Image Number 2 for United States Patent #4233497.
An electric heating element for a cooking apparatus or other device requiring uniform heat generation over an extended area is presented in which the thickness (T) of the electrically resistive heating element increases from the outer edges of the generally disc-shaped element towards the center in inverse proportion to the square of the ratio of the radius (r) at any point to that of the radius at a reference point ("a"), so that ##EQU1## Heating elements fabricated with cross sectional shapes calculated in accordance with the parameters set forth above and disclosed in detail herein and in which the current flow is radial, provide uniform energy release and therefore nearly uniform heat across the surface of the element. Additionally, the absolute element dimensions and masses per unit surface area are small, maximizing rates of desired temperature setting changes. The basic principle is applicable in several technologies related to cooking, e.g., vacuum evaporation.
|
