GB407106A - Improvements relating to electrically controlled oil burning apparatus - Google Patents

Abstract

407,106. Electrically controlling oilburners. MARSDEN, A., 68, Victoria Street, London. Sept. 27, 1932, No. 26833. [Class 75 (i).] An electrically driven and ignited oil-burning plant includes a single movable member tending a predetermined time after the burner motor has started to open switches in the motor and ignition circuits, and a mechanism responsive to the burner flame normally allowing operation of the ignition switch but preventing operation of the motor switch. In the apparatus shown the movable member consists of a rotor 2 carrying mercury switches 7, 8 arranged in the motor and ignition circuits respectively. On the closure of a switch 32, which may be, for example, a thermostatic switch arranged in the water space of the boiler heated by the burner, current can pass from the mains switch 12 to the burner motor 13, to the ignition transformer 16, to an electromagnet 6, and to a lamp 24, a resistance 23, and a coil 17 heating a metal bar 18. The rotor carries a laminated pole-piece 4 adjacent the electromagnet 6 but is prevented from being turned by the electromagnet 6 from the position shown by a hook 11 on its surface engaging a projection 10 on a lever 9. After a predetermined time the expansion of the bar 18 operates the lever 9 to raise the projection 10 and the rotor 2 will then turn until the polepiece 4 is opposite the electromagnet 6 and both switches 7, 8 are opened, unless ignition of the fuel has previously occurred when a thermally operated switch 25 in the path of the combustion gases closes the circuit to an electromagnet 5 which acts on a laminated pole piece 3 carried by the rotor 2. In these conditions the rotor when the parts 10, 11 are disengaged assumes an intermediate position in which the ignition switch 8 is open and the motor switch 7 remains closed, this being the position for normal operation until the switch 32 opens and the rotor is returned by an attached weight 30 to the starting position. Should the flame become extinguished the electromagnet 5 will be de-energized and the switch 7 will be opened as in the case of non- ignition. When the switch 7 opens the electromagnet 6 is also de-energized and the rotor is held by the engagement of the weight 30 with a stop 34. The rotor can then be returned to the starting position by the operator pressing a switch 28 to energize temporarily the electromagnet 5. The electromagnets may be replaced by bimetallic strips acting when heated to turn the rotor in. the same direction as the electromagnets.