Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B7/00—Blast furnaces
  • C21B7/10—Cooling; Devices therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/12—Casings; Linings; Walls; Roofs incorporating cooling arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D9/00—Cooling of furnaces or of charges therein
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0233—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes the conduits having a particular shape, e.g. non-circular cross-section, annular
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0275—Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
  • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
  • F28D2021/0077—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for tempering, e.g. with cooling or heating circuits for temperature control of elements
  • F28D2021/0078—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for tempering, e.g. with cooling or heating circuits for temperature control of elements in the form of cooling walls
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• the present invention generally relates to cooling equipment for furnaces, and more specifically to cooling staves for use in a metallurgical furnace.
• the invention relates to a cooling stave intended in particular but not exclusively for use in a shaft furnace, especially in a blast furnace for pig iron production.
• Cooling staves also called “stave coolers”, “cooling plates” or simply “staves” have been used in blast furnaces for decades to protect the furnace armor. They are arranged on the inside of the furnace armor, i.e. the furnace shell, and typically have internal coolant ducts, which are connected to the cooling system of the furnace.
• the coolant ducts are usually formed either by separate cast-in coolant pipes or, to reduce thermal resistance at the interface, by drilled-in or cast-in internal passages.
• the "hot face”, i.e. the stave surface facing the interior of the furnace is typically lined with a refractory material to isolate the stave from the process environment.
• Cast iron (or steel) staves on the other hand have often proved not sufficiently conductive to be used in the lower region of today's high-capacity furnaces, where very high heat loads must be met. Nevertheless cast iron (or steel) staves, have significantly higher mechanical wear resistance than copper staves. In fact, copper staves can be badly damaged by abrasive unreduced burden in case neither their refractory lining nor a protective scaffold is intact. Moreover, copper staves are more prone to deformation due to uneven thermal loads, such deformation increasing the risk of damage to the stave.
• U.S. patent application 2008/01 1 1287 proposes a modified stave design, in which the stave is devoid of usual internal coolant passages (that are connected to the cooling circuit).
• US 2008/01 1 1287 proposes to install an arrangement of heat pipes that extend from inside the stave plate body to a heat sink outside the furnace shell, where the heat pipe is safely connected to the coolant circuit. Accordingly, in such a stave, the condensation end portion of the heat pipes is arranged outside the furnace shell, while only their evaporation end portion is arranged within the plate body of the stave. Similar designs have been proposed in German laid open publication no.
• the stave designs according to WO 80/01000 and US 4'561 '639 also comprise a plate body made of metallic material with a front face facing the interior of the furnace.
• these staves still include an internal (water) coolant passage within the plate body, the passage being connected to the furnace cooling circuit in typical manner.
• a set of heat pipes is associated to the coolant passage, the heat pipes being arranged in the plate body to improve heat transfer from the front face ("hot face") to the internal coolant passage. Accordingly, heat conductivity is improved, so that a risk of mechanical failure is reduced.
• a cooling stave as claimed in claim 1 achieves this object.
• the present invention relates to a cooling stave (in short "stave") for protecting the shell of metallurgical furnace, in particular of a blast furnace.
• the cooling stave comprises a plate body made of metallic material.
• the plate body has a front face and an opposite rear face, the faces respectively facing the interior of the metallurgical furnace and facing the shell when the stave is installed.
• at least one internal coolant passage is provided within the plate body, the coolant passage having a main portion, which is usually but not necessarily rectilinear and of cylindrical cross- section.
• a set of heat pipes is associated to at least one of the coolant passages, typically to each coolant passage.
• Each heat pipe has an evaporation end portion and a condensation end portion.
• the set of heat pipes is arranged in the plate body to improve heat transfer from the front face, i.e. from the "hot face” to the opposite "cold face” in general, and more specifically to the associated coolant passage.
• each heat pipe of the set of heat pipes is arranged within the plate body, i.e. without protruding notably from the plate body, and further arranged with its condensation end portion partially enclosed or fully enclosed in plate material contiguous to the associated coolant passage. That is to say the condensation end portion of each heat pipe is either partially surrounded or wholly contained (embedded) in the plate material without, in either case, protruding into the coolant passage. Accordingly, during operation, heat transfer from the condensation end portion to the coolant passage occurs through the metallic material contiguous to the coolant passage. In other words, the condensation end portions are cooled, indirectly, by means of thermal conduction through an interface of metallic material of the plate body between the heat pipe and the associated coolant passage.
• the global thermal conductivity of a stave can be significantly improved, especially in case of a stave made of ferrous metal but also in case of a stave made of copper.
• Finite element calculations predict, for a cast iron stave an increase of >30% compared to a conventional cast iron stave and for a copper stave an increase of >10% compared to a conventional copper stave.
• the thermal distribution is enhanced, thus reducing a risk of plastic deformations due to excessive and nonuniform temperatures in the stave body.
• the lifetime of the stave is increased.
• the staves according to the presently claimed invention have the notable benefit of being compatible with existing designs.
• the presently proposed staves enable installation in existing furnaces (retrofitting), without major changes to the cooling installation if any, without the need to connect heat pipes to a modified cooling circuit, and without the need of creating heat pipe vacuum on-site (as probably inherently necessary with the mentioned prior art staves).
• the staves according to the presently claimed invention have the important benefit of further reducing the risk of coolant leakage into the furnace.
• cavities are provided in the stave body that communicate with the coolant passages to receive heat pipes that have their condensation end portion arranged within the coolant passage. These cavities inevitably create channels from the associated coolant passage to a portion near the front face of the stave, which channels must be reliably sealed to avoid any leakage through this channel in case of a mechanical failure, e.g. a rupture or fissure, through the cavity.
• a beneficial increase in thermal conductivity is achieved in case the plate body is made of ferrous metal, in particular of cast iron or steel. Accordingly, a stave having the combined benefits of mechanical robustness of a cast iron or steel stave together with higher thermal efficiency is obtained. . Nevertheless, a notable increase in thermal conductivity can also be achieved with copper staves.
• each set of heat pipes comprises pairs of heat pipes arranged along the longitudinal axis of the main portion of the associated coolant passage, preferably in layers at regular intervals.
• each layer may alternatively comprise a single heat pipe
• pairs of heat pipes further improve the overall thermal conductance.
• the condensation end portions of both heat pipes of each pair are advantageously arranged on opposite sides of the main portion of the associated coolant passage.
• the heat pipes of each pair are preferably arranged obliquely with respect to a front-to-rear direction and with their evaporation end portions spaced apart further than their condensation end portions.
• the heat pipes are preferably arranged in layers at the level of the retaining ribs in order to enhance mechanical protection of the heat pipes within the plate body.
• the heat pipes may be arranged with their evaporation end portion enclosed within a retaining rib in order to further reduce overall thermal conductance.
• the heat pipes may be arranged so at to not protrude into the retaining ribs for minimal exposure to mechanical stress.
• each heat pipe of the set of heat pipes extends fully within the plate body, from near the front face to near the associated coolant passage, and preferably along a direction perpendicular to the longitudinal axis of the main portion of the associated coolant passage.
• each heat pipe of a set of is also arranged with its evaporation end portion enclosed in metallic material contiguous to the front face. Accordingly, heat transfer from the front face to the evaporation end portion occurs through this interface of metallic material contiguous to the front face, so that the evaporation end portion are protected from mechanical wear.
• a first group of auxiliary heat pipes is arranged in the plate body so as to extend perpendicularly to the longitudinal axis of the coolant passage and in parallel to the front face.
• Such auxiliary heat pipes improve thermal distribution along the width direction of the plate body.
• a second group of auxiliary heat pipes may be arranged in the plate body so as to extend in parallel to the longitudinal axis of the coolant passage.
• the plate body comprises a plurality of parallel internal coolant passages, each coolant passage having a respectively associated set of heat pipes according to the presently claimed invention.
• the coolant passages beneficially have their longitudinal axis arranged closer to the rear face than to the front face, in particular within the rearmost 40% of the base wall thickness of the plate body.
• the water carrying passages (integrally formed channels or inserted pipes) in the stave are further away from the inside of the furnace. The risk of a breakthrough is thereby further reduced, and, in certain cases of a fatal failure on the front side of the stave, this design may nevertheless warrant that no water enters the furnace. Accordingly, the risk of a hydrogen explosion is lowered even further.
• the heat pipes preferably an internal wick arrangement, e.g. a sintered metal wick arrangement or an internal groove arrangement, for returning the heat pipe working agent from the condensation end portion to the evaporation end portion by capillary action.
• an internal wick arrangement e.g. a sintered metal wick arrangement or an internal groove arrangement
• the metallic plate body may comprise:
• each heat pipe of the set of heat pipes a corresponding blind bore drilled from the rear face and terminating short of the front face, each heat pipe being fixed in thermally conductive manner within its corresponding blind bore, preferably by means of a tight fit;
• each heat pipe of the set of heat pipes a corresponding calibrated steel blind tube cast-in the plate body and extending from the rear face and terminating short of the front face, each heat pipe being fixed in thermally conductive manner within its corresponding blind tube, preferably by means of a tight fit.
• each heat pipe of a set of heat pipes is beneficially arranged with its condensation end portion at a distance of at least 2 mm, preferably a distance in the range of 2 to 15 mm, from an outer envelope of the associated coolant passage.
• the presently claimed staves are particularly adapted for industrial application in blast furnace cooling systems.
• the proposed staves are made of cast iron or steel and are installed at the level of the belly and/or of the bosh of the blast furnace.
• FIG.1 is a longitudinal cross-sectional view of a cooling stave according to a first embodiment
• FIG.2 is a lateral cross-sectional view according to line ll-ll of FIG.1 and FIG.4;
• FIG.3 is an enlarged view of region III in FIG.1 ;
• FIG.4 is a longitudinal cross-sectional view of a cooling stave according to a second embodiment
• FIG.5 is an enlarged view of region V in FIG.4;
• FIG.6 is a lateral cross-sectional view according to line VI-VI of FIG.4;
• FIG.7 is a longitudinal cross-sectional view of a cooling stave according to a third embodiment
• FIG.8 is an enlarged view of region VIII in FIG.7;
• FIG.9A is a lateral cross-sectional view according to line IX A-IX A of FIG.7, illustrating the third embodiment of a cooling stave;
• FIG.9B is a lateral cross-sectional view illustrating a fourth embodiment of a cooling stave.
• the stave 100 comprises a plate body 1 10 made of metallic material e.g. of a ferrous metal such as cast iron, typically spheroidal graphite cast iron (ductile C.I., DIN “GGG” type) or lamellar graphite cast iron (grey iron, DIN “GGL” - type).
• a ferrous metal such as cast iron, typically spheroidal graphite cast iron (ductile C.I., DIN “GGG” type) or lamellar graphite cast iron (grey iron, DIN “GGL” - type).
• the plate body 1 10 may also be made of another metal, e.g. of copper.
• the metallic plate body 1 10 has the general form of a parallelepiped, with a front face and an opposite rear face respectively indicated at 1 12 and 1 14.
• the front face 1 12 ("hot face") of the plate body 1 10 is advantageously provided with a series of alternating and regularly spaced parallel retaining ribs 1 16 and retaining grooves 1 18.
• the ribs 1 16 and grooves 1 18 are preferably dovetail shaped in lateral cross-section, as best seen in FIG.3. Accordingly, as shown in FIG.1 , the front face 1 12 is corrugated to increase the heat exchange surface and improve adherence of a refractory lining typically provided on the front face 1 12.
• the stave 1 10 is to be arranged on the inside of the shell of a metallurgical furnace, e.g. a blast furnace (not shown), with the front face 1 12 facing the interior reaction space of the furnace.
• the plate body 1 10 has dimensions in the following ranges: length: 500-5000mm, width: 200-2000mm, plate thickness: (smallest dimension, i.e. base wall thickness excluding ribs 1 16) 40-500mm.
• Reference number 120 identifies a generally straight, cylindrical coolant passage, e.g. in the form of an internal channel integrally formed during casting of the plate body 1 10 - as seen in FIG.1 - or, alternatively a channel machined by subsequent drilling.
• the plate body 1 10 includes several such coolant passages 120, which are normally parallel to one another.
• the coolant passages 120 extend inside and within the metallic plate body 1 10 in between the front face 1 12 and the rear face 1 14.
• the cross-section of each coolant passage 120 is normally circular, but a different, e.g. oval section is not excluded.
• the internal coolant passages are connected to connection pipe portions 122.
• connection pipe portions 122 of FIG.1 are welded transversely to the integrally formed channels that form the coolant passages 120, or alternatively, may be formed by bent portions of a coolant pipe, which is either inserted into a bore or cast-in into the plate body 1 10, and that forms the coolant passage (non-illustrated alternative).
• the connection pipe portions 122 respectively form an inlet and outlet for connecting the internal coolant passages 120 to the cooling circuit (not shown) of the blast furnace. While not necessarily being entirely straight and rectilinear, each coolant passage 120 normally has at least a rectilinear main portion, with a longitudinal axis A, as best seen in FIG.1 & FIG.2.
• a main set of heat pipes 130 is associated to each coolant passage 120.
• heat pipes have very high effective thermal conductance often several hundred times higher than that of copper, and can thus be considered as "thermal shorts".
• Suitable configurations for the heat pipes 130 are per se well known. Further details may be found e.g. in Reay, David and Peter Kew "Heat Pipes, Fifth Edition: Theory, Design and Applications” Butterworth-Heinemann publisher; 5 ed. (2006); ISBN 978-0750667548.
• Each heat pipe 130 has an evaporation end portion 132 (typically called “evaporator section”) and a condensation end portion 134 (typically called “condenser section”).
• the heat pipes 130 have an internal working agent (working fluid), as well as a container material, suitable for temperatures of >760°C. Suitable working agents are for example water or mercury.
• the heat pipes 130 normally have an internal wick arrangement, e.g. a sintered metal wick arrangement or internal grooves, for returning the working agent from the condensation end portion 134 to the evaporation end portion 132 by capillary action, irrespectively of the orientation of the heat pipes 130.
• heat pipes 130 may in principle have any, generally elongated geometry.
• each heat pipe 130 of the main set is arranged in the plate body 1 10 in a manner that improves heat transfer from the front face 1 12 ("hot face") to the rear face 1 14 ("cold face”) in general, and in particular to the associated internal coolant passage 120.
• each heat pipe 130 is arranged in layers at regular intervals along the longitudinal axis, in set preferably covering substantially the full length of the associated coolant passage 120.
• each heat pipe 130 is arranged to extend from the vicinity of the associated coolant passage 120 to the vicinity of the front face 1 12 without protruding into the retaining ribs 1 16.
• the heat pipes 130 of FIGS.1 -3 are embedded within the core parallelepiped-shaped part of the stave body 1 10 without passing into the ribs 1 16 so as to avoid exposure to higher mechanical stress to which the ribs 1 16 are typically subjected, among others due to temperature gradients and their refractory-supporting function.
• the heat pipes 130 are arranged to approximately cover the length of the associated coolant passage 120 within a central region excluding the uppermost and lowermost longitudinal extremities of the plate body 1 10, which are also subjected to considerable stress and wear.
• the heat pipes 130 are arranged in layers that correspond to the retaining ribs, with their longitudinal axes B approximately coinciding with the plane of symmetry of the corresponding retaining rib 1 16.
• the heat pipes 130 may also be arranged differently, e.g. without their longitudinal axes B located exactly mid-plane of the retaining ribs 1 16.
• the heat pipes 130 are preferably arranged with their longitudinal axis B oriented substantially perpendicular to the longitudinal axis A.
• each layer comprises a single heat pipe 130 having its axis B arranged to cross the axis A of the associated coolant passage.
• the number of heat pipes 130 associated per set to a coolant passage 120 approximately corresponds to the number of retaining ribs 1 16, subtracting 2-4 for one or two uppermost and lowermost retaining ribs 1 16, as illustrated in FIG.4.
• each main heat pipe 130 is embedded within the metallic plate body 1 10 with its condensation end portion 134 enclosed in a "cooled" portion of the metallic material of the plate body 1 10, which portion is contiguous to the associated coolant passage 120. Accordingly, in operation, heat transfer occurs from the condensation end portion 134 to the respective coolant passage through the "cooled" portion of plate material adjoining the coolant passage 120. In other words, the heat pipes 130 do not protrude into the coolant passages 120 nor out of the plate body 1 10.
• each heat pipe 130 is arranged so that the shortest distance between its condensation end portion 134 and the outer, e.g. cylindrical, envelope of the associated coolant passage 120 is greater than 2mm, preferably in the range of 2mm to 15mm, more preferably in the range of 5 to 10mm, in order to warrant practical safety at low thermal resistance.
• each heat pipe 130 is arranged with its evaporation end portion 132 enclosed in a "heated" portion of metallic material of the plate body 1 10 contiguous to the front face 1 12. Accordingly, heat transfer from the front face 1 12 to the evaporation end portion 132 will occur through the corresponding "heated portion" of plate material adjoining to the front face 1 12.
• the proposed configuration of heat pipes 130 considerably increases the overall heat conductivity in front-to-rear direction, from the "hot" front face 1 12 to the "cold" rear face 1 14.
• the coolant passages 120 thus have their longitudinal axis A, arranged closer to the rear face 1 14 than to the front face 1 12 i.e. at a ratio dr / df « 1 .
• the coolant passages 120 are configured such that the remaining thickness of material of the plate body 1 10 between the coolant passages 120 and the rear face 1 14 is minimized, being preferably in the range of 5 to 50mm. As a result, the risk of stress-induced failure of the coolant passages 120 causing a leakage is further reduced since the rear face 1 14 is least exposed to mechanical stress.
• FIG.1 illustrates a first group of parallel auxiliary heat pipes 140 which are embedded in the plate body 1 10 with a different orientation.
• each of the plurality of first auxiliary heat pipes 140 is arranged with its longitudinal axis C extending perpendicularly to the longitudinal axis A of the parallel coolant passages 120 and generally in parallel to the front face 1 12.
• the heat pipes 140 have their end portions 142, 144 located within plate material contiguous to the opposite lateral edges of the plate body 1 10. Accordingly, depending on the temperature distribution within the plate body 1 10, the end portions 142, 144 are operating either as condenser or evaporator section.
• the heat pipes 140 are normally equipped with an adiabatic central section 146, through which the end portions 142, 144 communicate.
• the heat pipes 140 are preferably arranged mid-plane of a corresponding retaining groove 1 18, a heat pipe 140 being provided for each retaining groove 1 18 except for the uppermost and lowermost grooves 1 18.
• the heat pipes 140 are arranged with their longitudinal axis C located approximately centrally on the shortest distance between the cylindrical envelope of the cooling passages 120 and the surface of the front face 1 12 at the bottom of corresponding groove 1 18.
• the first group of auxiliary heat pipes 140 increases thermal distribution along the width direction of the plate body 1 10 and thereby also distributes the thermal load more equally between the coolant passages 120.
• the auxiliary heat pipes 140 are regularly spaced, in alternation with the main heat pipes 130, as a group substantially covering the length of the coolant passages 120.
• a second group of auxiliary heat pipes may be provided in similar manner for improving thermal distribution along the length direction of said plate body and thus reducing wrapping of the stave.
• Such heat pipes can be embedded in the plate body 1 10 so as to extend in parallel to the longitudinal axes C of the coolant passages 120.
• FIGS.4-6 illustrate a second embodiment of a stave 200.
• FIGS.4-6 illustrate a second embodiment of a stave 200.
• the stave 200 of FIGS.4-6 with respect to the stave 100 of FIGS.1 -3 is detailed below.
• Other features, as identified by incremented hundreds digit, are identical or analogous to those described above.
• the evaporation end portion 232 of a main heat pipe 230 in the stave 200 is enclosed within the plate material forming the corresponding retaining rib 216.
• the thermal conductivity is further increased since the evaporation end portions 232 are located closer to the front- most plane of the corrugated front face 212.
• the heat pipes 230 may be provided with an intermediate adiabatic section. Safety distances between the condensation end portion 234 and the associated coolant passage 220 are preferably chosen similar to those set out above with respect to FIGS.1 -4.
• each heat pipe 230 is preferably arranged so that the shortest distance between its evaporation end portion 232 and the surface of the front face 212 at the tip of the corresponding rib 216 is in the range of 5 mm to 50 mm to minimize exposure to mechanical stress and wear so as to warrant sufficient lifetime of the heat pipes 230.
• the stave 200 of FIGS.4-6 is also equipped with auxiliary heat pipes 240 configured and arranged as detailed further above in relation to FIG.2. Furthermore, the axis B of each heat pipe 230 is also parallel to the front-to-rear direction, indicated by line D in FIG.6.
• FIGS.7-9A illustrate a third embodiment of a cooling stave, identified by reference 300. Only the differences with respect to the stave 100 of FIG.1 -3 and the stave 200 of FIGS.4-6 are detailed below. Other features are identical or analogous to those described above.
• each set associated to a given coolant passage 320 comprises a pair of heat pipes 330 in each layer, with layers corresponding to the retaining ribs 316 (except for one or two upper- and lowermost ribs). Accordingly, in the embodiment of FIGS.7A-9, the total number of heat pipes 330 is approximately equal to the number of coolant passages 320 multiplied by the number of ribs 316 multiplied by two, thus amounting e.g.
• FIGS.7-9A a stave 300 according to FIGS.7-9A has even higher thermal efficiency and is even less prone to premature failure.
• the two heat pipes 330 of each pair are arranged obliquely and mirror-symmetrically with respect to the transverse front-to-rear direction D. More specifically, their evaporation end portions 332 close to the front face 312 are spaced apart to a greater extent than their condensation end portions 334 adjacent the associated coolant passage 320.
• the longitudinal axes B of the heat pipes 330 in a pair are at an angle with respect to the transverse front-to-rear direction D.
• This arrangement allows doubling the number of "thermal shorts" from near the front face 312 to near the associated coolant passage 320, while at the same time warranting, along the width direction of the plate body 310, an approximately uniform distribution of the evaporation end portions 332 in the plate material contiguous to the front face 312. Similar to FIGS.1 -6, the condensation end portions 334 on the other hand, are enclosed in respective "cooled region" of material of the plate body 310.
• the "cooled region” is respectively contiguous to opposite sides of the main portion of the associated coolant passage 320, with - as above - heat transfer between the evaporation end portions 332 and the associated coolant passage 320 occurring through this protective "cooled region”.
• the main heat pipes 330 are longer than those used in FIGS.1 -6.
• the configuration of FIG.9A allows for a maximum heat pipe length while maintaining a uniform distribution of the evaporation end portions 332 along the width of the front face 312.
• the condensation end portions 334 are located closer to the rear face 314 of the plate body 310.
• the heat pipes 330 of each set go by closely and laterally of the associated coolant passage 320, on opposite sides of the passage main portion with respect to the front-to-rear direction D. Accordingly, a greater extent of the condensation end portions 334 is arranged in vicinity of the coolant passage 320 to improve cooling when compared to FIGS.1 -6.
• the heat pipes 330 are installed, e.g. by tight-fit, in a corresponding blind hole.
• the blind holes extend obliquely along axis B from the rear face 314 toward the front face 312 and terminate short of the front face 312, e.g. at distance in the range of 5mm to 50 mm.
• the terminal faces of the condensation end portions 334 are preferably flush or nearly flush with the rear face 314. While the lateral surface of the condensation end portions 334 is fully surrounded by plate material contiguous to the associated coolant passage 320, their front faces need not be (as enabled by larger exposure to cooling on the lateral surfaces).
• the heat pipes 330 of the stave 300 while also being arranged within the plate body 310 without protruding there from, are not completely embedded within the material of the plate body 310.
• FIG.9B illustrates a fourth embodiment of a stave, identified by reference 400.
• the stave 400 is substantially identical to that of FIGS.7-9A and differs only in that, for further simplified manufacture, the blind holes, in which the main heat pipes 430 are installed, are provided in the plate body 410 in parallel to the front- to-rear direction D. Accordingly, the heat pipes 430 are arranged within the plate body 410 with a longitudinal axis B that is both perpendicular to the axis A of the coolant passages 420 and perpendicular to the plane of the front face 412 / rear face 414.
• the main heat pipes 130, 230 of FIGS.1 -6, as well as the auxiliary heat pipes 140, 240 are completely embedded in the metallic material of the plate body 1 10, 210.
• a method suitable for complete embedding is:
• (c) for a cast plate body casting-in a calibrated blind tube, preferably made of steel, during the casting operation of the plate body 310, 310, which will have an end face flush with a surface of the plate body 310, 410 and have good thermal contact with the plate material due to carburization, followed after casting by insertion, e.g. by tight-fit or screwed connection, of the heat pipes 330, 430; 340; 440 and, if required, adding a protective filling material in a manner avoiding air inclusion in residual empty portions of the blind tube; or by
• the plate body 1 10, 210, 310, 410 may also be manufactured of a non-ferrous metal, in particular of copper.
• the plate body 1 10, 210, 310, 410 is usually either cast, e.g. according to US 6'470'958, or produced by machining a rolled slab.
• the heat pipes 130, 230; 140; 240 can also be installed by:
• the cooling staves 300, 400 of FIGS.7-9A&9B can be manufactured by any one of the methods (b), (c), (d) above.
• methods (a) or (e) can also be used to manufacture cooling staves 300, 400 according to FIGS.7-9A&9B or similar staves, in which the condensation end portions are embedded laterally of the coolant channels.
• FIGS.1 -3 242 end portions
• FIGS.7-9A 1 16 retaining ribs

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• Blast Furnaces (AREA)
• Furnace Housings, Linings, Walls, And Ceilings (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Furnace Details (AREA)

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• 2009
  • 2009-12-18 LU LU91633A patent/LU91633B1/en active
• 2010
  • 2010-12-15 KR KR1020127018869A patent/KR20120105532A/ko not_active Withdrawn
  • 2010-12-15 IN IN5092DEN2012 patent/IN2012DN05092A/en unknown
  • 2010-12-15 EP EP10798043A patent/EP2513344A1/en not_active Withdrawn
  • 2010-12-15 WO PCT/EP2010/069689 patent/WO2011073223A1/en not_active Ceased
  • 2010-12-15 RU RU2012130165/02A patent/RU2012130165A/ru not_active Application Discontinuation
  • 2010-12-15 CN CN2010800566404A patent/CN102712958A/zh active Pending
  • 2010-12-20 TW TW099144644A patent/TW201122113A/zh unknown

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