US3071363A - Steel manufacture - Google Patents

Description

Jan. I, 1963 R. P. A. MACKAY 3,071,363

STEEL MANUFACTURE Filed April 27, 1961 2 SheetS -Sheet 1 10 I: nii 14- 22 19A 155: W 15 7 i|,i l :ilslii I I v I I. I i i.

INVENTOR RONALD PETER Ausm/R AMCKAV A TTOR/VEYS Jan. 1, 1963 R. P. A. MACKAY 3,071,363

STEEL MANUFACTURE Filed April 27, 1961 2 Sheets-Sheet 2 IN VE N TOR RONALD PETER AL/STA/R MAC/(A A TTORNEYS United States Patentofilice Patented Jan. 1, 1963 3,071,363 STEEL MANUFACTURE Ronald P. A. Mackay, Abbey Works, Port Talbot, Glamorgan, Wales, assignor to The Steel Company of Wales Limited, Glamorgan, Wales Filed Apr. 27, 1961, Ser. No. 106,073 1 Claim. (Cl. 266-411) This invention relates to the application of oxygen in the manufacture of steel in steel refining apparatus and more particularly the open-hearth furnace. It relates, in particular, to an improved apparatus for the injection of oxygen in the form of a jet into the steel refining apparatus which will be hereinafter referred to as an open-hearth furnace but which is intended to cover steel refining apparatus such as stationary and tiltable open-hearth furnaces, stationary and tiltable mixers both of the inactive and active type.

It is the main object of the invention to provide an improvement in an oxygen delivery pipe or gun which is retractibly mounted on the roof of the furnace for lowering through an opening in the roof. The gun is so arranged that the stream of oxygen is delivered on the charge in the furnace in the form of a jet which is at near sonic speed and at an angle from the vertical so that the spray of molten steel and slag is directed away from the tip of the gun which thereby greatly prolongs the life of the gun. In this prior arrangement the angular delivery of the oxygen jet is obtained by providing the gun with a copper end bent at an angle of approximately 25 with the tip of the gun about five inches above the steel bath.

The present invention sets out to provide an oxygen delivery pipe or gun modified by providing its end portion with a plurality of delivery passages each for directing a stream of oxygen at an angle from the vertical on to the steel bath. It will be appreciated that the arrangement provides a more efiicient discharge of the oxygen stream on to the steel bath in that a greater area of the steel bath will be covered simultaneously by the discharge of a number of oxygen streams. Furthermore, for a given oxygen flow splashing is considerably reduced. The invention also sets out to provide a more efiicient cooling of such a multi-jet gun or pipe.

According to the invention there is provided an oxygen delivery gun or pipe for use in the manufacture of steel in an open-hearth furnace, said gun or pipe comprising an elongated barrel, a tubular member centrally located within said body for the passage of oxygen therethrough and terminating short of the nozzle of the gun or pipe, a plurality of passageways connecting the end of said tubular member with a plurality of discharge ports spaced about the nozzle of the gun, and a plurality of pipes angularly spaced about the tubular member for conveying cooling liquid to the nozzle of the gun or pipe, wherein two of said passageways are spaced apart sufliciently to allow one of said cooling pipes to extend downwardly between said passageways and into the nozzle of the gun or pipe so as to direct cooling liquid directly into the space between the passageways at the end of the tubular memher.

The invention will now be described with reference to the accompanying drawings, in which:

FIGURE 1 is a transverse vertical cross-section of an open-hearth furnace showing the oxygen gun of the invention in its lowered position;

FIGURE 2 is an elevational view of the oxygen gun with portions of the wall removed to show the cooling arrangements;

FIGURE 3 is a vertical sectional view of the oxygen gun in FIGURE 2;

FIGURE 4 is an enlarged sectional view taken on the line 44 of FIGURE 2 and showing the arrangement of the coolant pipes about the central oxygen tube and discharge passageways; and

FIGURE 5 is an enlarged sectional view of the tip of the gun taken on the line 55 of FIGURE 4.

Referring now to the drawings, and more particularly to FIGURE 1 wherein like reference numerals indicate the same parts throughout the various views, the oxygen gun assembly indicated at 1 is supported by a cable 2 extending over a pulley 3, secured in the roof of a building containing an open-hearth furnace indicated at 4. The cable 2 extends horizontally to another pulley 5 and down to the winding drums 6 of an electrically operated winch 7 secured to girders above the furnace or in any other suitable position.

The gun assembly 1 extends downwardly through an opening Sin the roof 9 of the open-hearth furnace 4. The opening 8 is in a panel of chrome magnesite bricks 10 which is inserted in the roof of the furnace 4. Located within the opening 8 is an annulus 11 which surrounds the gun assembly 1.

A guide 12 for the oxygen gun is positioned directly above the opening 8 upon a 'beam construction indicated at 13. The guide is for the purpose of assisting the cable in supporting the gun in position and to prevent the gun from rotating within the furnace when it is in its operative position.

Proceeding next to FIGURES 2 and 3 which illustrate sembly 1 comprises a copper barrel 14 to which is affixed at the lower end thereof a cast copper nozzle 15, e.g. by welding.

Secured to the upper end of the barrel 14 is a U-shaped connecting member 17 to which the cable 2 is attached. Extending from the upper portion of the gun body is a downwardly curved pipe 18 which is the inlet of the cooling water. The pipe'18 is connected to the open top ends of three pipes 19 which extend the length of the oxygen gun and surround a centrally located pipe 20 through which oxygen is passed.

As the cooling water emerges from the ends of the pipes 19 it passes upwardly as indicated by the arrows 22 in the space between the walls of the gun and the pipe 19 and 20. When the water reaches a chamber 23, it passes outwardly through a downwardly bent pipe 24. A plate 25 separates the water outlet chamber 23.

As may be best seen in FIGURE 1, a hose 37 connects the water inlet pipe 18 to a source of cooling water. A hose 38 connects to the water outlet pipe 24 to convey the heated water to a suitable cooling source.

A hose 26 connects the oxygen pipe 20- to a source of oxygen.

Near the upper end of the gun body 14 there is a pair of radially extending locating bars 27. These bars are of high grade steel and are used to support and locate the gun in the gun guide 12 which not only positions the gun but also serves to support the gun above the furnace should there be a failure of the supporting cable.

Annulus 11 is used to cool the opening 8 in the roof of the open-hearth furnace. By cooling this opening, the furnace gases escaping from the opening will be cooled and their cutting action on the roof and the position of the hole will be considerably reduced. The annulus 11 comprises a continuous length of steel tubing which is in the shape of a coil. The cooling water enters through the water inlet 34 and circulates through the coil from the bottom upwardly to be exited from the water outlet 35. The use of a roof cooler in the form of a continuous coil has the outstanding advantage in that there is a constant flow of the cooling water throughout the entire annulus. This results in a constant maximum flow rate through the entire coil. By having a constant maximum A fiow rate, the life of the water-cooled annulus is greatly improved, this improvement being on the order of a fivefold increase in the life of the annulus.

Referring now to FIGURES 4 and 5 it will be seen that the centrally located oxygen delivery pipe 20 is welded at its lower end to a corresponding pipe 39 forming part of the copper-nozzle 15. The pipe 39 is closed at its lower end as indicated at 40 so as to leave a space 41 between the wall 40 and the lower wall of the nozzle 15. The lower end of the wall of the pipe 39 adjacent wall 40 is formed with a plurality of passageways 42 which extend outwardly at an angle to pipe 39 to provide a series of discharge ports 43 in the base of nozzle 15. In the drawings five passageways are provided. An important feature is that the passageways 42 are not symmetrically located around the pipe 39. As shown in FIGURE 4, the passageways 42 are located 60 apart with the exception of passageways 42A and 428 which are spaced 120 apart. The passageways are all inclined at an angle of about 20 to the vertical axis of the gun so that the stream of oxygen through pipe 20 is divided into five separate jets each directed outwardly from the gun axis. When the nozzle of the gun is located about 4 to 5 inches about the steel bath indicated at 36 there is a considerable reduction in splashing compared with a single orifice gun. For similar oxygen delivery rates of 30,000 to 60,000 cu. ft. per hour, the individual delivery rate of each nozzle 43 is reduced to 6,000 to 12,000 cu. ft. per hour and as the streams of oxygen are directed outwardly from the gun there is a considerable increase in the life of the gun and less damage to the furnace walls due to the reduction in splashing.

An important problem of the gun of the present invention'is the necessity of providing adequate cooling of the nozzle 15 around the passageways 42 otherwise the life of the gun is short. The passageways 42 tend to restrict the flow of cooling water from the pipes 19 which with a symmetrical arrangement of the passageways 42 would largely result in the cooling water emerging from the ends of the pipes 19 and returning directly up the space between the pipes 19 and 20 and the gun barrel 14. As shown two of the pipes 19 extend downwardly to the beginning of passageways 42 but by providing the space 44 between passageways 42A and 42B it is possible to extend the other cooling water pipe 19A downwardly to a position adjacent the lower wall of nozzle 15. The end 45 of pipe 19A is angled so as to ensure that the discharge of the cooling water is directed into the space 41 between the passageways 42 as indicated by the arrows 46. In this manner an efficient cooling of the nozzle is obtained which is essential if an economic life for the gun is to be obtained.

If desired, more than one gun may be provided. By the delivery of oxygen in accordance with the invention through the root of the furnace and providing means for retracting the gun or guns, other operations essential to the open-hearth furnace, such as charging, and tapping the furnace, are not interfered with in any way and the invention may thus be easily applied to existing furnaces. The manipulation of the delivery pipe assembly is extremely simple and the operation requires very little manual attention.

I claim:

An oxygen delivery gun for use in open-hearth furnaces comprising an elongated barrel having a closed lower end with five nozzle outlets, a tube positioned centrally in said barrel and having five downwardly extending and radially diverging nozzles, each of which terminates in one of the nozzle outlets, four of the five passageways between nozzles being angularly displaced from one another and the remaining wide passageway being angularly displaced from each of the two adjacent passageways, three equally spaced pipes extending downwardly in the space between the barrel and the tube, one of the pipes extending along the middle of the wide passageway and terminating close to the lower end of the barrel while the other two pipes terminate at a higher level, means for delivering cooling water into the upper ends of the pipes, and means for delivering oxygen into the upper end of the barrel.

References Cited in the file of this patent UNITED STATES PATENTS 1,849,072 Clark Mar. 15, 1932 2,807,506 Gehring Sept. 24, 1957 2,827,279 Cox Mar. 18, 1958 2,836,411 Auer May 17, 1958 2,937,864 Kesterton May 24, 1960 FOREIGN PATENTS 852,078 Great Britain Oct. 26, 1960

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