US3614282A

US3614282A - Method and apparatus for burning liquid fuels

Info

Publication number: US3614282A
Application number: US817419A
Authority: US
Inventors: Laszlo Gabor
Original assignee: Nikex Nehezipari Kulkereskedelmi Vallalat
Current assignee: Nikex Nehezipari Kulkereskedelmi Vallalat
Priority date: 1968-04-20
Filing date: 1969-04-18
Publication date: 1971-10-19
Anticipated expiration: 1988-10-19
Also published as: FR2007489A1; RO56907A; GB1269262A; BE731693A; DE1920624A1; SE347567B; AT298650B; SU445221A3

Abstract

A liquid fuel burner evaporates liquid fuel by extended surface contact between the fuel and a moving stream of combustion gas before introduction of the combustible mixture into a combustion chamber. Unevaporated fuel may be recirculated, and the combustion gas may be heated prior to contact with the fuel, as by admixture with a portion of flue gases.

Description

United States Patent 1,063,412 6/1913 Buckman,Jr

Inventor Laszlo Gabor Budapest, Hungary Appl. No. 817,419 Filed Apr. 18, 1969 Patented Oct. 19, 1971 Assignee Nikex Nehezipari Kulkereskedelmi Vallahat Budapest, Hungary Priority Apr. 20, 1968 Hungary GA-897 METHOD AND APPARATUS FOR BURNING LIQUID FUELS 3 Claims, 15 Drawing Figs.

US. Cl 431/328, 431/330, 431/11, 431/208 Int. Cl F23d 13/14 Field of Search 431/117,

References Cited UNITED STATES PATENTS 1,592,238 7/1926 Walker 431/330 1,676,501 7/1928 Moors 431/208 2,003,700 6/1935 Sloyan 431/208 X 2,661,054 12/1953 Hyatt et a1. 431/11 X 2,735,481 2/1956 Reichhelm 431/346 X 3,199,568 8/1965 Baumanns et al.... 431/328 X 3,238,991 3/1966 Goldmann et al. 431/11 3,263,732 8/1966 Eisenkraft 431/330 X 3,418,979 12/1968 Reichmann 431/328 X FOREIGN PATENTS 471,326 2/1929 Germany 431/330 741,998 12/1955 Great Britain 431/330 Primary Examiner Frederick L. Matteson Assistant Examiner-Robert A. Dua Attorney-Young & Thompson ABSTRACT: A liquid fuel burner evaporates liquid fuel by extended surface contact between the fuel and a moving stream of combustion gas before introduction of the combustible mixture into a combustion chamber. Unevaporated fuel may be recirculated, and the combustion gas may be heated prior to contact with the fuel, as by admixture with a portion of flue gases.

PAIENTEDUBI 19 ml 3 s 1 4, 2 a2 SHEET 10F 3 Fig.7

Fig.4

Fig.5

INVENTOR BY #JW ATTORNEYS PATENTEDUET 19 Ml SHEET 2 OF 3 INVENTOR ATTORNEYS METHOD AND APPARATUS FOR BURNING LIQUID FUELS The present invention relates to apparatus for burning liquid fuels, characterized by vaporization of the fuel prior to combustion.

It is an object of the present invention to provide apparatus for burning liquid fuels, in which combustion of the fuel is substantially complete and the flue gases are substantially free from unburned material.

Another object of the present invention is the provision of apparatus for burning liquid fuels, characterized by novel ways of preheating the gaseous evaporation medium.

Finally, it is an object of the present invention to provide apparatus for burning liquid fuels, which will be relatively simple and inexpensive to manufacture, easy to operate, maintain and repair, and rugged and durable in use.

Other objects and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawings, in which:

FIG. I is a somewhat schematic view, in longitudinal section, of a first embodiment of apparatus according to the present invention;

FIG. 2 is an enlarged fragmentary cross section of a portion of the embodiment of FIG. 1;

FIG. 3 is a top plan view of the structure of FIG. 2;

FIG. 4 is a view similar to FIG. I, but showing a second embodiment of the invention;

FIG. 5 is a view similar to FIG. I, but showing a third embodiment of the invention;

FIG. 6 is an enlarged fragmentary view of a portion of the embodiment of FIG. 5, it being understood that FIG. 6 is to FIG. 5 as FIG. 2 is to FIG. I;

FIG. 7 is a cross-sectional view taken on the line A-A of FIG. 6;

FIG. 8 is a view similar to FIG. I, but showing a fourth embodiment of the present invention;

FIG. 9 is a fragmentary side elevational view of a further embodiment of the present invention, showing only that portion thereof by which the liquid fuel is introduced into the stream of gaseous evaporation medium;

FIG. 10 is a side elevational view of the structure of FIG. 9;

FIG. 11 is a view similar to FIG. I but showing still another embodiment of the invention;

FIG. 12 is also a view similar to FIG. I, but showing a still further embodiment of the invention;

FIG. I3 is a schematic bottom plan view, with parts removed for clarity, of the embodiment of FIG. 12; and

FIGS. 14 and 15 are views similar to FIG. I, but each showing a still further embodiment of the present invention.

Referring now to the drawings in greater detail, and first to the apparatus of FIG. 1, there is shown apparatus for burning liquid fuels, comprising an evaporator I for liquid fuel from a storage container 2 for the principal fuel to be burned. An auxiliary storage container 3 contains a more volatile liquid fuel, which can be evaporated and burned during start-up. Fuel from container 2 or 3 is fed to a distributor 4 in the evaporator I. If desired, the fuel from container 2 can be preheated by preheater 5. The flow of fuel from container 3 is selectively controlled by a valve 6, while the flow of fuel from container 2 is selectively controlled by a valve 7. In either case, the fuel flows to distributor 4, where it encounters vertically spaced

horizontal plates

8 and 9. A plurality of vertical wires 10 extend between

plates

8 and 9, it being understood that liquid fuel flows from distributor 4 down wires I0 filmwise, and then into a collector II.

An evaporation medium in gaseous phase, such as combustion air, passes horizontally about the surfaces of the fuelwetted wires 10 and proceeds to a burner 12. Fuel which does not evaporate during passage along wires 10 is collected in collector II and returned to container 2 by means of a pump 13.

The air which evaporates fuel from wires 19 may be preheated by heater 15 which is upstream of the wires I0 but downstream from the blower I6 by which the air is impelled. Heater I5 may be electrically heated or fired by gas or another fuel, or may be heated by steam or combustion products. Thus, fuel coming from container 2 or 3 passes through conduit I7 and thence through distributor 4 to wires II) and collector II, the evaporated-fuel/comb'ustion-air mixture registering its temperature upon a thermometer I8 or the like on its way to burner I2, from which it issues through a screen I9 that prevents backflash. The thermometer I8 can control the fuel flow and/or the blower I6 and/or the heater I5, so as to maintain a constant predetermined temperature in the burner between the evaporator and the screen I9. The air-fuel mixture is ignited by means of an automatic electrical ignition device (not shown) disposed outside but adjacent screen I9, and which could be represented in the drawings by a simple vertical line adjacent screen I9 outside burner 12.

Referring now to FIGS. 2 and 3, the particular mounting for the wires III will be seen to comprise a hole 20 through upper plate 8 which is larger than the wire It) so that wire 10 is surrounded by an annular opening through which the fuel may blow downwardly by gravity so as to form a continuous film about wire I0. The supports 2I, seen. in FIG. 3, center the upper end of wire III in the hole 20 and also the lower end of wire III in a corresponding hole 22 in lower plate 9.

Referring now to FIG. 4, it will be seen that evaporation can be performed with less than the total quantity of combustion air. The mixture of air and evaporated fuel flows from the evaporator I into a mixing chamber 23" where it is mixed with combustion air supplied through a conduit 24 and then delivered to burner I2.

FIG. 5 shows an apparatus having an evaporator I wherein the evaporator surfaces are provided by vertical plates 25. The plates 25 are attached to the upper and lower plates corresponding to

plates

8 and 9 in FIG. I, in a manner similar to the attachment of wires It). The openings required for the passage of liquid fuel can be provided] by corrugation of the ends of the plates 25 or by corrugations extending their entire vertical height, and the plates may be firmly fixed in slots 26 cut in the upper and lower plates corresponding to

plates

8 and 9 in FIG. I. See especially FIGS. 6 and 7 for this structure by which the flow of liquid fuel is ensured. In order to increase the total surface of plates 25 and improve the heat exchange, the plates 25 may be subdivided into smaller surfaces or provided with latticelike structure of the type of expanded sheet screen or other type.

FIG. 8 shows another embodiment, particularly characterized by means for preheating the combustion air by use of a portion of the flue gases. Preferably, the flue gas is removed from the combustion chamber, and is accordingly at such a high temperature that only a very small amount (about 10 percent) is sufficient to produce the desired temperature of the combustion air for evaporating the fuell. Thus, a temperatureresponsive regulator 27 under the control of a thermometer 28 or the like downstream of the evaporator regulates the quantity of flue gas which is educted through a conduit 29 from the combustion chamber 30, the control 27 and the thermometer 28 being interconnected by a control line 31 in known manner. A throttle valve 32 regulates the amount of combustion air in the conduit 33 into which the conduit 29 empties, and an injector 34i surrounds conduit 29 in conduit 33. The combustion air passing through conduit 33 thus educts flue gases through conduit 29 because of the reduced pressure in the nozzle of injector 34. The amount of educted flue gases can be regulated by moving injector 34 lengthwise in conduit 33 under the control of a rod 35 through a turnbuckle 36.

In the embodiments previously described, the liquid flows by gravity over the film-supporting surfaces. The embodiments of FIGS. 9 and I0 show, however, that these surfaces can be dipped into and out of a supply of the fuel. Thus, in this embodiment, a horizontal shaft 37 rotatably supports a drum 38 which has extended surfaces of wire or plate or the like, the lower half of drum 38 being immersed. in a fuel container 39.

During rotation, the wetted surfaces enter the duct 40 to be subjected to the action of the stream of evaporation medium such as the combustion air.

Also up to this point, the apparatus described has functioned by evaporating films of liquid from supports of extended surface area. However, it is also possible to provide extended contact surface between the liquid and the gas, by other means. Thus, as seen in FIG. 11, an evaporator much like a stripping column may be provided, comprising a plurality of horizontal perforated plates 41 to the upper of which liquid fuel is supplied. The fuel passes downwardly through the plates in the form of dropsand streams, and the evaporating medium from inlet 43 passes upwardly through the plates in countercurrent flow, the unevaporated fuel collecting in a sump 42 whence it may be recirculated by the pump 13 to the fuel storage container 2. In order to avoid the entrainment of droplets of liquid fuel in the emergent stream of vapors, labyrinthine baffles 44 provide a circuitous path for the vapors from which droplets are expelled by their inertia.

The liquid fuel may also be sprayed into the evaporation medium. This possibility is illustrated in FIGS. 12 and I3, in which a vertically elongated chamber 45 receives relatively rapidly upwardly flowing combustion gas through inlet 43, and relatively slowly rising droplets from a sprayer 46, the unvaporized portions of the droplets eventually settling out of the gas whereby the gas and the droplets have substantial movement relative to each other thereby to promote evaporation.

FIG. 14 illustrates a combination of the spray principle of FIGS. 12 and 13 with the vertical wire principle of FIGS. 1, 4 and 8. In the FIG. 14 embodiment, the liquid fuel is sprayed from the sprayer 46, the unvaporized portions of the droplets impinging on the wires and running down into the collector II for recirculation. Instead of wires, obliquely disposed plates can be used in the embodiment of FIG. 14. g In the embodiments described up to this point, the quantity of fuel has been determined by the temperature of the mix ture. However, the quantity of fuel may also be determined by metering the fuel itself. In FIG. 15, fuel is supplied by a metering device 47 such as a metering pump, from container 2 to an evaporator l. The evaporator has surfaces of such extent and the temperature and velocity of the evaporation medium are selected so that the quantity of fuel required for the maximum output will be evaporated. Provided that the predetermined conditions are maintained, the fuel introduced into the apparatus will thus be completely evaporated.

The present invention thus solves the problem of handling incombustible components of the fuel. As is known, certain fuels may contain, for example, 0.3-0.5 percent by weight of incombustibles, which either leave the combustion apparatus as fly ash, or else accumulate in the combustion apparatus as soot. But in the present invention, the fuel is in effect distilled, at least in those embodiments where unevaporated fuel is recycled, so that only the relatively volatile components and hence the combustibles can be burned. The recycled fuel can thus contain precipitates washed down by the flow of fuel over the evaporation surfaces or from the sump of the equipment; and these precipitates can be removed by filtration or centrifugation or sedimentation and decantation, from the fuel that is returned to the fuel storage.

In view of the foregoing disclosure, therefore, it will be evident that all of the initially recited objects of the present invention have been achieved.

Although the present invention has been described and illustrated in connection with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit of the invention, as those skilled in this art will readily understand. Such modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

Having described my invention, I claim: I. Apparatus for burning liquid fuel, comprising an evaporator chamber having boundary walls defining a passageway for a gaseous evaporation medium, extended surface means having surfaces spaced apart in the direction of gas flow and disposed in said passageway between and extending transversely of said walls and wetted by the liquid fuel, an inlet for said gaseous evaporation medium disposed at one end of said passageway, an outlet for a combustible mixture of said evaporation medium and evaporated fuel disposed at the opposite end of said passageway, said surfaces being spaced both from said inlet and from said outlet, means for conducting the liquid fuel onto said surfaces, means to force said evaporation medium through the evaporator chamber along said surfaces to evaporate at least a portion of the liquid fuel in the evaporator chamber, means located before the evaporator chamber for preheating the evaporation medium, means for collecting and recirculating unevaporated liquid fuel, and means for burning the combustible mixture at a location spaced from said evaporator chamber and beyond said outlet and for separating said surfaces from the combustion of said combustible mixture.

2. Apparatus as claimed in claim 1 said surfaces comprising vertically extending wires, and means to supply liquid fuel to upper portions of the wires to flow down the wires in films exposed to the evaporation medium.

3. Apparatus as claimed in claim I, said surfaces comprising a rotor in the evaporator chamber partially immersed in liquid fuel and partially in the path of said evaporation medium.

Claims

1. Apparatus for burning liquid fuel, comprising an evaporator chamber having boundary walls defining a passageway for a gaseous evaporation medium, extended surface means having surfaces spaced apart in the direction of gas flow and disposed in said passageway between and extending transversely of said walls and wetted by the liquid fuel, an inlet for said gaseous evaporation medium disposed at one end of said passageway, an outlet for a combustible mixture of said evaporation medium and evaporated fuel disposed at the opposite end of said passageway, said surfaces being spaced both from said inlet and from said outlet, means for conducting the liquid fuel onto said surfaces, means to force said evaporation medium through the evaporator chamber along said surfaces to evaporate at least a portion of the liquid fuel in the evaporator chamber, means located before the evaporator chamber for preheating the evaporation medium, means for collecting and recirculating unevaporated liquid fuel, and means for burning the combustible mixture at a location spaced from said evaporator chamber and beyond said outlet and for separating said surfaces from the combustion of said combustible mixture.

2. Apparatus as claimed in claim 1, said surfaces comprising vertically extending wires, and means to supply liquid fuel to upper portions of the wires to flow down the wires in films exposed to the evaporation medium.

3. Apparatus as claimed in claim 1, said surfaces comprising a rotor in the evaporator chamber partially immersed in liquid fuel and partially in the path of said evaporation medium.