Abstract:
A compact, efficient, easy-to-maintain enclosable cabinet for sanitizing a liquid flowing along a cascade within a cabinet body, having a cabinet body, a plurality of troughs directing the liquid along a predetermined path including a cascade within the cabinet body and one or more sanitizing radiation sources for subjecting the liquid to a sanitizing radiation for a predetermined time while flowing along the predetermined path, whereby the liquid is subject to sufficient sanitizing radiation for a predetermined level of sanitization. The sanitizing radiation sources are assemblies having a UV light source, a UV light shield located between the UV light source and the liquid and a rigid internal reflector shield located between the UV light source and the UV light shield.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to sanitation of a liquid and more particularly pertains to compact, efficient devices used for irradiation of liquids such as those used in foods and food processing. The present invention also relates to liquids sanitized by such devices.  
           [0003]    2. Description of Related Art  
           [0004]    Food sanitation is a growing concern in the world. More and more aggressive disease causing agents are discovered every year. Moreover, an increasing number of people are made ill each year by eating contaminated foods. Also, the numbers of foods linked to food-caused illnesses continues to increase. Nonetheless, the desire for safer foods is higher than ever. In fact, state and federal jurisdictions are requiring that businesses use the most efficacious food safety and sanitation practices.  
           [0005]    Efficient use of modern sanitation techniques decreases the cost of applying them. These savings, when passed to the consumer, mean the consumers spend less on the processed foods. Also, efficient sanitizing techniques can allow more food to be processed in a smaller amount of space. Thus smaller facilities may compete with larger ones, thereby increasing competition between processors and also lowering prices to consumers. In addition, facilities that use less-safe processing techniques may be easily retrofit to install an efficient apparatus. Also, the modularity of a new sanitizing apparatus makes it easy to manufacture and easy to replace parts for the apparatus.  
           [0006]    Sanitizing radiation allows a highly controllable application of organism-killing radiation to foods and food additives. The use of sanitizing radiation in the food industry in general is well known in the prior art, and has been used in a variety of forms, including gamma ray radiation, ultraviolet (UV) light and infrared radiation.  
           [0007]    For example, it is well known that the use of gamma radiation and UV radiation has been used in some countries for the sterilization of spices and animal feeds. However, over-use of ultraviolet radiation may cause undesirable chemical reactions with a food or food additive, which can cause the food or food additive to obtain undesirable flavors or textures. Also, various vitamins and proteins may be altered or destroyed through being subjected to too much radiation, reducing the food value of the treated product.  
           [0008]    Traditional methods of irradiating liquid foods and food additives used an unnecessary amount of space in a food processing facility. They have long conveyors or hard-to-reach pipelines. For example, U.S. Pat. No. 6,150,663 to Rosenthal teaches a system incorporating a pair of stainless steel cones placed end-to-end and jacketed with steel to treat a liquid flowing through a pipeline. The entire system is linear in flow and an inefficient use of space. Moreover, in the prior art different systems are used for different processes. The lack of a modular system makes utilization the sanitizing radiation difficult to apply or manufacture on a large scale, or to retrofit into an existing system.  
           [0009]    There is no system designed with modularity in mind, to suit different processes properly, or to provide easy replacement of component parts. There is no system wherein the radiation sources as well as the paths for the liquid to be sanitized are both optimized for radiation treatment and are highly modular in design. There is no system that treats liquid as a thin film, governed principally by its surface tension, thereby allowing sanitization of fluids even with a relatively high opacity. There is no system that is easy to assemble, clean, maintain and disassemble. There is no system using sanitizing radiation which is compact and enclosable, so high levels of the radiation may be used in a small amount of space and still be safe for operators. There is no system which takes advantage of the flowing characteristics of a liquid to form a cascade in a sanitization process, thereby reducing the length that another apparatus providing an equivalent amount of sterilizing radiation would have to take up.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention is a compact, efficient, easy-to-maintain enclosable apparatus for sanitizing a liquid flowing along a cascade within a cabinet body, having means for directing the liquid along a predetermined path within the cabinet body and means for subjecting the liquid to a sanitizing radiation for a predetermined time while flowing along the predetermined path, whereby the liquid is subject to sufficient sanitizing radiation for a predetermined level of sanitization. In one embodiment, the means for directing the liquid comprises a plurality of downward sloping irradiation trays whereby liquid travels from one irradiation tray to another irradiation tray. Preferably, the irradiation trays have one or more elements adapted for increasing the turbulent circulation of the liquid, and the liquid is diffused before the liquid reaches an irradiation tray so that the liquid flows generally the width of the irradiation tray. The cabinet body includes an ingress and an egress.  
           [0011]    In an alternative embodiment, each irradiation tray comprises a plurality of elements adapted for increasing circulation of the liquid. In another embodiment, the means for subjecting the liquid to a sanitizing radiation comprises one or more irradiation assemblies in optical contact with the surface of the liquid. In yet another embodiment, the irradiation assembly comprises a UV light source and a UV light shield located between the UV light source and the liquid. In still another embodiment, the irradiation assembly further comprises a rigid reflector shield located between the UV light source and the UV light shield. In yet another embodiment, the reflector shield provides resistance to ease the attachment of the irradiation assembly to the cabinet body and strength to the irradiation assembly to resist damage during maintenance activity including hosing.  
           [0012]    In another embodiment, the means for diffusing includes one or more diffusing trays, each diffusing tray including several voids through the bottom surface. In still another embodiment, the irradiation trays have one or more down pipes at a downstream position. The diffusing trays further may include a generally c-shaped splash guard piece, and the down pipe of an irradiation tray above the diffusing tray is in complementary contact with the splash guard. The diffusing tray and the irradiation tray may be easily removable.  
           [0013]    In yet another embodiment, the egress includes a sloping bottom interior surface of the cabinet body toward a drain pipe in gravity flow connection with the sloping bottom. In still another embodiment, the amount of radiation exposure to the liquid is a function of the opacity of the liquid, the rate of flow of the liquid, the intensity of the source of the sanitizing radiation, the distance between the sanitizing radiation and the liquid, the time the liquid spends under the sanitizing radiation.  
           [0014]    In still another embodiment, the invention is an irradiation assembly for use in irradiating a liquid flowing in a cascade within an enclosable cabinet, comprising a UV light source. a UV light shield located between the UV light source and the liquid and a rigid internal reflector shield located between the UV light source and the UV light shield. In yet another embodiment, the assembly has an endcap located on each end of the UV light shield for attachment of the assembly within the interior of the cabinet. The endcap may further include a rigid sheath having threads, located around the perimeter of the UV light shield, an endpiece having threads which are complementary to those on the sheath located on the exterior of the cabinet; and a compressive gasket, whereby engagement of the endpiece with the sheath generally seals the assembly to the interior of the cabinet.  
           [0015]    In yet still another embodiment, the invention is a compact, efficient, easy-to-maintain enclosable cabinet for sanitizing a liquid having a cabinet body, a plurality of troughs directing the liquid along a predetermined path including a cascade within the cabinet body; and one or more sanitizing radiation sources for subjecting the liquid to a sanitizing radiation for a predetermined time while flowing along the predetermined path, whereby the liquid is subject to sufficient sanitizing radiation for a predetermined level of sanitization. At least one trough preferably is an irradiation tray oriented so the liquid flows from a first end to a second end with a down pipe located at the second end and a diffuser at the first end. The sanitizing radiation source is an array of UV light sources. Preferably, the sanitizing radiation source is at least two horizontal rows of four UV light sources. In still another embodiment, the apparatus is modular in design.  
           [0016]    The invention also comprises a method for sanitizing a liquid within a compact, efficient, easy-to-maintain enclosable apparatus, comprising the steps of providing an ingress for the liquid into a cabinet body, directing the liquid along a plurality of troughs so that the liquid travels along a predetermined vertical and horizontal path within the cabinet body; and subjecting the liquid to one or more sanitizing radiation sources for a predetermined time while flowing along the predetermined path, whereby the liquid is subject to sufficient sanitizing radiation for a predetermined level of sanitization. In another embodiment, the method includes the step of providing an egress for the liquid after exposure to the sanitizing radiation.  
           [0017]    It is an object of this invention to provide an apparatus designed with modularity in mind, to suit the processing of different foods or food additives, thereby making it economically beneficial to manufacture in assembly line fashion.  
           [0018]    It is also an object of this invention to provide an apparatus in which the radiation sources as well as the paths for the liquid to be sanitized are optimized for radiation treatment and are highly modular in design.  
           [0019]    It is also an object of this invention to provide a system for sanitizing a liquid that treats the liquid as a thin film, governed principally by its surface tension, thereby allowing sanitization of the liquid even having a relatively high opacity with regard to the sanitizing radiation.  
           [0020]    It is also an object of this invention to provide a compact apparatus for sanitizing a liquid that is easy to assemble, clean, maintain and disassemble.  
           [0021]    It is also an object of the invention to provide an apparatus using sanitizing radiation, which is compact and enclosable, so high levels of the radiation may be used in a small amount of space and still be safe for operators.  
           [0022]    It is also an object of this invention to provide an apparatus which takes advantage of the flowing characteristics of a liquid to form a cascade in a sanitization process, thereby reducing the amount of mechanical parts or pumping action required.  
           [0023]    It is also an object of the invention to reduce the horizontal length necessary to irradiate a liquid.  
           [0024]    In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.  
           [0025]    In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]    [0026]FIG. 1 a  is a front view of the preferred embodiment of the invention with the cabinet doors shut.  
         [0027]    [0027]FIG. 1 b  is a front view of the preferred embodiment of the invention with the cabinet doors removed.  
         [0028]    [0028]FIG. 2 is a left side view of the invention.  
         [0029]    [0029]FIG. 3 is a right side view of the invention.  
         [0030]    [0030]FIG. 4 is a detail cut-away view of the front right side of the invention.  
         [0031]    [0031]FIG. 5 a  is a top view of the bottom portion of the cabinet of the invention.  
         [0032]    [0032]FIG. 5 b  is a side view of the bottom portion of the cabinet of the invention.  
         [0033]    [0033]FIG. 6 is a top view of an irradiation tray of the invention.  
         [0034]    [0034]FIG. 7 is a side view of an irradiation tray of the invention.  
         [0035]    [0035]FIG. 8 a  is a top view of a diffuser tray of the invention.  
         [0036]    [0036]FIG. 8 b  is an end view of a diffuser tray of the invention.  
         [0037]    [0037]FIG. 8 c  is a side view of a diffuser tray of the invention.  
         [0038]    [0038]FIG. 9 a  is a top view of a c-shaped splash guard of the invention.  
         [0039]    [0039]FIG. 9 b  is a side view of a c-shaped splash guard of the invention.  
         [0040]    [0040]FIG. 10 is a top view of diffuser including a splash guard.  
         [0041]    [0041]FIG. 11 a  is a top view of a diffuser and irradiation tray assembly.  
         [0042]    [0042]FIG. 11 b  is a side view of a diffuser and right-running irradiation tray assembly.  
         [0043]    [0043]FIG. 11 c  is a side view of a diffuser and left-running irradiation tray assembly.  
         [0044]    [0044]FIG. 12 is a side view of a sanitizing radiation source of the invention.  
         [0045]    [0045]FIG. 13 is a side view of a reflecting tube of the invention.  
         [0046]    [0046]FIG. 14 is a side view of a shield of the invention.  
         [0047]    [0047]FIG. 15 is a side view of a sanitizing radiation assembly of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0048]    The present invention is a compact, efficient, easy-to-maintain enclosable apparatus for sanitizing a liquid, in a cascade, shown generally in FIGS. 1 a  and  1   b  as  10 . FIG. 1 a  illustrates the exterior of the apparatus  10 , showing the cabinet body  12  front side  14  with its doors  16 ,  18  shut. It is preferred that the doors  16 ,  18  swing open on hinges  26 , and a handle  82  is used to open and shut the doors  16 ,  18 . A latch  28  or other securing means prevents the doors  16 ,  18  from accidentally being opened. It is also preferred that the apparatus  10  has a sensor  80  as shown in FIG. 1 b,  to halt liquid flow and/or sanitizing radiation when the doors  16 ,  18  are opened.  
         [0049]    The cabinet body  12  includes an ingress  20  for liquids to enter the cabinet body  12  located generally at the top of the cabinet body. An egress  22  for liquids after sanitation is located generally at the bottom of the apparatus  10 . As shown in FIGS. 1 a,    1   b  and  2 , it is preferred that the apparatus stands in legs  24 . It is also preferred that the bottom portion  32  of the cabinet body  12 , shown in FIGS. 5 a  and  5   b,  is contoured so that liquid contacting the top surface  30  of the bottom portion  32  is directed generally toward the egress  22 . However, other configurations are contemplated and may be preferred, depending upon the usage and placement of the apparatus  10  by the operator.  
         [0050]    The interior configuration of the apparatus  10  is shown in FIGS. 1 b  and  4 . As shown, within the apparatus  10  the liquid to be sanitized is diffused and then routed across radiation sources for sanitation in a cascade. In the preferred embodiment, the apparatus  10  includes a plurality of diffusers  34  located in fluid connection with irradiation trays  36 . The preferred embodiment of the diffuser  34  and irradiation tray  36  are shown in detail in FIGS.  6 - 11 . A diffuser  34  is illustrated in FIGS.  8 - 10 , and comprise a diffuser tray, shown in FIGS. 8 a - 8   c  and a generally c-shaped splash guard  40 , shown in FIGS. 9 a - 9   b.  It is preferred that the splash guard  40  is welded to the diffuser tray  38  to form diffuser  34 , as shown in FIG. 10. However, other means for attachment for the splash guard are known in the art and may be used. The diffusers  34  have voids  42  to diffuse liquid within the apparatus  10  before it flows down into irradiation tray  36 . The diffuser tray height  50 , shown in FIG. 8 c,  as well as the shape, size and number of voids  42  may be optimized for dispersion of the liquid, and depend upon the volume of the liquid flowing as well as its thickness or viscosity. In the preferred embodiment, the diffuser  34  further comprises flanges  44  to allow the diffuser  34  to be held in place by a diffuser support  46  and a lip  48  located on the irradiation tray  36 , as illustrated in FIGS. 6 and 11. The diffuser  34  is located so that liquid within the apparatus  10  is diffused by the diffuser  42  and flows through the voids  42  into an irradiation tray  34  below it, for processing and/or sanitization.  
         [0051]    The irradiation tray  36  is illustrated in FIGS.  6 - 7 . It includes elements  52  to optimize the turbulent flow of the liquid being sanitized. It also comprises a place for holding a diffuser  34  on one side, and a place for outflow of the liquid, such as a down pipe  54 , on the other side. Preferably, there is a temporary fill area  56  which allows liquid to collect above the down pipe  54  after passing over the elements  52 , thereby reducing the risk of splashing within the apparatus  10 . In the preferred embodiment, the down pipe  54  fits complementarily with the recess of the splash guard  40  of an irradiation tray  36  below it, as shown generally in FIGS. 1 b  and  4 . Thus, the irradiation trays  36  are both right-flowing and left-flowing in design. A right-flowing irradiation tray  36  with diffuser  42  is shown in FIGS. 11 a  and  11   b,  and a left-flowing irradiation tray  36  with diffuser  42  is shown in FIG. 11 c.    
         [0052]    Over each irradiation tray  36  is at least one sanitizing radiation source. In the preferred embodiment, four (4) sanitizing radiation sources are used for each irradiation tray  36 . The preferred embodiment of a radiation source is a bulb and assembly as illustrated in FIGS.  12 - 15 . The bulb is preferred to be a low-pressure mercury vapor UV light  58 , capable of emitting UV light of approximately 254 nm. It is also preferred that the UV light have its electrical connectors  70  on one side rather than both sides. While the right side is illustrated and discussed, they may alternatively be found on the left side. It is also preferred that the bulbs are made from shatterproof glass.  
         [0053]    Preferably, around the light  58  is a reflector tube  60 . The tube  60  has a highly reflective interior surface, so the radiation from the radiation source  58  is used more efficiently onto the liquid being sanitized by the apparatus  10 . Also, it is preferred that the tube  60  be rigid to help in securing the connection of the sanitizing radiation source to the interior of the cabinet body  12 . The reflecting tube  60  is positioned so that radiation emitted away from the liquid is redirected generally toward the liquid. It is also preferred that the reflecting tube  60  is of a length designed so that radiation to the liquid from the sanitizing radiation source is not obstructed. The reflecting tube is generally cylindrical; however, the interior geometry may be altered to optimize reflection of the sanitizing radiation onto the liquid.  
         [0054]    The preferred material for the tube  60  is aluminum; however, other metals may be used, or a reflective coating on the interior surface of a rigid, generally cylindrical piece. Around the tube  60  is preferably a shield  62 , to shield the liquid from any material that may possibly fall into the liquid if the radiation source breaks. Preferably, the shield  62  is a transparent, generally flexible cylinder made from fluorocarbon. However, other materials may be used.  
         [0055]    In the preferred embodiment, as shown in FIG. 15, on each end of the shield  62  is an endcap fitting  64 . Each endcap fitting  64  is generally cylindrical and allows each end of the shield  62  to fit at least partway within it. Around each endcap fitting  64  is a means for forming a compressive seal, such as a gasket  66 . On the far end of each endcap fitting  64  is an endcap. A closed endcap  68  is preferred for the end of the UV light  58  that has no electrical connectors  70  to protect the radiation sources and to reduce radiation escaping from the apparatus  10 . An open endcap  72  is preferred for the end of the UV light  58  that has electrical connectors  70  to facilitate access to wiring (not shown) of the UV light  58 , for example to elements such as ballast circuits  74  attached to the outer surface of the cabinet body  12 . Ballast circuits  74  attached to the apparatus  10  are illustrated in FIGS. 1 a,    1   b,    3  and  4 . In the preferred embodiment, the endcap fittings  64  and the endcaps  68 ,  72  have complementary threads, so that screwing the endcaps  68 ,  72  onto the endcap fittings  64  compresses the compressive seal  66 . The UV light assembly  84 , including endcaps  68 ,  72  is shown in FIG. 15.  
         [0056]    UV light assemblies  84  are fit onto the cabinet body  12  as shown in FIGS. 1 b  and  4 . Compression of the gasket  66  around the endcap fitting  64  helps seal the sanitizing radiation source into the cabinet  12 . The rigid tube  60  helps provide resistance for screwing the endcaps  68 ,  72  onto the endcap fittings  64 , to form the compressive seal. The rigid tube  60  also forms a support for the shield  62  so that the shield  62  goes not contact the UV light  58  during maintenance, thereby causing the UV light  58  to break.  
         [0057]    As shown in FIG. 1 b,  the irradiation trays  36  are placed within the cabinet body  12 , on support brackets  76 . The support brackets  76  are preferably offset so that fluid within an irradiation tray  36  flows downward towards the down pipe  54 . It is preferred that the radiation trays  36  are approximately one quarter inch offset from level to facilitate liquid flow. Alternatively, the brackets  76  may hold the irradiation trays  36  level, while the irradiation trays themselves have a downhill gradient toward the down pipe  54 . The irradiation trays  36  within the cabinet body  12  are aligned with right-flowing irradiation trays  36  alternating with left-flowing irradiation trays  36 , as shown generally in FIG. 1 b  to form a cascade. Preferably, the first irradiation tray  36  in the cascade is fitted so the splash guard  40  of the diffuser  34  is placed under the ingress  20 . The final irradiation tray  36  in the cascade permits the fluid to pass from the down pipe  54  to the egress  22 .  
         [0058]    In the preferred embodiment, as shown in FIGS. 1 b  and  2 , the apparatus has five (5) alternating irradiation trays  36 . Each irradiation tray  36  is irradiated by four (4) radiation sources in radiation assemblies  84 . The assemblies  84  are approximately four (4) inches above the flowing liquid.  
         [0059]    As shown in FIGS. 3 and 4, it is preferred that ballast circuits  74  for the radiation sources, when needed, are attached to the outside of the cabinet body  12 . It is preferred to have them on one side, closest to the electrical connectors  70  of the radiation sources.  
         [0060]    Liquid is sanitized by the apparatus  10  as follows. Liquid enters the cabinet body  12  through the ingress  20  into a first irradiation tray  36 . The ingress  20  preferably includes an ingress pipe  78  which fits complementarily to a splash guard  40  on the first diffuser  34  on the first irradiation tray  36 . The liquid is diffused by a diffuser  34 , and flows down the irradiation tray  36 . The liquid is roiled by elements  52  on the irradiation tray  36 , thereby insuring sanitizing radiation through the liquid. As the liquid flows along the irradiation trays  36 , it is subjected to sanitizing radiation from above, preferably using low-pressure mercury UV light sources. A generally cylindrical reflector tube  60  preferably focuses the radiation on the liquid, and a shield  62  preferably protects the liquid and the interior of the apparatus from materials if the light source were to break. The liquid flows down to a down pipe  54 , complementarily fit into a splash guard  40  of an irradiation tray facing in the opposite direction. The liquid continues to flow down this irradiation tray  36  to successive irradiation trays  36  in cascade fashion, until the liquid has sufficiently been sanitized by the irradiation assemblies  84 . The amount of radiation exposure to the liquid is optimized as a function of the opacity of the liquid, the rate of flow of the liquid, the intensity of the source of the sanitizing radiation, the distance between the sanitizing radiation and the liquid, the time the liquid spends under the sanitizing radiation. In the preferred embodiment, the liquid spends approximately one to 1.5 seconds per irradiation tray  36 . It is preferred that the liquid be exposed to 40 mW-seconds of sanitizing radiation. The liquid then flows from the last irradiation tray  36  to an egress  22  in the cabinet body  12 .  
         [0061]    The cabinet body  12  and the components are easy to maintain. IT is preferred that the elements touching the liquid, and the cabinet body, be made of an easy to maintain food sanitary material, such as stainless steel. As described, the diffusers  34  and the irradiation trays  36  are easily removable from the cabinet body. Also, the sanitizing radiation sources such as the UV lights  58  as described in the preferred embodiment are easy to replace, simply by removing one or more of the endcaps  68 ,  72  to the approximate assembly  84  and removing the necessary radiation source. Furthermore, the wiring of the radiation sources is easy to access, since the open endcaps  72  allow access to the wiring, even when the apparatus  10  is in operation.  
         [0062]    In an alternative embodiment, the apparatus includes a supply pump, flow meter and a control valve, such as a butterfly valve in place upstream from the ingress  20 . In another alternative embodiment, a discharge pump, control valve and flow meter are in place down stream from the egress  22 , as shown generally in FIGS. 1 a,    1   b  and  2 . The cabinet body  12  may also have overflow openings and controls within the cabinet body above the egress  22 .  
         [0063]    The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art.  
         [0064]    The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art.