Many conventional electric ovens include one or more heating elements mounted at the top of the cooking cavity. These heating elements can be used to heat the cooking cavity to a predetermined temperature. Once the cooking cavity reaches a desired temperature, the heating element is switched on and off to keep the cooking cavity at the desired temperature.
Heating elements located at the top of the cooking cavity can also be used to broil food items located on a rack positioned under the heating elements. During a broiling operation, the heating elements are typically switched on continuously. This causes the heating elements to glow and to emit large amounts of radiant heat.
A rack 106 in the oven provides a cooking surface. The rack can be positioned at different levels within the cooking cavity using rails 104 that are located at different heights within the cooking cavity 102. Thus, food items can be positioned closer to or farther away from the heating element during a broiling operation.
Ovens with a heating element 107 used to conduct broiling operations can include a heat shield or a reflector 109 positioned above the heating element, between heating element 107 and the top wall of the cooking cavity. During a broiling operation, when the heating element 107 remains switched on for long periods of time, the reflector 109 blocks some of the heat produced by the heating element from reaching and damaging portions of the oven located above the heating element. In addition, the reflector 109 can reflect radiation or radiant heat emitted upward from the heating element 107 back downward onto the food items located on the rack 106. This helps to ensure that more of the heat energy produced by the heating element reaches the food items on the rack 106 to conduct a cooking operation.
When a broiling operation is conducted with an oven as illustrated in
The side reflecting portions 122 reflect radiant energy emitted by the straight segments 110 of the heating element located at the left and right sides of the cooking cavity downward towards the top surface of the rack 106 located under the heating elements 110. The side reflecting portions 122 are particularly effective in reflecting radiant energy emitted sideways from the outermost straight segments 110 of the heating element downward. This radiant energy would otherwise travel sideways towards the left and right sidewalls of the cooking cavity 102. By reflecting the radiant energy downward, more of the radiant energy emitted from the outermost straight segments 110 of the heating element ultimately reaches the food items on the rack 106. This can decrease the amount of time required to cook the food items on the sides of the rack 106, and it can also result in more even cooking of the items located across the rack 106. In other words, food items located at the edges of the rack 106 will tend to cook at approximately the same speed as food items located at a center of the rack 106.
The reflector illustrated in
In the embodiment illustrated in
Because some of the radiant energy produced by all of the straight segments 110 is reflected downward by the curved segments 142 at an angle to the vertical direction, a substantial portion of the radiant energy reflected downward from the straight segments located at the left and right sides of the cooking cavity will travel to the sidewalls of the cooking cavity, rather than straight down onto food items on the rack 106. In contrast, the majority of the radiation reflected downward from the straight segments 110 located at the center of the cooking cavity will ultimately travel downward onto food items on the rack 106. The net result is that a greater amount of energy reaches the center portions of the rack than the sides of the rack 106.
An oven having a different type of reflector that is designed to produce more even cooking across the rack is illustrated in
Because the curved segments 152 at the center of the cooking cavity have a large focal length, radiant energy reflected downward from the straight segments 110 of the heating element located at the center of the cooking cavity are reflected downward a large angle with respect to the vertical direction. In other words, the radiant energy reflected downward from the straight segments 110 located at the center of the cooking cavity is reflected off towards the left and right sides of the rack 106. In contrast, because the curved segments 156 located at the left and right sides of the cooking cavity have a smaller focal length, the radiant energy reflected downward from the straight segments 110 located at the sides of the cooking cavity are reflected almost straight down onto the underlying portions of the rack 106.
Because of the varying focal lengths of the curved portions 152, 154, 156 of the reflector 150 illustrated in
In the embodiment illustrated in
In some of the embodiments described above, side reflecting portions and/or a rear reflecting portion are provided on a reflector to help direct radiant energy produced by portions of a heating element located at edges of a cooking cavity downward onto an underlying oven rack. In other embodiments, a front reflecting portion could also be provided on a reflector to help re-direct radiant energy produced by portions of a heating element located at the front of a cooking cavity downward onto an underlying rack.
As described above, a reflector for an electric oven can be designed such that the heat energy produced by a heating element and delivered onto food on an oven rack is distributed evenly across the rack. This can be accomplished using side reflecting portions, a rear reflecting portion and/or a front reflecting portion. This can also be accomplished by providing curved segments designed to reflect radiant energy emitted upward from portions of a heating element downward onto an underlying rack, where the curved segments located at the center of the cooking cavity have a longer focal length than the curved segments located at sides of the cooking cavity. These curved segments could have parabolic or other shapes to help focus the radiant energy toward desired locations.
In the embodiments illustrated above, the heating element includes multiple straight segments that are aligned parallel to each other. In alternate embodiments, the shape of the heating element could take on any desired shape or pattern. However, the concept of reflecting radiant energy produced from portions of the heating element located at sides of the cooking cavity inward with side, rear and front reflecting portions would remain the same. Likewise, the concept of using curved segments with varying focal lengths to achieve a more even distribution of the heat across an underlying rack would also remain the same.
The reflectors illustrated above were shown as being made of one consolidated unitary form. In alternate embodiments, a reflector system made of up multiple different individual reflectors could accomplish the same functions.
Likewise, in the embodiments illustrated above, a single unitary heating element is used. In alternate embodiments, multiple individual heating elements could be used. While the number, orientation and shape of the heating elements could vary, the reflector design considerations would remain essentially the same.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
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