Drug – bio-affecting and body treating compositions – Inorganic active ingredient containing – Heavy metal or compound thereof
Reexamination Certificate
1999-07-08
2001-07-03
Clardy, S. Mark (Department: 1616)
Drug, bio-affecting and body treating compositions
Inorganic active ingredient containing
Heavy metal or compound thereof
C424S682000, C210S748080, C210S749000, C210S764000
Reexamination Certificate
active
06254894
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to compositions and methods for treating water, and in particular, compositions containing silver and a material such as aluminum or zinc.
2. Description of the Related Art
In many situations, water is purified to remove microorganisms, such as bacteria or algae, and harmful metal ions, such as mercury, lead and copper. Water purification may be accomplished by filtration, providing water suitable for consumption or for use in recirculating systems such as swimming pools, hot tubs, spas and cooling towers. Water purification may also be accomplished by adding chemicals like chlorine or bromine. However, it has been found that not only does chlorine have an objectionable odor, but that it can also cause skin irritations and serious eye irritations to bathers in pools or spas.
Because of the objectionable physical properties of chlorine a number of alternate water treatment systems which operate without chlorine have been developed in recent years. One of the most effective types of alternative water treatment systems is a system in which silver ions are added to water to kill microorganisms therein. However, it has been found that in many cases systems of this type are only partially effective due to insufficient control of the silver ion levels, which should be maintained between about 0.01 ppm and about 0.1 ppm. Failure to maintain this ion level concentration may result in staining or health problems.
Accordingly, a water purification composition that provides better control of the silver ion levels will provide an improvement over conventional silver-containing water purification compositions by avoiding or reducing the effect of disadvantages as noted above.
SUMMARY OF THE INVENTION
In one aspect, the invention features a water purification composition including silver and aluminum metal. The silver may be present as metallic silver or silver compounds, such as soluble or sparingly soluble silver salts. These salts can include silver nitrate or silver chloride.
In another aspect, the invention features a water purification composition including silver, and metallic zinc and aluminum. In a particular embodiment of this aspect of the invention, the silver is in metallic form, and in an even more particular embodiment, the zinc and aluminum are present as an alloy. Examples of these alloys include about 2 to about 5 weight percent aluminum, and respectively, about 98 to about 95 weight percent zinc, or alternatively, about 2 to about 5 weight percent zinc, and respectively, about 98 to about 95 weight percent aluminum.
In a further aspect, the invention features a water purification composition including silver as a biocidal element and zinc metal. In addition, the water purification composition may further include aluminum or copper.
In yet another aspect, the invention features a method of purifying water by exposing the water to one or more of the water purification compositions described above. In a particular embodiment, the water purification system provides a concentration of silver in the water desirably between about 0.01 and about 0.1 ppm.
In still another aspect, the invention features a water purification system including silver and aluminum metal and an oxidizing agent or source of an oxidizing agent. The oxidizing agent can be selected from the group consisting of free available chlorine, ozone, and chlorine dioxide. In addition, the source of oxidizing agent can be selected from the group consisting of dipersulfates, monopersulfates, hypochlorite salts, chlorites, peroxides, perchlorates, hypobromites, percarbonates, chlorine dioxide and permanganates.
The water purification composition of the present invention can provide a number of advantages. Because the silver ion concentration in the body of water is controlled by equilibrium reactions, the effectiveness of the composition is not dependent on flow rate. Therefore, there is no need to add filler material to inhibit particle erosion at high flow rates, and a device containing the purification composition can be used directly in high flow conditions, such as in spa filter cores, without requiring modification of the plumbing system to control flow rates through the device.
In addition, the water purification composition of the invention imparts and maintains sufficient amounts of silver ions in water to effectively disinfect the water while reducing the concentration of other undesirable metal ions in the water, but without exceeding the levels of silver that cause staining or health problems.
When the water purification composition of the invention contains silver and zinc metal, the composition releases and maintains a residual concentration of zinc ions which provides algaestatic properties. Furthermore, metallic zinc helps remove hazardous metal ions (e.g., mercury, lead) and metal ions which are known to stain pool and spa surfaces (e.g., iron, copper, manganese) effectively.
When the water purification composition of the invention contains silver and aluminum metal, the aluminum ions released into the water can act as a flocculating agent to aid in the removal of particulates and/or metals. Furthermore, the aluminum metal may be present as an alloy with other metals, such as zinc or copper, that provide other properties to the composition, such as microbiocidal or algaestatic properties. An inorganic oxide, if present, which has a slightly positive, zero, or negative surface charge, also assists in the adsorption of hazardous metal ions.
The water purification composition of the invention does not significantly alter the pH, calcium hardness, or free available chlorine in the water. It can be used in swimming pools and spas where elevated pH reduces the effectiveness of chlorine, calcium hardness must be maintained to prevent corrosion, and chlorine residuals must be maintained for disinfection.
Other advantages and features of the invention will be apparent from the description of specific embodiments of the invention, and from the claims.
DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION
The term “zeta potential” as used herein, means surface charge. The zeta potential of an inorganic oxide can be determined, for example, by measuring electrophoretic mobility.
The phrase “point of zero charge,” as used herein, means the pH at which the surface charge of the inorganic oxide (i.e., zeta potential) is zero.
The term “E
h
,” as used herein, means the reduction potential with respect to the standard hydrogen electrode.
The term “recirculated,” as used herein, means continuous flow of the water to expose the water to the water purification device, for example, in cooling towers, spas, swimming pools, and hot tubs.
In one embodiment, a water purification composition includes silver and a second material, which is desirably a metal. The silver may be in metallic form or present as a compound, such as soluble or sparingly soluble silver salts. Examples of these salts can include silver nitrate and silver chloride. Examples of the second material can include zinc, copper, aluminum, iron, or manganese and can have an E
h
less than about 0.34 V. In a particular aspect of this embodiment, this second material is zinc or aluminum metal. Furthermore, the second material may be homogenous or heterogeneous, e.g., an alloy of two or more metals. A particular heterogeneous material suitable for use in the present invention is an alloy of aluminum and zinc. Examples of these alloys can include about 2 to about 5 weight percent aluminum, and respectively, about 98 to about 95 weight percent zinc, or alternatively, about 2 to about 5 weight percent zinc, and respectively, about 98 to about 95 weight percent aluminum. The second material may be in the form of a powder, shavings, turnings, or larger pieces.
The silver content of the water purification composition is generally any amount that will provide a suitable silver ion concentration in the water when the composition is used. For most applications, a silver content between about 0
Bollinger Mark A.
Denkewicz, Jr. Raymond P.
Grenier Joseph W.
Rafter John D.
Souza Therese R.
Clardy S. Mark
Gray Bruce D.
Kilpatrick & Stockton LLP
Pryor Alton
Russell Dean W.
LandOfFree
Silver self-regulating water purification compositions and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silver self-regulating water purification compositions and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silver self-regulating water purification compositions and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2477132