GB860037A - Improvements in or relating to oil furnaces or heaters of the dish-burner type - Google Patents

Abstract

860,037. Controlling burners. KUHLAP-PARATE G.m.b.H. Nov.20, 1957 [Nov. 20, 1956]. No. 36222/57. Classes 75 (1) and 75 (3). A dish-burner comprises starting means adapted to preheat, vaporise and ignite the oil, a first temperature sensitive device adapted to operate a circuit to interrupt the supply of oil to the burner and to remove oil from the burner dish and a second temperature sensitive device adapted to de-energise the starting means when the temperature of a region of the burner is above a predetermined value. The burner shown comprises an oil reservoir 1 from which oil is delivered by a, bucket conveyer 3 to the top of a standpipe 4a connected by an upwardly inclined feed pipe 6 to a central depression 8 in the burner dish 7. The bottom of the standpipe is provided with a valve 5 connected to a bimetallic strip 42, Fig. 5, in such manner that the valve closes when the strip is heated by an electric current. An ignition plug 9 is mounted in the depression 8 of the burner dish with its upper end above the maximum level of the oil and comprises a heat conducting shell surrounding an electrically energised wire spiral the upper portion of which is of finer guage wire than the lower portion and becomes incandescent. The oil vaporized by the lower portion of the ignition plug is deflected by a cap on the end of the plug to pass through an aperture near the upper end of the heat conducting shell into contact with the incandescent wire. The dish 7 has peripheral air intake slits 11 in its side wall and a top plate 12 with a central aperture 13 leading to a combustion chamber 14 having air inlets 15 and separated from a flame chamber 16 by a ring 17. A chimney 18 extends from the flame chamber. Air is supplied by an electric air fan 19. The electric control circuit is shown in Fig. 5 and comprises a main switch 90, a room thermostat 20 and a time switch 21 in the primary of a mains energised transformer the secondary of which includes a chimney thermostat 22, the ignition plug 9, the bimetallic strip 42, the motor for the oil conveyer 3, a switch 23 which opens when the oil tank 1 is empty. the motor for the blower 19 and a switch 24 therefor. At starting 'current flows through the secondary circuit to energise the ignition plug and to operate the oil conveyer and blower motor and to heat the bimetallic strip 42. The latter eventually closes the valve 5 so that oil is supplied to the burner dish 7 and also closes a switch 25 which connects a point 61 on the secondary circuit to a tapping S2 on the secondary winding of the transformer. The ignition plug 9 vaporizes and ignites the oil and eventually the chimney thermostat 22 opens to deenergise the ignition plug. The bimetallic strip 42 and the oil conveyer and blower motor are then energised through the switch 25. When either the room thermostat 20 or the time switch 21 opens the system is de-energised and the bimetallic strip 42 cools to open switch 25 and valve 5 whereupon oil in the burner dish 7 and in the standpipe 4a flows into the oil tank 1. When lack of oil in the tank 1 opens the switch 23 an optical or acoustical signal 71, 72 is energised but the current is so reduced that the motor of the oil conveyer 3 is not operated and the bi-metallic strip again cools to open the valve 5 and the switch 25. The switch 24 for the blower motor may be operated to put the fan in series or in parallel with the chimney thermostat 22. In the former arrangement the blower supplies air only until the chimney is heated. A bimetal strip 91 cuts off the mains supply to the transformer when the temperature thereof reaches a predetermined value.