GB461134A - Improvements in or relating to electrically heated hot-water reservoirs - Google Patents

Abstract

461,134. Automatic control systems. STIEBEL, T. Aug. 6, 1935, No. 22180. [Class 38 (iv)] Temperatures.-In an electrically heated water reservoir of the overflow type, the current supply to two or more internal heat ing elements c, d, Fig 1, arranged at differ ent levels is so con trolled by a tilting mercury switch g operated by a therma element e extending through the reservoir that first the circuit is closed through the lower element c until the water is heated to a predetermined temperature of, say, 85‹ C. and then the circuit is opened through the element and closed through the upper element d, which heats the water to a predetermined temperature of, say, 100‹ C., the circuit being finally opened before the whole of the water has been heated to the higher predetermined temperature. The current may be controlled by a five-pole mercury switch, Fig. 2, having a hand-operated switch n between the second and fourth poles. When the switch n is open, the water is heated first by the upper element then by the lower element to a lower predetermined temperature. When the switch is closed, the water is further heated first by the lower element then by the upper element to a higher predetermined temperature, the circuit being finally closed before the whole of the water reaches the higher temperature.