Patent GB-243034-A (GB)
Title: Improvements in carburetters
IPC: F02M1/04
Filed: 1924-05-21
Abstract: 243,034. Hodgson, A. S. May 21,1924. Spray carburettors.- The casing A, Figs. 1 and 2, is provided with a hollow stem a<3> carried by a fixed core a<1> and supplied with aerated fuel, a sliding throttle K connected by a part k<3> to a sliding control rod g<1> operated from a distance by Bowden or other mechanism, a fixed tube H having a conical part h<1>, and a fixed choke tube a<10>. The aerated fuel passes through a port a<11> in the rod g<1>, through a port h<2> in the tube H, and mixes with air in the diffuser chamber Q formed between the tube H and part k<2> of the throttle, the mixture then passing through the throttle ports k<5> to the main air supply passing between the throttle and the choke tube a<10>, which air supply increases as the throttle is opened, the air supply between the tube H and parts k<2> being simultaneously reduced. The fuel is fed from the float chamber C through a passage b<3>, Fig. 2, submerged orifice D, passage b<2> and nozzle b<1>, Fig. 1, to a chamber B communicating through a passage a<4> with the stem a<3>. The depression in the chamber !B is controlled by air admitted through a passage f<5>, the inlet to which is controlled by a tapered port f<4>, Fig. 2, in a rotatable tube F open to the atmosphere; this tube may be used as an altitude control, and may be operated automatically by the variations of the atmospheric pressure acting on a sealed extensible, air container which is spring controlled. In order that air only may be supplied by the carburettor for braking, the fuel supply through the nozzle b<1> may be cut off by setting the tube F so that sufficient air is supplied to nullify the depression in the chamber B. The tube F is provided at the bottom with a restricted orifice f<3> through which, during normal running, air passes to the fuel passage b<2>; at low engine speeds however fuel accumulates in the tube F and seals the orifice f<3>, thus cutting off this air supply and ensuring a richer mixture. Rich mixture for starting is provided by a rotatable tube E, Fig. 2, communicating by a restricted orifice e<3> with the fuel passage b<2>, and having an air inlet tube e<4>, the outlet of mixture being controlled by a tapered port e<10> in the tube E coacting with the inlet to a passage e<9> leading to an annular passage e<11>, Fig. 1, which is provided with an outlet passage e<12> opening into the casing A beyond the throttle. The tube e<4> is rotatable in the tube E to control the air admitted thereto through the ports e<7>, e<8>. The float chamber C is provided with a flange c<2> adapted to be bolted to a flange a<5> on the casing A in any one of a number of angular positions. Fuel is supplied to the float chamber through an inlet c<3>, Fig. 3, filter c<7> and a port, c<8> controlled by a valve c<9> operated from the float through levers, e<13> and a collar c<14>. In engines charged under pressure, the carburettor is fitted between the engine and the compression device, the air pressure at the carburettor air inlet being transmitted to the tube controlling the depression in the chamber B, to the float chamber and to the fuel tank. In the modification shown in Figs. 3 and 4, in which the casing is arranged vertically, (1) the stem a<3> is shortened, the aerated fuel passing through the interior of the throttle and ports k<4> to the diffuser chamber Q and thence to the ports k<5>, (2) the outlet e<16> for starting- mixture is situated in the core a<1>, air being supplied thereto from the interior of the throttle, through a restriction e", (3) the air inlet tube e<5>, Fig. 4, to the starting nozzle is open to the atmosphere at the top and is provided at the bottom with a restricted orifice e<19>; it is also provided with a groove e<20> through which the mixture passes to the outlet port e<10>, control being effected by rotating the tube to vary the position of the groove relatively to the port, and (4) the air supply to the passage f<5> leading to the chamber B passes through an annular chamber f<6> surrounding the tube F<1>, and is controlled either by a rotatable plug f<8> operated from a distance by Bowden mechanism, or by a thermostatic valve controlling the air supply to a pipe m<2> connected to a plug m<1> adapted to be inserted in place of the plug f<8>, the valve being operated by an expansible air or gas container heated from the crank case or by the cooling water. Specification 243,297 is referred to.