WO2018218110A1

WO2018218110A1 - Water tank with antimicrobial internal liner

Info

Publication number: WO2018218110A1
Application number: PCT/US2018/034574
Authority: WO
Inventors: Alexander GOUDAS; Christopher A. Van Haaren; Christopher Kampf
Original assignee: Amtrol Licensing Inc.
Priority date: 2017-05-26
Filing date: 2018-05-25
Publication date: 2018-11-29
Also published as: EP3629739A1; US20180339851A1

Abstract

One or more techniques and/or systems are disclosed for a tank assembly that provides antimicrobial protection to inhibit microbial growth in the interior of the tank body. The tank assembly can comprise a body with a side wall and one or more end walls. An antimicrobial liner can be disposed in the interior of the tank body to cover interior surfaces of the side wall and end wall(s). The antimicrobial liner can comprise an effective amount of an antimicrobial agent to inhibit growth of microbes in the interior of the tank body. In this way, the operation life of the tank assembly may be improved, and problems associated with biofilm fouling may be mitigated.

Description

WATER TANK WITH ANTIMICROBIAL INTERNAL LINER

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 62/511,491, entitled ANTIMICROBIAL TANK LINER, filed May 26, 2017, which is incorporated herein by reference.

BACKGROUND

[0001] Bacteria and other microbes can grow in water containers, which may result in serious health concerns for users of such water. Containers that may hold water can include water towers, water storage tanks, pressure tanks, swimming pools, evaporative condensers, cooling towers, nebulizers, humidifiers, ornamental fountains, and whirlpool spas, to name a few. Water storage tanks and pressure tanks, vessels used to store, deliver, or otherwise transport water, are often used in commercial buildings, industrial locations, residential buildings, and other areas where potable and/or heated water is desirable for use by occupants.

SUMMARY

[0002] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key factors or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0003] One or more techniques and systems described herein can be utilized to provide a tank assembly with an antimicrobial liner, which may inhibit growth of microbes in the interior of a tank body, such as during use for water storage. As an example, the liner may cover portions of the interior surfaces of the tank that may be exposed to water during storage and other use. In this example, the antimicrobial liner may inhibit microbe propagation, which may improve operational life of the tank assembly, and provide improved operational performance during it life. [0004] In one implementation a tank assembly can comprise a body that comprises a sidewall and a first end wall. Further, in this implementation, the tank assembly can comprise an antimicrobial liner that comprises an effective amount of an antimicrobial agent to inhibit growth of microorganisms. Additionally, in this implementation, the antimicrobial liner can cover an interior surface of the sidewall and an interior surface of the first end wall.

[0005] To the accomplishment of the foregoing and related ends, the following description and annexed drawings set forth certain illustrative aspects and implementations. These are indicative of but a few of the various ways in which one or more aspects may be employed. Other aspects, advantages and novel features of the disclosure will become apparent from the following detailed description when considered in conjunction with the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIGURE 1 is a component diagram illustrating an example embodiment of a tank assembly, where one or more techniques and/or one or more systems described herein may be implemented.

[0007] FIGURE 2 is a component diagram illustrating another example embodiment of a tank assembly, where one or more techniques and/or one or more systems described herein may be implemented.

[0008] FIGURE 3 is a flow diagram illustrating an example implementation where one or more portions of one or more techniques described herein may be implemented.

[0009] FIGURE 4 is a flow diagram illustrating an example implementation where one or more portions of one or more techniques described herein may be implemented.

[0010] FIGURE 5 is a flow diagram illustrating an example method for manufacturing a tank assembly, where one or more portions of one or more techniques described herein may be implemented.

[0011] FIGURE 6 is a flow diagram illustrating an example implementation where one or more portions of one or more techniques described herein may be implemented. DETAILED DESCRIPTION

[0012] The claimed subject matter is now described with reference to the drawings, wherein like reference numerals are generally used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. It may be evident, however, that the claimed subject matter may be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to facilitate describing the claimed subject matter.

[0013] In one aspect, a tank assembly can be devised that comprises an antimicrobial liner in at least a portion of the internal chamber of the tank. In this aspect, for example, liquids contained in the interior chamber of the tank assembly can be exposed to the antimicrobial liner, which may mitigate propagation of microbes in the internal chamber. In this way, for example, mitigation of the buildup of microbes that could foul the desired operation of the tank assembly is performed. That is, a buildup of microbes can result in advanced deterioration of portions of the tank assembly, and/or may create masses that clog and reduce performance of the tank assembly. Therefore, in one implementation, the presence of the antimicrobial liner may improve the operational life and performance of the tank assembly. It is to be appreciated that the tank assembly can be, but is not limited to, use with a well system, potable water supply system, heated water system, expansion tank system, cistern storage system, retention tank system, or other commercial and residential water supply, storage and retention systems, among others.

[0014] In one implementation, in this aspect, a tank assembly can comprise a body that comprises a sidewall and a first end wall. Further, in this implementation, the tank assembly can comprise an antimicrobial liner that comprises an effective amount of an antimicrobial agent, effective to inhibit growth of microorganisms. Additionally, the antimicrobial liner is disposed in the tank assembly to cover an interior surface of the sidewall and an interior surface of the first end wall. [0015] In one implementation, the effective amount of the antimicrobial agent in the antimicrobial liner can be in the range of 0.5% to 12% by weight of the antimicrobial liner. In one implementation, the effective amount of the antimicrobial agent in the antimicrobial liner can be in the range of 1% to 10% by weight of the antimicrobial liner. In one implementation, the effective amount of the antimicrobial agent in the antimicrobial liner can be in the range of 2% to 8%) by weight of the antimicrobial liner. In one implementation, the effective amount of the antimicrobial agent in the antimicrobial liner can be in the range of 3% to 7% by weight of the antimicrobial liner. In one implementation, the effective amount of the antimicrobial agent in the antimicrobial liner can be in the range of 4% to 6% by weight of the antimicrobial liner. In one implementation, the effective amount of the antimicrobial agent in the antimicrobial liner can be in the range of 2% to 4% by weight of the antimicrobial liner. It is to be appreciated that the effective amount of antimicrobial agent in the antimicrobial liner can be selected with sound engineering judgment without departing from the intended scope of coverage of the

embodiments of the subject innovation.

[0016] In one implementation, the antimicrobial agent can comprise a silver-based agent. As an example, a silver ion compound (e.g., comprising silver salts) may be utilized to act as the antimicrobial agent. For example, silver salts can release silver ions, which are known to have an antimicrobial effect by disrupting the propagation of microbes, such as bacteria, algae, and other microbes. Other effective antimicrobial agents may be employed in the liner to provide a desired antimicrobial effect. As an example, an effective amount can be any amount of the antimicrobial agent that can inhibit growth of microorganisms in the presence of water in the tank assembly. Advantageously, some implementation described herein provide an antimicrobial liner having an effective amount of an antimicrobial agent within standard regulatory safety limits, and can be at an amount which does not negatively impact the mechanical properties of the liner and the assembly.

[0017] In one implementation, the antimicrobial liner can comprise a polymer-based material. As one example of a polymer-based material, polypropylene may be used in the liner. Other suitable polymers may be selected for use in the liner, selected based on sound engineering principles. As an example, several types of thermoplastics can be used, such as: acrylic, ABS, nylon, polylactic acid, polybenzimidazole, polycarbonate, polyether sulfone, polyoxymethylene, polyetherether ketone, polyetherimide, polyethylene, polyphenylene oxide, polyphenylene sulfide, polystyrene, polyvinyl chloride, and Teflon. Further, several types of thermosetting plastics may be used, such as: various resins, rubbers, epoxy resins, silicone, polyesters resin, and others. In this implementation, the polymer-based material may be used to produce a solid liner applied to or inserted into the inner surface of the tank; or the polymer-based material may be used to produce a liquid-type product applied to the inner surface of the tank and cured.

[0018] In one implementation, the polymer-based material can comprise a plastic that is capable of withstanding temperatures near freezing, up to at least 212° F, and/or reduced or elevated pressures, without loss of preferred characteristics, such as by substantially maintaining its shape, condition and position. For example, the tank assembly may be utilized in a hot water system, a chilled water system, or a pressurized water system, and may be subjected to reduced or elevated temperatures, and/or pressures.

[0019] In one implementation, the antimicrobial liner may comprise a polymer-based sheet that is formed to fit the internal shape of the body. That is, for example, the polymer-based sheet can be formed by any suitable technique known to the art; such as, vacuum forming, injection molding, etc. In this implementation, the resulting formed sheet can be inserted into the tank to cover at least an interior surface of the sidewall and an interior surface of the first end wall. In another implementation, the antimicrobial liner may comprise a coating that is applied to the interior surface of the tank and cured, providing a liner that is substantially permanently bonded to the interior surface of the tank. In this implementation, the antimicrobial liner coating can be applied to the interior surface of the tank to cover at least an interior surface of the sidewall and an interior surface of the first end wall.

[0020] In one implementation, the tank assembly can comprise a first portion comprising the first end wall, and a second portion comprising a second end wall of the body of the tank assembly. In one implementation, the first and second portions may be divided by a flexible membrane, such as a bladder. As an exemplary implementation, the first portion may be configured to receive (e.g., and hold, and release) liquid, such as water; and the second portion may be configured to receive (e.g., and hold, and release) gas, such as air. As an example, the tank assembly can comprise a pressure tank, like those used in well water systems (e.g., and other type of water systems), where pressurized air acting on the bladder is utilized to create pressure on the water in order to generate water pressure for use by occupants. In this implementation, the antimicrobial liner may merely be disposed in the first portion (e.g., holding the water), covering the interior surface of first end wall and the interior surface of the portion of the side wall in the first portion of the body. In other implementations, such as tanks that hold liquids (e.g., water), the antimicrobial liner may cover a larger area (e.g., or even the entirety) of the interior surface of the tank body. It is to be appreciated that the first portion can be configured to receive and store a first material and the second portion can be configured to receive and store a second material, wherein the first material or the second material can be, but is not limited to being, a solid, a gas, a liquid, a vapor, a portion of air, a mixture of water and a cleaning agent, a portion of sanitizing agent, a purifying agent, a C0₂, a water, a portion of sewage, a combination thereof, among others.

[0021] In one implementation, the flexible membrane can comprise an antimicrobial agent, such as one or more of those described above. In this implementation, for example, one or more microbial agents can be integrated into the material used to construct the membrane, such as in the concentrations described herein. In this way, for example, the membrane may also provide for mitigation of microbial growth in the interior of that tank. In one implementation, the antimicrobial agent can be incorporated merely at the surface of the membrane that is exposed to stored water. That is, as an example, the first portion of the tank body can be used to store water, and the membrane surface exposed to the interior of the first portion may comprise and effective amount of antimicrobial agent. Further, as an example, the membrane can be constructed to comprise a smooth surface that may help to mitigate propagation of microbes. Additionally, in one implementation, the membrane can comprise a blue color that may indicate an amount of agent present, and may be used to emit blue light to help inhibit microbial growth.

[0022] In one implementation, the first end wall of the tank body can comprise an orifice that is formed to allow the flow of water into and/or out of first end wall. That is, for example, water can flow into the interior of the tank through the orifice in the first end wall; water can be stored in the interior of the tank body, and water can flow out of the interior of the tank body through the orifice in the first end wall. Further, in this implementation, the antimicrobial liner can comprise an orifice that is formed to allow the liner to be aligned with the orifice of the first end wall. That is, for example, the antimicrobial tank liner can cover the first end wall, but have an opening at the orifice to allow liquid (e.g., water) to flow into the interior of the tank body, through the orifice of the first end wall.

[0023] In one implementation, the tank assembly can comprise a flow diverter that is operably disposed at the orifice of the first end wall; and the flow diverter can be configured to circulate fluid in the tank assembly in operation. That is, for example, the flow diverter can direct incoming water flow in a way that provides continued circulation of the water (e.g., around the interior of the tank body) while water is being introduced into the tank. In this way, for example, circulation of the water can mitigate stagnation of water in the tank, which can improve inhibition of microbe growth on interior surfaces. In this implementation, the flow diverter can be disposed at the orifice of the first end wall, and through the orifice of the antimicrobial liner. It is to be appreciated that the flow diverter can be located at a position inside the tank assembly and the position of the flow diverter at the first end wall is not to be limiting.

[0024] In one implementation, the antimicrobial liner can be configured to have a smooth outer finish, facing the interior of the tank body. That is, for example, the face of the liner that comes in contact with the stored water can have a very smooth finish that is configured to mitigate microbial growth. For example, microscopic pitting in a finish can be a nucleation site (e.g., a site of attachment) for microbial growth, giving the microbes a location to land and initiate growth. In this implementation, the interior finish of the antimicrobial liner can be smooth enough to mitigate these nucleation sites, thereby inhibiting microbes from attachment and growth. For example, the smooth finish may be obtained by a combination of the appropriate type of materials chosen to form the liner, and the type of application and finishing. Sound engineering principles can be utilized to select the appropriate materials, application, and finishing to achieve a known result. For example, a microbe may have a characteristic beneficial for growth or nucleation and the antimicrobial surface or composition can be created to eliminate or reduce such beneficial characteristic. [0025] In one implementation, the antimicrobial liner can comprise a color. In one implementation, the color can provide an indicator of the concentration of the antimicrobial agent present in the antimicrobial liner. In this implementation, a darker color can be indicative of a higher concentration of the antimicrobial agent. As one example, the color indicator can be blue; and, the darker the blue can indicate a higher concentration of the antimicrobial agent in the liner. In this example, a light blue can indicate a low concentration (e.g., 2% by weight), and a darker blue can indicate a higher concentration of the antimicrobial agent (e.g., 4%). In one implementation, the blue color may be used in the antimicrobial liner so that merely blue light is emitted from the liner (e.g., reflected, refracted, or collimated). As an example, blue light is known to inhibit microbial growth in some microbes. Additionally, the blue color can be used to improve good will of user of the tank assembly, for example, as blue color is often associated with clean water. It is to be appreciate that the blue color can be, but is not limited to, light blue, dark blue, teal, turquoise, aqua, cerulean, sea foam, aqua marine, a combination thereof, among others.

[0026] In one implementation, the tank assembly may comprise a valve that is operably disposed in the second end wall. In this implementation, the valve may be configured to allow air (e.g., under pressure) to be introduced into the second portion of the tank body. As an example, for embodiments associated with a water pressure tank, the valve can be used to pressurize the second portion, by introducing pressurized air, which can force the dividing membrane (e.g., bladder) to apply pressure to the first portion of the tank body. In this way, water disposed in the first portion of the tank body will become pressurized based on the amount of air (e.g., and pressure) introduced through the valve in the second end wall.

[0027] In another aspect, the tank assembly may comprise polymer-based walls, and/or composite material walls. That is, for example, the tank assembly may comprise a

polypropylene tank, such as one that is molded into a tank form, and configured to store liquids such as water. As another example, thank assembly can comprise composite material tank that is molded into a tank form, for example, comprising fiberglass and/or carbon fiber or a graphite- based composite. In this aspect, the antimicrobial agent may be incorporated into the material used to construct the tank, for example, instead of (or including) a separate antimicrobial liner. [0028] In one implementation, in this aspect, the tank assembly can comprise a side wall and one or more end walls, composed of a polymer-based material, such as one or more of those described above. For example, a polymer-based material can be constructed into a tank form using blow-molding, roto-molding, 3D printing, injection molding, therm of orming, extrusion and stamping, and other well-known techniques for forming polymer tank forms. In this implementation, an antimicrobial agent can be added to the base material used to create the tank form, resulting in the antimicrobial agent being disposed at an inner surface of the tank body. As another example, the another example, the antimicrobial agent can be added as a layer to the internal surface of the polymer tank body.

[0029] In another implementation, in this aspect, the tank assembly can comprise a side wall and one more end walls composed of a composite material, such as fiberglass, carbon fiber, graphite-base material. For example, a composite material can be used to create a tank form using well-known composite forming techniques; and, two or more of the materials may be used in combination to form the tank body. In this implementation, the an antimicrobial agent can be added to the base composite material, and/or the resin/binder material, used to create the tank form, resulting in the antimicrobial agent being disposed at an inner surface of the tank body. As another example, the another example, the antimicrobial agent can be added as a layer to the internal surface of the composite tank body.

[0030] The following are descriptions of several exemplary implementations, along with illustrative example described in the FIGURES, in furtherance of the details described above. It should be noted that these examples are used to demonstrate one or more aspects of the inventive concept, and should not be construed to limiting the inventive concept in any way.

[0031] While embodiments herein are described in the context of a well tank, the

antimicrobial liners shown and described herein can also be used in other tank assemblies, such as an expansion tank or a retention tank.

[0032] As used herein, masterbatch may refer to a solid or liquid additive for plastic or a coating used for imparting certain properties and/or characteristics to plastics or coating (e.g., antimicrobial properties, color, etc.). [0033] As used herein, Let Down Ratio (LDR) may refer to the level at which a masterbatch is incorporated into a base resin, polymer, or coating compound. For example, an LDR of 4% refers to a composition having 96% polymer and 4% masterbatch.

[0034] Referring now to the drawings, FIGURE 1 depicts an exemplary tank assembly in which an antimicrobial liner can be incorporated. FIGURE 1 shows a tank assembly 100 (e.g., a well tank), designed for use in conjunction with a well pump or the like, and can help to enhance and deliver a relatively consistent pressurized water supply to occupants of a home or commercial property.

[0035] In this implementation, the tank assembly 100 can include a high strength steel sealed outer shell 102 (e.g., the side wall) with an inlet/outlet port 104 (e.g., the orifice in the first end wall) located at the base of the shell (e.g., the first end wall), and an upper air valve 106 (e.g., the valve in the second end wall). The interior of the shell can be divided into two chambers (e.g., the fist portion and the second portion). The upper chamber 108 can contain pressurized air. The lower chamber 110 can contain a tank liner 112 (e.g., a polypropylene liner), which stores potable water. The upper chamber 108 and lower chamber 110 can be separated by a diaphragm 114 (e.g., the flexible membrane, or bladder) which can provides a diaphragm seal 116, and can be used to pressurize the lower chamber 110 as a function of the air pressure in the upper chamber 108.

[0036] In operation, for example, the well tank assembly 100 can be integrated with a well pump which is triggered by a switch to pump water into the lower chamber 110 through the inlet/outlet port 104 when the air pressure falls to a lower threshold pressure (e.g., which corresponds to a low level of water). The pump will stop when the system reaches a preset upper air pressure. When water is demanded by the system's plumbing, the air pressure in the upper chamber 108 transmits a force through the diaphragm 114 against the water in the lower chamber 110, pushing the water into the plumbing system through the inlet/outlet port 104. Once the water is consumed and the pressure reduces, a new cycle begins. The inlet/outlet member 104 of the tank assembly 100 is configured such that water either moves into the system through the inlet/outlet 104 when the pump is engaged, or moves out of the system through the inlet/outlet 104 when there is demand. [0037] FIGURE 2 illustrates an exploded view of one implementation of a water tank assembly 100, for example, as shown and described in the context of FIGURE 1 above. The upper chamber 108 can include an upper cylindrical body 202 having a side wall 204 and an end wall 206, which is provided with an orifice (not explicitly shown-covered by a cap 208). The lower chamber 110 can include a lower cylindrical body 210 having a side wall 212 and an end wall 214 which is also provided with orifice 216.

[0038] The interior surface of the lower end wall 214 and the lower portion of the lower side wall 212 can be covered by a liquid-impervious antimicrobial liner 218, which may be composed of a polymer-based material that is capable of withstanding elevated or reduced temperatures, and/or elevated and reduced pressures. In one embodiment, the liner can comprise a solid sheet that has been formed and inserted into the lower portion. In this embodiment, the solid sheet liner can be bonded to the interior surface of the lower chamber 110, or may merely be placed in a form fitting disposition in the lower chamber 110. In another implementation, the

antimicrobial liner 218 may be applied to (e.g., sprayed on, painted on, rolled on or otherwise applied) the inner surface of the lower chamber 110. In this implementation, the applied liner can be cured after application, and form a substantially permanent bond with, and covering, the inner surface of the lower chamber 110. As an example, the applied liner can comprise a powder coating, a liquid coating, or a plated coating.

[0039] In embodiments herein, the antimicrobial liner 218 can include an antimicrobial agent at an effective amount, for example, in the range of 1% to 8% by weight of the liner, or in the range of 2% to 4% by weight of the liner. An effective amount is any amount of the

antimicrobial agent that can inhibit growth of microorganisms in the presence of water in the tank, microorganisms such as Escherichia coli, Staphylococcus aureus, and Legionella.

Advantageously, embodiments herein provide an antimicrobial liner having an effective amount of an antimicrobial agent within the regulatory safety limits and at an amount which does not negatively impact the mechanical properties of the liner and the assembly. The antimicrobial agent used in embodiments herein can be a silver-based antimicrobial agent, incorporated into the liner during the process of manufacturing the liner. Notably, the amount of antimicrobial agent used in the liner 218 affects the color of the antimicrobial liner 218. That is, the color of the antimicrobial liner 218 is correlated to the effective amount of the antimicrobial agent such that the color darkens as the effective amount of the antimicrobial agent increases. For example, as the amount of the antimicrobial agent used in the antimicrobial liner 218 increases, the color of the antimicrobial liner 218 changes from lighter shades of blue to darker shades of blue. In embodiments, the blue is a phythalocyanine blue, also known as "thalo blue", as this blue color exhibits a strong color, tictantorial strength, and excellent resistance properties to acid, alkali, solvent, lightfastness and weatherability. Phythalocyanine blues are formulated and added into polymer masterbatches such as those described herein to protect the product. The amount of thalo blue added to the masterbatch can be correlated to the effective amount of antimicrobial agents added such that the color of the liner increases as the effective amount of antimicrobial agent increases. In an embodiment, the blue formulated into the masterbatch can be a separate additive that is not part of the antimicrobial agent. In embodiments herein, the liner comes in contact with potable water, acids, alkali, and solvents that are commonly found in drinking water supplies. The liner formulated with the phythalocyanine blue emits blue light wavelengths having a greater effect on inhibiting bacterial and fungal growth. Advantageously, the combination of the antimicrobial agent with the blue liner provides a greater effect on bacteria efficacy than either alone. Furthermore, a light blue color is used as this color generally improves consumer perception of the quality of taste in a phenomenon known as synesthesia. That is, blue is related to a notion that is described in terms of clean, fresh, and bacteria free.

[0040] The antimicrobial liner 218 described herein can provide for a reduction of biofilm growth which can physically restrict flow paths. Biofilm with anaerobic population may indicate that the growth is advanced as it can be more prevalent in oxygen-depleted areas, which renders areas such as inside a water tank under pressure to greater susceptibility of biofilm growth. The antimicrobial liner 218 can have a great affect in this environment. The antimicrobial agent used in the antimicrobial liner 218 in conjunction with flow diverter, helps reduce biofilm growth by enhancing circulation within the tank to increase bacteria contact with the antibacterial liner surface. Moreover, using the antimicrobial agent in conjunction with a moving diaphragm ensures that bacteria and slime are sloughed off the surface of the liner for biofilm reduction on the liner surface. Biofilm can scale and form with biological material and minerals from deposits in water or adhesion of particles such as sand. Reduction of the biofilm allows the diaphragm to cycle naturally, and also avoids abrasion of the diaphragm and avoids creating abrasive surfaces thereby improving the lifespan of the diaphragm. Furthermore, the antibacterial liner 218 provides for reduction of corrosion in the tank and vicinity by maintaining clean bacteria-free surfaces, as bacteria can affect iron and stainless steel surfaces to a point where the surfaces are susceptible to pitting corrosion. The surface of the antibacterial liner 218 is made to be smooth so as to make it harder to for bacteria to grow, as rough surfaces are easier for slime to form and for bacteria to grow.

[0041] The antimicrobial liner 218 can be manufactured by any suitable technique known to the art; such as, vacuum forming, injection molding, etc. Exemplary methods of producing the antimicrobial liner 218 will be further delineated below in the context of FIGS. 3 and 4.

[0042] The antimicrobial liner 218 is configured to cover an interior surface of the sidewall 212 and an interior surface of the end wall 214. The antimicrobial liner 218 is formed with an orifice 302 which mates with orifice 216 in end wall 214 of lower cylindrical body 210. The portion of liner 218 adjacent the orifice 302 is clamped to lower end wall 214, welded, brazed or otherwise suitably connected to tank assembly 100 and adapted to connect tank assembly 100 with the water system of which it forms a part. The orifice 216 and orifice 302 are configured to be aligned with inlet/outlet 104 of FIGURE 1 for entry and exit of water in the tank assembly 100.

[0043] Flexible diaphragm 114, formed of butyl rubber or other suitable elastomers, is disposed inside of lower cylindrical body 210 and is adapted to conform to the shape thereof. An exemplary manner in which diaphragm 114 is secured to lower cylindrical body 210 can be found in U.S. Patent No. 5,386,925. Such features and content disclosed in U.S. Patent No. 5,386,925 are incorporated herein by reference

[0044] When installed, well tank assembly 100 is supported on stand 304. Stand 304 has a cylindrical side wall 306 which allows fitting 308 to extend below end wall 214 of the lower cylindrical body 210. Side wall 306 includes a cutout 310 for allowing the water supply/return line 88 to extend from the fitting 308 to the exterior of the tank assembly 100. In another embodiment, the tank assembly 100 can be supported from a ceiling, wherein a portion of a plumbing system or a bracket can attach to at least one of the upper cylindrical body 202 or the lower cylindrical body 210.

[0045] A flow diverter insert 312 is positioned at least partially within orifice 314 of fitting 308. The orifice 314 is configured to be aligned with orifice 302 of liner 218 and orifice 216 of lower end wall 214. The flow diverter insert 312 is configured to circulate water within the tank and is further described in U.S. Patent No. 9,004, 102. Such features and content disclosed in U.S. Patent No. 9,004, 102 are incorporated herein by reference.

[0046] FIGURE 3 shows an exemplary method of manufacturing the antimicrobial liner 218 for use in the well tank assembly 100 shown and described above in the context of FIGS. 1 and 2. As shown, masterbatch 304 includes an antimicrobial additive 302 that can be incorporated with plastic resins during molding and provide a biocide treatment to control microorganisms. Regrind 306 can include scraps of antimicrobial resin masterbatch liners. The masterbatch 304 and regrind 306 are processed together in a mixer, such as a hopper 306 to form an antimicrobial resin composition to be used in making the antimicrobial liners described herein. The masterbatch 304 can be present at 50% or more by weight of the composition, and the regrind can be present at 50% or less by weight of the composition. The composition is then extruded through an extruder 308 and provided to a vacuum former 310. The antimicrobial liner 312 is formed, for example, by process of vacuuming forming. The scraps 314 left from the process of producing the liner 312 is treated as regrind 316 to be used in as regrind 306 in another process to manufacture the antimicrobial liner. While the process shown and described in FIGURE 3 uses vacuum forming to produce the antimicrobial liner 312, other suitable processes such as injection molding may be used in other embodiments.

[0047] FIGURE 4 shows another method of manufacturing the antimicrobial liner 218 for use in the well tank assembly 100 shown and described above in the context of FIGS. 1 and 2. Masterbatch 404 can include an antimicrobial agent 402, for example, a silver based

antimicrobial agent (e.g., silver ions). As shown, the masterbatch includes a LDR of 4%, but the antimicrobial gent 404 can be present in the masterbatch at 1% to 8% by weight of the composition, and can be present at 2% to 4% by weight of the composition. The virgin material 406, which does not include an antimicrobial additive, can include a base resin 404, such as polypropylene or other suitable plastics. The virgin material 406 can be present in the composition at greater than or equal to 50% by weight of the composition. Regrind 408 can include regrinds 414 and 416, and the regrind 408 can be present in the composition at 46% or less by weight of the composition. The masterbatch 404, virgin material 406 and regrind 408 are processed in a mixer, such as hopper 420, to form an antimicrobial composition for use in making the antimicrobial liner described herein. The composition is then extruded through an extruder 422 and provided to a vacuum former 424. The antimicrobial liner 412 is formed, for example, by process of vacuuming forming. Scrap 418 is scrap from processing of the virgin material 406. Scrap 426 is scrap from processing of the masterbatch 404 material, which contains antimicrobial agents. The scraps 418 and 426 left from the process of producing the liner 412 is then treated as regrinds 414 and 416, respectively, to be used in as regrind 408 in another process to manufacture the antimicrobial liner. While the process shown and described in FIGURE 4 uses vacuum forming to produce the antimicrobial liner 412, other suitable processes such as injection molding may be used in other embodiments.

[0048] Advantageously, the antimicrobial liners described above show an ability to reduce the growth of common fungus, algae, & bacteria. Furthermore, taste and odor results revealed that the antimicrobial agent in the liners was undetectable.

[0049] For example, an antimicrobial liner produced according to the methods described herein with a 4% LDR repeatedly performed up to log 1 efficacy reduction against legionella, and antimicrobial efficacy against both E. coli and S. aureus as their activity values exceeded the standard value of log 2, which means this application has a greater than 99% bacterial reduction rate. When bacteria contact the surface of the antibacterial liner, reactions with the silver ion rendered the bacteria inert, which are then swept away during tank usage. This demonstrated its ability to be an effective antimicrobial solution against common microorganisms and legionella. The benefit of having such an antibacterial liner ensures that even if a water system has a problem with bacteria, the tank will be protected and will not further propagate the issue.

[0050] In one aspect, a method of manufacture can be devised for manufacturing a tank assembly. In this aspect, the tank assembly can be manufactured with an antimicrobial liner, and used to inhibit growth of microbes in the interior of the tank assembly. In this way, for example, the operational life of the tank assembly can be increased, and potential operation problems associated with fouling due to microbes can be mitigated.

[0051] FIGURE 5 is a flow diagram illustrating an exemplary method 500 for manufacturing a tank assembly. The exemplary method 500 begins at 502. At 504, a tank body comprising a side wall and a first end wall is constructed. At 506, an antimicrobial liner is installed in the tank body so that the antimicrobial liner covers an interior surface of the sidewall and an interior surface of the first end wall. At 508, the antimicrobial liner comprises an effective amount of an antimicrobial agent to inhibit growth of microorganisms. Having installed the antimicrobial liner in the tank body, the exemplary method 500 ends at 510.

[0052] FIGURE 6 illustrates another implementation of an example method 600 for manufacturing a tank assembly. The example method 600 begins at 602. At 604, the tank body comprising a side wall and a first end wall can be constructed. At 606, the antimicrobial liner can be constructed. Constructing the antimicrobial liner can comprise, at 608, mixing the effective amount of antimicrobial agent with a polymer resulting in a antimicrobial agent and polymer mix. The effective amount of the agent can comprise agent in the range of 0.5% to 12% by weight of the antimicrobial liner. Further, at 610, constructing the antimicrobial liner can comprise heating the mix resulting in a heated mix. At 612, the heated mix can be formed into a sheet; and at 614, the sheet can be formed into a shape that will cover the side wall and first end wall of the interior of the tank body. At 616, the antimicrobial liner can be installed in the tank body to cover the interior surface of the sidewall and an interior surface of the first end wall. Having installed the liner in the tank body, the example method 600 ends at 618.

[0053] In an embodiment, the antimicrobial liner can be a paint coating. For instance, the paint can be an additive within the paint to provide antimicrobial features for the liner or an inside of a tank assembly. The additive can be further included with epoxy. For instance, the polypropylene can be based with antimicrobial liner versus epoxy base used for the paint on protection. In another embodiment, the antimicrobial can be used with aerosol. In another embodiment, the antimicrobial can be a molded liner or a paint with antimicrobial agent added, wherein the paint can further be aerosol. For instance, the antimicrobial agent can be done with an aerosol technique to be sprayed onto a material. In another embodiment, the antimicrobial agent can be mixed into the internal paint (e.g., such an epoxy). The antimicrobial agent (e.g., additive to paint or incorporated into a liner) protects the product by preventing growth while not treating water. In another embodiment, the antimicrobial agent prevents growth while also treating water.

[0054] In another embodiment, the blue pigment can be mixed with epoxy to coat an interior of a tank assembly. In another embodiment, a top layer of a multi-layer air cell can include the antimicrobial liner or agent. In another embodiment, a high density polypropylene tank or bottle in indirect fired hot water storage can include the antimicrobial liner or agent.

[0055] Moreover, the word "exemplary" is used herein to mean serving as an example, instance or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless specified otherwise, or clear from context, "X employs A or B" is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then "X employs A or B" is satisfied under any of the foregoing instances. Further, At least one of A and B and/or the like generally means A or B or both A and B. In addition, the articles "a" and "an" as used in this application and the appended claims may generally be construed to mean "one or more" unless specified otherwise or clear from context to be directed to a singular form.

[0056] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above.

Rather, the specific features, ranges, and acts described above are disclosed as example forms of implementing the claims.

[0057] Also, although the disclosure has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. The disclosure includes all such modifications and alterations and is limited only by the scope of the following claims. In particular regard to the various functions performed by the above described components (e.g., elements, resources, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the disclosure. In addition, while a particular feature of the disclosure may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms "includes," "having," "has," "with," or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprising."

[0058] The implementations have been described, hereinabove. It will be apparent to those skilled in the art that the above methods and apparatuses may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof.

Claims

What is claimed is:

1. A tank assembly, comprising:

a body comprising a sidewall and a first end wall; and

an antimicrobial liner comprising an effective amount of an antimicrobial agent to inhibit growth of microorganisms;

wherein the antimicrobial liner covers an interior surface of the sidewall and an interior surface of the first end wall.

2. The tank assembly of claim 1, the effective amount of the antimicrobial agent is in the range of 0.5% to 12% by weight of the antimicrobial liner.

3. The tank assembly of claim 2, the antimicrobial agent comprising a silver based antimicrobial agent.

4. The tank assembly of claim 1, the first end wall comprising an orifice formed to allow flow of fluid into and/or from the body.

5. The tank assembly of claim 4, the antimicrobial liner comprising an orifice formed to allow alignment with the orifice of the first end wall.

6. The tank assembly of claim 4, comprising a flow diverter operably disposed at the orifice of the first end wall and configured to circulate fluid in the tank assembly.

7. The tank assembly of claim 1, the body comprising a first portion, comprising the first end wall, and a second portion, comprising a second end wall of the body.

8. The tank assembly of claim 7, the antimicrobial liner merely covering the interior surface of the sidewall in the first portion.

9. The tank assembly of claim 7, the first portion configured to receive water and the second portion configured to receive air, the first and second portions divided by a flexible bladder.

10. The tank assembly of claim 1, the antimicrobial liner comprising a substantially smooth outer finish facing internally in the tank to mitigate microbial growth.

11. The tank assembly of claim 1, the antimicrobial liner comprising a blue color, the blue color providing an indicator of concentration of the antimicrobial agent present in the

antimicrobial liner, wherein a darker blue color is indicative of a higher concentration.

12. A method of manufacturing a tank assembly

constructing a tank body comprising a side wall and a first end wall; and

installing an antimicrobial liner in the tank body so that the antimicrobial liner covers an interior surface of the sidewall and an interior surface of the first end wall;

wherein the antimicrobial liner comprises an effective amount of an antimicrobial agent to inhibit growth of microorganisms.

13. The method of claim 12, comprising constructing the antimicrobial liner with the effective amount of the antimicrobial agent, comprising adding an amount of the antimicrobial agent in the range of 0.5% to 12% by weight of the antimicrobial liner.

14. The method of claim 12, the antimicrobial agent comprising a silver-based agent in liquid or solid form.

15. The method of claim 12, constructing the antimicrobial liner comprising forming a polymer-based sheet in the shape of the interior surface of the sidewall and the interior surface of the first end wall.