Bisphenol A (BPA)-based phenolic epoxy coatings can be used to protect steel and aluminum food/beverage cans from corrosion. Overtime, BPA may be released into the food/beverage. There may be health concerns over the release.
Non-can steel structures exposed to corrosive conditions for extended period of time have been cathodically protected. Typically, the potential of the steel surface may be polarized (pushed) more negative until the surface has a uniform potential. At that stage, the driving force for the corrosion reaction may be reduced or halted. An impressed current cathodic protection system may protect steel by converting alternating current (AC) to direct current (DC). For example, a pipeline protection system may include an AC power rectifier with a maximum rated DC output of between 10 and 50 amperes and 50 volts. The positive DC output terminal may be connected via cables to an array of anodes (often inert graphite) buried in the ground (the anode grounded). For many applications, the anodes are installed in a 60 m (200 foot) deep, 25 cm (10-inch) diameter vertical hole and backfilled with conductive coke.
Subject matter is particularly pointed out and distinctly claimed in the concluding portion of the present Specification. The foregoing and other features of the present disclosure will become more fully apparent from the following Description and appended Claims, taken in conjunction with the accompanying Drawings. Understanding that these Drawings depict only example embodiments in accordance with the present disclosure and are, therefore, not to be considered limiting of its scope. The disclosure will be described with additional specificity and detail through use of the accompanying Drawings:
The following description sets forth various examples along with specific details to provide a thorough understanding of claimed subject matter. It will be understood by those skilled in the art, however, that claimed subject matter may be practiced without some or more of the specific details disclosed herein. Further, in some circumstances, well-known methods, procedures, systems, components and/or circuits have not been described in detail in order to avoid unnecessarily obscuring claimed subject matter. In the present Detailed Description, reference is made to the accompanying Drawings, which form a part hereof. In the Drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the Detailed Description, Drawings, and Claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Drawings, may be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.
Techniques are generally described herein for protecting food or beverage containers (e.g., cans) using impressed current protection. In various embodiments, containers may be received into at least one conductive bed, each conductive bed having a complementary anode. The containers may then be electrically coupled to a first terminal of a power supply (e.g., negative), and the anode may be electrically coupled to a second terminal (e.g., positive) of the power supply. Resultantly, protective current may be provided to the containers by the anode, as described further below. Other embodiments may be disclosed and claimed.
Referring now to
Reaction at cathode (reduction) (container exterior) may be characterized by the chemical equation:
2H2O+O2+4e−=4OH (1)
whereas, reaction at anode (oxidation) may be characterized by the chemical equation:
2H2O=O2+4H++4e− (2)
That is, at cathode, the moisture (2H2O) and oxygen (O2) present on the container exterior may combine with 4 electrons (4e−) to reduce and form hydroxyl ion (4OH) on the container exterior (Equation (1)). Whereas, at anode, moisture (2H2O) may be formed on the container exterior by oxidation of the oxygen (O2) and hydrogen (4H+) present on the container exterior (Equation (2)).
In various embodiments, food or beverage containers 110 may be steel or aluminum cans designed to can various food or beverages, including but not limited to acidic food or beverages, such as tomatoes, grapefruit juices, and so forth. For steel or aluminum cans, the cans may have a coating to protect the food or beverage, or no coating. In various embodiments, power supply 102 may be a DC power supply as illustrated. In alternate embodiments, power supply 102 may be a rectifier converting AC power supply to DC power supply. Embodiments of conductive bed(s) 102 and anode(s) 104 will be further describe below, including arrangements formed, and associated methods, referencing the remaining Figs.
In various embodiments, a pallet of containers is provided with cathodic polarization of about 120 mv. At that voltage level, correction rate of steel or aluminum containers may be reduced by as much as three (3×) orders of magnitude.
In various embodiments, conductive bed 202 may be reusable. In various embodiments, conductive bed 202 may be constituted with a material of calcined coke breeze. In various embodiments, the thickness of conductive bed 202 may vary, depending on the structural strength, if any, desired. In alternate embodiments, other materials with similar structural and/or electrical properties may be employed instead. In various embodiments, conductive bed 202 may also be provided with a coating of a woven, porous jacket.
In various embodiments, anode 204 may be constituted with an inert material of graphite or platinum coated titanium. In various embodiments, the dimension of anode 204 may vary, depending on the amount or strength of protective current desired. The amount or strength of protective current desired may be dependent on the size and material of the containers. In alternate embodiments, other materials with similar structural and/or electrical properties may be employed instead. In various embodiments, anode 204 may also be coated with a conductive polymer. Coating anode 204 with a conductive polymer may reduce the number anodes required for an application.
From block 604, method 600 may proceed to block 606, “Electrically Couple Containers.” At block 606, a practitioner of the present disclosure, e.g. a bottler, a grocer, or a food/beverage establishment operator, may electrically couple the containers to one of the terminals of a power supply, e.g., the negative terminal. In some embodiments, the coupling may include keeping an end of a wire in contact with a container by e.g. wrapping around, taping or otherwise secure the end of the wire to the container. In other embodiments, the coupling may include electrically coupling containers in adjacent conductive beds. From block 606, method 600 may proceed to block 608, “Electrically Couple Anode(s).” At block 608, a practitioner of the present disclosure, e.g. a bottler, a grocer, or a food/beverage establishment operator, may electrically couple the anode(s) to the other terminal of the power supply, e.g., the positive terminal, thereby enabling protective current to be provided from the anodes to the containers.
Claimed subject matter is not limited in scope to the particular implementations described herein. In the current description, various aspects of claimed subject matter below have been described. For purposes of explanation, specific numbers, systems and/or configurations were set forth to provide a thorough understanding of claimed subject matter. However, it should be apparent to one skilled in the art and having the benefit of this disclosure that claimed subject matter may be practiced without the specific details. In other instances, well-known features were omitted and/or simplified so as not to obscure claimed subject matter. While certain features have been illustrated and/or described herein, many modifications, substitutions, changes and/or equivalents will now, or in the future, occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and/or changes as fall within the true spirit of claimed subject matter.
The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality may be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated may also be viewed as being “operably connected”, or “operably coupled”, to each other to achieve the desired functionality, and any two components capable of being so associated may also be viewed as being “operably couplable”, to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
While certain example techniques have been described and shown herein using various methods, devices and systems, it should be understood by those skilled in the art that various other modifications may be made, and equivalents may be substituted, without departing from claimed subject matter. Additionally, many modifications may be made to adapt a particular situation to the teachings of claimed subject matter without departing from the central concept described herein. Therefore, it is intended that claimed subject matter not be limited to the particular examples disclosed, but that such claimed subject matter also may include all implementations falling within the scope of the appended claims, and equivalents thereof.
This application is related to Attorney Docket No. 117999-172511, entitled “Enclosing Manufacture with a Magnesium Sacrificial Anode for Corrosion Protection,” filed contemporaneously Nov. 25, 2009.