Feed Unit For A Fuel Burner

Abstract

A feed unit for a fuel burner has first and second conduit means for supplying liquid hydrocarbon and an emulsifying liquid, for example water, to a premixing chamber from which the premixture is conducted to a mixing chamber in which there is an injection nozzle with an opening through which a jet of the emulsion is emitted and causes a member located in the path of the jet to be vibrated so as to emulsify the emulsion.

Description

There are known devices for improving the combustion conditions of liquid hydrocarbons to eliminate smoke, for example, by adding a certain quantity of water in emulsion. Frequently, the supply of hydrocarbon and water, and the resulting emulsion, require conduits of large dimensions mounted in separate installations, often cumbersome and not readily removable, each device being adapted to a single supply type.

It is an object of the present invention to remedy these defects by providing an improved device or unit for emulsifying a liquid in liquid hydrocarbons, particularly for feeding fuel burners, in which the emulsion is produced continuously and burned without recirculation in a premixing system which forms a part of the emulsifying system, thus producing a compact unit of small dimensions.

To this end, the invention provides a feed unit for fuel burners, for the supply of an emulsion of a liquid in a liquid hydrocarbon to a burner, said unit comprising a casing, a premixing chamber in the casing, first conduit means in the casing for conducting liquid hydrocarbon to the chamber, second conduit means in said casing for conducting an emulsifying liquid to the chamber, a plate adjacent the premixing chamber, having passages therein, a mixing chamber into which the premixture of liquid hydrocarbon and emulsifying liquid is conducted from the premixing chamber by the passages in said plate, an injection nozzle in said mixing chamber having an injection opening, and a vibratory member located opposite said injection opening in the path of the jet of premixture issuing from said opening, for emulsifying the premixture.

In accordance with a feature of the invention, the plate, the injection nozzle and the vibratory member are removable and replaceable with others, whereby the same unit may be adapted for use with burners supplied with fuel of different types and in different quantities.

The nature of the invention and the best manner of carrying it out will be more clearly understood from the following description thereof with reference to the accompanying drawings, in which:

FIG. 1 is a side elevation of a feed unit embodying the invention;

FIG. 2 is a sectional view along line II--II of FIG. 1;

FIG. 3 is a sectional view along line III--III of FIG. 4, illustrating a different embodiment of the invention;

FIG. 4 is a sectional view along line IV--IV of FIG. 3;

FIGS. 5 and 6 are plan views of a nozzle and vibratory plate;

FIG. 7 is a sectional view of a detail of FIG. 2;

FIG. 8 is view in elevation of a still different embodiment of the invention;

FIG. 9 is a sectional view along line IX--IX of FIG. 8; and

FIG. 10 is a sectional view along line X--X of FIG. 8.

The embodiment of the invention illustrated in FIGS. 1 and 2 comprises a first supply system or conduit means 1 for supplying hydrocarbon under pressure, for example fuel oil, and a second supply system or conduit means 2 for the supply of an emulsifying liquid, for example water, both supply systems being arranged in a member 3 forming a part of a casing 3a of the unit. The member 3 and the casing 3a form a compact block in the shape of a parallelepiped (FIG. 1) and preferably of square cross section.

The supply systems 1 and 2, to which fluid is supplied by a pump (not shown), connect with passages 1a and 2a which converge and lead into a premixing chamber 4 adjacent a plate 5, preferably circular, provided with converging passages 6 that receive a first premixture which is thereafter distributed in a mixing chamber 7. At the end of this chamber there is mounted an injection nozzle 8 having a slit or opening 8a through which a thin jet of the mixture is delivered and impinges upon a ridge 9a of a flat blade 9 secured by screws 10 to a casing member 11. The blade 9 (see FIG. 6) is relatively thin (of the order of 0.1 millimeter) and comprises two ridges, preferably of the same concavity. The longitudinal median planes of the slit 8a and of the blade 9 are substantially parallel. These planes may be slightly spaced transversely so that the jet issuing from the slit or opening 8a will provide the initial impulse without striking the blade 9 symmetrically, the subsequent vibrations being maintained by the jet issuing from said opening. Several plates 5 may be mounted in series.

A conical recess 5a (FIG. 7) in the plate 5 allows for the creation of whirls which insure a good premixing of the fluids issuing from the passages 1a and 2a; such recess, however, is not absolutely necessary.

The passages 6 in plate 5 are inclined at substantially 45.degree. (see FIG. 7) relative to the axis a--a of the plate, which lies in the horizontal plane A--A passing through the center of the ridge 9a and of the opening 8a, whereby the mixture will be distributed homogeneously within the chamber 7 and a vortex will be formed in said chamber. The plate may have more than two passages 6, for example four.

The ridge 9a of blade 9 is located at a distance, preferably adjustable by means of a thumb screw 12, from the opening of the nozzle 8. A pin 15 on a shaft 16 and connected to the body member 11 permits, when the screw 12 is turned, to move the body member 11 along guide rods 11a to adjust the distance of the blade ridge from the nozzle opening (for resonance of the vibrating system).

The jet issuing from the nozzle opening 8a impinges upon the ridge 9a of the blade 9 (see FIG. 6) and is dispersed in the mass filling the space 13, while assuring a perfect emulsion and at the same time the appearance of mechanical vibrations in the fluid mass, the blade 9 vibrating at great frequency within the said mass. The entire emulsified mixture is thereafter directed toward the injector by a conduit 14, without recirculation, in the passages 1 and 2.

In the embodiment illustrated in FIGS. 3 and 4, water and fuel oil arrive in a common conduit or pipe 120, the thin blade 9 being horizontal and substantially at the right of conduit 14a connected to the burner injector. The opening 8a is formed in a plate 8b secured to the nozzle 8 by screws 8c (FIGS. 3 and 5).

In the embodiment illustrated in FIGS. 8 to 10, the unit comprises assemblies 31, 32 and 33 providing respectively fuel oil, water and premixture circuits and integral with a parallelepipedic member 300 that is preferably of square cross section (see FIG. 8). For adapting the supply of water to variation in the supply of fuel oil to the burner with which the unit of the present invention is to be used (for example, in a two-speed burner), water supply conduit 122 is provided with supply adjusting means, such as a valve 17. When this valve is opened (by releasing button 17a), the water flows through passages 122a, 122b and becomes mixed, in passage 123 connected to a pump (not shown), with the fuel oil flowing from conduit 121. This mixture is directed, through conduit 120a and a conduit (not shown), to the previously described emulsifying system. The corresponding water supply is thus adapted to the highest heating rate. When the valve 17 is closed, the water supply flows into the passage 122a only, whereby the feed unit is adapted for a lower heating rate. For the two heating rates, the emulsion may thus remain a fixed composition.

It will be observed that, in this embodiment of the invention, filters 130, 131, 132, of fritted bronze for example, are interposed in the premixture, fuel oil and water circuits, respectively, so as to retain impurities and prevent damage to the parts, particularly the injection opening.

The unit according to the invention may be readily adapted to different supplies by merely changing the plate 5, the injection nozzle 8 or the plate 8d and blade 9. Moreover, the small external dimensions (parallelepiped) make it a compact system, occupying little space and easy to handle.

Thus, for example, in a unit for use with a boiler furnishing 50 therms per hour, the various elements had the following dimensions:

a. Plate: 14 mm diameter. The plate has two cylindrical passages each 0.5 mm in diameter.

b. Injection nozzle: 10 mm depth.

c. Injection opening: 2 mm high, 0.08 mm wide.

d. Blade: 0.1 mm wide at its end.

e. Distance between blade and injection opening: 0.2 mm.

With this unit it was possible to prepare emulsion mixtures of fuel oil and water comprising between 20 and 30 percent by weight water relative to the total mass of water and fuel oil.

The unit of the present invention may be used for all types of fuel, the absence of recirculation allowing for counteracting the instability of the emulsifying time for certain fuels. It also reduces considerably the amount of unburnt fuel and the formation of soot, thereby increasing the combustion efficiency and contributing to lessening air pollution.

Claims

What we claim is:

1. A feed unit for fuel burners, for the supply of an emulsion of a liquid in a liquid hydrocarbon to a burner, said unit comprising

a. a casing,

b. a premixing chamber in the casing,

c. first conduit means in the casing for conducting liquid hydrocarbon to the chamber,

d. second conduit means in said casing for conducting an emulsifying liquid to the chamber,

e. a plate adjacent the premixing chamber, having passages therein,

f. a mixing chamber into which a premixture of liquid hydrocarbon and emulsifying liquid is conducted from the premixing chamber by the passages in said plate,

g. an injection nozzle in said mixing chamber having an injection opening, and

h. a vibratory member located opposite said injection opening in the path of a jet of premixture issuing from said opening, for emulsifying the premixture.

2. A feed unit as defined in claim 1, wherein said first and second conduit means merge upstream of the premixing chamber into a single conduit means discharging into said premixing chamber.

3. A feed unit as defined in claim 1, wherein the passages in said plate converge in a downstream direction at an angle of substantially 45.degree. to a plane perpendicular to the plate.

4. A feed unit as defined in claim 1, wherein said vibratory member comprises a thin, flat blade.

5. A feed unit as defined in claim 4, further comprising means for adjusting the distance between said blade and said injection opening.

6. A feed unit as defined in claim 4, wherein the longitudinal median planes of said blade and said injection opening are coincident.

7. A feed unit as defined in claim 6, wherein the longitudinal median planes of said blade and said injection opening are parallel and spaced transversely.

8. A feed unit as defined in claim 4, wherein each of said plate, injection nozzle and vibratory blade is calibrated to a particular flow of liquid hydrocarbon, whereby each may be replaced by one of different calibration to provide the desired flow.

9. A feed unit as claimed in claim 4 wherein said injection opening is in the form of a slit facing said blade.

10. A feed unit as claimed in claim 1 further comprising means to produce a vortex stream of the premixture in said nozzle.