GB434770A - A control device for gas-heated apparatus for heating liquids - Google Patents

Abstract

434,770. Valves. JUNKERS & CO., GES., 39, Junkerstrasse, Dessau, Anhalt, Germany.-(Assignees of Bosch Akt.-Ges., R. ; 4, Militarstrasse, Stuttgart, Germany) March 15, 1935, No. 8104. Convention date, March 17, 1934. [Class 135] A control device for gas-heated apparatus for heating liquids such as water is provided with a safety-ignition device, a diaphragm 7 acted upon by the water to be heated for con- .trolling the main gas valve 17, and a valve controlled by the heat of the ignition flame situated in the water passages of the gas-control diaphragm so as to influence the pressure difference acting on the diaphragm and thus prevent opening of the gas valve 17 except when the ignition flame is alight. The chambers 8, 9 below and above the diaphragm 7 communicate by passages 33, 34 respectively with a chamber 31 into which fits a member 29 fixed to the lower end of a tube 28 containing water and terminating in a part 26 exposed to the action of the ignition flame 25. A diaphragm 27 grips the lower end of the member 29 by its own resilience and, when the burner 25 is alight, is caused by the expansion of the water in the tube 28 to engage a seating 32. Communication between the chambers 8, 9 through the passages is thus prevented and the flow of water to be heated can thus set up a pressure difference in the chambers 8, 9 to operate the main gas valve 17. If the flame 25 is extinguished, the diaphragm 27 rises due to the contraction of the water in the pipe 28, and the passages 33, 34 prevent the formation of the necessary pressure difference in the chambers 8, 9 to operate the valve 17. If excessive pressure occurs in the pipe 28 the diaphragm gives sufficiently at its edges to allow water to escape or a non-return valve may be provided in the member 29 for this purpose. A non-return ball valve 35 in the member 29 allows water to flow back into the tube when the flame 25 is extinguished. The supply of gas to the ignition flame 25 may be automatically reduced, if the pressure in the tube 28 rises above a certain level, by means of a valve 38 actuated by a spring-controlled diaphragm 37 subject to the pressure in the tube, the diaphragm being so adjusted that when water is flowing it does not act until the diaphragm 27 engages the seating 32. When the draw-off cock is turned off, the water pressure in the chamber 31 rises to that of the water main and causes the diaphragm 27 to be raised to close the gas valve and the diaphragm 37 to be actuated to reduce the supply of gas to the ignition flame 25.