GB163768A - Improvements in carburettors - Google Patents

Abstract

163,768. Heys, F. A. Feb. 18, 1920. Spray carburettors.-A bulbous or pear-shaped nozzle has one or more fuel orifices opening on to a tapered or curved surface of the nozzle and to the rear side thereof relative to the air flow so that with increased air flow, a region of reduced pressure is formed about such orifice or orifices which region may be increased or diminished in accordance with the speed of the air. The mixing chamber 2 is secured to an enlargement 1<b> of the fuel duct 1<a> by a clip 3. Air enters through ports in the enlarged part of 1<a> to a boss 1<c> on which is screwed the fuel nozzle which has an enlarged portion 6 above which the fuel orifices 7 are located and a tapered portion 6a which extends into the mixing chamber. A valve 8 sliding in the mixing chamber, actuated by a Bowden wire 12 and having a deflecting plate 11, seats on the nozzle at or below the outlets of the fuel orifices 7. A manually actuated throttle valve 18 controls the mixture outlet 10. With the valve 8 well open, the enlargement 6 deflects the air and produces a region of low pressure about the fuel orifices. In a modification, the fuel nozzle encloses an adjustable plate 25, Fig. 4, a notch 27 in which may expose one of several orifices 24 of different sizes. In a further modification, the valve 8 and the throttle valve 18 work side by side in the mixing chamber, the deflector for the mixture being carried by the throttle valve. In a still further modification shown in Fig. 9, the fuel orifices 7 are located in an enlargement extending across the air passage 4, the deflector 11 being carried by the sleeve valve 8 and adapted to seat against the rear surface of the enlargement to close the orifices 7. The sleeve valve is prevented from rotating by a slot 15 therein engaging a pin 14 carried by a clip 17 on the mixing chamber casing. The orifices 7 may deliver, as shown in Fig. 4, into a recess 7a which provides a supply of fuel to facilitate starting. The nozzle may be in the form of two cone frustums arranged base to base and a single annular orifice may be employed. Air inlets may be provided in the end or sides of the mixing chamber, and may be controlled by apertured plates or rings. The Provisional Specification states that the valve 8 may be actuated automatically or partly automatically and partly mechanically.