Metallurgical apparatus – Means for treating ores or for extracting metals – By means applying heat to work – e.g. – furnace
Reexamination Certificate
1998-12-21
2001-07-10
Kastler, Scott (Department: 1742)
Metallurgical apparatus
Means for treating ores or for extracting metals
By means applying heat to work, e.g., furnace
C266S190000
Reexamination Certificate
active
06258315
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structural member of a furnace body having a cooling mechanism which is used for constructing a furnace wall or a bottom of a furnace of a metallurgical shaft furnace.
2. Description of the Related Arts
With respect to a metallurgical shaft furnace such as a blast furnace, it is necessary to cool the refractories of the furnace wall and the bottom of the furnace to reduce erosion from the inside of the furnace, and to prolong the service life of the furnace body. Heretofore, a variety of apparatuses have been proposed in order to cool a furnace body of a blast furnace and the like, and have been put into practical use. A stave cooler has superior properties in uniformly cooling the refractories in the furnace, so that this is universally used for blast furnaces. In general, the stave cooler has a configuration in which refractories (refractory bricks) are fixed on an inner side of a furnace of a cast metal portion, in which are cast cooling tubes.
With respect to the stave cooler, it is important that refractories (refractory bricks) be uniformly cooled and also not fall off from the cast metal portion. In order to obtain the above-mentioned properties, a cooling apparatus for a furnace body is disclosed in Japanese Unexamined Patent Publication No. 7-90334, in which a cast metal portion in which are cast cooling tubes and inner furnace refractories arranged so as to be intercalated by a heat insulating buffer member, and the inner furnace refractories are supported by inserting a supporting member for connecting into a hole for mounting provided at the inner furnace refractories, the supporting member for connecting being made of refractories protrudingly provided at a cast metal portion. In this disclosure, the supporting member for connecting the inner furnace refractories is constructed by refractories having high thermal conductivity and strength at a high temperature whose main component is molybdenum or molybdenum/zirconia or the like. Heat exchange is performed between the cooling tubes at the cast metal portion and the inner furnace refractories through the supporting member for connecting, so that the inner furnace refractories are satisfactorily cooled.
It is, however, clear that a conventional structural member of a furnace body has a problem in which inner furnace refractories easily fall off, although an object of the conventional art is proper cooling and preventing the inner furnace refractories from falling off.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a structural member of a furnace body which properly cools inner furnace refractories and also effectively prevents them from falling off.
The Inventors have studied the causes of falling off of inner furnace refractories and countermeasures therefor with respect to the above-described conventional cooling apparatus for a furnace body (a structural member of a furnace body). As a result, in the conventional cooling. apparatus for the furnace body, a supporting member for connecting is particularly constructed for refractories having high thermal conductivity and being made of molybdenum or the like as a main component, and the inner furnace refractories are cooled from the inside due to cooling properties based on high thermal conductivity of the supporting member for connecting. However, it is clear that this supporting construction of the inner furnace refractories itself is a main factor causing the inner furnace refractories to fall off.
Basic problems in the conventional construction are as follows. The supporting member for connecting made of refractories in which a main component is molybdenum or the like has low bending strength, resulting in easy breakage due to an impact load or the like. Furthermore, thermal inhomogeneities occur within the refractories due to cooling of the inside of the refractories with the supporting member for connecting so as to readily cause damage such as cracking of the refractories. It is clear that the breakage of the supporting member for connecting and the damage to the inner furnace refractories due to cooling by the supporting member for connecting are main causes of falling off of the inner furnace refractories.
Therefore, it is clear that the inner furnace refractories can be effectively prevented from falling off, because a material of the supporting member for connecting, which cannot breakdown is employed, and at the inside of the inner furnace refractories, it is possible to maximally avoid cooling by the supporting member for connecting in contrast to the conventional art, so as to prevent the inside of the refractories from producing thermal inhomogeneities. On the other hand, it is also clear that the inner furnace refractories are properly cooled only by a rear surface which is brought into contact with a stave side, although the inside of the inner furnace refractories are cooled by the supporting member for connecting.
The present invention is performed based on the above-described knowledge, and the features are described below.
[1] A structural member of a furnace body for a metallurgical shaft furnace, including: a metallic structural member having a flow path for a coolant therein; inner furnace refractories provided on a cooling surface of the metallic structural member; metallic supporting members for connecting which support the inner furnace refractories on the metallic structural member by being protrudingly provided on the cooling surface of the metallic structural member and by being inserted into grooves for mounting or holes for mounting formed on a rear surface side of the inner furnace refractories; and heat insulating members being inserted between the supporting members for connecting and inner surfaces of the grooves for mounting or the holes for mounting.
[2] A structural member of a furnace body for a metallurgical shaft furnace described in the paragraph [1], wherein the metallic structural member comprises a cooling tube which forms the flow path for the coolant and a cast metal portion which is cast around the cooling tube.
[3] A structural member of a furnace body for a metallurgical shaft furnace described in the paragraph [1] or [2] further comprising a heat insulating buffer member arranged between the cooling surface of the metallic structural member and the rear surface of the inner furnace refractories.
[4] A structural member of a furnace body for a metallurgical shaft furnace described in any of the paragraphs [1] to [3] further comprising, a plurality of refractory bricks as the inner furnace refractories; and grooves for mounting formed at both side portions of a rear surface side of each refractory brick for inserting the supporting members for connecting.
[5] A structural member of a furnace body for a metallurgical shaft furnace described in the paragraph [4], wherein a length a of the groove for mounting in the width direction of the refractory brick and a distance L between the groove for mounting and an upper end surface of the refractory brick satisfy the relationships L>a.
[6] A structural member of a furnace body for a metallurgical shaft furnace described in any of the paragraphs [1] to [5], wherein the supporting member for connecting includes a metallic cylindrical bar.
[7] A structural member of a furnace body for a metallurgical shaft furnace described in any of the paragraphs [1] to [6] further comprising, a plurality of rear bricks provided protrudingly on the rear surface of the inner furnace refractories, and the cooling surface of the metallic structural member being formed along the rear surface of the inner furnace refractories including an outer surface of the rear brick.
[8] A structural member of a furnace body for a metallurgical shaft furnace described in any of the paragraphs [4] to &l
Araki Tsuneo
Fukagawa Kenichi
Sakai Atsushi
Sumigama Takashi
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Kastler Scott
NKK Corporation
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