Vapor transfer griddle with immersed electrical heating

Abstract

A vapor transfer griddle unit with a planar sheet metal heat conductive top member defining a horizontally extensive griddle, a bottom wall sealed to the top member and defining therewith a corresponding vapor chamber disposed below the griddle, a body of vaporizable heat transfer medium in liquid state partially filling the chamber with a vapor space between the surface of the liquid and the griddle at rest as well as over the range of griddling temperatures, a horizontally extensive electric heating array comprised of horizontally spaced electric heater tube portions extending directly beneath and spaced below the griddle and located above the bottom wall, and a set of griddle supports mutually arrayed with the heater tube portions and extending between and engaging the griddle and the bottom wall to provide a pattern of support across the underside of the griddle to maintain the griddle flat over its range of operation, the supports having openings permitting free self-leveling flow of liquid as well as free flow of vapor in the chamber, the body of liquid fully immersing the array of heater tubes throughout the range of griddling temperatures and comprising liquid which boils under vacuum conditions over the range, the chamber being permanently evacuated to a level sufficient to enable the liquid to so boil and the heater tube portions being heated by electrical resistance elements disposed there within with associated controls to selectively heat the liquid to boil at any desired temperature in the range.