Induction heaters for heating food, fluids or the like

An induction heater that inductively heats an object, comprising:

• a plurality of coils disposed in a line;
• a power supply unit that supplies high-frequency electric power to the plurality of coils;
• and
• a conveyor belt on a pair of rollers, the conveyor belt including a metal layer and forming a shield between the plurality of coils and a heating element placed on the conveyor belt, the shield allowing a substantial amount of magnetic flux generated by the plurality of coils to pass through the shield.

An induction heater that inductively heats an object, comprising:

• a coil covered with a synthetic resin layer;
• a metallic layer covering the synthetic resin layer;
• and
• a power supply unit that supplies high-frequency electric power to the coil, whereby the coil inductively heats a heating element;
• wherein the metallic layer forms a shield between the heating element and the coil and allows a substantial amount of magnetic flux generated by the coil to pass through the shield.

A cooking apparatus, comprising:

• a heating chamber;
• a heating element disposed inside of the heating chamber;
• a coil that generates magnetic flux which inductively heats the heating element;
• and
• a microwave generator that supplies microwaves in to the heating chamber;
• wherein
• a wall of the heating chamber blocks the microwaves while allowing a substantial amount of the magnetic flux to pass through the wall;
• the coil is disposed outside of the heating chamber and is shielded from the microwaves by the wall;
• and
• the heating element radiantly heats an object to be cooked.

A fluid heating apparatus, comprising:

• a fluid passage defined by a metallic pipe;
• a heating element disposed in the fluid passage;
• a coil disposed outside the metallic pipe;
• and
• a power supply unit that supplies high-frequency electric power to the coil, whereby the coil inductively heats the heating elements,
• wherein the heating element and the coil are located at a first portion of the metallic pipe that has a wall that is thinner than a wall of a second portion of the metallic pipe.