US3043577A - Lance with conduits for mixing gases located interiorly - Google Patents

Description

July 10, 1962 w. v. BERRY 3,043,577

LANCE WITH CONDUITS FOR MIXING GASES LOCATED INTERIORLY Filed Oct. 20, 1960 2 Sheets-Sheet 1 INVENTOR Walter V. Berry July 10, 1962 w. v. BERRY LANCE WITH CONDUITS FOR MIXING GASES LOCATED INTERIORLY Filed Oct. 20, 1960 2 Sheets-Sheet 2 INVENTOR Wulier V- Berry i is 3,043,577 LANCE WITH C(INDUITS FOR MIXING GASES LOCATED INTERIQRLY Walter V. Berry 2679 Santa Barbara Dfive,

Pittsburgh 34, Pa. Filed on. 20, 1960, Ser. No. 63,877 4 Cls. (Cl. 266-34) My invention relates to apparatus for discharging a gas jet and more particularly to a lancefor injecting fuel gas and oxygen into an open hearth furnace for making steel.

In the making of steel it has been found to be advantageous to introduce oxygen and a combustible gas, such as natural gas, directly against the surface of the melt. Usually this is done in two operations. First a combination of fuel gas and oxygen are introduced into the furnace so as to produce a hot flame and a large amount of heat quickly in order to reduce the cold metal charge to a melted condition rapidly. After the metal has been melted and hot metal has been added it is then desirable to shut off the fuel gas and inject only oxygen into the melt for the purpose of reducing carbon to the desired point in preparation for tapping the furnace. I

' believe that this can best be done by a combination device comprising a burner mechanism whereby the gas and oxygen willbe mixed together to form a blue flame when they are both being ejected together. By shutting off the fuel gas and injecting only oxygen into the burner mechanism, the burner mechanism also serves as an oxygen lance.

Since the temperature in the furnace is sulficiently high to melt the metal of the lance it has been found necessary to provide cooling means in the lance preferably by the use of water circulating therein. However, in spite of all the attempts in the prior art to cool the lance, there continues to be a rapid deterioration at the nose of the lance around the holes from which the oxygen is ejected intothe furnace. I have concluded that this is due to the combination of heat in the furnace together with the presence of large quantities of free oxygen which are being forced against the metal. In an effort to solve this, several different types of materials have been employed such as some of the highly temperature resistant and oxidation resistant materials such as have been experimented with in rockets. These have all proven to be unsatisfactory because they oxidize and otherwise deteriorate substantially as rapidly as copper. I therefore conclude that the solution to the problem lies in redesigning the lance while continuing to employ' copper which has a relatively low melting point. I have accomplished this by two approaches. First I have conceived a way to gain better circulation of cooling water in the region of the oxygen and fuel gas conduits at the nose of the lance and secondly, surprising though it may sound, I have found that by moving the flame into the interior of the lance I get less deterioration than if the flame is entirely outside of the lance.

Accordingly, it is an object of my invention to provide a lance for injecting fuel gas and oxygen into a furnace which produces a maximum of combustion.

-It is another object of my invention to provide an improved lance which has a circulating flow of #water in such a manner as to prevent deterioration of the lance due to heat.

It is another object of my improved injection burner.

It is another object of my invention to remove dangerous flashback characteristic of premixing devices.

It is another object of my invention to provide for an increase in the percentage of cold metal charge which is practical.

invention to provide an It is another object of my invention to decrease percentage of hot metal charge necessary.

It is another object of my invention to reduce tap to tap time and thereby increase production.

it is another object of my invention to provide an improved nozzle.

It is an ancillary object of my invention to provide an improved gas ejection device.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects andadvantages thereof, will best be understood from the following description when read in connection with the accompanying drawings in which:

FIGURE 1 is a showing in cross section of the nozzle end of a lance in accordance with the preferred embodiment of my invention.

FIGURE 2 is an end view of the lance shown in FIGURE 1.

FIGURE 3 is a transverse cross section taken on the line III--III of FIGURE 1.

FIGURE 4 is a showing in cross section of a portion of a lance in accordance with one embodiment of my invention wherein the separator between fuel gas and oxygen conduits at their junction is tapered.

FIGURE 5 is a showing in cross section of a portion of a nozzle in accordance with another embodiment of my invention wherein both the outside walls and the separator are tapered.

In accordance with the preferred embodiment of my invention I provide a lance for injecting fuelgas and oxygen into an open hearth furnace whereby the lance extends through the ceiling of the furnace down into the interior thereof to a point which is a short distance above the surface of the material being treated therein.

The lance comprises a shank 6 and a nozzle 8. The shank 6 comprises four cylindrical pipes which are concentric and located in spaced relationship to each other. These pipes comprise an inner oxygen pipe 10, an inner water jacket 12 around said oxygen pipe a water deflector pipe 14 around said inner water jacket 12 and an outer water jacket 16 around said water deflector pipe 14. g

The nozzle 8 which is attachedto the end of the shank 6 and has the same outside diameter as the shank 6 comprises six pairs of terminal conduits each of which conduits is one half inch in diameter and extends outward at an angle of approximately in the prefered embodiment or between 20 and in accordance with other embodiments of my invention, from the axis of the lance. Each pair of terminal conduits comprises an inner terminal conduit 18 and an outer terminal conduit 20,

the axis of each conduit of each pair of conduits lying in the same plane as the other and as the axis of the lance. The said inner terminal conduits are all joined together, at theirupper extremity toward the shank of the lance, into a common larger conduit 22 referred to herein as the large oxygen conduit. The large oxygen conduit 22 which is connected to the smaller inner terminal conduits 18 extends upward and is connected to the inner oxygen pipe 10 of the lance shank '6.

The outer terminal conduits 20' change direction at the point where the inner terminal conduits 18 are connected to the larger innerconduit and extend upward parallel to the axis of the lance adjacent to the large oxygen conduit 22.

The terminal conduits are joined together by spacers extending between each pair of terminal conduits so as to fill the space between adjacent pairs of conduits. The spacers are so formed so as to provide, in conjunction with the inner Walls of the inner terminal conduits 18, an

E inverted cone shaped indentation 30 in the nose of the cone.

The nozzle also comprises an outer cylindrical water jacket 26 which has an axis co-lineal with the axis of the shank of the lance. The outer water jacket 26 extends inward at the nose of the nozzle in a curved manner so as to contact the terminal conduits and the spacers therebetween so as to form a watertight junction therebetween and to produce a cup shaped nose 28 broken only by the inverted cone shaped indentation 30' in the nose and the terminal conduit ejection chamber described hereinafter.

Each pair of the terminal conduits comprises two parallel conduits having a common wall. The said wall between the. two conduits of each pair of terminal conduits is preferably inch thick and the conduits are preferably /2 inch. in diameter.

The wall between the terminalconduits of each pair is cutaway for a depth of one inch or a distance equal to the sum of the diameters of the two conduits from the end of the nozzle, so as to form a terminal conduit ejection chamber 31. The terminal conduit ejection chambers have walls that are rounded or smoothed off so that the cross section is substantially an oblong space having parallel sides and rounded ends. In other words, in accordance with a preferred embodiment of my invention the ejection chamber is formed by cutting away the walls between the pairs of conduits from lines on the wall of the outer conduits which are 90 from a perpendicular line between the axis ofthe outer and the inner conduit,

and which are parallel to the axis of the outer conduit, through to a corresponding line on the inner conduit.

The water jacket of the nozzle is of the same diameter as the outer water jacket pipe of the shank and the two are joined together so the axis of one is an extension of the axis of t-he'other. The inner water pipe 12 has a diameter equal to the outer edges or walls of oppositely disposed outer conduits 20 at the termination of the outer conduits 20 toward the shank. The inner water pipe 12 of the shank is fastened to the outer walls of the outer conduits in a gas and water tight junction 32. The water deflector pipe 14 extends between the outer water jacket 16 and the inner water jacket 12 co-axially therewith and in spaced relationship thereto and extends into said nose to' a point approximately opposite the region where the inner terminal conduits 18 are joined together into the large inner oxygen conduit In the operation of the device in accordance with the 7 preferred embodiment of 'my invention, oxygen is injected terhtinal conduits 18 to the terminal ejection chamber 31.

A fuel gas, such as natural gas, is injected into the region between the inner-oxygen'pipe 10 and the inner-water jacket 12 flowing down through the lance and out through the outer terminal conduits 20 to the terminal conduit ejection chamber 31. In the terminal conduit ejection chamber 31 the two gases mix together and combustion occurs. The flame thus produced begins in the ejection chamber 31 and extends fora distance of one to three feet beyond the end of the lance. I have found that with this arrangement a good blue flame is obtained which is well seated inside the ejection chamber 31. I have also found on experimentation that the device does not operate as 'well if the oxygen and fuel gas are reversed. A better flame is obtained if the oxygen and the fuelgas are injected as described above although the device is operable if the gasses are reversed.

' Wateris injected into the region between the innerw-ater jacket 12 and the water deflector pipe 14 and flows down to the nose 28 of the lance coming in contact with the inside of the metal spacers between the conduits and flows back up' along the outer wall,26 of the lance. I have found that by this configuration a constant and continuous flow of water is directed against the walls that need to be cooled. Devices in the prior art have employed e of the hole.

noses which were either fiat or only slightly indented, whereby there was no direct flow ofwater between the terminal conduits 12, 20 in the region behind the center of the nose 30, therefore, a great deal of turbulence was pro-. duced and very poor circulation. By effectively raising the indentation 30- in the nose up to where it is effectively coextensive with the walls of the terminal conduits 18, 20 I am able to get water to how smoothly and continuously along the walls of the nose without turbulence and thereby obtain a better cooling effect than is true in fuel gas-oxygen burners of the prior art.

It will be noted that the biggest problem in constructing a lance of this type is finding a way to combat the tendency of the metals to oxidize around the conduit openings in the nose. This oxidation is due to the tremendous temperatures involved together with the presence of a large quantity of pure oxygen. I have found that with the device as described herein the rate of deterioration is greatly reduced. I believe that this is partially due to the fact that by the time the oxygen reaches the outer surface of the nose of the lance it is no longer pure oxygen, but is mixed with fuel gas. Since it is at the outer surface of the lance nose Where the greatest heat is involved, that is the place where oxidation is most'likely to occur. Since the oxygen is mixed with fuel gas at that point there is less deterioration at the surface of the nose because effectively the fuel gas shields the nose from half of the oxygen.

It should be noted that we have overcome the problem of deterioration by effectively jumping from the frying pan into the fire. We have moved the fire from outside of the lance into the interior of the lance and thereby produced less damage to the lance than was present with the fire outside of the lance. This is a surprising result. However, we have found in practice that a drastic improvement is produced by this construction.

It should also be noted that'in the construction of the device in accordance with the preferred embodiment of my invention, the flame begins inside the lance. There will therefore be a tendency of the flame inside of the ejection chamber of the lance to heat the walls of the chamber. It is therefore important thatthe walls of the ejection chamber be cooled as much as possible. For that reason it became even more important to find a better cooling system, which need sparked part of this invention.

In accordance with other embodiments of my invention as shown in FIG. 5, I provide pairs of terminal conduits opening into an ejection chamber whereby the terminal conduits of each pair near their termination in the ejec-' tion chamber are sloped toward each other at approximately 15 from the parallel position. The terminal conduits and the outer walls of the ejection chamber are also tapered inward toward the nose so that the outer walls of the ejection chamber form substantially an extension of the line along the walls of the terminal conduits in the region near their connection with the ejection chamber. Thus the end of the ejection chamber toward the end of the nose of the lance is substantially smaller than the cross section-a1 area of the ejection chamber in the region where it is connected to the two conduits. I have found that this embodiment is advantageous in situations where a substantial amount of difficulty is encountered due to splashing of slag and other materials in the furnace against the nose of the lance. By restricting the size of the opening at the surface ofthe lance nose to,

increase the pressure of the oxygen at the surface of the lance so that it tends to blow'away foreign materialfrom the entrance intothe ejection chamber, I thereby discourage the slag or other mat'er'i plugging part By this arrangement eliminate the proble'm that has been encountered with the gas terminal conduit becoming plugged with slag when no gas is being injected into the lance, i.e., when. the lance is be ing employed solely as an oxygen lance. As was ex-' pla-ined above, this lance is preferably used in a cycle whereby fuel gas and oxygen are employed together until suificient heat is produced in the furnace, then the fuel gas is shut oif and oxygen alone is fed through the lance for reducing the carbon in the melt. It is while the lance is being employed purely as an oxygen lance that there is a tendency for the slag to move up into the ejection chamber and to plug the end of the fuel gas terminal conduit.

In accordance with another embodiment of my invention, as shown in FIG. 4, I provide two terminal conduits extending parallel to each other and opening into an ejection chamber, the outer walls of which are parallel to the outer walls of the conduits. The two conduits are separated by a common wall which is tapered from a point approximately one inch from the ejection chamber to a point at their termination in the ejection chamber. I have found that this embodiment has some tendency to prevent slag from entering the fuel gas conduit when oxygen alone is being fed through the lance. By having the inner wall tapered the oxygen tends to spread out into a stream of a larger cross section so that it substantially fills the exit opening of the ejection chamber at the surface of the nose. By having the inner wall tapered it also provides a velocity component in the oxygen stream which is perpendicular to the main direction of flow of oxygen through the terminal conduit.

In FIGURES 4 and 5 references to identical part-s shown in FIGURES 1-3 are the same with a prime and double prime fixed thereto respectively.

Although I have shown and described specific embodiments of my invention, I am aware that other modifications thereof are possible; my invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and the spirit of the invention.

I claim as my invention:

1. A lance comprising an inverted cone shaped shell, a substantially flat disc surrounding the base of said cone e and forming an extension of the edges of said cone, said disc having a plurality of oblong holes there through, the holes being divided by a thin wall extending inwardly from a point distant from the surface of said disc approximately equal to the long dimension of said holes as measured on the surface of said disc.

2. A nozzle comprising a cup-shaped, nose, a plurality of paired conduits extending through said nozzle end, each 'pair of said conduits ending in an enlarged common indentation in said nose, said common indentation being in' depth equal approximately to the sum of the diameters of the said pair of conduits connected thereto.

3. An oxygen fuel gas lance comprising a nose piece having an indentation therein, said indentation being of tapered cross section with its larger end toward the surface of said nose piece, a pair of conduits inside said lance terminating in said indentation a substantial distance from the surface of said nose piece, said conduits, at the ends thereof, being oriented so that the extensions of their axes converge a short distance beyond the end of the nose of the lance.

4. A fuel gas and oxygen lance comprising two parallel conduits extending to the surface of the nose of the lance, said conduits having a common wall therebetween, said partition being tapered at approximately 15 from a point deep in the interior of the lance, so a fine line at its termination at a point located a distance from the nose of the lance approximately equal to the sum of the diameters of the said conduits. 7

References Cited in the file of this patent UNITED STATES PATENTS 1,949,731 Soldatorf Mar. 6, 1934 2,807,506 Gehring Sept. 24, 1957 2,863,656 Cox Dec. 9, 1958 2,937,864 Kesterton May 24, 1960 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pat. No. 3,043,577 July 10, 1962 Walter V. Berry It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 26, for "so" read to Signed and sealed this 23rd day of October 1962.

(SEAL) Attest:

ERNEST w. SWIDER DAVID L LADD Attcsting Officer Commissioner of Patents

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