AUTOMATED HUMIDIFICATION SYSTEM USING ANTIMICROBIAL AGENTS

Abstract: Method and systems for treating and/or protecting fresh and/or perishable food and floral products against festation by and proliferation of microorganisms, as well as reducing the presence and proliferation of microorganisms in the water supply (32) and internal workings of the misting and humidification system. The present invention relates to the use of one or more antimicrobial agents (34) in connection with misting and humidification systems (15, 31) that release water droplets or vapor into an environment (6) where fresh and/or perishable products, such as produce, meats, seafood, dairy products, plant products, and the like, are displayed, stored and/or transported.

Description: AUTOMATED HUMIDIFICATION SYSTEM USING ANTIMICROBIAL AGENTS Reference to Priority Applications This application claims priority from U.S. Provisional Patent Application No. 60/098,022, filed August 24, 1998, entitled, "Methods and Systems for Extending the Life of Food Products Using Antimicrobial Agents" and Provisional Patent Application No. 60/123,691, filed March 10, 1999, entitled, "Distribution of Antimicrobial Agents Through Humidification Systems." Field of the Invention The present invention relates to the use of one or more antimicrobial agents in connection with misting and humidification systems that release water droplets or vapor into an environment where fresh and/or perishable products, such as produce, meats, seafood, dairy products, plant products, and the like, are displayed and/or stored. Background of the Invention To maintain the freshness and desirable appearance of fresh foods, such as produce displayed in a supermarket, the produce is preferably kept in an environment that is cool and moist. Dehydration of fresh produce results in spoilage, an unattractive product appearance and reduced salability. Too much moisture may result in excess water retention, producing an undesirable appearance and increased susceptibility to bacterial or fungal growth. Several systems have been developed for hydrating fresh food items. Automated fresh produce hydration systems are described, for example, in the following U.S. Patents, which are incorporated herein by reference in their entireties: U.S. Patent 4,808,303; U.S. Patent 5,470,970; and U.S. Patent 5,651,502. These patents describe various approaches to hydrating fresh food. In all of them, water is conveyed to a plurality of spray heads designed to deliver moisture in the form of a mist or a fog to produce displayed below the spray heads. The systems are automated and controllable by timers, such that mist cycles of a specified duration may be programmed at specified intervals throughout the day and, if desired, around the clock. Similarly, storage and transport facilities for fresh or perishable products, such as produce, meat, seafood, dairy plant products, and the like, are generally provided with a humidification system. Such systems are automated and controllable to maintain a specified level of humidity in the storage or transport environment. One problem that is not addressed by conventional misting and humidification systems is the presence and proliferation of microbial organisms and the odors produced therefrom. Microbial contamination of fresh and/or perishable food items, such as fresh produce, may lead to spoilage and loss of a significant proportion of product. Furthermore, once a microbial infection is established, the microbial infection spreads rapidly. The methods and systems of the present invention are therefore directed to reducing the presence and proliferation of microbial organisms in environments in which fresh foods are displayed or otherwise exposed to the environment. Additionally, the misting nozzles and associated plumbing of conventional systems are prone to algal and microbial contamination, which is consequently spread to the food items below as the contaminated water is dispersed from the system. Accordingly, the methods and systems of the present invention are directed to reducing the presence and proliferation of microbial organisms within the plumbing and hardware of misting and humidification systems. Summary of the Invention The methods and systems of the present invention are suitable for use in connection with any type of misting and humidification operation. Misting and humidification systems of the present invention are used in connection with display, storage or transport of fresh and/or perishable items, including produce, meats, seafood, dairy, plant products, and the like. Methods and systems of the present invention are especially suitable for use in connection with the display storage or transport of fresh produce items, including fresh fruits and vegetables. Distribution of one or more antimicrobial agent through misting and humidification systems provides improved odor control, and additionally reduces the presence and proliferation of microorganisms in the environment, as well as reducing the presence and proliferation of microorganisms in the water supply and internal workings of the misting and humidification system, thereby reducing the bioburden transmitted to the food items during a misting or humidification cycle. Specifically, the present invention substantially reduces or eliminates infestation and proliferation of microrganisms within the plumbing of the misting or humidification system. The water supply contained within the misting and humidification systems is susceptible to contamination by various microbes, particularly algae, which in turn serves as a food source for further contamination by other microrganisms, resulting in extensive contamination of the water supply used to hydrate food items. The continued presence of an antimicrobial agent or agents throughout the misting or humidification system substantially reduces or eliminates infestation of the system. Furthermore, the reduction or elimination of microbial contamination prevents the occlusion of components and the resultant restriction of water flow caused by accumulated organic material. Traditional systems require periodic flushing and sanitizing to control internal contamination. Misting and humidification systems of various types and capacities are well known in the art. In such systems, an aqueous solution is distributed in the form of water droplets, mist or vapor during operation of the humidification or misting system. Such systems are generally automated to provide a selected level of mist or humidity and maintain an appropriate level of hydration in the storage or display environment. Control devices may be integrated with the misting and humidification systems to maintain a desired level of humidity or water volume per unit time. The methods and systems of the present invention involve the introduction and application of antimicrobial agents to fresh and/or perishable items through misting and humidification systems. Any antimicrobial that is non-toxic in the concentrations applied may be used. Suitable antimicrobial agents include the following: chlorine dioxide, sodium chlorite, acidified sodium chlorite, chlorous acid, stabilized chlorine dioxide, chlorine, hypochlorite compounds such as sodium hypochlorite, calcium hypochlorite and potassium hypochlorite, hypochlorous acid, peroxyacetic acid, hydrogen peroxide, ozone, organic acids or combinations thereof, such as acetic acid, citric acid, lactic acid, succinic acid, octanoic acid and decanoic acid, salts of organic acids such as sodium benzoate and sodium citrate, trisodium phosphate, chloramines, salts of isocyanuric acid, bromine and hypobromous acid. Chlorine dioxide, sodium chlorite, acidified sodium chlorite, chlorous acid, stabilized chlorine dioxide, chlorine, hypochlorite compounds such as sodium hypochlorite, calcium hypochlorite and potassium hypochlorite, and hypochlorous acid are preferred antimicrobial agents, and chlorine dioxide is an especially preferred antimicrobial agent. The methods and systems of the present invention may involve application of one or a combination of antimicrobial agents. A combination of broad spectrum antimicrobial agents may be required to effectively treat various organisms, such as, but not limited to, bacteria, protozoa, amoebae, algae and fungi. Additionally, the present invention is effective in the control of pathogenic organisms. In particular, the presence and proliferation of water borne pathogens, such as Legionella pnuemophilia, the etiological agent for Legionnaires disease, is transmitted to humans by aspiration of aerosolized water contaminated with the organism. Misting and humidification systems contaminated with Legionella pnuemophilia pose a potential public health risk by dispersing the pathogen in fine water mist or vapor in an environment frequented by humans. The methods and systems of the present invention substantially reduce or effectively eliminate the Legionella pnuemophilia bacterium, as well as protozoa and amoebae infected with the bacterium, from the misting and humidification systems, thereby reducing the public health risk. Antimicrobial agents that are soluble in aqueous solutions, or that can be applied in a gaseous form are preferred. In applications where the antimicrobial is soluble in aqueous solution, the antimicrobial agent may be introduced to the aqueous solution (e.g. water) supply for the misting or humidification system in an appropriate concentration that is non- toxic and that exerts an antimicrobial effect when applied by a misting or humidification system in a storage and or display environment. The antimicrobial agent(s) is preferably dissolved or suspended in the solution to provide an antimicrobial solution. Suitable mixing means may also be provided if mixing or agitation is required to dissolve or maintain the antimicrobial agent in solution. The antimicrobial solution is then transformed into droplets, mist or vapor, and applied to fresh and/or perishable items using a conventional humidification or misting system. Any of the prior art produce hydration and misting systems may be simply adapted, for example, to introduce an antimicrobial to a liquid tank or to the liquid feed stream, so that the solution applied as droplets, fine mist or vapor comprises an effective amount of an antimicrobial. An "effective amount" of any particular antimicrobial agent, or combination of antimicrobial agents, may be ascertained without undue experimentation. Additional non- toxic components may also be introduced into the humidification or misting system. For example, components that are known in the art to preserve or promote the freshness of fresh food items may also be applied through the misting or hydration system. The misting or humidification system may be operated in connection with a liquid purification system, such as a reverse osmosis system, carbon filter or deionizing unit, that removes undesirable contaminants from the aqueous solution prior to distribution through the misting or humidification system. According to one embodiment, the volume or concentration of antimicrobial agent(s) distributed to the environment through the humidification or misting system is adjustable to tailor the level of antimicrobial agent(s) applied to an environment depending upon the type of environment, the incidence or pervasiveness of a microbial population, the type of products being stored or displayed, and the like. Brief Description of the Figures The following drawings, in which like reference characters indicate like parts, are illustrative of embodiments of the invention and are not intended to limit the invention as encompassed by the claims forming part of the application. Figure 1 is a side view of a typical produce misting display case for the display of fresh produce that incorporates one embodiment of the present invention. Figure 2 is a side view of a typical produce misting display case for the display of fresh produce that incorporates another embodiment of the present invention. Figure 3 is a side view of a typical produce misting display case for the display of fresh produce that incorporates yet another embodiment of the present invention. Figure 4 is a front angled view of a typical humidification service case that incorporates an embodiment of the present invention. Figure 5 is a front angled view of a typical humidification service case that incorporates another embodiment of the present invention. Figure 6 is a front angled view of a typical service humidification case that incorporates yet another embodiment of the present invention. Detailed Description of the Invention The present invention provides methods and systems for substantially reducing and effectively eliminating infestation by and proliferation of microbes in storage, transport and display environments, thereby reducing spoilage of the stored, transported or displayed products, improving the shelf life and substantially eliminating unpleasant odors. As used herein, the term "antimicrobial agent(s)" means agents which effectively reduce the presence and proliferation of microorganisms, including, but not limited to bacteria, protozoa and fungi, and also inhibit microbial infestation. Suitable antimicrobial agents for use in methods and systems of the present invention include, but are not limited to, chlorine dioxide, sodium chlorite, acidified sodium chlorite, chlorous acid, stabilized chlorine dioxide, chlorine, hypochlorite compounds such as sodium hypochlorite, calcium hypochlorite and potassium hypochlorite, hypochlorous acid, peroxyacetic acid, hydrogen peroxide, ozone, organic acids or combinations thereof, such as acetic acid, citric acid, lactic acid, succinic acid, octanoic acid and decanoic acid, salts of organic acids such as sodium benzoate and sodium citrate, trisodium phosphate, chloramines, salts of isocyanuric acid, bromine and hypobromous acid. Chlorine dioxide, sodium chlorite, acidified sodium chlorite, chlorous acid, stabilized chlorine dioxide, chlorine, hypochlorite compounds such as sodium hypochlorite, calcium hypochlorite and potassium hypochlorite, and hypochlorous acid are preferred antimicrobial agents, and chlorine dioxide is an especially preferred antimicrobial agent. The methods and systems of the present invention may use one or more antimicrobial agents and combinations thereof. The individual and/or combined concentrations of the components should be sufficient to safely inhibit the proliferation of microorganisms. The effective concentration of the antimicrobial agent varies depending, in part, on the particular antimicrobial agent used. Table I provides a partial list of suitable concentration ranges and preferred concentration ranges. Table I. Additional information regarding suitable antimicrobial agents for use in the present invention and their relative strengths for determining a suitable concentration level can be found in Journal of Industrial Microbiology, Vol. 4, pp. 145-154 (1989), which is incorporated herein by reference in its entirety. From the information contained within this publication and/or with the routine knowledge of those practicing in this art, a suitable concentration of a selected antimicrobial agent may readily be determined. Furthermore, updated information pertaining to safe and efficacious concentration levels of specific antimicrobial agents is periodically provided by the Food and Drug Administration and the Environmental Protection. Agency. In a particularly preferred embodiment, the antimicrobial comprises an aqueous solution of chlorine dioxide having a concentration from about 0.01 to 200 ppm, preferably from about 0.1 to 20 ppm. Methods of preparation of aqueous solutions of chlorine dioxide are well known in the art. One synthesis process that is readily applicable to the present invention is based on the combination of two aqueous solutions: one solution contains a source of chlorite anions, and the other is acidic. The solution containing chlorite anions is usually a solution of sodium chlorite having a concentration of between about 100 ppm and about 5%, by weight, and having a pH of about 13. The acidic solution may contain any acid capable of providing a pH below about 8.5 after the solutions are mixed. Such acids include citric acid, lactic acid, hydrochloric acid, sulfuric acid, and dissolved carbon dioxide (i.e., sodium bicarbonate). The antimicrobial performance of the resultant solutions depends upon the degree to which the chlorite anions from the chlorite source solution are converted to free molecular chlorine dioxide in the solution, as chlorine dioxide is the effective agent for both antimicrobial and deodorization activity. In operation, the aqueous solution of chlorine dioxide may be prepared by placing an appropriate amount of sodium chlorite in the antimicrobial agent reservoir of the present misting and humidification systems, or other suitable vessel, diluted with sufficient water to achieve a desired end concentration and acidified as described above to provide a saturated or partially saturated aqueous solution of chlorine dioxide. The aqueous chlorine dioxide solution is introduced into the misting and humidification systems of the present invention. Display and service cases, as well as storage and transport facilities with misting or humidification systems are well known. In general, misting systems are used for the hydration of fresh or perishable food and use pressurized water systems to provide a fine spray, mist or vapor of water droplets. These systems serve to provide sufficient water to the items contained within the display case. Misting systems are controlled through various controller systems, such as integrated timers and solenoid valves, to dictate the frequency and duration of the misting cycles. The frequency and duration of the misting cycles is dependent on the individual requirements of the items being hydrated as well as environmental conditions. Humidification systems typically employ a combination of pressurized air and water to atomize water into a very fine mist, fog or vapor. The water particle size for humidification systems is generally smaller than that of misting systems. Humidification systems maintain a desired relative humidity in an enclosed or semi-enclosed environment used for the display, storage or transport of fresh and/or perishable items. These environments may be small service cases or vast storage facilities. Humidification systems may employ sensors to monitor the relative humidity of the environment and provide feedback to a central controller, which activates the humidification system as needed. The modified misting and humidification systems described herein may be incorporated into any of a variety of misting and humidification systems. In addition, the specific components for introducing antimicrobial agents may be retrofit into existing misting or humidification systems. As used herein, the term "misting systems" includes both misting and humidification systems for dispersing aqueous liquids in any water particle size range from droplets to a fine fog or vapor. Figure 1 illustrates a first embodiment of the inventive misting system incorporated into a representative display case. A typical produce display case 1 comprises a cabinet 2 with one or more shelves, a lower main shelf 3 and an optional upper half-shelf 4 for displaying produce. The display cabinet is configured so the produce is open and accessible to the public while concealing the majority of the misting components, for example the lower storage compartment 7 may house an optional filtration unit and a pressure tank. Often the display cases have a canopy section 6 which houses various components, including lighting fixtures 20, a controller system 19 and one or more misting bar conduits 16. One or more additional misting bar conduits 15 may be located on the underside of the upper half-shelf 4. Located along the length of the misting bar are specialized misting nozzles 17, 18 for dispersing fine water particles in the environment of the item displayed below. A standard water source line 32 providing water of sufficient pressure is connected by conventional means to a first inlet port 36 of a pump mechanism 31. In a preferred embodiment the pump mechanism possesses an electronic flow monitoring device to control the flow rate of the antimicrobial agent in order to maintain a desired final concentration of the antimicrobial agent(s). The electronic flow meter may, or may not be, integral with the pump mechanism, and be located in any suitable location. In addition, the pump mechanism is linked to a reservoir containing concentrated antimicrobial agent or agents 34 by a connection conduit 33. The connecting conduit 33 is connected to a second inlet port 38 of the pumping mechanism in any conventional manner. Exiting from an outlet port 37 of the pump mechanism is a water inlet line 8 connected to the first "T" fitting 12, which branches to the first 13 and second 14 delivery lines. Operationally, at the initiation of a misting cycle, a signal is sent from the controller 19 to the pumping mechanism 31 via a communication link 35, energizing the pumping mechanism to draw from the water source line 32 and the antimicrobial agent reservoir 34 at an appropriate flow rate to achieve the desired final concentration of antimicrobial agent. The system pressure continues to displace the diluted antimicrobial agent through the standard misting system. The diluted antimicrobial agent passes through the water inlet line 8 to a "T" connector 12 having a first 13 and second 14 delivery line. The first delivery line 13 transmits the diluted antimicrobial agent to a lower misting bar conduit 15 and to a plurality of nozzle assemblies 17. The second delivery line 14 transmits the diluted antimicrobial agent to an overhead misting bar conduit 16 and to a plurality of overhead nozzle assemblies 18. Upon activation of an appropriate activating device on the pumping mechanism a fine aqueous mist or fog comprising one or more antimicrobial agent(s) at an effective concentration is released from the nozzle assemblies to the environment of items located on the shelves below. The pumping mechanism may be any type suitable for introducing the concentrated antimicrobial agent or agents into the water stream, whether by mechanically injecting the concentrated antimicrobial agent in a pulsate or intermittent manner or by constant stream, so long as a desired final concentration of the antimicrobial agent(s) is obtained and reproducibly controlled. A preferred embodiment introduces antimicrobial agent(s) at intermittent misting or humidification cycles. The frequency of misting or humidification cycles of the diluted antimicrobial agent(s) in relation to misting or humidification cycles lacking antimicrobial agent(s) is adjusted to the particular requirements of the fresh and/or perishable items such that a safe and effective amount is delivered. A preferred embodiment utilizes a metering pump to accurately control the injection rate. The pumping mechanism may have an internal mixer, or alternatively have a mixer connected downstream before reaching the filtration unit to further facilitate even, consistent distribution of the antimicrobial agent(s). The pumping mechanism may operate using electronically controlled solenoid valves and switches or other comparable mechanisms. Control of the pumping mechanism's flow rate and consequent dilution of the antimicrobial agent(s) may be set at the central controller of the misting system or at controls integral with the pumping mechanism itself. Another embodiment of the present invention is illustrated in Fig. 2. This alternative embodiment is incorporated in a similar representative display case and misting system as previously described, and specific reference will therefore only be made to the particular components of this embodiment. A standard water source line 32 providing water of sufficient pressure is connected by conventional means to a first inlet port 56 of a eductor mechanism 50. The eductor mechanism may be one of a variety readily available on the market. A preferred embodiment utilizes a venturi type eductor, which accurately controls the feed rate of the concentrated antimicrobial agent or agents. In addition, the eductor mechanism is linked to a reservoir containing concentrated antimicrobial agent or agents 52 by a connection conduit 51. The connecting conduit 51 is connected to a second inlet port 57 of the eductor mechanism in any conventional manner. Exiting from an outlet port 58 of eductor mechanism 50 is a water inlet line 8 connected to the first "T" fitting 12, which branches to the first 13 and second 14 delivery lines. As water is drawn from the water source, a predetermined volume of concentrated antimicrobial agent is drawn from the antimicrobial agent reservoir and introduced into the water stream. The amount of antimicrobial agent(s) introduced into the water stream is predetermined based on the desired final concentration. The antimicrobial agent(s) may be introduced into the water stream by an appropriate eductor mechanism under the control of the central controller 19 through a communication link 53. In operation, a misting cycle is initiated by the controller 19 by energizing the eductor mechanism 50 to open at the inlet port 56 to permit pressurized water to flow through the eductor mechanism, thereby causing concentrated antimicrobial agent to be drawn into the water steam by venturi forces, or another comparable method of operation. The antimicrobial agent is sufficiently mixed to the desired concentration by the movement of the two streams. The diluted antimicrobial agent is further displaced through the misting system by continued water pressure for eventual distribution from the spray nozzles onto food items. Yet another embodiment of the present invention is illustrated in Fig. 3. This alternative embodiment is also incorporated into a representative display case and misting system previously described and therefore specific reference will only be made to the particular components of this embodiment. A standard water source line 32 providing water of sufficient pressure is connected by conventional means to a reservoir tank 70 containing antimicrobial agent or agents diluted to the desired final concentration. Exiting from the reservoir tank is a conduit connected to an inlet port 76 of a pumping mechanism 72. The pumping mechanism has a pump outlet line 73 connected to an outlet port 77 which connects to a water valve/connector 74. The water inlet line 8 from the misting system is connected in a conventional manner to the water valve/connector 74. During a misting cycle, a signal is sent from the central controller 19 through a communication link 75 to the pumping mechanism 72, whereby the pre-diluted antimicrobial agent is introduced into the misting system and eventually discharged as a fine mist or fog from the nozzle assemblies. Further embodiments of the present invention involve methods and systems for the introduction of antimicrobial agents in humidification systems. As illustrated in Fig. 4, a representative humidification service case 81 comprises a cabinet 82, the top portion forming a food storage surface 83 and the lower portion 84 providing storage area for humidification components. The food storage area of the service case is formed by a back wall 85, side partitions 86 and intermediate partitions 87 in combination with the food storage surface 83. Humidification systems commonly use specialized nozzle assemblies to atomize water with pressurized air into an extremely fine mist or fog to maintain a desired humidity in a microenvironment. As shown in Fig. 4, one humidification system may serve several food storage areas in the service case, requiring a series nozzle assemblies and complementary components. A typical humidification system comprises an air compressor 88 having primary air lines 89 connected in a conventional manner to a series of air valves 90. Secondary air lines 91 exit the air valves and connect in a typical fashion to a complementary series of air/water atomization nozzle assemblies 92. In addition to the air system, there is a water inlet line 8 having a number of branches, each of which connects to a complementary series of water regulators 93, which are connected to, or integral with, a complementary series of water valves 94. Exiting from the water valves are a series of water delivery lines 98 that are connected in a typical manner to a series of air/water atomization nozzle assemblies 92. To control the frequency and duration of humidification cycles, a controller 99 provides commands through a series of primary communication links 100 to solenoid valves 95, which have secondary communication links 96 to the air valves 90 and a communication links 97 to the water valves 94. A standard water source line 32 providing water of sufficient pressure is connected by conventional means to a first inlet port 36 of a pump mechanism 31. In addition, the pump mechanism is linked to a reservoir containing concentrated antimicrobial agent or agents 34 by a connection conduit 33. The connecting conduit 33 is connected to a second inlet port 38 of the pumping mechanism in any conventional manner. Exiting from an outlet port 37 of the pump mechanism is a water inlet line 8 connected to the series of water regulators 93. Operationally, at the initiation of a misting cycle, a signal is sent from the controller 99 to the pumping mechanism 31 via a communication link 35, energizing the pumping mechanism to draw from the water source line 32 and the antimicrobial agent reservoir 34 at an appropriate flow rate to achieve the desired final concentration of antimicrobial agent. The diluted antimicrobial agent is introduced into the humidification system at the same water source line as untreated water, thereby dovetailing into the humidification system without appreciably affecting the operational controls and systems. Yet another embodiment of the present invention is illustrated in Fig. 5. This alternative embodiment is incorporated into a similar representative service case and humidification system as previously described and therefore specific reference will only be made to the particular components of this embodiment. A standard water source line 32 providing water of sufficient pressure is connected by conventional means to a first inlet port 56 of eductor mechanism 50. In addition, the eductor mechanism is linked to a reservoir containing concentrated antimicrobial agent or agents 52 by a connection conduit 51. The connecting conduit 51 is connected to a second inlet port 57 of the eductor mechanism in any conventional manner. Exiting from an outlet port 58 of the pump mechanism is a water inlet line 8 connected to a series of water regulators 93 contained within the storage compartment 84. As water is drawn from the water source, a predetermined volume of concentrated antimicrobial agent is drawn from the antimicrobial agent reservoir and introduced into the water stream. The amount of antimicrobial agent(s) introduced into the water stream is predetermined based on the desired final concentration. The antimicrobial agent(s) may be introduced into the water stream by an appropriate eductor mechanism under the control of the central controller 99 through a communication link 53. In operation, a misting cycle is initiated by the controller 19 by energizing the eductor mechanism 50 to open at the inlet port 56 to permit pressurized water to flow through the eductor mechanism, thereby causing concentrated antimicrobial agent to be drawn into the water steam by venturi forces. The antimicrobial agent is sufficiently mixed to the desired concentration by the movement of the two streams. The diluted antimicrobial agent is further displaced through the humidification system by continued water pressure for eventual distribution from the spray nozzles 92 onto food items. Yet another embodiment of the present invention is illustrated in Fig. 6. As in previous embodiments, this alternative embodiment is also incorporated into a representative service case and humidification system previously described and therefore specific reference will only be made to the particular components of this embodiment. A standard water source line 32 providing water of sufficient pressure is connected by conventional means to a reservoir tank 70 containing antimicrobial agent or agents diluted to the desired final concentration. Exiting from the reservoir tank is a conduit connected to an inlet port 76 of a pumping mechanism 72. The pumping mechanism has a pump outlet line 73 connected to an outlet port 77 which connects to a water valve/connector 74. The water inlet line 8 from the humidification system is connected in a conventional manner to the water valve/connector 74. During a humidification cycle, a signal is sent from the central controller 99 through a communication link 75 to the pumping mechanism 72, whereby the pre-diluted antimicrobial agent is introduced into the humidification system and eventually discharged as a fine mist or fog from the nozzle assemblies. The frequency and duration of humidification cycles may be automated by employing sensors to monitor the relative humidity of the environment and provide feedback to the central controller. Alternatively, the frequency and duration of the humidification cycles may be input into the central controller and modified as necessary to maintain a desired relative humididty. The antimicrobial agent reservoir, internal lines or workings of the pumping and eductor mechanisms and any associated lines of the misting and humidification systems may be made of any suitable material, whether rigid or flexible, metallic, plastic or otherwise. The materials used should not appreciably react with the antimicrobial agents. The various embodiments of the present invention encompass misting and humidification systems having variations in the arrangement and type of components and accessories other than that described above. The present invention encompasses misting and humidification systems utilizing one or more solenoid valves located in-line between the pressure tank and the nozzle assemblies. The solenoid valves may or may not have an integrated timer to control the misting cycles. The duration and frequency of misting cycles may be controlled by adjusting the timing and flow rate controls at the central controller or at individual integrated timer-solenoid valves. The present invention encompasses misting systems having misting bars extending the width of the display case with a small diameter conduit and multiple branch water lines interconnected to the misting bar for uniform flow of water to all the nozzles. The present invention also encompasses misting systems having mist bars that are adjustable to direct the misting pattern, and also having mist tips connected directly into the misting bar with a ball check acting as a seal to prevent dripping. The present invention encompasses misting system utilizing auxiliary pressure pumps to increase system pressure, as well as systems utilizing various means of filtration, including reverse osmosis, deionization and various filament or carbon filters. The filtration systems should be located upstream of the systems for introducing antimicrobial agents into the misting and humidification systems. The systems of the present invention may also employ flow monitoring devices, whether electronic or mechanical. These flow monitoring systems serve to monitor the flow rates of the incoming water source and the antimicrobial agent(s) and provide feedback to the pumping mechanism to achieve accurate dilution of the antimicrobial agent(s) The present invention provides an improved misting and humidification system that is readily retrofit into existing systems. It is readily appreciated that several different versions of display or service cases may be presented and the above description is meant to be illustrative and not intended to limit the basic scope and spirit of the present invention. The present invention may also utilize drawback valves and miniature water regulators, as well as integrated mist valve and timer assemblies. While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to various changes and modifications in materials, components, structural arrangements, capacities and operational features, as well as additional embodiments without departing from the basic spirit and scope of the invention.

Claims: We Claim: 1. A misting system comprising: a liquid flow inlet conduit in liquid flow communication with at least one mist bar conduit, the at least one mist bar conduit in liquid flow communication with at least one misting nozzle adapted to disperse liquid in the form of fine water droplets, fine mist, or a fog; a reservoir containing at least one antimicrobial agent; and a mechanism for introducing the at least one antimicrobial agent into the liquid flow, whereby the liquid dispersed from the at least one misting nozzle in the form of fine water droplets, fine mist or a fog comprises at least one antimicrobial agent. 2. A misting system of Claim 1, wherein the reservoir contains at least one antimicrobial agent in a concentrated form. 3. A misting system of Claim 1, wherein the at least one antimicrobial agent comprises an agent selected from the group consisting of: chlorine dioxide, sodium chlorite, acidified sodium chlorite, chlorous acid, stabilized chlorine dioxide, chlorine, hypochlorite compounds, hypochlorous acid, peroxyacetic acid, hydrogen peroxide, ozone, acetic acid, citric acid, lactic acid, succinic acid, octanoic acid, decanoic acid, sodium benzoate, sodium citrate, trisodium phosphate, choramines, salts of isocyanuric acid, bromide and hypobromous acid. 4. A misting system of Claim 1, wherein the at least one antimicrobial agent comprises chlorine dioxide. 5. A misting system of Claim 1, additionally comprising a water filtration unit in liquid flow communication between the liquid flow inlet conduit and the at least one mist bar conduit. 6. A misting system of Claim 5, wherein the water filtration unit operates using reverse osmosis. 7. A misting system of Claim 1, wherein the mechanism for introducing the at least one antimicrobial agent into the liquid flow comprises a pump mechanism in liquid flow communication with the liquid flow inlet conduit and the reservoir. 8. A misting system of Claim 1, wherein the mechanism for introducing the at least one antimicrobial agent into the liquid flow comprises an eductor mechanism in liquid flow communication with the liquid flow inlet conduit and the reservoir. 9. A misting system of Claim 1, additionally comprising a control system capable of controlling liquid flow and the introduction of the at least one antimicrobial agent into the liquid flow. 10. A misting system of Claim 9, wherein the control system provides controllable, intermittent dispersal of liquid comprising an antimicrobial agent from the at least one misting nozzle. 11. A misting system of Claim 9, wherein the control system includes a programmable timer. 12. A misting system of Claim 9, wherein the control system is programmable to operate the misting system to maintain a predetermined humidity. 13. A misting system of Claim 9, wherein the control system is in communication with at least one remote humidification sensor and is responsive to data provided by the at least one remote humidification sensor to maintain a predetermined humidity. 14. A misting system of Claim 1, additionally comprising a liquid flow meter for measuring the liquid flow in the liquid flow inlet conduit, and for providing data regarding the liquid flow to the mechanism for introducing the at least one antimicrobial agent into the liquid flow. 15. A misting system of Claim 1, additionally comprising a metering valve in communication with the reservoir containing the at least one antimicrobial agent and the liquid flow inlet conduit, the metering valve providing controllable introduction of the at least one antimicrobial agent to the liquid flow inlet. 16. In misting systems comprising a water inlet conduit in liquid flow communication with at least one nozzle assembly whereby the misting and humidification system distributes mist in the form of fine water droplets, fine mist or a fog, the improvement comprising introducing at least one antimicrobial agent to provide distribution of an antimicrobial agent in the form of fine water droplets, fine mist or a fog.

Inventors: AAMODT JAMES, DAVIS WENDELL R, KENNEDY JOHNNY DALE, RINGO JAMES PARKER, AAMODT, JAMES, DAVIS, WENDELL, R., KENNEDY, JOHNNY, DALE, RINGO, JAMES, PARKER
Applicants: RAYTEC CORP, RAYTEC CORPORATION
Application year: 1999
Main classification: B01F3
IPC codes: B01F3, B01F5, F24F6