US3722814A

US3722814A - Method of blowing such fluid as reducing gas into a furnace

Info

Publication number: US3722814A
Application number: US00113862A
Authority: US
Inventors: T Miyashita
Original assignee: Nippon Kokan Ltd
Current assignee: JFE Engineering Corp
Priority date: 1970-02-13
Filing date: 1971-02-09
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27
Also published as: CA939506A; JPS497283B1; BE762896A; DE2106122B2; GB1311050A; FR2078550A5; DE2106122A1

Abstract

A method and apparatus for (a) injecting fluids, particularly reducing gases, through a tuyere into an operating furnace, and (b) safely cleaning out plugged tuyeres, in which a seal is provided in the tuyere so that a back pressure in excess of the furnace pressure can be developed. A rotatable borer is provided forwardly of the seal to remove solids plugging the tuyere. The seal and the borer are coaxially mounted on a retractable shaft so that they can be simultaneously withdrawn and fluid injection resumed immediately the tuyere is cleaned.

Description

Unite States tent 1 Miyasliita METHOD OF BLOWING SUCH FLUlD AS REDUCING GAS INTO A FURNACE [75] Inventor:

[73] Assignee: Nippon Kokan Kabushiki Kaisha,

Tokyo,Japan 221 Filed: Feb.9, 1971 21 Appl.No.: 113,862

Tsuneo Miyashita, Kawasaki, Japan [30] Foreign Application Priority Data Feb. 13,1970 Japan ..45/l2l47 [52] U.S.Cl. ..239/1, 239/117, 239/1323, 266/42 [51] Int. Cl. ..B05b 15/02 [58] Field of Search ..266/41,'42; 239/1, 106, 114, 239/115, 116,117, 132,132.l, 132.3

[56] References Cited UNITED STATES PATENTS 2,244,079 6/1941 Phillips. ..266/42 1 Mar. 27, 1973 Drackley 266/42 X Holmes ..266/42 X Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Michael Mar AttorneyFlynn & Frishauf [57] ABSTRACT A method and apparatus for (a) injecting fluids, particularly reducing gases, through a tuyere into an operating furnace, and (b) safely cleaning out plugged tuyeres, in which a seal is provided in the tuyere so that a back pressure in excess of the furnace pressure can be developed. A rotatable borer is provided forwardly of the seal to remove solids plugging the tuyere. The seal and the borer are coakially mounted on a retractable shaft so that they can be simultaneously withdrawn and fluid injection resumed immediately the tuyere is cleaned.

3 Claims, 3 Drawing Figures METHOD OF BLOWING SUCH FLUID AS REDUCING GAS INTO A FURNACE This invention relates to a method of cleaning blocked tuyeres and blowing fluids such as reducing gases into a furnace and a boring device for use therein.

Recently, blowing of reducing gas or other fluids into a furnace or other operation under high pressure has come to require a safe and secure method of blowing such reducing gas through nozzles into the furnace, usually a shaft furnace, in which materials are contained and the inner pressure of which is higher than that of the atmosphere, without interfering with operation. According to prior art methods, when a tuyere of a nozzle is blocked up with solid material in the furnace, the solid material is removed by driving a metal rod into the solid material with a hammer in order to punch a hole and let air into the furnace or by inserting an iron pipe through which oxygen is supplied and burnt to make a hole in the clogged material in the tuyeres to let air into the furnace. Such prior methods are not without disadvantages, for example, the former method requires the operations to be interrupted due to clogging of nozzles, and with the latter method, it is impossible to conduct the same when high-temperature reducing gas is being blown into a furnace because the operation is not safe.

In order to eliminate such drawbacks of the prior methods, it is an object of the present invention to provide a method of cleaning tuyeres and blowing such fluids as reducing gas into a furnace, characterized in that material clogging the inside or front of a nozzle or solid material floating therein is removed by making a hole therein with a boring apparatus equipped with an integral nozzle. The nozzle of the boring apparatus is provided with fluid at a higher pressure than that within the furnace in order to prevent materials or gas in the furnace from flowing back to the nozzle, and then said fluid is blown into the furnace.

Another object of the present invention is to provide a boring apparatus for use in the method of cleaning tuyeres and blowing such fluids as reducing gas into a furnace, comprising: a driving tube to which a sealing valve for a tuyere is fixed and which tube is longitudinally movable in a nozzle which is equipped with a cooling device; a boring shaft, longitudinally movable and rotatable, inserted in the said driving tube; and a boring means mounted at the end of the said boring shaft in such a way as to be projected forwardly of the sealing valve.

The present invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a longitudinal section of a boring apparatus for use in the method of the present invention, a part of which is omitted;

FIG. 2 is a cross-sectional view of the boring apparatus shown in FIG. 1 taken along the line A-A; and

FIG. 3 is an enlarged section of the rear seal shown in FIG. 1.

The boring apparatus of the present invention is provided with a nozzle 1, pipes 2 for supplying and draining water provided around the inner circumference of the nozzle to cool the nozzle as required, a tuyere 3 at the end of the nozzle in such a way as to be projected forwardly therefrom, and pipes 4 for supplying and draining water which are provided in the tuyere 3 and connected to the pipes 2 to cool the tuyere.

Water-supplying pipe 5 to supply the pipes 2 in the nozzle 1 with water and a drainage pipe 6 to drain water from the same are provided at the rear part of the nozzle 1.

A sealing valve 8 for the tuyere 3 of the nozzle 1 is fixed to the end of a driving tube 7 and a driving means 9 provided at the rear part of the nozzle 1 is connected to the driving tube 7. The driving tube 7 is set in longitudinal motion in the nozzle 1 by the driving means 9 to automatically shut or open the tuyere 3 of the nozzle 1 with the sealing valve 8. A boring shaft 10 to which a boring means 11 is fixed is inserted in the driving tube 7 in such a way as to be projected forwardly through the sealing valve 8 and connected at the rear end thereof to the driving means 9. The boring shaft 10 is arranged in such a way as to be longitudinally movable and rotatable independently of the motion of the driving tube 7 after the tuyere 3 is shut with the sealing valve 8 by means of the forward motion of the driving tube 7.

O-shaped rings 12 are provided in the seal at the rear end of the nozzle 1 and a packing 13 is interposed between the driving tube and the threaded part of a tightening cap 14. The nozzle 1 is provided with a lining 15 around the inner circumference thereof and an opening 16 for blowing fluid into the nozzle 1. l7 denotes a furnace body and 18 a material stuck to the wall of the furnace.

The method of blowing fluid into a furnace by utilizing the above-described boring apparatus will be described hereinafter, reference being made to the accompanying drawings.

As shown in FIG. 1, a fluid such as nitrogen gas, air or gas/powder mixtures is blown into the nozzle 1 from the opening 16 to create a back pressure which is higher than that within the furnace against the sealing valve. Then the boring shaft 10 is pushed forward and simultaneously rotated by means of the driving-means 9 to makea hole in the material 18 stuck to the front part of the tuyere 3 of the nozzle 1, thus removing the material 18. After the material stuck to the front part of the tuyere 3 is removed, the driving means 9 is operated to draw back the boring means 11 fixed to the boring shaft 10, and the driving tube 7. Subsequently,

. the sealing valve 8 sealing the tuyere 3 is simultaneously drawn back to leave the tuyere, and fluid begins to flow into the furnace through the nozzle 1.

As'is clear from the foregoing, the present invention facilitates removal of material stuck to the front part of the tuyere 3 of the nozzle 1 or solid materials floating therein by means of the boring apparatus comprised in the nozzle 1 while blowing of fluid into the furnace is stopped temporarily. Moreover, according to the present invention, it is possible not only to prevent removed materials from flowing backward to the nozzle or stopping up the boring shaft but also to completely prevent the materials or gas in the furnace from flowing backward by maintaining a back pressure higher than that-within the furnace against the sealing valve and the inside of the nozzle 1 while the boring operation is conducted. Further, remote control of the boring apparatus facilitates a safe and secure boring operation during operation of the furnace. Consequently, interruption of the furnace operation is not required even when the boring operation must be conducted when a high-temperature reducing gas is blown into the furnace.

The present invention may be applied to any nozzles for blowing fluid into a furnace, e.g. those of blast furnaces, cupolas, shaft reduction furnaces or furnaces of any industrial type. Excellent results can be obtained with any of such nozzles.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of removing solid material from a furnace tuyere through which a fluid is blown into an' operating furnace, comprising: generating a fluid back pressure in said tuyere against a sealing means provided in said tuyere such that said back pressure is greater than the fluid pressure in said furnace, passing a rotatable boring device forwardly through said sealing means, rotating said boring device whereby a hole is bored through said solid material, withdrawing said boring device and said sealing means and blowing said fluid through saidtuyere and said hole into said operating furnace.

2. A method as claimed in claim 1 wherein said fluid is selected from, a reducing gas, nitrogen, air and gas/powder mixtures.

3. A method as claimed in claim 1 wherein said sealing means and said boring device are withdrawn simultaneously on a common longitudinal axis.

Claims

1. A method of removing solid material from a furnace tuyere through which a fluid is blown into an operating furnace, comprising: generating a fluid back pressure in said tuyere against a sealing means provided in said tuyere such that said back pressure is greater than the fluid pressure in said furnace, passing a rotatable boring device forwardly through said sealing means, rotating said boring device whereby a hole is bored through said solid material, withdrawing said boring device and said sealing means and blowing said fluid through said tuyere and said hole into said operating furnace.