GB1317895A - Carburettors - Google Patents

Abstract

1317895 Surface carburetters IMPERIAL CHEMICAL INDUSTRIES Ltd 2 Sept 1970 [15 Sept 1969] 45290/69 Heading F1B The downstream surface of a member 23, 24 with three-dimensional pores, through which air flows and which is supplied with liquid fuel at a controllable rate, is variably shielded by a shutter 26 movable in a direction substantially parallel to the downstream surface. Fuel is supplied to that part of the member 23, 24 which is first shielded through an orifice 21 and fuel may be supplied to the part 24, separated from the part 23 of greater porosity by a metal strip 25, through an orifice 20. Fuel may be supplied to the orifices 20, 21 from a float chamber providing a fuel level at or below the orifice outlets. The porous member may be formed of a naturally occurring material, e.g. sponge or pumice, but is preferably of an artificially produced material, e.g. a solidified foamed liquid or molten material such as a polyurethane, metal or metallized foam. The porous member may comprise a packed mass of a particulate or fibrous material, e.g. glass beads, powdered alumina, glass or metal wool or polymeric fibrous material such as nylon. The packed mass may be bonded into a selfsupporting structure by sintering or with an adhesive. Polymeric fibres having an outer skin of low-melting point polymer may be bonded together at their intersection points by moderate heating without softening the bulk of material. The porous material may be reinforced by incorporating metal wires or mesh, particularly at the downstream surface. The body and shutter of the carburetter may be formed of metal or plastics. In another embodiment, Figs. 1 and 2 (not shown), a horizontal cylindrical tube (10) of poly (4-methypentene-1) contains a block (11) of foamed flexible polyurethane bonded to it with epoxy resin and a plate (13) of poly(4- methypentene-1) is movable downwardly into the tube adjacent the downstream surface of the block. Fuel is supplied to the top of the block (11) through an adjustable needle valve from a float chamber. The shutter may comprise one or more generally laminar members adapted to slide or rotate in the plane of movement, an iris diaphragm or a cam-like rotatable slide. The shutter may be provided with graded apertures moved into and out of the air-flow. The porous member may be formed as an exchangeable cartridge.