Abstract:
An electrical resistance or heater includes an electrical resistive track provided on an insulating substrate. Two predetermined sections of the track have a predetermined current carrying capacity and are bridged by a glass, ceramic, or glass ceramic material. The configuration of the track and the glass material are such that at a predetermined temperature, the leakage current between the track sections rises to the extent that it causes a current to flow through one or both of the sections which is substantially above its current carrying capability, whereby one section fails.
Abstract:
A liquid heating vessel (6) has a heated base (8) and a thermally sensitive control mounted to the base (8). The control comprises a boiling control for interrupting the supply of energy to the vessel element (12) when liquid in the vessel boils. It is responsive to the liquid temperature in a sump (18) in the vessel base, and comprises a bimetallic actuator (100) in thermal contact with the sump (18) through a C-shaped copper conductor member (110). The vessel also comprises a simmer control operable to maintain the liquid in the vessel at a predetermined temperature after boiling. This control comprises a snap-acting bimetallic actuator through which the current to the element flows to rapidly heat the actuator after a set of contacts is closed, so as to supply energy to the element in short bursts to prevent an audible heating sound.
Abstract:
An energy regulator includes a pivotally mounted, U-shaped bimetallic element, one limb of which acts as an actuator for a microswitch arm, which is pivotally mounted to one end thereof. The other limb acts as a compensating bimetal and has a cam follower that engages a control surface of a control cam. The stressed C spring formed by the microswitch acts to bias the element into a pivotal mount in the housing, to bias the contact arm onto a pivotal seat on the end of the actuator and also generates a moment to bias the cam follower into engagement with its control surface.
Abstract:
An electric coffee maker (2) comprises a first chamber (4), and a second chamber (6) arranged on top of the first chamber. A tube (8) extends down from the second chamber (6) into the first chamber (4) for transferring liquid between the two chambers. The base (20) of the first chamber (4) is provided with electric heater (24) and a thermally responsive control (46) is provided associated with the base (20) so as to be responsive to the temperature of the heater (24) or to a section of the base (20) for interrupting the power supply to or reducing the heating output of the heater (24).
Abstract:
A control for engagement with the external base of a liquid heating vessel comprises a carrier mounting two bimetallic actuators at opposite ends thereof. The actuators operate at the same temperature. Attached to the carrier is a moulding which provides a cordless electrical connector for the vessel, as well as mounting switch means operable by the actuators through push rods. The push rod acts on a leaf spring to open the contacts, and upon further movement engages an arm of a trip lever, so tripping the lever and causing a further arm of the lever to engage the leaf spring open the contacts fully.
Abstract:
An immersion heater has a support plate on which there is provided an electrical heating element in the form of a printed circuit conductive track. The element is provided with a portion which allows it to be clamped in direct relation to a control unit in order to provide direct electrical, thermal, and mechanical connection to that unit. This allows the control unit to operate in the same manner as a control unit connected to a conventional immersion heater. A water heating vessel using the immersion heater mounted to a control unit through an aperture in the base of the vessel is also disclosed.