US3911175A

US3911175A - Method and a device for gunniting converter

Info

Publication number: US3911175A
Application number: US485598A
Authority: US
Inventors: Oleg Nikolaevich Chemeris; Evgeny Vasilievich Tretyakov; Viktor Kirillovich Didkovsky; Vilen Davidovich Kanfer; Nikolai Konstantinov Paschenko; Izmail Grigorievich Zeltser; Girgory Mikhailovich Ljukimson; Alexandr Nikolaevich Bashkatov; Boris Nikolaevich Melnikov; Miron Yakovlevic Medzhibozhsky; Ilya Alexandrovich Goldberg; Izrail Abramovich Juzefovsky; Rafail Davidovich Ratmansky; Viktor Nikolaevich Irkha; Jury Nikolaevich Borisov; Fedor Filippovich Kurochkin
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-01-28
Filing date: 1974-07-03
Publication date: 1975-10-07
Anticipated expiration: 1992-10-07

Abstract

A method of flame gunniting a converter comprises the steps of dusting the flame with a pulverized refractory, imparting the flame the rotational movement which is relative to the longitudinal axis of the converter after the flame has been dusted with the pulverized refractory, and directing the flame tangentially to a cylindrical working surface of the converter.

Description

United States Patent [191 Chemeris et a].

[451 Oct. 7, 1975 Inventors: Oleg Nikolaevich Chemeris, bulvar Mira, 18, kv. 69; Evgeny Vasilievich Tretyakov, ulitsa Rozy Ljuxemburg, 30, kv. 32; Viktor Kirillovich Didkovsky, ulitsa Rozy Ljuxemburg, 30a, kv. 42; Vilen Davidovich Kanfer, ulitsa Tsusimskaya, 63, kv. 17, all of Donetsk; Nikolai Konstantinovich Paschenko, ulitsa Makara Mazaya, 74, kv. l, Zhdanov Donetskoi oblasti; lzmail Grigorievich Zeltser, prospekt Nakhimova, 154, kv. 29, Zhdanov Donetskoi oblasti; Girgory Mikhailovich Ljukimson, prospekt Lenina, 45, kv. l0, Zhdanov Donetskoi oblasti; Alexandr Nikolaevich Bashkatov, poselok Ukraina, pereulok Sadkovy, 70, 72, Zhdanov Donetskoi oblasti; Boris Nikolaevich Melnikov, ulitsa Sechenova, 68, kv. 27, Zhdanov Donetskoi oblasti; Miron Yakovlevich Medzhibozhsky, perculok Nakhimova, 5, kv. 26, Zhdanov Donetskoi oblasti; llya Alexandrovich Goldberg, ulitsa Shaumiana, 47, kv. 35, Leningrad; lzrail Abramovich Juzefovsky, ulitsa Reshetova, 5, kv. 55, Leningrad; Rafail Davidovich Ratmansky, ulitsa llicha, 52, kv. 53, Zhdanov Donetskoi oblasti; Viktor Nikolaevich Irkha, ulitsa Sechenova, 68, kv 48, Zhdanov Donetskoi oblasti; Jury Nikolaevich Borisov, prospekt Sovetskoi Armii, 16, kv. l3, Novokuznetsk Kemerovskoi oblasti; Fedor Filippovich Kurochkin, prospekt Nakhimova, 154, kv. 33, Zhdanov Donetskoi oblasti, all of U.S.S.R.

22 Filed: July 3,1974

21 App]. No.: 485,598

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

[52] US. Cl. 427/233; 118/47; 118/302; 219/121 P; 427/423; 264/270 [51] Int. CL B05B 7/20 [58] Field of Search 117/46 FS, 46 FZ, 95, 96,

117/105.2, 105.4, 93.1 PF; 118/47, 302; 264/270; 427/233, 423; 219/121 P Primary Examiner-Michael Sofocleous Attorney, Agent, or Firm-Holman & Stern [57 ABSTRACT A method of flame gunniting a converter comprises the steps of dusting the flame with a pulverized refractory, imparting the flame the rotational movement which is relative to the longitudinal axis of the converter after the flame has been dusted with the pulverized refractory, and directing the flame tangentially to a cylindrical working surface of the converter.

1 Claim, 2 Drawing Figures US. Patent Oct. 7,1975 3,911,175

METHOD AND A DEVICE FOR GUNNITING CONVERTER This is a continuation of application Scr. No. 221,655, filed Jan. 28, 1972, now abandoned.

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

PRIOR ART GENERALLY 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 gunnite 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 gunnite to produce ceramic bonds between the grains of a highly refractory constituent of the gunnite; 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.

A method of gunniting the converter lining with the aid of a fuel-oxygen torch shooting a pulverized refractory fed into its flame is widely known.

With the flame gunniting method, the above disadvantages are practically completely avoided. As to the quality aspects of the gunnite, 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 gunnite produced becomes self-supporting 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 or low yield (gunning efficiency is a weight ratio of a gunnite built-up to the lining zone under repair to that of a refractory gunnite constituent fed to a repair zone). In that case, the gunning efficiency or yield is usually equal to -20% but not in excess of 40%.

It is an object of the present invention to develop a method for gunniting converter linings and a device for doing the same, which would substantially increase efficiency of gunniting, enable the production of a slagand heat-resistant gunnite containing basic refractories, tar concretes among them, avoid the loss of usable time in gunnite burning and preclude the possibility of thermal spalling of the refractory lining during repairs.

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

In order to place 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.

BRIEF DESCRIPTION OF THE DRAWINGS In order to make the nature of the present invention more fully apparent an exemplary embodiment of the proposed device is described below, which is to be considered with due reference to the accompanying drawings, in which:

FIG. 1 shows a converter and a gunniting device, conforming to this invention; and

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

DETAILED DESCRIPTION OF THE 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. 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 I over a shop working floor and for imparting to 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 l2 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 15-90 in a plane perpendicular to the nozzle axis.

For continuous gunniting, the axis of nozzle 8 must 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 dot-and-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 it is impractical to make the 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 l5-90, 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 must 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 powderfuel 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 to gunniting and in removing it when the process is completed. That is why maximum deflection of the ducts must 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 l is 7,500 mm long, with its external diameter being equal to 108 mm. Ducts 9 of lance 1 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.lmin. 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 1,350 to l,500C, lance 1 is introduced into converter 14 (FIG. 1) so that an axis of a straightline portion of lance 1 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 of the lining: at a distance of up to 0.1 of the radius of converter 14, in continuous gunniting, and up to 0.1 0.3 of a converter radius 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 magnesite 6070% and pulverized coke 3O 40%.

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 position of the nozzle 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 l5 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 temperature stick to it. Crosshatched sections in FIG. 1 show gunnite 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 hightemperature gases and, on establishing again a contact with the working surface of the lining, stick to it in a more remote region.

With lance l fixed stationary in the coarse of gunniting, the thickness of a built-up being deposited varies with both the diameter and height of converter 14. Maximum buildup 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 radius 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 gunnite qual ity. That is why in gunniting lining zones subjected to local wear nozzle 8 must be located at a distance of not over than 0.3 of the converter internal radius 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 l4, and with the aid of self-propelled truck 3, an intermitent reciprocating movement. Maximum gunnite build-up is progressively displaced at both along the diameter and the height of converter 14 which allows production of a uniform in thickness gunnite 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 was 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 campaign 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 surface of a converter;

the relative rotation between the cylindrical working surface of the converter and the angle of the flame substantially tangent thereto and continuously flame spraying gunnite in a path of rotating gases so that the plastified material adheres to the cylindrical surface and portions of the material which rebound from the cylindrical working surface are driven back onto the cylindrical surface under centrifugal forces of the flue gases of the

Claims

1. A METHOD OF FLAME SPRAYING GUNNITE ON THE INTERIOR CYLINDRICAL SURFACE OF A CONVERTER, SAID METHOD COMPRISING THE STEPS OF: A. PROVIDING AN INTERIOR CYLINDRICAL WORKING SURFACE OF A CONVERTER, B. DUSTING A FLAME WITH A PULVERIZED REFRACTORY TO PROVIDE A PLASTIFIED MATERIAL TO BE COATEDONTO THE INTERIOR CYLINDRICAL WORKING SURFACE, C. IMPARTING TO THE FLAME CONTAINING THE PLASTIFIED MATERIAL A ROTATIONAL MOVEMENT RELATIVE TO THE LONGITUDINAL AXIS OF THE CYLINDRICAL SURFACE OF THE CONVERTER AFTER THE FLAME HAS BEEN DUSTED WITH THE PULVERIZED REFRACTORY, AND D. DIRECTING THE TANGENTIALLY WITH THE PLASTIFIED MATERIAL ENTRAINED THEREIN TO THE INTERIOR CYLINDRICAL WORKING SURFACE OF THE CONVERTER BY CONTROLLING THE RELATIVE ROTATION BETWEEN THE CYLINDRICAL WORKING SURFACE OF THE CONVERTER AND THE ANGLE OF THE FLAME SUBSTANTIALLY TANGENT THERETO AND CONTINUOUSLY FLAME SPRAYING GUNNITE IN A PATH OF ROTATING GASES SO THAT THE PLASTIFIED MATERIAL ADHERES TO THE CYLINDRICAL SURFACE AND PORTIONS OF THE MATERIAL WHICH REBOUND FROM THE CYLINDRICAL WORKING SURFACE ARE DRIVEN BACK ONTO THE CYLINDRICAL SURFACE UNDER CENTRIFUGAL FORCES OF THE FLUE GASES OF THE FLAME.