Patent GB-274478-A (GB)
Title: Improvements in or relating to carbureters for internal combustion engines
IPC: F02M5/02
Filed: 1927-07-13
Abstract: 274,478. Stromberg Motor Devices Co., (Assignees of Hobbs, L. S.). July 16, 1926, [Convention date]. Spray carburettors. - The volume of the air space in the float chamber and the volume of the fuel therein are, so proportioned that, during change of position of the carburettor, the volume of fuel will be suflicient to fill the displaced air space and to keep the entrance to the fuel outlet passage always covered with fuel. The invention is particularly applicable to aircraft carburettors which are at times subjected to violent acceleration and retardation and change of position. The nozzle 13, Fig. 1, is fed from the float chamber 12 which comprises a float 17 pivoted at 19 and acting on the inlet valve 20. An air vent 22 connected by a pipe 23 to the carburettor intake 11 is provided with a check-valve 24 to prevent loss of fuel and the formation of an over rich mixture when flying upside-down. The air space A, which should be as small as possible, is only of sufficient volume to accommodate the inlet valve 20 and permit proper control thereof of the float. The outlet e from the chamber should be at or close to the centre of gravity of the fuel throughout the changes of position. The normal level is: at L-L, but during sudden acceleration, the fuel surface may be in the direction x-x or in extreme cases x<1>-x<1>. With sudden retardation, the fuel would move forwardly and the air would be in the space a - - d, whilst if the aircraft dropped suddenly, as in a pocket, or were turned upside down, the fuel surface would be somewhere in the region. y-y. In all these cases the air space will always be isolated from the outlet orifice e. Extension spaces such as 12' may be provided for storing fuel or for receiving air. In a modification, Fig. 6, two float chambers are provided, one in front of and the other behind the air passage in which the nozzle 33 is loaded; the floats 37 are connected to a pivot shaft 36 by levers which actuate the fuel inlet valve. An air vent 42 is provided with a check valve 43 and the tops of the chambers are connected by a passage 41. Fuel passes to the nozzle 33 by a passage 34. The air spaces at the tops of the chambers are reduced to a minimum, so that even in a case of extremely violent acceleration the air space A, Fig. 6, is well away from the passage 34. The Specification as open to inspection under Sect. 91 (3) (a) describes an idling well and an air-bleed thereto, and also a further modification, Fig. 8 (Cancelled), suitable for use in limited vertical space, in which the float chambers extend only slightly below the outlet passage 47, which is supplied only from the chamber 46, which may be extended rearwardly to increase its capacity. The chambers are connected at the top by a passage 49 and at the bottom by a tube 48 which extends to tha inner wall of chamber 45 but nearly to the outer or rear wall of chamber 46. During acceleration, the front chamber keeps the rear chamber supplied with fuel, but during retardation air spaces may be left at A, A<1>. Escape of any material quantity of fuel from 46 is therefore prevented, and the outlet e remains covered. In a still further modification, Fig. 9 (not shown), the tube 48 extends only to the inner wall of chamber 46 and is provided with a check valve. This subject-matter does not appear in the Specification as accepted.