Patent GB-252166-A (GB)
Title: Improvements in or relating to controlling apparatus for burners employed in heatingsystems
IPC: F23N5/24
Filed: 1926-05-11
Abstract: 252,166. Socony Burner Corporation, (Assignees of Metcalfe, R. F.). May 14, 1925, [Convention date]. Spray burners; liquidfuel supply. - In a heating apparatus having devices for feeding, igniting and burning oil fuel, a master control is provided comprising an electromagnetic device which during the normal operation of the apparatus remains substantiallv balanced but becomes unbalanced on the opera.- tion of safety devices responsible to abnormal fuel feeding or burning conditions and moves to render the apparatus inoperative. Fig. 1 shows diagrammatically a furnace 1 heated by a burner 2 to which oil is drawn by the suction due to the combustion air supplied by a blower rotated by a motor 4. The control means may comprise a heat-responsive means or thermostat 3 positioned at the place at which it is desired to govern the amount of heat delivered, a safety switch 5 responsive to abnormal fuel-feeding conditions, a safety switch 6 arranged in the furnace and responsive to abnormal conditions such as high steam pressure, safety means 7 situated in the furnace flue and responsive to abnormal heat in the furnace gases, and a weighted " flapper " switch 9 responsive to the condition of the combustible mixture. The electricity is supplied from power lines 11, 12 through a snap switch 14 to main binding posts 16, 17. The blower motor is of the closed armature type and has its field winding 18 connected to the binding posts 16, 17 by lines including an enclosed switch 10. A sparking plug for igniting the fuel mixture is arranged in the secondary circuit 26 of a transformer having its primary winding 24 arranged in parallel with the field winding 18. The ignition is controlled by an arm 32 oscillated bv the variations in magnetic intensity of the transformer core 27 and adapted to make and break at contacts 30, 31 an electric circuit including a winding 28 on the core 27 and two contacts 35, 36, the contact 36 being carried by the switch 9. The electromagnetic device for controlling the operation of the apparatus comprises an electric motor 88 of the repulsion type having its field winding 39 connected to the binding posts 16, 17 and provided with brushes 42, 44, and 45 on its commutator so arranged that when a circuit is completed between the brushes 42, 44 only or the brushes 42, 45 only rotation of the motor takes place in a clockwise or an anti-clockwise direction, but when circuits are completed both through the brushes 42, 44 and 42, 45 the rotation forces balance and the motor comes to rest. The motor drives directly or through gearing the shaft 47 of a distributor 46. The shaft 47 carries a cam 49 operating the switch 10 and an arm 48 fitted with contacts 56, 57. The contact 56 during its rotation wipes a contact segment 55 and the contact 57 wipes a longer contact segment 54 and a. small contact segment 58. The brush 42 and the arm 48 are both earthed, while the brush 44 is connected through a push-button 59 to the segment 58. When the burner is to be started the arm 48 should be in contact with the segment 54 only. When the switch 14 is closed the motor 38 rotates the arm 48 in a clockwise direction owing to the completion of a circuit from the brush 42 to the brush 44 through the thermostat 3, safety switch 5, a relay 79, and safety switch 6, the relay 79 operating to separate contacts 87, 88 in a line connecting the brush 45 with the contact segment 55. The rotation of the shaft 47 closes the switch 10 and thereby starts the rotation of the blower motor 4 and causes sparking at the ignition plug. If the fuel mixture is ignited the switch 9 is moved to separate the contacts 35, 36, thereby stopping sparking at the plug, and to close contacts 84. 85 thereby earthing the brush 45 and completing a circuit between the brushes 44, 45 as the contact 56 engages the segment 55. The motor 38 is consequently brought to rest and the burner continues in operation until abnormal conditions occur. If no ignition occurs the motor 38 continues to rotate until the arm 48 reaches the stop segment 58 when all the motor circuits are opened. By operating the push-button 59 the circuit between the brushes 42, 44 is made and the arm 48 is brought to its initial position. If ignition occurs and there is later failure of combustion the switch 9 resumes its normal " hang " position under the influence of an adjustable weight 82 and breaks the circuit between the brushes 42, 45 thereby causing the motor to rotate until the arm 48 reaches the segment 58. If excessive heat is generated the contacts 71, 76 of the thermostat 3 are separated thereby breaking the circuit between the brushes 42, 44 and causing the arm 48 to return to engagement with the segment 54 only. The opening of the circuit between the brushes 42, 44 causes the relay to release the pivoted arm and allows contacts 87. 88 to engage so that the circuit between the brushes 42, 45 is maintained after the switch 9 is moved to its normal position by the cessation of combustion. The circuit between the brushes 42, 44 is similarly broken by the switch 5 if either an excessively high or low fuel level is reached, or by the switch 6 if abnormal conditions occur in the furnace. The safety device 7 fitted in the furnace flue may consist of a fusible link arranged in the electric supply line. A pilot lamp 60 connected across the lines 11, 12 indicates whether the link has fused. The thermostat 3 comprises a temperature-influenced member 69 carrying an electric contact 71 cooperating with the contact 76 and an element 70 which is subject to the influence of a core 72 wound with a coil 74 included in the circuit between the segment 54 and brush 44. Fig. 4 shows a suitable construction of the switch 9 in which a plate 97 nearly filling an opening 96 in the burner frame is pivoted at 98 so as to engage with roller 102 carried by an arm 100 which is pivoted to a ring 99 surrounding the opening and carries also an adjustable weight 82. When combustion takes place the pressure developed causes the plate 97 to move the arm 100 to the left thereby separating the contact 35 carried by the plate from the contact 36 on the arm 100 and moving the contact 84 on the arm 100 into contact with the contact 85 on an arm 105 on the ring 99. Fig. 6 shows a fuel chamber 106 intended to receive fuel to a normal level 10 through an aperture 109 controlled by a floatoperated needle 112. A plate 116 attached to a second float, 64 engages with stops 67, 68 if an abnormally high or low fuel level is reached and operates the switch 5 provided with the contacts 61, 62, Fig. 1. The opening and closing of the switch 5 may be effected by mercury contained in a tipping reservoir 120.