Abstract:
In one aspect, an electric cooker comprises a pan that may have a planar upper surface portion, and a lid configured such that condensation that collects on its inner surface drains outside the pan. In another aspect, a serpentine heating element may be mounted to the bottom of the pan along a course that reduces disparity in heating of the upper surface of the pan.

Description:
BACKGROUND 
   There are numerous types of foods that are prepared as thin, flat layers, such as crepes, pita and flatbreads. Such foods may be fairly delicate, and tearing or breaking apart of such foods is frequently undesirable. 
   One example of such a food is the east African staple known as engera. Engera has traditionally been prepared over a wood or other fire on a ceramic cooker that has a relatively flat surface. The engera is traditionally cooked on such a cooker under a cover that may be made from mud or clay. 
   The typical engera is very thin, being prepared from a relatively thin batter made up of water, yeast and flour, such as flour made from sorghum, corn or teff (a plant in the grass family that grows in east Africa). A substantial amount of water vapor is evolved during the cooking process, and dripping or running of condensate onto or into the engera is undesirable. The rapid evolution of steam during the process may indicate that the cooking of the engera is nearing completion. 
   As with other such foods, uniform cooking of the engera benefits from a relatively uniformly heated cooking surface. Substantial variations in the heating of the surface can result in some parts of an engera being overcooked and/or other parts being undercooked. 
   SUMMARY 
   In one aspect, an electric cooker comprises a pan that may have a planar upper surface portion, and a lid configured such that condensation that collects on its inner surface drains outside the pan. In another aspect, a serpentine heating element may be mounted to the bottom of the pan along a course that reduces disparity in heating of the upper surface of the pan. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view of one embodiment of a cooker. 
       FIG. 2  is an isometric view of the cooker of  FIG. 1  with the lid in place. 
       FIG. 3   FIG. 3  is a partial sectional side elevation of the cooker of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   While a cooker of the embodiments discussed below is suitable for cooking a variety of foods, it is also useful for the cooking of engera. The embodiments below may refer to features and aspects with reference to the cooking of engera for illustrative purposes, but this does not limit the use of the devices depicted and described below solely to the cooking of engera. 
   As shown in  FIGS. 1 and 3 , in one embodiment an electric cooker  10  may comprise a lid  20  that may be placed over the pan  21  of the cooker  10 , which may be made of aluminum or other suitable thermally-conductive materials. An electric heating element  22  may be mounted to the bottom of the pan  21 , as in channels formed in the bottom of the pan  21  and defined by depending channel walls  24 . The ends  25  of the heating element  22  may protrude outward to about the periphery of the pan  21  and may be protected by a shield  26  that acts as a receiver for an electric controller (not shown) that supplies electric power to the heating element  22 . The electric controller may be similar in function to those used on electric skillets and like appliances, and controls the temperature of the cooker  10 . 
   The lower portion of the pan  21  may be shielded by a cover  27  that may be fastened to the bottom of the pan  21  by screws or other fasteners. The pan  21  may be supported above a table or other support surface by handles  28  that are mounted to the pan by fasteners such as, for example, screws, and that include depending legs. The handles may be made of a material of comparatively low thermal conductivity, such as a high-temperature plastic. Alternatively, the grip portions of the handles  28  and the bottom of the legs  28  may be made of such low thermal conductivity materials. 
   Referring in particular to  FIGS. 2 and 3 , in one embodiment, the lid  20  may be made of aluminum or other appropriate material able to withstand the heat to which it may be exposed. A knob  30 , that may be of a material of low thermal conductivity, may be mounted at the center of the lid  20 . The lid  20  may have a concave inner surface that, for example, slopes downward and outward from the center, such that condensation on the interior of the lid  20  may run along its inner surface to its periphery. A flange  31  may extend around the periphery of the lid  20  and may comprise a first portion  32  that is sloped more nearly horizontally and a second portion  33  that extends downward from the first portion  32 . The inner wall  34  of the second portion  33  of the flange  31  may have a diameter that is sufficiently greater than the diameter of the pan  21  so that the cover may be moved laterally while covering the pan. Such a loose fit of the cover  20  on the pan  21  and the extending of the second portion  33  of the flange  31  to a level below that of the edge of the pan  21  may allow condensation to wick past the upper edge of the lip of the pan and drip outside the pan  21  rather than dripping into the pan  21 . 
   A vent  35  may be provided in the lid  20  to allow steam to escape and reduce condensation on the interior of the lid  20 . The rapid effusion of steam from the vent  35  may be an indication that the cooking process for engera or the like is approaching, or has reached, completion. The vent  35  may be spaced from the knob  30  such that a flow of steam through the vent  35  is less likely to scald the hand of a person attempting to raise the lid  20  by the knob  30 . 
   Referring to  FIGS. 1 and 3 , in one embodiment, the pan  21  of the cooker  10  may have a generally planar upper surface except for a narrow, shallow, upturned, annular lip  36  around the periphery of the pan  21 . The upper surface of the pan may be coated with a coating that resists sticking, such as fluoropolymer resins, including fluoropolymer resins sold by the DuPont Corporation under the registered trademark TEFLON. 
   The lip  36  of the pan  31  may be of sufficient height to reduce runoff in the event that the surface on which the cooker  10  is placed is not entirely level, but may be low enough to facilitate removal of delicate food items such as engera with a broad, flat-blade tool that can sufficiently support the food item during its removal so that undue breakage or tearing of the food item does not occur. Such damage may occur if the lip is not sufficiently shallow to permit insertion of the tool under the engera or the like at a shallow angle. The pan  21  may be made from a material such as aluminum that has sufficient thermal conductivity and is of sufficient thickness to spread the heat from the heating element  22  across its surface in a relatively uniform manner. 
   To facilitate the even spreading of heat across the surface of the pan, the heating element  22  may be formed in a serpentine manner that provides a relatively small maximum distance between points on the surface of the pan  21  and the nearest portion of the heating element  22 , thereby promoting relatively even heating of the surface of the pan  21 . In one embodiment in which the pan is generally round, and referring to  FIG. 1 , the heating element  22  may comprise a plurality of concentric circular arcs  37  connected at the end by spanning circular arcs  38 . 
   To improve the uniformity of heat distribution at the surface of the pan, the heating element  22  may be mounted below the bottom surface of the pan  21  in channels  23  defined by walls  24  formed in the bottom of the pan that may be flared outwardly at their base. In addition, the thickness of the pan  21  above the top of the channel may be greater than that of portions of the pan remote from the heating element  22 . Both of these measures may increase the uniformity of heating of the upper surface of the pan  21 . The walls forming the channel may be formed integrally with the body of the pan, which may be made by casting or other methods. 
   The heating element  22  may be pressed into the channel  23  and maintained therein by friction and/or by the forming and/or deforming of the walls  24  of the channels. For example, in one embodiment, the walls  24  of the channel  23  may be swaged after mounting of the heating element therein to maintain the heating element in place. Other methods may be used to secure the heating element in the channel  23 . In one embodiment, the heating element  22  may be mounted in the channel  23  such that it is not in tight contact with the top of the channel  23  thereby reducing the direct flow of heat from the top of the heating element to the overlying upper surface of the pan. 
   The cover  27  attached to the bottom of the pan  21  may protect users from inadvertently contacting the heating element  22  or the heated walls  24  of the channel  23 . 
   Although the present invention has been described in considerable detail with reference to certain embodiments, other embodiments are possible. Therefore, the spirit or scope of the appended claims should not be limited to the description of the embodiments contained herein.