Controls for electrically heated water boiling vessels
AssigneeOtter Controls Limited
InventorRobert A. O'Neil
Life of this patent
Estimating the term…
Abstract
Described is an electric immersion heating element for a water boiling vessel which has a single thermal sensor which protects the element against overheating by switching on and off dependant on dryness and water boiling conditions.
Claims12
An electric heating element for a water boiling vessel, the element comprising a head plate and a sheathed heating element proper having a hot return portion affixed to the head plate, the head plate and the sheath of the element proper being formed of a material having a low thermal conductivity as compared to copper or brass and the hot return portion of the element proper being affixed to the head plate by means of a highly localized fixation, and an enclosure provided around the hot return portion, the enclosure being such as to admit water thereto when a vessel fitted with the element is filled and such that water will be expelled therefrom by steam generation when the water is boiled, wherein the highly localized fixation of the hot return portion of the element proper to the head plate comprises a high thermal conductivity link passing through the head plate.
An electric heating element for a water boiling vessel, the element comprising a head plate and a sheathed heating element proper having a hot return portion affixed to the head plate, the head plate and the sheath of the element proper being formed of a material having a low thermal conductivity as compared to copper or brass and the hot return portion of the element proper being affixed to the head plate by means of fixation to a highly localized region;
- a bimetallic thermal sensor arranged to be responsive to the temperature of the head plate at said highly localized region of the side thereof which is opposite to the side whereto the hot return portion of the element proper is affixed, wherein the bimetallic thermal sensor is located closely adjacent to the head plate with a heat sink compound thermally coupling said highly localized region of the head plate to the bimetallic thermal sensor;
- and
- an enclosure provided around the hot return portion, the enclosure being such as to admit water thereto when a vessel fitted with the element is filled and such that water will be expelled therefrom by steam generation when the water is boiled.
Dependencies are inferred from the claim text.