Abstract:
An impingement apparatus for use with a freezer includes a flexible belt having a first surface, a second surface opposite to the first surface, and a plurality of impingement holes extending through the belt between the first and second surfaces, wherein a passageway is formed in each one of the plurality of impingement holes and through which a cooling medium can pass.

Description:
BACKGROUND 
       [0001]    The present embodiments relate to apparatus and methods to chill or freeze products, such as for example warm food products or food products emitting steam vapor. 
         [0002]    Heated products having “steamy” characteristics due to their moisture content are a challenge to freeze. This is due to the moisture content in the water evaporating off the product to cause same to “plate out” or stick to cold, inner surfaces of the freezing apparatus or system for the product. Generally, moisture vapor from the product will freeze on surfaces inside the freezer. In a cryogenic tunnel freezer for example, the moisture will collect on fan blades used to circulate the cryogenic gas and thereafter compromise the blades effectiveness and eventually render the blades useless. In mechanical freezers, the moisture that is frozen usually ends up on the evaporator coils inside the freezer, resulting in blockage and ineffective use of the coils. 
         [0003]    Cryogenic immersion freezers have been used to overcome the deficiencies of cryogenic tunnel and mechanical freezers with respect to “steamy” products, such as food products. This is because cryogenic immersion freezers do not require moving parts for circulation of the freezing gas flow or evaporator coils. In a cryogenic immersion freezer, the food product is immersed in a bath of liquid nitrogen for freezing. However, cryogenic immersion freezers are extremely inefficient and not cost-effective when operating as stand-alone freezers for steamy food products. 
         [0004]    In addition, holes in an impingement plate used in a cryogenic tunnel freezer can clog or be sealed from the snow created by the steamy product condensation vapor. Accordingly, such freezers will need vibrators to mechanically clear the impingement holes of the frozen condensate. 
         [0005]    A freezer is therefore needed for steamy products, such as food products, which does not have the disadvantages of known cryogenic tunnel and mechanical freezers, or cryogenic immersion freezers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    For a more complete understanding of the present embodiments, reference may be had to the following description taken in conjunction with the drawing Figures, of which: 
           [0007]      FIG. 1  shows a side view in cross-section of an inpingement freezer embodiment for freezing hot products; and 
           [0008]      FIG. 2  shows a view taken along line  2 - 2  in  FIG. 1 . 
       
    
    
       [0009]    Before explaining the present embodiments in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0010]    The embodiments of  FIGS. 1 and 2  use a flexible moving conveyor belt having for example a metallic frame and a plastic (ultra high molecular weight (UHMW) or similar material) support members with a plurality of holes therethrough to maximize heat transfer coefficient of the freezing process and to accordingly be continuously cleared of any frozen concentrate. The plastic conveyor belt of the present embodiments is operable in atmospheres having cryogenic temperatures and is of a hygienic structure. 
         [0011]    Referring to  FIGS. 1 and 2 , the embodiments include an impingement belt apparatus shown generally at  10  and operatively associated with a freezer  12 . The freezer  12  is used to substantially reduce the temperature, such as to chill or freeze, products such as food products  14  which are introduced into the freezer in a warm or perhaps steam emitting phase from just being cooked or otherwise heated. The apparatus  10  can be retrofitted to existing freezers. 
         [0012]    The freezer  12  includes a housing  16  consisting of opposed side walls  18 , 20 , a top  22  or roof, a bottom  24 , a front wall  26  and a back wall  28 . A chamber  30  or internal space is disposed within the housing  16 , and it is within the chamber that the chilling or freezing of the food products  14  occurs. 
         [0013]    The front wall  26  is provided with an inlet  32  to the chamber  30 , while the back wall  28  is provided with an outlet  34  from the chamber. The inlet  32  and the outlet  34  are sized and shaped to permit a conveyor belt  36  having an upper run  38  and a lower run  40  to pass through the chamber  30  via the inlet and the outlet  34 , as shown in particular in  FIG. 1 . 
         [0014]    Referring to  FIG. 1 , two pairs of blowers are shown for example disposed for operation in the chamber  30 . That is, an upper pair of blowers  42 ,  44  or fans are mounted to the top  22  of the housing  16 . Each of the blowers  42 , 44  includes a motor  46 , 48 , respectively, which is attached via a shaft  50 , 52  to a blower wheel  54 , 56  of the corresponding blower. While the motors  46 , 48  are mounted external to the housing  16 , the shafts  50 , 52  and blower wheels  54 , 56  are disposed in the chamber  30 . Each one of the upper blowers  42 , 44  is provided with a corresponding louvered housing  58 , 60 , respectively. The louvered housings  58 , 60  are disposed in the chamber  30  mounted to an inner surface of the top  22  of the housing  16 . The remaining side walls of the louvered housings  58 , 60  can be selectively opened or closed, as shown in  FIGS. 1 and 2 , to control and vary a flow rate of the chilling atmosphere in the chamber  30 . For example, as shown in  FIGS. 1 and 2 , louvers  62 , 64  of the corresponding louvered housings  58 , 60  are all in an open position for maximum circulatory air flow within the chamber  30 . 
         [0015]    Referring still to  FIG. 1 , a lower pair of blowers  66 , 68  or fans are shown disposed for operation in the chamber  30 . That is, the lower pair of blowers  66 ,  68  are mounted to the bottom  24  of the housing  16 . Each of the blowers  66 , 68  includes a motor  70 , 72 , respectively, which is attached via a shaft  74 , 76  to a blower wheel  78 , 80  of the corresponding blower. While the motors  70 , 72  are mounted external to the housing  16 , the shafts  74 , 76  and the blower wheels  78 , 80  are disposed in the chamber  30 . Due to the perspective of  FIGS. 1 and 2 , the motor  70  is obscured from view and is therefore presented with a broken line in  FIG. 1 . Each of the lower blowers  66 , 68  is provided with a corresponding louvered housing  82 , 84 , respectively. The louvered housings  82 , 84  are disposed in the chamber  30  mounted to an inner surface of the bottom  24  of the housing  16 . The remaining side walls of the louvered housings  82 , 84  can be selectively opened or closed, as shown in  FIGS. 1 and 2 , to control and vary a flow rate of the chilling atmosphere in the chamber  30 . For example, as shown in  FIGS. 1 and 2 , louvers  86 , 88  of the corresponding louvered housings  82 , 84  are all in an open position for maximum circulatory air flow within the chamber  30 . 
         [0016]    As shown in  FIGS. 1 and 2 , one or a plurality of the impingement belt apparatus  10  may be used with the freezer. Referring in particular to  FIG. 1 , the impingement belt apparatus  10  includes a continuous flexible belt  100  having a plurality of holes  102  or apertures formed therein. The holes  102  permit air flow circulated through the chamber  30  to pass through the belt  100  as shown by the arrows  104 . The belt  100  is mounted for movement about a plurality of rollers  106  or pulleys. 
         [0017]    The apparatus  10  also includes a belt cleaner  108  mounted in the chamber  30  to be operationally associated with the belt  100 . The belt cleaner includes a plurality of projections  110 , such as posts or fingers, sized and shaped so that they can be received in the holes  102 . The belt cleaner  108  can be constructed as a drum  112  rotatable about its central axis at an axial  114 . The drum  112  is rotatable by any number of known motors or mechanical applications such that the rotation of the drum  112  brings the projections  110  into registration with the holes  102  to force out or extrude any frozen condensate in the holes from the belt. 
         [0018]    As shown in  FIG. 1 , the drum  112  of the apparatus  10  is disposed at a downstream end or near the outlet  34  of the housing  16 . This position may be more beneficial during freezing operations because introduction of the food product  14 , which is in a heated or steam emitting phase, into the chamber  30  through the inlet  32  will provide the greatest amount of steam vapor resulting in condensate when subjected to the cryogen atmosphere being circulated within the chamber. Therefore, as the conveyor belt  36  is moved through the chamber  30  and as the impingement belt  100  is also moved through the chamber, condensate will begin to rapidly form in the holes  102  of the belt  100  such that there is an increased chance that a greater number of the holes  102  will be substantially clogged or caked with frozen condensate by the time the belt  100  approaches the outlet  34 . Therefore, it is at this position as shown in  FIG. 1  that the projections  110  of the drum  112  will be most effective because they will remove the greatest amount of condensate in the holes  102  prior to the belt  100  returning along its continuous path back to a position proximate the inlet  32 . 
         [0019]    As also shown in  FIGS. 1 and 2 , another impingement belt apparatus shown generally at  210  can be mounted for operation at a lower portion of the chamber  30  within the housing  16 . Elements illustrated in  FIGS. 1 and 2  corresponding to the impingement belt apparatus  10  have been designated by corresponding reference numerals increase by 200, and such elements are designed for use in the same manner as the elements of the apparatus  10 . 
         [0020]    As shown in  FIG. 2 , the upper blowers  42 , 44  and the lower blowers  66 , 68  are offset in the chamber  30  from the impingement belt apparatus  10 , 210 . The louvers  62 , 64  and  86 , 88  for each of the respective housings  58 , 60  and  82 , 84  can be selectively positioned in any combination of open and closed positions in order to adjust the air flow and circulatory effect of the chilling atmosphere within the chamber  30 . A cryogen gas, such as nitrogen, can be introduced into the chamber  30  with any known and acceptable apparatus or systems (not shown). 
         [0021]    The holes  102 ,  202  may be of different diameters and arranged in different patterns in the impingement belt  100 , 200  depending upon the food product to be chilled or frozen and the amount of time necessary to provide the heat transfer coefficient. An increased heat transfer rate is provided by the impingement belt apparatus  10 , 210 . 
         [0022]    The upper blowers  42 , 44  and the lower blowers  66 , 68  can also cycle from an operating (chilling/freezing) mode to a defrost mode. That is, when necessary, one of the upper blowers  42 , 44  and/or the lower blowers  66 , 68  will cycle off and have the respective louvers  62 , for example, closed so that same can be defrosted. The other one of the blowers will remain in operation and continue circulating the atmosphere within the chamber  30 . The defrost cycle for the corresponding blower to be defrosted can occur with a warm gas, which can be exhaust gas if necessary to maximize efficiency of the freezer  12 . The defrost cycle can continue concurrent with and throughout the operating cycle of the remaining blowers. Accordingly, that is why the blowers  66 , 68  are disposed at the bottom  24  of the housing  16  which will facilitate drainage if defrosting is to occur. 
         [0023]    With respect to the embodiments shown at  FIGS. 1 and 2  and the louvered housings  58 , 60  and  82 , 84 , for such housings, at least two sides of each one of the respective housings must be louvered, preferably opposed sides of the housing, to provide the necessary intake and exhaust for the circulatory flow of the chilling atmosphere in the chamber  30 . The remaining sides which do not have louvers, such as for example  62 , 64 , can be of solid construction. 
         [0024]    The impingement belt  100 , 200  can be arranged around the respective roller  106 , 206  as a continuous loop or belt, and can be manufactured from stainless steel, low temperature resistant plastic or low temperature resistant polymer. The projection member  109 , 209  can extend for example from 4 mm to 30 mm from a surface of the drum  112 , 212 , and similarly for example be manufactured from stainless steel, low temperature resistant plastic or low temperature resistant polymer 
         [0025]    It will be understood that the embodiments described herein are merely exemplary, and that one skilled in the art may make variations and modifications without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention as described and claimed herein. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments of the invention may be combined to provide the desired result.