or rare art. Additionally, the gas can be used to decontaminate an entire room, such as a room with suspected anthrax and/or mold contamination.
As indicated above, the present invention can be used to create a highly pure chlorine dioxide (or other soluble gas) solution. Particularly, once the gas is extracted from the original solution, the gas can be dissolved into a pure or purified solution, such as purified water. The gas can be dissolved into the pure solution many ways known in the art. For example, in one embodiment, the gas can be dissolved in the solution by bubbling the gas into the solution.
This process of extracting a water soluble gas from one solution and dissolving it in another solution can enable one to make a highly purified solution containing the gas. For example, many chlorine dioxide solutions can contain some impurities that may be undesirable in some applications. For example, some by-products from reactions that produce chlorine dioxide solutions can include chlorate, chloride, chlorite, hypochlorite, and the like. These by-products may be a concern in some applications. Accordingly, the gas can be extracted from the solution and dissolved into purified water to create a highly pure chlorine dioxide solution.
The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention. For example, the examples described above can be modified to apply to food processing equipment, medical devices, etc. Further, various alternatives to the certain features and elements of the present invention may be described with reference to specific embodiments of the present invention. With the exception of features, elements, and manners of operation that are mutually exclusive of or are inconsistent with each embodiment described above, it should be noted that the alternative features, elements, and manners of operation described with reference to one particular embodiment may be applicable to the other embodiments.
Various features of the invention are set forth in the following claims.
