Self-regulating heater employing reactive components

A heating circuit which consists essentially of

• (A) an AC power supply, and
• (B) a heating unit which comprises
• (a) a reactive component;
• (b) a resistive heating component which is connected to the reactive component by discrete electrical conductors;
• and
• (c) a temperature-responsive component which is not in direct physical contact with the heating component and which has an electrical property which varies with temperature so that the heat generated by the heating unit decreases substantially as the temperature of the unit approaches an elevated temperature.

A self-regulating electrical heater which

• (A) two connection means which are connectable to a power supply;
• and
• (B) a plurality of discrete, spaced-apart heating units, each of said heater units comprising
• (a) an active circuit component;
• (b) a resistive heating component which generates heat when the connection means are connected to a suitable power supply;
• and
• (c) a temperature-responsive component which has an electrical property which varies with temperature so that, when the heater is connected to a suitable power supply, the heat generated by the heating unit decreases substantially as the temperature of the unit approaches an elevated temperature.

An electrical heater comprising:

• (A) two elongate connection means which are connectable to the constant voltage power supply;
• and
• (B) a plurality of discrete, spaced-apart heating units which are electrically connected in parallel with each other between the connection means and each of which comprises:
• (a) a first resistive heating component having a positive temperature coefficient of resistance;
• and
• (b) a second resistive heating component having a zero temperature coefficient of resistance and connected in parallel with the first resistive heating component.

A heating circuit which comprises

• (A) a constant current AC power supply, and
• (B) a heating unit which comprises
• (a) an NTC inductive component;
• and
• (b) a resistive heating component which is connected in parallel with the reactive component by discrete electrical conductors;
• whereby the heat generated by the heating unit decreases substantially as the temperature of the unit approaches an elevated temperature.

A method of heating liquid which comprises placing the liquid in thermal contact with a heating unit which is connected to an AC power supply and which comprises

• (a) a reactive component;
• (b) a resistive heating component which is connected to the reactive component by discrete electrical conductors;
• and
• (c) a temperature-responsive component which is not in direct physical contact with the heating component and which has an electrical property which varies with temperature so that the heat generated by the heating unit decreases substantially as the temperature of the unit approaches an elevated temperature.