EP0349513A1 - Thermic shield permitting renovation of Cowpers and process for its putting into practice - Google Patents

Abstract

A thermic shield essentially comprising a cushion (11) formed by two linings of composite materials capable of resisting temperatures of the order of 800 to 900 DEG C, and capable of being inflated by means of a turbine. The cushion is provided with an inlet sleeve (13) connected to a turbine and at least one evacuation sleeve (15), in a manner such as to sustain the circulation of renewable air in the cushion. The cushion rests on an appropriate supporting element (3,4,5). The device is intended to constitute a thermic shield designed to be installed in the shaft of a Cowper or other shafts with a view to permitting renovation or repair work to the latter without cooling the cupola of the Cowper. <IMAGE>

Description

Subject of the invention

The present invention relates to a thermal insulation shield intended to allow, under acceptable conditions and with good security, repair operations in all applications where thermal insulation and mechanical protection are required, and in the particular case of cowpers. used in steel plants. It also relates to the process by which such a heat shield can be implemented.

Scope and summary of the prior art

Cowpers are intended to produce the hot wind necessary for blast furnaces. They produce hot winds that can reach temperatures of around 1260 ° C at their exit from the cowper and the dome lined with refractory silica bricks can reach temperatures of around 1400 ° C. The cowper is an inversion device comprising a beehive of refractory materials and it comprises a generally elliptical section well or chimney extending practically from its base to the dome, that is to say over several tens of meters.

A ceramic or other refractory burner is disposed at the bottom of said well or in other cases.

Due to the very nature of the lining, in particular that of the dome, it is not possible to carry out repairs by accessing the well without having allowed the cowper to cool. Repair operations must necessarily be done without a substantial reduction in the dome temperature.

No satisfactory solution has so far been proposed for repairing or rehabilitating a cowper which has suffered damage, either at the base of the beehive or at the refractory burner.

Aims of the invention

The main object of the invention is to provide means for working in satisfactory conditions inside a cowper without having to substantially lower the temperature of the dome.

In addition, the invention aims to provide means allowing said work by protecting workers from falling splinters, rubble, carbuncles or slag resulting for example from local cooling or other causes.

The installation of the heat shield must be able to be ensured by using the possibilities of existing accesses without excessive demolitions.

Simple means must be used which allow rapid implementation to avoid having to interrupt the use of the cowper for too long.

The workers brought into the cowper with special equipment must find a thermally bearable atmosphere there.

Other characteristics and advantages of the technique proposed by the invention will appear on reading the description.

Character-defining elements of the invention

According to the invention, a heat shield is proposed which essentially consists of a cushion formed by two envelopes of composite materials capable of withstanding at least during the time of the work at temperatures of the order of 800 to 900 ° C., which can be inflated to using a blowing turbine and which is provided with at least one intake sleeve connected to the blowing turbine and at least one exhaust so as to maintain a continuously renewable air circulation, said cushion resting on a suitable heeling element.

According to the invention, the cushion can be folded up by rolling it and can be deployed by unwinding on the bed as it is inflated by the blowing turbine.

The cushion can therefore be introduced by placing it on the bed in the rolled up state and deploying under the action of the blower.

The heeling must itself be designed to adapt to the dimensions of the free section of the well and be able to be installed so as to pass through a reduced-size access that constitutes the sleeve of the hot wind valve arranged according to an axis approximately transverse to the well.

According to the invention, the housing is advantageously constituted by tubular elements, preferably made of stainless steel. The heeling advantageously consists of two essentially symmetrical side parts and a central part slid over or nestable in the two side parts, the assembled assembly affecting the elliptical shape of the section of the well.

Advantageously, at least the two lateral parts each consist of two lateral half-parts which can be folded by a hinge element, one on the other, and which can be described by deploying on the hinge an angle of 180 ° up to a stop. We can therefore introduce each side part in the vertical position in the folded state and ensure its deployment by rotation to the horizontal by ensuring the opening of the two side half-parts.

A trellis can be mounted so as to retain a refractory wool between the tubular reinforcing parts of the elements constituting the bedding and external layers of refractory wool can be laid on the bedding before bringing the cushion there.

The implementation of the material described is carried out by accessing the cuff of the hot-air valve and by resting on the flange of this cuff after dismantling the compensator to mount two gantry cranes there, the two lateral parts of the heel being first introduced in place by bringing them vertically to the folded state and then tilting them while deploying the two parts of which they are made; then the central part is slid between the two lateral parts, thus covering the entire section of the well. After possible interposition of an additional layer of refractory insulation, the cushion is deposited on the central part of the bed and is deployed under the action of the blowing turbine.

Brief description of the drawings

In order to better understand the invention, reference will be made to the appended figures which schematically represent the principles of construction and implementation of the heat shield.

• - la figure 1 représente en plan la mise en place d'une première partie latérale du gîtage;
• - la figure 2 représente en plan la mise en place d'une deuxième partie latérale du gîtage, la pre­mière partie latérale déjà en place n'étant pas représentée;
• - la figure 3 représente en plan la mise en place de la partie centrale du gîtage, les deux parties latérales déjà en place n'étant pas repré­sentées;
• - la figure 4 représente en plan le coussin tel qu'il est déposé sur le gîtage;
• - la figure 5 est une vue en coupe longitudinale selon V - V de la figure 4;
• - la figure 6 est une vue en coupe transversale selon VI - VI de la figure 4;
• - la figure 7 est une vue de détail de profil illustrant la mise en place d'un premier portique dans la manchette de la vanne à vent chaud, vue correspondant à la coupe VI - VI de la fi­gure 4;
• - la figure 8 est une vue de face correspondant à la fi­gure 7 de la manchette de la vanne à vent chaud et d'un portique qui y est monté;
• - la figure 9 représente la pose d'un bras télescopique dans la partie supérieure du portique qui est représenté partiellement;
• - la figure 10 représente l'emboîtement d'une partie laté­rale (gauche) de gîtage sur le bras télesco­pique;
• - la figure 11 représente le déploiement de la partie laté­rale dans une vue correspondant à la figure 8;
• - la figure 12 représente le déploiement dans une vue cor­respondant à celle de la figure 10;
• - la figure 13 représente le relèvement d'une partie laté­rale (droite);
• - les figures 14 et 15 représentent un détail de la façon dont est introduit le coussin gonflable, respectivement en une vue de face et une vue de profil et
• - la figure 16 représente le coussin en cours de gonflage et de déroulement.

In the drawings, identical references are used for identical or similar parts in the different views:

• - Figure 1 shows in plan the establishment of a first lateral part of the housing;
• - Figure 2 shows in plan the establishment of a second side portion of the housing, the first side portion already in place is not shown;
• - Figure 3 shows in plan the establishment of the central part of the housing, the two side parts already in place are not shown;
• - Figure 4 shows in plan the cushion as it is deposited on the bed;
• - Figure 5 is a longitudinal sectional view along V - V of Figure 4;
• - Figure 6 is a cross-sectional view along VI - VI of Figure 4;
• - Figure 7 is a detail view in profile illustrating the establishment of a first gantry in the cuff of the hot air valve, view corresponding to section VI - VI of Figure 4;
• - Figure 8 is a front view corresponding to Figure 7 of the cuff of the hot air valve and a gantry which is mounted therein;
• - Figure 9 shows the installation of a telescopic arm in the upper part of the gantry which is shown partially;
• - Figure 10 shows the interlocking of a lateral (left) part of heeling on the telescopic arm;
• - Figure 11 shows the deployment of the side part in a view corresponding to Figure 8;
• - Figure 12 shows the deployment in a view corresponding to that of Figure 10;
• - Figure 13 shows the raising of a side part (right);
• FIGS. 14 and 15 show a detail of how the airbag is introduced, respectively in a front view and a side view, and
• - Figure 16 shows the cushion during inflation and unwinding.

Description of a preferred embodiment of the invention

Referring to Figures 1 to 3, we can see the way in which the heel elements are installed. The general shape of the deposit corresponds to the section of the well and affects that of an ellipse; the heeling is indicated by the general reference 1.

The hot-air valve sleeve has the mark 2.

The housing consists of two lateral parts, respectively a left part 3 (Figure 1) and a right part 4 (Figure 2) and by a central part 5 (Figure 3).

The side part 3 is made of elements tubular, preferably made of stainless steel which constitute a frame and consists of two parts 3a and 3b which can pivot on a hinge 9, one relative to the other as indicated by arrow 7.

The constituent elements 3, 4 and 5 of the bed are of an adequate shape to cover the ellipsoidal section of the well and their placement will be described in more detail below.

The elements are formed so as to be light and are formed of a frame as shown, preferably lined with insulating and refractory materials, held for example by a wire mesh.

On this bed 3, 4 and 5 is deployed an airbag 11 shown in Figures 4, 5 and 6. It is a double envelope of refractory fabrics whose interior space is in communication with at least one cuff supply of blown air by a blowing turbine and with at least one evacuation sleeve, it being understood that the respective sections of the intake and evacuation sleeves are such that the cushion inflates under the air pressure creating a pressure in the envelopes but allowing adequate air circulation inside it. Tensioners 17 arranged inside the envelopes ensure an arrangement in a suitable shape of the cushion and avoid bursting in the event of overpressure.

The mounting of the different elements will be more apparent by referring to Figures 7 to 12.

In Figures 7 and 8, there is shown the mounting of a first gantry in the form of a bracket 20 on the flange of the cuff 2. The gantry 20 (left in this case - see Figure 8) is fixed on a spacer 21 bolted to this flange.

It receives (Figure 9) a telescopic arm 23 which can exceed the cuff 2 overhanging in the well of the cowper and is fitted there (Figure 10) the left side part of the housing in the folded state.

Thanks to the telescopic arm, it is possible to advance the element 3 in complete overhang over the cowper well which allows deployment by the hinge 9 to affect the position shown in Figure 12. The movement is controlled by a lever 31 mounted on the end 33 of the telescopic part 23 equipping the gantry. Plates 35 (Figure 11) welded at an angle block the hinge beyond a movement of 180 °. It therefore becomes possible after deployment to raise the element 3 using the lever so that it occupies its final location where it will be blocked by any appropriate means.

The installation of the heeling element 4 is carried out in the same way using a gantry element arranged symmetrically to the first.

FIG. 13 shows this operation for the right lateral part 4 of the housing from a position shown in center lines to a position shown in solid lines. The movement is ensured by the lever 31 from its position in center lines to its position in solid lines. The plates 35 prevent rotation beyond 180 ° on the hinge connecting the parts 4a and 4b.

FIGS. 14 and 15 show how the cushion is arranged in the folded state and brought to an articulated support 40 to be placed on the central part 5 of the housing and to deploy on the lateral parts 3 and 4.

The central heeling element can be simply deposited (as shown in Figure 5) on the side parts 3 and 4 or nest thereon.

It is understood that the heat shield as it is mounted effectively isolates the upper part of the cowper well from the lower part. The workers who will be required to operate in this lower part, under the protection of the heat shield, are thermally insulated and protected against accidental falls of the lining parts which may fall in particular from the dome.

In addition, a relatively well thermally protected space is created in the lower part of the well. In this room, it is possible to provide air circulation to maintain a temperature bearable. Of course, if necessary, both thermal protection elements against additional falls can be provided in the chamber thus created.

In this way it becomes possible to carry out repair or repair work, which until now has not been possible.

Claims (8)

1. Heat shield characterized in that it consists essentially of a cushion (11) formed by two envelopes of composite materials capable of withstanding temperatures of the order of 800 to 900 ° C, which can be inflated using a blower turbine and which is provided with at least one intake sleeve (13) connected to the blower turbine and at least one discharge sleeve (15) so as to maintain a circulation of renewable air in continuous, said cushion (11) resting on a suitable heeling element (3, 4, 5). 2. Shield according to claim 1 characterized in that the cushion (11) is folded by rolling it and can be deployed by unwinding on the bed (3, 4, 5) as it is inflated by the blowing turbine. 3. Shield according to claim 1 or 2 characterized in that the housing (3, 4, 5) is designed so as to adapt to the dimensions of the free section of the well and can be set up so as to pass through a access of reduced dimensions constituted by the sleeve (2) of the hot wind valve. 4. Shield according to claim 3 characterized in that the housing consists of tubular elements, preferably made of stainless steel. 5. Shield according to claim 3 or 4 characterized in that the housing consists of two side parts (3, 4) essentially symmetrical and by a central part (5) slid over the two side parts (3, 4) or nestable on these, the assembled assembly affecting the elliptical shape of the section of the well. 6. Shield according to claim 5 characterized in that the two lateral parts (3, 4) are each constituted by two lateral half-parts (respectively 3a, 3b and 4a, 4b) foldable by a hinge element (9), one on the other, and being able to describe by deploying on the hinge (9) an angle of 180 ° up to a stop (35). 7. Shield according to any one of Claims 1 to 6 characterized in that a trellis is mounted so as to retain a refractory wool between tubular reinforcing parts of the elements constituting the bedding (3, 4, 5), external layers of refractory wool may possibly be laid on the housing (3, 4, 5) before bringing the cushion (11) there. 8. Method for the implementation of a shield according to any one of claims 1 to 7 characterized in that access to the cuff (2) of the hot wind valve and that one is supported on the flange thereof, after dismantling the compensator, to mount two gantries (20) there, the two lateral parts of the housing (3, 4) being first introduced in place successively by bringing them vertically to the folded state and then tilting them while deploying the two half-parts (respectively 3a, 3b and 4a, 4b) of which they are made; then, the central part (5) is slid between the two lateral parts (3, 4) thereby covering the entire section of the well; after optional interposition of an additional layer of refractory material insulation, the cushion (11) is finally deposited on the central part (5) of the housing, in the rolled up state and its deployment is carried out under the action of a blower or other source of compressed air.

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