Abstract:
An ice maker for use in a refrigeration apparatus as well as a method of optimizing ice production in an ice maker. The ice maker has a mold and a fan selectively operable to direct moving cold air past the mold during the ice formation process. In the preferred embodiment, the fan does not operate during the harvest portion of the cycle. A fan assembly consisting of a fan or blower, a motor, a switch in series with the motor and leads for electrically interconnecting the motor and in switch with the icemaker power supply is preferably assembled as a module removably interconnectable with the icemaker as an optional feature. The icemaker has an increased the rate of ice production due to the increased rate of convective heat transfer.

Description:
BACKGROUND OF THE PRESENT INVENTION 
     The present invention relates to ice makers within enclosed freezer compartments of refrigeration appliances and more particularly to a method of enhancing the ice production of such ice makers. 
     The present invention is directed to improvements in the type of icemakers exemplified by those disclosed in U.S. Pat. Nos. 4,756,165 and 4,799,362, owned by the assignee of the present invention, wherein an ice mold and associated ice maker mechanism are mounted in the freezer compartment of a domestic combination refrigerator/freezer apparatus. The ice maker includes a mold in which water is frozen to form a plurality of ice bodies. An electric motor rotates the mold when the ice has formed. An electric heater in heat transfer association with the mold frees the ice bodies from the mold and the ice bodies are ejected from the mold. The ice maker includes a control circuit with a thermostat responsive to the temperature of water in the mold. A thermostat switch is controlled by the thermostat to initiate and terminate operation of the ice maker motor for ejecting the ice body upon complete freezing thereof and concurrently energizing the heater. 
     In domestic combination refrigerator/freezers, the rate at which a component ice maker located in the freezer compartment can make ice is limited by the fact that the evaporator fan cycles on and off with the compressor. During the “off-cycle”, which can be as much as 70% of the time depending on ambient conditions, the rate of heat removal from the ice maker mold is drastically reduced compared to the “on-cycle” due to the loss of the forced air convection. Since the air within the freezer is controlled to be significantly below freezing during the “off-cycle”, what is required to maintain the efficient and rapid rate of ice production that is available during the “on-cycle” is to provide a means to keep the air moving over the mold. Running the evaporator fan during this period may not be desirable, since it would normally draw air from the refrigeration compartment past the evaporator and into the freezer compartment, warming both. 
     In fact, it has been experimentally observed that the rate of ice production in domestic combination refrigerator freezers with these and similar ice makers is greatly affected by the ambient temperature of the room. More particularly, when the room is warmer, it has been observed that the compressor operates more frequently and that the ice making production rate increases. It has been experimentally determined by the present inventors that the rate of ice production is directly and drastically influenced by the amount of airflow across the ice forming components of the ice maker. 
     Therefore, what is needed to obtain a reliable optimal ice production rate is to provide for sufficient airflow across the ice maker during ice making regardless of the ambient temperature. 
     In U.S. Pat. No. 4,799,362 there is further disclosed an ice maker similar to the one described in U.S. Pat. No. 4,756,165 but modified to provide pre-selected circuit test probe points for cooperation with a test apparatus for testing the operating condition of components of the ice maker. The test probe points allow inspection during manufacture or maintenance of the operation of the icemaker. 
     It would be advantageous to use test probe points of this type for the dual purpose of monitoring the operation of the icemaker to determine when airflow should be increased to provide optical ice production. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention is directed to a method and apparatus for improved ice production within a freezer or within the freezer compartment of a combination refrigerator/freezer. The present invention improves the rate of ice production by providing a fan selectively operable to direct cooled air across the ice making surfaces of the ice maker during the ice formation process. 
     In one embodiment of the present invention, a fan or blower is disposed at the rear of the freezer compartment and is selectively operable to direct air from the freezer compartment forward towards and across the ice forming components of the ice maker apparatus. 
     In a second embodiment of the present invention, a fan or blower, is mounted to a forward portion of the ice making apparatus and is selectively operable to direct air rearwardly towards and across the ice forming components of the ice making apparatus. 
     In the second embodiment, the fan or blower is part of a fan assembly selectively and removably mountable to the ice maker assembly an optional feature. 
     In either embodiment, the fan assembly preferably takes power off of pre-selected power test connection points on the ice maker which supply power when the ice maker is in the ice forming portion of its cycle. 
     In either embodiment, the fan is preferably selectively operable to run only when the ice maker is powered to make ice and does not operate during ice harvest. 
     It is therefore an object of the present invention to provide an ice maker having an optimized rate of ice production regardless of ambient conditions. It is another object of the present invention to provide an upgrade module for an ice maker such that it may be provided in a conventional configuration or, by interconnecting the upgrade module, in an optional high ice production configuration. It is yet another object of the present invention to provide an ice maker having a means to increase air flow across the mold at times selected to produce optimized production ice where such times are determined by monitoring preselected ice maker control circuit test points indicative of such preselected times. 
     It is still another object of the present invention to provide a method of optimizing ice production in an ice maker in a refrigeration device by increasing air flow across the mold at preselected times independent of ambient room conditions. It is another object of the present invention to provide a method of optimizing ice production in an ice maker in a refrigeration device by increasing air flow across the mold at times selected to produce optimized production ice where such times are determined by monitoring preselected icemaker control circuit test points indicative of such preselected times. 
     These and the many objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of the present invention in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the appended drawings, wherein like reference numerals refer to like components throughout: 
     FIG. 1 is a front elevation view of a combination refrigerator freezer having a first embodiment of an ice maker assembly and an ice maker fan assembly according to the present invention in the freezer compartment thereof; 
     FIG. 2 is an enlarged front perspective view of the ice maker assembly of FIG. 1 and a portion of the freezer compartment; 
     FIG. 3 is a side elevational view of the icemaker assembly of FIGS. 1 and 2 showing certain features of the ice maker apparatus and the fan assembly thereof; 
     FIG. 3A is a partial side elevational view of the ice maker assembly of FIGS. 1 and 2, but with a conventional cover replacing the fan assembly thereof; 
     FIG. 4 is a rear elevation view of the fan assembly of FIG. 3; 
     FIG. 5 is an exploded view of the fan assembly of FIGS. 3 and 4; 
     FIG. 6 is a front elevational view of the ice maker assembly of FIG. 3 with the fan assembly removed; 
     FIG. 7 is a schematic wiring diagram illustrating the method and apparatus for controlling the fan assemblies of FIGS. 1 through 5; 
     FIG. 8 is an enlarged front perspective view of an ice maker assembly and a portion of a freezer compartment similar to FIG. 1 but illustrating a second embodiment of the fan assembly according to the present invention; and 
     FIG. 9 is a cutaway side view of the fan assembly of FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention relates to ice makers for freezers and combination refrigerator/freezer appliances and more particularly to a method of enhancing the ice production of such ice makers. In particular, the present invention provides an improved method and apparatus for the delivery of moving cool air to the ice making components of an ice maker such as to increase the rate of ice production by increasing the rate of connective heat transfer. 
     The detailed description and in the drawings forming a part of this patent specification, the present invention is described in connection with ice making apparatus of the time illustrated and described in U.S. Pat. No. 4,756,165 invented by Paul B. Chestnut and Ronald W. Guess (“Guess &#39;165”) and the test apparatus for an ice making apparatus illustrated and described in U.S. Pat. No. 4,799,362, invented by Paul B. Chestnut (“Chestnut &#39;362), the contents of which are hereby incorporated by reference into the present application. 
     While use of the present invention in connection with the ice making and test apparatus of Guess &#39;165 and Chestnut &#39;362, which constitutes the best mode contemplated by the inventors for carrying out the present invention at the time of filing the present application, it should be understood that the present invention is believed to be applicable generally to any ice making apparatus having an ice mold located in the freezer compartment of a refrigeration appliance and therefore the claims appended hereto are not intended to be limited to this configuration. 
     Referring now to the drawings and more particularly to FIG. 1, a refrigeration apparatus such as a refrigerator  10  has a cabinet  12  having a freezer compartment  14  defined by a back wall  16 , pair of sidewalls  18  and  20 , a top wall  22 , a bottom wall  24 . The freezer compartment is selectively enclosed in normal operation by a freezer door  26 . The refrigerator  10  further has a fresh food compartment, not visible in the drawing but well known in the art, which is similarly selectively enclosed during normal operation by a refrigerator door  28 . 
     In the example illustrated, the refrigerator  10  is a side by side combination refrigerator/freezer, but it the icemaker and method of the present invention could function equally effectively in a top mount refrigerator/freezer of the type illustrated in Chestnut &#39;362 or in a chest freezer or upright freezer, as are well known in the art. 
     The refrigerator  10  has a power supply, a cooling system, an air distribution system and a refrigerator control system, not illustrated but well known in the art. As shown schematically in FIG. 7, the refrigerator control system  112  obtains power from the power supply  114  and is adapted to control the operation of the cooling system and air redistribution system so as to maintain the refrigeration compartment and the freezer compartment  14  approximately at preselected respective temperature levels. 
     The freezer compartment  14  has a plurality of interior shelves  30  mounted to the side walls  18  and  20  as well as door shelves  32  for the storage of food items. 
     The freezer compartment further has an ice maker assembly  34  mounted to one of the sidewalls  18 . An ice bin  36  is slideably and removably mounted within the freezer compartment  14  below the ice maker assembly  34  on guides  36 ,  38  and  40  mounted to the sidewalls  16  and  18 . A garage door panel  42  is typically pivotally mounted to the sidewall  18  and the ice maker assembly  34 . The garage door panel  42  is pivotable between a raised and horizontal position illustrated in FIG. 2 and a lowered and vertical position illustrated in FIG. 1 enclosing the region  44  above the ice bin  36  which is not occupied by the ice maker assembly  34 . 
     Referring to FIGS. 2 and 3, the icemaker assembly  34  includes an ice making apparatus  50  having a plurality of molds  52  in which ice bodies are formed. As is well known in the art and therefore not shown in the drawing or described herein in detail, the ice maker assembly  34  includes water delivery system for periodically supplying water to the molds  52 , a heater for heating the molds  52  a motor for moving the mold, typically by rotation, from an ice forming orientation to an ice delivery orientation, a heater for heating the mold to facilitate the separation of the ice bodies, and ice ejection apparatus for ejecting the ice bodies from the mold and permitting them to fall into the ice bin  36 . Further, as is well known in the art and therefore not shown in the drawing, an ice maker control circuit controls the operation of the water delivery system, the motor, the heater, and the ejection apparatus to regulate the production of ice bodies and delivery of the ice bodies to the ice bin  36  when the ice maker assembly is operating. An exemplary ice making apparatus  50  is shown and described in structural and operational detail in Guess &#39;165. 
     A bin lever arm  54  is pivotally mounted to the housing of the ice maker assembly  34  such as to pivot between a lowered position disposed partially within the ice bin  36  and raised positions disposed significantly above the ice bin  34 . As is well known, the bin lever arm operates a switch, not shown, operable to cause the ice maker control circuit to halt the production of by the ice making apparatus  50  when the bin lever arm is pivoted above a preselected height relative to the ice bin  36  whereby, as ice bodies are added to the ice bin, the bin lever arm is raised by the ice bodies until the bin lever arm reaches the preselected height whereupon ice production ceases. 
     Referring to FIGS. 3 and 4, in the preferred embodiment of the present invention, the ice maker assembly  34  includes a tool removable fan assembly  60  attached to the front face  56  of the housing of the ice maker assembly. The fan assembly  60  is preferably a modular unit containing all of the components, as described hereinbelow, required to provide timed increased airflow to the ice making apparatus such as to produce an optimal ice production rate. Providing a modular design for the fan assembly  60  allows an ice maker to be assembled without the fan assembly and instead using an alternate end decorative and safety cover  60   a,  shown in FIG.  3 A and similar to the cover shown in FIG. 1 of Guess &#39;165. This permits efficient simultaneous production of both a conventional ice maker assembly such as that shown in Guess &#39;165 and a high production ice maker assembly  34 . The modular design further permits the fan assembly  60  to be offered commercially as an optional upgrade to certain conventional ice maker assemblies. 
     The fan assembly  60  has a housing, preferably formed of a suitable plastic material, having a top wall  62 , a side wall  64 , a side wall  66 , a bottom wall  68 , and a front wall  70 . The fan assembly  60  is removably mounted to the front face  56  of the housing of the ice maker assembly  34  by means of cooperating mounting structures  90  and  92  of the front face of ice maker assembly and the fan assembly, respectively. Preferably, the cooperating mounting structures require a tool for removal to inhibit removal except by repair technician. When removably mounted to the front face  56  of the housing of the ice maker assembly  34 , the top wall  62 , bottom wall  68 , and side walls  64  and  66  are substantially aligned with the outer dimensions of the ice maker assembly  34 , and substantially blocks the ice maker assembly, except for the bin lever arm  54 , from elevation view by a user of the freezer compartment  14 . 
     As best shown in FIGS. 4 and 7, a fan switch  72  is mounted to the front wall  70  of the fan assembly for selective operation of the fan assembly in a manner described later herein. One pole of the switch  72  is connected within the housing of the fan assembly  60  by a wire  74  to a first pin  76  projecting rearwardly from the fan assembly and adapted for selective electrical engagement with the ice maker control circuit  116  of the ice maker assembly  34  in a manner to be described shortly. Another pole of the switch  72  is connected by a wire  78  to one pole of a fan motor  80 . The second pole of he fan motor is connected by a wire  82  to a second pin  84  projecting outwardly and rearwardly from the interior of the fan assembly  60  and adapted for selective electrical engagement with the ice maker control circuit  116  of the ice maker assembly  34 . 
     As shown schematically in FIG. 7, the first and second pins  76  and  84  are designed to engage mechanically and electrically with respective connection points  86  and  88  on the front face  56  of the housing (See also FIG. 6) of the ice maker assembly  34  such as to place the fan motor  80  and the fan switch  72  in series with main switch  46  of the ice control circuit. Thus, the fan motor  80  will only operate when both the ice making apparatus  50  is operating to make ice and the fan switch is set to permit the fan motor to operate. Preferably, as shown in FIG. 7, the fan motor  80  is also in series with the bail arm switch  58  so that it will cease operating when the bail arm is raised. This is preferred because, as is well known in the art, the bail arm is raised when the ice maker is in a harvesting mode and the heater is operated to loosen the ice bodies from the molds  52 . It is less efficient to provide air movement across the molds during harvest because it disperses the heat that is intended to be focused on separating the ice bodies and thereby interferes with the process and unnecessarily adds heat to the freezer compartment. 
     Referring back to FIG. 4, the fan motor  80  drives a shaft  92  coupled to a blower wheel  94  rotatably disposed with an enclosure  96  formed within the housing of the fan assembly  60  adjacent the side wall  66  adjacent the open region  44  above the ice storage bin  36 . An air inlet aperture  98  is provided into the enclosure  96  through the side wall  66 . The air inlet aperture  98  has a openings of a preselected configuration, size and shape suitable to permit sufficient airflow while minimizing the risk of damage or unintentional entry of objects. It is critical that the air inlet apertures  98  be clear of obstructions. Thus, in both embodiments described herein, the inlet is placed toward the inside of the product above the ice to minimize the chance obstruction. 
     The fan assembly  60  is further provided with an elongated snout  106  extending from the bottom wall  68  rearwardly and downwardly towards the region below the molds  52  and providing therein a passageway  102  communicating at one end with the enclosure  96  and at the other end with an outlet aperture  104  adjacent and below the molds  52  such that, when the fan motor  60  is operating, the blower wheel draws air through the inlet aperture  98  and delivers it out the outlet aperture  104  to the molds  52 . The snout  96  extends substantially along the entire width of the bottom wall  68  so as to provide an elongate outlet aperture  104  except that it is designed to clear the guide  38  and side wall of the ice storage bin  36 . 
     FIG. 5 shows a preferred method of constructing the fan assembly  60  by constructing the housing from three frame members  108   a,    108   b  and  108   c.    
     Referring now to FIGS. 8 and 9, an alternate ice maker assembly  34 ′ is illustrated wherein an alternate fan assembly  60 ′ is provided at the rearward portion of the open region  44  such as to selectively direct a flow of forward and towards the molds  152 . In this embodiment, the fan assembly  60 ′ has a top wall  62 ′, a side wall  64 ′, a side wall  66 ′, a bottom wall  68 ′, a front wall  70 ′ and a rear wall  72 ′. A conventional axial fan,  94 ′ driven by a motor  80 ′ draws air through an appropriate inlet aperture  98 ′ in the rear wall  72 ′ and pushes it out through a suitable outlet aperture  104 ′ in the front wall  70 ′. A fan switch  72 ′ and first and second pins  76 ′ and  84 ′ are provided on the cover  60 ′ and are electrically connected to the fan in a manner similar to that shown schematically in FIG. 7 by wires, not shown, disposed within the freezer walls in a manner well known in the art. FIG. 8 also schematically illustrates an ice bin  36 ′ of the type well known in the art adapted for cooperation with an ice dispensing mechanism through the freezer door  26 . 
     Please note that in both embodiments described herein, the air is supplied to the bottom of the ice maker assembly  34  and  34 ′ to prevent voids in the ice bodies. This also allows the air in the water to escape through the top of the ice bodies prior to freezing and gives a better “ice cube” without voids, cracks and improves clarity. Please also note that the air should not be supplied to near the bi-metal switch as it will cause the ice maker to cycle prematurely and could cause voids and cracks in the ice body to occur. Maximum efficiency occurs when air is supplied to the ice body next to the bi-metal switch and directed away from the bi-metal switch. The snout  106  of the preferred embodiment was designed to function as a nozzle in order to direct the airflow to this precise location, which can vary between ice maker designs. 
     The fan assembly of the present invention has been shown in use to produce and increase of 40 to 80% in the number of ice production cycles and therefore the number of cubes and the weight of ice produced daily, depending on the design of the refrigerator and the ambient conditions. 
     When incorporating the present invention into an existing refrigerator design, it must be appreciated that a higher rate of ice production means that a large capacity compressor may be needed to handle the additional heat load from, cooling the extra water into ice, operating the fan motor, and increasing the use of the ice maker heater. 
     The above description includes the best mode contemplated by the inventors for carrying out the present invention and is not intended to limit the scope of the invention to the specific example illustrated except where explicitly stated herein or in the claims. What is claimed as novel is as follows.