초록 ▼

An electric cooker or cooking hob has a ceramic plate 2 on which there are a number of hot plate areas each heated by a respective annular heating element 4 disposed within an insulating housing 7. A temperature dependent resistor 9 is disposed below the hot plate area at the center of focus of a re

An electric cooker or cooking hob has a ceramic plate 2 on which there are a number of hot plate areas each heated by a respective annular heating element 4 disposed within an insulating housing 7. A temperature dependent resistor 9 is disposed below the hot plate area at the center of focus of a reflector 8 which is arranged to focus radiant energy from the hot plate area onto the resistor 9 while at the same time shielding the resistor 9 from direct radiation from the electric heating element 4. The signal derived from the resistor 9 is a measure of the temperature of the hot plate and can be used to provide a thermal tripping function to prevent over-heating of the hot plate area and/or to carry out closed loop control of the temperature of the hot plate area. The reflector 8 may be replaced by a shield which shields the resistor 9 from direct heating by the heater. A further annular heating element surrounding the element 4 may be provided, with the control circuitry enabling either the element 4 alone or element 4 plus the outer element to be energized.

대표청구항 ▼

Cooking apparatus including: a glass ceramic hot plate; at least one heater for heating the hot plate disposed within an open-topped insulated housing below the hot plate; and a temperature responsive element spaced from the hot plate by a gap, and disposed, in use, to receive heat energy across the

Cooking apparatus including: a glass ceramic hot plate; at least one heater for heating the hot plate disposed within an open-topped insulated housing below the hot plate; and a temperature responsive element spaced from the hot plate by a gap, and disposed, in use, to receive heat energy across the gap directly from the hot plate, so that the heat energy it receives is primarily radiant energy directly from the hot plate, and to produce a first electrical signal indicative of the temperature sensed thereby; the cooking apparatus also including a further temperature responsive element sensing the temperature of an area of the hot plate shielded from direct heating by the heater and to produce a second electrical signal indicative of the sensed temperature; and control circuitry wherein the first signal is used for maximum temperature cut-out and the second signal is used for closed loop control of the heater.