Abstract:
A high throughput, short batch cycle commercial ice making machine produces commercial ice which resists melting in convenient sizes for mobile food carts, market produce, or fish displays. The machine introduces super-cooled water, that is in a liquid state while exposed to a temperature below freezing, into a batch of pre-formed hollow molds of one or more horizontally oriented ice forming freezing trays oriented horizontally. Using vapor compression refrigeration, the machine produces a plurality of supercooled ice segments in pockets within the freezing tray. The supercooled ice segments are rapidly subjected to a short, temporary contact with a high heat source from a sleeve integral with the freezing tray compartments, along a peripheral bottom surface of the ice segment accommodating freezing tray molds. This temporarily melts a bottom surface of each ice segment, lubricating it and loosening it. Then the machine rotates the freezing tray containing the batch of ice segments about its horizontally oriented axis to a vertically oriented dump position, thereby dumping the temporarily heated ice segments into the freezing tray.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to making ice cubes in a horizontally oriented freezing tray having refrigerant and evaporator conduits integral with, and in intimate contact with, the ice cube mold compartments of a freezing tray, so that the resultant ice cubes have a long shelf life before melting.  
         BACKGROUND OF THE INVENTION  
         [0002]    Commercial ice in convenient sizes for mobile food carts, market produce, or fish displays is needed in large quantities. However, especially in warm weather, the ice melts quickly and must be replenished several times per day.  
           [0003]    Many ice making machines make ice in vertically oriented freezing trays. In vertical dripping, the later dripped water freezes differently than the earlier dripped water in a vertical cascade. In addition, freezing is inhibited because the vertical inflow of water releases more energy as the water cascades down, thus slowing the freezing time due to the activity of the flowing, cascading water.  
           [0004]    Among relevant vertically oriented ice making patents include U.S. Pat. No. 4,474,023 of Mullins for an ice making machine. In Mullins &#39;023, ice is formed by dripping water in vertically disposed trays, freezing the water into cubes, loosening the cubes by applying heat through adjacent evaporator conduits, then rotating the trays approximately 30 degrees downward from a vertical position, thereby dumping the formed ice cubes into a bin. Flexible hoses are used in Mullins &#39;023 for transporting both the water and the refrigerant in order to allow pivoting of the freezing tray from the vertical water loading position to the partially face-down dumping position. Mullins &#39;023 uses a high heat source in a cycle reversal for causing temporary loosening of the cubes from their individual molds within the tray, but the evaporator is attached to the tray, not integrally formed therewith. As a result, the tray contacting surface of the ice cubes is not uniformly and quickly heated for a quick melt and release therefrom.  
           [0005]    A similar ice cube making machine with a vertically oriented freezing tray is described in U.S. Pat. No. 4,459,824 of Krueger. However, the vertical orientation of Mullins &#39;023 and Krueger &#39;824 increases drip inflow time, which provides a barrier to super-cooling of the water for forming the ice.  
           [0006]    U.S. Pat. No. 4,255,941 of Bouloy describes an ice making machine which is vertically oriented. In Bouloy &#39;941, there are shown two freezing trays  22  welded back-to-back, wherein the trays  22  with semi-circular molds  32  for each ice cube have spaces  48  between the trays  22  for a reverse flow of alternately flowing refrigerant and evaporator gas. The hot gas is used to melt the ice cubes  124  from their molds  32  in each of the two back-to-back freezing trays  22 .  
           [0007]    The spaces  48  of Bouloy &#39;941 are arcuate triangles formed between the rounded backs of the semi-circular molds  32  forming the ice cubes  
           [0008]    The disadvantage of Bouloy &#39;941 is that since the two molds are welded back-to-back, at the weld seams between the two molds each labeled  22 , the refrigerant and alternately the hot gas can&#39;t flow through these closed seams, so there is not uniform intimate contact of the hot gas with the bottom of each ice cube mold  32  of each of the freezing trays  22 .  
           [0009]    U.S. Pat. No. 4,199,956 of Lunde describes an ice cube making machine which requires an electronic sensor to interrupt the freezing cycle to thaw the cubes for dumping.  
           [0010]    U.S. Pat. No. 6,233,964 of Ethington describes an ice cube making machine with a freezing cycle and a hot gas defrost valve used with a detector for detecting frozen ice. Ethington &#39;964 is similar to conventional ice making machines in hotels and other commercial establishments.  
           [0011]    Among other US Patents for loosening frozen ice cubes from a tray ice include U.S. Pat. No. 3,220,214 of Cornelius for a spray type ice cube maker.  
           [0012]    Moreover, among patents which heat trays for loosening ice cubes include U.S. Pat. No. 5,582,754 of Smith, which uses electrical heating elements to thaw semi-circular ice cubes from a freezing tray. In addition, U.S. Pat. Nos. 1,852,064 of Rosenberg, 3,318,105 of Burroughs, 2,112,263 of Bohannon 2,069,567 of White and 1,977,608 of Blystone also use electrical heating elements to thaw cubic ice cubes from a freezing tray. In Bohannon &#39;263, Burroughs &#39;105 and White &#39;567, the electrical heating elements are arrayed in longitudinally extending heating elements which extend adjacent to the sides and bottoms of ice cube freezing tray ice cube forming compartments, but the heating elements do not provide uniform heat all along an under-surface of each ice cube tray compartment.  
           [0013]    U.S. Pat. No. 2,941,377 of Nelson uses serpentine conduits of evaporation fluid for loosening ice cubes, but only along the sides of the ice cube tray molds  
           [0014]    U.S. Pat. Nos. 1,781,541 of Einstein, 5,218,830 of Martineau and 5,666,819 of Rockenfeller and 4,055,053 of Elfving describe refrigeration units or ice making machines which utilize heat pumps for alternate heat and cooling.  
           [0015]    Therefore, the prior art patents have the disadvantage of not allowing for supercooling of water on a horizontally oriented tray, and not allowing for rapid but effective heating of all of the undersurface of each ice cube from adjacent evaporator conduits conforming to the surface of the ice cube forming tray compartment molds, to provide only a slight melting of the undersurface of each ice cube for lubricating each cube prior to dumping in a supercooled state into a collection harvesting bin.  
           [0016]    Furthermore, among the vertically oriented ice making machines such as of Mullins &#39;023 or Bouloy &#39;941, there is no way to use the freezing trays horizontally as a display counter, such as in a fish market or retail store.  
         OBJECTS OF THE INVENTION  
         [0017]    It is therefore an object of the present invention to provide super-cooled ice cubes with a long shelf life before melting, and to improve over the disadvantages of the prior art.  
           [0018]    It is yet another object of this invention to maximize the use of a horizontally oriented freezing tray of an ice making machine, wherein the horizontally oriented freezing tray has integral hollow sleeves in intimate contact with the freezing tray, to facilitate the rapid freezing and discharge of the ice from the freezing tray.  
           [0019]    Other objects which become apparent from the following description of the present invention.  
         SUMMARY OF THE INVENTION  
         [0020]    In keeping with these objects and others which may become apparent, the present invention is an efficient method of producing this commodity of melt-resistant ice is described by this invention. The method and apparatus of this invention uses one or more horizontally oriented freezing trays in combination with conventional vapor compression refrigeration using common refrigerants such as, for example, “Free Environmental Refrigerant number 404A”. The quality of the product is superior as the apparatus outputs ice segments that are supercooled (below or near 0 degrees F.) well below freezing temperature thus affording even more cooling capacity per pound than just the heat absorbed by the solid to liquid transition. The ice is produced in batches in horizontally oriented freezing trays, wherein the batches are then dumped automatically from the freezing trays.  
           [0021]    Because the freezing trays are horizontally oriented, the water is dripped at a uniform rate, unlike cascading water flowing down vertically oriented freezing trays. These horizontally oriented freezing trays can also be used as counters for displaying objects kept at cold temperatures, such as fish at a fish market or retail store. Moreover, these horizontally oriented freezing trays can be stacked horizontally one on top of each other for maximum use.  
           [0022]    The rapid cycle time achieved insures very good capital efficiency as the weight of ice produced per day is high with respect to the cost of the apparatus.  
           [0023]    Key elements of this invention that contribute to its superior performance include the design of the freezing trays which form an integral evaporator, as well as the method of dumping the ice product by rotating the tray from the horizontal to a vertical position. This rotation is facilitated by the use of flexible coolant hose connections to the freezing trays.  
           [0024]    By cycle reversal (similar to a heat pump cycle), hot refrigerant is directed into the evaporation spaces in the trays for a brief “thaw” cycle which creates a thin layer of water at the interface between the ice segment and the tray surface thereby dislodging the ice segment while the tray is in the vertical position with the water layer acting as a “lubricant” to further aid in the dumping process. Since the “thaw” cycle has very high heating power causing a high temperature difference between the heated tray surface and the ice segment, this cycle is short, and the heating of the ice surface is therefore localized to a thin liquid interface layer which quickly refreezes upon being dumped due to heat transfer to the interior of the supercooled ice segment.  
           [0025]    Therefore, to summarize the key features, integral evaporation channels within the horizontally oriented freezing trays contribute to short freezing cycles; rotation of freezing trays is facilitated by coolant hose connections; dumping of ice product is accomplished by refrigeration cycle reversal heating freezing trays internally; product produced is convenient sized ice segments that are supercooled. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]    The present invention can best be understood in connection with the accompanying drawings. It is noted that the invention is not limited to the precise embodiments shown in drawings, in which:  
         [0027]    [0027]FIG. 1 is a Side elevation view of an ice making system of this invention;  
         [0028]    [0028]FIG. 2 is a Perspective view of an ice tray of this invention;  
         [0029]    [0029]FIG. 3 is a Crossection view of an ice tray channel;  
         [0030]    [0030]FIG. 4 is a Perspective view of an ice segment as produced by the apparatus of this invention;  
         [0031]    [0031]FIG. 5 is an End view of freezing tray in the fill/freezing position;  
         [0032]    [0032]FIG. 6 is an End view of freezing tray in the ice cube dump position;  
         [0033]    [0033]FIG. 7 is a Plumbing schematic of this invention showing fluid paths for both freezing and “thaw” cycles;  
         [0034]    [0034]FIG. 8 is an Electrical block diagram of this invention;  
         [0035]    [0035]FIG. 9 is a Timing diagram of ice making cycle of this invention;  
         [0036]    [0036]FIG. 10 is a Side elevation view of an alternate embodiment for an ice making system having a countertop display and a removable water inlet source, shown in the water introduction phase;  
         [0037]    [0037]FIG. 11 is a Side elevation view of the alternate embodiment as in FIG. 10 for an ice making system having a countertop display, with the water inlet source shown removed upward away from the countertop display;  
         [0038]    [0038]FIG. 12 is a Perspective view of the countertop freezing tray portion of the embodiment of FIGS. 10 and 11, shown with fish displayed thereon; and,  
         [0039]    [0039]FIG. 13 is a Perspective view of an alternate embodiment for an ice tray functioning as a physical therapy bed, shown with a user lying thereon. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0040]    [0040]FIG. 1 presents an illustration of an embodiment of this invention as a complete ice making system  1  housed on an upper floor  2  and a lower floor  3  of a building. The ice making apparatus  5  rests on support floor  4  which has a large opening communicating with the floor  3  below. Under this opening is conveyor belt  25  which moves dumped ice segments  26  to bin  27  which rests on the lower floor surface  28 . A vapor compression refrigeration system  11  (part of ice making apparatus  5 ) includes compressor motor  12 , compressor  13 , fan motor  16 , fan  15 , heat exchanger  14 , and rigid refrigerant lines  17 .  
         [0041]    Frame  6  supports a horizontally oriented lower ice tray  21  with rotator housing  23  and a horizontally oriented upper ice tray  20  with its rotator housing  22 . Control housing  10  is also attached to frame  6 .  
         [0042]    Flexible refrigerant hoses  18  connect upper tray  20  to housing  10 , while corresponding hoses  19  connect to lower ice tray  21 . Fixed housings for the two looped hose bundles  18  and  19  have been removed for this illustration.  
         [0043]    Prechilled water at just above the freezing point enters at  9  and is distributed by manifold and drip tubes  7  to upper horizontal tray  20  while manifold and drip tubes  8  serve the same function for lower horizontal tray  21 . While dual horizontal ice trays are shown in this embodiment, an ice making machine with only one horizontal freezing tray or with as many as three stacked horizontal freezing trays may be configured to serve the desired capacity. A single ice tray system will be described in the following detailed discussion. Implementation on two separate floors of a building as illustrated is also not required; a conveyor can be placed within frame  6  on a single floor of a building. The prechilled water from which ice is made can be supplied by a separate chiller or by a heat exchanger on the evaporator line.  
         [0044]    [0044]FIG. 2 shows horizontally oriented ice tray  20  which includes one or more attached troughs  36 , such as four, with ice segment separators  35 .  
         [0045]    [0045]FIG. 3 is a crossection of a trough  36  showing inner ice forming surface  38  which is circular attached at edges  41  to outer layer  39  which is also circular, but of a smaller radius. This construction creates an enclosed space  40  through which refrigerant is conducted. The material for the trough can be copper which is brazed at edges  41  and then nickel plated. Other materials of high heat conductivity can be used as well. Welded stainless steel construction can be used for making brine ice for low temperature applications.  
         [0046]    It is understood that water resting on surface  38  would freeze if liquid refrigerant is permitted to evaporate within space  40 ; similarly, hot refrigerant vapors in space  40  would tend to condense melting ice in contact with surface  38 . Ice segment separators  35  are similarly attached as by brazing or welding; they are made of the same material as the two layers of the trough.  
         [0047]    [0047]FIG. 4 shows ice segment  26  with width W, length L and depth D. The maximum depth, Dmax, would be W/2 thereby making the end contour into a semicircle. It has been found that a more shallow configuration dumps easier (shorter cycle time). Length L can be much longer than W if desired for some applications; this is regulated by the placement of spacers  35 .  
         [0048]    [0048]FIGS. 5 and 6 show two positions of ice tray  20 . In FIG. 5, it is in a slightly tilted position from horizontal (angle “h”) to facilitate filling from drip tubes  7  with any overflow of chilled water captured and returned in trough  47 . After the filling period, the water in horizontal tray  20  is frozen while in this position.  
         [0049]    Typically,  3  hoses are attached to each horizontal tray  20 , two smaller evaporator hoses (approximately ⅜″ diameter) and a suction hose (about ½″ diameter). These types of hoses are currently used to carry refrigerant in truck mounted units. In this figure only the vapor hose  45  is shown so as to more clearly illustrate the spiral shape of the flexible connection from tray hose plate  46  to fixed attachment end at “F”. Housing  48  would occupy the outline as shown.  
         [0050]    After the ice is formed, horizontally oriented tray  20  is rotated clockwise (A) into the vertical position shown in FIG. 6. Note that the spiral of hose  45  is now tighter. When “thaw” heating is applied while in this position, ice segments  26  are dumped from tray  20 . After the dumping cycle is complete, tray  20  is rotated counterclockwise (B) back to the horizontal position for the next ice making cycle.  
         [0051]    Both the ice making (freezing) cycle as well as the thaw cycle flow are shown on the flow schematic of FIG. 7. In addition to components already mentioned, expansion/throttle valve  57  with bypass check valve  58 , expansion/throttle valve  59  with bypass check valve  60 , as well as 3-port solenoid valves  55  and  56  are shown.  
         [0052]    In the freeze cycle (shown by solid arrow shafts), liquid refrigerant flows through expansion valve  59  into ice tray  20  where it evaporates by extracting heat from ice water thereby freezing it. Suction is drawn from horizontal tray  20  by a path from orifice “C” to orifice “A” of solenoid  56  to the input of compressor  13 . Refrigerant vapors are compressed and emerge from compressor  13  as hot vapors through orifice “A” to orifice “B” of solenoid  55  and onward to heat exchanger  14  which is now acting as a condenser with liquid refrigerant flowing through check valve  58  to complete the cycle.  
         [0053]    For the thaw cycle (shown by dashed arrow shafts), liquid refrigerant flows through expansion valve  57  into heat exchanger  14  which now acts as an evaporator extracting heat from environmental air to vaporize refrigerant. Suction is drawn from heat exchanger  14  by a path from orifice “B” to orifice “A” of solenoid  56  to the input of compressor  13 . Compressed hot vapors emerge from compressor  13  through orifice “A” to orifice “C” of solenoid  55  and onward to ice tray  20  which now acts as a condenser giving up heat to melt a surface of ice segments whereby refrigerant is condensed to a liquid which flows through check valve  60  to complete the cycle. Note that segments of piping  61  and  62  denote flexible hoses.  
         [0054]    Certain controls and electrical wiring are required to support the activity described in FIG. 7.  
         [0055]    For example, FIG. 8 is an electrical block diagram which describes the functioning of this invention. Either three phase AC or single phase 3-wire utility electricity enters at  70 . Utility box  71  contains protection fuses. Contactor  72  applies power the entire ice making system including refrigeration subsystem  11 . A master timer  73  controls the timing of the various components; solenoid  74  which controls the filling of ice tray  20  is directly controlled. Motor controller  75  gets its timing cue from master timer  73  to initiate the operation of motor  76  which changes the position of tray  20  form one position to the alternate position. Limit switch  78  stops motor  76  when tray  20  has reached the fill position; limit switch  77  stops motor  76  when tray  20  has reached the vertical position. Solenoid controllers  79  and  80  control solenoids  55  and  56  respectively upon cues from master timer  73 . While illustrated as an open-loop control, timer  73  can be enhanced with feedback sensors such as temperature and/or refrigerant pressure sensors; however, since operating conditions should be quite invariant once initially set up, this refinement may not significantly improve efficiency and can contribute to unreliable operation.  
         [0056]    [0056]FIG. 9 shows a timing diagram of the various operations. The timing relationships, durations, and overlap can be seen for a typical installation. A total cycle time for making an ice batch of ten minutes is achievable with proper matching of the various parameters. This would be illustrated by the chart distance from the start of a “water fill” pulse to the next. Water filling, freeze periods, dump turning, thaw periods, and fill turning are illustrated in the timing diagram.  
         [0057]    [0057]FIGS. 10, 11,  12  and  13  show alternate embodiments with respect to the horizontal orientation of the freezing tray.  
         [0058]    In FIGS. 10 and 11, inlet drip tubes  108  are shown close to freezing tray  121  for introducing water, and then inlet drip tubes  108  lifted out of the way as in FIG. 11, so that tray  121  can be used as a counter-top for displaying fish for sale at a fish store, as shown in FIG. 12.  
         [0059]    FIGS.  10 - 12  presents an illustration of an embodiment of this invention as a countertop display ice making system  101 . The ice making apparatus  105  rests on support floor  104  which has an optional drain opening  124  communicating with the floor  104 . A vapor compression refrigeration system  111  (part of ice making apparatus  105 ) includes compressor motor  112 , compressor  113 , fan motor  116 , fan  115 , heat exchanger  114 , and rigid refrigerant lines  117 .  
         [0060]    Frame  106  supports a liftable or removable horizontally oriented ice tray  21  with lift mechanism  123 . Control housing  110  is also attached to frame  106 .  
         [0061]    Flexible refrigerant hoses  119  connect horizontal countertop tray  121  to housing  110 .  
         [0062]    Prechilled water at just above the freezing point enters at inlet  109  and is distributed by manifold and drip tubes  108  to horizontal countertop freezing tray  121 . While liftable horizontal countertop ice tray  121  is shown in this embodiment, an ice making machine with a removable or horizontally shiftable horizontal countertop freezing tray or trays  121  may be configured to serve the desired capacity. The prechilled water from which ice is made can be supplied by a separate chiller or by a heat exchanger on the evaporator line.  
         [0063]    [0063]FIG. 12 shows horizontally oriented countertop ice tray  121  displaying fish  180  thereon. Tray  121  includes one or more attached troughs  136 , such as four, with ice segment separators  135 .  
         [0064]    [0064]FIG. 13 shows an even further alternate embodiment where the horizontal freezing tray  220  is used as a physical therapy bed device for a human patient  280  with a need for ice application to the back, neck or limbs. FIG. 13 shows corresponding attached troughs  236  with ice segment separators  235 . It is anticipated for user comfort that the tops of troughs  236  and separators  235  are covered with an soft elastomeric material, such as rubber or synthetic materials such as polyurethane foam.  
         [0065]    Furthermore, in the embodiments of FIGS.  10 - 13  where the ice can remain in place and does not have to be dumped until melted after use as a display countertop or physical therapy bed, then the introduction of hot gas in the curved hollow sleeves under respective ice segment compartments  136  or  236  can be optional if the ice formed just stays in place until melted, such as in a fish display or in the physical therapy bed embodiment. In that case one would only need the refrigerant to flow through hollow arcuate sleeves similar to hollow arcuate sleeves  40  in FIGS.  1 - 3  herein, to freeze the water in horizontal countertop tray  121  of FIG. 12 or physical therapy bed  221  of FIG. 13.  
         [0066]    In the foregoing description, certain terms and visual depictions are used to illustrate the preferred embodiment. However, no unnecessary limitations are to be construed by the terms used or illustrations depicted, beyond what is shown in the prior art, since the terms and illustrations are exemplary only, and are not meant to limit the scope of the present invention.  
         [0067]    It is further known that other modifications may be made to the present invention, without departing the scope of the invention, as noted in the appended claims.