Patent Application
20250171908
Provisional application Ser. No. 18/058,857 filed on Nov. 25, 2022.
At the time of writing this application, there are several “powered anode rod” manufacturers which sell assemblies that generally provide environmental sealing, though by different assembly elements and compositions than what is proposed in this invention, and with differing resulting reliability and useful life.
This invention pertains to a method for utilizing an assembly composed of heat-fused ceramic material that encapsulates an electrically conductive electrode within a rigid element. The purpose of this assembly is to facilitate the implementation of impressed current cathodic protection. Historically, glass-sealed assemblies have been utilized as environmental seals, particularly in applications requiring the conduction of electrical current in harsh environments, such as in spark plugs for combustion engines or in light bulbs. Notably, this specific type of seal has not yet been utilized in the context of impressed current cathodic protection. The adoption of such glass-sealed assemblies in this domain offers advantages, including enhanced reliability, increased longevity, and the potential for reduced cost of corrosion control.
This invention relates to impressed current cathodic protection devices, often termed “powered anodes”, used for controlling corrosion of material in contact with an electrolyte, and to the field of ceramic materials such as glasses used in hermetic sealing, and to the field of glass-to-metal seals, and in particular to compression seals.
For the purpose of this document, “electrolyte” is defined as a non-solid medium, typically a fluid, that facilitates the transfer of electrical potential. This term encompasses a broad range of substances, and examples include tap water and sea water, as well as various other fluids. An electrolyte, in the specified context, serves as a medium through which ions can move, enabling the flow of electric current.
For the purpose of this document, a material which is in contact with an electrolyte and which is of a composition that more readily gives up its electrons than does the material which it is “sacrificing” itself for; in this manner, in operation, the sacrificial anode is dissolved or corroded instead of the element which it is protecting. Typically, in the field of protecting structures made of steel which are in contact with an electrolyte, the sacrificial anode will be comprised of magnesium or aluminum, both which are less noble than steel and therefore both give up the electrons that comprise their mass more easily than that of steel.
For the purpose of this document, a material composition that is comprised in majority part of elemental oxides that can fuse to each other (or the composition to itself) due to sufficient heat; said fusion typically relying upon the formation of covalent or ionic bonds or both (and/or other forces of attraction) at the atomic level. Glass, ceramics, or glass-ceramic composite materials meet this definition, as many contain elements of silicon oxides, aluminum oxides, tin oxides, germanium oxides, etc, which are commonly utilized by those familiar with the art to create such material. Said ceramic material can be crystalline or amorphous or a mixture of both. It can be devitrifying or vitrifying. An example of a “ceramic composite” is a glass with additions of ceramic particles. Companies such as SCHOTT, NEG, Ferro, Corning, and others engage in the production of such materials, often categorizing it as “sealing glass” or “ceramic enamel” or “ceramic”, herein referred to as a ceramic material.
For the purpose of this document, a seal which prevents no more than 0.025 milliliters of water per hour passage through itself, or the the surfaces in contact with it which are intended for sealing, at a pressure of 95 PSI on one isolated side of the seal and atmospheric pressure at sea level and a temperature of 105 degrees fahrenheit for the entirety of the seal. It is preferred that this amount of leakage be minimized beyond this, and that the most robust seal is one that does not allow any passage of any amount of water through its body nor through the surfaces which the seal contacts which are intended for sealing.
For the purpose of this document, a state or condition of matter that is sufficiently resistant to deformation when subjected to external forces so as to be used as intended under expected operating conditions.
For the purpose of this document, a generally rigid element which interfaces with a structure, oftentimes adding additional connectivity or features or enhancements to the structure. Particular to this document, a “fitting” is used to describe an element of an assembly which is fixtured to other elements thereby creating an assemblage. The fitting may most often resemble a pipe nipple but with added features and generally threads on only one end, as well as contains a through-hole passageway that has been sealed closed, and therefore the word “fitting” has been used here rather than “pipe nipple”.
For the purpose of aiding discovery of this invention, the inventor wishes to note that in common speech the invention may sometimes be described under the following terms: hermetically-sealed, glass-sealed, ceramic-sealed anode, powered anode, powered anode rod, impressed current cathodic protection device.
Impressed current cathodic protection (ICCP) has been known to the general public for nearly 200 years since the writings of Sir Humphry Davy made available to the Royal Society in London in 1824, and has since been used widely in the protection of corrodible metals, such as those found in ship hulls, steel reinforcement in concrete, steel pipelines (U.S. Pat. No. 1,807,903), steel oil tanks, water storage tanks, and more. In this process of ICCP, a direct current (DC) power source is electrically connected to the electrolyte that is in contact with the structure that is desired to have protection such that the anodic portion of the outside electrical current source is discharged into the electrolyte, and the structure intended for protection is electrically connected to the cathodic portion of the outside electrical current source, whereby a level of protection is achieved for those electrically conductive elements that are in a cathodic (negative or ground) state relative to an anodic electrolyte.
When ICCP is applied to hot water storage tanks typically found in commercial and residential buildings, often called “water heaters”, it is typically applied by use of a “powered anode” assembly that is inserted through a threaded female “anode port” on the tank and which replaces a factory-installed sacrificial anode. The powered anode assembly can be described as being comprised of three main functional elements, though possibly more real elements in application, but which fulfill three primary functions: (1) a rigid element that fixtures and generally seals the assembly to a structure or tank; (2) an electrically conductive element that is used to transfer an electric current from the exterior of the structure to the interior of the structure and which typically pierces through the center of the rigid element without conducting electrical current to it; (3) an electrically insulative element which prevents short circuit of the electrically conductive element to that of the rigid element of the assembly (if it is electrically conductive), and this same element which often serves to seal the environment of the inside of the tank from the environment outside the tank. Altogether, these aforementioned functional elements create what is often termed a “powered anode” or “powered anode rod” or “powered anode rod assembly”, that is: the assembly which is installed on the electrolyte-containing-structure and which is connected in the least to the anodic branch of electrical current from a power supply and which is typically comprised in part by an electrode which discharges the anodic current into an electrolyte within the structure.
In greater detail, generally the structures upon which these powered anode assemblies are installed upon are often called “hot water storage tanks” or “water heaters”, and contain a fluid, typically water, and are often under pressure (often measured in “pounds per square inch”, (PSI)) from city or well water supplies as is necessary for proper functioning of the hot water circuit for which it is used. This pressure is typically in the range of 40 PSI up to 125 PSI, but these tanks are often outfitted with pressure relief valves that do not open until about 150 PSI is reached, and so it can be stated with confidence that any powered anode assembly fitted to a tank should through its lifetime of use safely withstand pressure of 150 PSI or greater without leaking, and should typically include a margin of safety factor such that it is preferable that it should survive the same pressures as the tank, noting that tanks are often tested to survive a pressure of up to 300 PSI. It is preferable that these ICCP devices survive for a lifetime operation of typically no less than 2 years, and typically more than 5 years, and preferably longer than 10 years without leaking while under pressure and typically at an operation temperature of 115 to 180 degrees fahrenheit. Often, the first functional element to fail in an ICCP device is the dielectric (electrically-insulating material) or environmental sealing element which is most often a single element that is fulfilling both functions. Prior art and standard practice in ICCP assemblies is to seal the electrode with a polymer, typically polytetrafluoroethylene (PTFE) or similar, or an elastomer such as silicone or similar, or a thermosetting epoxy, or a combination of the above. Failure of this sealing element can occur in less than one year in assemblies that use epoxy, and can often be attributed to a mismatch of the coefficient of thermal expansion rates of the materials, which causes shear disbondment between the epoxy and the metal of the electrode or the metal of the exterior fixturing element and is most likely due to temperature fluctuations during operation which cause [differing rates of] expansion or contraction of the elements in the assembly after which there is a loss of adhesion which can cause a leak to occur. Failure of assemblies that use a compression seal of PTFE or another polymer can most likely be attributed to aging and relaxation or creep of the polymer, a well-known phenomenon, which then allows a small gap or a zone between elements of lower compressive force than that of the pressure within the structure, and thereby a leak can occur. Elastomeric seals can also fail due to degradation of the elastomer, which is most likely caused by a combination of heat aging and ion exchange through the material, the ion exchange being driven between the anodic centrally-located electrode and the cathodic fitting or tank. It is worth noting that in the year of this writing of 2023, and for many decades prior, that hot water storage tanks are coated on their interior for corrosion protection not by polymers such as epoxies and elastomers, but by ceramic materials, often called ceramic or glass or enamel. It has long been obvious and common practice in the field that materials such as copper, brass, stainless steel, and ceramic materials can survive the environment found in a hot water storage tank much longer than polymers can.
Therefore, the novelty found in this present invention is by the method of using ceramic material as the sealing element in an ICCP assembly rather than polymers so as to take advantage of this material's low-to-non-existent creep, extreme tolerance for heat, and slow hydrolysis; attributes, when used in an ICCP assembly, which can bestow advantages of increased reliability, longer lifetime, increased operation temperature, and lower lifetime costs to manufacturer and user.
U.S. Pat. No. 1,184,813 describes a metal-to-glass compression seal which utilizes materials of substantially differing rates of thermal expansion to provide an assembly that can provide an environmental seal even while passing an electrical current. The assembly is made, as follows, described in order of outermost components to innermost: a metal (typically of highest CTE in the assembly) element is circumferentially located around a glass element which is then pieced through by another electrically conductive metal element; the preferred rates of thermal expansion being that the outermost element is of highest CTE, the CTE progressively becoming less, therefore resulting in an assembly that, if fashioned at a temperature substantively above its use-temperature that therefore upon reduction to said use-temperature results in an assembly of elements that are placed in generally radial compression (by the outermost metal element) to a central axis, providing a robust seal, furthermore enhanced if the assembly was made when the glass was at a temperature high enough so as to wet and adhere to the elements it contacts. It is generally this type of seal that is herein newly applied to ICCP assemblies.
U.S. Pat. No. 1,807,903 describes the use of electrical current to preserve steel in contact with an electrolyte, finding that placing the steel in a cathodic state relative to an anodic electrolyte prevents, with sufficient electrical current present, corrosion of the steel in the areas that are contacting the electrolyte. This method has become known as “impressed current cathodic protection” (ICCP), and it is in application of this method that this present invention proposes to utilize, in general terms, a glass-metal seal.
US20110223475 describes a glass and ceramic seal structure for use in energy storage devices, which includes the use of a sealing glass to join an electrically-insulating ceramic to an ion-conducting ceramic, and so claims coating compositions of the invention for resistance to the sodium or metal halides found in energy storage devices, which is not a claim of this present invention of applying a glass seal to ICCP.
This invention is that of the method of utilizing an assembly comprising of a ceramic material to fixture an electrically conductive element inside a rigid element for application of said assemblage to structures in contact with an electrolyte for the purpose of utilizing an electrical current to protect said structure from corrosion under the method of “impressed current cathodic protection” (ICCP). Therefore, the goal of the invention is to provide corrosion protection by way of the method of ICCP by utilizing the novel step or method of using an assemblage which uses ceramic material to fixture an interior electrically conductive element inside a rigid element. Until the inventor's development of this, no such process existed, and the inventor and author of this present application, as of August of 2023, produces and sells such-made ICCP devices under his brand “STOLTCO”. It is most beneficial for the ceramic material to create a hermetic seal around the interior electrically conductive element to the walls of the exterior element, although there may be cases where this is not required and the ceramic material will only fixture the elements into an assemblage and that a different material will be used to seal against fluid or pressure transfer (or both).
In summary, this novel application of sealing is comprised of:
In the aforedescribed assembly of elements, it is desired (but not required) that the rate of thermal expansion of each element to be sequentially lesser from the outermost to the innermost; the reason for this is that if the innermost element is of the least thermal expansion rate, and if the assembly is made at a temperature that exceeds normal operation, then during normal operation all elements that are interior of the outermost element will be in a compressed state; preferably a radially-compressed state due to outer components exertion of force. In this orientation, so long as the outermost component is of sufficient tensile strength to bear the tensile strain placed upon it due to its shrinking upon the inner elements, the assembly as a whole, given the material characteristics of each element, becomes quite robust and resists injury caused by mechanical force, or fluid or gas pressures, or changes of temperature. In this assembly, if the innermost element is of a higher thermal expansion rate than that of the ceramic sealing material, it is then preferred that the element outside of, or otherwise generally encompassing, the ceramic material be of a higher thermal expansion rate than the ceramic material; furthermore, it is preferred then that the ceramic material be of as low of a fusing temperature as possible while remaining a solid at expected operation/use temperatures, and at its fusing temperature have good ability to “wet” any material it is generally encompassing. The low fusing/wetting temperature of the ceramic material generally allows for most of the shrinking of the innermost element to have occurred during a plastic or liquidus phase of the ceramic material, therefore aiding in a reduction of tensile stresses in the ceramic material as it cools and also aiding in forcing the ceramic material to have good contact with the electrically conductive element interior to it and subsequently stronger fixturing and greater probability of an environmental or hermetic seal. This seal, with an outside encompassing element generally in tension, and inner elements generally in compression is commonly known as a “compression seal”. Because this above-described seal is made of fused oxides, it is generally much more resistant to heat and aging than most methods of polymer seals.
In the most simple embodiment, this rigid exterior element is a solid material band which is typically the outermost circumferentially located component to all other components and of sufficient tensile strength to withstand the stress of its shrinking upon the interior components, and of sufficient strength to withstand fixturing and pressure forces, as well as of a material that is not easily degraded by the environment it will encounter. This rigid exterior element of the assembly is typically either of a metal or of a ceramic material, and in either case it is generally rigid so as to aid in fastening and sealing to a structure for application of ICCP. In the case of a metal it should be of sufficient tensile strength, due to its composition and geometry, to withstand the tensile stresses induced by shrinking from the temperature required to fuse the interior-located ceramic material to that of a lower temperature typically encountered during assembly, shipping, and use. Generally, this metal will be a stainless steel alloy as these alloys well-provide the characteristics desired for this assembly and application such as: corrosion resistance for areas not in contact with electrolyte, tensile strength, and relatively high rate of thermal expansion in comparison to titanium and most ceramic materials. This exterior rigid element can be comprised of a ceramic material such as commonly molded ceramics of zirconia or alumina and others, and amorphous glasses and others. This rigid exterior element may be absent in some assemblies that are typically comprised of three elements of an assembly, and therefore present as one of two elements, whereby the other element is the electrically conductive element, and this rigid element is then comprised of electrically insulative ceramic material which may suffice to fasten directly to the structure intended for ICCP protection. It should be noted that although most embodiments will utilize a metal for a rigid exterior element, that other materials such as ceramics may suffice or in some cases be preferred, and that in these scenarios said rigid element may be low in tensile strength, and therefore when the assemblage is completed it may rely less upon a compression type seal, and more upon elements more closely matched in CTE and upon wetting and adhesion of the ceramic material to the contacting elements of the assemblage.
A type of ceramic material that can be used in this invention is commonly available in the electronics industry for hermetic sealing and is typically sold as “sealing glass”, although in practice the material used in this invention can be a glass or a ceramic, or a “glass-ceramic” combination of the two, and can be vitrifying or de-vitrifying, and can be amorphous or crystalline. The ceramic material need not be of a specific oxide makeup, as many various combinations of oxides will suffice for fusion and subsequent conglomeration into a ceramic monolithic seal, and these various combinations may have differing points of fusion and conglomeration, yet the ceramic material will preferably have a temperature of fusion sufficient to wet the surfaces of the materials it contacts, or in the least to become soft enough so as to fill voids created by the expansion of other elements of the assembly during the heating step of production of the assembly where, upon cooling and contraction, a compression seal sufficient for the goals of the assembly is achieved. In an assembly that relies upon a production method of fusing the ceramic material to itself, such as is the case of pieces of frit adhering to each other to become a monolithic element, then the temperature of the fusing is most likely limited at its high end by any detrimental changes it may induce in the other elements of the assembly which are heated with it; therefore, the phase-change points or melting points of the other materials are likely to be considered as the maximum temperature of production of the assembly. Generally, it is preferred that ceramic material fusion occurs at less than 1800-celsius as temperatures above this are energy intensive, and due to the high temperature most metals are precluded from use in the assembly. It is beneficial to have a low fusion temperature of the ceramic material, as energy use and time (and therefore cost) is saved, yet this minimum must not be so low as to be detrimental to the finished assembly, and so, due to likely applications to hot water storage tanks which may at times reach 100-degrees celsius, and desiring an allowance for a factor of safety, fusion of the ceramic material as is minimally suitable for the assemblage should occur at no less than 180-degrees celsius. Generally, it is preferable that the ceramic material fuse at a temperature below 850-degrees celsius to keep production costs low and to allow sealing to other elements of the assembly to comprise of commonly-available materials which may undergo detrimental phase-change above this temperature. It is also preferred that fusion be above 200-degrees celsius to provide an ample factor of safety during use.
Production of the assembly may be made at temperatures lower than the wetting temperature of the ceramic material if a pre-form of the ceramic material is made that has a close fit to the interfacing components, such that the assembly is heated to a deformation temperature of the ceramic material which is then forced by gravity, or by gas or mechanical pressure into greater and more intimate contact with the surrounding elements, afterwhich upon cooling the outermost element contracts more greatly upon the ceramic material element to form a compression seal.
The ceramic material may be wholly a sealing glass or ceramic or a combination of glass and ceramic such as ceramic particles mixed into a glass, any part of which may be vitrifying or devitrifying. In most embodiments, an important purpose that the ceramic material will perform is that of an electrical insulator between the assembly's interior-located electrically conductive element, and the assembly's exterior-located rigid element which is typically comprised of an electrically conductive metal, the ceramic material thereby preventing short circuit within the assembly and therefore the ceramic material typically used in this invention is generally preferred to be electrically insulative to the extent that it does not provide a short circuit path from the electrically conductive element it encompasses to other elements of the assembly or to the structure as this would impair or stop the functioning of the ICCP process. An alternative embodiment which can use a ceramic material that is electrically conductive (versus electrically insulative) is an assembly wherein the rigid outer member that is in contact with the electrically conductive structure during operation is itself electrically insulative (such made of a ceramic material), or when an ICCP assembly that uses an electrically conductive outer rigid member is to be installed on a structure or an area of the structure which is known to be electrically-insulated from the areas of the structure which are intended for corrosion protection; in this way, the path of electrical current from its source to the electrolyte is preserved from short circuiting directly upon the areas of the structure intended for its protection. In typical embodiments however, a generally electrically insulative ceramic material is most likely to be used to reduce risks of compromising the ICCP process. Another purpose of the ceramic material is typically that of environmental sealing. That is, when the ICCP assembly is properly installed upon a structure, the assembly, and specifically the ceramic material, seals the typical environment of the interior of the structure from the exterior; the environmental differences typically being that the structure contains a fluid, often under a pressure greater than normal atmosphere, and that outside of the structure exists typically a normal atmosphere at a normal atmospheric pressure. Therefore it is desired that the ceramic material is able to either sufficiently wet and adhere to the other elements of the assembly wherein sealing occurs, or it is placed enough in compression and its tolerances and surface topology so close-fitting, that sufficient sealing occurs, and thereby an environment seal is attained. An environmental seal is not a requirement of this element of the assembly, as it can later be filled with another element such as an elastomer to provide the environmental seal, but it is preferred. This ceramic material, generally in a solid state of matter during installation and use of the assemblage, will also typically serve the purpose of fixturing the elements of the assemblage to each other by one or both of “wetting” and adhesion, and/or by the compression of outer elements upon the inner, thereby making an assemblage that is generally installed and used as a singular item. It can be stated with confidence that no more than 0.025 milliliters of water should escape through the assembly at 95 PSI at a temperature of 140 degrees fahrenheit per hour; furthermore it is desirable that under those conditions that no water escapes through the seal.
The “electrically conductive element” of the assembly is a material which is generally electrically conductive to an extent that is sufficient for normal application of an ICCP device (which may depend on structure size, electrolyte type, and material composition of both). This material is typically a metal or metal alloy that is greater than 30% of any one of the following metals: titanium, platinum, iridium, iron, or nickel. This element is preferably a metal that has been coated, in whole or in part, with metal oxides or a metal which act to prolong its life when in contact with an electrolyte and/or while discharging an electrical current into the electrolyte, or which act to allow increased bond strength with the ceramic element during production (during fusion by heat). The material which comprises the electrically conductive element can potentially be comprised of an electrically-conducting glass or ceramic or metal-glass composite, such as common in the industry of creating “spark plugs” for use in internal combustion engines. It can also be comprised of carbon or graphite, or iron, or others, many of which have been utilized either as electrical conductors or for use in application of ICCP. Generally, in the scope of this invention, it is preferred that this element be of a composition that has a low rate of thermal expansion, good hydrolysis resistance, and of sufficient strength to function as an electrical connection. Most preferably, this element will be comprised of titanium, or of titanium that has been coated with mixed metal oxides, or of titanium with other metal coating which promote bonding to the oxide elements of the assembly during heat and fusion. The primary utility of this electrically conductive element of the assembly is to transfer electrical current from one side of the assemblage to the other, i.e., when the assemblage is installed on a structure such as a tank: to transfer electrical current from the outside of the structure to the inside, and, in conjunction with the other elements of the assembly, to do so without transfer of fluid, gas, or pressure between the interior and exterior of the structure to which it is fastened. This element may be used directly to connect to an external power source, or there may be additional electrically conductive components that are fastened to it to provide the electrical connection. This element may itself function not only as an environment-isolating electrical conduit, but also as the discharging electrode of the assembly, whereupon it discharges electrical current to the electrolyte directly. It is expected in many cases however, that a separate electrically conductive “electrode” will be attached to it, thereby this element mainly serves as a conduit for electrical current but not as the electrode which discharges electrical current to the electrolyte. This element can potentially be comprised of titanium, platinum, tungsten, or various nickel-cobalt or nickel-iron ferrous alloys such as Kovar, or Invar, depending on expected environment of use, noting that some of these materials must be coated or covered with an electrically insulative barrier if exposed to an electrolyte so as to reduce corrosion of the material when at a more greatly anodic potential than the electrolyte.
The following examples are submitted to illustrate but not to limit this invention.
In this embodiment, shown in
The assembly of a preferred embodiment, first referencing
In the paragraphs below, each of the elements that make up this example of a preferred embodiment are first discussed IN CAPITAL LETTERS AS HEADINGS as singular elements, and after this how they are assembled into an assemblage is discussed.
Referencing
A METAL ELECTRICAL CONDUCTOR (
A CERAMIC MATERIAL (
Not shown in the drawings presented: in some cases an element of the assemblage will be of AN ELECTRICALLY-INSULATIVE COVERING, typically a tube of electrically insulative material which can withstand the final-use environment (typically of a polymer) is (after the assembly has been heated and the ceramic material fused and then cooled) placed over the portion of the rod (
Referencing
First referencing
This possible use description is not intended to limit the extent of claims of this patent. The assemblage, including its discharging electrode element, will typically be inserted into a threaded fitting opening of a tank, with the electrode first being inserted, and the assembly fastened through the use of threads on the exterior portion of the assembly, typically turned by mechanical interference of a shape on the top portion of the assemblage such as a hex. It may be preferable to use a thread sealant on any threads prior to installation to aid in sealing any gasses and fluids in the structure from the environment outside of the structure. The assembly is then typically connected to the positive (anode) output of a DC power source via a connection terminal on the assembly that is exterior to the structure which then brings the current through the assembly to the interior of the structure. Most typically the electrical connections type will be of a flag or spade terminal, or a bolt and eyelet, or a barrel connector, or any number of cost-effective electrical connections available. The structure areas that are intended to have corrosion controlled by the impressed current are connected to the negative (cathode) portion of the electrical power supply.
An alternative to installing the assembly directly to the structure intended for ICCP protection is to make a miniaturized version of the assembly so as to reduce use of the quantity of ceramic material used in the assembly. This miniaturized assembly is then installed into a lower-cost mass-produced fitting which is then installed upon the structure intended for ICCP protection. In this way, the intent of this patent application is not obviated as the additional component serves only as an intermediary, and the intent of utilizing ceramic material to create an ICCP device is still apparent.
This possible use of operation is not intended to limit the extent of claims of this patent. The installed assembly will allow conduction of an electrical current from one side of the assembly to the other side, the assembly being mounted upon a structure, while simultaneously preventing substantive transfer of one or more of the structure's environment-including fluids, pressure differential, or gasses; furthermore, the installed assembly will provide this same environment isolation regardless of connection to electrical power supply, or active or inactive flow of electrical current. Yet environment isolation is not a requirement of this proposed invention, but can be a result of it, and in most cases is a desired attribute. The structure may be a tank, a boat, or other type structure where an electrolyte exists in a partially or fully isolated condition in contact with the structure whilst an environment different from the electrolyte exists also in contact with the structure but such that it is desired that some aspect of the two environments be kept separate. An example of partial isolation might be a boat, wherein there is a structure that keeps water out of the boat so long as the boat is floating, but does allow pressure and atmosphere to exchange as it might given natural circumstances; in this same example, if a small boat were placed inside a tank, and the entire tank pressurized with water, the boat structure may no longer function to isolate environments as originally intended. An example of a tank as the structure indicates that the tank may hold a fluid under pressure and temperature within its structure, and thereby keep the fluid and pressure within it separate and isolated from the environment found on the exterior of the tank; so then in this example, the application of an ICCP assemblage to this tank would imply retaining this environment isolation while also conducting an electrical current to the fluid within the tank.
