US3119889A - Steel making apparatus - Google Patents

Description

Jan. 28, 1964 R. F. oBENcHAlN 3,119,889

- STEEL MAKING APPARATUS Filed NOV. 13, 1959 AEA-22 :un EL e Il Fav/o F. srn/vaLA-K IN V EN TORS.

United States Patent O 3,119,889 STEEL MAKENG APPARATUS Richard F. Qhenchain, Pittsburgh, and Floyd F. Standley, Beaver, Pa., assignors to Koppers Company, Inc., a corporation of Delaware Filed Nov. 13, 1h59, Ser. No. 352,795 3 Claims. (Cl. 2645-35) This invention relates to apparatus for an oxygen steel making convert-er and more particularly to apparatus for supporting a lance for supplying oxygen for such'a converter.

A long tube or lance is frequently used tov force oxygen into contact with the surface of molten pig iron in an oxygen converter as is required in conventional steel making practice to eliminate certain chemical elements from the pig iron. General information on this procedure is well-known in the prior art as evidenced by the following publications, Development of Oxygen Steelmaking, by O. `Cuscoleca (Journal of Metals, July 1954) and The 49th BlSRA Steelmaking Conference (Iron and Coal rades Review, March 7, 1958) with emphasis on pages 818 and 819 of the former and pages 563 and 564 of the latter. The lance is usually inserted into the open end of a closed bottom converter, and a high velocity jet of substantially pure oxygen is forced downwardly from an orice at the end of the lance against the molten metal in the conventer. By ejecting the oxygen at velocities in the transonic and supersonic ranges the effect is to cause this oxygen tolstrike the surface of the bath initiating the reactions which in turn violently agitate the bath due to the .temperature and density diderentials created between that portion of the bath surface under the oxygen jet (primary reaction area) and the rest of the bath. The froth and gases in the converter above the surface of the bath are likewise in a whirling turbulence and it is to be expected as is, in fact, the case that under the combined iniuences of the reaction from the ejected oxygen blast and the buieting action of the churning gases in the converter, the lance will be subjected to forces producing violent rotating and rocking actions the lance. As a result, these actions induce such severe vibrations in the lance as to pose a problem as to how to support the lance so as to oppose .these forces and minimize the vibrations to effectively restrain the lance to control it during the blowing operation. Such effective control of the lance during the blowing operation isdesirable to permit accurate positioning of the lance with reference to the surface of the molten metal. This posi-tioning is diflicult, however, because the level of metal in the converter and the chemical analysis of the metal vary. In response to these fluctuating conditions, frequent changes in the positioning of the lance become necessary during each oxygen blowing period. `Also, at frequent intervals the lance must be completely removed from the converter for charging and tapping of the converter.

Heretofore apparatus lfor positioning the lance consisted of a wire rope hoisting device, a guide, and a hoodrnounted clamp. lIn operation, the wire rope hoisting device lowers the lance to a desired position, the clamp is closed to support the lance so that the orifice is above the molten metal in the desired blowing position with the lance lbeing so held by the hood clamp as to counteract the bufeting forces within the converter. Since it is frequently necessary to change the relative position between the nozzle of the lance and the top of the bath during the oxygen-blowing operation, these readjustments require the engaging and disengaging of the clamp each time the lance is moved. During the repositioning of the lance the high velocity oxygen input must, of necessity, be reduced considerably since during this period the lance is substan- ICC tially unrestrained against vibration. Each time the hoodmounted lance clamp must be released and then re-engaged, the blowing operation is interrupted causing the extension thereof with resultant lack of eiciency. An additional disadvantage is that the opening and closing of the clamp for each lance adjustment plus the maintenance occasioned by frequently occurring clamp failures also restricts the availability of the vessel for the blowing operations.

Since the lance must be yof suicient length to reach to within .the proper distance from the bath, -any clamping or guiding devices placed between the two ends of the lance require additional lance length and in turn increased building height.

In existing practice the lance is suspended by wire rope and a service pipe line yand two water lines are attached to the upper end of the lance causing this lance to hang eccentrically except during the actual time that the lance is held rigidly in the vertical position by the hoodmounted lance clamp.

In order to overcome these difficulties, it has been proposed in the art to mount a lance on a web-like tower attached to the floor below the converter, to raise and lower a section of the tower by means of wire ropes and pulleys mounted in 4the tower, and to rotate the mast by means of a device mounted on top of the tower. Sucha tower, however, is bulky, must be located on .the floor which supports the converter at a relatively large distance from the converter, and may require frequent maintenance because of hot metal spillage around the converter. Also, the device for rotating the m-ast and thereby swinging the lance at the top of the tower is complicated and difficult and expensive to maintain. Additionally, it is typical Ito employ Selsyn indicators in the art to show vertical lance positioning by reproducing the rotational activity of Ithe hoisting `system sheaves. However, because of the fact that in those -systems employing the wire rope and pulley method of handling the lance the wire rope stretches and slips in the pulleys and it is difficult to properly indicate the position of the lance above the level of the material in the converter due to the false actuation of the Selsyns by this stretching and slipping.

An object of this invention, therefore, is to provide an improved means for supporting the lance.

This invention provides a novel apparatus for supporting -an oxygen lance comprising rigid clamping means moving with the lance and interconnecting the lance with fluid `actuated means for moving the lance upwardly and downwardly to position the lance in the furnace and means for rotating the lance with respect to the fluid actuated means so as to move the lance away from the furnace. By this novel expedient control of the lance is no longer hampered by clamping means at the point at which the lance passes through the hood. Since the rigid clamping means, which both supports the lance in a vertical position against the eccentric force from the weight of the hoses and Ialso opposes the rotation and rocking of the lance under the buffeting Iaction within the converter, moves with the l-ance continuously 'supporting and rigidly restraining it against vibration there is no need for cutting back the high velocity oxygen jet during the frequent repositionings of the lance. As a result, a marked decrease in the blowing time is effected with consequent increase in converter tonnage output. Also, in the prior art hood-mounted lance clamps because of their very location in a position in which they are exposed to elevated temperatures, there has been `a heavy incidence of failures resulting in high maintenance costs as well as increased length of the blowing operation. ln the present invention, on the other hand, it is necessary to open the lance clamp only when `a new lance is to be inserted in place of a defective or worn one, an operation occurring as infrequently as once in 2000 heats. Further, since the position of the lance can be positively controlled with the present rigid lance clamp which moves with the lance, the lance guide Itypically employed to guide eccentricallydepending lances through the opening in the converter can now be eliminated.

The above and further objects and novel features of the invention will appear more fully from the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are not intended as a definition of the invention but are for the purpose of illustration only.

In the drawings wherein like parts are numbered alike:

FIG. 1 is an elevational view of an embodiment of this invention;

FIG. 2 is a top plan view of FIG. 1;

FIG. 3 is a partial cross section of the supporting apparatus of FIGS. l and 2; and

FIG. 4 is a plan view of a clamp for the lance of FIG. 3.

Referring to FIG. l, this invention is advantageously used with a closed bottom converter in an oxygen steel making process but may also be used with other types of furnaces, for example in introducing oxygen into an open hearth furnace. Furnace 11, as schematically illustrated, is a conventional closed bottom converter having an outer shell 13 and an inner refractory lining 15 such as an annular wall of dolomite bricks. Auxiliary equipment includes a hood 18 for removing fumes and smoke from the converter, a charging means (not shown) for the converter 11 and lance 37 for introducing a jet of substantially pure oxygen from a suitable supply of oxygen (not shown) against the material charged into the converter. Intense heat generated in the converter during the oxygen lancing process could cause lance 37 to distort, so a water jacket (not shown) is provided for the lance.

In accordance with this invention, a mast 39 raises and lowers lance 37 relative to the converter 11. Mast 39 is mounted on a frame 41 which moves on wheels 43 which rotate on tracks 45 mounted on base 46. Extension 47 is that portion of telescoping section 57 which projects below platform 49 and has a hand wheel 48 mounted at the lower end thereof within the easy reach of an operator standing on platform 49. The mast 39 is rotatable by means of hand wheels 48 and thrust bearings S2 located in sleeve 53. To rotate the telescoping sections 55, 56, S7 as a unit each section has an extended key-like portion 71 which mates in a corresponding keyway 72 in the adjacent section.

Telescoping sections 55, 56 and 57 are slideable up and down one within another by means of a tluid, advantageously oil which is forced into the hollow interior 58 of the mast by means of a conventional pump (not shown) having a two way control valve 60 and drained from hollow interior 58 by means of turning the valve 60. Suitable sealing rings 61, such as conventional neoprene O rings in ring grooves in the outside of each section prevent leakage of the hydraulic tluid from the interior of the above mentioned sections, rings 61 being in sealing contact with the inside of the adjacent section. A bottom plate 62 of each section except section 57 has a hole 63 for the passage of fluid from the next lower section.

Advantageously the lance 37 is rigidly connected to the top section 55 by means of two vertically spaced arms 81 which have lance clamps 83, one of which is shown in an open position in FIG. 4. End 85 of the clamps advantageously force-tits on top section 55 and extends to an arcuate portion 87 adapted to receive and mate with a round portion of lance 37. Arcuate portion 89 is pivotally moveable around pin 91 held on arm 81 by lateral extensions 93. When the latter arcuate portion is moved into closed position, an opening 94 in end 95 engages Cil tongue end 101 of arm 31 and a wedge 99 forced into slot 103 in tongue end 101 of the arm 81 presses arcuate portions 87 and 89 into tight engagement about the periphery of a portion of lance 37 to rigidly support the lance and hold the pivotable portion 89 against opening.

In operation, converter 11 is charged with the required amount and kind of material for making steel. Hood 18 is placed over the open top end of the converter, and the lance 37 is swung by means of hand wheel 48 and solely through the control provided by rigid arms 81 and lance clamps S3 without benet of lance guides or similar accessories is lowered through a hole 100 in the top of the hood. Hydraulic fluid in the hollow interior of the telescoping mast 39 flows therefrom by gravity (or by the action of a double-acting hydraulic cylinder) when valve 60 is opened to its draining position. When the tip of lance 37 has been lowered to the proper height above the melt to begin the reaction, control valve 60 is positioned to prevent further drainage. A jet of oxygen is forced into the converter through lance 37 to start the reaction. During the oxygen-blowing operation as the operator secs the need for adjustment of the primary reaction area, lance 37 is repositioned quickly and without interruption of the blowing operation simply by admitting fluid to o1' removing liquid from the interior 5S of mast 39. After completion of the steel making process fluid is forced into interior S8 of the mast so that the lance 37 raises from the converter and the hood. Then the mast 39 may be turned to swing lance 37 out of the way and mast 39 is then rolled out of the way together with hood 18 on frame 41 to enable tapping and charging of the converter. For raising the mast and lance, valve 60 is closed and a fluid actuating means (not shown) forces fluid to flow from the bottom section 57 through hole 63 in the next upward section S6 and so on until the interior 58 of mast 39 is lled with fluid and a pressure is exerted against the bottom and top of each respective section so as to raise each section in turn. The position of the lance in the furnace is advantageously indicated by indicia 102 on the side of mast 39.

At intervals when the lance must be replaced clamps 83 of the arms 81 are opened by removing wedges 99 from their seated position and the pivotable portions 89 of the clamps 83 are moved out of the way so that the lance 37 is free to be removed. Another lance is then placed in clamps 83 and clamps 83 are closed by rewedging wedges 99.

It is understood from the above that this invention is not limited to a hydraulic fluid actuated telescoping mast 39, but the mast may also be raised and lowered by the operation of compressed air as well.

This invention has the advantage that the end of the lance 37 can be quickly and simply repositioned in converter 11 without interrupting the blowing operation due to the provision of rigid clamping means 83 mounted on offset arms 71 and movable with lance 37. By this device the inventors have been able to eliminate the need for reliance upon a secondary clamp affixed to some structure other than lance 37 and its actuating means, mast 39. There is also the added benetit that lance 37 may be positioned more accurately relative to the level of the material in the converter 11 because the mechanism for altering the vertical position of lance 37 provides positive movement without the slippage and stretching encountered in the wire rope and sheave positioning means of the prior art. Thus the height of the mast above its support can easily be obtained from indicia 102. Also, the described hydraulic system makes the apparatus of this invention relatively cheap and inexpensive to maintain. With the support described, the lance is not affected by the adverse conditions on the floor below the converter .and the lance is easily moveable out of the way of the lconverter for charging and tapping of the converter, for

ation has the advantage that an overhead crane can operate over the converter without requiring the crane to be as high as necessary heretofore or trapping the crane on one side of the converter during the blowing operation, which may be as high as about 50% of the time.

What is claimed is:

1. Apparatus for introducing a high velocity jet of oxygen into a closed bottom furnace comprising a lance, a support, a telescoping mast on said support comprising sections which slide vertically, one within another, hydraulic actuating means for selectively moving said sections upwardly and downwardly to raise and lower said lance to predetermined locations relative to said furnace, connecting means on said mast, and holding means for said lance for rigidly fastening said lance to said connecting means, said holding means consisting essentially of a pair of clamps releasably secured to said lance at the upper end thereof, said clamps being movable with and secured to said lance during all changes of position of said lance to continuously rigidly hold said lance against excessive vibration whereby uninterrupted oxygen blowing at maximum flow velocity may be maintained.

2. Apparatus for introducing a high velocity jet of oxygen into a closed bottom furnace having a hood thereon comprising a lance, a support adjacent said hood, a telescoping mast on said support having sections which slide vertically one within another, hydraulic actuating means for selectively moving said sections upwardly and downwardly to raise and lower said lance to predetermined locations relative to said furnace, connecting means on said mast and holding means for said lance for rigidly fastening said lance to said connecting means, said holding means consisting essentially of a pair of clamps releasably secured to said lance at the upper end thereof, said clamps being movable with and secured to said lance during all changes of position of said lance to continuously rigidly hold said lance against excessive vibration whereby uninterrupted oxygen blowing at maximum ilow velocity may be maintained.

3. In an apparatus for introducing a high velocity jet of oxygen into a furnace during the insertion of a lance into, during the positioning thereof within, and during the withdrawal thereof from a closed bottom furnace in the course of the process of making steel wherein is provided a lance, a lifting mechanism, and a support for said lifting mechanism, said lance being connected to said lifting mechanism, whereby the lance may be raised and lowered in a substantially vertical path of travel, the improvement comprising means for continuously rigidly connecting said lance to said lifting mechanism during all changes in position of said lance, said means comprising a plurality of off-set arms each having a rigid clamp formed integrally therewith, said plurality of olf-set arms projecting from said lifting mechanism and being vertically spaced from one another, said clamps being releasably rigidly a'xed to the upper end of said lance at closely spaced points to move with said lance at all times whereby oxygen ejection at maximum ilow velocity may be continuously maintained.

References Cited in the file of this patent UNITED STATES PATENTS 2,822,163 McFeathers Feb. 4, 1958 2,886,308 Boynton May 12, 1959 FOREIGN PATENTS 220,279 Great Britain Feb. 19, 1925 OTHER REFERENCES Jour. of Metals, page 398, March 1953.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,119, 889

DATED January 28, 1964 INVENTOR(S) Richard F. Obenchain and Floyd F. Standley It is certified that error appears in the above-identified patent and that said Letters Patent C are hereby corrected as shown below:

Column 3, line 69, delete the Word "clamps" and add in its place the Column 3, line '70, delete the phrase "top section 55 and extends" and add in its place the phrase --top section 55 and the arms extend".

Column 4, line 56, delete the numeral "'71" and add in its place the ,Signed and ,Sealed this T wenty-jfth Day 0f October 1977 [SEAL] Attest:

s RUTH C. MASON LUTRELLE F. PARKER Attestng Officer Acting Commissioner of Patents and Trademarks

Claims (1)

1. APPARATUS FOR INTRODUCING A HIGH VELOCITY JET OF OXYGEN INTO A CLOSED BOTTOM FURNACE COMPRISING A LANCE, A SUPPORT, A TELESCOPING MAST ON SAID SUPPORT COMPRISING SECTIONS WHICH SLIDE VERTICALLY, ONE WITHIN ANOTHER, HYDRAULIC ACTUATING MEANS FOR SELECTIVELY MOVING SAID SECTIONS UPWARDLY AND DOWNWARDLY TO RAISE AND LOWER SAID LANCE TO PREDETERMINED LOCATIONS RELATIVE TO SAID FURNACE, CONNECTING MEANS ON SAID MAST, AND HOLDING MEANS FOR

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