US3752402A

US3752402A - Fluid injection lance and nozzle means therefor

Info

Publication number: US3752402A
Application number: US00135269A
Authority: US
Inventors: H Marioneaux
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-04-19
Filing date: 1971-04-19
Publication date: 1973-08-14
Anticipated expiration: 1990-08-14

Abstract

A nozzle attachable to a lance shank to provide an oxygen injection lance for the delivery of large quantities of oxygen to the melt in a steelmaking furnace. The nozzle is bell-shaped and has nine sectorial passageways running through it from top to bottom. The sectorial passageways are equiangularly spaced about the nozzle axis and separated by radial webs. Each of the webs has a slotted cavity, enclosed at the top and bottom, penetrating the body of the nozzle from the outside in, and all of the slotted cavities converge at the axial center of the nozzle to provide access from one to the other at this juncture. The sectorial passageways have straight-walled upper portions, but flare radially outwardly in their lower portions. When the lance is in operation, oxygen passes downwardly through the lance shank and from there into the sectorial passageways of the nozzle. Because of their flaring lower portions, the sectorial passageways deliver the oxygen in an expanding pattern for widespread and uniform coverage of the melt in the furnace. Coolant is circulated through the slotted cavities in the radial webs of the nozzle when the injection lance is in use.

Description

United States atent n91 Marioneaux Aug. 14, 1973 FLUID INJECTION LANCE AND NOZZLE MEANS THEREFOR [76] Inventor: Harry Marioneaux, 2934 Rulrdoix Blvd, Riverside, Calif. 92509 Filed: Apr. 19, 1971 Appl. No.: 135,269

[ 56] References Cited UNITED STATES PATENTS 5/1967 Smith et a1. 266/34 L 3/1969 Berry... 239/1323 X 9/1957 Gehring 239/1323 2/1967 Hutton 239/1323 5/1967 Vonnemann 239/1323 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Michael Mar Attorney-John 1-1. Crowe and Peter H. Firsht [5 7] ABSTRACT A nozzle attachable to a lance shank to provide an oxygen injection lance for the delivery of large quantities of oxygen to the melt in a steelmaking furnace. The nozzle is bell-shaped and has nine sectorial passageways running through it from top to bottom. The sectorial passageways are equiangularly spaced about the nozzle axis and separated by radial webs. Each of the webs has a slotted cavity, enclosed at the top and bottom, penetrating the body of the nozzle from the outside in, and all of the slotted cavities converge at the axial center of the nozzle to provide access from one to the other at this juncture. The sectorial passageways have straight-walled upper portions, but flare radially outwardly in their lower portions.

When the lance is in operation, oxygen passes downwardly through the lance shank and from there into the sectorial passageways of the nozzle. Because of their flaring lower portions, the sectorial passageways deliver the oxygen in an expanding pattern for widespread and uniform coverage of the melt inthe furnace. Coolant is circulated through the slotted cavities in the radial webs of the nozzle when the injection lance is in use.

10 Claims, 4 Drawing Figures Patented Aug. 14, 1973 FIG. 2.

INVENTOR. AMP/P) J/flP/d/ViAZ/X IGE/VT FIG. 3.

BACKGROUND OF THE INVENTION This invention relates generally to an improved type of injection lance for use above the melt in a metallurgical furnace, and more particularly to such a lance having a nozzle of special suitability for directing oxygen onto the melt in a steelmaking furnace.

The technique of blowing high velocity streams of oxygen through injection lances onto baths of molten metal, for the oxidation and removal of impurities, has been employed for a number of years in the steelmaking industry. Such an injection lance typically comprises an elongate shank, 30 or so feet in length, having a specially designed nozzle fixedly secured to its lower end. This shank is commonly formed from three concentric pipes and is supported vertically over the melt in a steel furnace with its lower nozzle end disposed generally from 60 to 72 inches above the melt. The concentric arrangement of pipes provides three fluid flow paths, a central one of round cross section and two concentric flow'paths arranged annularly aroundthe central one. The central passageway through the shank is used for oxygen, and the two annular passageways for incoming and outgoing coolant (typically water), the coolant being pumped downwardly, through the inner pathway, into hollows in the nozzle, from whence it is routed upwardly, through the outer annular pathway, away from the furnace. Although many lance nozzle designs have been proposed, the typical nozzle in present day use is characterized by one or more round passageways for the ejection of oxygen from the lance, and surrounding hollow spaces for the circulation of coolant around the walls of the oxygen passageways. A very common type of nozzle in everyday usage has three oxygen conduits diverging outwardly from their upper ends to their lower, exit, openings (and sometimes a straight center conduit as well), to permit widercoverage of the surface of the melt in the furnace than would be possible with a single, downwardly directed stream of oxygen from the lance.

As will be appreciated, the use environment of an oxygen lance nozzle is extremely harsh. For this reason, lance nozzles have short lives and must be frequently replaced, thus adding to the expense of the operation. The high furnace temperature, for example, is hard on lance nozzles, since it causes them to soften and deform. The primary purpose of the coolant circulating through the lance and nozzle is to keep the nozzle temperature down to a sufficient extent to minimize this softening effect. Experience has shown, however,.that the proper use of coolant'in the nozzle, to achieve this purpose, is not easy. For example, those prior art lance nozzles with round oxygen channels and surrounding spaces for coolant have been found to work imperfectly in that dead coolant zones are created with consequent loss of heat transfer capacity in the system. Attempts have been made 'to eliminate, or reduce, these dead zones by slowing the rate of coolant velocity through the nozzle, but this also results in reduced cooling effect, and is thus not a very'satisfactory solution to the problem.

But high temperature is not the only thing that contributes to short lance nozzle lives. Since, as indicated above, oxygen injection lances presently in use have nozzles which direct one or several, typically three or four, streams of oxygen (of generally round cross section) downwardly onto furnace melts, there is a great deal of turbulence in the area between the nozzle and the surface of the melt. This turbulence is caused in part by the unevenness of surface contactof the melt by the injected oxygen, the oxygen, for example, contacting the melt at relatively high pressures in the stream areas, whereas the meltsurface areas between these stream impact zones are subjected to relatively low, or no, oxygen pressure.

Where one or more high velocity streams of gas impact the surface of a liquid body, splashing of the liquid is to be expected. In the case of oxygen ejection from a lance nozzle onto a body of molten material in a steel furnace, the splashing effect results in the casting of droplets of material from the melt upwardly and into contact with the nozzle, to the detriment of the latter. Moreover, where the nozzle ejects a plurality of oxygen streams, such as three or four such streams, a low pressure zone is created in the space between the streams, into which furnace gases, particles from the bath, etc., rush. This inrush of gases and particles results in much turbulence, distortion of the oxygen streams, the fusion of furnace gases into the oxygen, and dilution of the effectiveness ofthe oxygen. The stormy turbulence in the furnace has been found to create pressure oscillations in the oxygen streams, thereby contributing to slopping, sparking and splashing of the bath toa greater 'extent than would otherwise be the case. This excessive sparking, splashing, etc., of course, subjects the nozzle to increased bombardment by particles from the bath, and thereby intensifies the damaging effect of such particles. Damage to the interior surfaces of the furnace withinbombardment range of the particles also results from excessive turbulence, and, consequent oscillation of the oxygen streamsfin the furnace atmosphere. Where pieces of scrap metal, some of substantial size, are present in the furnace melt, as is often the case, severe damage can result from the turbulent conditions created by separate oxygen streams impacting the melt. It is not uncommon for chunks of scrap metal to be thrown into contact withthe lance and cause scarfing of its shank or nozzle. Such scarfing has been known to result in puncturing of the outer wall of the lance and consequent loss of coolant therefrom.

In addition to causing erosion and scarfing of the oxygen lance and furnace vessel walls as a result of the turbulent conditions resulting from the injection of separate streams of oxygen onto the melt in a steel furnace, this form of injection creates hot and cold. spots in the melt, and less than total coverage ofthe melt surface by the oxygen, with consequent wastage of the latter. Where a stream of oxygen impacts the melt, there is high localized heating, and even boiling, and where the stream is inclined toward the outer edge of the melt there is localized wear of the furnace refractories. In the cooler parts of the melt surface, between the jet stream impact areas, there is greatly reduced oxidation ofimpurities in the bath. These impuritiesare ejected upwardly, as are the bath particles, and where they come into contact with the water-cooled lance they I tend to stick and cause skull buildup on the lance and nozzle. Such skull buildup is serious, adding greatly to the weight of the lance, and sometimes even causing it to fall into the melt. It is not uncommon, in this connection, for skull buildup to increase the diameter of a lance from 6 inches to 1% feet or more. Various attempts have been made to deal with this problem, including shooting the layers of skull with a rifle, vibrating the lance to shake the skull loose, etc., none with very satisfactory results.

From the foregoing, it will be apparent that oxygen injection lances commonly used today in steelmaking furnaces serve to create environmental conditions above furnace melts which result in severe damage to the lance nozzles and furnace refractories through the impact of debris from the bath; that such lances leave much to be desired in the way of heat transfer from the nozzle to the circulating coolant, with the result that the nozzles are softened and deformed; that the pattern of oxygen distribution over the melt surfaces results in localized heating (and sometimes damage to the furnace) and inefficient use of the oxygen; and that, as a result of this inefficient use of oxygen, the lances create conditions conducive to skull buildup on their outer surfaces and thereby sow the seeds of their own destruction. A lance nozzle designed to evenly distribute the oxygen passing therethrough over the surface of the melt,and capable of quickly and effectively transferring heat to a coolant liquid, would bring about the elimination, or substantial reduction, of all of the above-described difficulties attendant upon the use of present day lance nozzles.

SUMMARY OF THE INVENTION The lance nozzle of this invention, by virtue of a fundamental departure in design from conventional nozzles of present day type, serves to feed oxygen in a fairly even pattern of distribution over the surface of the melt in a steelmaking furnace, thus eliminating, or substantially reducing, turbulence in the furnace vessel (and consequent erosion and scarfing of the lance); localized heat damage to furnace walls; skull buildup on the lance; etc., such as result from the jetlike delivery of oxygen to the melt in one or more high velocity streams from these conventional nozzles. My new nozzle, moreover, has internal structural characteristics which permit the circulation of coolant around the walls of the oxygen passageways through the nozzle in such fashion as to assure a high degree of heat transfer from the nozzle to the coolant and thereby greatly reduce the possibility of softening and deformation of the nozzle in the hot furnace temperatures.

In its preferred form, the lance nozzle of this invention has a round flat top, a round flat bottom, and an intermediate body of generally bell-like shape. The nozzle is characterized by a plurality of (preferably nine) passageways of generally sectorial cross section which run from top to bottom therethrough. These passageways serve to direct the oxygen passing through the lance down onto the melt in the furnace. They have vertical walls for somewhat less than half of their lengths, below which they expand radially outwardly to termination at openings in the flat bottom of the nozzle with peripheral outer edges arranged in a circular pattern. The passageways are separated by radial webs extending vertically, from top to bottom, through the nozzle. The webs have slotted hollows, enclosed at their tops and bottoms, running from openings in the exterior wall of the nozzle body toward the axial center of the latter. These hollows provide flow paths for coolant through the nozzle body, and they communicate at the center of the nozzle to permit freeflow of the coolant through the nozzle body and assure extensive contact area between the coolant and internal nozzle surfaces for good heat transfer effectiveness.

The round, flat bottom of the lance nozzle merges, around its periphery, into a cylindrical collar spaced concentrically outwardly from the lower portion of the bell-like nozzle body. This body, in the preferred form of the nozzle, has three longitudinal ribs equiangularly positioned around its outer walliThe ribs are notched near their upper ends to provide seats for the lower rim of the middle or intermediate pipe of the belowdescribed lance shank.

The novel lance nozzle of this invention is adapted for permanent installation on the lower end of a lance shank formed from three round pipes of differing crosssectional diameter. The pipes are arranged concentrically with their bottom edges axially spaced to match the spacing between the top, the notches in the aforesaid ribs and the top of the cylindrical collar, of the nozzle, when the nozzle and lance shank are fitted together to form the lance. The innermost (smallest) pipe of the lance shank is welded in place around the top of the nozzle, and the outermost (largest) pipe welded to the top of the cylindrical collar, in the assembled lance. The middle pipe fits in the notches of the aforesaid ribs, but is not welded in position there. Leaving the lower end of this (middle) pipe unattached to the nozzle results in built-in tolerance to heat expansion, whereby the pipe is free to expand and contract without risk of damage to the lance structure.

The innermost pipe of the lance shank serves to convey oxygen from a manifold at the upper end of the shank to the lance nozzle, from whence the oxygen passes through the sectorial passageways and downwardly, in an expanding pattern of flow, onto the surface of the melt in a steel furnace. The two annular passageways defined by the concentric walls of the three lance shank pipes serve as coolant channels, the cool ant preferably passing downwardly through the inner annular passageway to the nozzle and upwardly, away from the nozzle, through the outer annular passageway.

Because of the cross-sectional shapes of the sectorial passageways in the lance nozzle, and the radially outwardly expanding configuration of the lower portions of these passageways, the oxygen passes out of the lower openings of the nozzle in a pattern of generally circular, outwardly expanding flow distribution. By the time the oxygen reaches the melt surface, it has spread to the point at which it covers substantially all of this surface. Moreover, the oxygen is fairly evenly distributed over the melt surface when it makes contact therewith, rather than having contrasting forms of high velocity jets and intermediate zones of low oxygen pressure and concentration. As a result of the pattern of oxygen delivery from my novel lance nozzle, the turbulence, melt splashing, scrap iron ejection, oxygen dilution, hot spot formation, oxygen stream oscillation, etc., effects of the normal delivery patterns of conventional lance nozzles of present day use, and the attendant nozzle erosion, lance scarfing, skull buildup, etc., disadvantages of these latter patterns, are virtually eliminated. Additionally, the sectorial oxygen passageways of my unique lance nozzle, by virtue of their substantially vertical upper segments, deliver oxygen streams of higher velocity from their inner, wedgeshaped areas than from their outer areas (where the oxygen is expanding radially outwardly because of the flaring outer walls of the passageways), thus providing good penetration, as well as wide surface coverage, of

the melt. This results in efficient utilization of the oxyen, and reduces the turbulence, and accompanying side effects, of the sort of penetration without blanket coverage achieved with presently conventional nozzles.

Finally,the unique design of my lance nozzle, with its honeycomb of slotted radial passageways and novel outer configuration cooperating to permit. good flow contact between the coolant and the walls surrounding the oxygen passageways,.makes for highly efficient heat transfer from the nozzle to the coolant, thereby minimizing. softening and consequent deformation of the nozzle in the hot furnace atmosphere. Insofar as I am presently aware, the preferred material of construction for the nozzle is substantially pure copper. Any material having the necessary physical and other, requirements for the purpose can, however, be employed in lieu of such pure copper, if desired. Examples of suitable materials of this type include copper alloys with hardeningadditives which do not unduly suppress the natural heat conductivity of copper, special ceramics tailored for use in oxygen lance environments, suitable metals with ceramic facings, etc.

It. is thus a principal object of this invention to provide lance nozzle means capable of introducing oxygen to the melt in a-steelmaking furnace in such a way as to provide relatively even distribution of the oxygen over the surface. of the melt and thereby insure the elimination of splashing, ejection of pieces of scrap iron from the melt, etc., and consequent reduction of erosion and scarfing damage to the lance shank and nozzle from the impactof particles of the melt and pieces of scrap metal tossed up in the absence of such even oxygen distribution over the melt surface (as in the oxygen jet distribution of presently conventional lance nozzles).

It is another object of the invention ti provide oxygen injection lance nozzle means eliminative of the contrasting zones of high oxygen jet velocity and relative quiescence therebetween with their accompanying conditions of turbulence, oxygen jet oscillation, oxygen dilution, inefficient oxygen usage, etc., and consequent skull buildup on the lance shank and nozzle.

It is yet another object of the invention to provide such. lance nozzle means which, by the prevention of hot spot formation from oxygen jet impingement on the outer extremities of the melt surface, serves to eliminate the possibility of damage to furnace refractories as a result of such impingement.

It is still av further object of the invention to furnish such lance nozzle means internally designed to permit the fast and effective removal of heat by a circulating coolant and thereby provide protection against the possibility of nozzle softening and deformation inhot furnace temperatures.

Other objects, features and'advantages of the invention will become apparent in the light of subsequent disclosures herein.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary elevation, partly in section, of the lower end of an oxygen injection lance with a lance nozzle of preferred design in accordance with this invention affixed, certain hidden features being shown by dashed lines.

DESCRIPTION OF THE PREFERRED EMBODIMENT Considering now the drawing in greater detail, there is shown generally at 10 a lance of preferred design in accordance with this invention. The nozzle is formed from pure copper (that is, copper of at least 99.0 percent purity, and preferably of 99.6 percent purity, with no trace of oxygen), ,for good heat conductivity, an improtant feature for reasons which will later become apparent. The nozzle could, as indicated above, however, be formed from a suitable material, or materials, other than pure copper, within the scope of my invention.

Lance nozzle 10 has a round, flat top part 12 (hereinafter top 12) and'a round, flat bottom part 14 (hereinafter bottom 14), integral with an intermediate, bellshaped body portion. 16 (hereinafter body 16). TIT-he nozzle is of substantially round cross section throughout, and its parts are arranged generally concentrically about a common axis. See FIGS. 3 and'4, which clearly illustrate this concentric relationship of parts. Passing fromv top to bottom through the nozzle are nine passageways 18 of sectorial cross-sectional shape. These passageways have vertical walls extending downwardly from their top openings, shown at 24, to a point at which their outer, arcuate walls begin to flare outwardly, indicated at 20 inFlG. I of the drawing, below which they expand radially outwardly to bottom openings of larger area than the top openings. These bottom openings are shown at 22 on the drawing. 1

The 'sectorial passageways 18 are separated by nine radial webs 26, running in the axial direction through the nozzle. The webs 26.have hollows 28 of slot-like cross section (hereinafter slotted hollows 28) running respectively therethrough from outer openings 29 around. the bell-shaped body 16 of the nozzle to termination at a central hollow 30 in said bell-shaped body. Both the slotted hollows 28' and the central hollow 30 are enclosed'at the top and bottom by top 12 and bottom 14, respectively, of the nozzle.

Merging with the peripheral edge of the round bottom 14 of nozzle 10, and extending cylindrically upwardly therefrom,.is a collar member 32 (hereinafter collar 32). Collar 32 is spaced radially outwardly from bell-shaped body 16 of the nozzle. This collar serves a purpose hereinafter discussed and, because of its radial spacing from.the bell-shaped body of the nozzle, provides a moat-like annular space around the nozzle body bounded by said body, bottom 14 and the collar itself. Fixedly secured to the outer wall surface of bell-shaped body 16 .in equiangularly spaced relationship around the nozzle axis are three ribs 60.'These ribs extend longitudinally upwardly along the wall of bell-shaped body 16 for a relatively short distance from the bottom of the aforesaid moat-like annular space around said body, and are each characterized by a notch 62 in its upper tip. The three notches 62 provide shoulders of equal height above bottom 14 of the nozzle for a purpose hereinafter disclosed. The round, flat top 12 of the nozzle has an annular shoulder 36 inset from its periphery, below which it is chamfered, as shown at 38, for a reason hereinafter appearing. The cylindrical collar 32, likewise, has an inset annular shoulder 44 around its upper edge and a thin-walled annular rim or lip 46 projecting upwardly from the shoulder around its inner periphery. Below the shoulder the collar is chamfered, as shown at 45, again for a reason hereinafter appearing.

Lance nozzle 10 is designed for permanent attachment to the lower end of an oxygen lance shank consisting of three concentrically arranged pipes, a fragmentary portion of such a shank being shown at 64 in FIG. 1 of the drawing. In the assembled lance, the inner of these pipes, shown at 48 in FIG. I, appropriately chamfered around its lower edge, rests on the annular shoulder 36 around the periphery of the round, flat top of the nozzle, in which position it is welded in place as indicated at 56. The middle pipe, shown at 50, is sufficiently longer than the inner pipe 48 to permit its lower edge to seat itself in the three notches 62 in the ribs 60, in the manner illustrated in FIG. 1. The middle pipe 50 merely rests in its seated position in the rib notches 62 and, since it is not welded to the notched ribs, has room for expansion with minimal risk of structural damage to the lance assembly. Preferably the inner pipe is a copper tube and the outer two pipes are made of steel. The outer of the three shank pipes, shown at 52, is chamfered around its lower edge similarly to the way inner pipe 48 is chamfered, and sized to permit seating of its lower edge on the annular shoulder 44 around the top of collar 32. The outer pipe is then welded in place, as illustrated at 58 in FIG. 1.

Lance shank 64 is about 30 feet long (the typical length of such shanks) and it is connected, at its upper end, to a manifold of conventional type, not necessary to describe in detail here, by means of which oxygen under pressure can be supplied to inner pipe 48. In a typical furnace operation, oxygen gas is fed into pipe 48 under sufficient pressure to give it a velocity equivalent to about Mach 1. The appropriate arrow in FIG. 1

indicates the flow path of this oxygen. When the oxygen reaches the flat top of lance nozzle 10, it passes into the sectorial passageways in the nozzle, as indicated by directional arrow means in FIG. 1, and is ejected downwardly therefrom onto the surface of the melt in a steelmaking furnace, some 5 or 6 feet therebelow. The upper, vertically walled portions of the sectorial passageways have cross-sectional areas which are, in sum, smaller than the cross-sectional area within the inner lance shank pipe 48. This reduction of flow area within the sectorial passageays causes the oxygen to increase in velocity as it enters the passageways from pipe 48. For example, if the total cross-sectional area within all of the passageways is equal to. half of the total flow area within pipe 48, the oxygen will double in velocity as it enters the nozzle, thus increasing its speed to the Mach 2 level from the Mach 1 level prevailing in the lance shank. This 1 to 2 ratio of cross-sectional flow areas is not critical, however, and the ratio can vary within relatively wide limits within the scope of my invention.

When the high velocity oxygen reaches the beginning of the outwardly expanding portions of the sectorial passageways, indicated at 20 in FIG. 1, the crosssectional flow area increases, and the streams of oxygen expand outwardly tovfill the additional space. At the exit openings of the passageways, in the bottom of the lance nozzle, there is a velocity gradient across the oxygen streams, from their inner to their outer boundaries. The inner segments of these streams are proceeding downwardly at higher velocities than their radially outwardly expanding outer segments, as a result of the flow momentum picked up by the oxygen in the upper, vertically walled portions of the sectorial passageways. The result is higher velocity impact of the melt around an inner core area, withgood penetration effect, and impact of lesser velocity fading radially outwardly from this core area to the periphery of the melt surface. The oxygen streams are, of course, expanding radially outwardly from the time they leave the nozzle until they impact the surface of the melt, at which time they have increased their area of coverage until they substantially blanket the melt surface, rather than boring into the melt with separate high velocity streams of relatively small cross-sectional area. This pattern of impact of the melt surface by the flowing oxygen keeps turbulence thereabove to a minimum, results in highly efficient utilization of the oxygen, prevents the formation of hot spots in the melt, etc., with all of the attendant advantages discussed at length above.

The annular space between the inner pipe 48 and middle pipe 50 of the lance shank, shown at 66 in FIG. 1, is for the inflow of coolant to the nozzle head. This coolant flows downwardly, as shown by directional arrow means in FIG. 1, until it reaches nozzle 10. When the coolant reaches the nozzle, it flows into the slotted hollows 28 in webs 26, in the manner indicated by the directional arrows on FIG. 4. The honeycomb of slotted hollows within the nozzle body, in mutual communication through the central hollow 30 of the bellshaped body of the nozzle, permits the coolant to flow around all of the outside surfaces of the sectorial oxygen passageways, and provides large areas of surface contact between the coolant and nozzle body. F urthermore, the intercommunicating relationship of all hollows within the nozzle body permits the coolant to flow throughout its honeycombed interior with a minimum of stagnation and a maximum of heat absorption from the highly conductive metal of the nozzle. The constant inflow of coolant forces the heated water within the nozzle structure down under the lower edge of the middle pipe 50 of the lance shank, from whence it flows upwardly, through the annular space (shown at 68 between that pipe (pipe 50) and outer pipe 52, in the direction of the outer arrows on FIG. 1.

It should be clear from the above that the unique interior structure of lance nozzle 10 provides a maze of through flow paths for the coolant, with no blind alleys" in which dead spots can exist, and, at the same time, makes large areas of heat transfer surface available within the nozzle. These twin advantages of the nozzle serve to very effectively protect it against overheating, and consequent softening and deformation, in hot furnace environments.

Lance nozzle 10 can, of course, vary in size, depending upon the surrounding circumstances. For example, it can be sized for mating interfit with the lower end of a lance shank made up of inner, middle and outer pipes of six-inch, eight-inch and ten-inch size, respectively. A lance nozzle of this size could be employed in presently existing furnace assemblies with little or no difficulty, since many lances now used in such assemblies have shanks of about ten-inch diameter. It will be observed, particularly in FIGS. 1 and 4, that the design of the bellshaped body 16 of lance nozzle is suchas to define surrounding side and arcuate walls for the nine sectorial passageways 18 through the nozzle. The sidewalls, shown at '70 on FIG. 4, and the arcuate walls, shown at 72,. are of'substantiallythe same thickness, preferably,

' l have discovered, about one-fourth-inch, except for Thenumber of sectorial passageways in thenozzle isvariable, depending upon such things asthe nozzle size, the ratio of cross-sectional nozzle flow area to the cross-sectional flow area in the oxygen conduit of the lance shank, etc. Where the nozzle is designed to fit a shank of theabove-mentioned size 10 inches in diameter),-n'ine passagewayswill normally suffice for the purpose. l have madea smaller nozzle, of 6#inch maximum diameter and adpated'for installation on the lower end of. a lance shank having an oxygen-conducting inner pipe of four-inch diameter, and here six sectorial passagewayswere found to be adequate. I prefer, as a rule of thumb, that the number of passageways bea multiple of three, such as, for example, six or nine.

Theangle of divergenceof the arcuate outer walls of the sectorial passageways, that is, the angle at which these walls fan out from the vertical below point (or, more properly, line) 20, shown on FIG. 1, is about 11 degrees. This angle can vary, however, depending upon the desired expansion pattern of'the oxygen streams leaving the lance nozzle. As will be apparent, the height of the nozzle above the furnace melt surface, the angle of divergence of the lower portions of the arcuate outer walls of its s'ectorial'passageways, the size of the nozzle, etc., can be mutually adjusted to achieve the desired coverage of the meltsurface'in any particular furnace. Van'es, or the equivalent, can, if desired, be built into the sectorial passageways of the nozzle to impart a swirling motion to the effluent oxygen streams, within the scope of my invention. These vanes can be shaped andpositioned to impart any direction of swirl, or even more than one direction of swirl, to the oxygen streams. The nozzle can be provided with such vanes, or the like, with little difficulty by one skilled in the lance nozzle art having the present teachings to guide him. it is generally desirable for lance nozzles to impart flow patterns to effluent oxygen streams such that the streams penetrate the furnace melt toa certain extent to stir up impurities, yet provide sufficient coverage of the melt surface to burn off as many of these impurities as possihie. In this connection. swirling currents in the oxygen "have the melt surface, such'ns created by the aforesaid vt'mcs, or'the like. contribute to u more efficient burnott' oi the impurities stirred up by the interaction between the oxygen and the melt.

While the novel lance nozzle of this invention has been herein described and illustrated in what are considered to be preferred embodiments, it will be understood by those skilled in the art that variousdepartures may be made therefrom within the scope of the inven tion. Certain of these departures have already been mentioned, and others will occur to those skilled in the art in the light of present teachings. An example of the latter would be the inclusion in the nozzle of a type of seat; means other than notched ribs 60,.for the lower end of middle pipe 50of lance shank-64. One purpose of the seat means is to provide support for the middle lance shank pipe ata proper height to permit the flow of coolant through the space between the bottom of thispipe andthe bottom of the nozzle at a suitable rate to achieve the desired cooling effect. Another purpose of the seat means-is to assure substantially concentric positioning of the lower end of the middle lance shank pipe and noule relative to one another.

Obviously, the use of any seat means designed to support the lower end of the middle lance shank pipe at a desired level'above the bottom of the lance nozzle, in a way to accomplish the foregoing purposes, falls squarely within the scope of my invention. Perhaps less obviously, the nozzle still falls within the scope of my invention if it'has no such seat means present at all (unless its outer walls can be considered'seat means), because it is conceivably possible to maintain the middle lance shank pipe in proper positional relationship to the nozzle by means other than seat means on the nozzle itself.

In summary, the scope of the present invention extends to all variant forms thereof encompassed by the language of the following claims. Although the nozzle has been particularly described and illustrated with emphasis on its applicability as an oxygen. injection lance for use in steelmaking furnaces, it is'not limited to-this particular application, and any nozzle embodying the structural essence of my invention, as taught herein, regardless of its contemplated use or purpose, is a legitimate embodiment of the invention so long as it-meets the structural requirements of the language of said claims.

I claim: 1. Nozzle means particularly suitable for use as the tip of an oxygen injection lance, said injection lance beingtof the type having a shank comprising three con-. centrically arranged pipes forming an internal passageway of circular cross section for oxygen flow, and two annular passageways for the respective inflow and outflow of a liquid coolant for saidnoule means, said nozzle means being of generally bell-like shape and having top and bottom surfaces of circular periphery;

said nozzle means having a plurality of generally sectorial passageways running therethrough between openings in its top and bottom surfaces; and having, additionally, a central hollow, enclosed at the top and bottom, running coaxially therethrough; said generally sectorial passageways being separated by webs which extend radially outwardly from a hub-like central portion of said nozzle means; said webs having slotted hollows. enclosed at the top and bottom, which run horn openings around the sides of the nozzle meant to the central hollow therein;

said nozzle means being adapted for permanent attachment to said shank, with the innerpipe of the latter secured to the top of the nozzle means and the outer pipe of said shank fixedly secured to the nozzle means in such fashion as to form at least the major portion of a cylindrical wall which merges with said nozzle means around the outer periphery of its lower end;

whereby the oxygen injection lance can be employed above the melt in a steelmaking furnace to permit the feeding of oxygen through said shank and into the generally sectorial passageways through said nozzle means for distribution of the oxygen onto the surface of the melt in a widespread pattern, and coolant can be fed downwardly, through the annular passageway between the inner and middle pipes of said shank, from whence it circulates into and through the slotted hollows in the webs of said nozzle means, and then upwardly, away from the nozzle means, through the annular passageway between the middle and outer pipes of said shank. 2. Nozzle means in accordance with claim 1 having seat means for the lower end of the middle pipe of said shank positioned to assure sub-stantially concentric relationship between the middle and inner pipes of the shank and to provide support for the lower end of said middle pipe at a predetermined level between the tops and bottoms of the slotted hollows in said webs.

3. Nozzle means in accordance with claim 1 adapted to impart swirling flow patterns to the streams of oxygen directed onto the surface of said melt during usage of said oxygen injection lance.

4. Nozzle means in accordance with claim 3 in which said swirling flow patterns include both clockwise and counterclockwise currents.

5. Injection lance means including, as tip means therefor, nozzle means in accordance with claim 1.

6. Nozzle means particularly suitable for use as the tip of an oxygen injection lance, said injection lance being of the type having a shank comprising three concentrically arranged pipes forming an internal passageway of circular cross section for oxygen flow, and two annular passsageways for the respective inflow and outflow of a liquid coolant for said nozzle means, said nozzle means being'of generally bell-like chape and having top and bottom surfaces of circular periphery;

said nozzle means having a plurality of generally sectorial passageways running therethrough between openings in its top and bottom surfaces; and having, additionally, a central hollow, enclosed at the top and bottom running coaxially therethrough;

said generally sectorial passageways being separated by webs which extend radially outwardly from a hub-like central portion of said nozzle means;

said webs having slotted hollows, enclosed at the top and bottom, which run from openings around the sides of the nozzle means to the central hollow therein;

said nozzle means being adapted for permanent attachment to said shank, with the inner pipe of the latter secured to the top of the nozzle means and the outer pipe of said shank fixedly secured to the nozzle means in such fashion as to form at least the major portion of a cylindrical wall which merges with said nozzle means around the outer periphery of its lower end; and said nozzle means having seat means for the lower end of the middle pipe of said shank positioned to assure substantially concentric relationship between the middle and inner pipes of the shank and to provide support for the lower end of said middle pipe at a predetermined level between the tops and bottoms of the slotted hollows in said webs; whereby the oxygen injection lance can be employed above the melt in a steelmaking furnace to permit the feeding of oxygen through said shank and into the generally sectorial passageways through said nozzle means for distribution of the oxygen onto the surface of the melt in a widespread pattern, and coolant can be fed downwardly, through the annular apassageways between the inner and middle pipes of said shank, from whence it circulates into and through the slotted hollows in the webs of said nozzle means, and then upwardly, away from said nozzle means, through the annular passageway between middle and upper pipes of said shank;

said generally sectorial passageways being of uniform cross-sectional size and configuration for a fixed distance from their top openings, and of radially outwardly flaring character therebelow, whereby a velocity gradient is imparted to the oxygen streams passing through the passageways so that the radially inwardly disposed portions of the streams impact the surface of the melt at higher velocity than the radially outwardly disposed portions thereof and penetrate said melt to a greater depth than the latter.

7. Nozzle means in accordance with claim 6 having cylindrical collar means integral with, and upstanding from, the peripheral edge of its lower end, the upper edge of said collar means being sized and shaped to receive the lower end of the outer pipe of said shank and permit its permanent attachment thereto for formation of said cylindrical wall.

8. Nozzle means in accordance with claim 7 in which said seat means for the lower end of the middle pipe of said shank comprises a plurality of ribs positioned in spaced apart relationship around the outer wall of the nozzle means and notched so as to receive the lower end of said middle pipe and serve as said seat means therefor.

9. Nozzle means in accordance with claim 8 in which said top and bottom surfaces are substantially flat and planarly parallel; said top surface is encircled by a depressed shoulder sized to serve as a seat for the lower end of the inner pipe of said shank; and the upper rim of said collar means is characterized by the presence of a thin, annular, upstanding flange around its inner periphery at the base of which is a narrow annular shoulder sized to serve as a seat for the lower end of the outer pipe of said shank.

l0. Nozzle means in accordance with claim 9 having angular, downwardly sloping chamfers around said depressed shoulder encircling said top surface and said narrow annular shoulder at the base of the upstanding flange at the top of said collar means, to provide space for filler metals and thereby permit strong, permanent attachment of the nozzle means to said shank.

Claims

1. Nozzle means particularly suitable for use as the tip of an oxygen injection lance, said injection lance being of the type having a shank comprising three concentrically arranged pipes forming an internal passageway of circular cross section for oxygen flow, and two annular passageways for the respective inflow and outflow of a liquid coolant for said nozzle means, said nozzle means being of generally bell-like shape and having top and bottom surfaces of circular periphery; said nozzle means having a plurality of generally sectorial passageways running therethrough between openings in its top and bottom surfaces; and having, additionally, a central hollow, enclosed at the top and bottom, running coaxially therethrough; said generally sectorial passageways being separated by webs which extend radially outwardly from a hub-like central portion of said nozzle means; said webs having slotted hollows, enclosed at the top and bottom, which run from openings around the sides of the nozzle means to the central hollow therein; said nozzle means being adapted for permanent attachment to said shank, with the inner pipe of the latter secured to the top of the nozzle means and the outer pipe of said shank fixedly secured to the nozzle means in such fashion as to form at least the major portion of a cylindrical wall which merges with said nozzle means around the outer periphery of its lower end; whereby the oxygen injection lance can be employed above the melt in a steelmaking furnace to permit the feeding of oxygen through said shank and into the generally sectorial passageways through said nozzle means for distribution of the oxygen onto the surface of the melt in a widespread pattern, and coolant can be fed downwardly, through the annular passageway between the inner and middle pipes of said shank, from whence it circulates into and through the slotted hollows in the webs of said nozzle means, and then upwardly, away from the nozzle means, through the annular passageway between the middle and outer pipes of said shank.

2. Nozzle means in accordance with claim 1 having seat means for the lower end of the middle pipe of said shank positioned to assure sub-stantially concentric relationship between the middle and inner pipes of the shank and to provide support for the lower end of said middle pipe at a predetermined level between the tops and bottoms of the slotted hollows in said webs.

6. Nozzle means particularly suitable for use as the tip of an oxygen injection lance, said injection lance being of the type having a shank comprising three concentrically arranged pipes forming an internal passageway of circular cross section for oxygen flow, and two annular passsageways for the respective inflow and outflow of a liquid coolant for said nozzle means, said nozzle means being of generally bell-like chape and having top and bottom surfaces of circular periphery; said nozzle means having a plurality of generally sectorial passageways running therethrough between openings in its top and bottom surfaces; and having, additionally, a central hollow, enclosed at the top and bottom running coaxially therethrough; said generally sectorial passageways being separated by webs which extend radially outwardly from a hub-like central portion of said nozzle means; said webs having slotted hollows, enclosed at the top and bottom, which run from openings around the sides of the nozzle means to the central hollow therein; said nozzle means being adapted for permanent attachment to said shank, with the inner pipe of the latter secured to the top of the nozzle means and the outer pipe of said shank fixedly secured to the nozzle means in such fashion as to form at least the major portion of a cylindrical wall which merges with said nozzle means around the outer periphery of its lower end; and said nozzle means having seat means for the lower end of the middle pipe of said shank positioned to assure substantially concentric relationship between the middle and inner pipes of the shank and to provide support for the lower end of said middle pipe at a predetermined level between the tops and bottoms of the slotted hollows in said webs; whereby the oxygen injection lance can be employed above the melT in a steelmaking furnace to permit the feeding of oxygen through said shank and into the generally sectorial passageways through said nozzle means for distribution of the oxygen onto the surface of the melt in a widespread pattern, and coolant can be fed downwardly, through the annular apassageways between the inner and middle pipes of said shank, from whence it circulates into and through the slotted hollows in the webs of said nozzle means, and then upwardly, away from said nozzle means, through the annular passageway between middle and upper pipes of said shank; said generally sectorial passageways being of uniform cross-sectional size and configuration for a fixed distance from their top openings, and of radially outwardly flaring character therebelow, whereby a velocity gradient is imparted to the oxygen streams passing through the passageways so that the radially inwardly disposed portions of the streams impact the surface of the melt at higher velocity than the radially outwardly disposed portions thereof and penetrate said melt to a greater depth than the latter.

10. Nozzle means in accordance with claim 9 having angular, downwardly sloping chamfers around said depressed shoulder encircling said top surface and said narrow annular shoulder at the base of the upstanding flange at the top of said collar means, to provide space for filler metals and thereby permit strong, permanent attachment of the nozzle means to said shank.