CA1135959A - Cooling plate for furnaces - Google Patents

Abstract

D-6799 (Schnei) COOLING PLATE FOR FURNACES

ABSTRACT OF THE DISCLOSURE

A copper or copper alloy ingot is forged or rolled into a plate; blind bores are deep-drilled into the plate from one of its narrow edges and plugged; inlet and outlet nipples for the ducts are provided on the rear surface; and the front surface of the plate is provided with grooves or short sleeves for holding a fireproof lining structure or material.

Description

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!l , Il D-6799 (Schnel) L BACKGROUNl:) OF THE INVENTION
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3¦ The present invention relates to a flat,cooling device to be used in a pit furnace such as a blast furnace, 5l or the like, having a fireproof lining or casing; and more 61l particularly, the invention relates to a copper plate or a 71~ low-alloyed copper plate -to be used for cooling such a furnace 8l¦ and having internal cooling channels.

10l Flat cooling devices or plates of the type to which 11¦ the invention pertains are usually arranged between the shell ~ of such a furnace, e.g., a blast furnace, and a brick lining I ~;
1~ thereof. The cooling ducts or channels are connected to a 1~ ¦ suitable circulation system for a coolant. The cooling pla-tes themselves are covered on one side with a fireproof lining, 16 ' the side being the one facing the interior of the furnace.

18 ~ Plates for cooling, having the foregoing features, are 19 I known to be made of cast iron; and pipes are embedded 20 I therein. The heat transfer through these plates is quite ¦
21 I poor for two reasons. For one, the thermal conductivi-ty 22 I of cast iron is rather low; the other reason is an added 23 I resistance against heat flow across the pipe-plate interface;
24 I there may even be a gap, oxide layer, or both.
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D-6799 (Schnei)~

11~ In some cases, the brickwork of the furnace casing 2l is damaged, deteriorates with age, etc., so that the inside 3l surface of the cooling device is, locally at least, directly 4l~ ex?osed to the hot furnace chamber. Since the operating 5 1I temperature of a blast furnace is well above the mel-ting 6 ¦I point of cast iron and since the poor hea-t transfer condi-7 I tions through the plate (supra) do not lead to adequate 8¦ cooling of the inside surface of the cast iron plate, the I ....
9 , plate will wear out and deteriorate rather rapidly. Thus, 10ll the life of such a cooling device is quite limited.
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12¦ Another known variety of cooling plates is made of 13 j! cast copper, either being directly provided with internal 1~ I cooling ducts, or tubes for the coolant are embedded 15 I in the cast. The texture of cast copper is not as . ~
16 I homogenic and dense as the text;ure of forged or rolled I¦ copper. Thus, the heat transfer throuyh cast copper is not 18 I as good as through a denser and more homogenic copper. Also, cast copper is not as strong. Moreover, separate, embedded 20 , cooling tubes inevitably carry an oxide layer which impedes 21 I the heat transfer into the tubes. On the other hand, inte-22 I gral ducts in cast copper plates have frequently rather rough 23 ¦ walls and uneven surfaces. The surfaces may even carry 24 ~ embedded sand from the casting. All of these features , reduce the heat: trassfer into the ducts.

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' D-67g9 (Schnei) 1¦, DESCRIPTION OF T~IE INVENTION

31 It is an object of the present invention to provide a new and improved cooling plate for furnaces in order to 51~ improve cooling conditions for a fireproof furnace lining and 61i a-furnace jacket.
71, 81 - In accordance with the preferred embodimen-t of the 5i invention, it is suggested to provide a copper,or low-alloyed lO1, copper-alloy ingot and to forge or roll this ingot into a ll plate. Preferably,the plate is straightened thereafter.
12 1 Next, blind bores arç deep-drilled into the plate to extend }3 1 from one narrow edge almost to the opposite edge, running directly l4¦¦ underneath and parallel to the wide flat surfaces of the : 15 1l plate. The plate is preferably provided, in addition, with ¦
1.6 ¦! means for holding fireproof material. Moreover, connections l~ to the bores (the drilling endshaving been closed) are made 18 to pass a coolant therethrough; preferably, short ducts are 19 drilled from the rear side of the plate to the drilled bores and near the two ends of each such bore. Short tubes or 21 sleeves are welded to these ducts as extensions thereof and 22 for the purpose of connecting the plate with the ~ores into ; 23 the flow path of a coolant.

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The cooling plate, as per the invention, is much 26 denser, and very homogenic, as compared with a cast copper plate. !

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, D~6799 (Schnei) 1l Cast copper plaites include fre~uently shrink holes, 2I resulting in voids. No such voicls will be found in forged ~ !~ or rolled plates. The novel plates are stronger, and the 4 ¦I thermal conductivity is not only higher but more uniform 5 1l throughout the material. The bores will, more readil~, have an 6 ¦1 accurately predetermined disposition, orientation, and spacing 7 ¦I so that the heat transfer conditions can be better predeter-~¦¦ mined.

10ll The side of the cooliny plate facing the interior of 11¦l the furnace ls usually to be lined or covered with fireproof 12¦l bricks, or another fireproof material. The surface portion 1 131 directly exposed to the furnace chamber is thus reduced.
1~l Should some of the fireproof lining, or a part thereof, break 15 j off, the heat transfer-out of the furnace-chamber would 16 I be limited so that the chamber itself would not be cooled unduly.
17 I This is an important fact as any outflow of heat from the 18 furnace chamber has to be compensated by additional heating 19 I for reaso~ of metallurgy. Nevertheless, the plates must be .
20 ! cooled sufficiently to maintain their temperature,well below 21 ! the softening point of-copper. ~ -22 ! - -27 I ;
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~ D-6799 (Schnei) 1 ¦I DESCRIPTION OF THE DRAWINGS

3,l While the specification concludes with claims, parti-Ll¦l cularly pointing out and distinctly claiming the subject matter 5 ¦I which is regarded as the invention, it is believed that the 6 11 invention, the objects and features of the invention, and 1.
7 1I further objects, fea-tures, and advantages thereof, will be I ~;
~11 better understood from the following description taken in 9~1 connection with the accompanying drawings, in which:
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11 ¦ Figure 1 is a side elevation of a flat cooling device 12 I in accordance with the preferred embodiment of the present invention and constituting the best mode of practicing same;
l i ~ Figures 2 and 3 are section views as respectively 16 ¦ indicated by lines 2~2 and 3-3 in Figure l; .

18 I Figure 4 is a view similar to Figure 1, e~cept that 19 ¦ the plate is constructed to hold fireproof material other I :

20 I then bricks;

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22 I Figure 5 is a section view taken along line 5-5 in ~ I

Figure 4; and 2~ :~

Figure 6 is a cross-section equivalent to Figure 3, 26 but showing a modificatio~.

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~ D-6799 (Schnei) ', 1I Proceeding now to the detailed description of the invention and the drawings, a blank is made by forginy or 3¦' rolllng a block or ingot into a plate; the inyot beiny a copper ingot, or an ingot made of a low-alloyed copper alloy.
$¦ll Forging or rolling resul-ts in a very dense and homogenic ~ I texture, ensuring later a high degree of uniformity in the 7 I heat transfer through the material. The plate is sub-8 I sequently straightened to ensure proper dirnensions and 9l orientation. The plate is to be used as one of many in a lOi blast furnace, and care must be taken already during the i 11 ~ earlier manufacturing steps, so that the plate will readily fit 12 11 withothers into the wall and case s-tructure of the furnace.
13~, - - - , ~ Next, the narrow edges as well as the rear-surface 15 ¦ (to the right in Figure 2, the surface opposite the one shown 16 I at the top elevation of Figure 1) are milled. Previously, 17 short bores 32 have been drilled into the plate from the 18 I rear. Also, nipples 2 have been forged, or the like, to 19 ¦ the plate as extensions of bores 32. These nipples are not 20 I cutt off by the milling cutter.
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22 Next, blind bores 3 are deep-drilled into plate 1, 23 beginning at one small edge; the bores extend almost all 24 ¦ the way through the pla-te and end just short of the opposite 25 I edge. The open endsof the bores arethen plugged, preferably 26 I by means of screw plugs 4 which are additionally welded or 2~ , j` . ,. `. .. . .. ~.. . ` . , .

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D-6799 (5chnei) Il,, 1¦ soldered ~o ensure ~ight closure of the bores. Short tubes 21 or sleeves 5 are welded or soldered to nipples 2 to serve as ~l' e~tensions. Later, i.e., after the plate has been lnstalled '11 in a furnace, conduits will be connected to these tubes to 5 1l feed a coolant thereto, or to discharge the coolant therefrom.
6 1I For this reason, one provides these inlet and outle-t ducts 7 I (ducts 5, 2, and 32) as close as possible to the ends of ~ , bores 3~.
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10~¦ Next, grooves 6 are cu-t into the one broad side of ~ the plate- These grooves extend parallel to each other and 121i leave ridges in between. These ridges may have any kind of 13ll cross-sectional profile; but they preferably have a trape-14 ' zoidal profile to result in overhung edges. The grooves 6 15 , are thus undercut in a length direction, and they are to be 16 I filled later with a fireproof material (bricks). The under-l't ¦ cut configuration of the grooves holds and clamps these 18 I bricks in place.
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20 I After the various milling and drilling operations 21 I have been completed, the plate is straightened again. If so 22 I desired, a hook 8 for facilitating transportation is screwed 23 I into a bore of the plate. Several threaded bores 9 are 24 tapped into the plate~ preferably in a rather uniform pattern. I
Bores 9 serve to fasten the plate to the blast furnace jacket~ ¦

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The quadrllateral plate 1, as shown, tapers slightly in upward direc-tion ~as shown and oriented in ~igure 1), and Figure 2 reveals a slight inward taper of the lower edge and an outward taper of the upper edge of this plate.
All of these features are provided to better conform the plate to the contour of the furnace. The plates are mounted in the furnace with an inward inclination of the top. Also, the spacing between the various plates is uniformly small in order to obtain the desired areal cooling.
Figure 3 reveals that the long pLate edges are also tapered. It will be observed that the interior of a blast furnace has a circular cross section as seen from the top of such a furnace (not shown). Due to the taper of the long plate edge, juxtaposed plates have an angle to each other, and all plates togeth-er approximate that circular contour of the furnace by a multifaceted polygon.
As stated, bricks are shifted into grooves 6 of the plate shown in Fig ures 1, 2, and 3. The plate 1', shown in Figures 4 and 5, is constructed in such a way that it accommodates a fireproof material to be applied otherwise.
Plate 1', shown in Figures 4 and 5, is also provided with bores 3, nipples 2, tubes 5, and plugs 4 as described. However, plate 1' is thinner; and shallow, circular grooves 11 have been cut into one surface. Short sleeves 10 (or pins) are inserted in these grooves 11 and are welded to the plate.

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These sleeves 10 will serve as holders for a suitably applied fireproof lining.
The interface between the plate material and the sleeves 10 should provide for unimpeded heat flow between these parts. These conditions are estab-lished by several features. First of all, the end of each sleeve 10 abuts with the plate material. Welding seams 12, moreover, provide additional paths for heat transfer.
Bores 11 are slightly tapered (bevelled) outwardly, and the resulting V-shaped gap between the inserted sleeves 10 and the side wall of the respective groove will be filled with soldering or welding material. This way, a wide, thermal conductive path between the plate material and the sleeves will not de~
pend on accuracy of milling; but the molten welding or soldering material en-sures broad and intimate sur~ace-~o-surface contact.
It should be noted, however, that one may dispense with the grooves 11 and weld directly one front end of each sleeve 10 to the flat surface of plate 1'. The welding material or solder material should have a good thermal conduc-tivity in either case.

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~3~9~3 ,1 ' ~ D-6799 (Schnei) ,, 1l As can be seen in the various views, each bore 3 21l has two duct means at or ad~acent: to its ends, for connection 3i' to a cooling line. Alternatively/ one may drill manifold ¦, bores from the long, narrow edgec; to interconnect two or 5 ¦I more blind bores 3; -this is sho~ln by way of example in Figure 6.
~ he manifold bores, such as bore 31, may also be blind bores, 7 interconnecting two main bores 3; and the open end of bore 31, 8l¦ on its drilling side, is plugged by a plug 41, similar to-5l plug 4. A transverse duct 33 ends in a manifold duct and, thus, lo¦l drains or feeds two main coolant duct bores 3. The number 11 , of bores so manifolded may vary. The manifold ducts, such 12 ¦ as duct 31, have preferably a diameter which is larger than 13 the diameter of bores 3.

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15 I It can thus be seen that the ~arious plates as depicted 16 ~ and described exhibit optimized properties with regard to 17~ heat transfer. Particularly instrumental in this respect is 18¦ the deep drilling of cooling channels into a forged or rolled 19 I copper or copper alloy plate. The plate is quite uniformly ' ;~

20 ¦ cooled.

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22¦ :- The invention is not limited to the embodiments described 23¦ above; but all changes and modifications thereof, not con~titut 241 ing departures from the spirit and scope of the invention, are 251 intended to be included.

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Claims (15)

D-6799 (Schnei)

1. A cooling plate for pit furnaces, such as blast furnaces, comprising:
a quadrilateral, forged or rolled plate made of copper or a low-alloyed copper alloy;
deep-drilled blind bores, extending from one narrow side through the plate toward the opposite narrow side;
and means on the plate for holding a fireproof material.

2. The plate as in Claim 1, said bores being closed by soldered or welded plugs, there being duct means leading into the bores.

3. The plate as in Claim 2, the duct means including each an integral nipple and a sleeve welded to the nipple, extending from a side opposite the side having the means for holding.

4. The plate as in Claim 2, one of the duct means being near one end of the respective bore, and another one of the duct means being near the opposite end of the bore.

D-6799 (Schnei)

5. A cooling plate for pit furnaces, such as blast furnaces, comprising:
a quadrilateral, forged or rolled plate made of copper or of a low-alloyed copper alloy;
deep-drilled blind bores, extending from one narrow side through the plate, almost to the opposite narrow side;
plug means for closing the bores; and duct means disposed to communicate from one of two wide, flat sides of the plates with the blind bores, near respective ends adjacent to two of said opposite plate sides as well as adjacent to the respective plug means.

6. A cooling plate as in Claim 2 or 5, there being two duct means per bore.

7. Plate as in Claim 5, wherein at least two of the bores are interconnected by manifold duct means, the duct means provided to communicate with the manifold duct means.

8. Plate as in Claim 7, the manifold duct means having a diameter which is larger than the diameter of the bores.

D-6799 (Schnei)

9. A plate as in Claim 5, wherein the other one of the two flat sides includes means for holding fireproof material.

10. A plate as in Claim 1 or 9, the means for holding being short, circular elements welded to the plate.

11.A plate as in Claim 1 or 9, the means for holding being grooves in one surface of the plate, the grooves extending transversely to bores.

12. The method of making a cooling plate, comprising the steps of rolling or forging a copper or copper alloy ingot into a quadrilateral plate;
deep-drilling long, blind bores into the plate, beginning from one small edge of the plate and extending almost to the opposite small edge;
plugging the blind bores from their respective open end; and providing lateral inlet and outlet duct means for the bores in the plate and from one of its flat surfaces.

13. A method as in Claim 12 and including the step of straightening the plate at least once after the rolling and forging step.

14. A method as in Claim 12 or 13, including working the edges and the one flat surface by milling.

15. A method as in Claim 13 and including milling grooves into the opposite flat surface.