US2614585A - Composite pipe - Google Patents

Description

Oct. 21, 1952 J, B, WAGSTAFF 2,614,585

COMPOSITE PIPE FiledJan. 22,l 1948 www Patented Oct. 21, 1952 lCOMP() SITE PIPE James B. Wagstaff, Ridgewood, N. J., assignor to 'V Y Hydrocarbon Research, Inc., New York, N. Y.,

a corporation of, NeWJersey l Application January 22, 1948, Serial No. 3,726 l 3 claims.' (c1. 413s- 64) f This invention relates to apparatus for introducing a gas, such asoxygen or oxygen-.enriched air, intoa bath of molten metal.

' The introduction vof oxygen or oxygen-enriched airfinto a bath vcfg-'molten metal, for example, 5:

molten iron in an open hearth furnace to `accelerate the rate of reduction of the carbon content of the molten iron, has received and is receiving considerable attention by researchy personnel. In order vto obtain satisfactory results ithas been found necessary to introduce the oxygen beneath the Vsurface of the bath of molten iron where it will come into intimate contact with the carbon and effect its removal. Obviously the introduction of loxygen through a steel or iron pipe havy the end portion as the latter melts while feeding oxygen through this pipe into the molten bath.;

Such equipment has many disadvantages, among which ,may be mentioned (1) it involves the use of a cumbersome carriage for the long lengths of pipe, which carriage and lengths of pipe occupy the space near vthe -open l'hearth furnace' and therefore obstruct and otherwise interfere with the movement of the operators in the Ivicinity of the furnace, (2) it entails frequent interruption lof the feed of the oxygen into thev molten bath necessitated by the placement of new lengths of pipe on to the carriage and the connection of ysuch pipe withthe source of oxygen, (3) it involves arduous and time-consuming labor for servicing and operating the carriage which effects feeding of the length of pipe into the molten `metal bath, and (4) `it necessitates stock piling long lengths of pipe inthe vicinity of the molten metal bath. A

" It is'a'n object of this Vinvention t'o provide apparatus' for introducing a gas such,` for example,'as oxygen or oxygen-enriched air below vthe surface of a bath of molten metal, e. g., abath of molten iron in an open hearth furnace, which apparatus is compact, isk simple to construct, is efficient in operation, requires little attention by the operator and may be used for relatively long periods of time, its effective life usually being `the same or even longer than the lifeof the refractory lining'for theI furnace.

VNOther objects and advantages of this invention i 2 f will be apparent from the following detailed de scription thereof. f l c j In accordance with this invention a conduit desirably in the form of a cylindrical pipe extends throughv a wall of an open hearth furnace and has its free end disposed beneath the surface `ofthe bath of molten metal. The end of theconduit disposed exteriorly of the vfurnace communicates with a source ofoxygen or other' gas. AV highA temperature, heat-resistant refractory material completely covers' the portion of the pipe disposed within the bath of molten metal extending beyond the end of the pipe-.disposed Within .the bath of molten metal and desirably a substantial distance above the level of the-bath of molten metal. This refractory covering preferablyconsists of a plurality lof like sections eachextending along the length of theconduit with the endof one section'abutting against the adjacentend of a contiguous section, the. abuttingk endsbeing complemental and shaped toprovide a'joint having a substantial portion thereof disposedatan angle to a plane normal tothe llongitudinal axis of the conduit. -In'this-way. relatively short sections of refractory-material may be shaped and assembled vto provide a refractory cover in :which ythel joints between sections'ar`e so disposed that they do `not permit the molten metal to attack vthe metal'.conduit-through.which the gas flows.

as will be explained more fully hereinafter.

In the preferredfembodiment illustrated on the drawing the invention'fisl shown incorporated in an oxygen 'feeding device for an. open-hearth furnace and the description which followsWilL-be conned to the*fpresentil1ustrated `embodiment `of the invention. f Itwill beunderstood, however,

vscope of this invention is not .connedvfto'the embodiment herein described. n

In the accompanyingdrawing forming apart of this specification and showing for. purposes of exempliflcation` a preferred form of this invention without limiting the claimed inventionto such illustrative instance,

Figure 1 is a fragmentary verticali section through an open hearth furnace embodying my invention; 1

Figure 2l is a fragmentary verticalvsection through the lower portion of theoxygenfeeding device of Figure 1 showingjone form offhigliteinof the body portionl9.

`stantial portion thereof extending'in a plane V, tory covering; and

AFigure 4 is a fragmentary vertical section corresponding to Figure 2 but showing still another modified form of high temperature, heat-resisting refractory covering.

In the drawing II) indicates an open hearth furnace of well known type having a refractory base II on which the bath of molten metal I2 rests, this bath as customary having an upper slag layer I3. The top I4 of thisfurnace is provided withan opening I5 through which extends the leading end I6 of a metal, desirably steel, conduit I1 which in the embodiment shown in the drawing is a conventional pipe. End I6, as shown in Figure 1, is disposedben'eath the surface of the molten metal bath I2. The end of the conduit I1 positioned exteriorly of the furnace I0 is connected with a suitable source of oxygen or other gas supplied throughthis conduit to the bath of molten metal beneath the surface thereof.

shown in Figure 2, pipe I1 is protected byv a. high temperature, heat-resistant refractory cover I8. The refractory cover I8 may be 'made of any suitable material resistant to the temperatures to which the pipe I1 may be subjected; for example, well known re brick, chrome refractory, fused alumina, dolomite, magnesite or silica may be used.

The refractory cover I8 of Figure 2 consists of .a'plurality of sections each havinga bore run- 42117112 exterior walls of the pipe andthe walls of .'thisbore. Each section comprises a cylindrical -body portion I S having a cylindrical extension 26 projecting from one end thereof, which cylindrical extension is of smaller diameter than that At the other end a cylindrical recess *2i is formed having a diameter substantially the same as that of the extension 20. The sections it will be noted are all alike and are assembled on the pipe l1 so that the lowermost 'section 22 is'positioned at the end of the pipe with the walls 23 defining recess 2i projecting beyond the end I6 of pipe I1. End I6 is formed integrally as a flange 24 the outside diameter of which is substantially the same as the 'diameter of recess 2l so that this flange rfits within 'this recess.

Projection 28 of lowermost section 22 snugly fits 'within the recess 2l of the section immediately thereabove. In the same manner the proaction zo of eachl section snugly fits within the recess of a ksection vimmediately thereabove, the resulting assembly of sections resting on the Vflange 24` at the end I6 of the pipe I1. There is thus provideda refractory covering in which the joints between lcontiguous Asections have a sub;

a an angle to a plane normal to the pipe I1. In the embodiment of the invention shown in F1gure 2 the joint between contiguous sections is of stepped configuration and consists of two horizontal portions 25 and 26 connected by a vertical portion 21, which vertical portion extends at right angles to a plane normal to the longitudinai axis of pipe n. The resultant joint construction minimizes entry of molten metal through the joints between sections into contact with the metal pipe I1, since portion 21 of the joint functions as a barrier to the flow of molten metal towards the pipe walls.

The abutting walls of projection 20 and recess 2| are ground or otherwise formed to provide smooth contacting surfaces; no cement or other bonding material which would be attacked by the molten metal and provide a clearance between contiguous sections is employed.

The modification of Figure 3 differs from that of Figure 2 chiefly in that the refractory covering consists of a plurality of like sections 28 each having a bore running the full length thereof of a diameter to receive pipe I1. Each section comprises a, cylindrical body portion 29, a projecting portion 30 at one end and a complemental recess 3i 'at the opposite end. The projecting portion 30 consists of a truncated conical segment 32 and acontiguous cylindrical'segment 33. Recess 3 I consists of a cylindrical segment 34 and a truncated conical segment, 35. End .I6 of the pipe is provided with a collar 36 in the form of a threaded flange fitting within segment 34 of recess 3I. The assembly of sections- 28 forming the refractory cover rests on collar 36.

In the construction of Figure 3 each joint between contiguous sections consists of a horizontal portion 31, a conical portion 38 forming the major portion of the joint, a vertical portion 39 and a horizontal portion 40. The contacting surfaces forming the joint are shaped to-provide intimate contact between the complemental portions of contiguous sections and are free of cement or other bonding material. A joint thus results in which portions 38 andv 39 are at an angle to a plane normal to the longitudinal axis of pipe I1 portions `38 and 39 act as a barrier preventing contact of molten metal with the walls of pipe I1.

Itwill'be noted conical segment 35 of recess 3l projects beyondcollar 36 at the end I6 of pipe I1. The segment 35 provides a protective covering .for the end I6 of pipe I1 and for-collar 36 as will be explained more fully hereinafter.'

In the modification of "Figure 4 the refractory covering -consists of a plurality of sections `each comprising a cylindrical body Yportion 4 I At one end of the body portion a projection 42 is formed consisting of a truncated conical portion 43 merging into a cylindrical portion 44. At the other end a lrecess 45 is formed complemental in shape to projection 42, the recess 45 consistingV of va cylindrical segment 46 and a truncated conical segment 41. End I6 of the pipe has welded thereto a collar 48 snugly fitting within the segment 46 of recess v45 in the lowermost section. 'Ihe assembly of sections rests on collar 48. Except as here noted, the construction of Figure 4 is the same as that hereinabove described in connection with Figure 3.

In Figures 2, 3 and 4 of the drawing while `the refractory covering has been shown consisting of three sections it will be understood any desired-number of sections may be used. Furthermore, other shapes of individual sections than those shown in the drawings maybe employed as long as the shapes when assembled in abutting relationship provide joints which have aA substantial portion thereof disposed in a plane at an angle .to a plane normal to the conduit through which the gas is supplied, which joints are close fitting so that at least a portion of the joint acts as a barrier preventing penetration of the molten y drawing, the invention comprehends pipe of other metaltherethrough into contact with the walls of the conduit I'I. n

In operation the refractory covered conduit or pipe is introduced into the furnace and before the end I6 is brought into contact with the bath of molten metal the supply of oxygen is turned on. The conduit is then lowered so that it is immersed into the bathof molten metal, for example, into the position shown in Figure 1. The existing oxygen prevents the molten metal from coming into contact with the end I6 of the metal pipe or with flange 24 of Figure 2, or collars `36 and 48 of Figures 3 and 4, the portions of the lowermost section of the refractory cover projecting beyond the flange and collars shielding same and the oxygen exiting from these projecting portions under suiiicient pressure to prevent the molten metal from flowing into contact therewith. The exothermic reaction of the oxygen with the contents of the metal bath takes place in the locality of the end of the lowermost refractory section which, it will be noted, is spaced from the end I6 of pipe I1 and from the flange 24 or collars 36 and 48. The extending recessed end of the refractory covering therefore protects the end of the pipe, the flange 24 and the collars 36 and 48.

It will be noted this invention provides an improved construction for feeding a gas beneath the lsurface of a bath of molten metal, which conshapes. Accordingly, the terms pipe and "conduit are used in the claims in a broad sense to include pipe or conduit of any desired cross sectional configuration.

What is claimed is:

l. Apparatus for feeding gas into a `bath of molten metal beneath the surface thereof, coinprising a metal conduit through which the gas flows' and discharges from the free end thereof into the molten metal, a high-temperature, heatresistant refractory covering protecting the portion of said conduit in the vicinity of said free end, said covering consisting of a plurality of identical sections positioned in abutting relationship on said conduit, each of said sections having a bore running the full length thereof through which said conduit passes, each section having at one end thereof a projecting portion of reduced cross-sectional area as compared with the cross-sectional area of the body rportion of said section and a recess complemental in shape to the projecting portion at the other end thereof,

the length of said projecting portion and of said recess being at least about as great as the thickness of said body portion of said section, the recess of the terminal section disposed at said free end extending beyond said free end and the projecting portion of said terminal section being struction is compact, simple in design, efficient and durable in operation. Since the refractory coveri's made from refractory shapes all of which are the same, it is relatively inexpensive to assemble and maintain. Should any of the sections of the refractory covering for any reason become defective, it is not necessary to replace the entire covering but only such defective section.

The protective cover` for the metal pipe may be f of the ysame refractory material as the base Il. Since the refractory -cover does not support the Weight of the molten metal bath, in general, it will outlast the base I I.

It is well to observe that the through the sections of the refractory covering be of a little larger size than the overall size of the pipe which is to pass therethrough so as to avoid cracking orinjury of the refractory covering because ofthe greater thermal expansion of the pipe when the pipe with the covering theron is introduced into the hot furnace. Even though the refractory covering does not fit snugly around the pipe, molten metal is kept from iiowing up into the clearance between the covering and the pipe by the pressurized gas discharging from the end of the pipe which is immersed into the molten Vmetal bath.

Since diiferent embodiments of the invention can be made without departing from the scope of this invention, it is intended that all matter contained inl the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense. Thus while a cylindrical pipe has been shown in the bore running positioned within the recess' of the contiguous abutting section, and means on said free end for maintaining the sections of said covering on said conduit, said means being of a configuration that nts well Within -said recess of said terminal seco tion.

' 2. Apparatus as dened in claim 1 wherein thel metal conduit is cylindrical, each section of said covering is cylindrical, the projecting portion of each section comprises a cylindrical part, and the means for maintaining the sections of said covering on said conduit is a flange on the free end of said conduit.

3. Apparatus as dened in claim l wherein the metal conduit is cylindrical, each section of said covering is cylindrical, the projecting portion of each section comprises a frusto-'conical part, and the means for maintaining the sections of said covering on said conduit is a flange on the free end of said conduit. c

JAMES B. WAGS'IIAFF.

REFERENCES CITED The following references are-of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 905,948 Stromborg Dec. 8, v1908 1,330,310 Du Mazuel Feb. 10, 1920 1,949,731 Soldatoif Mar. 5, 1934 FOREIGN PATENTS Number Country l Date 82,103 Sweden Nov. 27, 1934

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