Furnace with refractory bricks that define cooling channels for gaseous media

Abstract

A furnace is provided suitable for metallurgical processes, comprising at least one section comprised of refractory bricks with an outer shell plate adjacent to the refractory bricks, including exterior bricks whose external faces adjacent the shell plate define gaseous media cooling channels extending along the exterior of the refractory bricks between them and the shell plate. The furnace further comprises cooling plates within the cooling channels and joints between the successive courses of bricks. Advantageously, the conductivity of the cooling plates is at least 5 times the conductivity of the refractory lining into which it is inserted. Suitable materials include copper and copper-based alloys, brasses, bronzes, cast irons, aluminum alloys, silver, high-temperature steels, refractory metals and their alloys, graphite, silicon carbide, and aluminum nitride.

Claims

1. A furnace suitable for high temperature processes, comprising: a crucible, defining at least a hearth and a wall, the crucible having an inner refractory lining, and an outer support structure adjacent to and supporting at least a portion of said refractory lining; said refractory lining having at least a portion with an external face adjacent to said support structure, at least a part of said refractory lining having gaseous media cooling channels, and cooling plates within the cooling channels that provide thermal contact with the gaseous media, said cooling plates extending into said refractory lining.

2. The furnace of claim 1, wherein said gaseous media cooling channels extend along the exterior of said refractory lining, between said refractory lining and said support structure.

3. The furnace of claim 2, wherein at least a portion of the refractory lining includes exterior refractory bricks having profiled external faces that define said gaseous media cooling channels.

4. The furnace of claim 3, wherein said gaseous media cooling channels are aligned with joints between successive courses of said profiled exterior refractory bricks.

5. The furnace of claim 4, further comprising cooling plates located within said gaseous media cooling channels and extending into said joints between said successive courses of said profiled exterior bricks.

6. The furnace of claim 5, wherein said channels are defined by complementary recesses along adjacent upper and lower portions respectively of successive courses of said profiled exterior bricks.

7. The furnace of claim 6, wherein said profiled exterior bricks have tapered external edges so as to define gaseous media cooling channels having a generally triangular cross section.

8. The furnace of claim 1, wherein said cooling plates are made of copper or a copper alloy, brass, bronze, cast iron, aluminum alloys, silver, high temperature steels, refractory metals and their alloys, graphite, silicon carbide, or aluminum nitride.

9. The furnace of claim 5, wherein said refractory lining further comprises internal bricks remote from said support structure, and wherein said profiled channel bricks are shorter than said internal bricks to accommodate said cooling plates in contiguous courses of said internal bricks and said profiled channel bricks.

10. The furnace of claim 1, further comprising inlets in said support structure to allow gaseous cooling media to enter said channels, and outlets to allow gaseous media to be exhausted from said channels.

11. The furnace of claim 10, wherein the inlets and outlets are concentric.

12. The furnace of claim 10, further comprising a blower for forcing gaseous media into said inlets and through said channels.

13. The furnace of claim 1, wherein the gaseous media is air.

14. The furnace of claim 1, further comprising a metallic conduit within said channels, said conduit containing said gaseous media, and said conduit thermally contacting said cooling plates.

15. The furnace of claim 14, wherein said conduit is joined to said support structure.

16. The furnace of claim 14, wherein said cooling plates are made of copper or a copper alloy, brass, bronze, aluminum or an aluminum alloy, refractory metal, graphite, silicon carbide, or aluminum nitride.

17. The furnace of claim 14, wherein said cooling plates are attached to said conduit by bolts, screws, dovetails, adhesive, or welding.

18. The furnace of claim 17, wherein said cooling plates extend within said conduit so as to be thermally contacting said gaseous cooling medium.

19. The furnace of claim 16, wherein said conduit applies a spring force to said cooling plates.

20. The furnace of claim 1, wherein said cooling plates have a protective coating resistant to corrosion, oxidation and/or liquid metal/matte or slag attack.

21. The furnace of claim 20, wherein said coating is made of nickel or a nickel alloy, chrome or chrome alloy, aluminum or aluminum alloy, silicon, silicon carbide, or any combination thereof.

22. The furnace of claim 1, wherein said refractory lining has thermocouples drilled in at various depths to monitor the thickness of said refractory lining and detect ware.

23. The furnace of claim 1, wherein the gaseous media channels are located on or in a wall of said crucible.

24. The furnace of claim 1, wherein the gaseous media channels are located on or in the hearth of said crucible.

25. The furnace of claim 1, wherein said crucible further defines a roof and the gaseous media channels are located on or in the roof of said crucible.

26. The furnace of claim 1, wherein the furnace is a metallurgical furnace.

27. The furnace of claim 1, wherein said support structure includes shell plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order that the claimed subject matter may be more fully understood, reference will be made to the accompanying drawings, in which:

(2) FIG. 1 is a side elevation view of a metallurgical furnace according to one embodiment of the invention;

(3) FIG. 2 is a cross sectional side view taken along line II-II of FIG. 1;

(4) FIG. 3 is a detailed side view of the portion of FIG. 2 indicated by circle III;

(5) FIG. 4 is a detailed side view according to another embodiment;

(6) FIG. 5 is a detailed side isometric view of a portion of the exterior of the furnace of FIG. 1;

(7) FIG. 6a is a schematic isometric view, partially cut away, of another embodiment;

(8) FIG. 6b is a cross sectional view of the embodiment of FIG. 6a;

(9) FIG. 7a is a schematic isometric view, partially cut away, of another embodiment;

(10) FIG. 7b is a cross section view of the embodiment of FIG. 7a;

(11) FIG. 7c is a detailed view of a portion of the embodiment of FIGS. 7a and 7b;

(12) FIG. 8 is an isometric view of another embodiment;

(13) FIG. 9 is a side view of another embodiment;

(14) FIG. 10 is a side view of another embodiment;

(15) FIG. 11 is a side view of another embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

(16) In the following description, specific details are set out to provide examples of the claimed subject matter. However, the embodiments described below are not intended to define or limit the claimed subject matter. It will apparent to those skilled in the art that many variations of the specific embodiments may be possible within the scope of the claimed subject matter.

(17) As shown in the drawings, the furnace 12 has rectangular side walls 14 extending between an upper portion 15 and a lower portion 16 of the furnace 12, the lower portion 16 comprising a hearth 18 and a base 20. Both the hearth 18 and side wall 14 are formed of a refractory material, preferably refractory bricks 30. Surrounding the refractory side wall, hearth and base of the furnace is a structural metal shell 22, which has an inner surface 24 in contact with the side wall 14, hearth 18 and base 20, and an opposed outer surface 26 in contact with support columns 28.

(18) The refractory bricks 30 of side wall 14 are of two types: regular bricks 32 (which have a conventional rectangular prism or cuboid shape), and specially shaped channel bricks 34 which have tapered outer edges 36. In the embodiments of FIGS. 3 and 4, the contiguous tapered edges 36 of successive courses of channel bricks 34 define with the shell 22 generally wedge shaped horizontal cooling passages 40. Gaseous cooling media such as air is introduced by means of a blower (not shown) through inlets 60 which communicate with the cooling channels 40. The gaseous cooling media passes horizontally along the cooling channels 40 absorbing heat from the side wall 14 and is subsequently exhausted through outlets 62.

(19) In the embodiment shown in FIG. 3, copper cooling plates 50 are sandwiched between successive courses of channel bricks 34, and extend outwardly into the cooling passages 40. The channel bricks 34 are slightly shorter than the regular bricks 32 to accommodate the cooling plates 50 while maintaining alignment of the channel bricks 34 and the regular bricks 32 in the same course. The cooling plates 50 increase cooling of the side wall 14 by conducting heat outwardly to the cooling passages 40 where the heat is transferred and removed by convection.

(20) In the embodiment of FIG. 4, similar horizontal cooling passages 40a are defined by the shell 22 in combination with groove sides 36a in the external face of the channel bricks 34a.

(21) There are a number of possible inlet and outlet configuration which can be applied to an gaseous media cooling system in a circular furnace. For example, one or more inlets may be provided at one end of the wall, and one or more outlets may be provided at the other end of the wall, such that the gaseous media circulation paths 62, 64 extend horizontally along the wall between the inlet(s) and the outlet(s). Alternatively, each end of the wall may be provided with one or more inlets, with the gaseous media flowing toward one or more outlets located centrally between the ends of the wall. It will be appreciated that other inlet/outlet configurations are possible.

(22) When applied to a rectangular furnace, a separate cover member is preferably applied to each wall being cooled, with each wall preferably being provided with at least one inlet and at least one outlet. It will be appreciated that the cooling system can also be applied to circular or oval furnaces.

(23) Turning to FIGS. 6a and 6b, the wall 114 of a furnace comprises a plurality of bricks 132, 134 which are laid such that in alternative successive courses of bricks, a gap is provided between the edge of the brick 134 and the inner wall of the shell 122 defining a cooling channel 140. Gaseous cooling media passes horizontally along the cooling channels 140 absorbing heat from the side wall 114 and subsequently exhausting it through outlets. Cast in cooling rods 199 extend through the bricks 132 and into the cooling channels 140. The cast in rods 199 enhance the cooling.

(24) Turning to FIGS. 7a and 7b, bricks 234 have tapered edges 236 defining wedge shape channels 40 similar to the embodiment shown in FIG. 3. Copper cooling plates 250 are sandwiched between successive courses of bricks 234. In this case, the cooling plates 250 terminate in fingers 299 that extend into the cooling channels 240 to enhance the cooling effect.

(25) The present subject matter can be applied such that the cooling channels are shaped as circular, rectangular, or any shape which can be readily formed or cut into a refractory brick or cast refractory. The cooling channels may be oriented horizontally, vertically, or diagonally.

(26) Another embodiment is shown in FIG. 8, where a metallic cooling media conduit 241 is inserted into the cavity formed by the bricks 242. Conductive cooling plates 243 are inserted between the bricks and connected to the cooling media conduit 241. The plates are attached either by welding, bolts, dovetails 244, or clips to maintain thermal contact. Advantageously, the connection is designed such that thermal expansion increases the contact pressure.

(27) Another embodiment is shown in FIG. 9, where a metallic cooling media conduit 245 is inserted into the cavity formed by the bricks. Conductive plates 246 are inserted between the bricks and clamped by the cooling conduit 245. Clamping force is exerted by welding, bolts, clips 247, or by forming the cooling media conduit 245 so as to produce a clamping spring. Advantageously, the connection is designed such that thermal expansion increases the contact pressure.

(28) Another embodiment is shown in FIG. 10, where a metallic cooling media conduit is 248 inserted into the cavity 249 formed by the bricks. Conductive cooling plates 250 are inserted between the bricks and penetrate the conduit 248 so as to be in direct contact with the cooling medium. Clamping force is exerted by bolts, clips 251, or by forming the channel so as to produce a clamping spring. Advantageously, the connection is designed such that thermal expansion increases the contact pressure.

(29) Another embodiment is shown in FIG. 11, where the cooling media conduit 252 is inserted into a cavity positioned at an intermediate point between the cold face 253 and the hot face 254 of the lining. Conductive plates 255 are inserted between the bricks and connected to the conduit 252. The plates 255 are attached either by bolts, dovetails 256, or clips to maintain thermal contact. Advantageously, the connection is designed such that thermal expansion increases the contact pressure.

(30) While the gaseous cooling media is typically air, in some embodiments, the cooling media may be nitrogen, carbon dioxide or an inert gas to prevent oxidation of the cooling channels, conductive plates or unwanted reactions in the process vessel.

(31) It will be appreciated by those skilled in the art that many variations are possible within the scope of the claimed subject matter. The embodiments that have been described above are intended to be illustrative and not defining or limiting.

(32) For example, while the embodiments above refer to furnace walls, the present subject matter could also be applied to hearths or roofs formed from refractory bricks mounted by an outer shell.