US3379428A - Lance apparatus for treating molten metals - Google Patents

Description

April 1968 A. T. DORTENZO ET AL 3,379,428

LANCE APPARATUS FOR TREATING MOLTEN METALS Filed Oct. 22, 1965 2 Sheets-Sheet. 1

INVENTORS Al. EXANDEA z aazn-wza d FLOYD F. STANDLE) Meir April 1968 A. T. DORTENZO ET L 3,379,428

LANCE APPARATUS FOR TREATING MOLTEN METALS Sheets-Sheet 9 Filed Oct. 22, 1965 r 0 Z w? mi 0 v w a m m m 1% W w L 0 H n Y B mg 1 H w m1 mm BA mwi Q I Q llillhwll N, Miflrrr mm ,l (N mm m m ww m m mv Q Q 55 L ttcs Patent Oil ice arrears Patented Apr. 23, 1968 3,379,428 LANG?) APPARATUfi FOR TREATENG MOLTEN METAL Alexander T. Bortenzo, Pittsburgh, and Floyd F. Standley, Beaver, Pa, assignors to Koppers Company, Inc.,

a corporation of Delaware Filed Get. 22, 1965, Ser. No. 501,692 4 Claims. (Cl. ass-s4 ABSTRACT OF TPE DISCLUSURE A lance for treating molten metal comprises a plurality of concentric tubular elements the innermost one of which is in fluid communication with .a fixed tubular conduit that telescopes within the innermost conduit. Within the lance tip there are a plurality of individual nozzle conduits that communicate with a transition conduit in fluid communication with one of the other concentric tubular conduits.

This invention relates to steelmaking and more particularly to a blowing lance apparatus and a method for treating molten metal such as pig iron in a metallurgical furnace.

In the process of refining molten pig iron to steel, oxygen, having a high degree of purity, is injected into the steel refining apparatus which may be either a basic oxygen converter, an electric arc furnace, or an open hearth furnace, to remove impurities in the molten pig iron. Coincidentally, additives may be injected simultaneously with the oxygen, or separately therefrom, to assist in the refining process.

Heretofore, the apparatus used to inject the oxygen and the additive materials has comprised an elongate steel tubular water cooled lance, which has a single central longitudinal passage through which the oxygen and the additives are conducted into the refining vessel. The lance is usually supported and mounted for vertical movement into and out of the refining vessel in such a manner that the oxygen and the additives impinge on the surface of the bath of molten metal at or near the central region thereof. Because the temperature within the refining vessel in the impingement zone may be as high as 6000 B, it is essential that the lance tip, which is preferably made of pure copper, be adequately water cooled.

It should be apparent that the effectiveness of both the refining oxygen and the additive material depends upon the amount of molten metal they contact in a unit of time. When, as in the prior art, there is only a single nozzle in the lance tip and is necessary to pass both refining oxygen and additives separately or simultaneously through this one nozzle, then both the oxygen and the additive material impinge against a certain surface area of molten metal. Whereas, when there are a plurality of annular refining oxygen nozzles and a central additive nozzle separate from the oxygen nozzles as in the present invention, then there is a significant and considerable increase in the eifectiveness of the present oxygen refining lance over the prior art devices due to the greater increase in surface area on which the refining oxygen impinges in a unit of time.

The present invention discloses a novel lance having a central tubular conduit terminating in a central nozzle in the lance tip through which additives may be injected into the molten metal during the oxygen blowing period, as Well as a plurality of annular oxygen nozzles in the lance tip.

For a further understanding of the present invention and for advantages and features thereof, reference may be made to the following description taken in conjunction with the accompanying drawings which show for the purpose of exemplification a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a schematic elevational view of a blowing lance in accordance with the invention, the same being shown in a first operative position;

FIG. 2 is a schematic elevational View of the lance of FIG, 1 in a second operative position;

FIG. 3 is an enlarged longitudinal sectional view of the portion of the lance of FIG. 1 below the level designated A-A in FIG. 1;

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

FIG. 5 is a view of the right-hand end of the portion of the lance shown in FIG. 3;

FIG. 6 is a sectional View along line VI-VI of FIG. 3;

BIG. 7 is an enlarged sectional view of a portion of the lance of FIG. 1; and

FIG. 8 is a schematic arrangement of a top blowing oxygen steelmalring system including the blowing lance of the invention.

A top blowing oxygen steelmaking lance in accordance with the invention, designated generally as 11 in FIGS. 1 and 2, includes an outer generally cylindrical envelope 13, a lance tip portion 15 which is conveniently secured to one end of the tubular envelope 13, and a header portion 17 which is conveniently secured to the other end of the tubular envelope .13.

The outer cylindrical envelope 13 of FIG. 1 comprises a length of steel pipe and within the envelope 13 there are four concentrically arranged and annularly spaced apart tubular conduits 19, 21, 23 and 25. The innermost tubular concentric conduit is designated 25 and the other conduits 23, 21, 19 are disposed concentrically outwardly respectively from the central innermost conduit 25, as shown in FIG. 3.

The header portion 17 is conveniently connected to the upper end of the envelope 13 by means of a pair of matching flanges 27 but, of course, welding or any other suitable connecting means may be employed if preferred. The header portion 1'7 is fitted with a pivotal bail 29 for use in supporting the lance 11 in a vertical position, such as indicated in FIGS. 1 and 2, from a crane hook (not shown) or suitable other lifting device.

Attached to the header portion 17, in the usual man ner, are an oxygen 31, and Water cooling inlet 33 and water cooling outlet 35 conduits (see FIG. 1).

The innermost conduit 25, which is adapted to convey solid particulate additive material, such as lime in pulverulent form, extends through the header portion 17 and, as shown in FIGS. 1 and 2, is secured to a fixed support member 37 by means of a suitable clamping device and fasteners 39. The upper portion of the innermost solid particulate conduit 25 passes through a studing box arrangement 4 1 that serves both as a seal against seepage of fluids from the lance and as a bearing for the conduit 25 which telescopes into and out of the lance 11 itself. The upper end of the conduit 25 is pro vided with a stop flange 43, which is welded to the conduit about where shown in FIG. 1, for the purpose of determining the vertical limit of upward movement of the lance with respect to the fixed support structure 37 (see FIG. 1). The upper end of the conduit 25 is also provided with a terminal flange 45 to which another conduit may be connected for the purpose of conveying solid particulate matter into the conduit 25.

The lower end portion of the innermost conduit 25,

which telescopes within the next outer conduit 23, is spaced apart from the conduit 23 by a spaced apart pair of spacer rings 35 which slidably engage the inner surface of the conduit 23. These rings 3-5 also seal the portion of the conduit 23 which is above the rings 35 from the portion below them, wherein solid particulate matter flows, as described hereinafter.

Referring to FIG. 3 it will be noted that the outer cylindrical envelope 13 is connected to the lance tip portion by means of welding at a joint 49. The left-hand portion of the lance tip 15 (see FIG. 3) is a generally frustoconical envelope 51 which extends from the joint 49 to another similar welding joint 53 and there joins a generally cylindrical envelope 55 Which is concentric with, but has a larger diameter than the envelope 13. The righthand end portion of the lance tip portion 15, which is actually the bottom of the lance when used as shown in FIGS. 1 and 2, is closed by an outwardly dished or convex shaped nozzle plate 57 having therein a central axial aperture 59 and a plurality of, preferably 3, annular apertures 61, regularly, angularly spaced about the central axial aperture 59. The right-hand (or bottom) end of the conduit 23 is welded to the dished nozzle plate 57 at the central axial aperture 59, as shown in FIG. 3.

The apertures 61, in a preferred embodiment of the invention, are the terminals of interior fluid conducting nozzles 63 which are formed integrally in the nozzle plate 57, as shown in FIG. 3. The axis of each nozzle 63 is outwardly biased with respect to the central axis of the lance 11 and the central axis of the tubular envelope 55, at an angle typically of about 6. Such an angle, of course, may vary with any particular installation. The inner or lef -hand ends of the nozzles 63 are welded to the ends of tubular conduits 65, and the other ends f the conduits 65 are welded to apertures in a distributor plate 67, as indicated in FIG. 6. The distributor plate 67 surrounds the conduit 23, in the embodiment of the invention shown in FIG. 3, and is welded thereto, as well as being welded to the end of a transition piece 69. The transition piece 69 is generally frusto-conical in shape and connects the circular conduit 19 to the distributor plate 67 and the conduits 65.

Within the envelope 13, there is an expansion joint 71 which is disposed above the lance tip portion 15, as shown in FIG. 1, and between adjacent lengths of conduit 19. The expansion joint 71 (see FIG. 7) is comprised of a generally frusto-conical body portion 73 which has a recessed shoulder at one end to which is welded an end of conduit 19. The tapered Wall portion 77 of the body portion 73 fits within the end portion of an adjacent end portion of conduit 19; the end wall of conduit 19 being tapered to approximately the same slope as the frustoconical surface 77.

Referring to FIGS. 1 and 2, the lance 11 is shown in FIG. 1 as being supported in a first position above a basic oxygen converter 79 in which there is a quantity of molten pig iron 91 (FIG. 8) that is ready for refining. Before the lance is lowered into the converter 79 to treat the bath of pig iron, a source of cooling water 95 is connected to the inlet conduit 33 and to the outlet conduit 35 there is connected a cooling water drain conduit 97. A first source of oxygen 87 is connected to the conduit 31, and a second source of oxygen 31 and a source of pulverulent additive material, such as burnt lime, for example, 83 is connected via conduit 85 to the flange 45 at the top of the innermost conduit 25.

Thereafter, the portion of the lance 11 surrounding the innermost fixed conduit is lowered into the converter 79 to another operative position about where indicated in FIG. 2. The innermost conduit 25, of course remains fixed relative to the support structure 37, as shown in FIG. 2, and the main lance body moves downward relative to the conduit 25. The lower end 81 of the conduit 25 moves upwardly relative to the conduit 23, but always remains within the conduit 23.

It will be appreciated by those skilled in the art that, because the lance 11 moves vertically upward and downward during the blowing period, the conduits 89, 93 and 97 are preferably flexible conduits such as metallic hose, rubber or the like.

After the lance has been lowered to the operative position shown in FIG. 2, it is ready for use in refining the pig iron 91 in the usual manner. During the blowing period of the refining process, pulverulent burnt lime is carried by oxygen from the second source 81 through the conduit 85 and into the innermost central conduit 25. Thence it is injected axially downward via conduits 25 and 23 against the surface of the molten bath 91.

Likewise, during the oxygen blowing period, oxygen flows only in the annular space between conduits 23 and 21, until the oxygen meets the distributor plate 67 whereupon the oxygen divides into three substantially parallel flow streams in the conduits 65. At the lance tip, however, the oxygen enters the nozzle 63 and is then diverted angularly outward and away from the longitudinal axis of the lance at an angle typically about 6, as mentioned previously.

From the time the lance is first lowered into the converter 79 until it is retracted and moved away from the furnace area, cooling water circulates continuously within the lance 11. The water flows into the lance via the conduit 33 and downward therein in the annular space between conduit 19 and conduit 21. In the lance tip portion 15, the cooling water flows in the annular spaces between the conduits 19 and 21. and around the conduit toward the nozzle plate 57. In the nozzle plate 57, the water reverses its flow direction after passing a baffie plate 58, indicated generally in FIG. 3, and then flows upwardly in the annular space between conduits 13 and 21 to the outlet conduit 35. At that point the cooling water exits from the lance 11.

A feature of the invention is that the refining oxygen is conducted to the lance tip portion 15 by means of a centrally disposed single axial conduit 19 and that in the lance tip region the oxygen flow is divided into three separate parallel flow channels in conduits 65. Each conduit 65 has an individual nozzle 63 at the end of the lance tip which diverts the oxygen flow angularly outward from the central longitudinal axis of the lance. A particular advantage of such a conduit arrangement is that the cooling water floods the interior of the nozzle tip more completely and provides more effective cooling of the lance tip which prolongs substantially the operative life of the lance tip.

Another feature of the invention is that the pulverulent additives, such as burnt lime, may be injected into a basic oxygen converter or other metallurgical furnace, through a central axial tube which is fixable relative to the converter and is telescopable in an oxygen lance. Within the oxygen lance there is a central annular oxygen conduit and a plurality of parallel branch oxygen conduits disposed in the lance tip; each branch conduit terminating in an angularly divergent nozzle annularly arranged with respect to the central additive conduit. The gaseous medium to convey the pulverulent additive materials through the lance and into the converter may be oxygen or oxygen-enriched air which is supplied by a system independent of the refining oxygen system.

Although the invention has been described herein with a certain degree of particularity, it is understood that the present disclosure has been made only as an example and that various modifications and changes may be made within the scope of the invention as defined by the appended claims.

What is claimed is:

1. A lance apparatus for use in treating a bath of molten metal comprising:

(a) an elongate tubular envelope;

(b) a closure attached to one end of said envelope;

(0) a plurality of fluid passages through said closure;

(d) a first tubular conduit annularly disposed within said tubular envelope and connecting one fluid passage in said end closure;

(e) a plurality of second tubular conduits in said closure each connecting a fluid passage;

(f) a third tubular conduit concentrically annularly arranged within said envelope and spaced from said first conduit;

(g) a transition conduit within said envelope communicating with said third tubular conduit, and

(h) a distributor plate, arranged transversely of said third tubular conduit, having therein a plurality of apertures each of which is in fluid communication with said transition conduit and respective second tubular conduits;

(i) a fourth tubular conduit concentrically annularly arranged within said envelope and surrounding said third tubular conduit and forming thereby inner and outer longitudinal annular fluid channels within said envelope;

(j) means to introduce a refining fluid into said third tubular conduit whereby the fluid traverses said third fluid conduit, said transition conduit, and said connecting second conduits and emerges from said end closure as separate streams of fluid;

(k) means to introduce a refining additive into said first conduit whereby said additive traverses said first conduit and emerges from said end closure in an axial direction;

(1) means to introduce a cooling fluid into said inner annular channel whereby said cooling fluid traverses said annular space in one direction and in said end closure said fluid reverses its direction of flow and traverses said outer annular channel; and

(m) means to discharge said cooling fluid from said molten metal comprising:

(a) an elongate tubular envelope;

(b) a first closure fixed to one end of said envelope;

() a plurality of fluid passages through said closure;

(d) a first tubular conduit concentrically annularly arranged within said tubular envelope and connectin g one of said fluid passages;

(e) a plurality of second tubular conduits in said first end closure connecting each to a fluid passage;

(f) a third tubular conduit concentrically annularly arranged Within said envelope and surrounding said first conduit;

(g) a transition conduit within said envelope communicating with said third tubular conduit, and

(h) a distributor plate, arranged transversely of said third tubular conduit, having therein a plurality of apertures each of which is in fluild communication with said transition conduit and respective second tubular conduits;

(i) a fourth tubular conduit concentrically annularly arranged in said envelope between said envelope and said third tubular conduit, the fourth tubular conduit and said envelope and third conduit defining inner and outer adjacent annular flow channels;

(i) a second closure fixed to the other end of said envelope;

(k) a fifth conduit extending through said second end closure and into said envelope, said fifth conduit being telescopable within said first conduit;

(1) means fixing said fifth conduit with respect to said metal bath;

(in) means for introducing a refining fluid into said third tubular conduit whereby said fluid traverses said third conduit, said transition conduit, and said plurality of second conduits and emerges from said first end closure as separate streams of fluid;

(n) means to introduce refining additive material into said fifth conduit whereby said material traverses both said fifth and said first conduits and emerges from said lance;

(0) means to introduce a cooling fluid into said inner annual channel whereby said fluid courses said inner channel into said end closure and therein reverses the direction of flow and courses said outer annular channel; and

(p) means to conduct said cooling fluid from said outer annular channel.

3. The invention set forth in claim 2 including:

(a) conduit means to introduce oxygen into said third conduit.

4. The invention set forth in claim 2 including:

(a) means to raise and lower the portion of said lance that surrounds said fifth conduit relative to said bath of molten metal.

References Cited UNITED STATES PATENTS 4/1964 Metz 266--34.1 X 2/1965 Kurzinski 26634.1 X 3/1965 Smith et al. 266-34.1

FOREIGN PATENTS 5/1962 Austria.

I. SPENCER OVERHOLSER, Primary Examiner.

E. MAR, Assistant Examiner.

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