GB818695A - Improvements in or relating to devices controlling the feed of liquid fuel to a burner - Google Patents

Abstract

818,695. Valves. WANSON, L. J. July 10, 1957 [Sept. 17, 1956], No. 21947/57. Class 135. A valve unit for controlling the supply of liquid fuel to a burner comprises an electromagnetically operated pilot valve A and a main valve in the form of a piston B working in a cylinder M and forming two chambers, of which the left-hand one P may receive fuel from an inlet 6 through the pilot valve A and a duct 0<SP>1</SP>, and discharge it to the burner through a duct G, while the right-hand chamber P<SP>1</SP> communicates with the inlet 6 through a duct F fitted with an adjustable screw-down valve E, and is provided with a by-pass opening R, the setting of valve E being adjusted to produce a greater pressure drop through duct F than through duct O<SP>1</SP>. The piston B carries valves D, C which control the passage of fuel through ducts G, F, respectively. In the position shown, with pilot valve A closed, fuel from inlet 6 moves piston B to the left so that valve D closes duct G and by-pass R is opened. When pilot valve A is opened by energizing a solenoid 3 the adjustment of valve E ensures that pressure is greater in chamber P than in chamber P<SP>1</SP>, whereby piston B moves to the right, valve C thus closing duct F and valve D opening duct G, enabling fuel to flow to the burner. The piston B may be replaced by a diaphragm, while operation of the pilot valve may be effected pneumatically or hydraulically.