US2338623A - Burner structure - Google Patents

Description

INVENTOR Q N a V g V V &

\B 3 win? Marsha Crow? Jan. 4, 1944. J. M. CROWE BURNER STRUCTURE Filed Jan. 50,; 1941 Patented Jan. 4, 1944 UNITED STATES PATENT "OFFICE BURNER STRUCTURE John Marshall Crowe, Covlngton, Ky. Application January 30, 1941, Serial No. 378,666

. 4 Claims.

This invention relates to a burner structure,

and especially to one adapted for use in the smelting of metal in an open hearth furnace.

An object of the invention is to provide a burner of the character stated, in which means are incorporated for greatly increasing the emciency and the adaptability of the burner to conditions existing in smelting furnaces.

Another object of the invention is to provide a burner with novel features of construction to avoid clogging or obstructing of the nozzle by drippings from the furnace ceiling, and to increase the durability and efiiciency of the burner.

A further object of the invention is the realization of the foregoing advantages without resort to complex and expensive mechanisms.

These and other objects are attained by the means described herein and disclosed in the accompanying drawing; in which Fig. 1 is a perspective view of a burner embodying the invention.

Fig. 2 is an enlarged fragmental cross-sectional view showing the nose or forward end of the burner.

Fig. 3 is an enlarged fragmental cross-sectional view showing the rear end of the burner. v Fig. 4 is a cross-sectional view on a slightly reduced scale, taken transversely through the trunnion block 6 of Fig. 1. I

In the open hearth process of smelting, much difliculty has been encountered in the past, in an effort to keep fuel oil burners in operating condition. The major portion of the length of the burner barrel ordinarily is projected well into the combustion chamber of the furnace and is there subjected to intense heat. The intense heat of the combustion chamber will, at times,

fuse and melt the ceiling and walls of the furnace, thereby causing drippings of fused brick and clay to fall and accumulate upon the nose of the burner. As the nose of the burner is relatively cool, the drippings will solidify and will in some instances close or partially close the nose of the burner, When this occurs, the flame of the burner becomes weakened and is diverted, resulting in seriously impairing the effectiveness of the flame. With the burner in such a condition, it is diiflcult to maintain the operating heat of the furnace, wherefore the burners must be periodically cleaned and serviced from time to time. The clogging of burners, moreover, interferes with the scheduled operation of the furnace, and thereby increases the steel production cost. The nose of the improved burner of this invention has been designed to eliminate the dimculties heretofore encountered as the result of drippings reaching the nose of the burner.

As most burners of the type used in the smelting of iron are equipped with a water cooling system, there is presented a problem of keeping the burner constituents from separating from one another on account of unequal expansion and contraction of the parts. This problem has been met and eliminated in the burner structure of the present invention. By means of a cooling system which is incorporated in the burner herein disclosed, there is avoided the danger of stoppages such as might result in burning away the entire barrel of the burner. A rocker mechanism incorporating the hand wheel 8 and screw l5, ensures perfect control of the burner, and eliminates the possibility of breakage such as might disable the burner and remove it temporarily from service.

With reference to the accompanying drawing, the character 2 indicates the barrel of the burner having a special nose or nozzle 3. The rear end of the barrel has a burner end cap or bonnet l, to which a supply pipe for gas is connected. The gas supply pipe is indicated at 5.

At a point intermediate the front and rear ends of the burner barrel, a trunnion block 6 is fixed in any suitable manner, such as by welding, and this trunnion block carries a pair of laterally extending pins 1 which are journaled in the brackets 8 that extend upwardly from the burner carriage indicated at 9. As suggested by the drawing, the burner carriage conveniently may be formed from an angle iron or other structural member, suitably reinforced by triangular gussets such as are indicated by the characters ill. By preference, the carriage is to be bolted to a wall of the furnace. For this purpose it may be furnished with a series of elongated bolt receiving apertures l2. Intermediate the ends of the carriage, a base plate 13 may be furnished for reasons to be explained. As will be understood, the carriage is to be mounted horizontally across an opening in the furnace wall, with the barrel of the burner projected through the opening and directed toward the crucible. That part of the burner disposed rearwardly of the carriage 9 is located exteriorly of the furnace and is normally accessible to the furnace tender.

Between the trunnion block 6 and the rear end of the burner, the barrel carries a fixed screw hanger, indicated at I4, and to this hanger there is pivoted the upper end of a screw l5 which forms part of the elevating and lowering mechanism for the burner. In the preferred construction, the upper end of the screw carries a pivot block l5, which is fixed relativeto the screw, and through which extends a pin I! of the hanger. Although the screw I5 is thereby restrained from axial rotation, it may nevertheless swing or pivot relative to the pin II. A hand wheel or other operator I 8 is operatively related to the screw and may be manipulated for rocking the barrel of the burner about its trunnion I, thereby enabling the furnace tender to properly direct the flame of the burner.

Other essential parts of the burner structure are the atomizer l9, the fuel feed pipe 20, the high pressure steam pipe 2|, the cooling water feed pipe 22, and the cooling water discharge pipe 23. An important constituent of the burner structure is the blow-01f cook 24', which may be connected to the water jacket of the burner by means of a section of pipe or conduit 25. As previously stated, a supply pipe 5 for gas under pressure is connected with the burner end cap or bonnet 4. Fuel pipe conveys fuel oil, tar, or pitch to the atomizer l9, wherein the fuel meets steam under high pressure and is thereby conditioned for combustion at the nose of the burner.

For a full disclosure of the interior of the burner, reference may be had to Figs. 2 and 3 of the drawing. Fig. 2 shows the nozzle end of the barrel, whereas Fig. 3 shows the rear end thereof, including the end cap or bonnet 4. As will be evident, the barrel comprises an outer tube 38 and an inner tube 39, which together form an annular space or water jacket indicated at 40. The water' jacket extends throughout substantially the full length of the burner barrel. At the extreme forward end of the barrel, the nose portion 3 cooperates with the inner tube 39 for extending the water jacket to substantially the tip of the burner. The cylindrical nose portion 3 may be fixed to the outer tube 38 in any suitable manner, such as by means of welding at the location 4|. Where the cooling water outlet pipe 23 attaches to the water jacket, a very substantial joint may be formed by means of a weld 42. A similar weld 43 may be employed to join the blow-off pipe to the barrel, in communication with the rear portion of the water jacket, preferably at the under side of the barrel. The cooling water entry pipe 22, follows the length of the barrel exteriorly thereof, and enters the water jacket through an opening 44 in the nose part 3 where a substantial connection is made by means of the weld 45. As the cooling water enters the burner water jacket at the forward end, and is discharged at the rear end thereof, full advantage of the cooling function is gained.

The gas supply tube 39 which forms the inner wall of the water jacket is fixed and sealed to the forward end of the nose piece 3 by means of a built up weld 46, which weld also forms a special terminal lip as will be explained. An annular spacer 4'! loosely supported'within the tube 39 furnishes the necessary support for the inner fuel tube which is made up of the sections 48 and 49. The spacer is provided with a series of openings 50 to permit the flow of gas from the supply pipe 5. As willbe understood, gas from the supply pipe 5 surrounds the tube 48-49, and meets the atomized oil, tar, or pitch at the extreme forward end 5| of tube 49. By preference the inner fuel tube 45-49, the gas tube 39, and the tube which forms the outer wall of the burner, are substantially concentric as shown.

Referringnow to Fig. 3, the character 52 indicates a gland ring or bushing-inserted and fixed, in the rear end of. the outermost tube '39.

'Ihisring may be welded to'the tube,; as I at 53. By means of threads54'on the ring, the 5 7 bonnet 4 may be attached tothe barrelof the An inwardly directed flange 55 on the ring provides an opening for the receptioncf' burner.

tube 39 and centers it relative to the outermost tube of the barrel. quantity of packing material 55 iscompacted,

and kept in a state of compression by means of a packing-ring 51. The. packing ring has a head 58 externally threaded for engaging cooperativeinternal threads on the gland ring or bushing 52, to compress the packing. The innermost fuel tube 49 will be seen to extend through the central opening 59 of the packing ring 5'1, leaving sufficient space for the gas supply from pipe 5 to pass on toward the nose of the burner shown in Fig. 2.

From the foregoing, it will be understood that the packing 55 not only seals the rear end of the water jacket, but also permits the tube 39 to expand and contract longitudinally independently of expansion and contraction of the barrelexterior, and of the innermost fuel tube 45-49. By providing for independent elongation of the several tubes which constitutes the burner, all liability of the burner elements to fracture and separate is effectively avoided. A burner barrel assembled in the manner described, will be free from leakage of gas and cooling water, and will accordingly render highly satisfactory and trouble free service. Under no circumstances will the gas tube 39 pull away from its welded connection with the nose of the burner at the annular connection indicated at 49, nor will extreme temperature differentials act to strain or rupture the joint'at 4| and 53 of the burner barrel.

As shown in Fig, 3, the inner fuel tube 49 extends from the rear of the bonnet 4 through a tightly fitted plug 59 having a screw threaded connection 5| with the open rear end of the bonnet. The atomizer I9 is connected to the free end of the inner fuel tube, as illustrated by Fig. 1.,

Referring now to Fig. 2, it should be observed that the annular weld 45 which Joins the nose 3 to the forward end of gas tube 39, is of a peculiar and definite shape and'is, moreover, constituted of an alloy which will withstand extremely high temperatures. To this end, the weld may be of fines the outer limits of the tip, andforinsan annular outer, ledge makinga sharp angle' with" the forward edge 55o! the'tip. The curved'slope v 61 at the forward-end of nose piece; meetsiythe and is thickened preferably as shown:

ledge or concavity 65 as a continuation'thereof The outer annular concaved surface 55-;51 1 may intercept drippings of fused clay and the,

Behind the flange55, a

like melted from the furnace ceiling, and will divert such drippings to one side or the other of a vertical plane intersecting the center-line of the burner barrel. The drippings while in the fluid state, will run about the outside periphery of the tip, rather than forwardly over the face following the inner concave area 64, which will instantly shear off and dislodge the drippings, thereby keeping the nozzle clear for continued operation of the burner.

The tip may be considered a form of snout projected forwardly and terminating as an annular wall 6i having concentric inner and outer sharp edges. The snout tapers down gradually to the width of the annular wall 66, with the tapers formed arcuately by preference, and meeting said wall substantially at right angles. The curvatures of the surfaces 65 and 64 are to be noted particularly and especially that of the outer ledge, because it is the outer ledge configuration that thins or sheets out any thick or heavy intercepted masses of drippings before such drippin s can reach the burner opening. Properly thinned and thereby structurally weakened drippings, are easily cut away and dislodged by the pressure of gases emanating from the front of the burner and sweeping the concave annular surface it. Unless the drippings are so thinned or sheeted, they might overhang the open end of the burner as a tenacious mass, and there solidify to accumulate additional drippings which promptly would clog the burner.

With reference to the perforate spacer 41, it may be stated that this element may have a pressed fit or a threaded connection with the fuel tube sections 48 and 49, as desired. As an alternative construction, said fuel tube may be furnished in a single piece rather than in sections.

For the proper operation of the burner, it is necessary that the fuel be conditioned in such manner as to avoid ejection of globules or coherent masses of fuel at the burner tip. For this purpose, any efficient form of atomizer may be employed, as indicated at [9. The steam pipe 21 communicates with the pressure chamber of the atomizer, and oil is fed thereto by the pipe 20.

As another feature of the burner construction, means may be provided for imparting to the vout- -er tube 38 of the barrel, the supportive rigidity of the inner tubular member 39 which, in practice, is cooler and less likely to deform than the outer tube 38 when subjected to very intense heat such as might be encountered in the event of a failure or serious reduction of cooling water in chamber l0. Under extreme conditions such as are referred to, the outer tube may lose some of its ability to support its forward end, but the inner tube 39 will retain its strength and rigidity for a longer period of time because of the fact that it is kept relatively cool by the gas which enters by way of the supply pipe 5. With the object of most effectively overcoming a possible sagging tendency of the barrel, a suitable stool or prop structure indicated at 9292--82, is interposed between the tubes 38 and 39 at a properlocation within the barrel to keep the forward end of the inner tube 39 boosted up in support of the tip end of the outer tube. The structure 92,92-92 may convenientlyconsist of several lengths of metallic bars edge-abutted and Welded as at 93, or otherwise secured, to the outer wall of tube 39 so as to extend radially outwardly therefrom to contact the inner wall of tube 38 directly above the water supply pipe 22. The bars 92 may be a foot, more or less, in length and will preferably be disposed within a portion of the barrel which is always comparatively cool, that is, in the region at either side of the trunnion block 6. The bars are not to b secured to the inside of tube 38, but should be longitudinally slidable relative thereto so as not to interfere with the normal expansion differential of the tubes as permitted by the packed, joint at 56. A sufiicient number ofbars may be provided as determined by the various factors of weight, heat, and location, and as will be understood, none of such bars need be located above the center-line of the barrel. Moreover, they do not interfere with the free circulation of cooling water through the jacket or chamber 40. The structural strength of the burner, of course, is greatly enhanced by means of a stool or prop structure having the characteristics and functionalattributes herein related.

What is claimed is:

1. In a burner of the class used in metal treating furnaces in which fused material drips from an interior wall, the combination which comprises an elongated barrel including an apertured nozzle, pressure means for ejecting a fuel from the nozzle, 9. heat resistant tip on the nozzle including a concaved annular and forwardly extended outer ledge surface formed on a shortradius arc, and a front annular wall on the tip meeting said concaved surface where said concave surface approaches parallelism with the barrel axis, for diverting furnace drippings from the nozzle aperture and precluding formation of accumulated drippings as a mass over the nozzle aperture.

2. In a burner of the class used in metal treating furnaces in which fused material drips from an interior wall, the combination which comprises an elongated barrel including an apertured nozzle, pressure means for ejecting a fuel from the nozzle, and a tip on the nozzle including a concaved annular and forwardly extended outer surface and a. front annular wall on the tip meeting said concaved surface at a sharp angle, where said concaved surface approaches parallelism with the barrel axis, for diverting furnace drippings from the nozzle aperture and precluding formation ,of accumulated drippings as a mass over the nozzle aperture, and an inner annular surface on the tip angularly meeting said front annular .wall to provide an outwardly flared exit to direct a portion of the fuel under pressure laterally outwardly past said front annular wall with a forceful cut-off action.

3. In a burner of the class used in metal treating furnaces in which fused material drips from an interior wall, the combination which comprises an elongated barrel including an apertured nozzle, means for pressure feeding a, fuel through the barrel and out of the nozzle aperture, and a snout about the nozzle for sheeting fused furnace drippings falling thereon toward the nozzle aperture, said snout comprising a reduced exterior end portion on the nozzle tapering toward the barrel axis for a distance, and then curving forwardly along a short-radius arc toward parallelism with the barrel axis, and a front annular wall on the snout having a substantially flat forward face meeting the forward curve at approximate perpendicularity where the curve approaches parallelism with the barrel axis, and an inner annular concavity within the snout, formed on a short-radius arc to provide an outwardly flared exit for directing a portion of the fuel under pressure laterally outwardly past said front annular wall of the snout with a. cut-ofl action, said concavity terminating in said front annular wall as a sharp interior cut-off edge.

4. In a burner of the class used in metal treating furnaces in which fused material drips from an interior wall, the combination which comprises an elongated barrel including an apertured nozzle element projecting forwardly of the barrel in fixed relationship thereto, said nozzl element having at the aperture a reduced front end portion tapered inwardly and forwardly, and terminating in a reentrant wall, an inner water Jacket tube having a forward end received in the nozzle element aperture at said reentrant wall, and a welded tip joining the end of the jacket tube to the reentrant wall of the male element, said tip comprising a portion forming a continuation oi the tapered end 01' the nozzle element, and curved forwardly along a short-radius arc toward parallelism with the barrel axis, a front annular wall on the tip having a substantially fiat forward face normal to the barrel axis and meeting the forward curve at approximate perpendicularity where the curve approaches parallelism with said axis, an inner annular wall on the tip flaring outwardly and forwardly to direct fuel under pressure laterally outwardly for cutting oil? furnace drippings sheeted by the exterior curvature of the tip, and an inwardly directed shallow annular flange on the tip forming a seal and anchor abutment for the inner jacket tube.

JOHN MARSHALL CROWE.

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