GB190264A - Improvements in and relating to carburettors for internal combustion engines - Google Patents

Abstract

190,264. Burnett, J. B. Sept. 26, 1921. Spray carburettors.-Air enters at a, Fig. 1, through a removable gauze filter a<2> and the mixture passes to the engine at a<3>, the passage a', a' being controlled by a central transversely-arranged rotatable throttle valve b, which is cut away so as to leave wings b', Fig. 4, in one of which fuel orifices b<3> are formed which communicate with an axial bore b<2> in the throttle. A tube b<4>, fitting this axial bore extends to below the normal fuel level i and is coaxial with the float chamber c which is secured by a flange e<3> on a part e, screwed to a tubular part d which contains the fuel orifice d' and is itself screwed into a spigot portion a<6> of the body a. A box g secured by a cap nut g<4> has a fuel inlet g<3>, a filter g<1> and a sediment trap g<2>. The fuel level is maintained constant by a float c<2> actuating a valve c' through a transverse pin c<3>. The float chamber is open to the air inlet a<1> through a duct a<10>. The fuel orifice d' is controlled by a needle valve f loaded by a spring f<1> and provided with an arm f<3> riding over an inclined edge b<9> of a sleeve b<7> which fits over and moves with an extension b<6> of the throttle valve actuated by an arm b<8>. The arm f<3> is, after adjustment, held against rotation so that, upon movement of the throttle, the needle valve moves axially. Hot air is admitted by a pipe a<8> to the space a<7> between the tubes d, b<4>. In the closed position of the throttle valve, a passage a<5>, Fig. 4, in the body a allows air only to pass to the engine, the fuel being cut off. In a modification, the needle valve is replaced by a sleeve or thimble with inclined edge working over a groove in a reduced end of the tube d, the rod f being screwed into a spring-pressed block adapted to rotate with, and slide axially within the extension b<6> of the throttle and bearing against a screw on the arm f<3>. In a further modification, shown in Fig. 8, the passage a<1>, a<3> is vertical and the float chamber c cast with the body a at one side thereof. A sleeve f<4> on the rod f fits the tube d which has a fuel inlet d<2>. The sleeve f<4> has a slotted hole k and radial slots l and fits tightly over the tube b<4>, which is a sliding fit in the throttle valve. Control is effected by a valve in the hot air passage a<8>. The fuel level is shown at i. With the throttle set for slow running the hole k is barely submerged, but rotation of the throttle to increase the speed will bring the hole below the fuel level. In certain positions of the throttle valve, supplementary air ports in the upper portion thereof may be brought into action. The several orifices b<3> may be replaced by a slit and an ordinary barrel throttle may be used having a ring of ports round the choke bore.