Patent Application
20180259189
The present subject matter relates generally to cooktop appliances, and more particularly to electric cooktop appliances.
Cooking appliances, such as, e.g., cooktops or ranges (also known as hobs or stoves), generally include one or more heated portions for heating or cooking food items within a cooking utensil placed on the heated portion. The heated portions utilize one or more heating sources to output heat, which is transferred to the cooking utensil and thereby to any food item or items within the cooking utensil. Typically, a controller or other control mechanism, such as an electromechanical switch, regulates the heat output of the heating source selected by a user of the cooking appliance, e.g., by turning a knob or interacting with a touch-sensitive control panel. For example, the control mechanism may cycle the heating source between an activated or on state and a substantially deactivated or off state such that the average heat output of the heating source corresponds to the user-selected heat output level.
The control mechanism can utilize a temperature sensor to help control the heat output in order to regulate or otherwise limit the cooking utensil from reaching an undesired temperature level. The transfer of heat to the cooking utensil and/or food items may cause the food items or cooking utensil to overheat or otherwise cause unwanted and/or unsafe conditions on the cooktop. Although conventional cooking appliances may include a safety feature for estimating temperature at the cooking utensil, such systems are often unable to provide a suitable evaluation of the current conditions near the burner or at a cooking utensil disposed thereon. Moreover, conventional appliances may be unable to quickly evaluate the current or “live” conditions near the burner. Undesirable swings in temperature may occur at the heating source and/or cooking utensil before conventional appliances are able to detect that an excessive or deficient temperature has been reached. For example, excessive temperatures may cause some food items to be burnt or overcooked. As another example, deficient temperatures may cause boiling water to lose water movement.
Accordingly, a cooktop appliance having a system for accurately detecting temperature conditions near a heat source would be desirable. More particularly, it may be desirable for a cooktop appliance to have a system that addresses one or more of the conditions discussed above.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one aspect of the present disclosure, a cooktop appliance is provided. The cooktop appliance may include a panel, an electric heating element, an infinite switch, and a temperature switch. The electric heating element may be positioned at the panel and include a first terminal and a second terminal. The infinite switch may be electrically coupled to the electric heating element to control power thereto. The infinite switch may include a primary voltage path and an auxiliary voltage path independent from the primary voltage path. The temperature switch disposed in thermal communication with the electric heating element, the temperature switch being in alternate communication with the primary voltage path below a predetermined threshold temperature and with the auxiliary voltage path at or above the predetermined threshold temperature.
In another aspect of the present disclosure, a cooktop appliance is provided. The cooktop appliance may include a panel, an electric heating element, a bimetallic temperature switch, and an infinite switch. The electric heating element may be positioned at the panel and extend between a first terminal and a second terminal. A bimetallic temperature switch may be positioned in thermal communication with the electric heating element. The bimetallic temperature switch may include a pole terminal alternately connected to a first throw terminal and a second throw terminal according to a temperature at the bimetallic temperature switch. The pole terminal may be electrically coupled in series with the second terminal. The infinite switch may be electrically coupled to the bimetallic temperature switch to control power at the electric heating element.
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.
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.
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.
Generally, the present disclosure provides a cooktop appliance that includes at least one heating assembly. The heating assembly may have one or more electric heating elements and drip pan that is positioned below the electric heating element(s). A temperature switch may detect the heat transmitted from the electric heating element(s). The temperature switch may be connected to an infinite switch that has two separate duty cycle paths. When the temperature switch detects a certain temperature, it may connect to one duty cycle path. When the certain temperature is not detected, the temperature switch may connect to the other duty cycle path. For instance, if and/or when the temperature falls by a sufficient amount, the temperature switch may connect the electric heating element to the other of the two duty cycle paths.
Turning now to the figures,
Panel 20 of cooktop appliance 10 includes one or more heating assemblies 22 having at least one heat zone 23. Panel 20 may be constructed of any suitable material, e.g., a ceramic, enameled steel, or stainless steel. As shown in
Example embodiments include a user interface 16 having one or more control inputs 18 permits a user to make selections for cooking of food items using heating assemblies 22 and/or the cooking chamber. As an example, a user may manipulate one or more control inputs 18 to select, e.g., a power or heat output setting for each heating assembly 22. The selected heat output setting of heating assembly 22 affects the heat transferred to cooking utensil 12 positioned on heating assembly 22. Although shown on a backsplash or back panel of cooktop appliance 10, user interface 16 may be positioned in any suitable location, e.g., along a front edge of the appliance 10. Control inputs 18 may include one or more buttons, knobs, or touch screens, as well as combinations thereof.
Some embodiments further include a controller 32 operably connected (e.g., electrically coupled) to user interface 16 and/or control inputs 18. Generally, operation of cooking appliance 10, including heating assemblies 22, may be controlled by controller 32. In some embodiments, controller 32 is a processing device and may include a microprocessor or other device that is in operable communication with components of appliance 10, such as heating assembly 22. Controller 32 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 selected heating level, operation, or cooking cycle. The memory may represent random access memory such as DRAM, and/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 32 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.
Control inputs 18 and other components of cooking appliance 10 may be in communication with (e.g., electrically coupled to) controller 32 via one or more signal lines or shared communication busses. Moreover, heating assembly 22 may be operably connected to controller 32, e.g., at one or more respective terminal pairs.
As will be described in further detail below, operation of heating assembly 22 may be regulated such that the temperature or heat output of heating assembly 22 corresponds to a temperate or heat output selected by a user of cooktop appliance 10. For example, one or more electric heating elements 21 (
As illustrated in
A first terminal 46 and a second terminal 48 are provided for heating element 21. An electrical current may be transmitted to a resistive coil 24 at the terminals 46, 48. When a voltage differential is applied across first and second terminal 48s 46, 48 of resistive coil 24, a temperature of electric heating element 21 increases. Resistive coil 24 may be a CALROD® coil in certain example embodiments.
In some embodiments, such as those illustrated at
First voltage path 112 is configured for operating at a first voltage, L1, with respect to ground. Thus, first electrical conduit 42 may be coupled or connected to a first voltage source operating at the first voltage L1 with respect to ground. The secondary voltage paths 114, 116 are formed in parallel and configured for operating at a second voltage, L2, with respect to ground. Thus, secondary voltage paths 114, 116 may be coupled or connected to a second voltage source operating at the second voltage L2 with respect to ground.
The first voltage L1 and the second voltage L2 have opposite polarities. In addition, a magnitude of the first voltage L1 with respect to ground may be about equal to a magnitude the second voltage L2 with respect to ground. As used herein, the term “about” corresponds to within ten volts of a stated voltage when used in the context of voltage. As an example, the magnitude of the first and second voltages L1, L2 may be about one hundred and twenty volts with respect to ground. Thus, first voltage path 112 may be coupled to one phase of a two-hundred and forty volt household electrical supply, and secondary voltage paths 114, 116 may be coupled to the second phase of the two-hundred and forty volt household electrical supply.
In some embodiments, the secondary paths include a primary voltage path 114 and an auxiliary voltage path 116. As shown, primary voltage path 114 and auxiliary voltage path 116 are generally independent of each other. For instance, primary voltage path 114 and auxiliary voltage path 116 may be assembled in parallel to each other. During use, each of primary voltage path 114 and auxiliary voltage path 116 may thus alternately operate at second voltage L2.
In further embodiments, primary voltage path 114 and auxiliary voltage path 116 each provide a unique duty cycle. For instance, primary voltage path 114 may be a high duty cycle path while auxiliary voltage path 116 is a low duty cycle path. In other words, primary voltage path 114 may permit a first power output over a duty cycle and auxiliary voltage path 116 may permit a second power output over another duty cycle.
In certain embodiments, each power output is a variable output. In other words, each of first power output and second power output provide a separate scale and/or maximum power output value. Nonetheless, it is understood that the second power output is generally less than the first power output. For instance, in some embodiments, the first power output has a 100% maximum output value while the second power output has a 50% maximum output value. In additional or alternative embodiments, the power output scale of the first power output spans 0% to 100% of a maximum output while the power output scale of the second power output spans 0% to 50% of a maximum output. During use, the duty cycle of the first power output activates or turns on heating element 21 for a first fraction or portion of the duty cycle and deactivates or turns off heating element 21 for the remainder of the duty cycle. The duty cycle of the second power output activates or turn on heating element 21 for a second fraction or portion of the duty cycle (e.g., that is less than that of the first duty cycle) and deactivates or turns off heating element 21 for the remainder of the duty cycle. Thus, the general, average, and/or median operating temperature of the first power output will be greater than the general, average, and/or median operating temperature of the second power output.
As shown in
In some embodiments, a rotatable cam 118 variably biases one or both of bimetal strips 124, 126 towards a respective conductive terminal 134B, as shown in
Returning to
Temperature switch 36 may generally be operable to alternate a connection between voltage paths 114, 116 and electric heating element 21 at a predetermined temperature. In some such embodiments, temperature switch 36 includes a pole terminal 128, as well as a first throw terminal 130 and a second throw terminal 132. For instance, temperature switch 36 may be provided as a single pole double throw switch. As shown, temperature switch 36 is electrically coupled to infinite switch 110. In specific embodiments, the first throw terminal 130 of temperature switch 36 is electrically coupled to primary voltage path 114, and second throw terminal 132 of temperature switch 36 is electrically coupled to auxiliary voltage path 116. According to the temperature, pole terminal 128 may actuate between first throw terminal 130 and second throw terminal 132. Thus, some embodiments of temperature switch 36 are in alternate communication with the primary voltage path 114 and the auxiliary voltage path 116.
Temperature switch 36 is generally provided as a temperature-responsive member. When assembled, temperature switch 36 may configured for actuating from a first, e.g., high duty cycle, state (
Optional embodiments of temperature switch 36 are provided as a bimetallic switch, e.g., as a single pole double throw bimetallic switch. A bimetallic member within temperature switch 36 may thus actuate or adjust from the first state to the second state when the temperature of temperature switch 36 exceeds the threshold temperature. The materials of temperature switch (e.g., the bimetallic member) may be selected to such that temperature switch 36 triggers or trips between first throw terminal 130 and second throw terminal 132 at the threshold temperature.
It is understood that the threshold temperature may be any suitable temperature. For example, the threshold temperature may be about three hundred and twenty-five degrees Celsius. As another example, the threshold temperature may be between about ninety degrees Celsius and about four hundred degrees Celsius. As used herein, the term “about” corresponds to within twenty-five degrees of a stated temperature when used in the context of temperature. The threshold temperature may be may be selected such that the threshold temperature accounts for a position of temperature switch 36 relative to heating assembly 22 and/or cooking utensil 12 (
A first electrical conduit 42 is coupled to first terminal 46 of electric heating element 21. For instance, a portion of first electrical conduit 42 may extend in series between first terminal 46 and infinite switch 110 (e.g., at first voltage path 112). In some such embodiments, first electrical conduit 42 is configured for operating at first voltage, L1, with respect to ground. Thus, first electrical conduit 42 may be coupled or connected to the first voltage source operating at the first voltage L1 with respect to ground.
A second electrical conduit 44 configured for operating at second voltage, L2, with respect to ground. For instance, a portion of second electrical conduit 44 may extend in series between second terminal 48 and temperature switch 36 (e.g., at pole terminal 128). One branch 44A of second electrical conduit 44 may extend in series from first throw terminal 130 to the primary voltage path 114 of infinite switch 110. Another branch 44B of second electrical conduit 44 may extend in series from second throw terminal 132 to the auxiliary voltage path 116 of infinite switch 110. Thus, second electrical conduit 44 may be coupled or connected to the second voltage source operating at the second voltage L2 with respect to ground. The first and second electrical conduits 42, 44 may be any suitable electrical conduits, such as wires, cables, etc.
As described above, temperature switch 36 may selectively adjust between a first and second state. Accordingly, temperature switch 36 may selectively and alternately couple or connect second terminal 48 to primary voltage path 114 and auxiliary voltage path 116. Thus, at a given time, temperature switch 36 can be electrically coupled to only one of primary voltage path 114 and auxiliary voltage path 116. When temperature switch 36 is electrically coupled to primary voltage path 114, temperature switch 36 will be isolated from auxiliary voltage path 116. By contrast, when temperature switch 36 is electrically coupled to auxiliary voltage path 116, temperature switch 36 will be isolated from primary voltage path 114. Based on the temperature, temperature switch 36 may be uncoupled from primary voltage path 114 for coupling with auxiliary voltage path 116, or uncoupled from auxiliary voltage path 116 for coupling with primary voltage path 118. By selectively and alternatively coupling or connecting the second terminal 48 of electric heating element 21 to primary voltage path 114 and auxiliary voltage path, a duty cycle or power output of electric heating element 21 may be varied with temperature switch 36.
Advantageously, power output and temperature may be reduced during use without completely removing power to electric heating element 21. Moreover, temperature swings at heating element 21 may be reduced without the use of multiple coils or additional heating elements.
As illustrated in the example embodiments of
Turning now to
In some embodiments, a switch bracket 76 is provided to hold temperature switch 36. Optionally, switch bracket 76 may include a support tab 92 attached to the panel 20. Temperature switch 36 may be mounted to the support tab 92 at a fixed position relative to the panel 20. In other words, temperature switch 36 may remain stationary relative to the support tab 92 and panel 20, regardless of whether temperature switch 36 engages drip pan 64. In alternative embodiments, support tab 96 may be formed as or include a resilient elastic member to bias switch bracket to drip pan 64. In further additional or alternative embodiments, switch bracket 76, including support tab 92, is mounted directly to a burner box (not pictured), or another suitable support member disposed below drip pan 64.
When assembled in an engaged state, temperature switch 36 may contact drip pan 64. For instance, temperature switch 36 may contact outer surface 74 of drip pan 64. A flat face-plate 38 may directly contact a portion of outer surface 74 of concave sidewall 70. Advantageously, temperature switch 36 may be able to quickly detect and respond to variations in temperature at drip pan 64 and electric heating element 21. Moreover, flat face-plate 38 may allow a point of constant contact between concave sidewall 70 and temperature switch 36, regardless of movement or tolerances of drip pan 64.
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 languages of the claims.
