Patent GB-237074-A (GB)
Title: Improvements in or relating to heating systems
IPC: F24D5/00
Filed: 1924-06-24
Abstract: 237,074. Jackson, W. J. Mellersh-, (Sherman, J. A., and Sheppard, W. H.). June 24, 1924. Electrically controlling fuel and air supplies; liquid-fuel supply ; spray burners.-In a heating system for buildings of the kind in which the supply of air and of oil or other liquid fuel to a burner D, Fig. 2, is controlled by means of an air pump F operated by an electric motor G, the circuit through which is made or broken as the temperature falls below or rises above predetermined values by a switch J under the control of a room thermostat H, the supply of fuel is obtained by the air pressure acting directly upon the surface of the fuel in a container in addition to any suction effect produced by the air supplied for combustion purposes. Also included in the motor circuit between the leads 1, 2, 4, 6, and 8 are a second switch K, which is controlled bv a thermostat P located in the furnace E and adapted to break the motor circuit and stop the pump F whenever, owing to accidental extinction of the pilot burner e, the main burner should fail to be lighted, and a third or snap switch 7, which is operated by a diaphragm M whenever excessive pressure arises in the boiler M<1> and also adapted to break the motor circuit. The main burner itself comprises an outer casing D having an annular passage f<1>, Fig. 2, communicating at one side by an air pipe f with the pump F and at the other side with the space above the fuel in a tank C, and an adjustable inner nozzle d which is supplied with fuel from the tank C, so that air mixed with a supply of fuel drawn up from the tank is projected from the burner and ignited by the pilot burner e, Fig. 1. The thermostat H consists of a contact member 10 connected directly to a main X and associated with maximum and minimum contacts 11, 20, the former contact being connected through a time switch 13 with a line 14 controlling the releasing solenoid 15 of the switch J, while the contact 20 is connected through the time switch 13 with a line 22 controlling the resetting solenoid 23 of the switch J. The time switch is designed so that during the daytime, for example, when a higher temperature is required, the thermostat H is operative, but at night time, when a lower temperature is required, contact at the points 10, 20 is permanently maintained and a second thermostat 234, Fig. 5, provided with maximum and minimum contacts 237, 236 is brought into operation. Selection of the thermostat H or 234 to be operative is effected by a pivoted lever 132, the position of which is regulated by a clockwork-controlled cam 131 and which carries contacts 136, 138 co-operating with contacts 139, 231. The switch K, actuated by the cooling of the furnace owing to failure of the pilot burner to ignite the fuel mixture, is controlled by the thermostat P through lines 25, 28, contacts 29, 30, solenoid 32 and line 33. Energization of the solenoid 32 causes the switch K to open and simultaneously a circuit to be closed through an alarm bell N. The contacts 29, 30 are normally held together by the pressure in the pipe f acting on a diaphragm q, but the contacts are separated when the motor stops and allow the switch K to be reset by hand. The snap switch 7 consists of two arms 74, 75 each pivoted at 71 on an insulating base and connected by a spring 72. When the arm 74 is moved upwardly by actuation of the rod m<2> from the diaphragm M, the spring passes over the dead centre and snaps the arm out of contact with the terminal 73, the circuit being re-established automatically when the boiler pressure falls again.