Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D19/00—Casting in, on, or around objects which form part of the product
  • B22D19/0072—Casting in, on, or around objects which form part of the product for making objects with integrated channels
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B7/00—Blast furnaces
  • C21B7/10—Cooling; Devices therefor
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
  • C21C5/28—Manufacture of steel in the converter
  • C21C5/42—Constructional features of converters
  • C21C5/46—Details or accessories
  • C21C5/4646—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
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/12—Casings; Linings; Walls; Roofs incorporating cooling arrangements
• • 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
  • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
  • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
  • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
  • F28D1/047—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
  • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
• • 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
  • F28D2021/0056—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for ovens or furnaces
  • F28D2021/0057—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for ovens or furnaces for melting materials

Definitions

• cast steel or (grey) cast iron cooling bodies can be used instead but are difficult to manufacture due to the high melting point of steel or iron, which requires high energy effort and the use of refractory molds that can withstand those high temperatures.
• the cooling conduits are usually also made of steel, cast steel or cast iron cannot easily be cast around said steel cooling conduits as said cooling conduits might melt without any additional refractory surface coating.
• the cooling body comprising a casing and a core material, said casing having an inner space filled with said core material, said core material at least partially embedding the at least one cooling conduit, wherein the material of the casing has a melting point of at least 100°C higher, preferably of at least 200°C higher, than the core material.
• the cooling unit according to this disclosure in comparison to welded cooling lines prevents cooling liquid leakage as a number of cooling conduits is used, whose outside surface is at least partially embedded into the core material.
• temperatures e.g., melting points, boiling points etc.
• temperatures are referred to as being under standard atmospheric conditions (i.e., at a pressure of 1 atm or 101 .3 kPa). If is used in connection to temperatures or thermal conductivity, a deviation of plus minus 5% is included.
• a cooling unit for a furnace as disclosed herein can be manufactured by providing a casing comprising a bottom and an inner space, wherein cooling conduits are provided within the inner space and wherein liquid core material is cast into the inner space to at least partly embed the cooling conduits, wherein the material of the casing has a melting point of at least 100°C higher, preferably of at least 200°C higher, than the core material.
• the liquid core material is cooled down to solidify and then represents the core material.
• a bottom of the casing is aligned horizontally during casting.
• the cooling conduits preferably also have a melting point at least 100°C higher, preferably at least 200°C higher, than the core material. Due to the lower melting point of the core material compared to the material of the casing and the cooling conduits, the core material can be cast into the casing and around the cooling conduits, at least partially embedding said cooling conduits without damaging the cooling conduits by the heat of the core material during the casting.
• a casing having an upper opening can be provided, wherein the liquid core material is cast into the inner space through the upper opening.
• the upper opening can be closed after casting the core material. This leads to a closed casing, which prevents leakage of the core material if said core material melts during operation.
• the provided casing comprises side walls with a number of apertures. The casing is immersed into a bath of liquid bulk core material - so that said liquid bulk core material fills the inner space. Afterwards the casing is removed from said bath of liquid bulk core material, such that excess liquid bulk core material flows out of the inner space through the apertures and the remaining liquid bulk core material represents the liquid core material.
• the core material After the core material is solidified, it extends to the edge of the apertures closest to the bottom of the casing and represents the core material.
• This process allows easy manufacturing as the bulk core material can be molten easily before casting into the inner space.
• the bottom of the casing is aligned horizontally during removal from said bath of liquid bulk core material and during solidification of the core material.
• the casing comprises cast steel, and/or (grey) cast iron and/or cast copper.
• the casing might also comprise steel plates, e.g., welded steel plates.
• Steel has a melting point of 1425°C to 1540°C (depending on the steel grade)
• grey cast iron has a melting point of -1150°C
• copper has a melting point of ⁇ 1083°C
• copper-tin alloy has a melting point of -1150°C to -1160°C
• copperzinc alloy (brass) has a melting point of 960°C to 1050°C (depending on the exact composition of the alloy).
• (Grey) cast iron has a thermal conductivity of -55 W/(m*K) which is higher than the thermal conductivity of steel (up to 50 W/(m*K). Also (grey) cast iron has the advantage of ensured leak proofness over welded steel plates and therefore prevents leakage of the core material during production and/or operation.
• Copper has a high thermal conductivity of -400 W/(m*K) and also allows modifications, e.g., application of attaching means, wherein screwing or milling is preferred over welding.
• the casing is closed which prevents leakage of the core material if said core material melts during operation.
• the casing can, for example, have the shape of a tub, e.g., having a bottom and side walls.
• the bottom and side walls can form a cuboid with an opening at the top, wherein a top surface can be omitted to form said opening.
• the casing has a side wall thickness and/or a bottom thickness of 10 to 30 mm, preferably 20 mm.
• the core material has a melting point from 200°C to 900°C, preferably from 400°C to 700°C.
• the core material has a thermal conductivity of at least 50 W/(m*K). It is preferred when the casing has a thermal conductivity of at least 40 W/(m*K) but heat resistant steel casings might also have a lower thermal conductivity, e.g., of about 20 W/(m*K). If the thermal conductivity of the core material is sufficiently high (e.g., at least 40 W/(m*K)), the thermal conductivity of the cooling body altogether is still sufficient, even when the thermal conductivity of the casing is relatively low. Of course, still high thermal conductivity of the casing and the core material is preferred.
• the core material comprises one or more of the following materials: zinc, tin, aluminum, copper.
• a copper alloy and/or aluminum alloy is used as core material.
• Zinc has a melting point of 420°C and a thermal conductivity of 1 10 W/(m*K)
• tin has a melting point of 232°C and thermal conductivity of 67 W/(m*K)
• aluminum has a melting point of 660°C and a thermal conductivity of 160 W/(m*K).
• the production cost of the cooling unit is kept low.
• the thermal expansion coefficients of the core material and the casing preferably differ by a maximum of 0.5 K -1 .
• Aluminum has a thermal expansion coefficient of 2.39 K -1 wherein stainless steel (e.g., steel type 1 .4841 usable for temperature of 1050°C to 1 100°C) has a thermal expansion coefficient of 1 .9 K -1 - therefore, e. g., the casing comprising stainless steel and the core material comprising aluminum (e.g., being an aluminum alloy) is a beneficial combination of materials, as corrosion is reduced, and the lifetime is extended.
• a casing comprising stainless steel and a core material comprising zinc and/or tin might be used. It might also be beneficial to use a casing comprising copper and a core material comprising aluminum.
• a casing comprising copper can also be combined with a core material comprising zinc (e.g., being a zinc alloy) and/or tin (e.g., being a tin alloy).
• a casing comprising (grey) cast steel e.g., steel type 1 .4848 or 2.4879
• a core material comprising aluminum e.g., steel type 1 .4848 or 2.4879
• a casing comprising (grey) cast steel can also be combined with a core material comprising zinc (e.g., being a zinc alloy) and/or tin (e.g., being a tin alloy).
• the boiling point (at standard atmospheric pressure of 1 atm or 101 .3 kPa) of the core material is above 900°C, preferably above 1650°C.
• Aluminum has a boiling temperature of 2470°C
• zinc has a boiling temperature of 907°C
• tin has a boiling temperature of 2602°C. Boiling tin leads to evaporation of poisonous gas. However, this is not an issue for the cooling unit described as the core material should not reach temperatures in the boiling temperature range of tin.
• the core material After mounting the cooling unit in a metallurgical furnace, during operation the core material might reach temperatures of up to 900°C on the hot side, wherein temperatures of the core material of about 40 to 60°C are reached in areas of the cooling conduits if the cooling function of the cooling unit works properly.
• core materials with higher boiling temperatures are preferred. Even when a failure of the cooling function of the cooling unit arises and the core material melts, said melting of the core material will absorb heat in the amount of the melting heat of the core material, which leads to an emergency cooling effect.
• the cooling unit for a metallurgical furnace can also comprise a cooling body and at least one cooling conduit leading through the cooling body, wherein a cooling liquid can be conducted via the at least one cooling conduit, wherein the cooling body comprises a casing and a core material, said casing having an inner space filled with said core material, said core material at least partially embedding the at least one cooling conduit, wherein the core material comprises zinc and/or tin and/or aluminum, wherein the material of the casing comprises steel and/or cast (grey) iron and/or copper.
• Connection ports at the ends of the number of cooling conduit can be provided for conducting cooling liquid, i.e., as input and/or output for said cooling liquid.
• a plurality of cooling conduits leading through the cooling body can be provided, which leads to better temperature distribution and dissipation. If the plurality of cooling conduits is constructed separately from each other, redundancy is provided which ensures the cooling system still is (partially) operational if a cooling conduit fails. Also, a plurality of cooling conduits can provide a large area covered by cooling conduits if said plurality of cooling conduits are meandered as the curve radius of cooling conduits should not be below a minimum curve radius.
• the number of cooling conduits has an outer surface. Preferably at least part of the outer surface of the number of cooling conduits is uncovered by the core material. Preferably at least part of an outer surface of the number of cooling conduits facing away from a bottom of the casing is uncovered by the core material.
• the part of the outside surface of the number of cooling conduits facing the bottom can be covered by the core material, wherein the part of the outside surface of the number of cooling conduits facing away from the bottom can be uncovered by the core material - at least in sections where the cooling conduits are parallel to the bottom.
• an outer surface of the number of cooling conduits is uncovered by the core material, in a region from 30% to 70% along the height of the cooling conduits, the height being measured along a direction normal to the bottom.
• an outer surface of the number of cooling conduits is uncovered by the core material, along at least 80% of the length of any respective number of cooling conduits in a region from 30% to 70% along the height of the cooling conduits, the height being measured along a direction normal to the bottom.
• the number of cooling conduits can be mainly covered by the core material, preferably at least in sections where the cooling conduits are parallel to the bottom. This can lead to better cooling compared to cooling conduits being partially or completely uncovered by the core material. Preferably connection ports at the end of the number of cooling conduits are uncovered for easier access to the cooling liquid.
• a cooling unit for a metallurgical furnace comprising a cooling body and at least one cooling conduit leading through the cooling body, wherein a cooling liquid can be conducted via the at least one cooling conduit, wherein the cooling body comprises a casing and a core material, said casing having an inner space filled with said core material, said core material at least partially embedding the at least one cooling conduit, wherein the core material comprises carbon, the core material being pasty.
• the melting point of the core material can also be less than 100°C higher, or equal or lower compared to the melting point of the material of the casing, in particular if the core material is pasty.
• FIG. 1 to 4 show exemplary, schematic, and non-limiting advantageous embodiments of the invention wherein
• Fig. 1 shows a casing 20 for a cooling body 2 for a cooling unit 1 .
• the casing 20 has an inner space I, defined by a bottom B and side walls S and preferably comprises cast steel and/or cast copper and/or cast iron.
• the casing 20 might also comprise, e.g., welded, steel plates or copper plates.
• the casing 20 depicted by way of example has a rectangular bottom B and perpendicular side walls S, while having an upper opening O opposite of the bottom B. Of course, other shapes of the bottom B and/or the side walls S and/or the upper opening O are possible.
• the casing 20 by way of example also has mounting means M.
• the mounting means M can be used for furnace roof mounting and/or furnace wall mounting.
• the side walls S of the casing 20 by way of example comprise a number of apertures A, preferably being distanced from the bottom B of the casing 20.
• a cooling unit 1 for a furnace For manufacturing a cooling unit 1 for a furnace, at least one cooling conduit 3 is provided within the inner space I, the at least one cooling conduit 3 configured to conduct a cooling liquid, e.g., water.
• Fig. 2 shows the casing 20 from Fig. 1 wherein two meandered and intertwined cooling conduits 3 are provided.
• the at least one cooling conduit 3 has an outer surface 31 and connection ports 30 at the end for conducting the cooling liquid, i.e., as input and/or output for said cooling liquid.
• an optional fastening unit 4 is provided, to keep the cooling conduits 3 in place during the casting process and during operation, wherein in Fig. 2 the fastening unit 4 by way of example is embodied as rods mounted across the cooling conduits 3 and connected to the side walls S.
• the fastening units 4 might also be embodied as clamps.
• the clamps can be attached, e.g., welded, to the bottom B of the casing 20.
• liquid core material having a melting point at least 100°C lower, preferably 200°C lower than the material of the casing, is cast into the inner space surrounding the cooling conduits 3, e.g., through the upper opening O and solidifies to form the core material 21 .
• the cooling body 2 therefore comprises the casing 20 and the core material 21 , wherein the cooling unit 1 comprises the cooling body 2 and the cooling conduits 3 leading through the core material 21 of said cooling body 2.
• the core material 21 can be chosen such that the boiling point of the core material 21 is above 900°C, preferably above 1650°C.
• the core material 21 is chosen such that its melting point is between 200°C and 900°C, preferably between 400°C and 700°C.
• the core material 21 comprises one or more of the following materials: zinc, tin, aluminum.
• the casing 20 can also be immersed into a bath of liquid bulk core material and then removed from the bath of liquid bulk core material, such that excess liquid bulk core material flows out of the inner space I through the apertures A and the remaining liquid bulk core material represents liquid core material, after solidifying representing the core material 21 .
• the core material 21 fills the inner space I up to the edge of said number of apertures A closest to the bottom B of the casing 20.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Furnace Housings, Linings, Walls, And Ceilings (AREA)

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• 2023
  • 2023-10-04 EP EP23783437.9A patent/EP4598699A1/de active Pending
  • 2023-10-04 WO PCT/EP2023/077493 patent/WO2024074575A1/en not_active Ceased

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