US3010711A - Blast furnace bell and bell hopper arrangement - Google Patents

Description

G. J. KRUPA Nov. 28, 1961 BLAST FURNACE BELL AND BELL HOPPER ARRANGEMENT Filed June 24, 1959 2 Sheets-Sheet l m m m w.

ATTORNEY United States Patent O 3,010,711 BLAST FURNACE BELL AND BELL HOPPER ARRANGEMENT George J. Krupa, Levittown, Pa., assignor to United States Steel Corporation, a corporation of New Jersey Filed June 24, 1959, Ser. No. 822,488 7 Claims. (Cl. 266--27) The present invention relates generally to blast furnace equipment and more particularly to an improved seating arrangement between the big bell and the big bell hopper of a blast furnace and the method of forming the improved seating arrangement.

Under normal conditions a blast furnace is in continuous operation for periods of approximately four years. At the end of each period of operation, which is termed a campaign, the furnace is shut down for relining and major repairs. During the course of a campaign the constant abrading effect of the large quantities of stock sliding over the surface of the big bell causes the seat area between the big bell and the big bell hopper to become worn. After such Wear occurs holes form in the seat area between the bell and the hopper so that it is no longer gas-tight around its entire circumference.

Since blast furnaces, particularly high top pressure furnaces, operate with an internal gas pressure greater than atmospheric pressure even a slight hole or leak at the seat between the big bell and the big bell hopper causes a relatively large amount of gas to escape from within the furnace. The escaping gas carries with it particles of ore, coke and sinter which are highly abrasive. The abrading particles carried by the escaping gas cause the holes in the seal to enlarge rapidlyv In high top pressure furnaces this condition occurs after only about two years of operation and it then becomes necessary to shut down the furnace and alleviate the condition with temporary repairs so that the furnace can be operated through the remainder of the campaign. At the end of the campaign the worn bell and hopper can be replaced with new units. This cannot be done during the campaign because it would be necessary to cease op erations completely to effect such replacement. Such an interruption of operations would be extremely costly. In stead, an attempt is made to recondition the seat area while the furnace is ofi-blast. The methods used to thus recondition the bell and hopper of a blast furnace prior to my invention were difiicult and time consuming and more often than not resulted in the formation of an ineffective seat between the bell and the hopper which was not gas-tight.

It is accordingly the primary object of my invention to provide an improved seating arrangement between the large bell and the large bell hopper of a blast furnace and a method of forming such a seating arrangement.

It is another object of the invention to provide a primary seat between the big bell and the big bell hopper of the blast furnace and secondary seats which can be put into use easily and quickly after the primary seat becomes worn.

It is a further object of the invention to provide apparatus of the character indicated in the above object wherein the primary and secondary seats can be formed with precision before installation.

These and other objects will become more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is a vertical sectional view of the upper portion of a blast furnace having a big bell and big bell hopper according to the invention installed therein;

FIGURE 2 is a plan of the big bell and big bell hopper of the invention;

FIGURE 3 is a partial sectional view;

FIGURE 4 is a view similar to FIGURE 3 showing the big bell and big bell hopper of the invention after the secondary seat has been utilized;

FIGURE 5 is a partial view in perspective showing one retaining lug in burned-away condition; and

FIGURE 6 is a view similar to FIGURE 3 showing a modified embodiment of the invention.

Referring more particularly to the drawings reference numeral 2 designates the top of a blast furnace having a big bell 4 and big bell hopper 6 therein arranged in accordance with the invention. The big bell is conventional in structure and is adapted to be raised and lowered in conventional manner to close and open the burden-receiving hopper 6. The bottom portion of the hopper 6 consists of a ring 8 detachably afiixed to the hopper by means of lugs Ill which are spaced circumferentially around the inside of the hopper and the ring. As best shown in FIGURE 5, each lug is welded to the hopper and to the ring and is provided with a slot 12 on its underside which overlies the junction between the ring 8 and the hopper 6.

The bottom of the ring 8 sits upon the hell 4 as at 14 when the bell is raised to close the hopper.

When the seat 14, which may be called the primary seat, becomes worn and no longer provides a gas-tight seal when the bell is in raised position, the ring 8 is welded, as at 16, to the adjacent surface of the bell 4. Then the lugs 19 are burned to separate the portions thereof attached to the hopper and to the ring, as shown by lug 10' in FIGURE 5. The upper surface of the ring 8, which was made an integral part of the big bell 4 by the weld 16, together with the adjacent edge of the hopper 6 forms a new or secondary seat 18. The seat 18 is gas-tight and effective having been made so by machining when the big bell and big bell hopper were constructed and before they were installed in the furnace. In order to insure easy separation between the hopper and the ring after the lugs 10 are burned a gasket 20, made of asbestos, copper or other heat resistant material may be interposed between the ring 8 and the adjacent surface of the hopper when the ring is initially affixed to the hopper during construction.

Provisions for more than one secondary seat can be made by affixing more than one ring to the hopper. FIGURE 6, which shows two rings 8a and 8b afi'ixed to a hopper 6a by lugs liia, illustrates this modified arrangement.

If desired, after the secondary seat has been put into use, a raised surface may be provided on the hell 4 coextensive with the upper surface of the ring 8 by welding plates 22 around the bell as shown in FIGURE 4. The plates form a skirt around the bell extending to a point intermediate the top and bottom thereof. This eliminates the possibility of undesirable stock-damming at the bottom of the bell caused by the ring 8. I

When it becomes necessary to utilize the secondary seat 18 the bell 4 is raised to close the hopper 6 and the furnace is taken olf blast. After the furnace has cooled for a short while a workman enters the top of the furnace through a suitable hatch opening 24 and descends to the surface of the big bell. He welds the ring 8 to the surface of the bell and then cuts the lugs by burning as described above to separate the ring 8 from the hopper 6. Thus the secondary seat, which was precision-machined before the hopper and ring were assembled, can be put into use quickly and easily after the primary seat becomes worn.

While two embodiments of my invention have been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the followingclaims.

I claim: l. A method of forming a primary and a secondary seat between a bell and a bell hopper of a blast furnace which includes interposing a metal ring between the adjacent surfaces of the bell and hopper, detachably affixing the interposed ring to the inner wall of said hopper to form said primary seat between the ring and the bell, then, after said primary seat is Worn, rigidly affixing the ring to said bell and detaching the ring from the inner Wall of said hopper to form said secondary seat between the ring and the hopper.

2. A method as defined by claim 1 including the step of interposing a'gasket of heat-resistant material between the adjacent surfaces of said ring and said hopper before said ring is detachably affixed to the inner wall of said hopper. a

3. A method as defined by claim 1 including the step of providing a raised surface around said bell coextensive with the upper surface of the ring and extending from the ring toward the top of the bell after said ring is rigidly attached to said bell .and detached from the inner wall of said hopper.

4. In a blast furnace the combination comprising a bell, a bell hopper for receiving the furnace burden, said hopper being open at the bottom and adapted to be closed by said bell, a metal ring interposed between the adjacent surfaces of the 'bell and the hopper, means detachably affixing said interposed ring to the inner wall of said hopper to form a primary seat between said ring and said bell, said ring being adapted to be rigidly affixed to said bell and detached from the inner wall of said hopper to form a secondary seat between said ring and said hopper upon wear of said primary seat.

5. In a blast furnace the combination as defined by claim 4 in which said means detachably afiixing said ring to the inner surface of said hopper include a plurality of lugs spaced around the inner surface of said hopper and the adjacent surface of said ring, each of said lugs extending across the junction between said ring and said hopper and being welded to said ring and said hopper, respectively, each of said lugs having a transverse groove in the nndersurface thereof overlying the junction between said ring and saidhopper whereby the lug can be severed to detach said ring from said hopper.

6. In a blast furnace the combination as defined by claim 4 including a gasket of heat-resistant material intel-posed between the ring and the hopper.

7. In a blast furnace the combination comprising a bell, a bell hopper for receiving the furnace burden, said hopper being open at the bottom and adapted to be closed by said bell, a metal ring interposed between the adjacent surfaces of the bell and hopper, means rigidly affixing said ring to said bell, and a raised surface on said bell coextensive with the upper surface of the ring and extending substantially from the ring to the top of the bell.

References Cited in the file of this patent mi -r "a. R a

Images