GB1122067A - Thermostatic control device for controlling a flow of gas - Google Patents

Abstract

1,122,067. Valves. ROBERTSHAW CONTROLS CO. 8 Nov., 1965 [9 Nov., 1964], No. 47292/65. Heading F2V. A gas burner supply system for a heating appliance, e.g. a water heater, is made operative by opening a manual valve 88, Fig. 2, setting the required temperature on the dial 122, Fig. 1, of a thermally responsive valve 90, Fig. 2, and pressing a button 84 to close and open movable closure members 72 and 36, respectively, thereby cutting-off the gas supply to the main burner connection 24 and opening the connection 16 to a pilot burner 22 which is lit by a match. A thermocouple 66 is heated by the pilot burner and energizes an electromagnet 48 to hold the closure member 36 open; upon releasing the button 84 the closure member 72 is spring opened to direct gas to the main burner 30 via the connection 24 which contains the valves 88 and 90. As the water temperature rises it causes elongation of a rod-and-tube thermally-responsive element 124, 126, Fig. 1, which reduces the force on a lever 112 until the set temperature is attained, whereupon a disc-type snap-acting mechanism 102 returns to the position shown and a spring 94 closes the valve 90. Decrease in water temperature causes the valve 90 to open. If the pilot burner is extinguished the electromagnet 48, Fig. 2, is de-energized and the' closure member 36 is seated to shut-off the entire gas supply to the system. The circuit to the electromagnet 48 includes a resistor 54 with a positive temperature coefficient which in the event of a malfunction of the system will reduce the current to the electromagnet and so cause the closure member 36 to be seated when the water attains a given upper temperature. The resistor 54 is positioned in the casing of valve 90 adjacent the thermal element 124, 126, as shown, or in the tube 126 of the latter, in which case it is made up of layers and has a configuration such as to provide the maximum surface in contact with the tube.