US3883078A - Method and a device for gunniting converter linings - Google Patents

Abstract

A flame dusted with a pulverized refractory is directed tangentially to a lining surface and imparted a rotary motion, in which ducts are provided in a device and intended for the feeding onto a converter lining of a pulverized refractory, fuel and oxygen issuing from a nozzle whose axis is perpendicular to that of the ducts in a plane at right angle to a nozzle axis are deflected from a longitudinal axis at a 15*-90* angle.

Description

United States Patent [1 1 Chemeris et al.

[ METHOD AND A DEVICE FOR GUNNITING CONVERTER LININGS [76] lnventors: Oleg Nikolaevich Chemeris, bulvar mira l8, kv. 69; Evgeny Vasilievich Tretyakov, ulitsa Rozy ljuxemburg, 30, kv. 32; Viktor Kirillovich Didkovsky, ulitsa Rozy ljuxemburg 30a, kv. 42; Vilen Davidovich Kanfer, ulitsa Tsusimskaua, 63, kv. 17, all of Donetsk; Nikolai Konstantinovich Paschenko, ulitsa Makara Mazaua, 74, kv. l, Zhdanov, Donetskoi oblasti; Izmail Grigorievich Zeltser, prospekt Nakhimova, 154, kv. 29, Zhdanov, Donetskoi Oblasti; Grigory Mikhailovich Ljukimson, prospekt Lenina, 45, kv, l0, Zhdanov, Donetskoi Oblasti; Alexandr Nikolaevich Bashkatov, pereulok Sadkovy, 70, kv. 72, Zhdanov, Donetskoi Oblasti; Boris Nikolaevich Melnikov, ulitsa Sechenova, 68, kv. 27, Zhdanov, Donetskoi Oblasti; Miron Yakovlevich Medzhibozhsky, perelok Nakhimova, 5, kv. 26, Zhdanov, Donetskoi Oblasti; Ilya Alexandrovich Goldberg, ulitsa Shaumiana, 47, kv. 35; Izrail Abramovich Juzefovsky, ulitsa Reshetova, 5, kv. 55, both of Leningrad; Rafail Davidovich Ratmansky, ulitsa llicha, 52, kv. 53; Viktor Nikolaevich Irkha, both of Zhdanov, Donetskoi Oblasti; Jury Nikolaevich Borisov, Hovokuznetsk Kemerovskoi Oblasti; Fedor Filippovich Kurochkin, Zhdanov, Donetskoi Oblasti, all of U.S.S.R.

[ 1 May 13, 1975 22 Filed: Aug. 31, 1973 21 Appl. No.: 393,406

Related US. Application Data [63] Continuation of Ser. No. 221,655, Jan. 28, 1972,

abandoned.

[52] US. Cl. 239/422; 239/1323; 239/552; 239/336; 239/602 [51] Int. Cl. F23d 11/16 [58] Field of Search 239/336, 602, 552, 422, 239/423, 132.3 X

[5 6] References Cited UNlTED STATES PATENTS 805,689 11/1905 Ward et al. 239/336 1,918,799 7/1933 Conley 239/336 3,185,512 5/1965 Kilgore 232/602 3,478,963 11/1969 Winn, Jr. 239/336 X 3,730,763 5/1973 Schlottmann et a1 239/336 3,782,631 l/l974 Brockly 239/336 Primary Examiner-Lloyd L. King Attorney, Agent, or Firml-lolman & Stern 7 1 ABSTRACT A flame dusted with a pulverized refractory is directed tangentially to a lining surface and imparted a rotary motion, in which ducts are provided in a device and intended for the feeding onto a converter lining of a pulverized refractory, fuel and oxygen issuing from a nozzle whose axis is perpendicular to that of the ducts in a plane at right angle to a nozzle axis are deflected from a longitudinal axis at a l590 angle.

1 Claim, 2 Drawing Figures METHOD AND A DEVICE FOR GUNNITING CONVERTER LININGS This is a divisional, of application Ser. No. 221,655, filed Jan. 28, l972 now abandoned.

FIELD OF THE INVENTION The present invention relates to metallurgy and is intended for hot patching converter linings by gunniting or gunning.

BACKGROUND OF THE INVENTION At present the hot patching of the converter linings is carried out by the application of the wet gunniting process, for instance, by pulp-spraying.

Low quality of the gunite produced by the above method and conditioned by the need to introduce low melting-point binders and plasticizing agents into a gunnite batch; abrupt and deep cooling down of the lining surface, to be repaired, resulting in thermal spalling of refractory materials; the need for the continuous heating up of the placed gunite to produce ceramic bonds between the grains of a highly refractory consistuent of the gunite; inadequate sticking to tar concrete (tar-dolomite refractories) these and a series of other disadvantages do not enable the wet gunniting procedures to be effectively used for the hot patching of the converter lining.

Widely known is also a method of gunniting the converter lining with the aid of a fuel-oxygen torch shoot ing a pulverized refractory fed into its flame.

With the flame gunniting method the above disadvantages are practically completely avoided. As to the quality aspects of the gunite, it ranks with the best types of highly-refractory burned articles: up to 3% porosity is'provided and a structure featuring a large number of direct bonds; the gunite produced becomes selfsupporting during the gunniting interval; no thermal shock is encountered and depositing to tar concrete is quite adequate.

However in gunniting with a uniflow flame (the flame directed at right angle to a working surface of the lining, being gunnited) peculiar to the flame gunniting process is low gunning efficiency of low yield (gunning efficiency is a weight ratio of a gunite built-up to the lining zone under repair to that of a refractory gunite constituent fed to a repair zone). In that case the gunning efficiency or yield is usually equal to -20 percent but not in excess of 40 percent.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for gunniting converter linings which substantially increases efficiency of gunniting, enable the production of a slagand heat-resistant gunite containing basic refractories, tar concretes among them, avoid the loss of usable time in gunite burning and preclude the possibility of thermal spalling of the refractory lining during repairs.

According to the specified and other objects the apparatus used in a method of gunniting a converter lining with a flame dusted with a pulverized refractory, conforming to this invention, in such that the said flame is directed tangentially to the lining surface, and imparted a rotary motion relative to a longitudinal axis of the converter.

To put the above method into effect a device has been developed comprising pipes or ducts arranged concentrically relative to each other and intended for feeding onto a converter lining a pulverized refractory, fuel and oxygen to be issued from a nozzle whose axis is at right angle to that of the pipe lines with the latter being deflected, conforming to the present invention, from the longitudinal axis at a l5-90 angle in a plane perpendicular to the nozzle axis.

To make the nature of the present invention more fully apparent described below is an exemplary embodiment of the proposed device to be considered with due reference to the accompanying drawings, in which:

DESCRIPTION OF THE DRAWINGS FIG. 1 shows a converter and a gunniting device, conforming to this invention; and

FIG. 2 is a cross-sectional view of ducts of a converter gunniting device.

DESCRIPTION OF A PREFERRED EMBODIMENT A device for the flame gunniting of converter linings is a tuyere hereinafter referred to as lance 1, attached mechanically on manipulator 2 mounted on selfpropelled truck 3 On the opposite side manipulator 2 is connected to header 4, which encloses flexible metal pipes 5, 6 and 7 whose purpose is to supply to lance 1 respectively a mixture of a pulverized refractory with the fuel and oxygen and to feed and drain water which serves for cooling lance 1.

Self-propelled truck 3 is designed for handling both manipulator 2 and lance 1 over a shop working floor and for imparting lance 1 a reciprocating motion in the course of gunniting. The manipulator allows fixing lance 1 in a preset position in the converter interior imparting it during the gunniting operation, if necessary, a rotary motion over a generatrix of a cone, altering simultaneously its angle of inclination relative to its axis of rotation.

Lance 1 consists of nozzle 8 and four ducts 9 arranged concentrically and intended for supplying nozzle 8 with the mixture of the pulverized refractory with fuel and oxygen and water.

The refractory powder-fuel mixture is fed along central duct 10 (FIG. 2) while the second duct 11 is employed for feeding the oxygen under pressure. The third and fourth ducts 12 and 13 serve to supply and drain high-pressure water.

Maximum diameter of the external lance duct is mm with the minimum diameter amounting to 108 mm. An axis of lance nozzle 8 is directed at right angle to the ducts, the latter being deflected from a longitudinal axis at an angle of l590 in a plane perpendicular to the nozzle axis.

For continuous gunniting, the axis of nozzle 8 shall be tangential in relation to a cylindrical surface of the lining of converter 14 (in FIG. 1 the working surface of the converter lining is shown by a dotand-dash line) with nozzle 8 disposed in the immediate vicinity of the lining surface.

Construction of lance 1 with nozzle 8 perpendicular to the axis of ducts 9 makes it possible to shoot the flows of the pulverized refractory mixed with the fuel and oxygen against the lining of the converter cylindrical part, i.e., against lining sections exposed to the most intensive wear. However due to a taper of a converter mouth straight ducts 9 make possible impractical location of nozzle 8 near the surface of the cylindrical portion of the lining in a zone adjacent to a butt joint with the converter mouth or near the surface of the converter mouth lining. Deflection of ducts 9 in a plane perpendicular to the nozzle axis at an angle of l590 which is close to a taper of the converter 14 mouth, tends to eliminate the above disadvantage inherent in lances with straight-line ducts. However duct deflection shall be reduced to a minimum, as an increase in an angle of bending of the ducts results in a substantial growth in duct weight and hence the weight of the lance, as a whole; in addition the resistance encountered by the refractory powder-fuel mixture on its way 'to the lance is also liable to increase. With ducts 9 deflected at an angle more than 90 serious difficulties can arise in introducing the device into the converter interior prior gunniting and in removing it when the process is completed. That is why maximum deflection of the ducts shall not exceed 90.

At present the device and the method of the flame gunniting of converters is employed for hot patching tar concrete lining of l30-ton capacity oxygen converters. The working part of lance 1 is 7,500 mm long with its external diameter being equal to 108 mm. Ducts 9 of lance l are bended in two planes at right angle to each other: at a 90 angle at the nozzle and at 20 when spaced at a distance of 3,000 mm from the nozzle. By using the above nozzle up to 200 kg/min of the mixture containing the pulverized refractory and the fuel and up to 60 cub.m./min. of oxygen can be supplied to the converter lining.

The device functions as follows.

Upon tapping both the metal and the slag at a temperature of a working surface of a converter lining ranging from l,350 to 1,500 C lance 1 is introduced into converter 14 (FIG.. 1) so that an axis of a straightline portion of lance l coincides with a longitudinal converter axis. In that case nozzle 8 of lance 1 is always tangential to the working surface of converter 14 lining. Depending on the nature of hot patching, nozzle 8 is spaced at a different distance apart from working surface 15 of the lining: at a distance of up to 0.1 of the diameter of converter 14 in continuous gunniting and up to 0.1 0.3 of a converter diameter in gunniting lining sections subjected to local wear.

For flame gunniting the converter linings depending on the nature of repairs and type of the refractory being deposited, use may be made of different refractory materials mixed with solid pulverized fuel. Thus in the continuous gunniting of a tar concrete lining a finely divided (with grain size less than 0.1 mm) mix is utilized consisting of two components: powdered magne site 60-70 percent and pulverized coke 30 40 percent.

To initiate the gunniting process, the supply of the pulverized refractory-fuel mixture and the oxygen supply are simultaneously turned on. The fuel issuing from nozzle 8 mixes with the oxygen, ignites and burns out forming wild high-temperature flame 15. On account of tangential relative to the working surface of converter 14, outflow of the streams containing the mixture of the pulverized refractory with the fuel and the oxygen, flame 15 and flue gases are imparted a rotary in relation to the longitudinal axis of converter 14 motion within the cylindrical cavity of converter 14 (the direction of rotation of flame 15 is indicated with arrows in FIG. 1). In a cross-sectional view of converter 14, the path of rotating gases looks like a series of concentric closed circles. On hitting the lining, particles of the pulverized refractory move over its working surface and on being heated to a plastifying termperature stick to it. Cross-hatched sections in FIG. 1 show gunite 16 in cross-section, built-up to the lining. The particles rebounded from the lining surface are entrained by a flow of rotating gases, driven back to the lining under the action of centrifugal force arising on account of different densities of high-temperature gases and, on establishing again a contact with the working surface of the lining, stick to it in a more remote region.

With lacne l fixed stationary in the course of gunniting, the thickness of a built-up being deposited varies with both the diameter and height of converter 14. Maximum build-up is exhibited in the primary annular zone at the point the flame mates with the converter lining. As a minimum spacing between nozzle 8 and the working surface of the lining increases, the building-up thickness tends also to increase in the primary zone. However when the minimum distance between nozzle 8 and the lining working surface exceeds 0.3 of an internal diametrer of converter 14, intensity of rotation of flame l5 dusted with the pulverized refractory decreases abruptly with the quality of combustion deteriorating also. This results in a substantial carry away of the pulverized refractory and in a lower gunite quality. That is why in gunniting lining zones subjected to local wear nozzle 8 shall be located at a distance of not over than 0.3 of the converter internal diameter from the working surface of the lining. In continuous gunniting, nozzle 8 is imparted, with the aid of manipulator 2, a rotary motion in relation to a longitudinal axis of converter 14 and with the aid of self-propelled truck 3 an intermitent reciprocating movement. Maximum gunite build-up is progressively displaced at that both along the diameter and the height of converter 14 which allows producing a uniform in thickness gunite throughout the worn converter lining.

The proposed invention ensures high technical and economical characteristics, which have been proved by long-term trials of the method of the invention both of experimental tigs and on a production-scale. In the course of mastering the proposed method and device for the flame gunniting of converter linings an increase in lining service life has been achieved: by heats in gunniting tar concrete refractories and by 50 heats in gunniting magnesite refractories in a constant lining layer. Specific consumption of the pulverized refractory-fuel mixture per 1 ton of steel melted during the operating period of a gunnited converter was equal respectively to 0.8 kg/ton and 1.6 kg/ton. Converter downtime per each gunniting operation is 25 min. with the consumption of the pulverized refractory-fuel mixture equalling 5 tons at the above interval.

Flame gunniting by the application of the above method makes it possible to reliably and effectively smear lining zones subjected to local burnout at the end of a compaign and to preclude practically completely premature shutdown of a unit for lining replacement. This will allow planning, a month schedule of cold repairs in a converter shop depending on maximum lining durability.

What is claimed is:

1. A device for deposition of refractory material on linings of a symmetric converter by the cyclone method comprising a concentrically arranged ducting for conveying pulverized refractory material and fuel to a nozzle mounted at one end of said ducting which ducting 6 has a substantially straight main portion for extending being disposed with its axis substantially perpendicular along the longitudinal max of the converter and a furto that of Said further portion and to a plane common ther portion extending from the main portion at an angle of substantially to 90 to the main portion, the nozzle communicating with said further portion and 5 to said main portion and said further portion.

Claims (1)

1. A device for deposition of refractory material on linings of a symmetric converter by the cyclone method comprising a concentrically arranged ducting fOr conveying pulverized refractory material and fuel to a nozzle mounted at one end of said ducting, which ducting has a substantially straight main portion for extending along the longitudinal axix of the converter and a further portion extending from the main portion at an angle of substantially 15* to 90* to the main portion, the nozzle communicating with said further portion and being disposed with its axis substantially perpendicular to that of said further portion and to a plane common to said main portion and said further portion.

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