초록 ▼

A heat retentive, temperature self-regulating, food retaining apparatus (10) includes a body (12), heat retentive core (14) and magnetic induction heating element (16). The body (12) includes a substantially rigid, heatable, food-contacting wall (18) defining a cavity (24). The core (14) is position

A heat retentive, temperature self-regulating, food retaining apparatus (10) includes a body (12), heat retentive core (14) and magnetic induction heating element (16). The body (12) includes a substantially rigid, heatable, food-contacting wall (18) defining a cavity (24). The core (14) is positioned in the cavity (24), and in thermal contact with the wall (18) for selective heating of the wall (18). The core (14) includes a solid state phase change material for storing latent heat during a solid-to-solid phase transformation at a phase transformation temperature. A resilient material is in contact with the phase change material to permit expansion of the phase change material during a phase transformation. The heating element (16) is in thermal contact with the core (14) for heating the core (14) to a temperature above the phase transformation temperature to effect a phase transformation in the phase change material. The element (16) includes a ferromagnetic material responsive to a magnetic field for inducing an electric current in the element (16) to heat the element (16). The ferromagnetic material has a Curie temperature between the phase transformation temperature and the melting temperature of the phase change material. A food warming device (42) includes a heater (44) having a holder (46), a magnetic field generator (48), and a no load detector (50), and a food retaining apparatus (10) positioned on the holder (46).

대표청구항 ▼

[ What is claimed is:] [1.] A food warming device comprising:a magnetic induction heater including a holder, means for generating a magnetic field, and impedance detection means for detecting impedance of a body positioned in the magnetic field generated by said generating means, and for interruptin

[ What is claimed is:] [1.] A food warming device comprising:a magnetic induction heater including a holder, means for generating a magnetic field, and impedance detection means for detecting impedance of a body positioned in the magnetic field generated by said generating means, and for interrupting the magnetic field when the detected impedance drops below a predetermined impedance value; anda temperature self-regulating device for retaining food and configured to be positioned on said holder and in the generated magnetic field, said food retaining device including a magnetic induction heating element positioned so as to be in thermal contact with food retained by said device for heating said food to a predetermined temperature,said element including ferromagnetic material responsive to the magnetic field for inducing an electric current in said element to heat said element, said ferromagnetic material having a Curie temperature generally corresponding to said predetermined temperature, and an inherent impedance value when said ferromagnetic material is heated above said Curie temperature, said inherent impedance value being relatively lower than the predetermined impedance value so as to cause said impedance detection means to interrupt the generated magnetic field when said ferromagnetic material of said element is heated above said Curie temperature for regulating the temperature of said food retaining device.