Patent GB-318103-A (GB)
Title: Improvements in or relating to control devices
IPC: F22B35/00
Filed: 1929-08-06
Abstract: .318,103. American Radiator Co., (Assignees of Eggleston, L. W.). Aug. 27, 1928, [Convention date]. Ball and float valves; electrically-actuated valves ; fluid-actuated valves; thermally-actuated valves.-A control device actuated by means responsive to a fluid characteristic and having additional means operable indepentently of variations in the fluid characteristic to prevent operation by the main actuating means as described in Specification 273,674 is provided with control means operable by a plunger, said plunger being movable in the opening or closing directions by one or other of two pivoted levers at all times in operative engagement with the plunger. Fig. 7 shows the application of the invention to a heating system comprising a boiler 150 and a heater 153 connected by pipes 151, 152, to the boiler and by pipes 154 155 to a storage reservoir 156, and the return main, respectively. The valve 21 controlling the supply of fuel to the boiler is actuated by a device 160 subject to pressure or temperature conditions in the boiler and acting through levers 161, 49 and link 166 subject to over riding controls 163, 159 and 77, controlled respectively by a thermostat 164 in the reservoir, the water level in the boiler, and the heat of the pilot burner. The control valve 27 has a spindle 26 passing through a stuffing-box 34 into a casing 2, where it is provided with a plate 36 having side flanges 37, 38 and longitudinal extensions 36a, 36<b>. Mounted on the plate 36 is an actuating- member 39 having side members 41, 42 connected by a pin 61 and bent inwardly at the top to form a guide for the lever 49 which passes through vertical slots in the sides of the casing, is pivoted to external lugs 47 and is operative to open the valve 27. A bifurcated member 55 encircling the member 39 is pivoted at 54 to the lever 49 and is slotted at 66 to engage the pin 61. A spring 68 arranged between the casing and a cross bar 60 on the member 55 normally holds the pin 61 against the underside of the lever 49, and operates through the member 55 to open the valve 27. In the form shown in Fig. 5, the member 55 is provided with a pin 141 adapted to be engaged to close the valve by a lever 146 weighted at 147 and connected by a chain to a " motor " 163 controlled by the thermostat 164. In the form shown in Fig. 2, this operation is performed by reversible electric motor 4 acting through reduction gearing to move a pin into engagement with the end 36<a> of the plate 36. A hand-operated device may be fitted to release the plate. A spring-pressed plunger 73 having an actuating-arm 76 working in a slot in the guide tube 71 and connected by a cord 165 to a tumbler weight 159, is released by a float, in the event of the water level in the boiler becoming abnormally low, and engages the bridge 60 to close the valve. This device may be put out of operation by withdrawing the member 76 from the slot and turning it round on the top of the tube 71. A coiled thermal element 98 surrounds the pilot burner 99 and is connected by a pipe 96 to a closed chamber 78 containing an elastic bellows 80. The bellows acts through a spindle 83 on a lever 87 loaded by a spring 95 and provided with a transverse pin 90 adapted in the event of the pilot flame being extinguished to engage the end 36<b> of the plate 36 and close the valve. An adjustable stop 51 is provided for the lever 49 to prevent the main control entirely closing the valve.