Patent Publication Number: US-10791592-B2

Title: Method for operating fans within an appliance

Description:
FIELD OF THE INVENTION 
     The subject matter of the present disclosure relates generally to methods for operating fans within appliances, such as over-the-range (OTR) microwave appliances or vent hood appliances. 
     BACKGROUND OF THE INVENTION 
     Over-the-range microwave appliances are generally mounted above a cooktop of an oven range appliance. Conventionally, cooktop appliances have been largely dependent upon a user monitoring the cooktop during use to determine, e.g., whether a pot of water is boiling or if a spill-over has occurred. There may be times, however, when a user may not be able to monitor the cooktop during use. Accordingly, a sensor may be mounted over the range, e.g., on an over-the-range microwave appliance, to monitor the cooktop positioned beneath the sensor. 
     However, a sensor mounted above the cooktop could become contaminated, e.g., by grease and moisture generated during use of the cooktop, which could impede the ability of the sensor to sense the cooktop. Thus, the sensor should be kept free from contamination by protection of the sensor lens. 
     In addition to providing for heating of food and beverage items, certain over-the-range microwave appliances include an air circulation system. When activated, the circulation system can draw fumes, smoke, grease, and/or steam away from the cooktop of the oven range appliance. Circulation systems generally include a fan for drawing a flow of air into the circulation system and a pathway for the flow of air. Additional fans or other elements may work with the circulation system to enhance the flow of air through the pathway. 
     Accordingly, a method for operating fans within an over-the-range microwave appliance in order to protect sensors of the microwave appliances would be useful. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present subject matter provides a method for operating fans within an appliance. The appliance includes a sensor fan and an exhaust fan. The method includes operating the sensor fan of the appliance when the exhaust fan of the appliance is running. The sensor fan of the appliances urges air over a sensor of the appliance when the sensor fan is operating. Additional aspects and advantages of the invention will be set forth in part in the following description, may be apparent from the description, or may be learned through practice of the invention. 
     In a first exemplary embodiment, a method for operating fans within an appliance is provided. The appliance includes a temperature sensor, a control panel, a control fan positioned adjacent the control panel, a cabinet defining a duct and an exhaust fan configured for drawing air through the duct. The temperature sensor includes a housing positioned at a bottom portion of the cabinet and having a chamber contiguous with the duct of the cabinet. The temperature sensor also includes a sensor fan configured for drawing air out of the duct of the cabinet via the chamber of the housing. The method includes operating the sensor fan at a first power when the exhaust fan is deactivated, activating the exhaust fan, and operating the sensor fan at a second power and activating the control fan after the exhaust fan is activated. The second power output is different than the first power output. The control fan and the sensor fan urge air out of the duct of the cabinet via the chamber of the housing when the sensor fan is operating at the second power and the control fan is activated. 
     In a second exemplary embodiment, a method for operating fans within an appliance is provided. The appliance includes a temperature sensor, a cabinet defining a duct and an exhaust fan configured for drawing air through the duct. The temperature sensor includes a housing positioned at a bottom portion of the cabinet and having a chamber contiguous with the duct of the cabinet. The temperature sensor also includes a sensor fan configured for drawing air out of the duct of the cabinet via the chamber of the housing. The method includes determining whether the exhaust fan is running and activating the sensor fan when the exhaust fan is running or when a temperature measurement from the temperature sensor exceeds a temperature limit and the exhaust fan is not running. The sensor fan urges air out of the duct of the cabinet via the chamber of the housing when the sensor fan is operating. 
     In a third exemplary embodiment, a method for operating fans within an appliance is provided. The appliance includes a temperature sensor, a control panel, a control fan positioned adjacent the control panel, a cabinet defining a duct and an exhaust fan configured for drawing air through the duct. The temperature sensor includes a housing positioned at a bottom portion of the cabinet and having a chamber contiguous with the duct of the cabinet. The temperature sensor also includes a sensor fan configured for drawing air out of the duct of the cabinet via the chamber of the housing. The method includes determining whether the sensor is positioned proximate a heating element of a range in response to receiving a heating element activation signal from the range and operating the sensor fan at a first power when the sensor is positioned proximate the heating element of the range or operating the sensor fan at a second power when the sensor is positioned proximate the heating element of the range and the exhaust fan is running. The second power output is different than the first power output. The sensor fan urges air out of the duct of the cabinet via the chamber of the housing when the sensor fan is operating. 
     In a fourth exemplary embodiment, a method for operating fans within an appliance is provided. The appliance includes a temperature sensor, a control panel, a control fan positioned adjacent the control panel, a cabinet defining a duct and an exhaust fan configured for drawing air through the duct. The temperature sensor includes a housing positioned at a bottom portion of the cabinet and having a chamber contiguous with the duct of the cabinet. The temperature sensor also includes a sensor fan configured for drawing air out of the duct of the cabinet via the chamber of the housing. The method includes operating the sensor fan at a first power in response to receiving a heating element activation signal from a range and operating the sensor fan at a second power when the exhaust fan is running. The second power output is different than the first power output. The sensor fan urges air out of the duct of the cabinet via the chamber of the housing when the sensor fan is operating. 
     These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
         FIG. 1  provides a perspective view of a microwave appliance according to an exemplary embodiment of the present subject matter mounted to a kitchen cabinet above an oven range appliance. 
         FIG. 2  provides a side, section view of the exemplary microwave appliance and oven range appliance of  FIG. 1 . 
         FIG. 3  provides another side, section view of the exemplary microwave appliance and oven range appliance of  FIG. 1 . 
         FIG. 4  provides a section view of a sensor of the exemplary microwave appliance of  FIG. 1 . 
         FIG. 5  illustrates a method of operating fans within an appliance in accordance with a first exemplary embodiment of the present subject matter. 
         FIG. 6  illustrates a method of operating fans within an appliance in accordance with a second exemplary embodiment of the present subject matter. 
         FIG. 7  illustrates a method of operating fans within an appliance in accordance with a third exemplary embodiment of the present subject matter. 
         FIG. 8  illustrates a method of operating fans within an appliance in accordance with a fourth exemplary embodiment of the present subject matter. 
     
    
    
     Use of the same reference numerals in different figures denotes the same or similar features. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
       FIG. 1  provides a perspective view of a microwave appliance  10  according to an exemplary embodiment of the present subject matter mounted to an upper set of kitchen cabinets  14  above an oven range appliance  12 , e.g., along a vertical direction V. Microwave appliance  10  shown in  FIG. 1  is commonly referred to as an over-the-range microwave. Upper set of kitchen cabinets  14  is positioned above a base set of kitchen cabinets  16 , e.g., along the vertical direction V. Base set of kitchen cabinets  16  includes countertops  18  and drawers  17 . Oven range appliance  12  is received within base set of kitchen cabinets  16  below microwave appliance  10 . In particular, a cooking surface  30  of oven range appliance  12  is positioned, e.g., directly, below microwave appliance  10  along the vertical direction V. Microwave appliance  10  can include features such as an air handler or cooling fan  52  ( FIG. 2 ) that can draw cooking vapors and/or smoke away from cooking surface  30  and out of the kitchen containing microwave and oven range appliances  10 ,  12 . 
     Microwave appliance  10  is configured for receipt of food items for cooking. In particular, microwave appliance  10  includes a cabinet or casing  20  and a door  22  that permits selective access to an interior of microwave appliance  10  and casing  20 . Door  22  includes a handle  24  that a user can pull to open door  22  to insert food items into microwave appliance  10 . Microwave appliance  10  also includes controls  26  that permit a user to make selections for cooking of food items, e.g., a duration of a cooking cycle of microwave appliance  10  and/or a power setting for the cooking cycle of microwave appliance  10 . 
     Oven range appliance  12  includes cooking surface  30 . Cooking surface  30  includes heated portions  32  that may be heated by heating elements (not shown), e.g., electrical resistive heating elements, gas burners, induction heating elements, and/or any other suitable heating element or combination of heating elements. Oven range appliance  12  also includes a door  36  that permits access to a heated compartment (not shown) of oven range appliance  12 , e.g., for cooking or baking of food items therein. A control panel  34  of oven range appliance  12  can permit a user to make selections for cooking of food items, e.g., a duration of a cooking cycle of oven range appliance  12  and/or a power setting for the cooking cycle of oven range appliance  12 . 
       FIG. 2  provides a side, section view of microwave appliance  10  and oven range appliance  12 . As illustrated, casing  20  extends between a top portion  42  and a bottom portion  44 , e.g., along the vertical direction V. Thus, top and bottom portions  42  and  44  of casing  20  are spaced apart from each other, e.g., along the vertical direction V. Casing  20  defines a cooking chamber  40  configured for receipt of food items for cooking. Door  22  of microwave appliance  10  permits selective access to cooking chamber  40  of casing  20 . In particular, door  22  of microwave appliance  10  is selectively adjustable between an open position (not shown) and a closed position ( FIGS. 1 and 2 ). In the closed position, door  22  of microwave appliance  10  hinders access to cooking chamber  40  of casing  20 . Conversely, door  22  of microwave appliance  10  permits access to cooking chamber  40  of casing  20  in the open position. A user can pull on handle  24  of door  22  of microwave appliance  10  in order to shift door  22  from the closed position shown in  FIG. 2  to the open position. 
     Casing  20  also defines an air conduit or pathway  46 . Pathway  46  has an inlet  48  and an outlet  50 . Pathway  46  extends between inlet  48  and outlet  50 . Inlet  48  of pathway  46  is positioned at or adjacent bottom portion  44  of casing  20 , e.g., such that inlet  48  of pathway  46  faces cooking surface  30  of oven range appliance  12 . Conversely, outlet  50  of pathway  46  is positioned at or adjacent top portion  42  of casing  20 , e.g., such that outlet  50  of pathway  46  faces away from cooking surface  30  of oven range appliance  12 . In certain exemplary embodiments, outlet  50  may face in the opposite direction, although preferably not toward cooking surface  30 . Thus, inlet  48  and outlet  50  of pathway  46  are spaced apart from each other, e.g., along the vertical direction V. 
     Microwave appliance  10  also includes a vent fan  52 , such as an axial fan or a radial fan. Vent fan  52  is positioned within or adjacent pathway  46 . Vent fan  52  draws or urges a flow of air (shown with arrows F) through pathway  46  when vent fan  52  is in an activated state. Conversely, cooling fan  52  does not draw or urge flow of air F through pathway  46  when cooling fan  52  is in a deactivated state. When cooling fan  52  is in the activated state, flow of air F enters pathway  46  at or through inlet  48  of pathway  46 . Flow of air F is directed through pathway  46  to outlet  50 , and flow of air F can exit pathway  46  at outlet  50  of pathway  46 . In such a manner, vent fan  52  may draw cooking fumes from oven range appliance  10  through pathway  46 , e.g., such that microwave appliance  10  acts as a hood for oven range appliance  12 , as will be understood by those skilled in the art. 
     As may be seen in  FIG. 2 , microwave appliance  10  may further include a controller  56 . Operation of microwave appliance  10  may be regulated by controller  56 . Controller  56  is operatively coupled or in communication with various components of microwave appliance  10 , including controls  26 . In response to user manipulation of controls  26 , controller  56  operates the various components of microwave appliance  10  to execute selected cycles and features. Controller  56  may also be in operative communication with cooling fan  52 . Thus, controller  56  can selectively adjust cooling fan  52  between the activated and deactivated states to regulate the flow of air F through pathway  46 . 
     Controller  56  may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with a cleaning cycle. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller  56  may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software. Controls  26  and other components of microwave appliance  10  may be in communication with controller  56  via one or more signal lines or shared communication busses. 
     Microwave appliance  10  and oven range appliance  12  may be in signal communication with each other, e.g., via a network. Thus, microwave appliance  10  and oven range appliance  12  may each include suitable components for interfacing with one more networks. For example, network interfaces of microwave appliance  10  and oven range appliance  12  may include transmitters, receivers, ports, controllers, antennas, or other suitable components for interfacing with an associated network, e.g., wired or wireless. The network between microwave appliance  10  and oven range appliance  12  may be any type of communications network, such as a local area network (e.g. intranet), wide area network (e.g. Internet), or some combination thereof. In general, communication between microwave appliance  10  and oven range appliance  12  may be carried via associated network interfaces using any type of connection, using a variety of communication protocols (e.g. TCP/IP, HTTP), encodings or formats (e.g. HTML, XML), and/or protection schemes (e.g. VPN, secure HTTP, SSL). 
     Additionally, microwave appliance  10  may support a sensor system  60  such that cooking surface  30  is positioned beneath sensor system  60 . Sensor system  60  includes a sensor  62  for monitoring cooking surface  30  and any cooking utensils containing food items for cooking, such as, e.g., cooking utensil  28 , on cooking surface  30 . More particularly, sensor  62  is configured, e.g., to detect whether a cooking utensil is present on cooking surface  30  and, if so, to provide a signal indicative of the same to controller  56 . Sensor  62  may also be equipped with other features such as, e.g., the ability to determine (and provide a signal indicative of) the temperature of the cooktop, a utensil placed on the cooktop, and/or food present on the cooktop. Sensor  62  may be an optical sensor or any other sensor suitable for monitoring cooking surface  30 . Further, sensor  62  may be in operative communication with controller  56 , which may output an indicator signal to, e.g., a controls display  58  of microwave appliance  10  or another suitable source to alert a user to the status of cooking surface  30  or food items within cooking utensils  28  on cooking surface  30 . As shown in  FIG. 2 , sensor system  60  may be in fluid communication with pathway  46 . More particularly, air flowing through pathway  46  may also cause air to flow through sensor system  60 , as will be further described. 
     As an example, in the exemplary embodiment illustrated in  FIG. 3 , microwave appliance  10  includes a control fan  51  that creates a flow of air F through a controls duct or compartment  57 , in which controller  56  is positioned. More particularly, control fan  51  draws air through inlet  48  and past controller  56  and a magnetron  120  and power supply  122  within compartment  57 . Additionally, an exhaust fan  53  draws or urges air flow F to exit compartment  57  through outlet  50 . Sensor system  60  is in fluid communication with compartment  57  such that air flowing through compartment  57  also causes air to flow through sensor system  60  as will be described. Other configurations of microwave appliance  10  and sensor system  60  may also be used, or sensor system  60  could be supported by any other suitable appliance or surface. In certain exemplary embodiments, cooling fan  52  and exhaust fan  53  may be a common or single fan. 
     It should be understood that sensor system  60  may be used in or with any other suitable appliance in alternative embodiments. Thus, while described in the context of microwave appliance  10 , it should be understood that sensor system  60  may be used in other appliances in alternative exemplary embodiments. For example, sensor system  60  may be mounted on or within a vent hood appliance over oven range appliance  12 . The vent hood appliance may include the same or similar fans as described above for microwave appliance  10 . 
       FIG. 4  provides a section view of sensor system  60 . As an example, sensor system  60  may be constructed in the same or a similar manner to the sensor system described in U.S. Patent Publication No. 2015/0260193 of James Lee Armstrong et al. entitled “Sensing System for a Cooktop Appliance with Airflow Protected Sensor” and/or U.S. Patent Publication No. 2015/0257591 of James Lee Armstrong et al. also entitled “Sensing System for a Cooktop Appliance with Airflow Protected Sensor,” both of which are hereby incorporated by reference in their entirety for all purposes. 
     As shown in  FIG. 4 , sensor  62  of sensor system  60  is contained within an inner housing  68  that is positioned within an outer housing  64 . Outer housing  64  defines a chamber  66  that is in fluid communication with compartment  57  (and/or pathway  46 ). Inner housing  68  is positioned within chamber  66  such that inner housing  68  and outer housing  64  define a channel  70  for a flow of air F. Moreover, inner housing  68  defines a sensor aperture  76 , and a sensing end  78  of sensor  62  is positioned at sensor aperture  76 . Sensor aperture  76  may be open or may have a protective covering such as, e.g., a glass lens. 
     Channel  70  has a channel inlet  72  positioned downstream of control fan  51  and in fluid communication with chamber  66  to receive a flow of air F from compartment  57 . Further, channel  70  has a channel outlet  74  from which the flow of air F flows past sensing end  78  of sensor  62 . The flow of air F acts to protect sensing end  78  by blowing away, e.g., moisture, grease, or other contaminants generated during use of the cooking surface  30  that might otherwise block or impede the proper operation of sensor  62 . 
     A sensor fan  80  is positioned within chamber  66  of outer housing  68  adjacent channel inlet  72 . Sensor fan  80  may be used in addition to control fan  51  and/or exhaust fan  53  to create air flow F. Sensor fan  80  may also be used instead of control fan  51  and/or exhaust fan  53  to create air flow F. Thus, sensor fan  80  is in operative communication with controller  56  and is configured to urge the flow of air F through channel  70  and past sensing end  78  of sensor  62  to keep sensing end  78  free from contamination. Control fan  51  and/or exhaust fan  53  may assist sensor fan  80  with urging the flow of air F through channel  70  and past sensing end  78  of sensor  62 . 
       FIG. 5  illustrates a method  500  of operating fans within an appliance in accordance with a first exemplary embodiment of the present subject matter. Method  500  may be used in or with any suitable appliance, such as a microwave appliance or a vent hood appliance. For example, method  500  may be used in or with microwave appliance  10 , e.g., to regulate or control at least one of control fan  51 , cooling fan  52 , exhaust fan  53  and sensor fan  80 . Controller  56  of microwave appliance  10  may be configured or programmed to implement method  500 . Thus, method  500  is discussed in greater detail below in the context of microwave appliance  10 . Method  500  may assist with limiting or preventing ambient air about microwave appliance  10  from flowing into microwave appliance  10  via sensor system  60 , e.g., through chamber  66  of outer housing  68 . In such a manner, accumulation of particles and other debris on sensor  62  from ambient air about microwave appliance  10  may be reduced or limited and performance of sensor system  60  may be improved. 
     At step  510 , controller  56  receives a sensor activation signal from oven range appliance  12  or from controls  26  of microwave appliance  10 . As an example, a user of oven range appliance  12  may utilize control panel  34  to activate one of heated portions  32  of oven range appliance  12 . In response to the user input at control panel  34  and/or the activation of one of heated portions  32 , oven range appliance  12  may transmit the sensor activation signal to microwave appliance  10 . Microwave appliance  10  and oven range appliance  12  may communicate with each other via a network in order to transmit the sensor activation signal from oven range appliance  12  to microwave appliance  10  at step  510 . 
     At step  520 , controller  56  operates sensor fan  80  at a first power. When sensor fan  80  is operating at the first power, sensor fan  80  may draw air through chamber  66  over sensor  62  in order to limit or prevent particle accumulation on sensor  62 . Thus, the flow of air F through chamber  66  out of sensor  62  may assist with shielding sensor  62  and keeping sensor  62  clean. Exhaust fan  53  may be deactivated at step  520 . 
     At step  530 , controller  56  determines whether exhaust fan  53  is operating, turned on or activated. Thus, e.g., a user of microwave appliance  10  may operate microwave appliance  10  such that exhaust fan  53  activates between steps  520  and  530 . If exhaust fan  53  is not operating at step  530 , method  500  continues to step  560 . Conversely, controller  56  increases a power supplied to sensor fan  80  at step  540  if exhaust fan  53  is operating at step  530 . In particular, controller  56  may increases the power supplied to sensor fan  80  from the first power to a second power at step  540 , with the second power being different (e.g., greater) than the first power. It should be understood that the first and second powers may be equal in certain exemplary embodiments, e.g., when the first and second powers are both high powers. 
     Exhaust fan  53  may be larger than sensor fan  80 , and exhaust fan  53  may urge or draw air to exhaust fan  53  fan via any air pathway, such as chamber  66  of sensor  60 , during operation of exhaust fan  53 . Thus, with sensor fan  80  operating at a first power, exhaust fan  53  may overpower sensor fan  80  and draw ambient air about microwave appliance  10  into sensor system  60  via chamber  66  of outer housing  68 . By increasing the power supplied to sensor fan  80  from the first power to the second power when exhaust fan  53  is operating at step  530 , sensor fan  80  may continue to draw air through chamber  66  over sensor  62  in order to limit or prevent particle accumulation on sensor  62 , and the flow of air F through chamber  66  out of sensor  62  may continue to assist with shielding sensor  62  and keeping sensor  62  clean when sensor fan  80  is operating at the second power by counteracting the draw of exhaust fan  53 . 
     At step  550 , controller  56  may also activate, turn on or operate control fan  51 . When activated control fan  51  may assist sensor fan  80  with drawing air through chamber  66  over sensor  62  in order to limit or prevent particle accumulation on sensor  62 . In particular, as shown in  FIG. 3 , control fan  51  may be disposed upstream of exhaust fan  53  and sensor fan  80  relative to the flow of air F. Thus, by activating control fan  51  at step  550 , control fan  51  may assist sensor fan  80  with maintaining the flow of air F through chamber  66  out of sensor  62  when exhaust fan  53  is operating. 
     At step  560 , controller  56  receives a sensor deactivation signal from oven range appliance  12 . As an example, a user of oven range appliance  12  may utilize control panel  34  to deactivate heated portions  32  of oven range appliance  12 . In response to the user input at control panel  34  and/or the deactivation of one of heated portions  32 , oven range appliance  12  may transmit the sensor deactivation signal to microwave appliance  10 . At step  570 , controller  56  may deactivate control fan  51 , cooling fan  52 , exhaust fan  53  and/or sensor fan  80  after the sensor deactivation signal is received at step  570 . Thus, once cooking operations on oven range appliance  12  are complete, and smoke/fumes from oven range appliance  12  are diffused, controller  56  may deactivate control fan  51 , cooling fan  52 , exhaust fan  53  and/or sensor fan  80 . In such a manner, method  500  may selectively operate control fan  51 , exhaust fan  53  and/or sensor fan  80  in order to generate the flow of air F over sensor  62  as needed, e.g., during operation of oven range appliance  12 . 
       FIG. 6  illustrates a method  600  of operating fans within a microwave appliance in accordance with a second exemplary embodiment of the present subject matter. Method  600  may be used in or with any suitable appliance, such as a microwave appliance or a vent hood appliance. For example, method  600  may be used in or with microwave appliance  10 , e.g., to regulate or control at least one of control fan  51 , cooling fan  52 , exhaust fan  53  and sensor fan  80 . Controller  56  of microwave appliance  10  may be configured or programmed to implement method  600 . Thus, method  600  is discussed in greater detail below in the context of microwave appliance  10 . Method  600  may assist with limiting or preventing ambient air about microwave appliance  10  from flowing into microwave appliance  10  via sensor system  60 , e.g., through chamber  66  of outer housing  68 . In such a manner, accumulation of particles and other debris on sensor  62  from ambient air about microwave appliance  10  may be reduced or limited and performance of sensor system  60  may be improved. 
     At step  610 , controller  56  determines whether exhaust fan  53  is operating, turned on or activated. Thus, e.g., a user of microwave appliance  10  may activate microwave appliance  10  such that exhaust fan  53  turns on prior to step  610 . If exhaust fan  53  is operating at step  610 , method  600  continues to step  640 . Conversely, controller  56  utilizes sensor  62  to measure a temperature, e.g., of a cooking utensil on one of heated portions  32  or food within the cooking utensil, at step  620  if exhaust fan  53  is not operating at step  610 . As an example, controller  56  may receive a signal from sensor  62  that corresponds to a temperature measurement at step  620 . 
     At step  630 , controller  56  determines whether the temperature measurement from sensor  62  exceeds a temperature limit. If the temperature measurement from sensor  62  exceeds the temperature limit at step  630 , method  600  continues to step  640 . At step  640 , controller  56  operates sensor fan  80 . When oven range appliance  12  is operating and cooking food within a cooking utensil on one of heated portions  32 , the food may emit smoke, fumes, vapors, etc., and such fluids may rise towards microwave appliance  10 . In particular, such fluids may flow towards sensor  62  during operation of oven range appliance  12 . However, when sensor fan  80  is operating at step  640 , sensor fan  80  may draw air through chamber  66  over sensor  62  in order to limit or prevent particle accumulation on sensor  62 . Thus, the flow of air F through chamber  66  out of sensor  62  may assist with shielding sensor  62  and keeping sensor  62  clean. Thus, by monitoring temperature measurements from sensor  62  at steps  620 ,  630 , controller  56  may activate sensor fan  80  at step  640  to provide the flow of air F over sensor  62  and keep sensor  62  clean during operation of oven range appliance  12 . Similar, controller  56  may activate sensor fan  80  at step  640  to provide the flow of air F over sensor  62  and keep sensor  62  clean during operation of oven range appliance if exhaust fan  53  is operating at step  610 , e.g., in order to overcome the draw of exhaust fan  53 , as discussed above. 
     If the temperature measurement from sensor  62  does not exceed the temperature limit at step  630 , method  600  continues to step  650 . At step  650 , controller  56  deactivates sensor fan  80 . Thus, when temperature measurements from sensor  62  drop below the temperature limit, controller  56  may deactivate sensor fan  80  at step  650  in order to terminate the flow of air F over sensor  62 , e.g., because the flow of air F is no longer needed. In such a manner, method  600  may selectively operate sensor fan  80  in order to generate the flow of air F over sensor  62  as needed, e.g., during operation of oven range appliance  12 . 
       FIG. 7  illustrates a method  700  of operating fans within a microwave appliance in accordance with a third exemplary embodiment of the present subject matter. Method  700  may be used in or with any suitable appliance, such as a microwave appliance or a vent hood appliance. For example, method  700  may be used in or with microwave appliance  10 , e.g., to regulate or control at least one of control fan  51 , cooling fan  52 , exhaust fan  53  and sensor fan  80 . Controller  56  of microwave appliance  10  may be configured or programmed to implement method  700 . Thus, method  700  is discussed in greater detail below in the context of microwave appliance  10 . Method  700  may assist with limiting or preventing ambient air about microwave appliance  10  from flowing into microwave appliance  10  via sensor system  60 , e.g., through chamber  66  of outer housing  68 . In such a manner, accumulation of particles and other debris on sensor  62  from ambient air about microwave appliance  10  may be reduced or limited and performance of sensor system  60  may be improved. 
     At step  710 , controller  56  receives a sensor activation signal from oven range appliance  12 . As an example, a user of oven range appliance  12  may utilize control panel  34  to activate one of heated portions  32  of oven range appliance  12 . In response to the user input at control panel  34  and/or the activation of one of heated portions  32 , oven range appliance  12  may transmit the sensor activation signal to microwave appliance  10 . Microwave appliance  10  and oven range appliance  12  may communicate with each other via a network in order to transmit the sensor activation signal from oven range appliance  12  to microwave appliance  10  at step  710 . 
     At step  720 , controller  56  operates sensor fan  80  at a first power. When sensor fan  80  is operating at the first power, sensor fan  80  may draw air through chamber  66  over sensor  62  in order to limit or prevent particle accumulation on sensor  62 . Thus, the flow of air F through chamber  66  out of sensor  62  may assist with shielding sensor  62  and keeping sensor  62  clean. Exhaust fan  53  may be deactivated at step  720 . 
     At step  730 , controller  56  determines whether exhaust fan  53  is operating, turned on or activated. Thus, e.g., a user of microwave appliance  10  may operate microwave appliance  10  such that exhaust fan  53  activates between steps  720  and  730 . If exhaust fan  53  is not operating at step  730 , method  700  continues to step  760 . Conversely, controller  56  increases a power supplied to sensor fan  80  at step  740  if exhaust fan  53  is operating at step  730 . In particular, controller  56  may increases the power supplied to sensor fan  80  from the first power to a second power at step  740 , with the second power being different (e.g., greater) than the first power. It should be understood that the first and second powers may be equal in certain exemplary embodiments, e.g., when the first and second powers are both high powers. 
     Exhaust fan  53  may be larger than sensor fan  80 , and exhaust fan  53  may urge or draw air to exhaust fan  53  fan via any air pathway, such as chamber  66  of sensor  60 , during operation of exhaust fan  53 . Thus, with sensor fan  80  operating at a first power, exhaust fan  53  may overpower sensor fan  80  and draw ambient air about microwave appliance  10  into sensor system  60  via chamber  66  of outer housing  68 . By increasing the power supplied to sensor fan  80  from the first power to the second power when exhaust fan  53  is operating at step  730 , sensor fan  80  may continue to draw air through chamber  66  over sensor  62  in order to limit or prevent particle accumulation on sensor  62 , and the flow of air F through chamber  66  out of sensor  62  may continue to assist with shielding sensor  62  and keeping sensor  62  clean when sensor fan  80  is operating at the second power by counteracting the draw of exhaust fan  53 . 
     At step  750 , controller  56  may also activate, turn on or operate control fan  51 . When activated control fan  51  may assist sensor fan  80  with drawing air through chamber  66  over sensor  62  in order to limit or prevent particle accumulation on sensor  62 . In particular, as shown in  FIG. 3 , control fan  51  may be disposed upstream of exhaust fan  53  and sensor fan  80  relative to the flow of air F. Thus, by activating control fan  51  at step  750 , control fan  51  may assist sensor fan  80  with maintaining the flow of air F through chamber  66  out of sensor  62  when exhaust fan  53  is operating. 
     At step  760 , controller  56  receives a sensor deactivation signal from oven range appliance  12 . As an example, a user of oven range appliance  12  may utilize control panel  34  to deactivate heated portions  32  of oven range appliance  12 . In response to the user input at control panel  34  and/or the deactivation of one of heated portions  32 , oven range appliance  12  may transmit the sensor deactivation signal to microwave appliance  10 . 
     At step  770 , controller  56  utilizes sensor  62  to measure a temperature, e.g., of a cooking utensil on one of heated portions  32  or food within the cooking utensil. As an example, controller  56  may receive a signal from sensor  62  that corresponds to a temperature measurement at step  770 . Thus, after receiving the sensor deactivation signal from oven range appliance  12 , controller  56  may start monitoring temperature measurements from sensor  62 . 
     At step  780 , controller  56  determines whether the temperature measurement from sensor  62  exceeds a temperature limit. If the temperature measurement from sensor  62  does not exceed the temperature limit at step  770 , controller  56  continues to monitor temperature measurements from sensor  62 . While monitoring temperature measurements from sensor  62 , sensor fan  80  and/or control fan  51  may continue to operate. Even when oven range appliance  12  is deactivated, the food on oven range appliance  12  may emit smoke, fumes, vapors, etc., and such fluids may rise towards microwave appliance  10 , e.g., due to the heat remaining in heated portions  32  or cooking utensils. In particular, such fluids may flow towards sensor  62  during operation of oven range appliance  12 . However, when sensor fan  80  and/or control fan  51  are operating, sensor fan  80  and/or control fan  51  may draw air through chamber  66  over sensor  62  in order to limit or prevent particle accumulation on sensor  62 . Thus, the flow of air F through chamber  66  out of sensor  62  may assist with shielding sensor  62  and keeping sensor  62  clean. By monitoring temperature measurements from sensor  62  at steps  770 ,  780 , controller  56  may keep sensor fan  80  and/or control fan  51  activated until oven range appliance  12  cools. 
     Method  700  continues to step  790  if the temperature measurement from sensor  62  does not exceed the temperature limit at step  770 . At step  790 , controller  56  deactivates sensor fan  80 . Thus, when temperature measurements from sensor  62  drop below the temperature limit, controller  56  may deactivate sensor fan  80  at step  650  in order to terminate the flow of air F over sensor  62 , e.g., because the flow of air F is no longer needed. In such a manner, once cooking operations on oven range appliance  12  are complete, and smoke/fumes from oven range appliance  12  are diffused, controller  56  may deactivate control fan  51 , cooling fan  52 , exhaust fan  53  and/or sensor fan  80 . In such a manner, method  700  may selectively operate control fan  51 , exhaust fan  53  and/or sensor fan  80  in order to generate the flow of air F over sensor  62  as needed, e.g., during operation of oven range appliance  12 . 
       FIG. 8  illustrates a method  800  of operating fans within a microwave appliance in accordance with a fourth exemplary embodiment of the present subject matter. Method  800  may be used in or with any suitable appliance, such as a microwave appliance or a vent hood appliance. For example, method  800  may be used in or with microwave appliance  10 , e.g., to regulate or control at least one of control fan  51 , cooling fan  52 , exhaust fan  53  and sensor fan  80 . In particular, method  800  may supplement method  700 , as discussed in greater detail below. Controller  56  of microwave appliance  10  may be configured or programmed to implement method  800 . Thus, method  800  is discussed in greater detail below in the context of microwave appliance  10 . Method  800  may assist method  700  with limiting or preventing ambient air about microwave appliance  10  from flowing into microwave appliance  10  via sensor system  60 , e.g., through chamber  66  of outer housing  68 . In such a manner, accumulation of particles and other debris on sensor  62  from ambient air about microwave appliance  10  may be reduced or limited and performance of sensor system  60  may be improved. 
     Steps  810 ,  820 ,  830  and  840  may be performed during method  700 , as discussed in greater detail below. In particular, step  810  may correspond to step  710  from method  700 . At step  820 , controller  56  determines whether sensor  62  is proximate the heated portion  32  of oven range appliance  12  activated at step  810 . For example, controller  56  may determine whether sensor  62  is positioned directly above the heated portion  32  of oven range appliance  12  activated at step  810 . If sensor  62  is proximate the heated portion  32  of oven range appliance  12  activated at step  810 , method  800  proceeds to step  830  that corresponds to step  720  of method  700 . Conversely, method  700  proceeds to step  840  if sensor  62  is not proximate the heated portion  32  of oven range appliance  12  activated at step  810 . In such a manner, method  800  may avoid operating sensor fan  80  at the first power when sensor  62  is not proximate the heated portion  32  of oven range appliance  12  activated at step  810 . From step  840 , method  800  may proceed to step  740  or step  760  as described above for method  700 . 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.