Patent GB-660132-A (GB)
Title: Improvements in or relating to control devices for the supply of gaseous fuel to burners
Filed: 1948-08-13
Abstract: 660,132. Fluid-pressure servomotor-control systems. MOLLER, P. M. BRINK-. Aug. 13, 1948. Convention date, [Jan. 22, 1947] 21349/48. Class 135. [Also in Group XI] A control device for regulating the supply of gaseous fuel to one or more main burners comprises a fuel inlet opening, an outlet opening for conveying fuel to one or more main burners, a pilot burner or igniter head having direct communication with the fuel inlet opening, a main diaphragm valve which, when open, puts the inlet opening in direct communication with the main burners, and at least one subsidiary diaphragm valve, the chambers of the subsidiary diaphragm valve or valves being connected with the chambers of the main valve and with the pilot burner or igniter head in such a manner that when passage of fuel through the main valve is prevented, fuel can pass through the subsidiary diaphragm valve or valves to the main burner or burners. The control device has an inlet opening 2 for the gas supply and an outlet opening 3, leading to the main burner or burners, controlled by the main diaphragm valve comprising a diaphragm 5 and a valve member 4 pressed towards the closed position by a spring 17. The inlet 2 also communicates, through a passage 7, with a chamber 9 beneath the diaphragm 13 of a subsidiary diaphragm valve having a valve member 11 pressed towards the closed position by a spring 12. The chamber 9 communicates through a pipe 24 with a pilot burner 20, and also, through a narrow passage 15, with the space above the diaphragm 13 which connects with the pilot burner 20 through a pipe 25. Before the burner system is ignited discharge of gas from the pilot burner 20 is prevented by a valve 26, which closes the passage through the pipe 24, and by the closing of the end of the passage 23 in the pilot burner 20 (connected with the pipe 25) by a valve member 22 carried by a diaphragm 21. On moving the valve member of the valve 26 against the action of the spring shown gas is allowed to pass through the pipe 24 and through one or more apertures in the diaphragm 21 to be ignited. The diaphragm 21 becomes heated and curves outwardly to open the valve, so that on release of the valve 26 to close the passage through the pipe 24, gas flows through the pipe 25 to the pilot burner 20 to be ignited. The pipe 25 is connected, through a pipe 27 containing a valve 28, with the space above the diaphragm 5 so that, provided that the valve 28 is open, gas flowing through the pipe 25 causes upward movement of both diaphragms 5, 13 to lift valve members 4, 11 and permit flow of gas to the main burner or burners. Should the pilot flame be extinguished the diaphragm 21 cools and closes the end of the passage 23 so that pressure above the diaphragms 5, 13 is restored to close the diaphragm valves and cut off the supply to the main burner or burners. If whilst the burner system is in full operation the valve 28 is closed either manually or by a thermally actuated device or clockwork full gas pressure will be exerted above the diaphragm 5 by gas flowing through the inlet 2 and passages 7, 16 so that the valve member 4 is maintained in the closed position. The valve member 11 will, however, remain in the open position and a reduced flow of gas will pass from the inlet 2 through passage 7, chamber 9, and a passage 18 to the outlet 3, and this reduced flow may be controlled by a valve 19 in the passage 18. An additional pilot burner 29 providing a stronger flame than that of the pilot burner 20 facilitates ignition of the main burner or burners.