GB710805A - Flame supervisory equipment, especially for substantially non-luminous flames - Google Patents

Abstract

710,805. Controlling burners. LANDIS & GYR AKT.-GES. March 31, 1952 [April 5, 1951], No. 8171/52. Class 75 (1) Flame supervisory equipment responding to extinction of a flame to interrupt the fuel supply thereto comprises an ionization detector 1 consisting of two electrodes one having a large surface and extending into the cold core of the flame and the other having a small surface and immersed in a hot part of the flame, a resistance 4 connected in series with the ionization detector to form a first series circuit, and a second series circuit consisting of a glow discharge lamp 15, a winding 14 of a relay and the resistance 4, the whole being so arranged that on application of an alternating voltage 2, 3 across the first series circuit and of a direct voltage u 0 across the second series circuit a rectified voltage drop u 1 appears across the resistance, as a result of the effect of the flame on the ionization detector, in opposition to the direct voltage u 0 , thus preventing ignition of the glow lamp, whereas on falling away of the flame and therewith the rectified voltage u 1 the direct voltage u 0 is permitted to ignite the glow lamp so that direct current flows through the winding of the relay so as to move a change-over switch 17 into inoperative position to discontinue the fuel supply to the flame. The direct voltage u 0 is generated from the alternating voltage 2, 3 by a dry rectifier 6 and a smoothing condenser 9. A second winding 8 is arranged on the core of the relay and is energized by the direct voltage u 0 this energization alone being sufficient to move the change-over switch to the on position. When the glow lamp 15 is ignited, in the absence of a flame, current flows through the first winding 14 in the direction of the broken arrow and the resulting energization opposes the energization by the second winding 8 so that the switch is moved by its spring to the off position. A second glow discharge lamp 16 is included to form a series circuit with the resistance 4 and the first winding 14 and the rectified voltage u 1 , developed when a flame exists, ignites this second glow lamp whereby current flows through the first winding 14 in the direction of the unbroken arrow, the resulting energization assisting the second winding 8 to maintain the switch in the on position.