GB824776A - Electric heating and cooking device - Google Patents

Abstract

824,776. Electrically heated vessels. SUNBEAM CORPORATION. March 12, 1956 [Sept. 23, 1955], No. 7690/56. Class 39(3) [Also in Group XXXVII] A vessel 16 for boiling water for tea and coffee making has a high wattage heater 20 and a low wattage heater 21 attached to its base 16a, and a bimetallic element 26 within a cup-shaped housing 27 extends into the vessel and controls switches 40 and 41, Fig. 8, at predetermined temperatures. The arrangement is such that the heater 20 is first connected to the supply 47, 48 and heats the water to near boiling point very rapidly, whereupon the bimetallic element opens switch 41 and places the heaters in series, and heating to the boiling point is accomplished without excessive steaming and bubbling. The switch 40 is opened and the supply to the heaters cut off if the temperature rises substantially above boiling point, e.g. if the vessel should boil dry. The heating elements are in the form of concentric rings and are preferably of the type comprising a helical resistance within and insulated from an outer metallic sheath. One end of the bimetallic element is secured to the housing 27 and the element is shielded from the heaters by a stainless steel cup 37, although when the switch 41 has been broken and the heater 21 brought into the circuit the heat therefrom prevents closure of the switch 41. An indicating light 70 is connected across the main heating element 20 and goes out when the switch 41 is broken. Switch operation and construction. The switches 40; 41 are mounted on an insulating plate 44 within a housing 18 at the vessel base, and comprise fixed contacts 40b, 41b and movable contacts 40a, 41a on leaf springs 54, 55. The latter are secured at one end to a metal bracket 52 and their opposite ends contact insulated actuating buttons 34, 35 at the movable end of the bimetallic element 26. To provide adjustment of the temperatures at which the switches operate, each switch is associated with a screw 66. Fig. 9, which has a conical part 66b which engages a protuberance 63a on the normally fixed contact. support 63 of the switch so that by turning the screw the normally fixed contact may be adjusted relative the movable one. The housing 18 has openings to provide access to the adjusting screw.