Patent GB-706964-A (GB)
Title: Improvements in furnace lighters
IPC: F23D11/42
Filed: 1952-06-06
Abstract: 706,964. Liquid fuel burners. BABCOCK & WILCOX, Ltd. June 6, 1952 [June 6, 1951], No. 14309/52. Class 75 (1) In one aspect of the invention a furnace lighter has a fuel atomizer unit which is projected or retracted by a mechanism into or away from the operative position relative to a main burner, fluid-operated valve means for controlling the fuel flow to a supply conduit leading to the unit and for controlling the flow of a purging fluid to the conduit and means to effect energization of ignition electrodes when the unit is in the operative position, all under the control of an operating means having an operating cycle with four positions whereby in the second position the atomizer unit is projected and supplied with fuel and ignited, in the third position the fuel is shut off, in the fourth position purging fluid is supplied, and in the first position the purging fluid is shut off, and the atomizer unit retracted. In another aspect of the invention a furnace lighter has a plurality of fuel atomizing units associated with individual mechanisms and movable with igniter electrode means on operation of a controller to a projected or retracted position relative to the main burner and the fuel supply to the units is controlled by fluid operated valves to which the fluid supply is controlled by a valve device, means being provided to prevent the valves opening unless all the units are in the projected position and including normally closed valves in series with the valve device and respectively operable to an open position by the mechanisms when the units reach the projected position in which the electrodes are energized to ignite the fuel supplied to the units. The barrel 22, Figs. 1 and 2, of the atomizing unit 20 is slidably mounted in a tube 26 and is moved by a cyclinder 25, Fig. 2, to the projected or retracted position when compressed air is supplied to the cylinder 25 through pipes 52 or 53. In the arrangement shown in Fig. 5 two atomizing units 20, 20<SP>1</SP> are shown and the sequence of operations is effected by cams a, b, c, d, e, f, g and h, mounted on a shaft 105 which is rotated by an element 110 to one of four positions. In the first position as shown the cam a opens a valve A to admit compressed air through pipes 113, 107 and 53, 531 to retract barrels 22, 221. Arms 83, 83<SP>1</SP> release, to close, valves 81, 81<SP>1</SP> as the barrels 22, 22<SP>1</SP> retract and a bellows operated switch 88 is opened to extinguish a lamp 98. The cam d opens a valve D to connect air pipes 52, 52<SP>1</SP>, 101 and 104 to an exhaust pipe 118 and to open a bellows operated switch 103 in order to de-energize the ignition electrodes 23, 24, Fig. 1. The cam f holds open a valve F to connect a pipe 108 to an exhaust pipe 121 and the cam h opens a valve H to connect a pipe 109 to an exhaust pipe 122. The cams b, c and e shut valves B, C and E and cam g enables a valve G to remain closed. On, movement of the element 110 to the second position, Fig. 6 (not shown), the valves A, D and F are closed, valve H is held open, valve G remains closed and valves B, C and E are opened. The closure of valve A and the opening of valve B cuts off the compressed air supply from pipe 113 and opens the pipes 53, 53<SP>1</SP> and 107 to an exhaust pipe 117; the opening of valve C enables compressed air to pass from pipe 116 to pipes 52, 52<SP>1</SP> to move the barrels 22, 22<SP>1</SP> to the projected position and to close the bellows operated switch 103 to energize the ignition electrodes 23, 24; the closing of valve D shuts off the exhaust pipe 118 and the opening valve E places pipe 108 in communication with the pressure fluid supply pipes 91, 86 but fluid will not flow therethrough until the barrels 22, 221 are fully forward to open valves 81, 81<SP>1</SP> by means of the arms 83, 83<SP>1</SP>. When the barrels 22, 221 move forward the valves 82, 82<SP>1</SP> are closed to open a bellows operated switch 96 and extinguish a lamp 97. When the barrels 22, 22<SP>1</SP> reach the projected position the valves 81, 81<SP>1</SP> are opened by arms 83, 83<SP>1</SP> to supply compressed air through a pipe 86 to close a bellows operated switch 88 and light a lamp 98 and through pipe 108 to open a valve 65 in the fuel supply line 60 and operate a threeway valve 70 to connect a pipe 160 to supply fuel to the atomizing unit through pipes 56, 56<SP>1</SP> and to close a fuel return line 67. When the main burner 14, Fig. 1, has been ignited the element 110 is rotated to the third position, Fig. 7 (not shown), to close valve E and open valve F, the valves A, D and G remaining closed, and the valves B, C and H open. The opening of valve F connects the pipe 108 to exhaust 121 and the closure of valve E shuts off the compressed air supply to close valves 65, 70; the valve 70 on closing opens the fuel return line 67. The element 110 is now moved to the fourth position to open the valve G and close the valve H, the valves A, D and E remaining closed and the valve B, C and F remaining open. The opening of the valve G enables compressed air to pass from pipe 116 through a pipe 109 to operate a three-way valve 75 and a valve 80. The operation of the valve 75 closes an exhaust 72 and opens a compressed air or steam supply line 71. The opening of the valve 80 allows the compressed air or steam to pass through the pipe 63 to purge the unit 20 of any residual fuel oil. After completion of the purging operation the element 110 is returned to the first operative position. The valve 70 has a 5 to 15 pounds closing spring and the valve 65 a 16 to 25 pounds closing spring to ensure that the valve 65 opens last and closes first. A throttling valve 165, Fig. 5A, is provided in the supply line 108 before the valve 65. The valve 165 comprises an adjustable needle valve 168 and a ball check valve 172, and the arrangement is such that the check valve 172 is closed when compressed a'r is fed through pipe 108 to open valve 65, the rate of opening of the valve 65 being determined by the adjustment of the valve 168, and the check valve 172 is open when the valve 65 closes to allow an unrestricted passage for the returning air and hence a snap closure of the valve 65. Counter-clockwise rotation of the shaft 105 is prevented by a four-armed cam 111 and a spring 112. The atomizing unit 21 is quickly detachably mounted on the end of the barrel 22 by means of a clamp 58.