US2319571A - Cooling plate for blast furnace inwalls and mantles - Google Patents

Description

y 1943 J. L. wlcK, JR, ETAL 2,319,571

AST FURNACE INWALLS AND MANTLES 2 Sheets-Sheet l COOLING PLATE FOR BL Filed Oct. 29, 1941 INVENTORS.

wzcx J2 JHMES L. 7 W5 M. NESSELBUSH BY fbeir A770 7 y 1943 J. WICK, JR., ETAL 2,319,571

COOLING PLATE FOR BLAST FURNACE INWALLS AND MANTLES Filed Oct. 29, 1941 2 Sheets-$heet 2 i 19 \Q I true when the furnace Patented May 18, 1943 COOLING PLATE FOR BLAST FURNACE INWALLS AND MANTLES James L. Wick, Jr.,

Youngstown, Ohio, Bromte Company,

and Louis .M. Nesselbush,

assignors to The Falcon Youngstown, Ohio Application October 29, 1941, Serial No. 416,968

2 Claims.

This invention relates to metallurgical blast furnaces, and more particularly to those portions thereof which comprise the mantle and the inwall which rests on the mantle and extends thereabove to form the upper portion of the shaft or stack.

In the operation of a metallurgical blast furnace it is extremely difflcult to satisfactorily cool the upper portion thereof, and this is especially M is operated over a protracted period of time. For reasons which will appear more fully hereinafter, the inwall which rests on the mantle and extends thereabove are so constructed and arranged that they do not readily lend themselves to alteration the mantle and in the manner of the other portions of the furnace.

It is among the objects of the present invention to provide for more efilcient cooling of blast furnace inwalls and mantles.

Another object is the provision of a cooling plate for the inwalls and mantles of metallurgical blast furnaces which, while not removable, is so constructed and arranged as will not only permit of replacement of the means for supplying the cooling water thereto, but one which is at the same time extremely durable in use.

The invention, then, comprises the features hereinafter more fully described and as particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail a certain illustrative embodiment of the invention, this being indicative of but one of a number of ways in which the principles of the invention may be employed.

In said drawings:

Figure l is a fragmentary sectional elevation of a metallurgical blast furnace embodying in the inwall and mantle portions thereof the coolin plate of the present invention, the said plate being shown in and elevation and as employed in large number.

Figure 2 is an enlarged fragmentary horizontal sectional view through a portion of either the mantle or inwall of the metallurgical blast furnace of Figure l, the cooling plates therefor being shown in plan.

Figure 3 is an enlarged fragmentary horizontal sectional view of a portion of the mantle or inwall of Figure 2, and illustrates one of the cooling plates and the protection pipes for the water conduits in section, the said water conduits being fragmentarily shown in plan.

Figure 4 is a sectional view on the line IV-IV of Fig. 3.

Referring more particularly to the drawings, the numeral l designates the hearth, or crucible, of a metallurgical blast furnace, the same comprising the lowermost portion thereof and serving as a receptacle for the molten metal and slag. This portion of the furnace is composed of refractory brickwork and the side walls thereof are usually enclosed by a jacket of heavy metal plates which. is cooled by a suitable water-circulating system. Disposed immediately above the hearth orcrucible l is the bosh section 2 of the furnace, and this too is composed of refractory brickwork. Ordinarily, however, the refractory brickwork of the bosh section is not enclosed by a jacket of heavy metal plates in walls of the hearth or crucible; but in any event it is provided with a multiplicity of recesses which extend from the exterior for a substantial distance into the brickwork. The outer ends of these recesses are open, whereby they may receive hollow water-cooled bosh plates which can be readily replaced in case of failure in service. conventionally these hollow water-cooled bosh plates take the form of relatively fiat bodies of greater length than width, the interiors providing passageways for permitting the inward and outward passage of cooling water therethrough in directions radially of the axis of the shaft of the furnace.

Immediately above the bosh section of the furnace is the mantle, which is concentric with the bosh and the hearth or crucible, and is supported by a series of pillars which rest on foundations supported by the main furnace foundations. Resting upon the mantle and extending thereabove is the inwall, or upper portion of the shaft or stack of the furnace. Th walls of the mantle and inwall resting thereon, which are hereinafter designated at 3 and 4 respectively, are composed of refractory brickwork and are usually materially thicker than the walls of either the bosh section 2 or the hearth or crucible l. According to conventional design, there is buried within the refractory brickwork of the inwall and the mantle at the time of their erection a multiplicity of hollow water-cooled plates, which are provided with water intake and outlet conduits which extend to the peripheries thereof. The refractory brickwork of the walls of the mantle and the inthe manner of the side of those portions of the wall of the furnace in which they are buried. Like bosh plates, they are relatively flat hollow bodies which are provided with interior passageways for permitting the circulation of'cooling water, but these passageways extend .circumferentially of the axis of the fumace. Due to the fact that inwall or mantle plates areconstructed and arranged for the circulation of the cooling water circumferentially of the inwall or'mantle, they are usually disposed well within the refractory brickwork thereof.

Being entirely buried within refractory brickwork which is enclosed by a Jacket of heavy metal plates, and having no communication with the.

exterior of the furnace except by way of their water intake and outlet conduits, they cannot be removed and replaced in the manner of :bosh

plates without rebuilding the walls they serve to cool. I

Early si ns of inwall or mantle plates comprised castings provided with integrally cast elongated neck portions extend to the exterior of the furnace. Due to the factthat these integral elongated neck portions were, like the body portions of the plate, comwhich were adapted to posed of cast material, they frequently gave trouble in their capacities as water intake and outlet conduits due to the leakage caused by blow holes inherent in the casting operation or to cracking at their points of connection with the said body portion. defects causing leakage can be materially reduced by extreme care in the casting technique, there is ever present the possibility of cracking at those points where the integral elongated neck portions connect with the body portion of the cooling plate. This danger cannot be eliminated for the reason that the body portions of the plate tend under extremely high temperatures to move with the wall, thereby subjecting the integral elongated neck portions which extend to the exterior of the furnace to high shearing stresses.

Because of the foregoing difllculties which are indigenous to inwall or mantle plates provided with integrally cast elongated neck portions, it

became prevalent practice in case of a failure to introduce through the water conduits cement or the like, whereby the cooling plate, having failed in its capacity as a cooling medium, was permitted to contribute somewhat to the refractory qualities of that portion of the wall in which it is disposed.

In our Patent No. 2,252,605, dated August 12, 1941, we have disclosed and claimed a cooling plate for blast furnace inwalls and mantles which eliminates the integrally cast elongated neck portions of the prior art and substitutes therefor protection pipes which extend from the body portion of the cooling plate to the exterior wall of the furnace, together with water conduits which are telescoped therein. These protection pipes are so connected to the body portion of the cooling plate as to provide some flexibility. This permits the body portion of the cooling plate to move with the wall within which it is buried without shearing the protection pipes which extend to the metal jacket on the exterior thereof. In addition, the water conduits which extend through these protection pipes are detachably secured to the fluid intake and outlet connections for the body portion of the plate whereby the conduits may be easily replaced whendamaged.

While blow holes and other Patent N to James L. Wick, Jr.,' dated August 12, 1941, discloses and claims a construction similar to that of the Wick and Nesselbush patent identified hereinbefore, but differs therefrom in the provision of flexibility in the protection pipes per se. This permits the inner ends of the protection pipes to be connected to the body portion of the cooling plate either flexibly or rigidly without incurring shearing stresses at these points.

As is well known to those skilled in the art, the high temperatures of the furnace cause crumbling, spalling and fusion of the bricks comprising the walls of the inwall and mantle. This tendency toward disintegration is furthered by the reaction of the furnace gases with the brickwork. In addition, the contact of the coke with the interiors of the walls of the inwall and mantle causes much wear. These combined factors frequently cause the disintegration of the interiors of the walls of the inwall and mantle to such an extent as will expose the most adjacent portions of the cooling plates therein.

So long as a blast furnace embodying the inwall or mantle plates of either of these patents is operated safely within the limits prescribed by the thickness and construction of the refractory brickwork of the inwall or mantle, the advantages aflorded thereby will be realized. If, however, the furnace is operated over a protracted period of time, the disintegration of the interiors of the walls of the inwall and mantle will progress beyond the point where the most adjacent portions of the cooling plates will be exposed and ultimately result in the destruction of the support for the said plates.

When the disintegration of the refractory brickwork immediately below an inwall or mantle plate progresses to an extent sufficient to impair the support afforded thereby, the extreme weight of such a plate makes it tend to drop down into the furnace, and this tendency is only restrained by those instrumentalities associated therewith which extend to the interior of the furnace. In

- the case of cooling plates for inwalls and mantles neck portions to crack at their points of connection with the body portions of the plate is dangerously increased. As before stated, the patented designs referred to hereinbefore contemplate not only the attachment of the water conduits to the plate, but incorporate therewith flexibility in the protection pipes per se and/or at their points of connection with the body portions of the cooling plates. While the water conduits aiford some resistance to any tendency of the body portions of the cooling plates to drop into the furnace, it may be that the flexibility therein or afforded thereby would result in impaired resistance to tensional stresses at the point or points of flexibility.

In accordance with the teachings of the present invention, there is provided for disposal in either the inwall or mantle of the furnace a cast elongated relatively flat hollow cooling plate generally indicated at 6. In plan, the cooling plate 6 is shaped like a segment of a cylinder, the curvature thereof being such as will conform to the contour of that portion of the inwall or mantle in which it is, in the erection of 'the furnace,

to be buried. The inner edge, and accordingly that which is most adjacent the axis of the furnace, is therefore concave, as shown at 1, while the opposite andiouter edge is concentrically and necessarily convex, as shown at 8. Adjacent one of the ends of the convex outer edge 8 of the cooling plate 5 is a pair of openings l2 and I3, the former providing a. water intake passage and the latter providing a water outlet passage. Cast integrally with the cooling plate 6 and extending from between the water intake passage l2 and the water outlet passage l3, and longitudinally of the plate, is a centrally disposed baffle plate I whereby there is permitted the circulation of water from the intake l2 through the outlet l3 in the direction of the arrows of Figure 3. As will be seen, the flow of incoming water and also the flow of outgoing water on the opposite side of the baille plate H is in a direction circumferentially of the wall in which the cooling plate 6 is buried. Extending inwardly from the interior of the wall through suitable passages in the refractory'brick-work thereof is a pair of water conduits I6 and II, which respectively communicate with the water intake passage I2 and the water outlet passage |3.- In lieu of directly screw-threading the water conduits Hi and I1 into the convex outer edge 8 of the cooling plate 6, there is cast integrally with the said convex outer edge and peripherally of each of the water passages a circular boss portion I8. Into each of these boss portions l8 one of the water conduits l6 or I! is screw-threaded to a substantial depth,

but not entirely through the corresponding water passage l2 or I3. Such construction, coupled with the fact that the circular boss portions l8 provide a substantial wall thickness, permits rethreading to a greater depth, or, if desired, to a greater diameter, whereby thewater conduits l6 and I1 may be removed and replaced with either pipes of the same diameter in the event of rethreading to a greater depth, or, if desired, to a larger diameter. This is particularly important, as very frequently water conduits break adjacent the inwall or mantle plate during the ordinary operation of the blast furnace.

It will be understoodby those skilled in the art that in lieu of providing the water intake and water outlet at one end of the cooling plate, and in spaced but substantially adjacent relationship with respect to each other, the said passages may be disposed at opposite ends of the said plate.

The foregoing construction and arrangement of parts is embodied to a large extent in the two patents hereinbefore mentioned. However, the teachings of the present invention additionally comprise the formation on the outer ends of the integrally cast circular boss portions l8 of integrally cast flanges l9, and associated instrumentalities which will be described hereinafter.

Referring to Figure 4, it will be perceived that not only are the circular boss portions l8 of materially greater thickness than the walls of the body portion of the cooling plate 6, but also the thickness of the flanges l9 which are integrally cast with the said boss portions. This is of particular importance as will appear more fully hereinafter.

Disposed to extend through the passageways to the exterior of the furnace which are occupied by the water conduits I6 and I1, and in telescopic relationship therewith, are protection pipes 20, each of which has integrally formed on its inner end a flange 2|. These protection pipes 20 and the flanges 2| which are integrally formed on the inner ends thereof are composed of forgings,

i. e., the pipes per se may be hot-rolled with the flanges 2| produced by an upsetting operation,

or, if desired, the saidflanges may be fabricated as by welding, etc. It is to be particularly noted that the protection pipes 20 and their flanges 2| are composed of forgings (as distinguished from castings), and they therefore possess the wellknown characteristics of hot-rolling. Therefore the protection pipes and their flanges are more ductile and possessed of greater strength than any part of comparable cross-sectional area of the casting which comprises the body portion of the cooling plate 6. Accordingly, if the integrally cast circular boss portions l8 of the cooling plate 6, and the flanges IQ of the latter, were of the same cross-sectional area as the protection pipes 20 and their flanges 2|, the cast elements would be materially weaker. However, this situation is avoided by the increased cross-sectional areas of the cylindrical portions l8 and their flanges l9.

In order to rigidly connect the flanges IQ of the circular boss portions l8 of the plate 6 with the flanges 2| on the inner ends of the protection pipes 20, bolts 22 are extended through the said flanges and are engaged by nuts 23 on the projecting ends thereof.

In the event-that disintegration of the interior of the walls of the inwall or mantle takes place to such an extent as indicated by the dotted lines X of Figure 1, the extreme strength afforded by the forged protection pipes 20, and the manner of their connection'with the cast plate 6 through the medium of the elements l8 and I9 of increasedcross-sectional area, will rigidly support the plate. At the same time, the very nature of the forged protection pipes 20 and the integrally formed flanges 2| on the inner ends thereof permit of slight deformation to accommodate to a limited extent the movement of the plate with the wall relative to the exterior of the furnace.

The locations of the flanges IS on the outer ends of the foreshortened circular boss portions l8 permit of the disposition between the said flanges and the convex outer edge 8 of the cooling plate of refractory material whereby the flanges serve to anchor the cooling plate against movement downwardly into the furnace. This construction also serves to anchor the protection pipes 20 whose flanges 2| contact the flanges IQ of the foreshortened cylindrical portions I8 in the event that the said protection pipes tend to move toward the cooling plate 6. It will be understood, of course, that the outer ends of the protection pipes 20 may, if desired, be secured against sliding movement toward the flanges IQ of the cooling plate, either by way of attaching the same to the jacket 5 of heavy metal plates, or otherwise.

Other modes of applying the principles of the invention may be employed, changes being made as regards the details described, providing the features stated in any of the following claims, or the equivalent of such, be employed.

We claim:

1. In a metallurgical blast furnace comprising a refractory stack extending above the mantle thereof, a hollow cooling plate buried within the wall'of said refractory stack whereby refractory portions of the said'stack are provided between the inner and outer walls thereof and the said hollow cooling plate, the exterior wall of said 7 stack having a pair of passages communicating with said hollow cooling plate, fluid intake and fluid outlet connections for said hollow cooling plate, each of said connections being in align- 75 ment with one of said passages and terminating inwardly of the exterior wall of said stack, a rigid protection pipe disposed in each of said passages and rigidly connected to said hollow cooling plate, and fluid intake and outlet conduits extending through said rigid protection pipes and detachably secured to their respective connections on said hollow cooling plate whereby said conduits may'be easily replaced when damaged, etc., said rigid protection pipes being-comprised of forged wall of said refractory stack whereby refractory portions of the said stack are provided between the inner and outer walls thereof and the said hollow cooling plate, the exterior wall of said stack having a pair of passages communicating 20 with said hollow cooling plate, fluid intake and fluid outlet connections for said hollow cooling plate, each of said connections being in alian-' ment with one of said passages and terminating inwardly of the exterior wall of said stack, a, rigid protection pipe disposed in each of said passages and secured against sliding movement toward said hollow cooling plate, said rigid protection pipes being rigidly connected to said hollow cooling plate, and fluid intake and outlet conduits extending through said rigid protection pipes and detachably secured to their respective connections on said hollow cooling plate whereby said conduits may be easily replaced when damaged, etc., said rigid protection pipes being comprised of fored metal to thereby enable limited deformation while providing substantial resistance to shearing stresses.

JAMES L. WICK, JR. LOUIS M. NESSELBUSH.

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