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Patent Searching and Data


Title:
TOOLING FOR CHANGING TUYÈRES AND COOLING BOXES
Document Type and Number:
WIPO Patent Application WO/2008/011694
Kind Code:
A1
Abstract:
The concerned subject-matter discloses a set of disassembling, portable devices which can be operated under low operating expense and high security standards, used for the removal of the tuyeres and the cooling boxes of a blast furnace by means of a hydraulic jack. The simple and robust construction consists of a rebound (18), a longitudinal rectangular bar (13 A), a containment bolt (28), a supporting bar (21 ) with window (22), a cradle (23), a drawer (24) with a hole (26), wheel bores (27), a counter-cradle (25), a positioning bar (16) with wedge (17), a terminal (29), a hydraulic jack (33), a longitudinal bar (13), a drawer device (30) and a whirl bar (34).

Inventors:
COSTA WARLEY PATRICK DE MIRAND (BR)
FILHO ANTONIO MARCIANO VIEIRA (BR)
GOMES JOAQUIM FERREIRA (BR)
Application Number:
BR2007/000036
Publication Date:
January 31, 2008
Filing Date:
February 07, 2007
Export Citation:
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Assignee:
GERDAU ACOMINAS S A (BR)
International Classes:
C21B7/16; F27B1/10; F27D1/16; F27D25/00
Foreign References:
JPH03153809A1991-07-01
US5203063A1993-04-20
US5925312A1999-07-20
JPS60243208A1985-12-03
Attorney, Agent or Firm:
PANZERA, Carlos Eduardo Evangelista (Km 07 Fazenda do Cadet, Ouro Branco MG- Brazil- 000, BR)
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Claims:

C L A I M S

1. "TOOLING FOR CHANGING TUYERES AND COOLING BOXES", operable by two workers only, with a high level of security and that can be used to reduce the average time for removing tuyeres and cooling boxes from seventeen to seven hours, characterized by consisting of a set of portable, assembling devices that uses a portable hydraulic jack (33) that can be removed in several positions and directions and that are compatible for taking out the tuyere and/or the cooling box, the aforesaid hydraulic jack (33) is held in the cradle (23) and supported on the counter- cradle (25) and on the supporting bar (21 ) and, still, by a set of devices basically constituted of a longitudinal rectangular bar (13 A) and a positioning bar (16).

2. "TOOLING FOR CHANGING TUYERES AND COOLING BOXES", according to claim 1 , characterized by the fact that the longitudinal rectangular bar (13A) has a rectangular profile and it is purposed to prevent that it is moved by rolling during the operation and , still, by having the rebound (18), wheel bores (27) and the containment bolt (28).

3. "TOOLING FOR CHANGING TUYERES AND COOLING BOXES", according to claim 1 , characterized by the fact that the cradle (23) keeps the hydraulic jack (33) and by being crossed by the drawer (24) whose hole (26) will coincide with the wheel bores (27), where it will be articulated with them by the containment bolt (28).

4. "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" , according to claim 1 , characterized by using a positioning bar (16) that has a wedge (17) in its extremity.

5. "TOOLING FOR CHANGING TUYERES AND COOLING BOXES", according to claim 1 , characterized by having a vertically positioned drawer device (30) of the cooling box (7) ready to work, the wheel bores (27), the supporting bar (21) that is supported on the holder (12) with its window (22) and jack's cradle (23), counter-cradle (25) and drawer (24) as well as the longitudinal bar (13) and the containment bolt (28).

Description:

"TOOLING FOR CHANGINQ TUYERES AND COOLING BOXES".

Blast furnaces constitute the core of the steel industry. It is in them that the iron oxide ores, granulated or pre-processed to make "sinter", are subjected to the hot chemical reduction process, having the carbon as reagent, and they are turned into a metallic alloy composed of more than 97% of the iron element, called "pig iron".

The metallic iron in liquid state, with a temperature of about 1 ,500 Centigrade degrees and that flows from the blast furnaces in the runs, is taken to the other pieces of equipment of the steel plant, which will process it to turn it into steel, that is, a complex alloy of iron and other elements with the fewest contents of sulfur, phosphorus and other contaminants as possible. We say that the blast furnaces are the core of the steel industry because they provide raw material to all the subsequent processes. The modern blast furnaces are located in the center of a complex of peripheral pieces of equipment that are responsible for their high productions and quality; the regenerators increase their thermal economies allowing the air injection through their tuyeres to be done at about 1 ,200 Centigrade degrees, special lances make the coke or charcoal fines (breeze) be injected through their tuyeres in order to rise their thermal performances, they receive sinter rather than the granulated ore, besides a stoichiometric amount of water steam in such a way, due to their geometry, that they use the hydrogen formed as a reducing element.

Nowadays, supported by the technological advances in the last 50 years and by the recent automation support, the blast furnaces are considered to be near their maximum evolution limit, that is, obtaining improvements in the industrial reduction process for oxidated iron ores is only possible with radical changes of paradigm.

Due to economical matters related to the productivity and to the cost reduction, the blast furnaces must have bigger and bigger production capacities, of about millions of tons/year.

The current operational indices are around 99% of the time and the high productivities reached are also due to the millions of dollars invested in the automation and computerization of the blast furnaces.

However, when the costs of each stopped hour are observed, a huge need of innovating the processes and maintenance equipment of the pieces and of the most wasted equipment is noticed so that the stopped hours be reduced.

A blast furnace with a production of 2,800,000 tons per year produces 7,670 tons a day or 320 tons an hour.

For the current prices of US$250.00 per ton of pig iron, there is a theorical production loss of US$80,000 per stopped hour.

Taking the finished products of about US$500.00 per ton into consideration, the production loss per stopped hour is that of US$160,000.00.

One should also take into account that when a blast furnace process is interrupted, it is rather slowly than abruptly, previously decreasing the production for several hours- and similar timings are necessary for returning to the status of maximum production process.

This means a loss of basic production - despite other systemic losses - of about US$200,000.00 per stopped hour.

However, despite the great technological advances of the blast furnaces and of the peripheral pieces of equipment that support them, those simplest pieces of equipment, such as the pieces of equipment and tooling for changing tuyeres and many others, have been the same for decades.

Analyses reveal that the maintenance halts, whether programmed or not, of the simplest pieces of equipment which are auxiliaries for the blast furnace work, such as water hoses, sealing refractories of the iron notches, tuyeres and tuyere cooling boxes, etc., are responsible for great losses of their productivities.

Thus, the equipment productivity and the operational processes improvements, known as "supportive services and equipment to the blast furnace", have been the target of great managing efforts, once their importance is clear in order to reduce the number of stopped hours.

It must be stated that the maintenance services performed in the blast furnaces are carried out in extremely hard conditions, due to the high temperatures near such equipment, due to the restricted conditions of space for movement and correctly anatomic positioning, besides always demanding great physical efforts, as they deal with heavy pieces and tools that are hard to handle; in other words, such tasks take long to be carried out due to the local conditions and to comply with the work security rules. According to the current State of the Art, the two most difficult and that take the longest time to be removed and replaced are the tuyeres and their cooling boxes, for the following reasons:

1 st - They are pieces that, respectively, weigh an average of 150 and 750 kilos;

2 nd - They are very difficult pieces to be handled and they cannot get scratched or suffer any other kind of damage; 3 rd - The places where the tasks are carried out are restricted and extremely hot.

4 th - The cooling boxes are connected with the tuyeres by pressure in order to generate sealing, by a perfect overlapping; the tuyeres have a straight contact with the hottest area of the blast furnace through which the heated air enters at around 1.200 degrees Centigrade, enriched with five percent more of oxygen; it is through them that the coal fines (breezes) dragged by the nitrogen are injected. As both the tuyeres and part of their cooling boxes operate under extremely complex and aggressive chemical conditions, both accumulate fused metal and a number of other compounds on their surfaces that come to weld among themselves and with the places where they are fit in the blast furnaces and, therefore, they are extremely hard to be removed. 5 th - The average time for replacing these two pieces takes about 17 hours and the operation must be " performed when the blast furnace is stopped; taking the aforesaid values into account, one can see the value of the losses due to the current State of the Art for these two pieces replacement.

The object of this patent - "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" - constitutes the result of investments and systematic

efforts in researches and experiments in the sense of reducing the number of stopped hours for removing and replacing the tuyeres and their cooling boxes.

Advances in the State of the Art of the object of this patent. The use of the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES", object of this patent, reduces the average time spent on the replacing operation of the tuyere and its cooling box, from seventeen to seven hours, with a significant reduction of the values lost due to the production interruption as cited above and, moreover, it minimizes the workers' physical efforts with- a remarkable increase of operation security. Illustrations, description and operation of the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES", object of this patent, that consists of a set of portable and operable devices that can be assembled by two workers only under high security conditions and that applies the strength of a hydraulic jack, of around a hundred tons, in a few minutes and uses the least human effort.

For perfectly understanding the advances achieved by the object of this patent, Figure 1 illustrates the set "tuyere-cooling box" relations with the other blast furnace pieces; Figure 1A shows the details of their fitting and Figure 2 shows the conventional process of their removal by the methods that the object of this patent comes to replace.

Figure 1 is a schematic frontal cut that omits, for simplicity matters, the representation of the unnecessary pieces for the issue understanding, such as refractories, the display, etc.; in it we see the ring-like tube, the heated air dispenser (1), the straight tube (2), the dilatation joint (3), the several flanges (4) that link these pieces, the pipe bend (11), the conic tube (5), the nozzle (6), the cooling box (7), the seat (9) of the tuyere (8) and the seat (10) of cooling box (7), such conformations of these pieces that, respectively, allow the perfect adaptation and seal between the nozzle (6) of the conic tube (5) and the tuyere (8) and between this and the cooling box.

Figure 1 also shows the relations between the cooling box (7) and the tuyere (8) with the other pieces and areas of the blast furnace which are important

for understanding the object of this patent; thus, the vertical line A-B indicates the separation between the interior area of the blast furnace and the presence of a part of the cooling box (7) and of the whole tuyere (8), whose depth is indicated by the horizontal arrow A-C, being the horizontal arrow A-D the one that points out the blast furnace wall area, which includes the refractories and the blast furnace metallic furnace shell (31) on which the holder (12) is fixed, which is seen in a frontal cut and must be understood as a welded ring, or somehow fastened to the blast furnace shell (31 ) and where the pipe bend (11) and, therefore, the conic tube (5) are tightly held by tie rods, thus keeping the cooling box (7), which contains the tuyere (8), placed in their operational position.

Figure 1 illustrates the overlapping and perfect adaptation relations between the conic tube (5), through the seat (9) with the tuyere (8) and between this, through the seat (10) with the cooling box (7) and between the set with the blast furnace internal areas and the metallic furnace shell (31) and the holder (12).

Figure 2 illustrates the classic tooling and process used for removing the tuyere (8) after the conic tube (5) and the pipe bend (11) removal, which are not pointed out in this Figure 2; in it, we see, besides the metallic furnace shell (31) and the holder (12), the longitudinal bar (13) that ends at the contact spot with the tuyere (8), shaped like a rebound (18), which is kept in that position during the removal by the wedge (17), formed by the ending of the positioning bar (16) and its opposite side, that comes to form the wheel bore (14), to which hooks or steel cables are connected, pointed out by the arrow (15), which indicate the direction of the force applied to the system for removing the tuyere (8). The forces represented by the arrow (15) are usually practiced from the tackles or the pulleys system connected by any means to the wheel bore (14) and the tuyere (8) removal process takes long and it is not always possible. When it is impossible to remove the tuyere (8) by the classic process and tooling described above, a new process, which is harder and takes as much time, is used; as illustrated in Figure 3, when the tuyere (8) is so tightly

adhered to the cooling box (7) that it cannot be displaced only through the forces that are applied, represented by the arrow (15). An emptied cylinder (20) of a great weight, purposed to be used as a ram, is introduced in the longitudinal bar (13), there it is kept by the bolt (19) that goes through it by the hole (19A) and, by means of human effort that must be repeated as many times as needed, it is moved longitudinally along the longitudinal rectangular bar (13) to hit with the bolt (19) with the emptied cylinder (20), whose efforts spread over the longitudinal bar (13) and work over the rebound (18), making powerful hits on the tuyere (8) from the blast furnace interior to its exterior until the tuyere (8) is removed; in Figure 3 we can also see the positioning bar (16) ending in a wedge (17), and the wheel bore (14) as well as the holder (12) and the furnace shell (31).

Figure 4 is an exploded diagonal view of the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES", object of this patent, and it is purposed to clarify the relations between its components; you can see the rebound (18) situated in the terminal frontal portion of the longitudinal rectangular bar (13 A), whose rectangular profile aims to prevent that is displaced by rolling during the operation, the wheel bores (27), the containment bolt (28), the supporting bar (21) with window (22) that contains the cradle to keep the hydraulic jack and which will be gone through by the drawer(24) whose hole (26) will coincide with the wheel bores ((27), where it will be articulated with the same containment bolt (28). The drawer (24) has such dimensions that its cradle (23) keeps a 100 ton hydraulic jack whose cylinder acts over the jack counter-cradle (25); in the same figure we can also see the positioning bar (16) ending in a wedge (17) and , in the opposite region, the terminal (29), purposed to keep the rebound (18) in its proper place. Figure 4A illustrates the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" set up and, in it, it is evident that a 100-ton hydraulic jack kept in the cradle (23) and supported on the counter-cradle (25) and on the supporting bar (21) when activated will stretch the longitudinal rectangular bar (13 A) with the same force and that, at many times, is much higher than the forces carried out on the tuyere (8), illustrated in the previous figures, by

the pieces of equipment and the previous processes, the tuyere will be taken from its position in a few minutes.

Figure 4 and 4A also address that the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" can be disassembled and that its pieces, related to the dimensions of those with which it will relate, have compatible sizes and weights to be carried and assembled by two workers only as well as the operational simplicity of the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES". In Figure 4A we can also see the rebound (18) of the longitudinal rectangular bar (13A), the positioning bar (16), its terminal (29) and its wedge (17); the containment bolt (28), the drawer (24), the supporting bar (21) window (22), the jack's cradle (23) and counter-cradle (25) can also be seen. Figure 5 illustrates the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" set up and in the tuyere (8) removal operation and in it the blast furnace metallic shell (31), the holder (12), the cooling box (7), the longitudinal rectangular bar (13A) with its terminal in a rebound (18) positioned and kept in the correct position by the positioning bar (16), ending in a wedge (17), device that is activated by one of the two needed workers to perform the tuyere (8) removal job; the supporting bar (21), the holder (12), the hydraulic jack (33) held in the cradle (23) and its cylinder overlapped with the counter-cradle (25) and the containment bolt (28) and the drawer (24) can also be seen, and it makes the operation of the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" clear when applied to the tuyere (8) removal. Figure 6 illustrates, with an exploded diagonal view, the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" with the needed changes purposed to the cooling box (7) removal shown in the previous figures and that are the rebound (18) replacement for the whirl bar (34), with the wheel bores (27) and the cooling box (7) drawer device (30), the containment bolt (28), the longitudinal bar (13), the supporting bar (21) with the window (22), the jack's cradle (23), the drawer (24), the counter-cradle (25) and the hole (26), being blatant in this figure that for the cooling box (7) removal operation

only the terminal device of the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" is changed to adapt to its new function, almost identical to its work except for the details of the cooling box (7) drawer device (30) placement that eliminates the need of the positioning bar (16) and of the wedge (17).

The introduction of the drawer device (30) in operational position inside the cooling box (7), as it rotates around the wheel bores (27), is made by its introduction when it is found in the horizontal position and, after that, with the use of levers, it is put into a vertical position so that when it is stretched by the action of the hydraulic jack 933), it brings the cooling box along with it, as illustrated in full detail in the following figures.

Figure 6A illustrates the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" set up and the drawer device (30) positioned vertically and ready to be activated, the ring nuts/wheel bores (27), the containment bolt (28), the supporting bar (21) with its window (22) and the jack's cradle (23), counter-cradle (25) and the drawer (24) as well as the longitudinal bar (13) can be seen in it.

Figure 7 illustrates the "TOOLING FOR CHANGING TUYERES AND COOLING BOXES" set up and positioned for the cooling box (7) removal, the drawer device (30) in a vertical position overlapped with the cooling box (7) after rotating on the wheel bores (27), the containment bolt (28), the longitudinal bar (13), the furnace shell (31), the supporting bar (21) supported on the holder 912), the jack's cradle (23), the jack's counter-cradle, (25), the hydraulic jack (33) and the drawer (24).