Abstract:
A solenoid for controlling gas flow to a burner of an appliance includes at least one coil configured to receive an electrically charged pulse based on a signal sent from a controller. The solenoid also includes an armature moveable between a first position and a second position by the at least one coil. The armature is configured to remain in one of the first position and the second position until the coil receives the electrically charged pulse. Gas is flowing to the burner of the appliance when the armature is in the first position, and gas is restricted from flowing to the burner when the armature is in the second position.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates generally to cooking appliances, and, more particularly, to methods and apparatus for assembling cooking appliances and controlling gas flow of cooking appliances. 
   Gas fired stoves, ovens, and ranges typically include one or more gas burners, and a main gas line coupled to the gas burners to providing fuel to the gas burners. At least some known cooking appliances include a solenoid valve to control the gas flow to the individual burners. These known cooking appliances include solenoids which require continuous power to control the flow of gas to the gas burners. Specifically, these known solenoids include an armature positionable in an open position and a closed position. To energize these solenoids, an electrical current is provided to the solenoid to produce a magnetic force to keep the armature in the open position, thus allowing gas to flow to the gas burner. When the electrical current is removed from the solenoid, the solenoid is de-energized, and a spring pushes the armature back to the closed position to block the gas flow. As such, the solenoid is continuously energized to supply gas to the gas burners. 
   Additionally, in these known cooking appliances a plurality of gas burners are typically used simultaneously. As such, each solenoid associated with the gas burners in use is energized at the same time. An undesirable high power supply is required to energize each solenoid to control the gas flow to the multiple burners, which increases the operating cost of the cooking appliance. In addition, as the temperature of the solenoid increases during the extended energizing of the solenoids, the heat is transferred to the gas flowing through the solenoid, thus decreasing the density of the gas flowing to the burners and lowering the output rate of the burners. Moreover, as a result of the increase in temperature of the solenoids, the solenoid coil resistance is also increased, thereby decreasing the electrical current and thus reducing the magnetic field produced by the coil. This may lead to de-activation of the solenoid, thus shutting off the flow of gas to the burner. 
   BRIEF DESCRIPTION OF THE INVENTION 
   In one aspect, a solenoid for controlling gas flow to a burner of an appliance is provided. The solenoid includes at least one coil configured to receive an electrically charged pulse based on a signal sent from a controller. The solenoid also includes an armature moveable between a first position and a second position by the at least one coil. The armature is configured to remain in one of the first position and the second position until the coil receives the electrically charged pulse. Gas is flowing to the burner of the appliance when the armature is in the first position, and gas is restricted from flowing to the burner when the armature is in the second position. 
   In another aspect, a cooking appliance is provided. The cooking appliance includes at least one gas burner, at least one solenoid configured to control the flow of gas to a corresponding one of the gas burners, and a controller operatively coupled to each solenoid. Each solenoid is operable in a first state wherein gas is flowing to the corresponding gas burner, and a second state wherein gas is restricted from flowing to the corresponding gas burner. The controller is configured to provide an electrical pulse to each solenoid to control the operation state of the solenoid. 
   In still another aspect, a method for assembling a cooking appliance is provided. The method includes providing at least one gas burner, coupling a gas supply line to each of the at least one gas burner, and coupling a solenoid to each gas supply line such that the solenoid controls the flow of gas to the respective gas burner. Each solenoid includes an armature moveable between a first position and a second position, and wherein gas is flowing to the burner of the appliance when the armature is in the first position, and gas is restricted from flowing to the burner when the armature is in the second position. Each solenoid also includes at least one coil configured to receive an electrically charged pulse. The method also includes coupling a controller to each solenoid to control the position of the armature of each solenoid, wherein the controller is configured to send electrically charged pulses to the at least one coil of each solenoid. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of an exemplary gas range applicable to the present invention. 
       FIG. 2  is a schematic view of an exemplary gas valve assembly applicable to the gas range shown in  FIG. 1 . 
       FIG. 3  is a cross-sectional view of an exemplary latching type solenoid applicable to the gas valve shown in  FIG. 2 . 
       FIG. 4  is a diagram of electrical pulses provided to the latching type solenoid shown in  FIG. 3 . 
       FIG. 5  is a cross-sectional view of another exemplary latching type solenoid applicable to the gas valve shown in  FIG. 2 . 
       FIG. 6  is a diagram of electrical pulses provided to the latching type solenoid shown in  FIG. 5 . 
       FIG. 7  is a diagram of electrical pulses provided to the gas valve assembly shown in  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates a gas cooking appliance in the form of a free standing gas range  10  including an outer body or cabinet  12  that incorporates a generally rectangular cooktop  14 . An oven, not shown, is positioned below cooktop  14  and has a front-opening access door  16 . A range backsplash  18  extends upward of a rear edge  20  of cooktop  14  and contains various control selectors (not shown) for selecting operative features of heating elements for cooktop  14  and the oven. It is contemplated that the present invention is applicable, not only to cooktops which form the upper portion of a range, such as range  10 , but to other forms of cooktops as well, such as, but not limited to, free standing cooktops that are mounted to kitchen counters. Therefore, gas range  10  is provided by way of illustration rather than limitation, and accordingly there is no intention to limit application of the present invention to any particular appliance or cooktop, such as range  10  or cooktop  14 . In addition, it is contemplated that the present invention is applicable to dual fuel cooking appliances, e.g., a gas cooktop with an electric oven. 
   Cooktop  14  includes four gas fueled burners  22 ,  24 ,  26 ,  28  which are positioned in spaced apart pairs  22 ,  24  and  26 ,  28  and adjacent a respective side of cooktop  14 . Each pair of burners  22 ,  24  and  26 ,  28  is surrounded by a recessed area (not shown in  FIG. 1 ) respectively, of cooktop  14 . The recessed areas are positioned below the upper surface  29  of cooktop  14  and serve to catch any spills from cooking utensils being used with cooktop  14 . Each burner  22 ,  24 ,  26 ,  28  extends upwardly through an opening in cooktop  14 , and a grate assembly  30 ,  32  is positioned over each respective pair of burners,  22 ,  24  and  26 ,  28 . Each grate assembly  30 ,  32  includes a respective frame  34 ,  36 , and separate utensil supporting grates  38 ,  40 ,  42 ,  44  are positioned above the cooktop recessed areas and overlie respective burners  22 ,  24 ,  26 ,  28  respectively. 
   The construction and operation of the range heating elements, including cooktop gas burners  22 ,  24 ,  26 ,  28  are believed to be within the purview of those in the art without further discussion. 
     FIG. 2  is a schematic view of an exemplary gas valve assembly  50  applicable to gas range  10  shown in  FIG. 1 . Gas valve assembly  50  controls the gas flow to burner  22 . In the exemplary embodiment, gas valve assembly  50  includes a gas inlet  52  coupled with a main gas line (not shown) for introducing a flow of gas into gas valve assembly  50 . Gas valve assembly  50  also includes a main solenoid  54  positioned downstream of gas inlet  52  for controlling the flow of gas through gas valve assembly  50 . In the exemplary embodiment, main solenoid  54  is a standard, non-latching type, continuous power solenoid. In alternative embodiments, main solenoid  54  may be another type of valve for controlling the flow of gas through gas valve assembly  50 . 
   Gas valve assembly  50  includes a plurality of burner solenoids  56 . Each burner solenoid  56  is coupled to a respective gas conduit  58  in flow communication with a gas supply via main solenoid  54 . In one embodiment, each burner solenoid  56  is a latching type solenoid, as described in detail below. In the exemplary embodiment, gas valve assembly  50  includes five burner solenoids  62 ,  64 ,  66 ,  68 ,  70  for controlling gas flow to burner  22 . In alternative embodiments, more or less than five burner solenoids  56  may be provided, depending on the particular gas range  10 . In the exemplary embodiment, a controller  72  is operatively coupled to main solenoid  54  and burner solenoids  56  for controlling the operational states thereof. In one embodiment, controller  72  is coupled to a power source and facilitates supplying power to main solenoid  54  and burner solenoids  56  to control the operational states thereof. 
   Main solenoid  54  controls the gas flow to solenoids  62 ,  64 ,  66 ,  68 . Specifically, main solenoid  54  is operable in a first or open state of operation and a second or closed state of operation. In the first state of operation, power is supplied to main solenoid  54 , and main solenoid  54  is energized. When main solenoid  54  is in the first state, gas flows to burner solenoids  56 . In the second state of operation, power is not supplied to main solenoid  54 , and main solenoid  54  is de-energized. When main solenoid  54  is operated in the second state, gas is restricted from flowing to burner solenoids  56 . 
   Each burner solenoid  56  is individually operable and controls the gas flow to burner  22 . Each burner solenoid  56  is operable in a first or open state of operation and a second or closed state of operation. In the first state of operation, power is supplied to any or all of burner solenoids  56 , and respective burner solenoids  56  are energized. When burner solenoids  56  are in the first state, gas flows to burner  22 . In the exemplary embodiment, each burner solenoid  56  has a predetermined gas flow rate there through when operated in the first state. As such, a predetermined amount of gas is allowed to flow to burners  22 . In one embodiment, each of solenoids  62 ,  64  has a gas flow rate of 4.4 kilo British thermal units per hour (kBtu/hr), and each of solenoids  66 ,  68 ,  70  has a gas flow rate of 1.13 kBTU/hr. In alternative embodiments, each of solenoids  62 ,  64  have more or less than 4.4 kBTU/hr, and each of solenoids  66 ,  68 ,  70  has a gas flow rate of more or less than 1.13 kBTU/hr. In the second state of operation, power is not supplied to any of burner solenoids  56 , and burner solenoids  56  are de-energized. When burner solenoids  56  is operated in the second state, gas is restricted from flowing to burner  22 . 
   Moreover, gas range  10  includes additional gas valve assemblies  50  for controlling other burners, such as, for example, burners  24 ,  26 ,  28 . Each gas valve assembly is operated in a substantially similar manner as described above to control the operation and gas flow to burners  24 ,  26 ,  28 . In an alternative embodiment, gas valve assembly  50  controls the gas flow to each of burners  22 ,  24 ,  26 ,  28  instead of only one burner  22 . Specifically, gas valve assembly  50  includes a single main solenoid  54  and multiple burner solenoid groups. Each solenoid group includes five burner solenoids  56  in a substantially similar configuration as described above, and each solenoid group controls the flow of gas to a corresponding one of burners  22 ,  24 ,  26 ,  28 . 
     FIG. 3  is a cross-sectional view of an exemplary solenoid  80  applicable to gas valve assembly  50  (shown in  FIG. 2 ), and  FIG. 4  is a diagram of electrical pulses provided to solenoid  80 . In one embodiment, solenoid  80  is a burner solenoid  56  (shown in  FIG. 2 ). In the exemplary embodiment, solenoid  80  includes an armature  82 , a plug  84 , a biasing member  86 , a first coil  88 , and a second coil  90 . 
   Armature  82  is moveable into and out of the gas flow path to allow or restrict the flow of gas through gas conduit  58  (shown in  FIG. 2 ). Specifically, armature  82  is movable between a first position and a second position, corresponding to the first state and second state of solenoid  80 . More specifically, armature  82  is movable towards and away from plug  84 , in the direction of arrow A. In one embodiment, armature  82  is fabricated from a metallic material have magnetic characteristics. Plug  84  is fabricated from a magnetically soft steel material, such that plug  84  can be temporarily magnetized. In another embodiment, plug  84  is fabricated from a weak permanent magnet such as, for example, a ceramic 5 magnet or an Aluminum Nickel, Cobalt (Alnico) permanent magnet. 
   In the exemplary embodiment, biasing member  86  is coupled to armature  82  and plug  84 . Biasing member  86  facilitates biasing armature  82  away from plug  84  by exerting a force on armature  82 . Moreover, biasing member  86  facilitates retaining armature  82  in position to restrict the flow of gas when armature  82  is in the second position. 
   First and second coils  88 ,  90 , respectively, surround armature  82  along a longitudinal axis of armature  82 . In the exemplary embodiment, first and second coils  88 ,  90  are wound in opposite directions such that, when each coil  88  or  90  is activated, an opposite magnetic field is created. 
   As described above, controller  72  (shown in  FIG. 2 ) is operatively coupled with solenoid  80 . Specifically, controller  72  supplies power to first and second coils  88 ,  90 . When controller  72  sends an electrical pulse  96 , such as for example, a positive phase electrical pulse, to first coil  88 , coil  88  produces a first magnetic field to attract armature  82  and move it into the first position. In the first position, armature  82  is positioned adjacent plug  84  and solenoid  80  is operated in the first state. In the exemplary embodiment, solenoid  80  remains in the first state until receiving another electrical pulse from controller  72 . Specifically, armature  82  is retained against plug  84  by a magnetic force between armature  82  and plug  84 . Moreover, solenoid  80  does not require a continuous supply of power to coil  88  to retain armature  82  in the first position. As such, gas range  10  may include an electronic module that provides a smaller power supply, thus reducing the overall product cost of gas range  10 . Additionally, an operating cost of gas range  10  may be reduced by requiring a reduced amount of power to operate. Moreover, solenoid  80  operates at a lower temperature as compared to known solenoids used in gas ranges. As a result, solenoid  80  facilitates reducing Btu decay as compared to known solenoids, thus providing an increased flow rate of gas to burner  22 . Furthermore, solenoid  80  has a reduced risk of coil burnout and/or coil dropout as compared to known solenoids due to the reduced coil temperature. Specifically, the solenoids facilitate avoiding a loss of magnetic force during coil energizing due to a rise in the temperature of the solenoid, and further facilitates avoiding solenoid failure due to loss of magnetic force. Thus, solenoid  80  has an increased reliability as compared to known solenoids. 
   When controller  72  sends an electrical pulse  98 , such as, for example, a positive phase electrical pulse, to coil  90 , coil  90  produces a second magnetic field to attract armature  82  to move into the second position. Moreover, biasing member  86  facilitates moving armature  82  into the second position. In the second position, armature  82  is positioned a distance from plug  84  and blocks the flow of gas through gas conduit  58 . Additionally, biasing member  86  facilitates retaining armature  82  in the second position. 
     FIG. 5  is a cross-sectional view of another exemplary solenoid  180  applicable to gas valve assembly  50  (shown in  FIG. 2 ), and  FIG. 6  is a diagram of electrical pulses provided to solenoid  180 . In one embodiment, solenoid  180  is a burner solenoid  56  (shown in  FIG. 2 ). In the exemplary embodiment, solenoid  180  includes an armature  182 , a plug  184 , a biasing member  186 , and a coil  188  surrounding armature  182  along a longitudinal axis of armature  182 . 
   Armature  182  is moveable into and out of the gas flow path to allow or restrict the flow of gas through gas conduit  58  (shown in  FIG. 2 ). Specifically, armature  182  is movable between a first position and a second position, corresponding to the first state and second state of solenoid  180 . More specifically, armature  182  is movable towards and away from plug  184 , in the direction of arrow B. In one embodiment, armature  182  is fabricated from a metallic material and includes an armature body  190  having a plug end  192  closest to plug  184 . Armature body  190  surrounds a magnetic core  194  within armature  182 . In one embodiment, core  194  is encapsulated in armature body  190  during manufacture of armature  182 . In another embodiment, core  194  is press fit into armature body  190  during manufacture of armature  182 . In the exemplary embodiment, core  194  is positioned proximate plug end  192  of armature  182 . In one embodiment, plug  184  is fabricated from a metallic material, such as, but not limited to, a steel material. 
   In the exemplary embodiment, biasing member  186  is coupled to armature plug end  192  and plug  184 . Biasing member  186  facilitates biasing armature  182  away from plug  184  by exerting a force on armature  182 . Moreover, biasing member  186  facilitates retaining armature  182  in position to restrict the flow of gas when armature  182  is in the second position. 
   As described above, controller  72  (shown in  FIG. 2 ) is operatively coupled with solenoid  180 . Specifically, controller  72  supplies power to coil  188 . When controller  72  sends an electrical pulse  96 , such as for example, a positive phase electrical pulse, to coil  188 , coil  188  produces a first magnetic field to attract armature  182  to move into the first position. In the first position, armature  182  is positioned adjacent plug  184  and solenoid  180  is operated in the first state. In the exemplary embodiment, solenoid  180  remains in the first state until receiving another electrical pulse from controller  72 . Specifically, armature  182  is retained against plug  184  by a magnetic force between armature magnetic core  194  and plug  184 . Moreover, solenoid  180  does not require a continuous supply of power to coil  188  to retain armature  182  in the first position. As such, gas range  10  facilitates operating at a reduced cost by requiring a reduced amount of power to operate. When controller  72  sends an electrical pulse  98 , such as, for example, a negative phase electrical pulse, to coil  188 , coil  188  produces a second magnetic field to attract armature  182  to move into the second position. Moreover, biasing member  186  facilitates moving armature  182  into the second position. In the second position, armature  182  is positioned a distance from plug  184  and blocks the flow of gas through gas conduit  58 . Additionally, biasing member  186  facilitates retaining armature  182  in the second position. 
     FIG. 7  is a diagram of electrical pulses provided to gas valve assembly  50  (shown in  FIG. 2 ). In the diagram, the vertical axis relates to a power output for operating solenoids  56  (shown in  FIG. 2 ), wherein the output is measured in units such as, for example, Watts. The horizontal axis relates to time and is measured in units such as, for example, milliseconds. 
   In operation, controller  72  (shown in  FIG. 2 ) energizes main solenoid  54  (shown in  FIG. 2 ) to allow gas flow to burner solenoids  56  (shown in  FIG. 2 ). Additionally, controller  72  provides electrical pulses to each of solenoids  62 ,  64 ,  66 ,  68 ,  70  (shown in  FIG. 2 ) to control the operation states thereof. In the exemplary embodiment, controller  72  provides electrical pulses to solenoids  62 ,  64 ,  66 ,  68 ,  70  asynchronously to facilitate reducing a total amount of power used in operating gas range  10  (shown in  FIG. 1 ). Specifically, controller  72  provides electrical pulses to only a single burner solenoid  56  at a given time. More specifically, controller  72  provides five electrical pulses to solenoids  62 ,  64 ,  66 ,  68 ,  70  in sequence, wherein each electrical pulse has a predetermined power output and time duration. In one embodiment, the power output to control each burner solenoid  56  is between approximately one and two Watts. In the exemplary embodiment, the power output to control each burner solenoid  56  is approximately one-and-a-half (1.5) Watts. As indicated above, the pulse may have either a positive or negative electrical charge, depending on the type of solenoid  56  used. Moreover, in one embodiment, the amount of time of each pulse to control each burner solenoid  56  is between approximately five and thirty milliseconds. In the exemplary embodiment, the amount of time of each pulse to control each burner solenoid  56  is between approximately ten and twenty milliseconds. Moreover, each sequential electrical pulse is spaced for an amount of time between approximately five and thirty milliseconds. 
   In operation, controller  72  provides the electrical pulses to solenoids  62 ,  64 ,  66 ,  68 ,  70  in a predetermined order. Specifically, in one embodiment, controller  72  provides electrical pulses to each of solenoids  62 ,  64 ,  66 ,  68 ,  70  to operate solenoids  62 ,  64 ,  66 ,  68 ,  70  in the first state. As such, gas range  10  is in the full on position, and a maximum amount of gas flow is provided to a respective burner, such as burner  22  (shown in  FIG. 1 ). In another embodiment, controller  72  provides electrical pulses to each of solenoids  62 ,  64 ,  66 ,  68 ,  70  to operate solenoids  62 ,  64 ,  66 ,  68 ,  70  in the second state. As such, gas range  10  is in the full off position, and a minimum amount of gas flow is provided to a respective burner, such as burner  22 . In yet another embodiment, controller  72  provides electrical pulses to less than all of solenoids  62 ,  64 ,  66 ,  68 ,  70  to change the operation state of the respective solenoids  62 ,  64 ,  66 ,  68 ,  70  to adjust the amount of gas flow to a respective burner, such as burner  22 , to a flow that is between the minimum and maximum amount of gas flow. As such, controller  72  facilitates controlling an amount of gas flow to each burner by controlling the operational state and position of a plurality of burner solenoids  56 . After the cooking process, controller  72  de-energizes main solenoid  54  to restrict gas from flowing to solenoids  62 ,  64 ,  66 ,  68 ,  70 , and thus restricting gas from flowing to burners, such as burner  22 . 
   A gas range is thus provided which controls gas flow to burners in a cost effective and reliable manner. The gas range includes a gas valve assembly having a plurality of burner solenoids for controlling gas flow to respective burners. In the exemplary embodiment, the controller provides electrical pulses to the burner solenoids asynchronously instead of simultaneously, which facilitates controlling the solenoids with a relative low power supply, and thus lowering the operating cost of the gas range. Moreover, the burner solenoids do not require a continuous flow of power to remain in an open position for allowing gas flow. As a result, the gas range may include an electronic module that provides a smaller power supply, thus reducing the overall product cost of the gas range. Additionally, an operating cost of the gas range may be reduced by requiring a reduced amount of power to operate. Moreover, the solenoid operates at a lower temperature as compared to known solenoids used in gas ranges. As a result, the solenoid facilitates reducing Btu decay as compared to known solenoids, thus providing an increased flow rate of gas to the respective burner. Furthermore, the solenoid has a reduced risk of coil burnout and/or coil dropout as compared to known solenoids due to the reduced coil temperature. Specifically, the solenoids facilitate avoiding a loss of magnetic force during coil energizing due to a rise in the temperature of the solenoid, and further facilitates avoiding solenoid failure due to loss of magnetic force. Thus, the solenoid has an increased reliability as compared to known solenoids. 
   While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.