| 摘要 |
<p>1290708 Electrically heated container MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 1 Dec 1969 [29 Nov 1968] 58493/69 Headings A4A and B2 In an automatic electric heating device comprising a container 40 heated by a unit comprising a heating resistor element 43 and a P.T.C. resistor 42 in thermal contact with the container 40 which acts to maintain temperature of the container constant, variations in this temperature due to variations of supply voltage are reduced by a temperature responsive device 44 which responds at a temperature below the desired constant temperature to reduce thermal contact between P.T.C. resistor 42 and container 40. In the rice cooker shown, device 44 is a bi-metallic snap acting disc consisting of an iron-nickel alloy layer and an ironnickel-molybdenum alloy layer. The P.T.C. resistor 42 is a solid solution of semi-conductive barium and lead titanate in the form of a disc and the element 43 is a nickel chrome wire. The bimetallic disc 44 raises the container 40 from thermal contact with P.T.C. resistor 42 at a temperature below the anomaly point whereupon the P.T.C. resistor rapidly reaches its anomaly point to sharply reduce the heating current, which is then predominantly supplied by P.T.C. resistor 42.</p> |
