FR2560215A1 - IMPROVEMENT TO ENVELOPES OF COWPERS OR SIMILAR APPLIANCES - Google Patents

Abstract

THE SUBJECT OF THIS INVENTION IS AN ENVELOPE FOR A WELDED SHEET OR SIMILAR APPARATUS, INCLUDING A WALL 1 MADE IN WELDED SHEET, CHARACTERIZED IN THAT IT INCLUDES A SECOND WALL 4 IN WELDED SHEET, EXTERIOR AND PARALLEL TO THE FIRST, THESE TWO BETWEEN WALLS A SPACE 5 FILLED WITH A FILLING MATERIAL 6 INCLUDING SHOTS OF A LIGHT ALLOY, ALUMINUM OR ALUMINUM ALLOY FOR EXAMPLE, FLOODED IN A BINDER BASED ON THERMO-HARDENABLE RESIN. THEREFORE CONSIDERABLY IMPROVES THE LIFETIME OF THESE APPLIANCES AND THE DUBBING AND REINFORCING PROCESS IS RELATIVELY EASY TO IMPLEMENT.

Description

The present invention relates, in particular, to cowboys

  blast furnaces, that is to say the apparatus for invert-

  in which the heating of the air is

  sent to the blast furnace nozzles.

  Such an apparatus comprises a side wall consisting of welded sheet metal plates surmounted by a dome also made of welded sheet metal. The enclosure formed by the side wall and the dome houses a combustion chamber and

a room deruchage.

  The conditions that prevail in the cowpers and

  in particular the temperature conditions (this last one

  may exceed 1300 in certain areas).

  In fact, after a few years of operation, cracks appear, especially at the dome and the combustion chamber. Cracks develop from the inside of the wall.

  metal, mainly near weldsparal-

  same way or transversally to them.They are due

  corrosive action - nitrates produced by oxy-

  Nitrogen formed at high temperature in areas where

  the tensile stresses to the metal shell

  are important. It is therefore a phenomenon of

cracking corrosion under tension.

  Such incidents may take

  and require the complete replacement of these devices, which, on the one hand, represents a cost

  extremely high and, on the other hand,

  may result in the complete cessation of the

blast furnace they serve.

  The object of this invention is to propose an arrangement which makes it possible to remedy this drawback,

  either by realizing from the beginning a device whose enve-

  The metal envelope has a design such that stress corrosion phenomena can not jeopardize the structure of the structure, either by

  already existing device to increase its useful life.

  tion. For this purpose, the subject of the invention is an envelope

  for a cowper or the like, comprising a wall

  welded sheet metal, characterized in that it comprises a second welded sheet wall, external and parallel to the first, these two walls defining a space filled 3 'a filling material comprising the shot

  of a metal or a light alloy, for example alumina

  nium or an aluminum alloy, embedded in a binder based

of thermosetting resin.

  The subject of the invention is also a method for manufacturing such an envelope, characterized in that a sheet internal wall is doubled by a second outer wall made of sheet metal, parallel to the first and delimiting

  with it a space, and one fills this space with a

  filler material comprising shot of a metal

  or a light alloy embedded in a binder based on

heat-curable sine.

  According to other features: the metal particles have dimensions of between about 0.2 and 2 mm and preferably between -0.5 and 1.5 mm; - we use aluminum or an alloy

based on aluminum.

  The invention will be described in more detail in

  referring to the attached drawing given only as an example

and on which:

  - Fig.1 is a sectional view of the envelope

  eg a cowper, made according to the invention; - Fig.2 is also a sectional view showing an embodiment in the case of thicknesses

variables of the walls.

  We see in Fig.1 a part of an envelope

  a cowper or the like comprising an integral wall

  metal frame 1 made of welded sheet whose thick

  it can be included, for example between 15 and 30 mm.

  On the face of this wall directed towards the interior of the ap-

  such is a refractory lining 2.

  On the outer face of this sheet are

  puyées sheet metal strips 3 arranged horizontally and vertically and which are welded to a second series of

  sheets forming an outer wall 4.

  Between the two walls and the spacers 3 are delimited cells 5 filled with a material of

filling 6.

  The outer wall is preferably made

  in the same grade of steel as the inner wall and

  feels a comparable thickness.

  In this respect, in the embodiment of FIG. 2, an area of the envelope in which the inner and outer walls have thicknesses is seen.

  The inner wall includes, for example, a

  lower tie 1a having a thickness of 24 mm and a b

  upper part 1 having a thickness of 17mm. The thick-

  outer wall 4a, 4b can vary in consequence.

  this, as shown in the drawing. Similarly, the thickness of

  the interval 5a, 5b delimited between the two walls may vary

  between 3 and 30 mm, a thickness of the order

  10mm is however preferred.

  The filling material of the interval-

  delimited between the walls is, according to the invention, constituted

  by aluminum shot or an aluminum alloy

  whose particles preferably have dimensions between 0.2 and 2 mm, for example, a dimension of

  the order of 0.5 or 1.5 mm being particularly favorable.

  In fact, the average size of metal granules is

  chosen so as to obtain optimal filling of the cells

  and is, in any case, less than the width

  minimum of the interval between the two.

  With regard to the composition of this

  metal mesh, use aluminum or preferably

  an alloy made of aluminum or another metal

  or light alloy with high thermal conductivity.

  The interstices between the metal granules are filled with a binder based on a resin or a thermo-hardening resin mixture resistant to a temperature

  equal to or greater than 1100C.This resin may for example be

  a phenolic polyurethane resin in powder or

  liquid gel containing the adjuvants necessary for its hardening and possibly a charge, as is conventional in molding or casting techniques.

such resins.

  According to one embodiment, the filling of the cells can be carried out as follows:

  first of all, in a mixer, a coating of the particles

  metal particles, using the powdered resin or

in the form of liquid gel.

  Then, the mixture thus prepared is prepared by injection or by pouring, optionally under a neutral gas such as nitrogen, through orifices 7 into which are introduced for example by screwing, tubings such as 8. vent holes are provided, if necessary in

  this same wall 4.The placing of the mixture may be

  do it cold. During this filling operation or immediately afterwards, a vibration operation is performed

  in order to obtain an excellent filling of the cells.

  This operation can be performed by means of a vibrator

unidirectional high frequency.

  The curing of the resin is carried out between 20 minutes and about one hour after the introduction of the mixture, this duration of course depending on the proportions

  hardener contained in the mixture.

  This hardening can possibly be

  accelerated by a slight increase in temperature.

  The orifices such as 7 are then closed, for example by means of screwed or welded plugs, so as to restore the continuity of the outer wall 4. This type of filling is particularly interesting.In fact:

  - its good thermal conductivity makes it possible to

  ter the formation of a high temperature gradient between

  both sides and therefore to limit the constraints

  dice to differential dilatation;

  the cells between the walls being entirely

  in particular because of the presence of a

  resin that fills the interstices between the metal granules

  However, the pressure between the walls and the passage of any aggressive gaseous or liquid agent coming from the enclosure of the cowper to the new envelope is prevented; - The filling product used is not attacked by nitrates so that the outer wall is isolated from them, even after cracking of the inner wall; - The mixture introduced between the walls has a low density, for example between 1 and 1.5, which limits the loads and tensile forces exerted on

  sheet metal, does not require an increase in the thickness

  walls to withstand the pressures and tempera-

  ture prevailing in the enclosure of the cowper;

  - the setting up process is particularly

  simple since it is not necessary to heat

  walls or if such heating is achieved, it is not

  only at a relatively low temperature of

  dozens of C's above zero.

  Alternatively, the spacers 3 can be sup-

  However, the process is carried out under the same conditions

Claims (7)

- CLAIMS -   1 - Envelope for cowper or similar apparatus   comprising a wall (1) made of welded sheet metal, characterized   in that it comprises a second wall (4) welded sheet, external and parallel to the first, these two walls defining a space (5) filled with a material of   filling (6) based on shot of a metal or an aluminum   light bonding, embedded in a binder based on curable.   2 - Envelope according to claim 1,   characterized in that the filler material mainly comprises aluminum shot or an alloy based on aluminum.   3 - Envelope according to any one of   1 and 2, characterized in that the particles   the metals have dimensions between 0.2 and   Approximately 2mm and preferably between 0.5 and 1.5mm.   4 - Envelope according to claim 1,   characterized in that the outer wall (4) is supported on the first wall via a network of spacers   metal t3), these two walls defining a space (5).   - Method of manufacturing an envelope   according to any one of claims 1 to 4,   characterized in that a sheet metal inner wall (1) is doubled by a second sheet metal outer wall (4) parallel to   the first, this second wall delimiting with the first   first wall a space (5), and one fills this space with   a filling material (6) comprising grenaille-   a metal or a light alloy and a binder based on thermosetting resin.   6 - Process according to claim 5, characterized   terized in that the metal shot is premixed   and the resin-based binder.   7 - Process according to any one of the   Claims 5 and 6, characterized in that the filling material is set up at room temperature   or at a slightly higher temperature. 2560215 '   8 - Process according to any one of the claims   5 to 7, characterized in that, after the filling of the cells, an operation of vibration of the envelope is carried out. 9 - Cowper or similar apparatus, comprising a   envelope according to any one of the claims 1 to 3.