US3341131A - Liquid fuel burner having plural whirl patterns of varying radii - Google Patents

Description

Sept. 12, 1967 H. G. STALLKAMP 3,341,131

LIQUID FUEL BURNER HAVING PLURAL WHIRL PATTERNS OF VARYING RADII Filed June 16, 1965 2 Sheets-Sheet l FIG.2

41 42 3K V f) 43 3a 33 37 "36 J4 INVENTOR Huben G. STaIIkamp ATTORNEY Sept. 12, 1967 H. G. STALLKAMP 3,341,131

LIQUID FUEL BURNER HAVING PLURAL WHIRL PATTERNS OF VARYING RADII Filed June 16, 1965 2 Sheets-Sheet 2 FIG. 3

capacity of such atomizers may thereby United States Patent 3,341,131 LIQUID FUEL BURNER HAVING PLURAL WHIRL PATTERNS OF VARYING RADH Hubert G. Stallkamp, Akron, Ohio, assignor to The Babcock & Wilcox Company, New York, N.Y., a corporation of New Jersey Filed June 16, 1965, Ser. No. 464,334 4 Claims. (Cl. 239-402) The present invention relates to liquid fuel burners, and more particularly to fluid atomizing fuel burners for erosive liquid fuels.

In the successful combustion of a liquid fuel it is desirable to atomize the fuel to a fine mist so that combustion air can be intimately mixed therewith to complete the combustion process. Some liquid fuels, such as the residual liquors resulting from a cellulosic pulping proc ess, are so erosive, as to reduce the atomizing eifect of one or more of the atomizer parts, necessitating frequent replacement of those parts. Residual liquors resulting from the sulphite cooking process are particularly erosive due to dissolved and suspended solid matter therein and also frequently contain fibrous material which tends to plug small diameter liquor flow passages in atomizer parts.

In accordance with the present invention I provide a liquid fuel burner assembly constructed and arranged to successfully atomize erosive liquids without excessive wear on the atomizer parts. This is accomplished by a novel arrangement of atomizing fluid flow passageways arranged to intersect a high velocity flowing stream of the liquid to be atomized. The atomizing effect is accomplished out of direct contact with the confining liquid flow passageway, which is relatively unobstructed, to avoid excessive erosion of the atomizer parts and pluggage due to the presence of fibrous materials in the liquid.

The invention described herein is an improvement over the invention disclosed in US. Patent 2,812,212, issued Nov. 5, 1957, in the name of Rogers et al. In order to obtain higher capacities in fuel burners of the type described in the aforesaid patent without substantial increase in the pressure at which the liquid to be atomized is supplied, it is logical that the diameter of the fuel flow passageway be increased. However, it has been found that atomization of the fuel becomes increasingly difficult as the fuel passageway diameter is increased due to the inability to effectively penetrate and disrupt the central core of the liquid fuel stream with atomizing fluid. Ac-

cordingly, it is an object of the present invention to provide a modified atomizer whereby more effective penetration and disruption of the fuel stream core isrealized so that atomization is improved and/or the maximum =be effectively increased.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

In the drawings:

FIG; 1 is an elevational view, partly in section, of a vapor generating unit and furnace incorporating the burner of the present invention;

FIG. 2 is an enlarged sectional elevation of the liquid fuel burner;

FIG. 3 is a further enlarged longitudinal partial sectional view of the atomizer assembly of the liquid fuel burner;

FIG. 4 is a sectional view taken along line 44 of FIG.

, 3; and

2 FIG. 5 is a sectional view taken along line 5-5 of FIG. 3.

In the illustrated embodiment of the invention the burner is associated with a furnace 10 constructed and arranged for the combustion of a pulp residual liquor resulting from the digestion of cellulosic material in a relatively pure magnesium base sulphite cooking liquor. The residual liquor from this process is particularly erosive to burner atomizer parts and the usual type of steam atomizing burner has had a useful life measured in hours, and when constructed with expensive alloy parts a life not exceeding a few days at best. In this process the residual liquor is preferably 'burned in suspension. A high degree of spray atomization of the liquor and thorough mixing with combustion air is desirable to complete the combustion process and to cause the conversion of the magnesium sulfate in the liquor to a reactive form of magnesium oxide.

Referring to FIG. 1 the furnace 10 is substantially completely lined with high alumina refractory materials. High combustion temperatures are attained in this furnace. As shown, the rear wall 11 of the furnace consists of refractory blocks supported upon fluid cooled tubes 12 with a gas outlet 13 in the rear wall positioned upwardly adjacent the furnace floor 14. The furnace floor is formed of hollow tile 15 covered with high aluminum refractories, with preheated air delivered to the front portion of the floor through a valved duct 17, passed through the hollow tiles and discharged into the upflow open pass 18 of an associated vapor generator 20.

Residual liquor at a concentration of 50 to 60% solids is delivered to the upper portion of the furnace 10 through burner ports 16 positioned in opposite side walls of the furnace. The residual liquor is atomized by the burners, as hereinafter described, mixed with air, and the com-v bustible matter therein burned in suspension within thefurnace 10. Leaving the furnace outlet 13 the combustion gases generated in the furnace are passed through a series of fluid cooled upright open gas passes 18, 21 and 22 and pass through the convection pass 23 of the vapor generator. The gases then pass through an air heater 24, and are subsequently treated' in a supplementary system for the separation of the MgO solids in the gases and for the absorption of sulphur oxides in a wash liquid (not shown).

Advantageously the combustion air used in the furnace 10 is preheated to assist in an efficient and rapid combustion of the organic matter in the residual liquor. Air from the forced draft fan 25 is passed through the air heater 24 into a duct 26 for distribution to the furnace 10 through the valved branch duct connections 17, 27 and 28. The duct connections 28 extend upwardly on opposite sides of the furnace to open into a horizontally disposed distributing manifold 30 which is provided with a series of discharge pipes 31 extending between the tubes forming the roof of the gas passes 18 and 21 and arranged to discharge into the gas stream passing into the gas pass 21. The duct connections 27 likewise extend from the duct 26 to an enclosed housing 33 surrounding the burner ports on the opposite sides of the furnace.

Each of the burner ports 16 is provided with an air register and a liquid fuel atomizer assembly, whereby the fuel and air are delivered to the furnace 10 through each port. A vertical elevation (taken along the centerline of a burner port and in a plane perpendicular to the side wall of the furnace) of an individual air register and atomizer assembly is shown in FIG. 2. A ring member 34 having an inwardly tapering surface, and provided with a circumferentially arranged series of air directing 0 vanes 35, is fastened to the casing 36 enclosing the rehousing 33 is spaced from and generally parallel to the casing 36, and is connected thereto by a series of brackets 38 arranged about the periphery of the burner. A series of radially arranged air directing blades 40, each mounted on an individual axis, are interconected by linkage for simultaneous adjustment from a common exterior lever 39. The blades can be closed to substantially cut off air flow to the furnace, and can be adjustably opened to regulate the quantity of air passing therethrough. Thus in all open positions, the air stream passing between adjacent blades 40 is given a swirling motion.

In addition, a slotted diffusion cone 41 is positioned in the burner port 16 by the barrel 42 of the liquid fuel burner. The combination of the blades 40 and the diffusion cone 41 directs the flow of combustion air through the port in a whirling movement of the air mass surrounding and impinging upon a fine spray of liquor discharged from the atomizer tip 43 of the burner. In the embodiment of FIG. 2, the barrel 42 is formed of an elongated tubular member projecting through a cover plate 44 which is bolted to the plate 37. The barrel is centered so as to be substantially coaxial with respect to the member 34, and is exteriorly provided with the conventional coupling provisions for the separate admission of both liquid fuel and atomizing fluid, as indicated generally at 45. The atomizing fluid may be steam, or other gaseous or vapor fluid.

Coaxially within the barrel 42 is the atomizer assembly, the tip 43 of which is shown in detail in FIGS. 3, 4 and and includes inner and outer tubes 46 and 47 respectively coaxially arranged to-define separate inner and outer passageways 48 and 50 for the respective flow of liquid fuel and the atomizing fluid. A sprayer head 51 is threaded to the end portion of the tube 46 and is provided with a flanged end portion 52 circumferentially engaging a shoulder 53 formed interiorly in the end portion of the tube 47. The head 51 serves to center and to maintain the desired end spacing relationship between the tubes 46 and 47. A series of cir-cumferentially spaced ports 55 are drilled in the flanged end portion 52 to provide flow communication for the atomizing fluid between the passageway 50 and an atomizing plate 56.

The atomizing plate 56 and a tip member 57 are assembled in coaxial abutting relationship to the head 51, and are maintained in position by a cap member 58 which is threaded onto the end of the outer tube 47. An inwardly extending flange 60 of the cap member 58 engages a correspondingly recessed outer portion of the tip 57 to maintain coaxial alignment of the assembly.

The upstream face of the atomizing plate 56, i.e., the face abutting the flanged portion 52 of head 51, is formed with an open-sided annular groove or chamber 61 which is in communication with the ports 55 of the flanged end portion 52. Another open-sided annular groove 62 is similarly formed in the opposite (downstream) face of the atomizing plate 56, i.e., the face abutting with the tip member 57. A series of c-ircumferentially spaced openings 63 extend between the grooves 61 and 62 to provide for the flow of atomizing fluid to the groove 62.

The atomizing plate 56 is formed with a central bore or throat 64 having a diameter substantially equal to the diameter of the passage 48 so that the liquid flow path through the atomizer tip 43 -is substantially unobstructed. A plurality of circumferentially spaced fluid passages 62A are formed in the downstream face of the plate 56, extending from the groove 62 inwardly and through the confining wall of the throat 64. The passages 62A are arranged to discharge streams of atomizing fluid into the throat 64 substantially tangentially thereto. Another set of circumferentially arranged fluid passages 61A are formed in the upstream face of the atomizing plate 56 and extend from the groove 61 inwardly to the throat 64, the passages 61A being arranged to discharge streams of atomizing fluid into the throat 64 in directions more nearly radial than the passages 62A. Preferably, the passages 61A and 62A are arranged to direct their streams of fluid tangentially with respect to imaginary circles of lesser diameter than the diameter of the throat 64. It should also be noted that the discharge ends of the passages 61A and 62A are alternately spaced about the periphery of the throat 64 to effect maximum disruption of the liquid stream.

In the embodiment shown, for ease of fabrication, the passages 61A and 62A are rectangular in cross section; however, it will be understood that the cross-sectional shape can be varied within the scope of the invention. Moreover, it should be understood that the number and size of the passages 61A and 62A can be varied within the scope of the invention, depending on the pressure of the atomizing fluid and the desired degree of atomization.

The tip member 57 is provided with an outwardly flaring conical surface 66 diverging from the periphery of the throat 64 at an included angle of approximately 25- 30 to control the rate of expansion of the liquid fuel as it leaves the burner tip 43.

Operation In the operation of the atomizer, as the liquid fuel flows from the passageway 48 into the throat 64 of the atomizing plate 56, it impinges with streams of atomizing fluid discharged from the passages 61A, the atomizing fluid being directed primarily to penetrate and disrupt the central core of the fuel stream. Immediately thereafter and independently thereof, the fuel stream is again impacted with atomizing fluid discharged from the passages 62A, which passages are arranged to supplement the disrupting effect of the first atomizing fluid streams and to impart a whirling motion to the fuel stream. The fuel stream, having thus encountered two successive and independent stages of atomization arranged to disrupt the fuel stream and impart to it a whirling motion in progressive steps, is then subjected to controlled expansion in the tip member 57 prior to discharge into the furnace.

While in accordance with the provisions of the statutes I have illustrated and described herein a specific embodiment of the invention, those skilled in the art will understand that changes may be made in the form of the invention covered by the claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of the other features.

What is claimed is:

1. As an article of manufacture, a sprayer plate comprising a disk having an axial bore of substantially uniform diameter for passage of a fibrous material-containing liquor therethr-ough, means forming a first annular groove in one face of the sprayer plate radially spaced from and surrounding said bore, means forming a plurality of first circumferentially spaced fluid flow passages disposed in a common plane and extending inwardly from said first annular groove to said bore, said first passages being arranged to open into said bore in a direction tangential to a small diameter circle within said bore to act upon said fibrous material-containing liquor, means forming a second annular groove in the opposite face of the sprayer plate radially spaced from and surrounding said bore, passage means interconnecting said first and second annular grooves, and means forming a plurality of second circumferentially spaced fluid flow passages disposed in a common plane parallel with and spaced from the plane of said first passages in the axial direction of the bore and leading from said second annular groove to said bore, said second passages being arranged to open into said bore in directions more nearly tangential than said first passages and directed to be tangent to a circle of greater diameter than said small diameter circle and less than the diameter of the bore.

2. A sprayer plate according to claim 1 wherein each of the said first and second passages discharge into the said bore in the same direction of whirl.

3. A liquid fuel burner comprising walls defining coaxial passageways for a fibrous material-containing liquor type of fuel and a highly expansible atomizing fluid respectively, a sprayer plate operatively connected to said passageways and having a central bore of substantially uniform diameter therethrough forming a continuation of the liquid fuel passageway, means forming a first annular groove in one face of the sprayer plate radially spaced from and surrounding said bore and in communication with said atomizing fluid passageway, means forming a plurality of first circumferentially spaced fluid flow passages disposed in a common plane and leading from said first annular groove to said bore, said first passages being arranged to discharge streams of said highly expansible fluid into said bore substantially tangentially thereto, means forming a second annular groove in the opposite face of the sprayer plate radially spaced from and surrounding said bore and in communication with said atomizing fluid passageway, means forming a plurality of openings interconnecting said first and second annular grooves, and means forming a plurality of second circumferentially spaced fluid flow passages disposed in a common plane spaced from the plane of said first passages in the axial direction of the bore and leading from said second annular groove to said bore, said second passages being arranged to discharge streams of said highly expansible fluid into said bo-re to act upon said fibrous material-containing liquor in directions more near 1y radial than said first passages to penetrate and atomize the central core of the fuel flowing through said bore.

4. A liquid fuel burner according to claim 3 wherein the first passages open into the bore at a location downstreamfuel flow-wise of the location where the second passages open into the bore.

References Cited UNITED STATES PATENTS 1,451,063 4/ 1923 Anthony 239427.3 X 1,736,768 11/1929 Boynton 239405 X 1,789,977 1/ 1931 Hopkins 239402 2,812,212 11/1957 Rogers et a1 239434 X 3,070,317 12/1962 Hunter et al. 239402 FOREIGN PATENTS 166,466 8/1950 Austria.

M. HENSON WOOD, JR., Primary Examiner.

VAN C. WILKS, Assistant Examiner.

Claims (1)

1. AS AN ARTICLE OF MANUFACTURE, A SPRAYER PLATE COMPRISING A DISK HAVING AN AXIAL BORE OF SUBSTANTIALLY UNIFORM DIAMETER FOR PASSAGE OF A FIBROUS MATERIAL-CONTINING LIQUOR THERETHROUGH, MEANS FORMING A FIRST ANNULAR GROOVE IN ONE FACE OF THE SPRAYER PLATE RADIALLY SPACED FROM AND SURROUNDING SAID BORE, MEANS FORMING A PLURALITY OF FIRST CIRCUMFERENTIALLY SPACED FLUID FLOW PASSAGES DISPOSED IN A COMMON PLANE AND EXTENDING INWARDLY FROM SAID FIRST ANNULAR GROOVE TO SAID BORE, SAI FIRST PASSAGES BEING ARRANGED TO OPEN INTO SAID BORE IN A DIRECTION TANGENTIAL TO A SMALL DIAMETER CIRCLE WITHIN SAID BORE TO ACT UPON SAID FIBROUS MATERIAL-CONTAINING LIQUOR, MEANS FORMING A SECOND ANNULAR GROOVE IN THE OPPOSITE FACE OF THE SPRAYER PLATE RADIALLY SPACED FROM AND SOURROUNDING SAID BORE, PASSAGE MEANS INTERCONNECTING SAID FIRST AND SECOND ANNULAR GROOVES, AND MEANS FORMING A PLURALITY OF SECOND CIRCUMFERENTIALLY SPACED FLUID FLOW PASSAGES DISPOSED IN A COMMON PLANE PARALLEL WITH AND SPACED FROM THE PLANE OF SAID FIRST PASSAGES IN THE AXIAL DIRECTION OF THE BORE AND LEADING FROM SAID SECOND ANNULAR GROOVE TO SAID BORE, SAID SECOND PASSAGES BEING ARRANGED TO OPEN INTO SAID BORE IN DIRECTIONS MORE NEARLY TANGENTIAL THAN SAID FIRST PASSAGES AND DIRECTED TO BE TANGENT TO A CIRCLE OF GREATER DIAMETER THAN SAID SMALL DIAMETER CIRCLE AND LESS THAN THE DIAMETER OF THE BORE.

Images