Abstract:
An auxiliary sensor can be used to measure the temperature of individual products in a heating cabinet. By arranging the temperature sensor with respect to the low mass thermal conductors and insulators, the sensor can be focused on the product to obtain the proper temperature irrespective of the immediate environment whether it is at room temperature or even within the heating cabinet.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. provisional application No. 62/316,972 filed Apr. 1, 2016 and hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to warming systems for medical fluids, and in particular, to a warming cabinet with an auxiliary temperature sensor separate from the temperature sensor of the warming cabinet. 
         [0003]    Warming cabinets for use in the medical industry are frequently used to maintain intravenous fluids at or near body temperature in order to maintain patient normothermia from admission to discharge. Maintaining the temperature and quality of intravenous fluids improves patient recovery, decreases blood loss, reduces surgical site infections, and reduces the length of hospital stays. 
         [0004]    While warming cabinets typically ensure that product in the cabinets is quickly brought up to the proper body temperature, product recently introduced into the cabinets may not have achieved the proper temperature, allowing undesirably cool product to be introduced into the patient. In addition, if product is returned to the cabinet, how long it needs to remain in the cabinet may be unclear. This is particularly a problem because recently introduced product may be toward the front of the cabinet. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides an auxiliary sensor that can be used to, measure the temperature of individual products in a heating cabinet. By arranging the temperature sensor with respect to the low mass thermal conductors and insulators, the sensor can be focused on the product to obtain the proper temperature irrespective of the immediate environment whether it is at room temperature or even within the oven. 
         [0006]    In one embodiment, the present invention may be an auxiliary temperature monitoring system for measuring the temperature of an IV bag held within a warming cabinet, the system comprising a housing having an internal cavity; a heater adapted to heat the internal cavity; a sensor detecting a temperature of the internal cavity; and an auxiliary temperature device comprising an auxiliary housing, a heat collection plate supported by the housing and having an upwardly exposed upper surface configured to support the IV bag therein, and an auxiliary sensor configured to approximate a temperature of the heat collection plate. 
         [0007]    It is thus a feature of at least one embodiment of the present invention to determine a temperature of an IV bag within a heating cabinet (or an IV bag just taken out of the heating cabinet) that is independent from the temperature reading of the interior cavity. 
         [0008]    A feedback control system may receive the temperature of the internal cavity to control activation of the heater. 
         [0009]    It is thus a feature of at least one embodiment of the present invention to utilize the heating cabinet heater for heating the IV bag but utilize the auxiliary temperature device for determining a temperature of the IV bag. 
         [0010]    The plate may be sized to contact at least 30 percent of the surface of an IV bag supported by the auxiliary housing. The heat collection plate may have an exposed area greater than 4 square inches or greater than 6 square inches. 
         [0011]    It is thus a feature of at least one embodiment of the present invention to allow the heat collection plate to quickly adjust to and equalize with the IV bag temperature when within the internal cavity. 
         [0012]    An entire lower surface of auxiliary housing beneath the heat collection plate may be insulated. 
         [0013]    It is thus a feature of at least one embodiment of the present invention to isolate measurement of the heat collection plate to an upper surface contacting the IV bag. 
         [0014]    The upper surface of the housing has opposed rails along opposite sides of the housing upper surface configured to retain an IV bag. 
         [0015]    It is thus a feature coat least one embodiment of the present invention to support the length and width of the IV bags in a manner which facilitates temperature sensing toward a center of the IV bag. 
         [0016]    An interior surface of the internal cavity has a releasable electrical connector adapted to receive a first end of a mating second electrical connector connected to the auxiliary temperature device. 
         [0017]    It is thus a feature of at least one embodiment of the present invention to take temperature readings while the IV bag is within the interior cavity to reduce heat loss or disruption within the internal cavity. 
         [0018]    The second electrical connector may communicate with the auxiliary temperature device through a flexible conductor. 
         [0019]    It is, thus a feature of at least one embodiment of the present invention to be able to take temperature readings from outside of the interior cavity, e.g., when space within the interior cavity is limited. 
         [0020]    An exterior surface of the housing may have a third electrical connector adapted to receive the second electrical connector wherein an opposite end is connected to the auxiliary temperature device. 
         [0021]    It is thus a feature of at least one embodiment of the present invention to be able to take temperature readings of medical product whether or not they are placed within the warming cabinet. 
         [0022]    A processor may operate a program stored in memory and communicate with the auxiliary sensor to determine an average temperature of the heat collection plate. 
         [0023]    It is thus a feature of at least one embodiment of the present invention to detect an average temperature about an entire area of the IV bag. 
         [0024]    The processor may operate a program stored in memory to communicate with a read out button to display the temperature of the auxiliary sensor on a warming cabinet display screen. 
         [0025]    It is thus a feature of at least one embodiment of the present invention to display an auxiliary temperature through the heating cabinet&#39;s built in controller and display screen. 
         [0026]    The processor may further operate the program stored in memory to communicate with a calibration button to compare the temperature of the warming cabinet sensor with the temperature of the auxiliary sensor and subtract a difference between the temperature of the sensor and the temperature of the auxiliary sensor from the temperature of the auxiliary sensor to calibrate the auxiliary sensor. 
         [0027]    It is thus a feature of at least one embodiment of the present invention to calibrate the temperature sensor prior to use to adjust for heat loss or external factors affecting the auxiliary sensor. 
         [0028]    The housing may be supported on feet extending downwardly from a bottom of the housing that are spaced apart to engage wire racks of the internal cavity therebetween the feet. 
         [0029]    It is thus a feature of at least one embodiment of the present invention to balance the housing on a wire rack without tilting the IV bag. 
         [0030]    The auxiliary temperature device may not have a heater. 
         [0031]    It is thus a feature of at least one embodiment of the present invention to provide a standalone temperature measurement device. 
         [0032]    The housing may be sized to contact less than 75 percent of a lower surface of the IV bag supported by the auxiliary housing. 
         [0033]    It is thus a feature of at least one embodiment of the present invention to insulate the heat collection plate from the oven racks while supporting the IV bag. 
         [0034]    The sensor may be bonded beneath the heat collection plate. 
         [0035]    It is thus a feature of at least one embodiment of the present invention to provide an accurate representation of plate temperature without heat loss therebetween. 
         [0036]    The heat collection plate may be a conductive metal. The heat collection plate may have a gauge thickness of less than or equal to 0.01 inches. 
         [0037]    It is thus a feature of at least one embodiment of the present invention to provide fast conduction of heat from the plate to the sensor. 
         [0038]    In one embodiment, the present invention may provide a method of detecting a temperature of an IV bag placed within a warming cabinet comprising a housing having an internal cavity; a heater adapted to heat the internal cavity; and a sensor detecting a temperature of the internal cavity, wherein the temperature is independent of the temperature of the warming, cabinet, and comprising the steps of: placing an auxiliary temperature device comprising an auxiliary housing, a heat collection plate supported by the housing and having an upwardly exposed upper surface configured to support an IV bag therein, and an auxiliary sensor configured to approximate a temperature of the heat collection plate within the warming cabinet; connecting the auxiliary temperature device to the warming cabinet; placing the IV bag on the heat collection plate: pressing the temperature read out button; and displaying the temperature of the heat collection plate on a display. 
         [0039]    These particular objects and advantages may apply to only sonic embodiments falling within the claims and thus do not define the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0040]      FIG. 1  is a cabinet projection of a warming cabinet of the present invention and used with an auxiliary temperature sensor connected at the inside of the cabinet and supported within a basket; 
           [0041]      FIG. 2  is a perspective view, viewed generally from above, of the auxiliary temperature sensor of  FIG. 1  with the connector disconnected from the cabinet; 
           [0042]      FIG. 3  is a cross section along line  3 - 3  of  FIG. 2  showing an outer housing supporting a bag of intravenous fluid thereon, a heat collecting plate contacting the bag, a temperature sensor mounted to the underside of the heat collecting plate, and an insulating layer surrounding the temperature sensor, and where the outer housing is stabilized on lateral rods of the warming cabinet basket; 
           [0043]      FIG. 4  is a block diagram of the functional components of the warming cabinet and the auxiliary temperature sensor in which the control provides a cabinet temperature or an auxiliary temperature; 
           [0044]      FIG. 5  is a flow chart of the steps of operation of the warming cabinet of  FIGS. 1-4  in implementing the present invention to selectively display the cabinet temperature of the cabinet sensor or auxiliary temperature of the auxiliary temperature sensor; and 
           [0045]      FIG. 6  is a flow chart of the steps of operation of the warming cabinet of  FIGS. 1-4  in implementing the present invention to calibrate the auxiliary temperature sensor. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0046]    Referring to  FIG. 1 , a warming system  100  may include a warming cabinet  102  to be used to warm a variety of items, such as intravenous fluids, blankets, and medicines and nutriments. The warming cabinet  102  may be generally rectangular and include a plurality of walls including a top wall  108  in parallel opposition to a bottom wall  110 . Left, right, and rear edges of the top wall  108  and bottom wall  110  are joined by a left wall  112 , a right wall  114  and a rear wall  116  which together define an interior warming chamber volume  120 . A door  118  is hingedly attached to the right wall  114  to be moved to a closed position sealing the interior warming chamber  120 . The door  118  also may be opened to access the interior warming chamber  120 . Latches  119  may be provided keep the door  118  closed and/or the door may include a spring biasing it toward a closed position. The door may also include a seal  121  (which may be a compressible gasket or the like) between the door  118  and the walls when the door  118  is closed. 
         [0047]    One or more shelves  123  may be arranged in the interior heating chamber  120  providing horizontally extending and vertically spaced support services subdividing the volume  120  to provide support for the items to be warmed therein or to increase the holding capacity of the cabinet  102 . The shelves  123  may be in the form of wire baskets  144  held on support ledges  142  extending inwardly from the interior of the walls of the cabinet  102 . The baskets  144  may be made of interwoven wires  194  or metal rods with longitudinal rods connected by transverse wires which are spaced at intervals from one another. The baskets  144  may be supported by the support ledges  142  at varying vertical distances so that two or more baskets  144  may be vertically spaced or stacked within the cabinet  102 . The baskets  144  can slide in and out of the interior heating chamber  120  to facilitate insertion and removal of the items within the baskets  144 . The baskets  144  may carry the items to be warmed, such as intravenous fluid bags  106 . 
         [0048]    As is understood in the art, the intravenous fluid bags  106 , shown in  FIG. 3 , may be constructed of a flexible transparent plastic material, such as a vinyl, and fabricated by joining two sheets  184  of the material at a peripheral scam  186  to provide within the seam  186  an enclosed pocket into which sterile infusion liquid  138  may be held. 
         [0049]    Referring to  FIG. 4 , the warming system  100  further includes a computer  190  with a processor  122  communicating with a memory  146 , the latter holding a program  148  providing an operating system for the warming cabinet  102  and specific executable programs for temperature display and calibration as will be described below. The processor  122  may communicate via various I/O lines  150  which also allow the processor  122  to control or monitor different components of the warming cabinet  102  including a user interface  152  with controls  130  and a visual display  154 , circulating fan  156 , controller  192  for heating elements  126 , temperature sensor(s)  124 , and auxiliary temperature sensor  104 . 
         [0050]    The processor  122  may communicate with the temperature sensor(s)  124 , controller  192  for heating elements  126 , and circulating fan  156  to regulate a temperature of the interior warming chamber  120  as understood in the art. The temperature sensors  124  may be mounted to the walls of the warming cabinet  102  by a bracket or adhesive. The processor  122  may detect an interior temperature of the interior warming chamber  120  via the temperature sensors  124  and turn the heating elements  126  on or off according to a desired warming chamber  120  temperature. 
         [0051]    In one embodiment, the number of temperature sensors  124  may correspond with the number of heating zones within the interior warming chamber  120 . For example, the processor  122  may be configured to independently monitor the temperature from temperature sensors  124  of each heating zone, and then further configured to independently control the heating elements  126  corresponding with each respective heating zone. This may be particularly useful when there is uneven warming within the interior warming chamber  120 , for example, because of uneven loading of items within the cabinet. The heating elements  126  may be arranged as heating pad subassemblies as described in U.S. Pat. No. 8,581,152, assigned to the present applicant, and hereby incorporated by reference. 
         [0052]    The processor may communicate with a circulating fan  156  that may assist to circulate the air within the interior warming chamber  120  and to assist with intake and exhaust of air into and out of the interior warming chamber  120 . The circulation may help to reduce hot or cold spots within the chamber  120 . 
         [0053]    The processor  122  may communicate with a user interface  152  including a visual display  128  and one or more controls  130 . The visual display  128  may be used in conjunction with the controls  130  to set the temperature of the interior warming chamber  120  and to show a set point temperature of the interior warming chamber  120  or of the individual heating elements  126 . The controls  130  may also include a read out button  158  to switch the display from the set point temperature of the interior warming chamber  120  to current temperature conditions (i.e., the temperature of one or more of the heated zones) of the cabinet  102  or a temperature of the auxiliary temperature sensor  104 . 
         [0054]    Referring to  FIGS. 1-3 , the auxiliary temperature device  101  provides a generally rectangular housing  160 . The housing  160  may have vertically extending sidewalls (such as two longer sidewalk  170  connected by two shorter sidewalls  172 ) and enclosed on a top end by a horizontal platform  132  for receipt of the intravenous fluid bag  106  thereon and a rectangular opening  140  to contact a heat collecting plate  164  within the opening  140  of the platform  132 . 
         [0055]    The platform  132  may be a generally rectangular horizontal ceiling, of the housing  160  and may be surrounded by curved concave rails  136  extending upwardly from the platform  132  along the outer edges of the longer sidewalk of the platform  132 . For example, the curved rails  136  may be semi-cylinders. The curved rails  136  generally cradle an intravenous fluid bag  106  situated on the platform  132 . 
         [0056]    The platform  132  also provides a rectangular opening  140  centered within the ceiling to expose the heat collecting plate  164  below the opening  140 . The opening  140  allows the intravenous fluid bag  106  to contact the heat collecting plate  164  disposed within an interior of the housing  160  as further explained below. 
         [0057]    In one embodiment, the platform  132  may be approximately 3 inches long by 4 inches wide or less than than 15 square inches or less than than 12 square inches. The platform  132  may be sized to contact less than 75 percent of the lower surface area of the intravenous fluid bag  106 . In this, respect, the edges of the intravenous fluid bag  106  may extend past the edges of the housing  160  while a center of the bag is substantially supported by the housing  160 . 
         [0058]    In one embodiment, the opening  140  may be approximately 3 inches long by 2 inches wide or greater than 4 square inches or greater than 6 square inches. The opening  140  or exposed area of the heat collecting plate  164  may be sized to contact at least 30% of the lower surface area of the intravenous fluid bag  106 . In this respect, the contact area is large enough to facilitate, conduction from the intravenous fluid bag  106  to the heat collecting plate  164 . 
         [0059]    Referring to  FIG. 3 , disposed within the housing  160 , and centered within the opening  140  of the platform  132  and generally pressed up against the, upper opening  140 , is a heat collecting plate  164  contacting the intravenous fluid bag  106  when the intravenous fluid bag  106  is placed on the platform  132 . The heat collecting plate  164  may be a thin sheet of conductive metal, such as aluminum or copper, which contacts the intravenous fluid bag  106  and conducts the heat from the intravenous fluid bag  106 . The plate may have a minimal gauge thickness (e.g., about 0.01 inches or less than 0.1 inches) to provide low thermal mass (e.g., heat capacity of 003-0.09 J/gm K) to accelerate temperature measurement and has high conductivity. 
         [0060]    An auxiliary temperature sensor  104  may be mounted to the underside of the heat collecting plate  164  and be positioned approximately in the center of the opening  140  to be near a center region of the contact with the intravenous fluid bag  106 . The auxiliary temperature sensor  104  may be mounted to the heat collecting plate  164  using an epoxy resin to provide good heat conductivity between the heat collecting plate  164  and the temperature sensor  104 . 
         [0061]    The temperature sensor  104  detects an approximately average temperature, of the heat collecting plate  164 . It is contemplated that more than one temperature sensor may be used and their temperature readings averaged to approximate a heat collecting plate temperature. Temperature sensor  104  maybe, for example, a thermocouple, a thermistor, a resistive temperature device, or other similar temperature sensing devices. As will be noted below, high linearity is not required because of the calibration system and the ability to process the received temperature signal with the processor  122 . 
         [0062]    It is understood that the flexible material of the intravenous fluid bag  106  permits the intravenous fluid bag  106  to adopt a variety of different volumetric configurations, and the shape of the platform  132  is designed to promote contact of the intravenous fluid bag  106  with the temperature sensor  104 . 
         [0063]    undersurface of the heat collecting plate  164  and the auxiliary temperature sensor  104  is supported by and surrounded by an insulating material  166  reducing the temperature drop between the intravenous fluid bag  106  and the auxiliary temperature sensor  104 . The insulating material  166  may be a Styrofoam or other insulating foam material. 
         [0064]    The insulating material  166  may be supported and sandwiched by a lower panel  168  thereby supporting the heat collecting plate  164 , auxiliary temperature sensor  104 , and insulating material  166  against the force of the intravenous fluid bag  106  thereon. The lower panel  168  may be constructed of a metal sheet defining a floor of the housing  160  held in by the vertical sidewalls  170 ,  172  of the molded plastic housing  160 . The lower panel  168  may be a substantially U-shaped frame or four sided box frame containing upwardly extending sidewalls surrounding a floor with the insulating material  166  carried within or between the sidewalls. 
         [0065]    A channel  167  may extend through the insulating material  166  allowing an electrical connector  174  to extend from the temperature sensor  104  to an exterior of the housing  160 , for example, through a releasable electrical connector or jack  182 . 
         [0066]    The vertical sidewalls  170 ,  172  supporting the horizontal platform  132  of the housing  160  may be shaped so as to provide downwardly extending feet  162  at the lower corners of the housing  160  to lift and support the housing  160  on a table, shelf, basket, or the like. The feet  162  may curved around the lower corners of the housing  160  with carve-outs  161  extending along the lengths of the housings between the feet  162 . 
         [0067]    In one embodiment, when the auxiliary temperature device  101  is supported in the basket  144 , as shown in  FIGS. 1 and 3 , the carve-outs  161  provided between adjacent feet  162  allows the auxiliary temperature device  101  to rest on the spaced wire  194  or metal rods of the baskets  144  without unwanted movement. In particular, the interval between longitudinal rods of the basket or length of the carve-outs  161  may correspond with the space between adjacent feet  162  of the housing  160 . 
         [0068]    Generally the housing  160  and platform  132  will he fabricated from injection molded thermoplastic or the like. 
         [0069]    Referring to  FIGS. 1 and 2 , in operation, the auxiliary temperature device  101  may be connected to the warming cabinet  102  through a releasable electrical connector or jack  182  on the interior or exterior wall of the warming cabinet  102  to communicate with the processor  122  of the warming cabinet  102 . The connection may he made via an electrical connector  174  having first and second modular connectors  176 , similar to telephone plugs, at opposite ends of the connector cord  178 . The modular connectors  176  are insertable into, a mating socket or jack  182 . The first modular connector  176  is insertable into a jack  182  of the cabinet  102  and the second modular connector  176  is insertable into a jack  182  of the auxiliary temperature device  101 , connecting the auxiliary temperature device  101  to the warming cabinet  102 . The connector cord  178  may be coiled, similar to a coiled telephone cord, allowing it to be flexible and extensible from the warming cabinet  102 . 
         [0070]    The jack  182  of the cabinet  102  may be located on an interior wall of the interior warming chamber  120 , such as a lower end of the rear wall  116 , or on an exterior wall of the warming cabinet  102 , or in both positions to allow the auxiliary temperature device  101  to be used in both configurations. The jack  182  of the auxiliary temperature device  101  may be on a sidewall  172 . When the auxiliary temperature device  101  is connected inside the interior heating chamber  120 , the device may be positioned within the chamber  120  such as on shelf  123 , within the basket  144 , or on the floor  110  of the chamber  120 . When the auxiliary temperature device  101  is connected to an exterior wall, the device  101  may be positioned on top of the warming cabinet  102 , a table besides the warming cabinet  102 , or elsewhere near to the warming cabinet  102  during use. 
         [0071]    It is contemplated that the temperature sensor  104 /auxiliary temperature device  101  and processor  122  may also communicate through a wireless communication standard, such as Bluetooth, Wi-Fi, and the like, as understood in the art. 
         [0072]    When the user desires a temperature of the intravenous fluid, bag  106  to be measured, the intravenous fluid bag  106  is placed on the platform  132 , as seen in  FIG. 3 . In particular, the platform  132  is shaped to support the intravenous fluid bag  106  with one lower sheet  184  of the intravenous fluid bag  106  lying in close abutment to the platform  132 . In this way, contact between the intravenous fluid bag  106  and the heat collecting plate  164  may be, substantially maximized and the thermal path between the fluid and the sensor substantially maximized. The edges of the intravenous fluid bag  106  may he cradled by the rails  136  so that a width of the bag lies substantially within the platform  132  while a length of the bag may extend outwardly past an edge of the platform  132 . 
         [0073]    Referring to  FIG. 5 , the processor  122  operates to display a temperature of the interior heating chamber  120  or an, auxiliary temperature device  101 , as provided in the sequence of process steps shown as  196 , when activated by the user. 
         [0074]    As indicated by process block  200 , the processor  122  normally displays a chamber set point temperature (i.e., the temperature at which the user sets or programs the cabinet). 
         [0075]    As shown in process block  201 , the processor  122  may determine whether a read out button  158  is pressed. If the read out button  158  has been pressed once, the processor  122  will receive a temperature signal measured from the chamber temperature sensor  124  indicating a temperature of the interior heating chamber  120  as shown in process block  202 . 
         [0076]    The processor  122  will then display a current state temperature Le., the temperature of one or more of the heated zones) of the cabinet  102  via the temperature sensors  124  of the interior heating chamber  120  and display it on the visual display  128  for a predetermined time period, as shown in process block  203 . For example, the predetermined time may be 20 seconds or 10-20 seconds. Alternatively, the current state temperature may continue to be shown until the user presses a control button  130 , such as read out button  158  once again, to switch the temperature signal input from the temperature sensors  124  back to the chamber set point temperature. 
         [0077]    If the read out button has not been pressed once, the processor  122  may proceed to process block  205 . As shown in process, block  205 , the processor  122  may determine whether read out button  158  has been pressed for a predetermined time period, e.g., for more than three seconds. If so, the processor  122  will proceed to step  206 . 
         [0078]    As indicated by process block  206 , when the user indicates that he or she would like to determine an auxiliary device temperature by pressing the read out button  158  for a predetermined time period, e.g., three or more seconds, the visual display  128  will be zeroed out and will no longer display the chamber set temperature. 
         [0079]    As indicated by process block  208 , the processor  122  will wait a predetermined time period, such as three or three to five seconds, to allow time for heat transfer from the intravenous fluid bag  106  to the heat collecting plate  164  and to accommodate the response time of the auxiliary temperature sensor  104 . As is understood in the art, the program may extrapolate an asymptotic temperature value from a short measurement time. 
         [0080]    As indicated by process block  210 , after the predetermined time has passed, the processor  122  receives a temperature signal measured from the auxiliary temperature sensor  104  indicating a temperature of the intravenous fluid bag  106 . 
         [0081]    As indicated by process block  212 , the temperature of the intravenous fluid bag is displayed on the visual display  128 . The auxiliary temperature sensor  1  temperature may be displayed for a predetermined time period, for example, 20 seconds or 10-20 seconds, before returning to process block  200 . Alternatively, auxiliary temperature may continue to be displayed until the user presses a control button  130 , such as read out button  158 , to switch the temperature signal input from the auxiliary temperature sensor  104  back to chamber set point temperature. 
         [0082]    Referring to  FIG. 6 , optionally as shown in  198 , the auxiliary temperature sensor  104  may be calibrated before use by placing the auxiliary temperature device  101  within an empty warming cabinet  102 . When the auxiliary temperature device  101  is connected to the warming cabinet  102 , the processor  122  will determine whether the user has initiated calibration by pressing the calibrate button of the user interface  152 , as seen in process block  300 . If calibration is initiated by the user, then the process will continue to process block  302 . If calibration is not initiated, then process block  300  is repeated until the calibrate button is pressed. 
         [0083]    As indicated by process block  302 , once calibration is initiated, the process waits a designated amount of time, such as two or one to five minutes, to allow the auxiliary temperature device  101  to reach the interior heating chamber  120  temperature. Again an asymptotic temperature value may be extrapolated. 
         [0084]    As indicated by process block  304 , after the auxiliary temperature device  101  has reached the same temperature as the chamber  120 , then a temperature measurement is taken at the auxiliary temperature sensor  104 . 
         [0085]    As indicated by process block  306 , the processor proceeds to take a temperature measurement of the interior heating chamber  120  at the temperature sensors  124  at the walls of the interior heating chamber  120 . As indicated by process block  308 , the temperature measurement at the auxiliary temperature sensor  104  and at the temperature sensors  124  are compared and a difference is measured. 
         [0086]    As indicated by process block  310 , this difference is subtracted from the reading at the auxiliary temperature sensor  104  to “zero the offset” of the auxiliary temperature sensor  104  and calibrate the temperature for any future temperature readings. 
         [0087]    Certain terminology is used herein for purposes of reference only, and thus is not intended to he limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
         [0088]    When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
         [0089]    References to “a controller” and “a processor” should be understood to include one or more microprocessors that can communicate in, a stand-alone and/or a distributed environment(s), and can thus be configured to communicate via wired or wireless communications with other processors, where such one or more processor can be configured to operate on one or more processor-controlled devices that can be similar or different devices. Furthermore, references to memory, unless otherwise specified, can include one or more processor-readable and accessible memory elements and/or components that can he internal to the processor-controlled device, external to the processor-controlled device, and can be accessed via a wired or wireless network. 
         [0090]    It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the, scope of the following claims. All of the publications described herein, including patents, and non-patent publications, are hereby incorporated herein by reference in their entireties.