Patent Publication Number: US-6660222-B1

Title: Cooling plate for a shaft furnace

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to cooling plates (so-called staves) for shaft furnaces, in particular, blast furnaces, provided with a refractory lining, comprising cooling channels loadable with a cooling medium, wherein at least the front side facing the interior of the furnace is comprised of an ingot, produced preferably of copper or a low-alloy copper alloy and provided with grooves for receiving refractory material. 
     2. Description of the Related Art 
     It is known to provide such cooling plates with a water cooling system and to produce them of copper or a low-alloy copper alloy in order to provide a minimal resistance to the heat to be dissipated. 
     In the prior German patent 29 07 511 the cooling channels are provided in a forged or rolled ingot as vertically extending blind bores which are introduced by mechanical gun drilling. Such cooling plates must have a relatively great thickness in order for the cooling channels to have still a sufficient wall thickness to withstand the operating pressure of the cooling medium. Copper plates of the thickness required for this are expensive as a result of the high copper prices. The blind bores have for a circular cross-section only the smallest possible inner surface area. Accordingly, for heat exchange with the cooling medium only little surface area is available, and only a moderate heat dissipation is achieved. This results in high thermal stress of the cooling plate, and this negatively affects its service life. 
     SUMMARY OF THE INVENTION 
     The invention has the object to configure cooling plates of the aforementioned kind such that they can be produced with a reduced material expenditure and a reduced manufacturing expenditure and can be mounted more easily in comparison to those known in the art and that with them higher cooling capacities with reduced cooling medium throughput can be realized wherein the own heat uptake is limited such that a significantly longer service life can be obtained. 
     As a solution to this object it is provided to produce the front part of the cooling plate trough-shaped in the central area as a domed rolled part of relatively minimal thickness so that a considerable amount of copper material can be saved and to supplement the domed area by a second, also outwardly domed rolled part to a cooling channel with a cross-section deviating from a circular shape and to thus provide a higher cooling output. In addition to the advantage of a reduced copper consumption, this provides the benefit of a more intensive cooling action which, as desired, increases the service life. 
     Advantageous and expedient further developments of the subject matter of the invention are characterized in the dependant claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained with the aid of the description of one embodiment in connection with the drawings illustrating it. It is shown in: 
     FIG. 1 a central cross-section of the cooling plate; 
     FIG. 2 a cross-section of the cooling plate extending through the area of the pipe connecting pieces; 
     FIG. 3 a twice interrupted longitudinal section of a cooling plate mounted on a shaft furnace wall; and 
     FIG. 4 a view of the cooling plate from the rear. 
    
    
     In FIG. 1 a cross-section of the cooling plate, positioned at the center of its length, is illustrated which shows a shield  1  which faces the interior of the furnace and is rolled of copper or a copper alloy to be through-shaped. Transversely extending grooves  4  have been rolled into its free surface which, at the end of the assembly, facilitate the application of refractory ramming or spraying material which are beneficial for the later adhesion of the burden. In order to provide an efficient cooling channel  2 , a supplemental section  3  is connected by welding seams  13  to the shield  1 . This supplemental section is also rolled to be trough-shaped; however, across substantial portions of its length it also has a stay  5 , which extends perpendicularly from its center which and increases, on the one hand, the stability of the entire cooling plate and, on the other hand, facilitates its assembly. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For assembly, a holder  8  is fastened to the inner wall  9  of the shaft furnace, in the embodiment by welding, which holder is provided with bores  6 . For effecting the assembly, it is sufficient to introduce the stay  5  into the holder  8  and to introduce a bore  6 ′ into the stay  5  from the side which bore is aligned with the bore  6  in the holder  8 . The actual connection is then realized by inserting and securing the bolt  7  in the bores  6 ,  6 ′. Subsequently, the cooling plate can be back-filled with a back-filling material  10  and subsequently, not illustrated in FIG. 1, the surface of the shield  1  of the cooling plate can be covered with a refractory ramming or spraying material. 
     FIG. 2 shows also a cross-section of a cooling plate but in its end area. The shield  1  as well as the supplemental section  3  are illustrated which are fixedly and tightly connected by welding seams  13 . Into a bore provided in the supplemental section  3  one end of a pipe connector piece  12  is inserted and connected with the supplemental section fixedly and tightly by a welding seam  14 . A corresponding longitudinal section which shows, in particular, both ends with caps  11  and pipe connector pieces  12  is shown in FIG.  3 . 
     In practice, the cooling plate is not used individually; it is provided as a module which is combined to larger cooling surfaces. Mounting of the cooling elements is carried out such that the front parts of the cooling plate, positioned laterally to the cooling channel and representing only one element of the cooling surface, overlap with corresponding parts of the neighboring cooling plate. In this way, in conical sections of a blast furnace armor, for example, the belly of the shaft furnace, the shaft or the like, it is possible to provide a compensation of different diameters or peripheries of the armor without the width dimensions of the cooling plate having to be adjusted to the cone shape. 
     The welding of the shield  1  with the supplemental section  3  to form the cooling plate or the modular cooling element is carried out preferably continuously by means of a corresponding welding robot so that a uniform, flawless, and liquid-tight configuration of the welding seam is ensured. While for reasons of thermal conduction the shield  1  is manufactured of copper or a copper-rich alloy, the supplemental section  3  can be produced of less expensive materials which possibly have the advantage of higher strength. It is only important that the shield  1  and the supplemental section  3  can be welded well and easily. 
     List of Reference Numerals 
       1  shield 
       2  cooling channel 
       3  supplemental section 
       4  groove 
       5  stay 
       6  bore 
       7  bolt 
       8  holder 
       9  inner wall 
       10  back-filling material 
       11  cap 
       12  pipe connector piece 
       13  welding seam 
       14  welding seam