US 2143958 A
Description (OCR text may contain errors)
Jan, 17, 1939. G. wf Pom-lus, JR 2,143,958
FUEL AND AIR MIXING DEVICE l Filed Jan. 2, 1956 Patented Jan. 17, 1939 UNITED sTATEs v,2,143,958 FUEL ANDEAm MIXING DEvxcE George W. Pontius, Jr., South Bend, Ind., assignor to International Engineering Corporation, Chicago, Ill., a corporation of Illinois Application January 2, 1936, Serial No. 57,115=
This invention relates to the mixing of air and fuel, for liquid-fuel burners' and the like, and is illustrated as embodied in burner nozzles for domestic or industrial oil burners. An object of the invention is to provide simple and effective means for atomizing a liquid fuel by a primary air stream under pressure, and then mixing an adequate supply of secondary air with the stream of mixed fuel andprimary air, resultl0 ing in a combustible mixture.
In one desirable arrangement, the air is fed under pressure into an air box mounted on the end of the fuel conduit, the fuel and primary air being mixed at the end of the air box opposite that ,mounted on the conduit and being projected axially outward, while the secondary air is led from the air `box and directed into the axiallyprojected stream of mixed fuel and primary air. The secondary air may, if desired, be projected with a whirling motion through a series of jets.
In several. effective and simple embodiments, the fuel is fed, in a thin film crosswise'of a stream of primary air projected outwardly through the l central portion of the fuel illm, thus giving very effective atomization of the fuel.- Advantage may be taken of this arrangementto utilize the ilimforming means to cooperate with the side wall of the air box to dene an annular discharge passage for the secondary air.
The above'and other objectsandv features of the invention, including various novel combinations of parts and desirable particular constructions, will be apparent from the following description of the illustrative embodiments shown in the accompanying drawing, in which:
Figure 1 is a longitudinal section through one.
Figure 2 is a similar section, on a larger scale, of the means for directing the blast of primary air through the film of fuel; and
Figures 3 and 4 are sections corresponding to Figure 1, but showing modifications.
The device shownin Figures l and 2 comprises a fuel conduit Ill, closed by a suitable plug or integral web l2 some distance from its end. On this conduit is threaded, or otherwise mounted, va sleeve I4 formed axially of the bottom of a cup-shaped air box i6. Air under pressure is fed into the box I6 through a suitable connection I8. The box I6 and the conduit l0 define between them an annular reservoir space for the air.
Beyond the web I2, the conduit l0 is formed with an opening 20 on its side, through which the air enters from the box I6, to pass in a primary air stream out through the end of the conduit,
through a central' conical opening 22 in a fuel `distributor 24 threadedly mounted on the end of the conduit IU. This distributor is formed with an annular groove 26 communicating by means such as a small conduit 28 with the fuel supply in the conduit I0 at the right of the plug I2.
,The distributor 24 has mounted over and spaced slightly from its face a plate 30, formed with a. central opening alined with the opening 22. This defines a narrow space through which the fuel flows in a thin lm crosswise of the primary air stream, which is thus projected through the central portion of the fuel film axially outward and to the left in Figures 1 and 2.
The stream of mixed fuel and primary air passes out through the flaring central opening of an annular cap 32 which is threaded onto the periphery of the distributor 24, and which also serves to clamp the plate 30 in place over the face of the distributor. i
It will'be noted that in\this embodiment, as well as in those hereinafter described, the film of fuel extends transversely across what is in effect the neck of a venturi through which the air is flowing. This produces a suction on the fuel line which aids in feeding the fuel and which, if the lift is not great, can even in some cases be used as the sole agency for feeding the fuel.
The periphery of the cap 32, and a slightly conicallyconverging cap 34 threaded onto and in effect forming a continuation or part of the cylindrical side wall of the air box I6, together define an annular passage directing outwardly a stream of secondary air which envelopes and surrounds and quickly mixes with thecentral stream of mixed fuel and primary air.
The parts of the embodiment of Figure 3 which correspond to those of Figure 1 are designated by the same reference characters increased by 100. This embodiment has its distributor |24 arranged at the end of the assembly, and carried by an annulus |32 having a flared central pri- 'mary air passage. The annulus |32 has secured thereto a cupshaped stamping ||2 formed with an air opening |20, and having welded to its base a nut |36 threaded on the end of the conduit IIB.` The airbox in this case has the converging conical portion |34 integral with its side wall, and has a detachable base |38.
'I'he modification of Figurel 4 has the parts corresponding to those in Figure .ldesignated by the same' reference characters increased by 200. In this embodiment the wall 234 which directs the'secondary air flares slightly, instead of converging, so that the mixture is formed more slowly. I'his is suitable for use in a larger fire box.
While several illustrative embodiments have been described in detail, it is not my intention to limit my invention to those particular embodiments, or otherwise than by the terms of the appended claims.
1. An air and fuel mixing device comprising an air box having an open endand provided with an inlet for air under pressure, a conduit for liquid fuel under pressure extending through the closed end of the box and the end of which is closed, a pair of generally disk-shaped parts which are secured together and mounted on the end of the fuel conduit inside said box adjacent its open end and the periphery of one of which parts is spaced a short distance from the interior of the boxto provide an annular passage for secondary air, said 'parts being in sealing contact with each other in an annular zone just inside said annular passage and being formed just inside said zone with an annular groove and being spaced apart a short distance within said groove so that fuel owing from said groove will form a film crosswise of the air box, said parts having registering central openings communieating with. the interior of the air box to form a passage for primary air whereby such primary air may pass through said lm, and means conx necting said annular groove to the interior of the fuel conduit to receive fuel therefrom.
2. An air and fuel mixing device comprising an air box provided with an inlet for air under pressure, a conduit for liquid fuel under pressure extending through one end of the box and the end of which is closed, a device mounted on the end of the fuel conduit inside said box adjacent its other end and which is smaller than said air box to afford passage for secondary air, said device being formed just inside its periphery with an annular groove and with a space within said groove such that' fuel flowing from said groove will form a film crosswise of the air box, said device having a central opening communicating with the interior of the air box to form a passage for primary air whereby such primary air may pass-through said film, and means connecting said annular groove to the interior of the fuel conduit to receive fuel therefrom.
GEORGE W. PONTIUS, JR.