US3182983A

US3182983A - Air-tight sealing device for the top of a blast furnace

Info

Publication number: US3182983A
Application number: US187464A
Authority: US
Inventors: Tsujihata Keiji; Sawada Yasuhiro
Original assignee: Yawata Iron and Steel Co Ltd
Current assignee: Yawata Iron and Steel Co Ltd
Priority date: 1961-04-18
Filing date: 1962-04-12
Publication date: 1965-05-11
Anticipated expiration: 1982-05-11
Also published as: GB1003956A; DE1433388A1

Description

y 1965 KEIJI TSUJIHATA ETAL 3,182,983

AIR-TIGHT SEALING DEVICE FOR THE TOP OF A BLAST FURNACE 2 Sheets-Sheet 1 Filed April 12, 1962 FIG.2

Rd. 0 P TU mm z www 73 m NM 8 y 1965 KEIJI TSUJIHATA ETAL 3,182,983

AIR-TIGHT SEALING DEVICE FOR THE TOP OF A BLAST FURNACE Filed April 12, 1962 2 Sheets-Sheet 2 FIG.3

INVEN TOR.

jw M

my wn United States Patent 3,182,983 Am-TIGHT SEALING DEVICE FOR TIE Till OF A BLAST FURNACE Keiji Tsujihata, Yawata, and Yasuhiro Sawada, Kokura, Japan, assignors to Yawata Iron & Steel (30., Ltd., Tokyo, Japan Filed Apr. 12, 1962, Ser. No. 187,464 Claims priority, application Japan, Apr. 18, 1961,

7 Claims. (Cl. 266-27) This invention relates to an air-tight sealing device in a cone in the top of a blast furnace.

It is a well known fact that a high pressure operating method has been adopted in a blast furnace to reduce the diiference between the blast pressure and the furnace top pressure by increasing the furnace top gas pressure and that, as a result, there have been produced advantages (1) That the solution loss is reduced by reducing the moving velocity of the gas,

(2) That the amount of production is increased and at the same time the consumption of coke is decreased and (3) That the amount of discharge of the furnace top dust is reduced.

The high pressure operation has been recently adopted as a new technique and is being studied and investigated in various countries. a

The conventional charging device used in a blast furnace consists of a primary charging device comprising a small charging cone provided in the furnace top, a rotary hopper having said small cone as a bottom and a rotating device for said rotary hopper and a secondary charging device comprising a large charging cone provided below said primary charging device and a charging hopper having said large cone as a bottom.

In such charging device, the contact parts of the large charging cone and the side wall of the hopper must be always kept air-tight except at the time of charging. But, however precisely the said air-tight parts might be worked of a special hard material in manufacturing them (it is reported to work them at intervals of 0.2 to 0.3 mm. in the Soviet Union), it will be impossible to make such parts durable for several years. For example, it is reported that, when they were operated at a furnace top pressure of 1.5 atmospheres in blast furnaces in Cherepovetz Metallurgical Factory and Ilitch Factory in the Soviet Union, their period of duration was one year.

From the above fact, it is known that the initial wear will be caused by the friction of the charge, the high pressure gas will jet out through the worn clearance and the wear will be accelerated by the dust contained in the blast furnace gas. For example, in a blast furnace having a pig-iron producing capacity of 1,000 tons/day, the .amount of the charged raw material treated with the charging device for one year is about 750,000 tons excepting the amount corresponding to the interruption of the charge due to the stop of the blast and the like, and the wear of the air-tight parts by the charge can not be neglected. However, the furnace top device for. the high pressure operation in various other countries seems to be being studied so as to keep air-tightness only in the airtight parts subjected to Wear by the charge. Therefore, though it is a well known'fact as described above that it is very advantageous tooperate the blast furnace at a high pressure, the air-tight parts are so imperfect that there are very few furnaces which keep the operation at a high pressure over a long period and further very many problems on the maintenance still remain unsolved.

The present invention relates to an air-tight sealing device which is subjected to greatly reduced wear and interference by the charge so that the problems of the high pressure operation due to such defects as are mentioned above may be solved.

3,182,983 Patented May 11, 1965 Therefore, the effects of using the device of the present invention are (1) That, as the air-tight parts are subjected to very little wear or such interference as impact by ores, the original precision fit of the parts present at the time of manufacturing them can be kept for a long time and (2) That, as the contact area of the air-tight parts is large and the parts are subjected to minimal wear by the charge, such soft convex packing as of brass or special bronze can be fitted, the precise contact with the large charging cone can be made easier and the air-tight effect can be obtained.

The air-tight parts of the charging device in the furnace top which used to be of a life of about one year, whatever hardening method might be used, are thereby durable for a much longer period. Thus, the present invention will contribute much to the progress of the technique of the high pressure operation.

The accompanying drawings shall be briefly explained.

FIGURE 1 is a partly sectioned side view of a conventionally used furnace top charging device.

FIGURE 2 is a partly sectioned side view showing the general construction of the device of the present inventlon.

FIGURE 3 is a partly sectioned side view showing the details of a large charging cone part.

FIGURE 4 is a partly sectioned side view showing the large charging cone part as half opened.

FIGURE 5 is a partly sectioned side view showing the large charging cone part as full opened.

An embodiment of the present invention shall be explained with reference to the drawings.

The charging device used in a conventional blast furnace of the normal pressure is of such construction as is illustrated in FIGURE 1 and consists of a primary charging device comprising a small charging cone 1 provided in the furnace top, a rotary hopper 7 having said small cone as a bottom and a rotating device 4 for said rotary hopper 7. and a secondary charging device comprising a large charging cone 2 provided below said primary charging device and a charging hopper 3 having said large cone as a bottom. The contact parts of the large charging cone 2 and the side wall of the hopper 3 consists of air-tight parts 6, 5 is a blast furnace, and 17 a charge.

The operation of the conventional device shall be described. The raw material 17 with which the rotary hopper 7 is charged will be cut out when the small chargmg cone 1 is opened. When a specified amount of the charge is reached, the large charging cone 2 will be opened and the furnace will be charged with the raw material 1'7. 8 is an imaginary line showing the position of the charging cone 2 as opened. When the above described charging step is considered with reference to FIG- URE 1, it will be known that the charge .willalways pass through the air-tight contact parts 6 of the charging hopper 3 'and the large charging cone 2. Therefore, however precisely they may be worked of a special hard material, it will be substantially impossible to make them durable for several years. V

In the present invention, as illustrated in FIGURE 2,

1 1 is a rotary hopper for a primary charging device provided in a furnace top. 10 is a rotating device for driving the rotary hopper. 9 is a small charging cone forming the bottom of the hopper 11. 12 is a suspending rod for the small charging cone. A hood 13 is provided to project inward in the intermediate part of the side wall of the hopper 11. A recess 13' is made on the whole periphery on the lower inside of the hood 13. The lower end part of the hopper 11 is made an outer contact ring 15 in close contact with an air-tight inner contact ring 16 provided on the lower outer periphery of the small charging cone 9. 14 is a protective metal fixture for the outer contact ring 15, is bent outward at the upper end and is bent inward or provided with a receiving part at the lower end. The bent part at the upper end is vertically movably fitted in said recess. The fitting of the protective metal fixture 14 for the outer contact ring 15 is not to be limited to the above mentioned embodiment but said recess 13' may be made a proper guide mechanism.

The secondary charging device is of the same mechanism as the above described primary charging device, but shall be further detailed in the following.

18 is a hopper to contain one charge. A hood 30 is projected inward on the whole periphery in the intermediate part of the side wall of the hopper 18. A recess 25' is made on the whole periphery on the lower inside of the hood 30. The inside of the lower end part of the side wall of the hopper forms an air-tight outer contact ring 25. This embodiment is an example of the construction of the present invention. Grooves are made on the whole periphery of the contact part. Soft packings 27 such as of brass etc. are fitted in the grooves. Slits 26 and 26' partitioned by the packings 27 become an airtight sealing device of a labyrinth structure and are effective. 31 is a gas inlet pipe opening at one end in the

slit

26 or 26, but is not essential to the present invention. Steam or blast furnace gas is introduced into the gas inlet pipe so as to balance the pressure in the labyrinth part with the pressure within the furnace.

The above described recess 25' made in the side Wall of the hopper 18 may be of such guide mechanism as is mentioned on the primary charging device.

19 is a large charging cone and is vertically movably suspended by a rod 23 so as to form the bottom of the hopper 18. 20 is an air-tight inner contact ring provided on the whole periphery at the lower end of the large charging cone 19. The outer periphery of said air-tight inner contact ring 20 will come into close internal contact with said air-tight outer contact ring 25 when the charging cone 19 is slung up. It is desirable that said airtight inner contact ring 20 and outer contact ring 25 are properly arcuated in cross-section. 21 is a hood provided above the air-tight inner contact ring 20 and is so projected as not to interfere with the vertical movement of the large charging cone 19. 21' is a recess formed between the hood 21 and the charging cone 19 inside the hood 21 so as to be an ore retainer and to prevent the wear of the hood 21 from being caused by ores directly flowing down. However, this protective means is not limited to this embodiment.

24 is a protective cylinder for the air-tight contact parts, is bent outward or provided with a projection outward in the upper end part and is vertically movably fitted in the recess 25' of the hopper 18. The bent part of the protective cylinder 24 is vertically movable over the length of the recess 25 within the recess. In order to prevent the wear of the protective cylinder from being caused by the charge flowing down, it is possible to provide an ore retainer 22 inside the lower end of the cylinder. 28 is a blast furnace body. 29 is a charged ore receiving metal fixture. is the interior of the furnace.

The construction of the present invention is as described above. The operation, for example, of the large charging cone (that of the small charging cone being the same) shall be explained in detail with reference to the drawings. As shown in FIGURE 3, the large charging cone 19 is slung up with the large charging cone suspending rod 23 and the movable protective cylinder 24 is thereby pushed up so that perfect air-tightness may be kept by the airtight inner contact ring 20 and outer contact ring 25. The air-tight outer contact ring 25 has

slits

26 and 26 acting as a labyrinth packing and high pressure steam is fed to the slit 26 through a steam pipe 31 as indicated by the arrow 32 so that the pressure Within the furnace and the pressure within the slit 26 may be balanced with each other and gas leakage out of the furnace may be prevented and therefore the air-tightness may be better kept. The slit 26' is an application of the principle of the known labyrinth packing, is not essential to the present invention and may be considered to be a slit formed by the convex packing 27 made of brass or special bronze.

Now, there shall be explained the case that the charging hopper 18 is full of the charged raw material and the large charging cone 19 is lowered to charge the furnace with the raw material. As shown in FIGURE 4, as the large charging cone 19 lowers, the movable protective cylinder 24 will also lower due to its own weight by the range of the recess in the side wall part of the hopper 18 and will shelter the inner surface of the air-tight outer contact ring so that the ores may not run against the air-tight parts. Further, only the large charging cone 19 will continue to lower and the charge will be fed into the furnace while sliding between an ore retaining shelf 22 to protect the lower end of the movable protective cylinder 24 and an ore retaining shelf 21' fixed to the lower end of the large charging cone to protect the air-tight inner contact ring 20. In such case, as the charged ores will be fed in the direction indicated by the arrows as shown in FZGURE 5, the charge will not run against the air-tight parts of the air-tight inner contact ring 20 and outer ring 25. In such process, the large charging cone will lower and the furnace will be charged with the raw material in the charging hopper 18. In the process of raising and sealing the large charging cone 19, the movable protective cylinder 24 is pushed up as in FIGURE 4 by the ore retaining shelf 21 or the cone part of the large charging cone 19 so as to be in such state as is shown in FIGURE 3 and to keep perfect air-tightness.

What we claim is:

1. An air-tight charging and sealing device for the top of a blast furnace, comprising a small charging cone and a large charging cone below said small charging cone, the large charging cone having a hood adapted to be mounted on the wall of the furnace body and on which said small charging cone is mounted, said hood projecting inwardly into the furnace body, and the smaller charging cone having a hood mounted on the top of the hood of said large charging cone, each charging cone comprising an air tight outer contact ring member fixed on the lower end of the hood, said outer contact ring member having a sealing surface on the lower end of the inside surface thereof, a cone member, an inner contact ring on the outer surface of the lower part of said cone member, said outer ring member sealing surface and the inner ring being engageable in air-tight sealing engagement when the cone memher is pulled up, said outer contact ring member having an annular recess in the inside surface thereof between the sealing surface and said hood, a protective cylinder having an outwardly bent upper end positioned within said outer sealing ring and having the outwardly bent upper end freely slidable in the recess in the axial direction of said outer ring member, said protective cylinder moving downwardly over the sealing surface of said outer ring when said cone member is lowered, and an ore retaining shelf on said cone member immediately above said inner contact ring for diverting ore material sliding down said cone member outwardly away from said inner contact ring.

2. A charging and sealing device as claimed in claim 1 in which said ore retaining shelf comprises a ring member which projects upwardly from said cone member and forms a small pocket between the inside surface of said ring and the surface of said cone member, whereby when ore slides down said cone member it collects in said pocket and at least partially protects said ring member from wear.

3. A charging and sealing device as claimed in claim 2 in which said protective cylinder has an inwardly and upwardly bent portion on the lower end thereof forming an upwardly open pocket, whereby when ore strikes said cylinder it collects in said pocket and at least partially protects said cylinder from wear.

4. A charging and sealing device as claimed in claim 2 in which said sealing surface on the outer contact ring member has .a plurality of annular slits therein and means for feeding high pressure gaseous material into said slits for causing said slits to act as a labyrinth packing in cooperation with said inner contact ring.

5. An air-tight charging and sealing device for the top of a blast furnace, comprising a small charging cone and a large charging cone below said small charging cone, the large charging cone having a hood adapted to be mounted on the wall of the furnace body and on which said small charging cone is mounted, said hood projecting inwardly into the furnace body, and the smaller charging cone having a hood mounted on the top of the hood of said large charging cone, said large charging cone comprising an air tight outer contact ring member fixed on the lower end of the hood, said outer contact ring member having a sealing surface on the lower end of the inside surface thereof, a cone member, an inner contact ring on the outer surface of the lower part of said cone member, said outer ring member sealing surface and the inner ring being engageable in air-tight sealing engagement when the cone member is pulled up, said outer contact ring member having an annular recess in the inside'surface' thereof between the sealing surface and said hood, a protective cylinder having an outwardly bent upper end positioned within said outer sealing ring and having the outwardly bent upper end freely slidable in the recess in the axial direction of said outer ring member, said protective cylinder moving downwardly over the sealing surface of said outer ring when said cone member is lowered, and an ore retaining shelf on said cone member immediately above said inner contact ring for diverting ore material sliding down said cone member outwardly away from said inner contact ring.

6. An air-tight charging and sealing device for the top of a blast furnace, comprising a small charging cone and a large charging cone below said small charging cone, the large charging cone having a hood adapted to be mounted on the wall of the furnace body and on which said small charging cone is mounted, said hood projecting inwardly into the furnace body, and the smaller charging cone having a hood mounted on the top of the hood of said large charging cone, said small charging cone comprising an air tight outer contact ring member fixed on the lower end of the hood, said outer contact ring member having a sealing surface on the lower end of the inside surface thereof, a cone member, an inner contact ring on the outer surface of the lower part of said cone member, said outer ring member sealing surface and the inner ring being engageable in air-tight sealing engagement when the cone member is pulled up, said outer contact ring member having annular recess in the inside surface thereof between the sealing surface and said hood, a protective cylinder having an outwardly bent upper end position within said outer sealing ring and having the outwardly bent upper end freely slidable in the recess in the axial direction of said outer ring member, said protective cylinder moving downwardly over the sealing surface of said outer ring when said cone member is lowered, and an ore retaining shelf on said cone member immediately above said inner contact ring for diverting ore material sliding down said cone member outwardly away from said inner contact ring.

7. An air-tight sealing device for the top of a blast furnace having a charging cone with a hood adapted to be mounted on the wall of the furnace body, the hood projecting inwardly into the furnace body, and the charging cone having a cone member, said sealing device compris ing an air tight outer contact ring member adapted to be fixed on the lower end of the hood, said outer contact ring member having a sealing surface on the lower end of the inside surface thereof, an inner contact ring adapted to be mounted on the outer surface of the lower part of said cone member, said outer ring member sealing surface and the inner ring being engageable in air-tight sealing engagement when the cone member is pulled up, said outer contact ring member having an annular recess in the inside surface thereof between the sealing surface and said hood, a protective cyiinder having an outwardly bent upper end positioned within said outer sealing ring and having the outwardly bent upper end freely slidable in the recess in the axial direction of said outer ring member, said protective cylinder moving downwardly over the sealing surface of said outer ring when said cone member is lowered, and an ore retaining shelf adapted to be mounted on said cone member immediately above said inner contact ring for diverting ore material sliding down said cone member outwardly away from said inner contact ring.

References Cited by the Examiner FOREIGN PATENTS 671,726 2/39 Germany. 679,479 8/ 39 Germany. 145,938 6/54 Sweden.

MGRRIS O. WOLK, Primary Examiner.

Claims

7. AN AIR-TIGHT SEALING DEVICE FOR THE TOP OF A BLAST FURNACE HAVING A CHARGING CONE WITH A HOOD ADAPTED TO BE MOUNTED ON THE WALL OF THE FURNACE BODY, THE HOOD PROJECTING INWARDLY INTO THE FURNACE BODY, AND THE CHARGING CONE HAVING A CONE MEMBER, SAID SEALING DEVICE COMPRISING ING AN AIR TIGHT OUTER CONTACT RING MEMBER ADAPTED TO BE FIXED ON THE LOWER END OF THE HOOD, SAID OUTER CONTACT RING MEMBER HAVING A SEALING SURFACE ON THE LOWER END OF THE INSIDE SURFACE THEREOF, AN INNER CONTACT RING ADAPTED TO BE MOUNTED ON THE OUTER SURFACE OF THE LOWER PART OF SAID CONE MEMBER, SAID OUTER RING MEMBER SEALING SURFACE AND THE INNER RING BEING ENGAGEABLE IN AIR-TIGHT SEALING ENGAGEMENT WHEN THE CONE MEMBER IS PULLED UP, SAID OUTER