| 摘要 |
1,143,210. Controlling burners. CONTROLS CO. OF AMERICA. 10 Aug., 1966 [13 Sept., 1965], No. 35736/66. Heading F4T. In a burner ignition and fuel control system an igniter 12 having spaced electrodes 11, 13 which also act as a flame sensor is connected in the secondary circuit of a transformer 16 of which the primary coil 20 is connected to an electrical source 22 through a pulsing circuit 24 and a fuel control valve 14 electromagnetically operated through a coil 15 connected in an emitter-follower circuit including a transistor 40. When ignition voltage is applied to igniter 12 with no flame, a high voltage is applied to a gate 52 of transistor 40 rendering the latter conductive to pass sufficient current to open valve 14 and when a flame occurs the ionization potential at the electrodes 11, 13 results in a reduction in potential of gate 52 to reduce the current to a holding value. A silicon controlled rectifier 64 controls current flow in a path 62 of a voltage sensitive circuit 60 so that if ignition fails a shunt circuit to ground is established around valve coil 15 to close the valve and cause a lock-out condition which can be reset by the momentary opening of a switch 80 in the main supply line. |
