초록 ▼

The present invention relates generally to inductive heating, and more particularly to an apparatus and method for non-contact detection and inductive heating of heat retentive food server warming plates used in institutional food service. The invention provides a non-contact detection and control c

The present invention relates generally to inductive heating, and more particularly to an apparatus and method for non-contact detection and inductive heating of heat retentive food server warming plates used in institutional food service. The invention provides a non-contact detection and control circuit for an inductive heating apparatus for heating an inductively reactive heat radiating element built into a warming plate. The warming plate employed by the invention has an integral inductively reactive heat radiating element that is brought to a desired heating temperature such as 450.degree. F. In a preferred embodiment, the apparatus is configured like a conventional industrial cook stove and surface. Underneath the surface is a magnetic inductive coil controlled by the invention for inductively heating a reactive ferromagnetic heat radiating element that is placed on the surface.

대표청구항 ▼

[ What is claimed is:] [1.] An apparatus for non-contact detection and inductive heating of heat retentive food server warming plates having an inductively susceptible material, the apparatus being powered by a three phase AC power source for inducing a single phase alternating current within the in

[ What is claimed is:] [1.] An apparatus for non-contact detection and inductive heating of heat retentive food server warming plates having an inductively susceptible material, the apparatus being powered by a three phase AC power source for inducing a single phase alternating current within the inductively susceptible material to produce heat according to I.sup.2 R, the apparatus comprising:an induction coil, anda detection and control circuit having,a diode rectifier circuit connected to the three phase AC power source for rectifying alternating current into rectified direct current,a direct current filter connected to the diode rectifier circuit for filtering the rectified direct current,an H bridge connected to the direct current filter and having IGBT (Insulated Gate Bipolar Transistor) switches for converting filtered direct current into a single phase alternating current at a preselected frequency, anda load matching circuit connected to a load and the H bridge single phase alternating current and for delivering the stepped up single phase alternating current to the load, the transformer being selected to provide an impedance match between the transistor switches and the load, anda load detecting circuit having an LED detector for detecting the presence of a food server warming plate and an impedance detection circuit for detecting the presence of an inductively susceptible material,wherein the load is a resonant circuit including the induction coil, at least one capacitor for generating an alternating magnetic field, and the inductively susceptible material.