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(11) | EP 0 982 555 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Slab transport roller |
| (57) A slab transport roller comprises a tubular body for passing cooling water therethrough,
tires (20) fixedly fitted around the tubular body at a plurality of portions of the
body spaced apart axially thereof, and a heat-insulating sleeve (3) provided around
the tubular body except at the tire fixed portions thereof. The sleeve comprises a
tubular case including an inner cylindrical wall (36) and an outer cylindrical wall
(37) arranged concentrically so as to form an annular space therebetween, and a pair
of side walls (38) closing the annular space at opposite ends of the cylindrical walls,
and further comprises a heat-insulating material (34) accommodated in the annular
space of the tubular case. |
FIELD OF THE INVENTION
[0001] The present invention relates to thin slab transport rollers, for example, for use in the heating furnace of a line for continuously casting thin slabs, and to improvements in the process for assembling the roller.
BACKGROUND OF THE INVENTION
[0002] In iron mills, a heating furnace of the tunnel type is disposed between an apparatus for continuously casting thin slabs and rolling equipment, and a multiplicity of transport rollers are arranged within the furnace.
[0003] FIGS. 12 and 13 show such a slab transport roller 1. FIG. 13 is a view in section taken along the line XIII-XIII in FIG. 12 and showing the roller as it is seen in the direction of the arrows. As illustrated, the roller 1 comprises a tubular body 10, and a plurality of tires 20 arranged axially of the tubular body 10 and fixedly fitted therearound. The roller is connected to and rotatable by a rotating mechanism (not shown). A cast slab 6 is supported by the peripheries of the tires 20 and transported inside the furnace. Since the furnace has a high-temperature atmosphere of at least about 1000°C inside thereof, cooling water is passed through the tubular body 10 for preventing the deflection or deformation of the body 10 at high temperatures, and the tubular body 10 is covered with a heat-insulating material 34 over its peripheral surface except at the tire fixed portions thereof.
[0004] The tires 20 are fixed to the tubular body 10 as by welding. The covering of heat-insulating material 34 is prepared by welding a multiplicity of studs 33 to the peripheral surface of the tubular body 10, coating the surface with a monolithic heat-insulating material, such as a castable, to a predetermined thickness and drying the coating.
[0005] In the case of the transport roller described, the heat-insulating material 34 separates off or dislodges owing to a fall of slab scales, vibration or impact, failing to effectively cover or protect the tubular body 10 and consequently accelerating deformation of the tubular body 10, wear thereon due to oxidation, or the like to shorten the service life of the transport roller.
[0006] FIG. 14 shows another transport roller wherein the heat-insulating material 34 is enclosed with a protective member 60 made from a heat-insulating steel plate to preclude the above drawback. The protective member 60 is made by providing a hollow cylindrical member 61 around the heat-insulating material 34, covering opposite end faces of the material 34 with respective annular side plates 63, 63, and welding each end edge of the cylindrical member 61 to the side plate 63.
[0007] However, much time and labor are required for attaching many studs 33 to the tubular body 10 by welding. Further since the protective member 60 is assembled after the heat-insulating material 34 is applied and dried, the application and drying of the heat-insulating material 34 necessitate a long period of waiting time. The transport roller is therefore very inefficient to assemble.
[0008] The cylindrical member 61 of the protective member 60 is smaller than the tire 20 in outside diameter, so that the protective member 60 can not be passed over the tire 20. This gives rise to the need to alternately perform the work of fixedly fitting the tire 20 around the tubular body 10 and the work of installing the heat-insulating material 34 and assembling the protective member 60. Nevertheless, if much labor and time are required to install the heat- insulating material 34 and to assemble the protective member 60 as stated above, the transport roller 1 is extremely inefficient to make and necessitates a greatly increased production cost.
[0009] An object of the present invention is to overcome the foregoing problems involved in producing slab transport rollers by providing an improved protective member for enclosing the heat-insulating material.
SUMMARY OF THE INVENTION
[0010] To fulfill the above object, the present invention provides a slab transport roller which comprises a tubular body having tires fixedly fitted therearound, and a heat-insulating sleeve provided around the tubular body except at the tire fixed portions thereof, the heat-insulating sleeve comprising a tubular case and a heat-insulating material, the tubular case including an inner cylindrical wall and an outer cylindrical wall arranged concentrically so as to form an annular space therebetween, and a pair of side walls closing the annular space at opposite ends of the cylindrical walls, the heat-insulating material being accommodated in the annular space of the tubular case.
[0011] The present invention also provides a process for assembling the slab transport roller described which process has the steps of fixedly fitting the tires around the tubular body, fitting the heat-insulating sleeve around the tubular body with the heat-insulating material accommodated in the annular space of the tubular case, and fixing the tires to or lockingly engaging the tires with the tubular case of the heat-insulating sleeve.
[0012] According to the invention, the heat-insulating sleeve is produced preferably by a process comprising the steps of forming a foam replica of the tubular case with the heat-insulating material accommodated in the annular space, preparing a mold for lost-foam casting by enclosing the foam replica in molding sand within a casting container and removing air from the sand by suction to compact the sand, and placing a molten heat-resistant alloy for forming the tubular case into the casting container to replace the foam replica by the heat-resistant alloy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013]
FIG. 1 is a front view in section partly broken away and showing a transport roller embodying the invention;
FIG. 2 is a view in section taken along the line II-II in FIG. 1;
FIG. 3 is a perspective diagram showing an embodiment of tubular case of the invention;
FIG. 4 is a perspective diagram showing a foam replica for preparing the tubular case of the invention as a cast body with a heat-insulating material accommodated therein;
FIG. 5 is a sectional view showing a lost-foam casting container with a foam replica and molding sand accommodated therein;
FIG. 6 is a view in axial section of a heat-insulating sleeve and a tire to show a mode of engagement therebetween according to the invention;
FIG. 7 is a view in axial section the heat-insulating sleeve and the tire to show another mode of engagement therebetween according to the invention;
FIG. 8 is a side elevation showing another embodiment of tubular case of the invention;
FIG. 9 is a view in section taken along the line IX-IX in FIG. 8;
FIG. 10 is a side elevation of an embodiment of tire;
FIG. 11 is a view in section taken along the line XI-XI in FIG. 10 and showing the tire;
FIG. 12 is a front view partly broken away and showing a conventional transport roller;
FIG. 13 is a view in section taken along the line XIII-XIII in FIG. 12; and
FIG. 14 is a view in axial section showing another example of conventional transport roller.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The present invention will be described below in detail with reference to the embodiments shown in the drawings.
[0015] FIGS. 1 and 2 show an embodiment of transport roller of the present invention. FIG. 2 is a view in section taken along the line II-II in FIG. 1.
[0016] Heat-insulating sleeves 3 fitted around a tubular body 10 each comprise a tubular case 30 and a heat- insulating material 34. As illustrated, the tubular case 30 comprises an inner cylindrical wall 36 and an outer cylindrical wall 37 which are arranged concentrically and opposed to each other so as to form an annular space therebetween, and a pair of annular side walls 38, 38 closing the annular space at opposite ends of the cylindrical walls. SUS 310S steel or like heat-resistant material is suitable for making the tubular case 30 as a material capable of withstanding the interior high-temperature atmosphere of the heating furnace.
[0017] The annular space formed in the tubular case 30 is filled with the heat-insulating material 34. Examples of suitable materials for use as the heat-insulating material 34 include various monolithic materials, such as castables, which are conventionally used, alumina, zinc oxide and like other ceramic fibers.
[0018] According to the invention, the inner cylindrical wall 36 of the tubular case 30 can be provided on its outer peripheral surface with studs 33 (e.g., V-shaped or Y-shaped studs) for supporting the heat-insulating material 34 when so desired as in the prior art. The studs 33 may be provided on the inner peripheral surface of the outer cylindrical wall 37 of the tubular case 30.
[0019] The heat-insulating sleeve 3 of the invention is produced by the process to be described below in detail.
[0020] According to a first preferred embodiment, a member for the inner cylindrical wall 36 of small diameter, a member for the outer cylindrical wall 37 of large diameter and members for the pair of annular side walls 38, 38 are prepared for making the tubular case 30. The heat-insulating sleeve 3 is fabricated by arranging the member for the wall 36 and the member for the wall 37 concentrically as opposed to each other to form an annular space, filling the heat-insulating material 34 into the space, and welding the members for the pair of side walls 38, 38 to the members for the walls 36, 37 at opposite ends of the latter members.
[0021] If holes 72 for filling the heat-insulating material 34 therethrough are formed in the annular side walls 38, 38, with corresponding caps 73 prepared for the holes 72 as seen in FIG. 3, the heat-insulating material 34 can be filled into the annular space of the tubular case 30 through the holes 72 even after the case 30 is formed by closing the opposite open ends of the inner and outer cylindrical walls 36, 37 with the annular side walls 38, 38. In this case, the holes 72 are closed with the caps 73 after the material 34 has been completely filled in.
[0022] According to a second preferred embodiment, the heat-insulating sleeve 3 having the heat-insulating material 34 accommodated in the annular space of the tubular case 30 is produced by the lost-foam process. This process will be described with reference to FIGS. 4 and 5.
[0023] FIG. 4 shows the components of a foam replica 40 to be made of a foam such as expanded polystyrene.
[0024] As illustrated, an inner cylindrical wall member 46 and an outer cylindrical wall member 47 both made of the foam are arranged concentrically to form an annular space between the two members. After the heat-insulating material 34 is filled into the annular space formed, opposite open ends of the wall members 46, 47 are closed with annular side wall members 48, 48 similarly made of the foam by joining the members 48 to the members 46, 47 with an adhesive. In this way, the foam replica 40 is formed with the heat-insulating material 34 contained in the annular space.
[0025] When studs 33 are to be provided, for example, on the inner cylindrical wall 36 as previously described with reference to the embodiment of transport roller, rod members 43 corresponding to the studs in shape are prepared from the foam and attached to suitable portions of outer periphery of the inner cylinder wall member 46 with adhesive.
[0026] Next, the foam replica 40 thus formed is placed into a casting container 50 and enclosed in molding sand 51 as shown in FIG. 5. With the upper portion of the container 50 covered with a vinyl sheet (not shown), a suction nozzle is inserted into the container 50, and air is removed from the sand 51 by suction using suction means such as a vacuum pump, whereby the sand 51 is compacted to shape a mold for lost-foam casting. A melt of heat-resistant alloy for forming the tubular case 10 is poured into the container in this state, whereupon the foam portion of the replica 40 disappears under the action of heat of the molten metal, and the molten metal fills the lost portion and solidifies, whereby a cast body is obtained with the heat-insulating material 34 enclosed therein. In this way, the heat-insulating sleeve 3 is produced with the heat-insulating material 34 accommodated in the annular space of the tubular case 30 at the same time.
[0027] The lost-foam process for casting can be practiced in the usual manner without necessitating special conditions or additional limitations, with the exception of filling the heat-insulating material 34 into the interior of the foam replica 40, efficiently affording a composite body with high reliability with respect to the shape and construction.
[0028] As already described above, the transport roller 1 of the invention comprises a tubular body 10, tires 20 fixedly fitted around the tubular body at a plurality of portions of the body spaced apart axially thereof, and heat-insulating sleeves 3 provided around the tubular body except at the tire fixed portions thereof and each having a heat-insulating material 34 accommodated in an annular space of a tubular case 30. The transport roller 1 of the invention is assembled by the process to be described below.
[0029] First, a tire 20 is fixedly fitted around the tubular body 10 at the approximate midportion of its length. The tire 20 comprises, for example, the combination of a tire body 21 and support frames 22 for supporting the tire body. For the prevention of idle rotation, the support frames 22 are secured to the tubular body 10 as by welding.
[0030] Heat-insulating sleeves 3, 3 of the invention each having the heat-insulating material 34 contained in the annular space of the tubular case 30 are then fitted respectively to opposite sides of the tire 20.
[0031] Next tires 20, 20 are fitted to the outer sides of the respective sleeves 3, 3 and secured to the tubular body 10. The transport roller is assembled by repeating this procedure axially outwardly of the tubular body 10 in succession.
[0032] In fixedly fitting the tires 20 around the tubular body 10, one tire 20 may be mounted first at one end of the tubular body 10, or the sleeve 30 may be mounted first on the tubular body.
[0033] To render the heat-insulating sleeve 3 rotatable with the tubular body 10, it is necessary to secure the sleeve 3 directly to the surface of the tubular body 10 as by welding, or to fix the sleeve 3 to the side portion of the tire 20 secured to the tubular body 10, or to engage the sleeve 3 with the tire 20 secured to the body 10.
[0034] The heat-insulating sleeve 30 can be lockingly engaged with the tire 20 according to one of the following embodiments.
[0035] For example as shown in FIG. 6, a key member 83 is provided on the tire body 21 of the tire 20, and a key groove 85 corresponding to the key member is formed in the side wall 38 of the tubular case 30 of the sleeve 3 so as to engage the sleeve 30 with the tire 20 by rotating the tubular member 10. Alternatively, the key member 83 may be formed on the side wall 38 of the sleeve tubular case 30, with the key groove 85 formed in a side portion of body 21 of the tire 20 as shown in FIG. 7.
[0036] Further alternatively as shown in FIG. 8, projections 87 are provided on the outer side surface of side wall 38 of the sleeve tubular case 30 at respective portions spaced apart circumferentially thereof (at three portions spaced apart by an angle of 120 degrees about the center in the illustrated embodiment), and bores 89 corresponding to the projections are formed in the support frames 22 of the tire 20 as shown in FIGS. 10 and 11. The sleeve 3 can be engaged with the tire 20 by inserting the projections 87 into the respective bores 89 as seen in FIG. 9.
[0037] As is the case with the key member and the key groove described, the projections 87 may be formed on side portions of the tire 20 to fit into bores 89 formed in the side wall 38 of the sleeve tubular case 30.
[0038] In the case where the key member 83 or each projection 87 is to be provided on the side wall 38 of the tubular case 30 by the lost-foam process, a member corresponding to the key member 83 or projection 87 in shape is prepared from a foam and attached with adhesive to a suitable portion of the side wall member 48 of the foam replica 40 with adhesive before preparing the mold.
[0039] With the embodiment wherein the heat-insulating sleeve 3 is in engagement with the tire 20, the sleeve 3 is free to thermally expand when the roller is exposed to the high-temperature atmosphere within the furnace, imposing no stress on the tire 20 or tubular body 10 and causing no deformation.
[0040] The heat-insulating material 34 is accommodated in the annular space of the tubular case 30 of the sleeve 3 in advance, so that the invention, unlike the prior art, does not require a long period of waiting time for the application and drying of the heat-insulating material in assembling the transport roller, while the sleeve 3 can be fitted around the tubular body 10 with extreme ease within a short period of time.
[0041] The transport roller of the invention includes heat-insulating sleeves each having the heat-insulating material accommodated in the annular space of tubular case. The tires and heat-insulating sleeves can therefore be fixedly fitted around the tubular body alternately easily and efficiently. This is very useful for achieving an improved efficiency and a cost reduction in producing the transport roller.
1. A slab transport roller which comprises a tubular body for passing cooling water therethrough,
tires fixedly fitted around the tubular body at a plurality of portions of the body
spaced apart axially thereof, and a heat-insulating material provided around the tubular
body except at the tire fixed portions thereof, the slab transport roller being characterized
in that:
a heat-insulating sleeve is fitted around the tubular body over a region thereof to be covered with the heat-insulating material, the heat-insulating sleeve comprising:
a tubular case including an inner cylindrical wall and an outer cylindrical wall arranged concentrically so as to form an annular space therebetween, and a pair of side walls closing the annular space at opposite ends of the cylindrical walls; and
the heat-insulating material as accommodated in the annular space of the tubular case.
2. The slab transport roller according to claim 1 wherein studs are provided on an outer
peripheral surface of the inner cylindrical wall and/or an inner peripheral surface
of the outer cylindrical wall.
3. The slab transport roller according to claim 1 wherein the tubular case of the heat-insulating
sleeve is lockingly engageable with the tires.
4. The slab transport roller according to claim 3 wherein the sleeve tubular case has
a projection formed on each side wall thereof, and the tire is formed in a side portion
thereof with a bore permitting the projection to fit in.
5. The slab transport roller according to claim 3 wherein each of the tires has a projection
formed on a side portion thereof, and the sleeve tubular case is formed in the side
wall thereof with a bore permitting the projection to fit in.
6. The slab transport roller according to claim 3 wherein the sleeve tubular case has
a key member formed on each side wall thereof, and the tire is formed in a side portion
thereof with a key groove permitting the key member to lockingly engage in.
7. The slab transport roller according to claim 3 wherein each of the tires has a key
member formed on a side portion thereof, and the sleeve tubular case is formed in
the side wall thereof with a key groove permitting the key member to lockingly engage
in.
8. A process for assembling a slab transport roller according to claim 1 which process
is characterized by the steps of:
fixedly fitting the tires around the tubular body;
fitting the heat-insulating sleeve around the tubular body, with the heat-insulating material accommodated in the annular space of the tubular case; and
fixing the tires to or lockingly engaging the tires with the tubular case of the heat-insulating sleeve.
9. A process for producing a heat-insulating sleeve for use in a slab transport roller
comprising a tubular body and tires fixedly fitted around the tubular body at a plurality
of portions thereof spaced apart axially of the body to cover the tubular body between
the tires, the heat-insulating sleeve comprising a tubular case and a heat-insulating
material, the tubular case including an inner cylindrical wall and an outer cylindrical
wall arranged concentrically so as to form an annular space therebetween, and a pair
of side walls closing the annular space at opposite ends of the cylindrical walls,
the heat-insulating material being accommodated in the annular space of the tubular
case, the process having the steps of:
forming a foam replica of the tubular case with the heat-insulating material accommodated in the annular space;
preparing a mold for lost-foam casting by enclosing the foam replica in molding sand within a casting container and removing air from the sand by suction to compact the sand; and
placing a molten heat-resistant alloy for forming the tubular case into the casting container to replace the foam replica by the heat-resistant alloy.