Abstract:
A retort system includes a vessel including a crate receiving volume. A crate is located in the crate receiving volume, the crate including sides defining a product receiving volume. A plurality of tubes extend between opposite sides and through the product receiving volume. The tubes include nozzles distributed along their lengths for ejecting a heated fluid during a heating operation within the retort.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to U.S. Provisional Application No. 60/798,988, entitled “Heat Transfer System for Retorts or the Like, and Method Therefore,” filed May 8, 2006, and U.S. Provisional Application No. 60/798,980, entitled “Sonic System for Enhancing Heat Transfer in a Retort or the Like,” filed May 8, 2006, the contents of both of which are hereby incorporated by reference as if fully set forth herein. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates to a method and apparatus for thermally treating foods, pharmaceuticals, and other products, and particularly to a system for enhancing heat transfer in a thermal treatment process (which may include sterilization, cooking, etc) involving a retort, autoclave, sterilizer or the like.  
       BACKGROUND  
       [0003]     To sterilize many foods, pharmaceuticals and other products, to make them “shelf-stable,” these products must be subjected to a sterilization method by heating the food, in its sealed container to a predetermined temperature. The product is held at this temperature for a product specific duration. This process is commonly referred to as an autoclave process, retort process or a sterilization process.  
         [0004]     Prior patents have contemplated vibrating, shaking, rotating, or repositioning the product within the retort during the sterilization procedure, but in large batches of product which have been densely loaded in baskets, trays, racks, and such, there exists a problem providing even thermal distribution to all product during the treatment process.  
         [0005]     Particularly, with baskets in an immersion-type retort which are subject to extreme agitation so as to lessen the batch time, the product situated along the outer periphery of the batch may receive more thermal energy from the surrounding fluid than the product in the core of the batch, resulting in disproportionate thermal transfer. This is because the fluid surrounding the batch is thermally affected as it contacts the outer product forming the batch, and is further affected as it migrates to the core of the product.  
       SUMMARY  
       [0006]     In an aspect, a retort system includes a vessel including a crate receiving volume. A crate is located in the crate receiving volume, the crate including sides defining a product receiving volume. A plurality of tubes extend between opposite sides and through the product receiving volume. The tubes include nozzles distributed along their lengths for ejecting a heated fluid during a heating operation within the retort.  
         [0007]     In another aspect, a crate is sized and configured for placement within a retort. The crate is capable of holding product for a heating process within the retort. The crate includes sides defining a product receiving volume. A plurality of tubes extend between opposite sides and through the product receiving volume. The tubes include nozzles distributed along their lengths for ejecting a heated fluid during a heating operation within the retort.  
         [0008]     In another aspect, a method of processing products in a retort system is provided. The method includes locating a crate within a crate receiving volume of a vessel. Products are heated within a product receiving volume of the crate by delivering heated fluid through a plurality of tubes extending between opposite sides of the crate and through the product receiving volume. The tubes include nozzles distributed along their lengths ejecting a heated fluid during a heating operation within the retort.  
         [0009]     In yet another aspect, a method of thermally treating a product within a retort is provided. The method includes, placing the product within a vessel of the retort. A heat transfer medium is placed in contact with the product. Sonic or ultrasonic energy is delivered to the product through the heat transfer medium.  
         [0010]     The present system can provide a means of evenly distributing the heat transfer fluid throughout the basket, from its core to the outer area, uniformly. Such a system can speed up heat transfer in an immersion retort by minimizing heat loss as it migrates toward the center of the batch, even in densely packed batches. The system may utilize conic or ultrasonic energy within a retort enclosure during a sterilization process, which can enhance the efficiency of heat transfer between a fluid transfer medium and product to be treated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is an isometric, side view of a stack of retort trays or baskets forming a crate;  
         [0012]      FIG. 2  is an upper isometric, end, side and bottom view of a retort tray used to form the crate of  FIG. 1 ;  
         [0013]      FIG. 3  is a close-up, side, isometric view of the retort tray of  FIG. 2 ;  
         [0014]      FIG. 4  is a front view of an embodiment of a retort with the cube of  FIG. 1  located therein;  
         [0015]      FIG. 5  illustrates another embodiment of a crate; and  
         [0016]      FIG. 6  illustrates another embodiment of a retort. 
     
    
     DETAILED DESCRIPTION  
       [0017]     The exemplary embodiments described herein provide an array of fluid distribution tubes or plenums which have a hollow core running through their length, as well as apertures or nozzles situated along their length, for dispersing the heat transfer fluid, for example, water or steam, evenly throughout the batch.  
         [0018]     Referring to the  FIG. 1 , a stack  10  of trays  12  (also referred to as racks or baskets) form a cube  14  (also referred to as a crate) having a top  15 , a bottom  17  and sides  19 ,  21 ,  23 ,  25 . As can be seen, the trays  12  are stacked, one on top of the other to form the cube  14 . The trays  12  include product receiving volumes  16  that are sized to receive product to be heated. The cube  14 , once formed, is sized to be placed within a crate receiving volume  18  of a retort  20  ( FIG. 4 ). In the illustrated embodiment, six trays  12  form the cube  14 . However, more or less trays  12  may be used depending on, for example, the size of the crate receiving volume  18  of the retort  20 .  
         [0019]     Referring now to  FIG. 2 , each tray  12  is separable from an adjacent tray and includes a top wall  22 , a bottom wall  24 , side walls  26  and  28  and open ends  30  and  32 . An array of openings  34  are formed in the top, bottom and side walls  22 ,  24 ,  26  and  28 , respectively, and distributed about the periphery of the tray  12 . The openings  34  facilitate steam or hot water distribution through the assembled crate  14 .  
         [0020]      FIG. 3  shows an enlarged view of the tray  12 . The tray  12  includes tube segments  36  that, in some embodiments, are evenly spaced and longitudinally aligned to form an imaginary line  38  between each row  40 . Each line  38  of longitudinally aligned tube segments  36  is spaced apart from an adjacent line of tube segments to allow for receiving product in the tray  12 . The line  38  of longitudinally aligned tube segments  36  also segregates each row  40  of product from an adjacent row.  
         [0021]     Each tube segment  36  has a bottom end  42  with an opening  44  at the bottom wall  24  of each rack and a length  46  that extends between the top wall  22  and the bottom wall  24 . The tube segments  36  further include an extended portion  48  that extends beyond the top wall  22  having a top  50 , in some embodiments, including a tapered portion  52 . An array of nozzles  54  are distributed along the length  46  of the tube segment  36 . In some embodiments, the nozzles  54  are sized to eject steam or heated water at a desired rate. The nozzles  54  may be simple openings, or more complex structures.  
         [0022]     The extended portion  48  of the tube segment  36  is sized to slidingly engage, in fluid impermeable fashion, the bottom end  42  of the tube segment  36  of an adjacent tray  12  stacked thereon (see trays  12   a  and  12   b  of  FIG. 1 ). The stacked trays  12  form plural, vertically aligned and connected tube segments  36 , acting effectively as a unitary ductwork of assembled tubes  54  ( FIG. 1 ) for the distribution of fluid throughout the stack  10 . The tapered portions  52  can facilitate a connection between the extended portions  48  and bottom ends  42  of tube segments  36  of stacked trays  12 . In some embodiments, the extended portion  48  and/or bottom end  42  is provided with a gasket (not shown) to facilitate a fluid-tight seal.  
         [0023]     Alternatively, instead of comprising stacked tube segments, each tube  54  may be a unitary, unsegmented perforated tube having a length of about the height of the cube  14  and installed therein as a unit through passages situated through the trays  12 . In such a case, an end of each such tube could interface with a manifold or other fluid distribution system to receive the working fluid for the system.  
         [0024]     Any suitable method may be used to form the trays  12 . As one example, multiple plates of, for example, stainless steel may be stamped to form the openings  34  and welded together to form its sides. The tube segments  36  may also be formed of stainless steel and by extruding tubular forms and welding them within the trays as shown.  
         [0025]     The above-described system may be used with the basket or cube loading system of U.S. Pat. No. 6,739,108, the contents of which are incorporated herein by reference, wherein trays are stacked layer by layer into a basket frame.  
         [0026]     Referring now to  FIG. 4 , the crate  14  of stacked trays  12  is shown within the retort  20 . The retort  20  includes a fluid delivery line or lines  56  that are used to deliver pressurized fluid from a source  58 . Delivery nozzles or connection sockets  60  are in communication with the delivery line  56  and, when the trays are loaded into the retort for a processing operation, are connected to openings in the top  50  of the uppermost tube segments  36  (see also  FIG. 1  where the nozzles/sockets  60  and line  56  are represented by arrows). In one example, the trays  12  are loaded into the retort  20 , aligned and moved upward such that the nozzles/sockets  60  engage the upper ends of the tube segments  36 .  
         [0027]     In some embodiments, the basket or cube  14  can be modified to provide a manifold along its upper portion to engage the tapered top  50  of the tube segments  36  emanating from the uppermost rack  12  of the cube, the manifold further having a connection such as a socket connection, with a fluid distribution system within the retort once loaded therein, so as to provide fluid distribution through the tube segments. Further, the bottom end  42  of the tube segments  36  may be blocked or closed at the bottom of the basket frame, to distribute the fluid uniformly along the length of the assembled tubes  54 . The heating medium is therefore allowed to flow directly to the internal and other areas of the crate alleviating the problem of uneven heating.  
         [0028]     In the exemplary embodiment illustrated by  FIG. 4 , the retort  20  includes a vibrating system  62  including an actuator  64  that includes a movable portion that extends into vessel  66  and is connected to a frame  66  by a linkage  68 . The actuator  64  is used to apply an impulse to the frame  66  to induce motion of the frame, cube  14  and product containers relative to the vessel  67 . In this embodiment, the delivery line  56  may be formed of a flexible tube to allow for movement of the cube  14 .  
         [0029]     Referring to  FIG. 5 , an alternative embodiment  70  is designed to accommodate a basket without trays, such as where product is dumped in a container. In this system, the tubes  54  are permanently fixed to a bottom  72  of the basket  74 . The bottom  72 , which is raised up and down in the basket, contains cut outs for each tube  54 , so that it can be raised from its resting position in the bottom of the basket, to a flush position at the top of the basket. The product can be distributed around the tubes  54  as required.  
         [0030]     Referring to  FIG. 6 , a retort system  76 , which, in many respects, may be similar to the retort system  20  of  FIG. 4  is an immersion-type retort system. The retort system  76  also includes a system  80  for introducing vibrations to a fluid within a pressure vessel  78  that contains the product. The vibrations may be provided using transducers  82  located within the vessel  78 . In some embodiments, the transducers  82  are located outside the crate receiving volume  18 . In other embodiments, the transducers  82  may be located within the crate receiving volume  18 . For example, the transducers may be carried by the trays  12 . A controller  84  may control activation of the transducers  82 .  
         [0031]     The fluid (e.g., water) serves as a fluid transfer medium for the wave energy. In some embodiments, sonic energy (i.e., less than about 20,000 Hz) may be provided. In other embodiments, ultrasonic energy (i.e., above about 20,000 Hz) may be provided. Providing the sonic or ultrasonic energy can reduce processing time comparted to systems without the system  80 .  
         [0032]     The embodiments herein described are done so in detail for exemplary purposes only, and may be subject to many different variations in design, structure, application and operation methodology. Thus, the detailed disclosures therein should be interpreted in an illustrative, exemplary manner, and not in a limited sense.