Patent GB-893957-A (GB)
Title: Liquid fuel-fired heating apparatus
IPC: F24C5/18
Filed: 1958-05-05
Abstract: 893,957. Supplying liquid fuel to burners. PRODUITS BRUTS ET MANUFACTURES AU MAROC. May 5, 1958 [May 16, 1957; March 13, 1958], No. 14349/58. Class 75(1) A heating apparatus comprises a vapour burner 9, a casing 5, above the burner providing a heat exchanger and combustion chamber and connected with a flue, a main fuel tank 1 below the burner, a constant level chamber 37, Fig. 7, communicating with the burner through a valve, a pump raising liquid fuel from the main tank 1 to the constant level chamber 37, overflow means for returning excess fuel from the constant level chamber 37 to the main tank 1 and a reserve tank 36, Fig. 7, also supplied by the pump. The casing above the burner is in the form of two casings 5a, 5b, Fig. 4, which have external fins 5c, 5d and which communicate through a conduit 12a. The casing 5a has a horizontal partition 6, Fig. 1, supporting a burner mouth 7 and the casing 5b has a conduit 12b leading to a flue. The burner is pivotally mounted on the end of a rigid fuel supply pipe 20 by means of a pivot pin 86, Fig. 3, engaging a bore 91 in the burner and having a shoulder engaging a bottom wall 87 secured to the casing 5. A nut 89 screws on to the lower end of the pivot pin and clamps to the bottom wall 87 a banjo union 85 on the end of the fuel supply pipe 20. The fuel passes from a duct 90 in the banjo fitting to an axial duct 96 in the pivot pin 86 and then to the bore 91 in the burner. Fuel leaking between the pivot pin and the bore 91 passes through an orifice 97 in the base of a sleeve 93 surrounding the pivot pin and then through a duct 98 in the bottom wall 87 and through a hole 2a in the top 2 of the fuel tank 1. A door 18 in the casing 5 allows the burner to be swung to the outside of the casing for maintenance and ignition. A unit 30 for supplying fuel to the burner comprises a tank, Figs. 5, 6, 7 divided by partitions 35 to form the constant level chamber 37 and the reserve tank 36. The partitions 35 radiate from a large diameter tube 38 extending into the main fuel tank 1 and having a port 39 determining the level of the fuel in the constant level chamber 37. The level of the fuel in the reserve tank 36 is determined by a notch 40 in the top edge of one of the partitions 35 which allows excess fuel in the reserve tank to flow into the constant level chamber 37. The pump for lifting the fuel from the main tank 1 into the compartments 36, 37 of the fuel unit 30 comprises a rod 45, Fig. 6, having a square screw thread and disposed within a tube 41 extending through the large diameter tube 38 to the main fuel tank 1. The threaded rod 45 is rotated by an electric motor 47 mounted on the cover of the fuel supply unit; the coupling between motor and the threaded rod being a spring 49. Holes 53 which may be located at different levels in the tube 41 discharge the fuel from the pump into the compartments 36, 37. The valve for controlling the flow of fuel to the burner comprises a piston 56, Figs. 5, 6, slidably mounted in a bore in a solid member 55 and having a tapered flange at its base pressed against a tapered seat on the solid member 55 by a spring 59 interposed between the piston and a screw plug 60. The upper part of the piston has only slight clearance with the bore in the solid member 55 but the lower part of the piston is of reduced diameter Two diametrically opposed ducts 63, 64 in the solid member 55 connect respectively with the constant level chamber 37 and with a socket in which the fuel pipe 20 is connected; another duct 68 connects the constant level chamber 37 with the reduced diameter part -of the piston 56; and a further duct 69, Fig. 6, connects the reserve tank 36 with a chamber 70 at the base of the bore in the solid member 55. The valve is operated by a cam 71 on a shaft 72 operated by a lever 73. In the "off" position of the level the piston 56 is in its uppermost position, Fig. 5, and cuts off communication between the two opposed ducts 63, 64 and between the duct 68 and the duct 69. Rotation of the cam 71 from the off position progressively brings a groove 57 in the piston 56 into alignment with the two opposed ducts 63, 64 to increase the flow of fuel to the burner; the piston flange moves from its seat and connects the ducts 68, 69 to allow fuel to flow from the reserve tank 36 to the constant level chamber 37. In th highest fuel supply position of the piston 56 the operating lever is under the action of a spring which returns it to a lower flow rate position when it is released The shaft 72 carries a second cam 75, Fig. 6, which closes a switch to energize the motor 47 driving the pump when the operating lever is moved from the "off" position, and a third cam, which closes a switch in the circuit of an ignition resistance, when the operating lever is moved to a low flow position of the fuel valve an opens the switch in all other positions. In a modified construction the ignition resistance is connected in parallel with the electric motor and a thermostat responsive to the combustion gases de-energizes the resistance. A device may be included for automatically igniting the burner at a predetermined time. The ignition resistance may be supplied from a step down transformer. The ignition resistance is mounted on the burner and is connected to contact strips adapted to engage with bent elements mounted on the casing 5a when the burner is in its operating position.