COOLED FURNACE ACCESSORIES

Abstract: A furnace accessory of which the whole or part requires to be cooled in use (e.g. a tuyere, a plate cooler or a stave cooler for a blast furnace or an electric clamp or shoe for an electric furnace) incorporates one or more heat pipes (21) so disposed as to conduct heat from a first position in the accessory to a second position relative to the accessory, from which second position heat can be removed from the heat pipe.

Description: Title: COOLED FURNACE ACCESSORIES 2 " " TECHNICAL FIELD " - - Thlϋ invention is- concerned -wi±h furnace accessories, and more particularly with furnace accessories of which the whole or part requires to be cooled in use, e.g. to prevent heat damage to the accessory or to remove heat from adjacent refractory material. Examples of such accessories are tuyeres, plate coolers and stave coolers for blast furnaces and electric clamps and shoes for electric furnaces. BACKGROUND ART Conventionally, furnace accessories are cooled by circulating water through cavities in the accessories and the cavities are disposed so that the cooling water can extract heat from the hottest parts of the accessories. DISCLOSURE OF INVENTION It is an object of the present invention to provide means for improving the cooling of furnace accessories. According to the invention, a furnace accessory incorporates one or more heat pipes so disposed as to conduct heat from a first position in the accessory to a second position relative to the accessory, from which second position heat can be removed from the heat pipe. As is well known, a heat pipe comprises a sealed casing containing a volatile material. One area of the casing is arranged to receive heat from a heat source so that the volatile material in that area evaporates and another area of the tube is arranged to be cooled so that the vapour there condenses. Thus, within the casing vapour passes from the heated area to the cooled area carrying heat as latent heat between.the two areas. Condensed volatile material is recirculated from the cooled area to the heated area. The casing may OMPI /., IPO . be of various forms, e.g. an elongated cylinder, a curved tube or an annular .-tube. Normally, the first position will be in a part (e.g. a nose) of the accessory which is subjected to 5 the highest temperatures in use. The second position may be in a cavity in the accessory through which cooling fluid can ' be circulated to remove heat from the heat pipe. Alternatively the second position may be outside the body of the accessor 10 so that the heat pipe can be cooled by radiation and/or the application of cooling fluid outside the accessory body. Furnace accessories are usually made of copper and by casting. In the present invention, internal 15 holes are preferably provided in the accessory body , and the heat pipe or pipes are accommodated in the holes or in tubes (e.g. of copper) in the holes. The heat pipe or pipes may be inserted in smooth bores in the holes or tubes so as to be a close fit therein (e.g. a shrink 20 fit) or have screw-threads so that they can be screwed into screw-threaded bores. BRIEF DESCRIPTION OF DRAWINGS The following is a description by way of example of various embodiments of tuyeres for blast furnaces in 25 accordance with the invention, reference being made to the accompanying drawings, in which Fig. 1 is a longitudinal section through one embodiment, *-•-• Fig. 2 is a section on the line 2-2 of Fig. 1, 30 Fig. 3 is a longitudinal section through a second embodiment, Fig. 4 is a section on the line 4-4 of Fig. 3, Fig. 5 is a longitudinal section through a third embodiment, 35 Fig. 6 is a longitudinal section on the line 6-6 OMPI IPO of Fig. 5, Fig. 7 is a longitudinal section through a fourth embodiment, and Fig. 8 is a longitudinal section through a fifth 5 embodiment. BEST MODE OF CARRYING OUT THE INVENTION In each embodiment, the tuyere comprises a hollow annular body 10 cast from copper having a central through passage 11, a nose 12; a rear end 13 and an 10 annular cavity 14 for the passage of cooling water. In the embodiments of Figs. 1 to 7, openings 15 and 16 are provided in the rear ends 13 for the entry and outlet of cooling water to and from the cavities. In the embodiment of Fig. 8, a separate annular nose cavity 17 is provided 15 and openings 18 (only one of which is shown) are provided in the rear end for the entry and outlet of cooling water to and from the cavity 14 and openings 19 (only one of which is shown) are provided in the rear end to which are connected pipes 20 leading to the nose cavity to 20 circulate cooling water therethrough. In Figs. 1 and 2, heat pipes 21 are provided in holes equi-distantly spaced round the inside of the nose 12 and extend into and terminate in the cavity 14. The holes may be produced during casting as cored 25 holes formed by the use of copper pipes 21a into which . the heat pipes are inserted. The pipes 21a may be smooth bored, in which case the heat pipes would be a shrink fit to make a water tight seal, or internally ' - ; ■ threaded, in which case the seal would be obtained by 30 screwing the heat pipes into the pipes 21a. The holes may be produced so as to open through the nose end of the casting, so the heat pipes can be inserted through that end whereafter an annular capping plate 12J is welded over the nose end. Alternatively, 35 the copper pipes 21a may be sealed at their inner ends - 4 - 21b, thus ensuring that water cannot leak from the cavity 14 into the nose and making it unnecessary to have a capping plate. In another alternative construction, the body 10 is cast with an open rear end 13. The aforesaid holes are bored from the inside of the body and terminate short of the end of the nose, so that a capping plate is not required. The heat pipes are then inserted through the open rear end and an annular base is welde on to the rear end to ensure a water tight unit. In y another construction, the holes may open through the nose so that the heat pipes can be inserted, whereafte the holes at the nose end are closed_by plugging or welding. In Figs. 3 and 4, two heat pipes are provided. Each heat pipe has a substantially semi-circular portion 23 in the nose 12 and a straight leg 24 extending into and terminating in the cavity 14. If necessary, the nose can be cast as a separate member round the heat pipes and then welded to the remainder of the tuyere. In Figs. 5 and 6, a single heat pipe 25 is provided of annular form disposed at one end in an annular internal recess in the nose and terminating at the other end in the cavity 14. In Fig. 7, the general arrangement is similar to that of Figs. 1 and 2, but in this embodiment the heat pipes 26 extend back through the cavity 14 and terminat in recesses in the rear end 13. Holes to receive the heat pipes may be cast or bored into the nose part 12a.. The heat pipes will be inserted through holes in the rear end into the holes in the nose part 12ji after a capping plate 12b_ has been welded on. The holes in the rear end will be plugged with threaded plugs or closed by welding. If required, the nose can be made in one OM • - 5 - piece and holes in the nose part .bored through the rear end, following which the heat pipes would be inserted. It is possible with this construction that some heat pipes may. fail, but the tuyere would still operate with the possibility that a number of heat pipes could be recovered and re-used. In Fig. 8, heat pipes 27 are arranged similarly to those in Figs. 1 and 2 but extend into and terminate in the nose cavity 17. The cooling water in the nose cavity will absorb the heat from the heat pipes, but in the event of failure of the nose the tuyere would still operate, after which the tuyere could be returned to the supplier and undamaged heat pipes recovered. It is also possible that if the cavity 14 failed but. the pipes 20 remained intact, the nose cavity 17 would still provide sufficient cooling. INDUSTRIAL APPLICABILITY Potential advantages of the arrangements described above are:- (a) The operating life of the furnace accessory is prolonged. Cb) Less cooling water is required, (c) The accessory can be removed after failure and new heat pipes can be fitted. (d) Although the initial cost is high, the replacement cost would be relatively low. As well as being applied in tuyeres for blast furnaces as described above with reference to.the drawings, the invention may be applied in other furnace accessories of which the whole or part requires to be cooled in use, for example in plate coolers and stave coolers for blast furnaces and electric clamps and shoes for electric furnaces. O PI__

Claims: . ' CLAIMS 1. A furnace accessory of which the whole or part requires to be cooled in use characterised in that the accessory incorporates one or more heat pipes so disposed as to conduct heat from a first position in the accessory to a second position relative to the accessory, from which second position heat can be removed from the heat pipe. 2. A furnace accessory according to claim 1 wherein the first position is in a part of the accessory which is subjected to highest temperatures in use. 3. A furnace accessory according to claim 1 or claim 2 wherein. the second position is in a cavity in the accessory through which cooling fluid can be • circulated to remove heat from the heat pipe. 4. A furnace accessory according to claim 1 or claim 2 wherein the second position is outside the body of the accessory so that the heat pipe can be cooled by radiation and/or the application of cooling fluid outside the accessory body. 5. A furnace accessory according to any preceding claim wherein each heat pipe is accommodated in an internal hole in the accessory body. 6. A furnace accessory according to claim 5 wherein each heat pipe is accommodated in a tube in said hole. 7. A furnace accessory according to claim 5 or claim 6 wherein the heat pipe is inserted in a smooth bore in the hole or tube so as to be a close fit therein. 8. A furnace accessory according to claim 5 or claim 6 wherein the heat pipe is screw-threaded and screwed into a screw-threaded bore in the hole or tube. 9. A furnace accessory substantially as hereinbefore described with reference to the accompanying drawings. OMP /,, IP

Inventors: PEEL E
Applicants: PEEL E, PEEL JONES COPPER PROD LTD
Application year: 1979
Main classification: F27D1
IPC codes: C21B7, F27D1, F27D9