Patent Abstract:
A compact refrigerator has a split cabinet defining insulated refrigerator and clear ice maker sections. Its refrigeration system includes one external compressor and condenser and two evaporators, one for each section. The condenser is coupled to the inlet of the ice maker evaporator by a capillary tube and the evaporators are connected in series via a line having a refrigerator valve. The compressor receives return refrigerant from the outlet side of either the refrigerator evaporator or the ice maker evaporator depending on the state of a bypass valve, which is closed when the refrigerator valve is open, and vice versa. Refrigerant is thus routed to the ice maker evaporator to make ice and to both the ice maker and refrigerator evaporators when the refrigerator needs cooling. A hot gas bypass valve allows pre-condensed refrigerant exiting the compressor to bypass the condenser and be routed to the ice maker evaporator for harvesting the clear ice cubes.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     Not applicable.  
       STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable.  
       BACKGROUND OF THE INVENTION  
       [0003]     1. Technical Field  
         [0004]     The present invention relates to refrigerators and clear ice makers.  
         [0005]     2. Description of the Related Art  
         [0006]     Refrigerators and coolers for the cold storage of food and beverage items are well known. Typical residential ice makers form ice cubes by depositing water into a mold attached to an evaporator or the freezer compartment and allowing the water to freeze in a sedentary state. Such an approach results in clouded ice cubes as a result of the entrapped air and impurities in the water.  
         [0007]     It is known that forming ice by flowing water over a freezing surface will eliminate the clouding associated with sedentary freezing. Such a flowing water process has typically been used in commercial ice cube makers. One example of the flowing water approach is shown in U.S. Pat. No. 5,586,439; this patent and all others mentioned herein are hereby incorporated by reference as though fully set forth herein. In this patent, water is flowed over a vertically disposed evaporator plate whose surface defines pockets. The water cascades over the surfaces of the pockets and an ice cube is formed in each pocket. The ice cubes are harvested by passing hot vaporous refrigerant through the evaporator in place of the cold refrigerant. The resulting ice cubes are nearly transparent and not cloudy due to the particulate contaminates in the water being heavier than the water and falling from the evaporator before freezing and forming part of the ice cube. U.S. Pat. Nos. 6,058,731 and 6,148,621 disclose compact clear ice maker units incorporating such cascading water evaporator plates.  
         [0008]     These machines are separate from conventional full-size or compact refrigerators. It is well known for the freezer sections of some of these conventional refrigerators to include ice makers of the regular, non-clear, variety. U.S. Pat. No. 4,872,317 shows and describes a refrigeration unit having a built-in conventional type ice maker. As is conventional, this patented unit includes a molded tray type ice maker in the freezer section of the unit with a mechanical actuator to dispense and harvest the ice. Such ice makers are used in conventional refrigeration units because they are self contained, needing only a water supply line, and because they can produce ice in a unit having only one evaporator that cools both the freezer and refrigerator compartments.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention is combination refrigerator and clear ice maker, preferably of the compact, under-counter type. The invention provides a single refrigeration unit having a divided cabinet with a refrigerator side and a clear ice making side incorporating a flowing water system for producing clear ice, wherein each side has a dedicated evaporator. “Clear ice” is a common and accepted term in the refrigeration industry which is generally used to refer to ice formed in layers without the entrapped air, mineral and other particulates common in tap water which have a tendency to cause odor and to cloud the water when frozen.  
         [0010]     Specifically, the invention provides a refrigerator with clear ice making capability including a cabinet defining an interior refrigerator chamber and an interior ice maker chamber isolated from the refrigerator chamber by a partition wall. A clear ice maker mechanism is disposed in the ice maker chamber and includes an evaporator plate defining a plurality of pockets over which water cascades and in which clear ice pieces are formed. A refrigeration system includes an ice maker evaporator disposed in the ice maker chamber adjacent the evaporator plate and a refrigerator evaporator disposed in the refrigerator chamber. The evaporators are coupled to a compressor receiving return refrigerant from the evaporators and to a condenser coupled to the compressor.  
         [0011]     In a preferred form, the cabinet has a front opening leading to the ice maker chamber and the refrigerator chamber that is closed by a door hinged to the cabinet along one side. The door has a special seal designed to extend along the front face of the cabinet, along the top, bottom, side and partition walls. An insulated body in the ice maker chamber defines an ice bin receiving harvested ice pieces from the ice maker mechanism. The seal has a small cross-piece that seals off an opening to the insulated body in the ice maker chamber when the door is closed. The seal thus isolates the ice from the ambient and the heat from the refrigeration system in the uninsulated compartment of the refrigerator by preventing hot air from passing between the door and an uninsulated lower panel in the front of the ice maker chamber (where the user control is mounted) and into the opening of the insulated body.  
         [0012]     Preferably, the evaporator plate has a plurality of spaced vertical members and a plurality of spaced horizontal members intersecting the vertical members at right angles to define the pockets. The horizontal members extend downwardly from a rear edge to a front edge at an oblique angle to so that water flowing onto the evaporator plate can cascade down the evaporator plate and so that the ice cubes can drop under gravity from the evaporator plate when harvested. A water distributor is disposed above the evaporator plate for distributing water over the full width of the evaporator plate so as to run over all of the pockets therein. An end of a water tube is mounted to the center of the distributor by a tube retainer havening an opening and an inverted partial cup section mating with a centering section of the distributor.  
         [0013]     The water tube provides fresh water supply and runs from a water sump mounted in the ice maker chamber beneath the evaporator plate in which is disposed a water pump circulating water from the sump through the water tube back to the ice maker evaporator plate. An overflow mechanism is also provided that is connected to a drain leading out of the cabinet. The overflow drain can be connected to an optional condensate or waste drain pump and overflow collector having two floats, one disposed vertically above the other. The lower float operates a switch to activate the drain pump to drain the overflow collector and the upper float can disrupt the ice maker capability and activate an indicator light in the event the drain line backs up. The indicator light preferably stays on until power to the refrigerator is disrupted, which is intended to provide the user or field technician indication of a prior or current error condition.  
         [0014]     In an even more preferred form, the evaporators are connected in series, and the refrigerator evaporator receives refrigerant passing through the ice maker evaporator. A refrigerator valve controls flow of refrigerant from the ice maker evaporator to the refrigerator evaporator, and a bypass valve controls flow of refrigerant from the ice maker to the compressor when the refrigerant valve is closed. These valves are preferably solenoid operated and electronically controlled so that during operation of the refrigerator at least one of the valves is open while being interlocked so that both of the valves cannot be open or closed concurrently.  
         [0015]     In other preferred forms, another bypass valve is disposed between an outlet side of the compressor and the inlet side of the ice maker evaporator so that when open it routes pre-condensed (hot) refrigerant from the compressor to the ice maker evaporator and bypasses the condenser. This hot gas bypass valve is closed during normal operation of the refrigerator and is opened during an ice harvest cycle so as to warm the evaporator plate slightly to melt the interface between the ice cubes and the evaporator plate so that they can be dispensed into the ice bin.  
         [0016]     The refrigerator of the present invention has an electronically controlled refrigeration system operating automatically according to temperature readings taken from temperature sensors located at various locations in the cabinet, including at the ice bin, the refrigerator and a liquid refrigerant line, to operate in one of four primary modes in addition to an inactive state, water fill modes and a cleaning mode. In particular, if, based on the temperature readings, cooling is needed in the refrigerator section and more ice is needed in the ice bin, then the system operates in a dual cooling mode in which the circulation pump is energized to supply water to the ice maker evaporator plate and the refrigerator valve is opened (and the refrigerator bypass valve is closed) so that refrigerant is supplied to the ice maker evaporator and the refrigerator evaporator. When the ice maker bin temperature is within the set range, but the refrigerator section needs cooling, the system enters refrigeration only mode in which the refrigerator and refrigerator bypass valves stay the same as the dual cooling mode so that refrigerant is supplied to the ice maker evaporator and the refrigerator evaporator, however, the water pump is not energized so that water does not flow to the ice maker evaporator plate. No ice is formed then, but additional cooling will occur in the ice maker chamber as a result of the refrigerant flow through the ice maker evaporator, but this is acceptable given that only ice is stored or formed in this chamber. In an ice making only mode, the refrigerator valve is closed and the bypass valve is opened so that refrigerant is supplied to the ice maker evaporator, but not to the refrigerator evaporator. The water pump is also energized to run water over the ice maker evaporator plate, preferably for a time period determined according to the liquid refrigerant line temperature sensor. In an ice harvest mode, the hot bypass valve is opened to divert away from the condenser the hot pre-condensed refrigerant from the compressor to the ice maker evaporator. This warms the ice maker evaporator plate and causes melting at the interface of the ice cubes to allow them to drop down into the ice bin. As mentioned, the refrigeration system can also be in inactive in which the compressor and condenser are not operating so that no refrigerant is supplied to either the ice maker evaporator or the refrigerator evaporator. The unit can be switched to a cleaning mode in which the ice maker water pump and water fill valve are energized alternately to fill and pump water over the ice maker evaporator plate without condensed refrigerant in the ice maker evaporator.  
         [0017]     These and still other advantages of the invention will be apparent from the detailed description and drawings. What follows is a preferred embodiment of the present invention. To assess the full scope of the invention the claims should be looked to as the preferred embodiment is not intended as the only embodiment within the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a perspective view of the compact combination refrigerator and clear ice maker unit of the present invention;  
         [0019]      FIG. 2  is a perspective view thereof showing a front door opened;  
         [0020]      FIG. 3  is a front plan view thereof of shown with the front door removed;  
         [0021]      FIG. 4  is a side view sectional view showing the ice maker section of the refrigerator;  
         [0022]      FIG. 5A  is an exploded perspective view of the unit without the door;  
         [0023]      FIG. 5B  is another exploded perspective view of the unit;  
         [0024]      FIG. 5C  is a perspective view of a clear ice maker mechanism;  
         [0025]      FIG. 5D  is a perspective view showing the insulated interior insert of the ice maker section of the unit;  
         [0026]      FIG. 6  is a partial perspective view showing a special door seal;  
         [0027]      FIG. 7  is an enlarged view of the clear ice maker;  
         [0028]      FIG. 8  is a perspective view of the clear ice maker;  
         [0029]      FIG. 9  is a partial enlarged view of a water tube retainer attaching a water tube to a distributor section of the clear ice maker;  
         [0030]      FIG. 10  is a partial front view showing the water tube retainer;  
         [0031]      FIG. 11  is a partial cross-sectional view taken along line  11 - 11  of  FIG. 7 ;  
         [0032]      FIG. 12  is an enlarged section view of the water tube retainer;  
         [0033]      FIG. 13  is a schematic diagram of the refrigeration system for the refrigerator when in a water fill mode and when refrigeration and ice are required;  
         [0034]      FIG. 14  is a schematic diagram of the refrigeration system in a water fill mode when no refrigeration is required;  
         [0035]      FIG. 15  is a schematic diagram of the refrigeration system when in an ice making and refrigeration mode;  
         [0036]      FIG. 16  is a schematic diagram of the refrigeration system when in an ice making only mode;  
         [0037]      FIG. 17  is a schematic diagram of the refrigeration system when in a refrigeration only mode;  
         [0038]      FIG. 18  is a schematic diagram of the refrigeration system when in an ice harvest (no refrigeration) mode;  
         [0039]      FIG. 19  is a schematic diagram of the refrigeration system when all sub-systems are satisfied;  
         [0040]      FIG. 20  is a schematic diagram of the refrigeration system when in a cleaning (no refrigeration) mode; and  
         [0041]      FIG. 21  is a diagram of the user control and interface for the refrigeration system. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0042]     Referring to  FIGS. 1-6 , a combination refrigerator and clear ice maker  30  (“combination unit  30 ”) includes a cabinet  32  defining a cavity with a forward opening  34  that is divided by a partition wall  36  into a refrigerator section  38  and an ice section  40 . The refrigerator section  38  is simply a rectangular chamber, preferably providing about 2.5 cubic feet of cool storage space, with pairs of vertically spaced grooves for supporting edge encapsulated glass panel shelves  42 . Along the back wall of the refrigerator section  38  is a thin refrigerator evaporator  44  with internal refrigerant passages, which is part of the refrigeration system of the combination unit  30 , discussed below. The ice section  40  is a similarly sized chamber having a foam insulated, molded insert  45  containing a clear ice maker assembly  46  and defining an access opening  62  and a lower ice storage bin  64  (see  FIG. 5D ).  
         [0043]     The cabinet opening  34  is closed by a door  48  that is hinged to the cabinet  32  (with self-closing cams) along one vertical side thereof. Both the cabinet  32  and door  48  are formed of inner molded plastic members and outer formed metal members with the space filled with an insulating layer of foam material, all of which is well known in the art. The door  48  has a full-width handle  50  along a top edge of a special construction to allow the door to accept an overlay panel (not shown) matching the cabinetry where the unit is installed. Details of such an overlay panel and a preferred handle construction can be found in co-owned pending application Ser. No. 10/076,746, filed on Feb. 14, 2002. As shown in  FIGS. 5B and 6 , the inside of the door  48  can have one or more door shelves  52 , and vertical supports therefor preferably being formed as an part of the molded plastic interior of the door  48 . A wrap around front and bottom portion of the shelves  52  is preferably removable from the door  48  so that the containers or other items stored thereon can be transported by the removable portion of the shelves  52 .  
         [0044]     A rubber accordion type refrigerator gasket  54  is mounted to the inside of the door  48  to thermally isolate the refrigerator section  38  and the ice section  40  from each other and the ambient exterior to the combination unit  30  when the door  48  is closed against the cabinet  32 . The gasket  54  is specially configured with a vertical segment  56  near the horizontal center of a rectangular frame  58  so as to seat against the front edge of the partition wall  36 , in addition to the frame  58  seating against the front edges of the top, bottom and side walls of the cabinet  32 , when the door  46  is closed. The gasket  54  also has a shorter horizontal cross segment  60  that seats against a front panel of the ice section behind which is the insulated insert  45  (and ice bin  64 ) containing clear ice pieces harvested from the clear ice maker assembly  46 .  
         [0045]     Referring now to FIGS.  5 C and  7 - 8 , the clear ice maker assembly  46  is riveted to the partition wall  36  in the upper part of the ice section  40  of the cabinet  32 . The clear ice maker assembly  46  includes a metal evaporator grid  70  mounted in a plastic shroud  72 . The evaporator grid  70  has a series of vertical and horizontal dividers  70   a  and  70   b,  respectively, which extend from a rear wall  74  and between lateral edges to divide the evaporator grid  70  into a series of pockets. As best shown in  FIGS. 7 and 8 , the horizontal dividers  70   b  slope towards the bottom front of the evaporator grid  70 .  
         [0046]     The shroud  72  is formed of a plastic material such as a polypropylene or ABS and is molded about the evaporator grid  70 . The shroud  72  has a continuous bulbous edge  75  (see  FIG. 11 ) which engulfs the edges of the evaporator grid  70 . The shroud  72  has laterally extending wing portions  76  and  78  projecting from each end of the evaporator grid  70 . A bib portion  80  of the shroud  72  is disposed beneath the bottom edge of the evaporator grid  70  and contains integral projecting deflector fins  82 . Each deflector fin  82  is aligned with the center of a column of pockets in the evaporator grid  70 .  
         [0047]     The shroud  72  also includes an inclined roof  86  disposed above the evaporator grid  70 . A water distributor  88  is attached to the shroud wings  76  and  78  above the roof  86 . As shown in  FIGS. 8, 9 ,  11  and  12 , the distributor  88  has a floor  90  with a central well  92  at one edge. Spaced upright barriers  94   a  and  94   b  extend from the floor  90  beyond the well  92 . A second series of spaced barriers  96   a,    96   b,  et. sec. extend between the barriers  94   a  and  94   b  and a rear edge  98  of the floor  90 . Water deposited in the well  92  will be directed by the barriers  94  and  96  to flow uniformly over the rear edge  98  and on to the inclined roof  86 . The water will thereafter flow over the roof  86  of the shroud  72 , and into and over the surfaces of the pockets in evaporator grid  70 . As shown in  FIGS. 8-12 , uniform distribution of the water is further ensured by a guide  100  that has a top opening  102  that receives an end of a water tube  103  and a cylindrical wall section  104  that fits around a portion of the well  92 . The guide  100  fixes the water tube  103  at the middle of the distributor  88 . The water tube is also secured in place by a rivet  106  connection to the top of the cabinet  32 .  
         [0048]     An icemaker evaporator  108  is attached to the rear wall  74  of the evaporator grid  70 . The icemaker evaporator  108  is a part of the refrigeration system shown schematically in  FIGS. 13-20 , which also includes the refrigerator evaporator  44  mentioned above.  
         [0049]     Generally, the refrigerator evaporator  44  has an outlet line  110  which passes through an accumulator  112  to a compressor  114 . The accumulator  112  functions in part as a reservoir for liquid refrigerant so that only gas is fed to the compressor  114 . A discharge line  116  connected to the outlet of the compressor  114  is connected to the inlet of a condenser  118  having an outlet line  120  connected to a dryer  122 . A capillary tube  124  leads from the dryer  122  to the inlet of the icemaker evaporator  108 . A bypass line  126 , having a hot gas bypass valve  128 , runs between the compressor discharge line  116  and an inlet of the icemaker evaporator  108 . The icemaker evaporator  108  has a branched outlet line  130  connected to an inlet of the refrigerator evaporator  44  and to the accumulator  112 , such that the evaporators  44  and  108  are connected in series with the refrigerator evaporator  44  receiving refrigerant passing from the ice maker evaporator  108 . A refrigerator valve  132  controls communication between the icemaker evaporator  108  outlet and the refrigerator evaporator  44  inlet and a refrigerator bypass valve  134  controls communication between the icemaker evaporator  108  outlet and the accumulator  112 . All of the valves  128 ,  132  and  134  are electronically controlled, preferably solenoid type valves. Valves  132  and  134  are interlocked by a double throw relay which requires one of these valves  132  and  134  to always be open while preventing both from being concurrently open or closed.  
         [0050]     As is known, the compressor  114  draws refrigerant from the refrigerator evaporator  44  (and ice maker evaporator  108 ) and accumulator  112  and discharges the refrigerant under increased pressure and temperature to the condenser  118 . The hot, pre-condensed refrigerant gas entering the condenser  118  is cooled by air circulated by a fan  136 . As the temperature of the refrigerant drops under substantially constant pressure, the refrigerant in the condenser  118  liquefies. The smaller diameter capillary tube  124  maintains the high pressure in the condenser  118  and at the compressor outlet while providing substantially reduced pressure in the ice maker evaporator  108 . The substantially reduced pressure in the ice maker evaporator  108  results in a large temperature drop and subsequent absorption of heat by the ice maker evaporator  108  (and also possibly the refrigerator evaporator  44 ).  
         [0051]     As mentioned, the refrigeration system includes a hot gas bypass valve  128  disposed in bypass line  126  between the outlet of the compressor  114  (via discharge line  116 ) and the inlet of the icemaker evaporator  108 . When the hot gas bypass valve  128  is opened, hot pre-condensed refrigerant will enter the icemaker evaporator  108 , thereby heating the evaporator grid  70 . Such a hot gas bypass system is described in U.S. Pat. No. 5,065,584 issued Nov. 19, 1991, for “Hot Gas Bypass Defrosting System”.  
         [0052]     The compressor  114 , condenser  118 , and fan  136  are located at the bottom of the cabinet  32  beneath the insulated portion, as shown in  FIGS. 4 and 5 A- 5 B.  
         [0053]     Referring to  FIGS. 4 and 8 , a water sump  138  has a trough portion  140  extending beneath the evaporator grid  70  of the clear ice maker assembly  46 . The bottom of the trough portion  140  slopes downwardly to the level of a well  142  in which the inlet  144  of a water pump  146  is mounted. The outlet of the water pump  146  is connected to the well  92  in the distributor  88 . A removable stand pipe  148  extends into the sump  138  and leads to an overflow pipe  150 . The overflow pipe  150  opens to a drain  152  in the bottom of the bin area of the insert  45  within the ice section of the cabinet  32 . Thus, water from the sump  138  and any melted ice within the ice bin  64  can drain through the drain  152 . The drain  152  can be connected to a drain in the home plumbing, or it may lead to an overflow collector  182  (discussed below) in the space beneath the insulated portion of the cabinet  32 . Fresh water from an external source may be provided periodically to the sump  138  through a water fill valve  156  (see  FIGS. 6 and 13 ).  
         [0054]     In general operation, water from the sump  138  is pumped by the pump  146  to the distributor  88  which delivers a cascade of water over the surfaces of the evaporator grid  70 . When the icemaker evaporator  108  is connected to receive liquefied refrigerant from the condenser  118 , the water cascading over the surface of the evaporator grid  70  will freeze forming cubes of clear ice in the pockets. The pure water freezes first and impurities and trapped air in the water will either escape or be left in suspension in the flowing water. Once the ice cubes are formed, the hot gas bypass valve  126  is opened and hot refrigerant is delivered to the icemaker evaporator  108 , thereby warming the surface of the evaporator grid  70  until the ice cubes dislodge from the evaporator grid  70 . The dislodged ice cubes will fall into the bin  64  and are directed away from the trough portion  140  of the sump  138  by the fins  82 . As mentioned, not all water cascading over the surface of the evaporator grid  70  will freeze. The excess water is collected in the trough  140  and returned to the well  142  where it is recirculated to the distributor  88  by the pump  146 . During ice harvest (after each freezing cycle), a charge of fresh water is delivered to the sump by the water fill valve  156  to dilute the water and flush impurities through the overflow pipe  148  and out the drain.  
         [0055]     Although not shown, the combination refrigerator and clear ice maker  30  includes an electrical system for controlling the operation of the compressor  114 , solenoids for valves  128 ,  132  and  134 , the condenser fan  136 , the water pump  146 , and a solenoid that controls the fresh water inlet valve  156 . The operation of the motors and solenoids are controlled by a microprocessor based control that operates by programmed logic and in response to sensor and user input. The programmed logic, for example, provides a timed shut down cycle (e.g., four minutes) following every operation of the compressor. The control circuitry is also designed with various built-in technician diagnostic capabilities to provide on board testing of electrical subsystems.  
         [0056]     The electric system includes three sensors, or thermistors including a bin thermistor (not shown) disposed near the upper side of the ice bin  64 , a refrigerator thermistor (not shown) disposed in the refrigerator section of the cabinet  32 , and a liquid line thermistor (not shown) disposed in the outlet line  120  of the condenser  118 . The thermistors are conventional parts commercially available, for example, from Royal Philips Electronics of Amsterdam, The Netherlands. An optional overflow circuit (described below) also provides feedback to the control as to the status of the drain. A user control  160  disposed in a front panel at the lower ice maker side of the cabinet  32  and a toggle switch  162  located at the cabinet front grille  161  provide input from the user. The toggle switch  162  is a three-position switch for turning the system to “on”, “off” or “clean” modes. The user control  160  (see  FIG. 21 ) has an LED display  164  for displaying the actual and desired or “set” temperatures and three LED indicator lights A, B and C described below. The user control  160  also includes “set temp”  170 , “warmer”  172  and “cooler”  174  push buttons.  
         [0057]     With reference to  FIGS. 13-20 , the operation of the combination unit  30  will now be described. On initial start-up or restarting with the bin thermistor closed, the toggle switch  162  is placed into the “on” position to energize the unit. Depending on whether the refrigerator section is warmer than the temperature set point of the control, which defaults at 38° F., the refrigeration system will operate as shown in either  FIG. 13  or  FIG. 14 .  FIG. 13  illustrates the normal operation at initial startup since ordinarily the refrigerator section will be warmer than desired. In this case, turning the toggle switch to on will energize the solenoids for the refrigerator valve  132  and the water inlet valve  156 . This will also energize the compressor  114  and the condenser fan  136  to being circulating refrigerant through both refrigerator  44  and the icemaker  108  evaporators. This initial water fill mode will continue for a period of time, such as three minutes, regardless of the status of the bin and refrigerator thermistors, in a preferred form of the control logic. As shown in  FIG. 14 , if the refrigerator section is at or below the set temperature at startup, for example, because of recent operation, cold product stored in the refrigerator section, or cold ambient temperatures, then the water fill mode will run as shown in  FIG. 14  when the toggle switch  162  is turned to on, in which only the solenoids for the water fill valve  156  and the refrigerator bypass valve  134  are energized for the set period of time.  
         [0058]     Once the initial water fill cycle is complete, the unit will enter one of three modes: ice making and refrigeration mode ( FIG. 15 ), ice making only mode ( FIG. 16 ), or refrigeration only mode ( FIG. 17 ). Again, because at initial startup the refrigerator section is ordinarily warmer than the set temperature and there is no ice in the bin  64 , the unit will normally enter the ice making and refrigeration mode illustrated in  FIG. 15 . As shown, here the bin thermistor is calling for ice and the refrigerator thermistor is calling for cooling. In this mode, the compressor  114 , condenser fan  136  and water pump  146  are energized as is the solenoid for the refrigerator valve  132 . Refrigerant will circulate through both of the refrigerator  44  and icemaker  108  evaporators to cool the refrigerator section and the evaporator grid  70  of the clear ice maker assembly.  
         [0059]     After a certain predetermined period of time into this cycle, such as four minutes, a reading of the liquid refrigerant temperature sensed by the line thermistor is taken. This temperature reading will determine the remaining length of time for the ice making portion of the cycle and may also be used to set or adjust the duration of the ice harvest cycle. The higher the temperature of the liquid refrigerant, the longer the ice making cycle. For example, if the liquid refrigerant temperature is 80° F., the total freeze time will be about 14 minutes. If the sensed temperature is 100° F., the total freeze time will be about 22 minutes. At a temperature of 120° F., the freeze time will be about 30 minutes.  
         [0060]     The control is preferably programmed so that once an ice making cycle has been initiated, the cycle will continue to completion through ice harvest regardless of thermistor readings. This prevents the ice making cycle from terminating prematurely thereby ensuring that full-sized ice cubes are formed. At initial startup the control is also preferably programmed to complete a first set of ice cubes without regard to the refrigerator thermistor reading. Once that initial ice is made, and following subsequent ice harvest cycles, the control will check the refrigerator thermistor reading to determine if the refrigerator section is above the higher of a predetermined refrigerator limit temperature, such as 42° F. or the set temperature. If so, the unit will enter refrigeration only mode, illustrated in  FIG. 17 , even if the ice bin thermistor is calling for more ice. Note that after the first ice cycle, ice making is preferably suspended until the refrigerator section reaches 42° F., or some user set higher temperature. In the refrigeration only mode, the compressor  114  and the condenser fan  136  are energized and the water pump  146  is de-energized while the refrigerator valve  132  remains energized. The unit will continue in this mode until the refrigerator section reaches the limit temperature (42° F.) or a higher user set temperature following the first ice cycle. At that point, if the temperature in the refrigerator section is lower than the limit temperature, then the ice making and refrigeration mode will resume, unless the temperature in the refrigerator is below the set temperature in which case the unit will enter the ice making only mode illustrated in  FIG. 16 , assuming in both cases that the bin thermistor is calling for ice. In the ice making only mode the compressor  114 , condenser fan  136 , water pump  146  and the solenoid for the refrigerator bypass valve  134  are energized. Because of the interlocking architecture, opening of the refrigerator bypass valve  134  closes the refrigerator valve  132  so that no refrigerant passes through the refrigerator evaporator  44 . A water fill cycle, as illustrated in FIGS.  13  or  14  (depending on conditions), will be initiated after the ice bin thermistor has been satisfied, when the ice bin has been filled and then again calls for ice. This can occur when the refrigerator side is cooling ( FIG. 13 ) or not ( FIG. 14 ). If the refrigerator side is cooling when the fill cycle is initiated, the control is programmed to maintain refrigerator cooling until the water fill cycle is completed, regardless of the reading of the refrigerator thermistor.  
         [0061]     When the ice making cycle is completed, the unit enters ice harvest mode, as illustrated in  FIG. 18 , in which the compressor  114  remains energized while the water pump  146  and condenser fan  136  are de-energized and the solenoids for the hot gas bypass valve  128  and the water inlet valve  156  are energized. The solenoid for the refrigerator bypass valve  134  is also energized so that no cooling of the refrigerator section is possible during ice harvest. The hot refrigerant gas flowing through the icemaker evaporator  108  will loosen the ice formed in the pockets of the evaporator grid  70  so that the ice can fall into the ice bin  64 . As mentioned, the length of the ice harvest cycle can be dependent upon the reading of the liquid line thermistor. The length of the harvest cycle would thus be adjusted inversely based upon the sensed temperature. The harvest cycle can also be made constant for a range of temperatures or entirely independent of the liquid line thermistor. A typically harvest cycle lasts approximately 2-3 minutes.  
         [0062]     If the bin thermistor calls for additional ice at the conclusion of the ice harvest cycle, the control enters to a new ice cycle with the compressor, water pump, and condenser fan all energized and with the hot gas and water inlet solenoids de-energized. Once the bin thermistor opens, when the bin is full of ice, the ice making and harvesting cycle will stop until the ice level is decreased.  
         [0063]     When both the refrigerator and bin thermistors have been satisfied, the unit enters the “all satisfied” mode illustrated in  FIG. 19 . Here, all systems and solenoids are de-energized, with the exception that the refrigerator bypass valve is energized. It should be noted that the control is preferably programmed with a two degree (F) set point tolerance (or four degree temperature differential) for the refrigerator thermistor to smooth out the refrigeration on and off cycles at or near the set temperature. For example, if the set temperature is 38° F., the refrigerator section will be cooled to 36° F. and will not re-initiate cooling until the refrigerator thermistor reads 40° F.  
         [0064]     The unit can also enter a clean mode, by moving the toggle switch  162  to a “clean” position, in which the control cycles through programmed wash, fill, and rinse cycles for cleaning the icemaker evaporator  108  and evaporator grid  70 . As illustrated in  FIG. 20 , in the clean mode the compressor  114  and condenser fan  136  are de-energized so that there is no refrigerant flow through the evaporators and the water pump  146  and solenoid for the water inlet valve  156  are energized and de-energized in alternating fashion to provide a charge of fresh water to the water pump which pumps the water over the ice maker grid. If desired, a cleaning solution can be added manually to the water and pumped through the clear ice maker assembly to improve cleaning.  
         [0065]     The refrigerator evaporator  44  remains frost free by clearing itself periodically. Since the refrigerator thermistor is not directly on the refrigerator evaporator, the control is programmed to run a thirty minute refrigerator off cycle for every twelve hours of clock time. In this case, the refrigerator section will not be cooled even if the refrigerator thermistor calls for cooling, however, the ice maker can operate as normal based on the bin thermistor reading.  
         [0066]     Referring now to  FIG. 21 , the user control  160  displays the set temperature of the refrigerator section on the LED display  164 , by pressing and the warmer  172  button the actual temperature can be shown on the display  164 , the indicator light A will illuminate solid at this time as well. The temperature of the refrigerator section can be adjusted by depressing the set temp button  170  momentarily and depressing the warmer  172  and cooler  174  buttons until the desired temperature is displayed. The displayed temperature will flash for a time period, such as  10  seconds, and the new set temperature will be stored in memory and the set mode will be exited and then the display will stop flashing.  
         [0067]     The three dot-like LED indicator lights  166 - 168  shown in the display window as either off, solid or flashing depending on the indicator light and status of the unit. These indicator lights give the user and the service technician feedback of the current status of the unit as well as prior or current error conditions, as summarized in Table 1 below.  
                             TABLE 1                           LED indications            LED   Status   Meaning               A   Solid   Actual refrigerator temperature displayed           Flashing   Not applicable       B   Solid   Service menu - will exit after wait 10 seconds           Flashing   Open thermistor - call for service       C   Solid   Service menu - will exit after 10 seconds           Flashing   Drain pump is blocked - check install and drain line                  
 
         [0068]     As mentioned, indicator light A will illuminate solid when the actual temperature of the refrigerator section is being displayed. This indicator light has no other function and does not flash. Indicator lights B and C illuminate solid when a service menu is activated. Depressing the cooler button  174  will illuminate indicator light B and the reading of the liquid line thermistor will be displayed. Keeping the cooler button  174  depressed will illuminate indicator light C and the bin thermistor reading will be displayed. By continuing to depress the cooler button  174 , the display will alternate between the liquid line and bin temperature readings.  
         [0069]     In the event that any one of the thermistor readings is out of the acceptable ranges, indicator light B will flash to indicate an error condition. If either the liquid line reading or the bin reading is out of range, the ice maker will shut down, but allow the refrigerator side to continue cooling, if necessary. If the refrigerator reading is out of range, the refrigerator side will shut down (by energizing refrigerator bypass valve  134 ) while allowing the ice maker side to continue operation. When the errant reading returns to an acceptable value, the unit will reinitiate operation of the affected system. The indicator light B will remain flashing, even after normal operation conditions have resumed, to provide the user and service technician with an indication that an error condition has occurred. This is to help for the technician diagnose the source of the problem, which in the case of a high liquid line temperature reading may be due to heavy loading, restricted airflow, or an unclean condenser, for example.  
         [0070]     The indicator light C will flash when an error condition has occurred in the drain line when an optional drain pump  180  and overflow collector  182  (see  FIGS. 5A and 5D ) are instilled, as needed in applications where a gravity assisted drain line cannot be accessed. In a preferred form, the drain pump  180  is actuated by a float controlled switch to periodically empty the collector  182  (and sump). A second float controlling another switch (not shown) is located in the collector  182  at a higher level that when tripped shuts down the ice maker (without effecting operation of the refrigerator section), by de-energizing or preventing energizing of the water pump and water fill valve. Tripping the second switch indicates that the drain pump  180  is not working or that there has been a blockage in the drain line. At this point, the indicator light C will begin flashing, and like indicator light B, the control is programmed to keep indicator light C flashing after normal operation has resumed to aid in service diagnostics. Both flashing indicator lights will remain flashing until power to the unit is disrupted, for example, by tripping a circuit breaker or unplugging the plug from the electrical outlet.  
         [0071]     It should be appreciated that merely a preferred embodiment of the invention has been described above. However, many modifications and variations to the preferred embodiment will be apparent to those skilled in the art, which will be within the spirit and scope of the invention. Therefore, the invention should not be limited to the described embodiment. To ascertain the full scope of the invention, the following claims should be referenced.

Technology Classification (CPC): 5