GB207242A - Air nozzle for liquid fuel burners - Google Patents

Abstract

207,242. Smith, D. Aug. 19, 1922. Spray burners; burners, attaching.-An air admission device for oil burners used in steam-generators comprises a valve member which is slidable coaxially in respect to the fuel supply tube and is adapted to shut off the air supply automatically in the event of an increase of pressure in the combustion chamber such as is caused by backfiring. Figs. 2 and 2<a> show one form in which a pear or onion-shaped valve part 12 slides in the air-admission conduit 2 on a tube 13 which is supported in the conduit 2 by a bracket 14, 15. The oil tube 13 encloses the fuel nozzle 5 which is secured in position by means of a pivoted yoke 29 and screw 30. The valve part 12 is rendered easily movable on the tube 13 by supporting it by means of rollers 20 or by a parallel motion device. In operation the valve part 12 is normally held by the air pressure against a collar 17 on the tube 13 but in the event of a back fire it is moved outwardly into engagement with a packing rib 16 on the conduit 2 and the air supply to the furnaces is cut off. The valve part 12 is fitted with manual operating means such as spindles 22 connected by cross pieces 23, 25. The cross piece 23 is fitted with a screw 24 and is mounted so as to allow it to be turned to permit withdrawal of the burner nozzle. Alternatively the spindles 22 may be secured to or threaded in the part 12. In a modified form the part 12 and the tube 13 are moved towards the furnace to shut off the air supply, a hand-operated sliding member being adapted to engage at one end of its movement with the rear end of the. part 12 and at, the other end of its movement with a stop on the tube 13. In another form shown in Fig. 3 the valve member is constituted by a bell-shaped body 36 forming the outer part of the air admission conduit. The body 36 is supported by pivot arms 35. On an increase of pressure in the combustion chamber the rearward shock is transmitted through passages 40 in the wall of the combustion chamber to the annular space around the body 36 and the body 36 is moved into contact with the stationary part 37 of the air admission conduit to shut off the air supply. The valve is provided with manual operating means preferably connected to the arms 35.