Fluid sprinkling – spraying – and diffusing – Processes – Including mixing or combining with air – gas or steam
Patent
1997-12-09
2000-01-04
Kashnikow, Andres
Fluid sprinkling, spraying, and diffusing
Processes
Including mixing or combining with air, gas or steam
2394195, 239427, B05B 706
Patent
active
06010077&
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a nozzle for delivering a liquid/gas mixture to, for example, the intake manifold or combustion chamber of an internal combustion engine. The nozzle may form part of a fuel injector for an engine, particularly but not exclusively where the injector produces a mixture where a fine mist of fuel droplets are entrained in an airstream prior to being input to a combustion chamber.
Even though the present invention will be described in relation to a preferred application in fuel injectors for internal combustion engines it will be appreciated that it has applicability to any environment where a liquid droplet/gas mixture is to be delivered such that liquid film adherence at a nozzle outlet is to be ameliorated either in continuous or discontinuous delivery systems.
BACKGROUND ART
It is known to create a liquid/gas mixture by delivering a generally cohesive sheet of liquid into a stream of gas flowing through a passage, with the gas acting to shear liquid droplets away from the sheet of liquid. Such a liquid/gas mixture has been found to have a significantly smaller average liquid droplet size than that produced by delivering liquid under pressure through a restricted nozzle to form a spray as many commonly available motor vehicle injectors operate. A liquid/gas mixing apparatus which operates by shearing liquid droplets away from a sheet of liquid is disclosed in U.S. Pat. No. 5,735,468 and which is incorporated herein by reference.
Due to the very small size of the liquid droplets, the liquid/gas mixture produced by shearing liquid droplets from a sheet of liquid using a stream of gas can be delivered along a passage beyond the point at which the liquid is sheared from the sheet, and out through a nozzle.
If a nozzle has a simple continuous expansion zone leading to its outlet, it has been found that such a nozzle delivering liquid/gas mixtures tends to adhere liquid to and build up liquid on the inside surface of the expansion zone, and which liquid is pushed along the passage and out from the outlet as relatively large droplets as compared with the fine mist entrained in the stream of gas flowing into the nozzle.
It would be desirable to eliminate or at least minimize such adherence, build up and delivery of liquid droplets from the nozzle outlet.
The above and other objects and advantages of the present invention are achieved by the provision of a nozzle arrangement for delivering a liquid/gas mixture which comprises a plurality of nozzle assemblies. Each nozzle assembly has a body which includes a flow-through passage leading to an outlet, an expansion zone proximate the outlet, and at least one discontinuity in the expansion zone formed as a radially extending step-wise enlargement followed by a parallel-sided cylindrical portion extending toward the outlet. The discontinuity is adapted to reduce liquid film adherence at the outlet, and the nozzle assemblies are axially aligned and spaced apart by respective gas and/or liquid inspiration zones.
Preferably each discontinuity is substantially of circumferential extent.
The expansion zone preferably has a plurality of discontinuities.
Preferably, the flow passage also has a restriction or compression zone spaced upstream from the expansion zone. The restriction or compression zone is preferably a smoothly converging portion of the flow passage, and which leads to a throat portion which is intermediate the restriction zone and the expansion zone.
The flow passage is preferably generally circular in cross-section as is each expansion zone.
The or each step-wise enlargement in the expansion zone is/are preferably in the form of a circumferential edge having a first diameter, a radially outwardly extending surface which is generally normal to the central axis of the flow passage, and an axially extending cylindrical surface having a second diameter which is a predetermined amount larger than the first diameter, and which leads to the next adjacent step-wise enlargement or the outlet.
In one specific embodiment,
REFERENCES:
patent: 1697334 (1929-01-01), Vitte
patent: 2583726 (1952-01-01), Chalom
patent: 3782639 (1974-01-01), Boltz et al.
patent: 4559275 (1985-12-01), Matt et al.
patent: 4756478 (1988-07-01), Endo et al.
patent: 5294056 (1994-03-01), Buchholz et al.
Kashnikow Andres
O'Hanlon Sean P.
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