Microbial contamination is a primary cause of disease. Bacteria and viruses can be found in water, on food and on surfaces. Currently there are several different technologies available to eliminate and/or reduce microbial growth. However, the effectiveness of a particular method depends on the substance being treated and the type of microbe present. Additionally, chemical agents have deleterious effects on human health by themselves or via byproducts generated during the sanitization process.
Harsh chemicals, while capable of sanitizing surfaces, may have persistent smells or corrosive effects on the skin of the user, and would certainly not be acceptable for sanitizing foods.
U.S. Pat. No. 4,173,051 issued to Reid discloses a vegetable washer which uses paddles to agitate and clean the vegetables but has no provision to reduce bacteria.
U.S. Pat. No. 5,927,304 issued to Wen discloses a food washer which uses vibration to remove soil and ultraviolet light to kill bacteria.
There is a need for a sanitization system that allows the sanitization or disinfection with a multitude of applications. There exists a need for a safe method for the consumer to sanitize or disinfect water economically and on site with a single unit. Further, foods, vegetables, plants, and surfaces with which a number of people regularly come into contact would benefit from an effective sanitization system that does not employ dangerous chemical agents.
As used herein, the term sanitization refers to removal of at least a portion of an unwanted component from a substance, such as from a liquid, for example water, or from a solid, for example an object, a surface or a food product. The term purification, when used in reference to water or other liquids, is used synonymously herein with the term sanitization. As used herein, the term disinfection refers to a high level of sanitization of either a liquid or a solid. At the level of disinfection, the vast majority of live bacteria, viruses and/or other “infective” agents are removed from a liquid or a solid. Disinfection is not, however, used synonymously with the term sterilization, which is a high form of sanitization, implying a process more complete than disinfection.
Ozonificadon of Water.
Ozone (O3) is a strong oxidizing agent and is widely used as a disinfectant for food and water. Examples include U.S. Pat. No. 6,171,625 issued to Denvir et al., U.S. Pat. No. 6,200,618 issued to Smith et al., and U.S. Pat. No. 6,485,769 issued to Audy et al. However, these systems are large industrial systems and can not prevent recontamination of the food before delivery to the consumer.
U.S. Pat. No. 6,391,191 issued to Conrad discloses a domestic water treatment appliance which uses ozone to disinfect water.
U.S. Pat. No. 5,460,705 (Murphy et al.); U.S. Pat. No. 5,770,033 (Murphy et al.); and U.S. Pat. No. 5,989,407 (Andrews et al.) disclose devices capable of ozone evolution. The ozone so produced may be used to ozonify water.
Vortex-Venturi Devices.
Prior art documents of interest defining the field of vortex-venturi devices include U.S. Pat. No. 4,123,800 to Mazzei; U.S. Pat. No. 4,931,225 to Cheng; U.S. Pat. No. 5,061,406 to Cheng; U.S. Pat. No. 5,302,325 to Cheng; U.S. Pat. No. 5,863,128 to Mazzei; U.S. Pat. No. 5,880,378 to Behring; and U.S. Pat. No. 5,893,641 to Garcia.
The dispersion of one fluid into another is an important feature of a wide variety of operations. For example, gases are dispersed in liquids for numerous gas dissolving, gas-liquid reaction and gas stripping of dissolved gas applications. Gases are also mixed with gases. Liquids are also dispersed into other liquids for dilution or for liquid-liquid reactions. Examples include the mixing of disinfectants or fertilizers into water.
Many devices have been developed to disperse one fluid (an additive fluid) into another (the main fluid). The purpose of such devices is to bring a proportioned amount of one fluid into contact with another. In addition to this metering of fluid, it may be desired to have the additive fluid well-dissolved and distributed into the main fluid. If the additive fluid is a gas, the efficiency of dissolution is dependent on bubble size and motion. A vigorous motion of small bubbles will accelerate the dissolution of the gas. Vigorous movement will also assist the mixing of liquids.
For example, U.S. Pat. No. 4,931,225 issued to Cheng discloses a method and apparatus for dispersing a gas into a liquid. The gas is injected into the liquid upstream of a venturi. The gas-liquid mixture then flows through the venturi, is accelerated to supersonic speed and then decelerated to sub-sonic speed. The resulting shockwave breaks-up and disperses the gas bubbles.
U.S. Pat. No. 5,061,406 issued to Cheng discloses a method to disperse a gas into a liquid using an adjustable conical mixer to control the flow of the gas/liquid mixture to a venturi device. The conical mixer creates an annular opening in the venturi and controls the size of the opening. The gas is injected at supersonic speed upstream of the venturi. The gas/liquid mixture is accelerated to supersonic speed and subsequently decelerated to subsonic speed. The resulting shockwaves disperse the gas into the liquid.
U.S. Pat. No. 5,302,325 issued to Cheng discloses a method to disperse a gas into a liquid using a conical mixer. The mixer is placed into a cylindrical pipe resulting in an annular flow. The gas is injected at supersonic speed upstream of the mixer. As the liquid/gas mixture passes through the annular gap it is accelerated to supersonic speed and decelerated to subsonic speed with the resulting shock wave dispersing the gas. The annular flow causes a larger portion of the flow to be supersonic.
These devices have the problem that, while dispersing the gas, they also require additional energy in order to inject the gas.
Venturi based injector-mixers are also known. U.S. Pat. No. 4,123,800 issued to Mazzei discloses a venturi device comprising a constricting section, a throat section, and an expanding section. A plurality of ports are arranged angularly around the inside of the throat section and are interconnected to an annular chamber around the throat section.
U.S. Pat. No. 5,863,128 issued to Mazzei discloses a mixer-injector of the venturi type with a constricting portion, a throat section, and an expanding portion. The injection port is shaped as a continuous groove in the throat section. A plurality of twisting vanes in the constricting portion create a rotary motion to the outer portion of the flow and a plurality of straight vanes in the expanding portion remove some of the rotary motion for improved mixing.
U.S. Pat. No. 5,893,641 issued to Garcia discloses a venturi driven injector comprising a converging portion, a throat portion, and an expanding portion. The secondary (additive) fluid is injected via a plurality of ports arranged radially in a groove near the exit of the expanding portion. The secondary fluid is injected perpendicular to the flow of the main fluid.
Gas-Liquid Separators
The presence of entrained gasses in liquids is frequently encountered and in many cases is not desirable. These include boiler systems and hydraulic systems where the entrained gasses can cause noise or damage components. There are also systems where gasses are entrained purposely. These include the addition of nitrogen into liquids to strip out oxygen. In these systems there is a need to then remove both the entrained gas and the stripped gas and thus supply de-gassed liquid.
Another application of gas-liquid separators is for removing undissolved oxygen or ozone after these gasses have been entrained into water. Ozone is used to disinfect water. Water is capable of dissolving a certain amount of ozone, but most ozonation processes result in a certain amount of undissolved ozone gas. Undissolved ozone is dangerous to release directly into the atmosphere. A method is required to remove and treat the undissolved ozone gas formed as a result of such processes.
Oxidation Reduction Potential (ORP) Sensors.
Oxidation Reduction Potential (ORP) sensors are known in the art, for example, in U.S. Pat. No. 5,218,304 issued to Kinlen et al. and U.S. patent application No. 2003/0112012 by Mosley et al.
U.S. Pat. No. 5,218,304 issued to Kinlen et al. describes a sensor which may be immersed in a fluid to measure the pH and ORP of the fluid. The sensor describe uses a reference electrode of silver-silverchloride and an ORP sensing electrode of a noble metal such as gold or preferably platinum. Disadvantages of using such a reference electrode include cost considerations as well as manufacturing availability for a consumer appliance.
U.S. patent application No. 2003/0112012 by Mosley et al. describes a galvanic probe comprising of a sensor electrode and a reference electrode. The probe uses a reference electrode of a noble metal or antimony or bismuth, optionally an oxide or hydroxide thereof, and an oxidation reduction potential (ORP) sensing electrode of zinc or magnesium, optionally an oxide or hydroxide thereof. The disadvantage of using such a sensing electrode is the cost and manufacturing availability for a consumer appliance.
Sanitization Devices and Processes.
The following U.S. patents relate to disinfection and/or sanitization processes: U.S. Pat. No. 5,851,375 to Bodger, et al.; U.S. Pat. No. 6,379,628 to de Jong, et al.; U.S. Pat. No. 6,019,031 to Qin, et al., U.S. Pat. No. 5,048,404 to Bushnell, et al.; U.S. Pat. No. 5,690,978 to Yin, et al.; U.S. Pat. No. 6,093,432 to Mittal, et al.; and U.S. Pat. No. 6,086,932 to Gupta.
A popular household water filtration device is in the style of a pour-through pitcher. Typically, unfiltered water is added to a basin at the top of the device. Through the action of gravity, water percolates through a filtering media (usually consisting of granulated activated carbon) located between the basin and a collection reservoir. Filtered water is then dispensed from the collection reservoir for drinking. For the general public, gravity-controlled pitcher-type water filtration systems are cost effective. However purified the water produced may be, gravity filtration cannot introduce sanitizing gasses, such as ozone, into the purified water. Further, the purified water so formed may have little sanitizing effect on a surface with which it comes into contact, other than to mobilize or wash away bacteria, viruses or other unwanted substances.
Pour-through style device are unable to filter out and destroy smaller organisms and microbes. To facilitate the flow of water, the filtering media through which water is drawn needs to be of a porous nature. Because of this necessity, such devices do not purify or sanitize water as effectively as other water treatment devices. Part of this inefficiency is caused by a lack of additional purification steps, and reliance solely on the filter itself. Additionally, the filtering media or cartridge used in these pitcher-type pour-through filtering systems usually extends down into the collection reservoir, coming into contact with the filtered water. In some instances, this may be disadvantageous if other methods of liquid purification or sanitization are not employed. The porosity of the filter media may even promote infiltration, collection and growth of organisms. Thus, there is an increased potential for contamination of the filtered water when the filtering media extends into the collection reservoir.
U.S. Pat. No. 5,225,078 issued to Polasky et al., discloses a pour-through gravity-flow pitcher filter.
U.S. Pat. No. 6,103,114 issued to Tanner et al., cites a device which attempts to avoid cross contamination by the design of the spout, pour area and seal between the inner reservoir and the filtered water reservoir. However, the filter in this design still extends into the filtered water reservoir and is a potential source of contamination. U.S. Pat. No. 6,290,848 issued to Tanner et al., discloses a porous particulate filter for removing 99.95% of all 3-4 μm cryptosporidium and other protozoan cysts. U.S. Pat. No. 6,103,114, also issued to Tanner et al., describes a carafe-style filter device with a lip over the edge to prevent untreated water from mixing with treated water when pouring.
U.S. Pat. No. 6,391,191 issued to Conrad discloses a domestic water treatment appliance with a pump which uses ozone and a carbon block filter to disinfect water.
U.S. Pat. No. 6,238,552 issued to Shannon discloses a universal insert for a water purifier with a filter on top and bottom, and a guide for sliding the insert into a pitcher.
U.S. Pat. Nos. 4,969,996 and 4,306,971 issued to Hankammer disclose a column-like filter device extending into a collection reservoir. This design may potentially provide a source of contamination.
U.S. Pat. No. 6,405,875 issued to Cutler discloses a carafe-style filter device with an ion-exchange resin and carbon granules which removes 99.9% of all 3-4 μm particles. However, this device extends into filtered water reservoir and thus may be susceptible to contamination.
All references noted herein are incorporated by reference.
Thus, there is a need for improvements in sanitation devices that allow convenient access to purified, sanitized or disinfected water. There is also a need for a system that employs a plurality of technologies to achieve a high level of sanitization. Further a system that allows for purification of liquid in combination with other types of sanitization is desirable if objects, foods or surfaces are to be sanitized with the liquid so formed.
Additionally, there is also a need for an effective sanitization system capable of producing a liquid that can sanitize food, objects and surfaces.