EP0142399A1 - Cooling panels for blast furnaces - Google Patents

Abstract

The present invention relates to a cooling plate (1) consisting of a cast iron element of substantially parallelepiped shape, in which are embedded longitudinal tubes arranged parallel to each other, these tubes (3a, 3b) opening onto the same face (2b) of the plate, while the face opposite (2a) to that where the cooling tubes open is embossed. The longitudinal tubes are embedded in the plate at the places where its thickness in cross section is maximum and the bosses constituting the embossing preferably have a cylindrical shape, of longitudinal axis.

Description

The present invention relates to cooling plates for blast furnaces.

These cooling plates are elements placed against the internal face of the shielding and fulfill a dual function of cooling the refractory and shielding the passage of the heat flow towards the shielding.

The use of such cooling plates arranged between the internal wall of the shielding and the refractory lining was made necessary because of the variations in heat flows inherent in modern techniques for operating blast furnaces, these variations being able to be localized, rapid and random over time.

The cooling plates consist of cast iron elements traversed in their mass by a network of tubes in which circulates a cooling fluid which is generally water. These cooling tubes emerge on one side of the cooling plates and pass through the shield, outside of which they are connected to cooling tubes of an adjacent upper or lower plate. The tubes thus connected determine the circulation lines of the fluid rising in a substantially vertical plane along the wall of the blast furnace, these lines being connected to an external circuit for circulation and cooling of the fluid.

• - qu'elles résistent aux déformations thermomécaniques résultant des flux de chaleur élevés;
• - qu'elles assurent un bon échange thermique avec le réfractaire,ce qui implique de disposer côté face chaude des formes favorisant un accrochage efficace de ce dernier.

The cooling plates must be designed in such a way:

• - they resist thermomechanical deformations resulting from high heat fluxes;
• - that they ensure a good heat exchange with the refractory, which implies having side hot face of the forms favoring an effective attachment of the latter.

However, the cooling plates known until now did not fully satisfy these conditions and had defects which led, as a result of repeated thermal stresses, to the formation of cracks in their mass and, consequently, to a risk. leakage of the heat exchanger or heat transfer fluid inside the blast furnace, as well as mechanical stress on the cooling tubes at their exit from the cooling plates and their passage through the shielding.

To remedy these difficulties, patent FR 2 493 871 describes a cooling plate consisting of a cast iron element of substantially parallelepiped shape, in which are embedded longitudinal tubes arranged parallel to each other, these tubes opening onto a same main face, respectively at the upper and lower parts of the cooling plate, in a protective sheath, one of the original characteristics of which resides in the embossed shape of the face opposite to that where the cooling tubes open out.

The present invention relates to an improvement of this type of plate making it possible to increase operating reliability, in particular thanks to a better balance of the thermomechanical stresses generated in the mass of the cooling plate.

The present invention thus relates to a cooling plate consisting of a substantially parallelepipedal cast iron element, in which are embedded longitudinal tubes arranged in parallel to each other and opening onto the same face of the plate, the face of the plate opposite to that where the cooling tubes open being embossed, characterized in that the longitudinal tubes are embedded in the plate at the places where its thickness is maximum .

According to another characteristic, the embossing consists of rows of bosses regularly spaced transversely, the external surfaces of which are portions of cylinders whose axes are aligned longitudinally.

The axes of the longitudinal tubes coincide with the axes of the cylinders.

According to a variant, the inlets and / or the outlets of certain longitudinal tubes are offset laterally with respect to the longitudinal parts of these tubes and are preferably arranged in the vicinity of the angles of the plate.

The invention is set out below in more detail with the aid of the appended drawings given by way of examples.

• - la Fig.1 est une vue en perspective d'une plaque de refroidissement selon l'invention correspondant à une application particulière ayant trait au dernier rang d'un système de refroidissement dit par "stave-cooler";
• - la Fig.2 est une vue en coupe transversale, approximativement en son milieu de la plaque de la Fig.1;
• - la Fig.3 est une vue en élévation latérale de la plaque de la Fig.1;
• - la Fig.4 est une vue en élévation d'une plaque suivant une variante de réalisation;
• - les Fig.5 et 6 sont respectivement des vues en élévation des deux faces de la plaque de la Fig.4.

In these drawings:

• - Fig.1 is a perspective view of a cooling plate according to the invention corresponding to a particular application relating to the last row of a cooling system called "stave-cooler";
• - Fig.2 is a cross-sectional view, approximately in the middle of the plate of Fig.1;
• - Fig.3 is a side elevational view of the plate of Fig.1;
• - Fig.4 is an elevational view of a plate according to an alternative embodiment;
• - Fig.5 and 6 are respectively elevational views of the two faces of the plate of Fig.4.

In Fig.1 the cooling plate 1 is seen along its face 2a exposed towards the inside of the blast furnace and which receives the refractory lining. On its opposite face 2b open the inlets 3a and outlets 3b of longitudinal cooling tubes 3 embedded in the body of the plate 1.The ends 3a and 3b of each cooling tube open from the plate 1 at the upper and lower parts respectively, at through sleeves 4a and 4b which are embedded in the mass of cast iron of the cooling plate and also serve to fix the latter on the shielding, not shown, of the blast furnace.

The cooling plate 1 has, at its upper part, a curb 5 cooled by a transverse tube 6 arranged horizontally, the inlet end 6a close to the outlet 3b of the tube 3, is also enclosed by a sheath 7 having a end embedded in the cooling plate. The cooling plate 1 has on its face 2a a set of bosses 8a, 8b, 8c etc. identical, transversely spaced from each other and aligned longitudinally to form rows.

These separate bosses have external surfaces 9 projecting from the face 2a of the plate, in the form of cylinder portions. The transverse end faces 10 of these bosses are bevelled. The axes of the cylinder portions forming the surfaces 9 are longitudinally aligned, while the transverse faces 10 opposite two adjacent bosses form a transverse groove at V profile. As can be seen in Fig. 2, the cooling tubes 3 are embedded in the body of the cast iron plate 1 and coincide with the axes of the cylindrical surfaces 9 forming bosses, so that they are placed where the cross section thickness of the plate is maximum.

In Fig. 3, the V-profile determined by the transverse faces opposite two adjacent bosses clearly appears. In this Figure, we can also see the longitudinal path of the cooling tube 3 connecting the inlets 3a and outlets 3b. plate is in position in the blast furnace, the tubes 3 are substantially vertical, while the transverse cooling tube 6 of the coping 5 is substantially placed horizontally. The distance between the centers of the tubes shown in Fig. 1 can be varied, taking care that the axis of the tube 3 coincides with the axis of the cylindrical portion which constitutes the surface 9. The tube 3 is thus surrounded by a constant thickness of cast iron equal to radius R, in which a temperature gradient can be established which makes it possible to balance the thermomechanical stresses generated by the heat exchange between the heat flow from the interior of the blast furnace and the cooling embedded in the cooling plate.

In the variant of Figs 4 to 6, the plate shown 101 has a coping 105 arranged in its central part, in which is arranged a transverse tube 106 disposed horizontally. It has on its face 102a directed towards the inside of the blast furnace, five rows of bosses 108 delimiting, as before, portions of cylinders 109 and separated by bevelled parts 110. To these five rows of bosses correspond five longitudinal cooling tubes 103 (1), 103 (2), 103 (3), 103 (4) and 103 (5). The inlet and outlet of the central tube 103 (3) are arranged in the plane of symmetry of the plate; on the other hand the inlets and outlets of the other tubes are grouped in the vicinity of the angles and the longitudinal edges of the plate. This result is obtained, for example by bending the ends of the tubes 103 (2) and 103 (4) to bring them to the - below and above, respectively, the inlets and outlets of the extreme tubes 103 (1) and 103 (5).

This arrangement is particularly advantageous since it makes it possible to increase the cooling in the zone of the corners of the plates which is usually particularly vulnerable.

Claims (6)

1. Cooling plate (1) consisting of a cast iron element of substantially parallelepiped shape in which are embedded longitudinal tubes (3; 103) arranged parallel to each other and opening onto the same face (2b; 102b) of the plate, in a protective sheath (4a, 4b), the face (2a; 102a) of the plate opposite to that where the cooling tubes open out being embossed, characterized in that the longitudinal tubes (3; 103) are embedded in the plate in places where its thickness is maximum. 2. Plate according to claim 1, characterized in that the embossing consists of rows of bosses (8; 108) regularly spaced transversely, the bosses of a row delimiting surfaces (9; 109) projecting comprising portions of cylinders roughly aligned. 3. Plate according to claim 2, characterized in that the axes of the longitudinal tubes (3) roughly coincide with the axes of said cylinder portions. 4. Plate according to any one of the preceding claims, characterized in that the bosses (8; 108) are delimited along their transverse sides by faces (10; 110) in bevel, the faces (10; 110) in look of two adjacent bosses defining a transverse groove with a V-profile. 5. Plate according to any one of claims 1 to 4, characterized in that the inlets and outlets of certain tubes (103 (2), 103 (4)) are offset laterally relative to the longitudinal parts of these tubes. 6. Plate according to claim 5, caract- in that said inputs and outputs are grouped in an area located in the vicinity of each of the angles of the plate.

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