The present invention provides a water filtration apparatus for mounting on the exposed exterior surfaces of a refrigerator to provide filtered water to the interior of a refrigerator cabinet. The apparatus may be mounted on the exposed or visible surfaces of the refrigerator for ease of installation, monitoring, and filter replacement. A readily replaceable filter cartridge is also provided.

The present invention relates to a water filtration apparatus for mounting on the exposed or visible exterior surfaces of a refrigerator. More specifically, the present invention is an apparatus with a readily replaceable filter cartridge for providing filtered water to the interior of a refrigerator cabinet so that filtered water is available for the refrigerator""s ice maker or chilled water dispenser.
Water intended for human consumption is expected to be either free of harmful constituents or contain concentrations of such constituents that are below harmful levels. To provide potable water for use in homes and businesses, municipalities utilize industrial scale processes in an effort to eliminate or reduce harmful constituents present in water drawn from large, naturally occurring water sources. Potable water is also frequently obtained on a smaller size scale from wells and springs and usually without any treatment prior to consumption.
Unfortunately, the potability of a particular water supply is sometimes questionable. The consistency and efficiency of treatment by municipalities may vary due to numerous factors such as heavy rainfall, equipment failures, and usage levels. Depending upon the seriousness of a variation in treatment, a municipality may be forced to notify its consumers that further treatment of the water supplied, e.g. boiling, is required at the point of use before consumption is safe. Water obtained directly from a natural source may also become suspect depending upon environmental conditions near the source. For examples, wells and springs can be contaminated due to rain water run-off washing a contaminant into the source.
Various water filtration devices have been developed. Such devices range from those located at the point-of-use (e.g. the spigot of a kitchen sink, gravity-flow dispensers such as dispensers, and low-pressure dispensers such as sports bottles) to the generally bulkier point-of-entry units hidden from view within the plumbing of a home or office. Many of these devices use activated charcoal in at least one stage of the filtration process. Activated charcoal helps to remove strong odors and tastes from water. More specifically, activated charcoal can remove chlorine and sediment from water.
Generally, the currently available devices for water filtration on a nonindustrial scale may be divided into two categories: point-of-use and point-of-entry filtration systems. Typically, a point-of-entry system provides for the filtration of water at the point where the supply enters a dwelling or area of use. The point-of-entry system filters the entire water supply, and filtered water is then distributed to various points of use after filtration. As an example, a point-of-entry system may be located in the basement, cellar, or other location hidden from plain view. In contrast to point-of-use systems, point-of-entry systems may be larger in physical size because of the volumetric rate of water that must be filtered in order to supply filtered water to all of the points-of-use within a dwelling or other use area. Furthermore, a point of entry system may be less efficient because water may be filtered unnecessarily. For example, the homeowner may desire filtered water for the kitchen and bathrooms but not for outdoor spigots or laundry.
Point-of-use systems, on the other hand, provide for filtration of the water at the point of consumption or application. For example, point-of-use systems may be located at the kitchen sink ensuring that potable, filtered water is used in cooking and kitchen cleaning. Such systems may consist of a device, visible to the user, attached to the end of a faucet. Other systems may consist of a filter located within a pitcher such that water placed into the top of the pitcher filters water through to a bottom compartment for storage until consumption. Still other systems, due to size and bulkiness, may be located under a sink or within a nearby kitchen cabinet.
Point-of-use water filtration systems for refrigerators have also been developed as automatic ice-makers and chilled water faucets or dispensers are now common features on many of the commercially available models. For those consumers not having point-of-entry systems, the water must be filtered prior to ice formation or water dispensing if unwanted contaminants are to be removed before use. Point-of-use filtration systems for use in conjunction with household refrigerators are varied as described below.
For example, U.S. Pat. No. 5,320,752, issued to Clack et al., describes a water purification system employing a modular flat filter assembly for installation inside a freezer door, beside a kitchen cabinet, or on a countertop. The U-shaped filter housing is charged with a granulated filtration medium such as activated charcoal. The filter housing has a plurality of staggered ribs and protrusions formed in the walls of the housing. These features allegedly provide structural support against water pressure within the filter housing and prevent flow channels from forming in the granulated filtration medium. While the filter assembly is described as flat, the use of granular filter media, staggered ribs, and protrusions add bulk and thickness to the filter assembly. Furthermore, the unit is not intended for mounting on the exterior surfaces of the refrigerator where the filter media may be readily accessed and replaced when necessary. Instead, like other point-of-use water filtration systems used in conjunction with refrigerators, the filtration apparatus is difficult to reach and access without moving the refrigerator or opening the refrigerator/freezer doors.
U.S. Pat. No. 3,982,406, issued to Hanson et al., illustrates a refrigerator water storage dispensing system with water filter. The system includes a water storage tank and a filter cartridge assembly that are installed within the interior of a refrigerator for removing undesired constituents from the chilled water stream immediately prior to being dispensed. The filter media is contained within a cartridge constructed from an elongated hollow cylindrical casing or tube. The filter container is described as having an overall height of 13 inches and is filled with a granular material such as granular activated charcoal. The system occupies a substantial amount of space within the interior of the refrigerator cabinet because it requires a location for both the water tank and the filter cartridge. In addition, the filter cartridge is not readily accessible for replacement of the filter media because the cartridge is located within the interior of the refrigerator cabinet and must be accessed by opening the doors to the refrigerator and relocating any food products that might interfere with such access.
U.S. Pat. No. 4,207,994, issued to Offlee, describes a refrigerator system utilizing assemblies to enable dispensing cold water or ice made from purified water. The system consists of a cabinet located near the refrigerator containing a water tank, pump, and filter that is connected by piping to the refrigerator. Another tank may be located within the refrigerator for water storage. When the water level in the refrigerator tank falls below a certain level, the pump is activated and filtered water is pumped from the cabinet into the tank within the refrigerator. Water in the cabinet tank may be passed through a filter and then to the pump. Alternatively, the cabinet tank may be stocked with water that has already been filtered such that no filter is required for the cabinet. This system requires a substantial amount of space near the refrigerator for locating the cabinet. Unlike the present invention, the filter is not located on the exterior of the refrigerator or the cabinet where filter replacement may be more readily facilitated. In addition, this system requires a pump which must be powered and eventually replaced when worn.
U.S. Pat. No. 4,571,953, issued to Caruso, describes a combined refrigerator and water filtration unit. While the filtering apparatus is not specified, chambers for holding a water filtration apparatus are located within the refrigerator compartment. The chambers are illustrated as two large cylinders located within the compartment. As with the other devices described above, the chambers described in U.S. Pat. No. 4,571,953 are not readily accessible for easily changing the filter media. In addition, the water filtration units appear to occupy a large volume of the refrigerator cabinet.
U.S. Pat. No. 5,135,645, issued to Sklenak et al., is a directed to a refrigerator water filter located in a compartment constructed within the wall of the refrigerator cabinet. A small cover is used to access the filter from the inside compartment of the refrigerator. The filter is illustrated as a cylindrical cartridge. Because of its location within a compartment constructed in the refrigerator wall, the filter media cannot be readily replaced or observed without first opening the refrigerator door and removing or relocating refrigerated items in front of the compartment.
U.S. Pat. Nos. 5,290,442; 5,454,944; and 5,560,393, all issued to Clack, describe a self-contained, purified drinking water refrigerator storage apparatus. A filter assembly is attached to the rear of a water storage container. Means are provided for attaching the apparatus to a faucet. Upon turning on the faucet, water flows through the filter assembly and into the storage container. Once the container is full, the water storage apparatus is disconnected from the faucet and placed into a refrigerator for storage until consumption. As defined, provision must be made for the space occupied by the container and the cylindrically-shaped filter cartridges on the back of the container. Furthermore, replacement of the filter media requires disconnecting tubing from the filter cartridges.
U.S. Pat. Nos. 5,707,518 and 5,715,699, all issued to Coates et al., describe a refrigerator water filter assembly for mounting onto the surfaces of the interior of a refrigerator. The filter cartridge includes a cylindrical filter media located within a housing that is mounted inside the refrigerator. Accordingly, the filter media cannot be replaced or observed without opening the refrigerator door and relocating items near the filter. Additionally, removal of the filter media for replacement requires that a housing be unscrewed and the filter cartridge removed from the housing.
A common deficiency of previous devices for filtering water for refrigerator units is the difficulty of accessibility to the device. Most of the devices discussed above are filtration units that are mounted either inside the refrigerator, inside the refrigerator cabinet shell, or on the rear, unaccessible exterior of the refrigerator. By being mounted in such locations, the filtration units is not easily observable for the purpose of determining when the filter media in the device has reached the end of its useful life. In addition, replacing the filter media is difficult because either the refrigerator doors have to remain open during replacement and stored items must be relocated, or the entire refrigerator must be pulled away from the wall to gain access to the rear exterior. Therefore, there is need for a water filtration apparatus, for use with a refrigerator, that can be readily observed to determine when the filter media is spent and that can be accessed to facilitate filter removal and replacement with a clean filter. Optimally, a need exists for an apparatus that meets these needs while occupying only a minimum amount of space.
The present invention addresses some of the problems identified above by providing a water filtration apparatus for mounting on the exposed exterior surfaces of a refrigerator. A means of mounting the apparatus onto the exterior surfaces is provided. The apparatus also includes a readily replaceable filter cartridge. Due in part to these features, the water filtration apparatus of the present invention results in improved efficiency in replacement time and required space as compared to existing devices. The inventive device also results in an apparatus that is readily observable to determine whether the filter media has reached the end of its useful life.
To enable the filter cartridge to be readily replaceable, the filter cartridge is releasably connectable, without the use of special tools, to a filter receptacle. The filter cartridge contains a material or combination of materials for removing undesired constituents from the unfiltered water. Because of the ease with which the filter cartridge of the present invention may be replaced and further because of its readily accessible location on the exterior of the refrigerator, the volume of filter media required may be reduced, which allows the overall size of the present invention to be smaller than existing devices. The size may also be reduced through the use of a flat water filter media. Available in sheets that are less than xe2x85x9 inches in thickness, flat water filter media may be used within the filter cartridge of the present invention to substantially reduce its overall size as compared to existing refrigerator water filters that employ a granular filter media in filters that are not as easily accessible.
To use the water filtration apparatus of the present invention, the consumer mounts the housing containing the filter cartridge onto the exterior surface of the refrigerator. An unfiltered water supply is connected to the unfiltered water inlet of the present invention. Water from the unfiltered water inlet flows to the filter receptacle and through the filter media. Filtered water exits the filter media and is supplied to the refrigerator through a filtered water outlet that the consumer connects to the interior of the refrigerator cabinet. The refrigerator is thereby supplied with filtered water to produce ice or to provide chilled water from the refrigerator""s water dispenser.
Because the water filtration apparatus of the present invention is mounted on an exposed, easily accessible, and plainly visible surface of the refrigerator cabinet, the consumer may more readily and easily install the present inventive filter cartridge. In addition, an indicator of filter life may be provided with the present invention which is also readily observable because the apparatus is mounted on the exterior of the refrigerator.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the principles of the invention.

Refrigerator-mounted water filtration apparatus


Compositions containing as active ingredients a lipid-soluble benzoquinone, e.g. Coenzyme Q10 and at least one omega-3 polyunsaturated fatty acid selected from eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and linolenic acid (LNA), for the prevention and/or treatment of mitochondriopathies.

This is A371 of PCT/IT99/00331 filed Oct. 19, 1999.
The present invention relates to a pharmaceutical/nutritional composition for supporting and/or providing therapy to individuals at risk and/or under treatment for dysfunctions of energy metabolism, and specifically, for mitochondrial diseases.
More specifically, the present invention relates to a composition comprising (a) an amount of a lipid-soluble benzoquinone selected from the group consisting of ubiquinone (Coenzyme Q10, CoQ10), its reduced form, ubiquinol-10 (CoQ10H2) or mixtures thereof, effective for performing a therapeutical and/or preventive and/or nutritional activity, and (b) at least a further component suitable for stimulating and enhancing the intramitochondrial transportation of component (a), the resulting composition being potently effective for the prevention and/or treatment of mitochondriopathies.
Accordingly the composition may take the form and exert the action of a dietary or nutritional supplement or of an actual medicine, depending upon the support or preventive action, or the strictly therapeutic action, which the composition is intended to exert in relation to the particular individuals it is to be used in. Depending on the actual circumstances, the composition of the present invention need not or, alternatively, should be taken under the supervision of an attending physician.
In the publication by the United Mitochondrial Disease Foundation, xe2x80x9cAbout Mitochondria and Diseasexe2x80x9d (http:/ibiochemgen.ucsd.edu/umdf/AboutMitoDisease.htm), which is incorporated herein by reference, the following definition of what a mitochondrial disease is, and what the triggering, sub-cellular causes are, is given:
xe2x80x9cThe mitochondria produce adenosine triphosphate (ATP), the body""s mobile energy source. When mutations occur which affect the mitochondria, the vital supply of ATP is disrupted, less and less energy is generated within the cell. When this process is repeated on a large scale throughout the body, whole systems begin to fail, and the life of the person in whom this is happening can be compromised, changed or even ended. The cells that require the most energy, like the brain, heart and skeletal muscles, are the most vulnerablexe2x80x9d.
This reference also provides a detailed list and description of mitochondrial diseases, which encompasses, inter alia, Co-enzyme Q10 deficiency; Complex III deficiency (Ubiquinonexe2x80x94cytochrome c oxidoreductase deficiency) whose symptoms include pigmentary retinopathy; Complex IV deficiency/COX deficiency (cytochrome c oxidase deficiency) whose symptoms include optic atrophy and ophthalmoplegia; CPEO (Chronic Progressive External Ophthalmoplegia Syndrome) whose symptoms include visual myopathy and retinis pigmentosa; ARMD (Age-Related Macular Degeneration); NARP (Neuropathy, Ataxia and Retinis pigmentosa) and many others.
Since CoQ10 is indispensable to cellular bionergetics, its deficiency may bring about a host of pathologies.
Indeed, CoQ10 is known to play an essential role as an electron (redox) carrier in the mitochondrial electron transport chain of the cell. However, it also protects membrane phospholipids and those in LDL from peroxidation as well as protects and/or regenerates vitamin E. CoQ10 is synthesized in the body from precursors of cholesterol synthesis and therefore is not classed as a vitamin. However, the ability to synthesize CoQ10 decreases with age and there may be an increasing dependence on food to supply the nutrient. The most abundant sources are fresh unprocessed foods, particularly meats, fish, nuts and seed oils. The average daily intake of CoQ10 is approximately 2 mg.
Ubiquinol-10 or CoQ10H2, the reduced form of CoQ10, plays a second role as a potent lipid-soluble antioxidant and its activity at physiological concentrations in the lipid components of cells has recently been shown.
CoQ10""s antioxidative, electron transport, and membrane-stabilizing properties have widely been investigated aiming at prevention of and/or treatment of various cardiovascular diseases, including prevention of cellular damage during reperfusion, angina pectoris, hypertension, myocardial ischemia, and congestive heart failure.
In patients with mitochondrial encephalomyopathy, CoQ10 treatment increases mitochondrial functions and exercise performance, and reduces the acidosis associated with exercise. This finding is consistent with CoQ10 participation in electron transport and mitochondrial membranes, and in the biological oxidation of cellular fuels for energy generation.
CoQ10 deficiency was also reported to be associated with viral infections, and supplementation of CoQ10 in acquired immune deficiency syndrome (AIDS) patients resulted in enhanced macrophage activity and increased serum level of IgG. CoQ10 treatment has been reported to provide some benefits in cancer patients, and enhanced hematopoietic activity in malnourished children. All the evidence suggests that CoQ10 may play essential roles in maintaining and promoting health, under normal and abnormal conditions.
It has become more and more apparent that individuals at risk and/or under treatment for mitochondriopathies are in need of increased supplementation of ubiquinones with respect to the normal intake of these substances through the diet, since particularly CoQ10 deficiency may cause the onset, precipitate or aggravate the symptoms of a serious mitochondriopathy.
Many efforts have been made over the last decade in order to find formulations that would increase the bioavailability of CoQ10 or anyhow enhance its efficacy at the cellular organelle sites of action. For instance, M. Weis et al in xe2x80x9cBioavailability of four oral Coenzyme Q10 formulations in healthy volunteers (Molec. Aspects Med. Vol. 15 [supplement] pps 273-s 280, 1994) report on a four-way randomised cross-over trial wherein the bioavailability of four different CoQ10 formulations was compared. The study results suggest that a soy bean oil suspension of CoQ10 (Bioquinon(copyright), 100 mg CoQ10 with 400 mg of soy bean oil in soft gelatine capsules) exhibits the highest bioavailability.
However, in spite of all these efforts, no satisfactory formulations able to provide a therapeutical or preventive effective concentration of ubiquinons and particularly of CoQ10 at their intracellular sites of action, have been developed to-date.
Polyunsaturated fatty acids (PUFA) are subdivided in classes based on the location of the first double bond counting from the methyl end of the fatty acid molecule: xcfx89-3 (or n-3) fatty acids have their first double bond between the third and fourth carbon atoms, and the (xcfx89-6 (or n-6) fatty acids have their first double bond between the sixth and seventh carbon atoms. Particularly importante are the xcfx89-3 fatty acids and, specifically, linolenic acid (18:3 xcfx893) (LNA), eicosapentaenoic acid (20:5 xcfx893) (EPA), and docosahexaenoic acid (22:6 xcfx893) (DHA), wherein the first number (before the colon) gives the number of carbon atoms in the molecule and the second gives the number of double bonds.
In the last two decades, epidemiologic studies, clinical investigations and animal experiments have expanded our knowledge of the properties of dietary fatty acids in health and disease, growth and development. As a recent result of these investigations, the focus is on the ratio of xcfx89-6/xcfx89-3 fatty acids in the diet; the essentiality of xcfx89-3 fatty acids and their metabolic effect in the prevention and treatment of chronic diseases. These biological and functional effects of xcfx89-3 fatty acid exert profound beneficial metabolic changes in coronary heart disease, hypertension, non-insulin-dependent diabetes mellitus, inflammatory and autoimmune disorders, and possibly cancer. For a detailed account on the sources, metabolism, biological and functional effects and dietary aspects of xcfx89-3 fatty acids see e.g. xe2x80x9cFunctional Foodxe2x80x9d edited by Israel Goldberg, Chapman and Hall (1994), Chapter 16: xe2x80x9cFatty Acidsxe2x80x9d by Artemis P. Simopoulos, pp 355-392, which is incorporated herein by reference.
We have now found that a combination composition comprising in admixture:
(a) a lipid soluble benzoquinone selected from the group consisting of Coenzyme Q10, (CoQ10), its reduced form, ubiquinol-10 (CoQ10H2) or mixtures thereof, in an amount effective for performing a therapeutical and/or preventive and/or nutritional activity in a human need thereof; and
(b) at least one omega-3 polyunsaturated fatty acid or an ester thereof, is able to enhance the pharmacological/nutritional effects of CoQ10 and/or CoQ10H2.
Although it is neither intended nor necessary to rely on any theoretical interpretation to account for the aforesaid enhanced effects, it is apparent that, most likely, they are due to the omega-3 poly-unsaturated acid acting as bioactive vehicles for CoQ10 and/or CoQ10H2 and boosters of the intramitochondrial transportation thereof to their sites of action.
The omega-3 polyunsaturated acid is selected from the group consisting of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linolenic acid (LNA) or mixtures thereof. EPA and DHA or mixtures thereof are particularly preferred. Preferred esters of LNA, EPA or DHA are the triglycerides and the ethyl ester.
The composition may also comprise saturated, monoinsaturated, omega-6 and omega-9 fatty acids or mixtures thereof. Examples of such acids are palmitic acid (16:0), oleic acid (18:1 xcfx899), linoleic acid (18:2 xcfx896), and arachidonic acid (20:4 xcfx896) or mixture thereof. If one or more of these non omega-3 fatty acids are present, the amount of the aforesaid omega-3 fatty acids, particularly EPA and/or DHA, preferably exceeds 65% and is lower than 95% by weight of the overall mixture of omega-3 fatty acids.
The weight ratio DHA:EPA in the composition ranges from 1:1 to 1:20, preferably from 1:1 to 1:5.
The weight ratio (b):(a) in the compostion ranges from 1:20 to 1:50.
The composition of the present invention may further comprise xcex1-tocopherol (vitamin E) as component (c). Preferably, the weight ratio (b):(c) in the composition ranges from 1:20 to 1:50. We have found that the aforesaid omega-3 fatty acids act as bioactive vehicles towards Vitamin E as well, i.e. they enhance the parmacological effects of Vitamin E.
The efficacy of the compositions according to the present invention towards many forms of mitochondriopathies and the ability of the same compositions to enhance the intramitochondrial transportation of CoQ10 was shown in clinical trials. As an istance of the successful treatment of a mitochondriopathy, a study on patients affected by photophobia and ARMD is reported hereinbelow.
The following retinal model for assessing mitochondriopathy was used.
As known, reactive oxigen species (ROS) may be generated at least at three sites in the retina:
in the photoreceptor cell during light stimulation.
in the retinal pigmented epithelium (RPE), which phagocitize photoreceptor discs during normal turnover and light stimulation.
in the neuroretina at the synaptosomes.
In each of these three sites, mitochondria are the common source and target of ROS.
We found that in the normal retina, mitochondrial membranes of the photoreceptor cells have significantly different molecular structure than those of the outer segment discs. The mitochondrial membranes are more basophilic, and they contain more unsaturated lipids than the disc membranes of the outer segments. Further, in vitro studies of normal human photoreceptors cells showed, that the behaviour of mitochondrial and disc membranes is different when they are exposed to oxido-reductive stress. The same oxidative stress which resulted in reversible alteration of the disc membranes, caused irreversible damage of the mitochondrial membranes. However, the exposure to strong electron donor substances (chlorpromazines) slighly altered the structure of mitochondrial membranes, but it disrupted the disc membranes in dose dependent manner. These findings suggested that mitochondrial membranes are more sensible to oxidative, while disc membranes are more sensible to reductive influences.
Via electron microscopic studied on diseased human retinas, we showed that mitochondrial damage is a typical alteration in age-related macular degeneration (ARMD), myopic retinal dystrophies (NRD) and in retinitis pigmentosa (RP). Mitochondrial alterations included loss of the cristae, accumulation of intramitochondrial lipid droplets, swollen of the mitochondria, and decrease in number of them were observed in diseased RPE and photoreceptors cells. Pigment epithelial cells were predominantly affected in ARMD and MRD, while in RP both photoreceptor and pigmented epithelial cells were seriously altered.
These findings suggested that the retina is a suitable model for assessing mitochondriopathy.
We performed open, controlled studies of the various compositions of CoQ10 and alpha tocopherol with or without the addiction of omega-3 fatty acids. In each series of healthy volunteers and photophobia patients the treatment was applied for one month, while in the series of ARMD patients it was for three months. To evaluate visual function before and after treatment, as well as after one month of xe2x80x9cwash-outxe2x80x9d macular photostress test was applied.
Macular Photostress Test: 60 seconds bright light illumination to one eye (the follow eye was covered) by standardized slit lamp (full aperture and maximum intensity of a Haag-Streit slit lamp). Contrast sensitivity was tested by Maffei decimal chart before and after the illumination and the recovery time was measured (i.e. measured the time when the eye was able to read the same figure, as before the photostress). This function of the retina depends on the metabolic support to light stimulation-regeneration, thus a very suitable method for evaluate mitochondrial functions (Wu, G., Weiter, J. J., Santos, S., Ginsburg, L., Villalobos, R.: The macular photostress test in diabetic retinopathy and age-related macular degeneration. Arch. Ophthalmol., 108, 1556-58 (1990).
Blood levels of total, HDL, and LDL cholesterol and triglicerid levels were evalutated before, after three months of treatment, and after one month xe2x80x9cwash-outxe2x80x9d in the ARMD group.
12 healthy volunteers were enrolled in this clinical trial (6 male, 6 female, aged 24-37 years, mean body weight 66,5 kg).
1st group: treated with 50 mg CoQ10 granulated+70 mg vitamin E/day
2nd group: treated with 100 mg CoQ10 granulated+70 mg vitamin E/day
3rd group: treated with 30 mg CoQ10 in soy bean oil+30 mg vitamin E/day
4th group: treated with 30 mg CoQ10 in omega-3 ( greater than 65% conc.)+30 mg Vitamin E/day
Results
healthy volunteers react very poorly to these treatments;
pharmacological effect of 50 mg CoQ10 granulated+vitamin E was insignificant;
lipid addition improved dose-efficacy relation of CoQ10+vitamin E (100 mg. CoQ10 granulated were equivalent 30 mg of CoQ10 dissolved in soy bean oil);
highly concentraded PUFA was the most effective treatment.
16 patients suffered from photophobia were entrolled in this trial (11 female, 5 male, aged 23-44 years, mean body weight 63,4 kg).
1st group: treated with 100 mg CoQ10 granulated+70 mg vitamin E/day
2nd group: treated with 30 mg CoQ10 in soy bean oil+30 mg vitamin E/day
3rd group: treated with 30 mg CoQ10 in fish oil ( greater than 30% conc.)+30 mg vitamin E/day
4th group: treated with 30 mg CoQ10 in omega-3 ( greater than 65% conc.)+30 mg Vitamin E/day
Results
The pharmacological effect of CoQ10+vitamin E was approximately double in cases of photophobia than in healthy volunteers.
omega-3 enhances intensity and duration of the parmacological effects of CoQ10+vitamin E;
higher concentration of omega-3 was showed better effects than lower concentration: the differences were 50% after one month of treatment, and approximately 30% after one month of xe2x80x9cwash-outxe2x80x9d.
43 patients affected by early age-related macular degeneration (visual acuity better than 20/40) were involved in these studies (23 female, 20 male, aged between 55-66 years, mean body weight 66,8 kg).
1st group: treated with lutein+zeaxantin+vitamin E (a commercially available product)
2nd group: treated with 1.000 mg omega-3 ( greater than 65%) only
3rd group: treated with fish oil+30 CoQ10+30 mg vitamin E/day
4th group: treated with omega-3 ( greater than 65%)+30 mg CoQ10+30 mg Vitamin E/day
Results
There were no significant differences between the groups treated with a commercially available dietary supplement (containing lutein, zeaxantin and vitamin E) and omega-3 ( greater than 65%) alone.
CoQ10+vitamin E in highly concentrated omega-3 was more effective than fish oil+CoQ10+vitamin E, after 3 months (50%) and after one month of wash-out (30%);
highly concentrated ( greater than 65%) PUFA showed synergistics pharmacological effects with CoQ10 and vitamin E, superior than those of low concentration PUFA or saturated lipids;
highly concentrated ( greater than 65%) PUFA administration showed lowering of the plasma triglyceride levels and improved the ratio of total/HDL cholesterol, which was not observed in fish oil (30% omega-3) treated cases. In contrary, in 3 of the 12 cases, increase of total cholesterol and/or triglicerid levels were observed.
Conclusions
These pharmacological studies showed that CoQ10+vitamin E in a vehicle of highly concentrated polyunsaturated fatty acids improved retinal function, primarily the regeneration of photoreceptor cells in normal conditions and in diseases states.
The most likely cellular target of these substances is the mitochondria of photoreceptor cells. The longer duration of visual improvement, a particularly important pharmacological effect, indicates that the composition of the present invention achieves a higher intracellular concentration of CoQ10 and/or higher affinity of this substance to the target organelles than those accomplished via the usual enterally administrable CoQ10-containing formulations at present commercially available.

Ubiguinone-containing composition suitable for promoting enhanced intramitochondrial transportation of ubiguinones and methods of using same


A tissue gripping apparatus including a cylindrical member positioned about a tubular body portion or cannula. The cylindrical member includes a plurality of articulated arms that are movable between engageable and non-engageable positions. A hinge in the articulated arm enhances the tissue gripping abilities of the apparatus.

1. Field of the Invention
The present invention relates to surgical instruments for performing laparoscopic and endoscopic surgical procedures, and more particularly to a device for securing instruments such as cannulas in an incision in a patient's body during the surgical procedure.
2. Discussion of the Prior Art
In recent years, laparoscopic and endoscopic surgical procedures have become increasingly popular for performing major surgical operations. In such a procedure, a small incision or puncture is made in the patient's body to provide access for a tube or a cannula device. The tube or cannula device is inserted into the patient's body to allow for the insertion of instruments used in performing the surgical procedure, as well as for the insertion of a camera or endoscope to view the surgical objective.
Typically, a trocar device including, for example, an obturator and a cannula is employed to puncture the skin and provide access to the surgical area. A pointed obturator may be used for penetrating the skin to extend the trocar beyond the body wall to the surgical site. Alternatively, an incision may be made using a scalpel or similar device before inserting a blunt obturator through the incision. When either obturator is removed, the cannula remains in place to maintain access to the surgical site, and several incisions may be made to provide numerous access ports to the surgical objective. Once the cannulas are in place, various surgical instruments such as scissors, dissectors, retractors or the like, may be inserted by a surgeon to perform the surgery. Typically, a scope device is used to view the area directly, or a miniature camera is used to display the surgical site on a video monitor in the operating room.
The primary benefit of such minimally invasive surgical techniques is the reduction of scarring, and consequently, minimizing damage to surrounding tissue and organs. As a result, recovery time is greatly reduced for the patient.
During a laparoscopic surgical procedure, gas is introduced into the body cavity, usually the abdomen, by means of a pneumoperitoneum needle. The gas inflates the abdominal cavity to provide greater access to the surgical area and minimize obstruction during surgery. The trocar assembly is then inserted into the body cavity to a point adjacent the tissue or organ which is the surgical objective. Due to the gas insufflation, it is necessary to maintain a desired gas seal at each of the cannulas in position in the body. After the obturator is removed from the trocar assembly, the cannula remains in place in the patient's body. Ordinarily, a flapper valve in a housing at the proximal end of the cannula prevents the insufflation gas from escaping through the cannula after the obturator is removed. It is also preferred to maintain the cannulas in a relatively stable state, primarily to free the surgeon and the surgical assistants from having to hold the cannulas to prevent these instruments from backing off and consequently being displaced from the incision. Furthermore, the routine movement of the cannulas during the surgical procedure may result in a loss of gas tightness about the cannula, thereby negatively effecting the surgical procedure.
In order to support the cannula in a hands-off manner, and maintain the integrity of the gas seal at the incision, it has been known to provide various mechanisms and devices which attempt to maintain and secure the cannula in the incision.
Typical devices include penetration limiting devices such as the sleeve or collar disclosed in U.S. Pat. No. 3,817,251 to Hasson, which provides a conical sleeve which may be adjusted to various positions on the cannula to limit insertion of the cannula to specific depths. U.S. Pat. No. 4,077,412 to Moossun, U.S. Pat. No. 4,637,814 to Leiboff, as well as U.S. Pat. No. 4,627,838 to Cross et al., disclose devices to prevent the inadvertent removal or backing off of the cannula during the surgical procedure. Moossun provides an inflatable diaphragm member which is inflated once the cannula is positioned in the body cavity to prevent inadvertent removal of the cannula from the incision until the diaphragm is deflated. Leiboff also discloses an inflatable cuff member which is inflated in a body cavity to secure the device and seal the cavity at the opening to prevent leakage of irrigating fluid during an irrigation procedure. Cross et al. provide a complex wing-type mechanism which is extended once the catheter is positioned within the body cavity so that the wing members engage the body wall to prevent removal of the catheter until the wing mechanism is collapsed. These devices often require additional equipment to be present in the operating room, such as a gas or compressed air source to inflate the device.
Also known are sleeve members having external ribs which fit over a cannula. The sleeve is forced into the incision either by twisting or simply by forcing the sleeve into the incision along with the catheter. Further, devices are known that include a "Malecott" type wing arrangement such as U.S. Pat. 4,608,965 to Anspach, Jr. et al. Anspach discloses an endoscopic retainer and tissue retracting device including a cylindrical tube having flexible strips at a distal end. The device is placed over an endoscope and the retracting device's flexible strips are expanded by a surgeon to retract tissue and retain the endoscope in position.
The novel tissue gripping device of the present invention obviates the disadvantages encountered in the prior art and provides improvements which are desirable for enhancing the retention properties of the cannula in the body wall. The device of the present invention provides a tissue gripping device which may work in concert with a cannula to retain the cannula in the body wall through the provision of articulated flexible members which extend outwardly to engage the body wall when in their extended position. The device includes means to positively retain the flexible members in an extended position so that the cannula is maintained in the body wall without the requirement of having surgical personnel hold the cannula in place.

Tissue gripping apparatus for use with a cannula or trocar assembly


A switching arrangement for the control of an adjustable member such as a valve includes a light sensitive switch. Detection of a particular light value enables a frequency divider to transmit an opening pulse to a valve control circuit a predetermined delay period after the detection of such light value. The frequency of an output signal of a pulse generator is varied in response to the opening pulse and the frequency divider transmits a closing pulse to the control circuit after a second predetermined time period of different duration from the delay period. In one disclosed embodiment, control of the frequency divider is responsive to moisture content of soil as well as ambient light level for application in automatic sprinkler systems.

The invention relates to a switching arrangement for the control of an adjustable member, such as a valve, whereby the adjustable member is turned off or closed automatically after an adjustable time period during which the adjustable member was on or opened. The invention particularly relates to the control of a valve which forms part of an automatic sprinkling system.
Experience has shown that watering of a garden or lawn is most successful whenever the sprinkling is carried out at the onset of twilight. Consequently very many gardens are sprinkled at this time, so that the pressure in the water mains fluctuates with a relatively high degree of variation from the normally encountered pressure. If automatic sprinkling is carried out at this time, the success of watering, which is difficult to estimate in advance, would tend to be irregular.
In prior art automatic sprinkling systems a water control clock mechanism is used to control the sprinklers. The clock mechanism closes an adjustable valve in series connection with a water sprinkler after the course of a manually initiated valve open period set on the clock mechanism. Automatic opening of the valve is not possible with this arrangement, so that it cannot be used whenever a water sprinkler is to be turned on and off daily, for several days.
Furthermore, this type of prior art control for water sprinkling systems operates with a precision clock mechanism, which is sealed against the water carrying parts of the arrangement. This sealing requires a considerable construction expenditure.
An electric time switching clock is available on the market by means of which an electric circuit may be turned on and off daily at certain times during a 24 hour period. The times of turning on and off may be adjusted successively. However, the use of such an electric switching clock to overcome the difficulties mentioned above with respect to twilight watering is prohibitive, as it would represent an unnecessary expense due to the cost of the clock mechanism and moreover may be adjusted for a time dependent upon twilight only after special considerations, calculations, and adjusting efforts.

Automatic control for an adjustable member


Methods described include placing a sensor system over a substrate positioned on a chuck. The sensor system generates a beam of optical energy towards the substrate and is configured to receive optical energy deflected from the substrate. The sensor system generates sensor signals in response to variations in received optical energy from the substrate and the chuck.

Nano-fabrication involves the fabrication of very small structures, e.g., having features on the order of nanometers or smaller. One area in which nano-fabrication has had a sizeable impact is in the processing of integrated circuits. As the semiconductor processing industry continues to strive for larger production yields while increasing the circuits per unit area formed on a substrate, nano-fabrication becomes increasingly important. Nano-fabrication provides greater process control while allowing increased reduction of the minimum feature dimension of the structures formed. Other areas of development in which nano-fabrication has been employed include biotechnology, optical technology, mechanical systems and the like.
An exemplary nano-fabrication technique is commonly referred to as imprint lithography. Exemplary imprint lithography processes are described in detail in numerous publications, such as U.S. patent application publication 2004/0065976, U.S. patent application publication 2004/0065252, and U.S. Pat. No. 6,936,194, all of which are assigned to the assignee of the present invention, and incorporated by reference herein.
The imprint lithography technique disclosed in each of the aforementioned U.S. patent application publications and U.S. patent includes formation of a relief pattern in a polymerizable layer and transferring a pattern corresponding to the relief pattern into an underlying substrate. The substrate may be positioned upon a motion stage to obtain a desired position to facilitate patterning thereof. To that end, a template is employed spaced-apart from the substrate with a formable liquid present between the template and the substrate. The liquid is solidified to form a solidified layer that has a pattern recorded therein that is conforming to a shape of the surface of the template in contact with the liquid. The template is then separated from the solidified layer such that the template and the substrate are spaced-apart. The substrate and the solidified layer are then subjected to processes to transfer, into the substrate, a relief image that corresponds to the pattern in the solidified layer.

This patent is subject to a terminal disclaimer.

Alignment system and method for a substrate in a nano-imprint process


Devices and methods for positioning a portion of a sensor at a first predetermined location, displacing the portion of the sensor from the first predetermined location to a second predetermined location, and detecting one or signals associated with an analyte level of a patient at the second predetermined location are disclosed. Also provided are systems and kits for use in analyte monitoring.

There are many instances in which it is necessary to position at least a portion of a medical device beneath the epidermis of a patient, e.g., in the subcutaneous layer or elsewhere.
For example, the monitoring of the level of glucose or other analytes, such as lactate or oxygen or the like, in certain individuals is vitally important to their health. The monitoring of glucose is particularly important to individuals with diabetes, as they must determine when insulin is needed to reduce glucose levels in their bodies or when additional glucose is needed to raise the level of glucose in their bodies.
In this regard, devices have been developed for continuous or automatic monitoring of analytes, such as glucose, in the blood stream or interstitial fluid. Many of these analyte measuring devices are configured so that at least a portion of the devices is positioned below the epidermis, e.g., in a blood vessel or in the subcutaneous tissue of a patient.
These devices, as well as other medical devices, may be positioned manually, e.g., by a user or a healthcare worker, or automatically or semi-automatically with the aid of a sensor positioning device. Regardless of the manner in which the device is inserted beneath the skin, it is important that the device positioning process does not adversely affect the operation of the device. Furthermore, it is important that pain is minimal.
As interest in inserting medical devices, e.g., continuous analyte monitoring devices, beneath the epidermis of a patient continues, there is interest in devices and methods for operably inserting such devices. Of interest are such devices and methods that have minimal impact on device function and which produce minimal pain. Of particular interest are continuous analyte monitoring positioning devices that enable clinically accurate analyte information to be obtained substantially immediately following device positioning in a patient.

Method and apparatus for providing analyte sensor insertion


A communication device and method in which actuation of a function key, corresponding to at least one function associated with a remotely located voice messaging system, causes a command related to the actuated function key to be generated and sent to the voice messaging system. The predetermined function keys correspond to voice messaging system functions, such as listen to a message, skip a message, replay a message, delete a message, play a previous message, and fast forward through a message.

1. Field of the Invention
The present invention relates to the field of tele-communications. More particularly, the present invention relates to a system and a method for retrieving voice messages from a network voice message system.
2. Description of the Related Art
A conventional network voice mail system, or network voice messaging system, records messages at a facility connected to a telecommunications network for subscribers who are unavailable for answering a telephone call. A subscriber retrieves messages by calling a telephone number associated with the network voice message system to access the messaging system. The subscriber then enters identification information, and sends control commands into the system using the keys of a standard telephone keypad.
As another approach for retrieving messages and controlling a voice messaging service, U.S. Pat. No. 4,964,156 to Blair discloses a cellular telephone that automatically initiates a connection to a network voice mail system when the telephone is powered on. The cellular telephone automatically dials the telephone number of the voice mail system and sends user identifying information upon connection with the messaging system. Upon verification of the identifying information, the user conducts a conventional voice mail session for retrieving messages using the keys of a standard telephone keypad.
Other techniques for providing voice messaging-type services also exist. For example, U.S. Pat. No. Re. 34,976 to Helferich et al. discloses a cellular telephone that records voice messages in a memory in the cellular telephone when the telephone user is unavailable for answering a call. After a predetermined number of rings, the voice messaging circuitry within the telephone is activated for digitally recording a message in the memory of the cellular telephone so that the user can retrieve the message at a later time. According to Helferich et al., a voice mail message can be stored initially at a network voice mail system when the telephone user is unavailable for answering a call. The voice mail message is then transmitted to the memory of the cellular telephone at a later time using a high transmission rate, thereby reducing the air transmission time. This approach requires that the cellular telephone have sufficient memory for recording a useful amount of messages, thus making the cellular telephone more expensive for a user. Additionally, a user keys in an identification number using a standard telephone keypad to listen to a message recorded in he memory.
The conventional approach of retrieving messages and controlling remotely located voice messaging systems by using a standard telephone keypad is inconvenient because a user must interface with a network voice messaging system using a standard telephone keypad, while listening to an audible message providing a list of commands and/or system functions in a menu-type format.
The present invention provides a communication device having a convenient interface for controlling a remotely located voice messaging system. According to the invention, the communication device includes a keypad having function keys for controlling the network voice messaging system. The function keys include keys for listening to a message, fast forwarding through a message, rewinding a message, skipping a message, playing a previous message, and deleting a message, for example. A speed dial key can be included with the present invention for conveniently initiating access to the remote voice messaging system. In addition to providing a convenient interface to a network voice messaging system, the device of the present invention may also function as a conventional wireless telephone and/or voice paging device.

System and method for retrieving messages from a voice message system


A tent with an exterior screen structure (200) having an inner tent structure (310), including an inner fabric enclosure (311) which serve as walls (328, 330, 332), roof (334) and floor (336) of the inner tent structure (310) and an outer tent structure (210) including an outer fabric enclosure (211). A single frame (212) supports both inner (311) and outer fabric enclosures (211).

The present invention relates generally to cabin tent structures, and more particularly to tent pole and hub systems as well as fabric-covered structures
One of the earliest forms of shelter known to humankind is the tent. Huge variety in tent design exists, but common elements include tent fabric and tent poles which shape and support the fabric. Most tents use multiple tent poles, often with hubs connecting the tent poles together. It therefore becomes the combination of poles and hubs which define many characteristics of such tents. Examples of important characteristics include structural shape, rigidity, ability to support the tent fabric, and reaction to externally applied stresses such as those caused by bumping into the tent or from wind buffeting the tent and causing the walls to vibrate.
For purposes of the following discussion, tent poles will be classed as side poles, gable poles, ridge poles, and horizontal poles. In assembled tents, side poles extend in a generally vertical orientation from the ground surface up to the beginning of the roof region of a tent. Gable poles extend from the edge of a tent roof upward to the peak of the tent roof, and have a sloping orientation (i.e., generally in the range of 30 to 60 degrees relative to horizontal). Ridge poles are generally horizontal, but for discussion here are strictly defined as being at the peak of the tent roof (the term tie pole is sometimes used for this). Finally, horizontal poles are herein strictly defined as including all generally horizontally oriented poles except ridge poles (e.g., they include poles typically used at the eaves or lower roof edges of some tent designs).
Balancing tent pole system characteristics is not an easy engineering task. Some of the already mentioned characteristics urge contradictory engineering solutions. For example, strong rigid shapes generally are best accomplished by framing the shape in closed geometric shapes, such as the triangular and rectangular members used in engineering wire-frame drawings. Unfortunately, while framed sections are strong and rigid, they also transmit force and vibration very well, often with undesirable results. Further, framed sections may require more parts than other designs, and therefore may result in increased overall tent weight and cost. Thus, optimizing only some characteristics may conflict with general goals for an entire tent system.
For discussion here, tent pole systems can be defined as free standing, pre-stressed, and gravity assisted systems. In the market today, the free standing system is used primarily for larger tents (including yurts, and show tents); the pre-stressed construction is used primarily in smaller, shorter type (one and two person) portable tents; and gravity assisted systems are primarily used for cabin tents (i.e., tents large enough to accommodate at least a small family, and usually tall enough that an average adult can stand fully upright in the tent center). A good example of a free standing tent system is the teepee. It has a very strong and rigid frame over which fabric is draped. However, the fabric adds nothing to the strength or shape of the finished tepee. When designing tepees the tent fabric and the tent pole system are effectively two unrelated problems. At an opposite extreme are pre-stressed pole systems, good examples of these can be found today in tents using fiberglass poles which are bent into place during assembly and held together by the tent fabric in a spring-like manner to define the tent structure. Attempting to assemble such a tent with only the poles and hubs (if any) would be impossible, or at best produce a very flimsy structure. Finally, in a category falling between the free standing and pre-stressed systems are gravity-assisted systems. Many cabin tents in the market today belong in this classification. In such tents the poles do not form as strong a system as when no tent fabric is assembled onto them, nor are the tent poles intentionally bent in the manner of springs to assemble and tension the tent. Rather, once assembled onto a finished tent, the fabric under the weight of gravity helps to define and stabilize the final tent structure. In such tents the critical components become the hubs used to connect the tent poles, since it is in these that forces concentrate and must be accommodated.
Various forces are applied to tent hubs, either directly, or more commonly indirectly, through the tent poles inserted into the hubs. One such force is fabric weight, which actually may be variable, since rain, snow, and other substances can xe2x80x9cweigh downxe2x80x9d tent fabric. External stresses form another group of forces which also ultimately reach the hubs. Assembled tents may be bumped by users who are either inside or outside of the tent. And when present, wind may range from constantly pressing against the tent from one direction to buffeting it from rapidly changing directions at different speeds, thereby causing vibration in the tent structure. It therefore follows that for a cabin tent design to be acceptable the hubs which are used must successfully deal with all of these forces.
Additional concerns for many tent designs are parts count and overall tent weight. Reducing parts count has the obvious advantage that fewer parts mean less loss or misplacement and almost always reduces cost also, particularly if the eliminated parts are tent poles made of aluminum. And, usually, reducing parts count leads to a more intuitive assembly process, and sometimes a simpler one as well. Further, it may strongly affect tent weight. Generally, of the three major components used in cabin tents the fabric is least dense, the hub has intermediate density (at least in plastic hubs, as are preferred today), and the poles are most dense, since they are metal or high density plastic like fiberglass. There are, of course, also notable size differences in these components. For example, hubs and poles are markedly different in size. Thus, by accepting some size increase in smaller less dense parts, to eliminate some high density large parts entirely, an overall weight savings may be accomplished by selective parts count reduction.
From the above discussion it should be clear that good tent design must balance many factors.
Accordingly, it is an object of the present invention to provide a tent which can be assembled in very little time, and with a minimum of separate pieces.
Another object of the invention is to provide a tent which has a convertible roof.
And, another object of the invention is to provide a tent which has an exterior screen structure.
Briefly, one preferred embodiment of the present invention is an improved tent for quick construction, including a fabric enclosure which serves as walls, roof and floor of the tent. The tent also includes a frame which attaches to and supports the fabric enclosure. The frame includes at least two frame poles having upper and lower ends. The frame poles form at least one V-shape, the lower ends being positioned in close proximity to form the tip of the V-shape, and the upper ends spread apart forming the legs of the V shape. The upper ends tend to fall away from each other on either side of a bisecting vertical line to the extent allowed by their attachment to the fabric enclosure, thereby spreading the fabric enclosure and aiding in the quick construction of the tent.
A second preferred embodiment of the present invention is a convertible tent which includes a fabric enclosure which serves as walls, roof and floor of the tent. A frame supports the fabric enclosure and configures the fabric enclosure into a tent. The tent roof includes a top portion and a screen portion, the top portion being convertible so that the screen portion is exposed.
A third preferred embodiment of the present invention is a tent with an exterior screen structure having an inner tent structure, including an inner fabric enclosure which serve as walls, roof and floor of the inner tent structure and an outer tent structure including an outer fabric enclosure. A single frame supports both inner and outer fabric enclosures.
An advantage of the present invention is that the first preferred embodiment contains a V-shaped side support structure which minimizes the number of pieces required for assembly of the tent.
Another advantage of the invention is that a second preferred embodiment contains a screened roof portion which can be exposed to present a convertible roof.
And, another advantage of the invention is that a third preferred embodiment includes a inner structure which is enclosed by an outer screen structure. The space between the inner and outer structures provides a protected living area for users.
These and other objects and advantages of the present invention will become clear to those skilled in the art in view of the description of the best presently known mode of carrying out the invention and the industrial applicability of the preferred embodiment as described herein and as illustrated in the several figures of the drawings.


A process for producing aluminum metal by carbothermic reduction of alumina ore. Alumina ore is heated in the presence of carbon at an elevated temperature to produce an aluminum metal body contaminated with about 10-30% by wt. aluminum carbide. Aluminum metal or aluminum alloy scrap then is added to bring the temperature to about 900-1000xc2x0 C. and precipitate out aluminum carbide. The precipitated aluminum carbide is filtered, decanted, or fluxed with salt to form a molten body having reduced aluminum carbide content.

1. Technical Field
This invention relates to a carbothermic process for the direct thermal reduction of aluminum oxide to form aluminum metal.
2. Background
The predominant commercial process today for producing aluminum metal is the Hall-Heroult process of electrolytically dissociating alumina dissolved in a fused cryolitic bath at a temperature less than about 1000xc2x0 C. Many attempts have been made to replace this process and produce aluminum commercially by a direct thermal reduction process of aluminum oxide with carbon at sufficiently high temperatures according to a reaction written as equation (1).
Al2O3+3Cxe2x86x922Al+3COxe2x80x83xe2x80x83Eq. (1)
Aluminum may be produced by the carbothermic direct thermal reduction of alumina, e.g., in an open or submerged-arc electric or slag resistance heating furnace. The scientific principles involved in the chemistry and thermodynamics of the reactions are now fairly well understood (C. N. Cochran, Metal-Slag-Gas Reactions and Processes, Electrochem. Soc., Princeton, N.J. 1975, pp. 299-316; K. motzfeldt and B. Sandberg, Light Metals 1979, A I M E, New York, N.Y. 1979, Vol. 1 pp. 411-428, and references cited therein). Nonetheless, no commercial process based on these principles has been established.
The carbothermic direct thermal reduction process involves reacting an aluminum oxide containing compound with a reductant which is usually carbon, aluminum carbide, or a mixture thereof in an electric furnace to reduce the aluminum oxide to metallic aluminum. Although the reaction on first impression would appear to be a simple one, i.e., the reduction of aluminum oxide to aluminum, substantially pure aluminum is not obtained via conventional carbothermic processes and, in fact, the product tapped from the furnace is aluminum contaminated with aluminum carbide. The amount of contamination with aluminum carbide varies depending on the particular carbothermic process which is carried out, but, in general, conventional carbothermic processes result in the production of aluminum contaminated by 10-30% by weight of aluminum carbide.
The carbothermic direct thermal reduction process has presented a substantial technical challenge in that certain difficult processing obstacles must be overcome. For example, at the temperatures necessary for the direct thermal reduction of alumina to form aluminum, e.g., such as about 2050xc2x0 C., the aluminum volatilizes to a gas of aluminum metal or aluminum suboxide rather than forming as aluminum metal liquid which may be tapped from the process. For this reason, most attempts have incorporated an electrical furnace for the purpose of reducing the amount of volatile gaseous constituents in the system.
In attempts to reduce alumina thermally with carbon in the absence of other metals or their oxides, substantial amounts of aluminum carbide are produced according to the reaction written as equation (2).
2Al2O3+9Cxe2x86x92Al4C3+6COxe2x80x83xe2x80x83Eq. (2)
Equation (2) proceeds favorably at or above 1800xc2x0 C. Other intermediate compounds also are formed such as oxycarbides by the reactions written as equation (3) and equation (4).
4Al2O3+Al4C3xe2x86x923Al4O4Cxe2x80x83xe2x80x83Eq. (3)
Al4O4C+Al4C3xe2x86x924Al2OCxe2x80x83xe2x80x83Eq. (4)
The reduction of alumina by carbon, when carried out under reduced pressure, proceeds with aluminum oxycarbide and aluminum carbide as intermediate products written as equation (5) and equation (6).
xe2x80x832Al2O3+3Cxe2x86x92Al4O4C+2COxe2x80x83xe2x80x83Eq. (5)
Al4O4C+6Cxe2x86x92Al4C3+4COxe2x80x83xe2x80x83Eq. (6)
Below 1900xc2x0 C., all reactants and products except CO are solids. To attain an equilibrium gas pressure of 1 atm, however, temperatures of around 2000xc2x0 C. are required, the reaction mixture is partially molten, and the simple equations (5) and (6) are no longer directly applicable. Likewise, the final, metal-producing step might be written as equation (7).
Al4O4C+Al4C3xe2x86x928Al(l)+4COxe2x80x83xe2x80x83Eq. (7)
The equilibrium gas pressure for this reaction reaches 1 atm at about 2100xc2x0 C. In a reduction furnace operated under atmospheric pressure, the reaction zone must be maintained at a temperature at least sufficient to give the equilibrium pressure of CO equal to 1 atm. Allowing for some over-pressure to drive the reaction means a temperature of about 2150xc2x0 C. At this temperature, the system includes solid carbon plus two liquids, an oxide-carbide melt and a metallic melt or metal melt. Equation (7) is not applicable, and the metal-producing reaction may be written schematically as equation (8).
xe2x80x83(oxidexe2x88x92carbide melt)+C(s)xe2x86x92(metal melt)+COxe2x80x83xe2x80x83Eq. (8)
Concurrent with the production of carbon monoxide and condensed products, volatile aluminum-bearing species Al2O(g) and Al(g) also will be formed. In the first steps of the reaction, formally described by equation (5) and equation (6), the equilibrium pressures of Al2O and Al amount to only a few percent of the equilibrium pressure of CO. In the final step, represented by equation (7) or equation (8), the proportions of Al2O and Al in the equilibrium gas are higher, but not excessive. It has been shown, however, that the reaction between alumina and carbon proceeds via a mechanism involving a gas phase with a high proportion of Al2O and Al, and, as a consequence, the losses by volatilization will be higher than those expected from the equilibria. Further, the metallic melt has a lower density than that of the oxide-carbide melt and thus the metallic melt floats on top of the oxide-carbide melt. The CO gas evolved by reaction (8) must pass through the metal melt, which further increases losses by volatilization.
Volatilization of Al and Al2O from the hot zone does not necessarily lead to metal loss. In a submerged-arc furnace, the reaction gas passes upwards through layers of colder charge, where the metal-bearing vapors may condense, at the same time preheating the charge. With a high fraction of metal vapors in the gas, however, the charge runs too hot, and losses by volatilization occur.
A primary difficulty in the carbothermic production of aluminum is caused by the substantial solubility of carbon in the metal at reaction temperature, about 20 atom % C. when the metallic melt is in equilibrium with solid carbon. When the melt is cooled, the carbon precipitates as aluminum carbide as written in equation (9).
(12Al+3C, molten mixture)xe2x86x92Al4C3(s)+8Al(l)xe2x80x83xe2x80x83Eq. (9)
About one-third of the metal value is precipitated as carbide. This necessitates a subsequent separation step, and recycling of the aluminum carbide, which is a disadvantage to the economy of the process.
Another difficulty in the carbothermic reduction of alumina in a submerged-arc furnace relates to the energy input and heat transfer. The metallic melt floats on top and will be directly underneath the electrodes. Because of the high electrical conductivity of the metal, the resistance in the furnace circuit will be low, and difficulties are experienced in maintaining an adequate energy input to the furnace. Further, the heat generation will take place predominantly on the surface of the metal, leading to very high metal temperature and substantial evaporation. To the extent this metal is condensed in the charge above the melt, it runs right back into the hot zone and is re-evaporated. The net result of this cyclic process of vaporization and condensation is that a large fraction of the generated heat is transferred upwards in the furnace, instead of being conducted downwards to the oxide-carbide melt where the heat is needed for the endothermic reaction (8).
The carbides and oxycarbides of aluminum readily form at temperatures lower than the temperatures required for significant thermal reduction to aluminum metal and represent a substantial slag-forming problem in any process intended to produce aluminum metal.
All the major oxides in bauxite except zirconia are reduced by carbothermic smelting before alumina is reduced. In practice, the oxides do not behave as simply as predicted. Instead, intermediate compounds are formed such as carbides, oxycarbides, and volatile subcompounds.
Most processes for the carbothermic production of aluminum always result in the production of aluminum contaminated with aluminum carbide, and the aluminum carbide contamination can be in the range of 20 weight percent or higher. A severe practical difficulty arises in attempting to purify aluminum contaminated with aluminum carbide in significant amounts because the mixture becomes non-pourable unless extremely high temperatures are maintained, such that the problem of purifying the mass becomes complex.
The amount of aluminum carbide contamination bears a direct relationship to the temperature employed, i.e., at the normal reduction temperatures employed in a furnace, the amount of aluminum carbide which can dissolve in the formed aluminum is about 20 weight percent or higher. Most processes result in the production of high aluminum carbide-containing products for the simple reason that they utilize uniform heating such that the majority of the charge was at a uniformly high temperature and, therefore, it was possible to dissolve aluminum carbide in appreciable amounts.
In one process, the furnace operation is carried out such that an intermittent type of heating is applied to the charge to be reduced so that a portion of the charge is at reaction temperature (about 2100xc2x0 C.) but a majority of the charge is not at reaction temperature at any given time. Accordingly, when the formed aluminum flows over the charge, the charge is never at a temperature where more than about 10 weight percent aluminum carbide dissolves in the molten aluminum.
The present standards for commercially pure aluminum do not allow a significant quantity of aluminum carbide to be present, so that the furnace product from most carbothermic reduction processes must be subjected to further processing steps to reduce the aluminum carbide content to an acceptable level. The processes for reducing the aluminum carbide content from the product of a carbothermic reduction furnace have been found to be time consuming, expensive, and not economically feasible.
The aluminum carbide content of at least a portion of the aluminum produced by a carbothermic direct thermal reduction process can be decreased by cooling the furnace melt so that an aluminum carbide matrix is formed whereby the aluminum carbide matrix squeezes out aluminum to the surface of the melt and this aluminum can be removed by any suitable technique, including decanting. The aluminum removed in this manner is diminished in aluminum carbide content, but only a small portion of the available aluminum is recovered.
The yield of aluminum from a carbothermic reduction process can be enhanced by utilizing a mechanical working. A technique of this type subjects moving equipment under severe stress to very hot and corrosive conditions.
In one process, a mixture of aluminum contaminated with aluminum carbide in the molten state contacts certain gases which interact with or operate upon aluminum carbide to prevent the formation of an aluminum carbide matrix which would entrap the aluminum. Treatment involves blowing the gas through the body of the melt of aluminum and aluminum carbide.
Fluxing with metallic salts can diminish the amount of aluminum carbide contamination, but the molten salts mix with the carbide so removed, and it is costly to remove the carbide from the salt so that the carbide can be recycled to the furnace. Without such recycle, the power consumption and furnace size become uneconomical in comparison with methods practiced commercially today for making aluminum.
For over 100 years, aluminum has been produced by the two part Bayer-Hall process, wherein alumina (Al2O3) first is extracted from bauxite ore, and the alumina then is reduced electrolytically in molten cryolite (sodium aluminum fluoride) to free aluminum metal. Although the process has been highly successful commercially, it consumes large quantities of electricity and takes about four pounds of bauxite to produce one pound of aluminum. Bauxite typically comprises 45 to 60 percent aluminum oxide, 3 to 25 percent iron oxide, 2.5 to 18 percent silicon oxide, 2 to 5 percent titanium oxide, up to one percent other impurities, combined with 12 to 30 percent water of crystallization. The ore varies greatly in the proportions of its constituents, and in color and consistency. Gibbsite, boehmite, and diaspore are the hydrated aluminum oxide minerals normally found in bauxite.
The average grade of bauxite ore used in the Bayer-Hall process has continually declined. In 1930, ore used in the U.S. averaged 60 percent alumina, and by 1963, the average was less than 50 percent alumina. Although it is anticipated that this average will decrease to about 35 percent alumina in the future, the process is limited generally to the use of bauxite ore high in aluminum content. Domestic reserves of such high grade are totally inadequate to meet current production requirements.
The difficulty in producing aluminum with respect to thermal processes does not reside in the formation of the aluminum via reduction of the alumina-bearing ores, but rather, in the recovery of aluminum in a substantially pure state.
Obtaining substantially pure aluminum from a carbothermic process by extremely high operating temperatures can lead to problems with respect to materials of construction.
The most common techniques in attempting to produce aluminum metal of a high degree of purity by direct thermal reduction treat the furnace product, conventionally containing 10-30 weight percent of aluminum carbide, by techniques such as fluxing the furnace product with metal salts to diminish the amount of aluminum carbide contamination.
The molten salts mix with the carbide so removed, and it is costly to remove the carbide from the salt so that the carbide can be recycled to the furnace. Without such recycle, the power consumption and furnace size become uneconomical in comparison with methods practiced commercially for making aluminum.
The furnace product contaminated with aluminum carbide can be heated with a molten slag containing substantial proportions of alumina to cause the alumina in the slag to react with the aluminum carbide in the furnace product, thereby diminishing the furnace product in aluminum carbide.
One mode can be described as the xe2x80x9creduction mode,xe2x80x9d and it involves reaction between alumina in the slag and aluminum carbide in the furnace product at reduction conditions so as to produce aluminum metal. One way of ascertaining operation in this mode is by detecting the evolution of carbon monoxide.
Another mode of reaction can be described as the xe2x80x9cextraction mode,xe2x80x9d and it involves reaction between the alumina in the slag and the aluminum carbide in the furnace product to produce non-metallic slag compounds such as aluminum tetraoxycarbide, as opposed to producing liquid aluminum. Such xe2x80x9cextraction modexe2x80x9d reactions occur at temperatures insufficient to cause reduction to produce additional aluminum and can occur without causing the evolution of carbon monoxide.
Temperatures of at least 2050xc2x0 C. are necessary for the xe2x80x9creduction modexe2x80x9d operations at reaction zone pressures of one atmosphere. At any given pressure, the temperature required for xe2x80x9creduction modexe2x80x9d operation increases as the level of aluminum carbide in the metal decreases. On the other hand, xe2x80x9cextraction modexe2x80x9d operations can take place below 2050xc2x0 C.
Slags containing calcium oxide can be used to lower the melting point. The majority of the slag does not have to be at the reduction temperature. It only has to be molten and at a high enough temperature to exist as a molten layer separate from the metal layer.
The slags used are those wherein the weight ratio of alumina to any aluminum carbide contained therein is at least 4:1.
In the production of aluminum, various methods are employed which utilize specific electric arc furnaces. In one method, a first furnace is charged with carbon in the form of coke along with aluminum oxycarbide slag. The furnace is heated to a temperature of about 2000xc2x0 C. resulting in the formation of aluminum carbide along with some aluminum and slag. The aluminum carbide is charged into the second furnace either in the molten state, or it is permitted first to cool after which it is crushed to a suitable size prior to charging. In the second furnace, the aluminum carbide is reacted with alumina to form aluminum which is recovered, and slag is returned to the first furnace.
Since the temperature required for the reduction of aluminum is relatively high, usually about 2000xc2x0 C., and since the heat transfer rate between bodies of disparate temperature is directly related to the temperature differences between the two bodies, it is advantageous from an energy conservation standpoint to retain any material being transported from a first reduction stage to a second stage in a high temperature ambient. In smelting processes using separate furnaces, considerable heat is lost, requiring the addition of this lost energy in the second furnace, whether intermediate products are delivered to the second furnace in a molten or in a solid, crushed state. Exposure of intermediate products to ambient air often results in undesirable chemical reactions.
Smelting processes employing two or three furnaces also have substantial manpower requirements. Because of the additional energy, equipment and manpower required, these processes are accompanied by unnecessarily high costs. Further, these methods result in a degree of physical loss of intermediate or final product because of repeated handling.
A practical and readily available source of aluminum contaminated with no more than about 5 weight percent of aluminum carbide can be achieved by the process and apparatus of the present invention.
The present invention provides a process for forming aluminum metal from the carbothermic direct reduction of alumina ore. An alumina ore is heated in the presence of carbon at an elevated temperature above about 2000xc2x0 C. to produce an aluminum metal. Aluminum metal or aluminum metal alloy scrap then is added as a solid coolant to reduce the temperature to about 900-1000xc2x0 C. and precipitate out aluminum carbide. The precipitated aluminum carbide is filtered, decanted, or fluxed with salt to form an aluminum metal produced by the carbothermic direct reduction of alumina ore and containing 5% by wt. or less aluminum carbide.
Scrap aluminum used in the aluminum production process of the invention can be obtained from several different sources, including consumer scrap, vehicle scrap, and plant scrap. Consumer scrap refers to aluminum alloy products, especially beverage and food cans, coated with various polymeric coatings. Vehicle scrap refers to aluminum alloy material obtained from junked motor vehicles. Plant scrap refers to waste material from aluminum manufacturing plants, such as defective sheet generated during drawing and ironing processes.
Recycled scrap aluminum alloy cans are compacted and baled. The cans are then reduced to shreds by a grinder, hammer mill or rotating knives so that they are in the form of small fragments of approximately 2-4 cm nominal diameter.
The shredded scrap is subjected to magnetic separation to remove iron and steel contaminants, and to gravity or cyclone separation to remove paper and other light weight contaminants. The cleaned scrap is then introduced into a delacquering furnace. Air heated to a temperature typically about 480-540xc2x0 C. is blown through the bed of scrap while it moves along on a steel conveyor belt. This temperature is sufficient to pyrolize organic matter but not to oxidize the aluminum alloy scrap.
Most aluminum alloy scrap is largely made up of recycled beverage cans containing about 25% by weight AA5182 can ends and about 75% by weight AA3004 can bodies. The typical compositions of these alloys are as follows, in weight %.
AA3004xe2x80x94Mg 0.9, Mn 1.0, Fe 0.45, Si 0.2, Ti 0.04, and Cu 0.18. AA5182xe2x80x94Mg 4.5, Mn 0.25, Fe 0.25, Si 0.12,Ti 0.05, and Cu 0.08.

Carbothermic aluminum production using scrap aluminum as a coolant