The invention relates to a lateral seal of a casting gap according to the preamble of claim 1 formed between two casting rollers of a strip casting machine.
A lateral seal of this type is disclosed in WO 2004/033130, FIGS. 7 to 9. It comprises a wetted first part made from a fireproof material and a second part made from a high-temperature-resistant material that is allocated to the front sides of the casting rollers. The second part has a kind of “snout shape” with two legs which extend along the casting roller front sides and join together at the bottom above a so-called kissing point to form a common area, between which legs the first part protrudes from above. The first part is made from a fireproof material, the second from a high-temperature-resistant alloy, a grey cast iron or a high-strength steel. The two parts are provided with a coating.
The underlying objective of the present invention is to improve a lateral seal of the aforementioned type not only with respect to its wearing resistant and durability but also with respect to heat loss in order to prevent unwanted hardening in this area.
This objective is achieved according to the invention by means of a lateral seal with the features of claim 1.
Further preferred embodiments of the lateral seal according to the invention are the subject matter of the dependent claims.
Owing the fact that an insulating layer separating the two parts from one another is inserted between the first and second part, heat loss is largely prevented or minimised at the lateral seals, so that even when using a protected metal plate in the wetted area no hardening occurs. The wetted part 12 can be kept very hot and can be preheated to a very high temperature (900-1,300° C.).
The invention is explained in more detail in the following by way of the drawing. The Figures show:
FIG. 1 a first embodiment of a lateral seal according to the invention in front view;
FIG. 2 a section along line II-II of FIG. 1;
FIG. 3 in the left half a section along line IIIA-IIIA and in the right half a section along line IIIB-IIIB of FIG. 2;
FIG. 4 a section along line IV-IV of FIG. 1;
FIG. 5 a section along line V-V of FIG. 1;
FIG. 6 a second embodiment of a lateral seal according to the invention in front view;
FIG. 7 a section along line VII-VII of FIG. 6;
FIG. 8 in the left half a section along line VIIIA-VIIIA and in the right half a section along line VIIIB-VIIIB in FIG. 7;
FIG. 9 a section along line IX-IX of FIG. 6;
FIG. 10 a section along line X-X of FIG. 6;
FIG. 11 a third embodiment of a lateral seal according to the invention in front view;
FIG. 12 a section along line XII-XII of FIG. 11;
FIG. 13 in the left half a section along line XIIIA-XIIIA and in the right half a section along line XIIIB-XIIIB of FIG. 12;
FIG. 14 a section along line XIV-XIV in FIG. 11;
FIG. 15 a fourth embodiment of a lateral seal according to the invention in vertical cross section, corresponding to FIG. 12;
FIG. 16 the lateral seal according to FIG. 15 in horizontal cross section, corresponding to FIG. 14;
FIG. 17 a fifth embodiment of a lateral seal according to the invention in vertical cross section;
FIG. 18 the lateral seal according to FIG. 17 in horizontal cross section;
FIG. 19 a sixth embodiment of a lateral seal according to the invention in vertical cross section; and
FIG. 20 the lateral seal according to FIG. 19 in horizontal cross section.
FIGS. 1 to 5 show a first embodiment of a lateral seal 10 for a roller-strip casting machine which is provided for laterally sealing a casting gap formed between two casting rollers. Two lateral seals 10 (also called narrow side parts) arranged on both front sides of the casting rollers limit the length of the casting gap. The casting rollers are shown in FIGS. 3, 4 and 5 and denoted by 1, 2.
The lateral seal 10 is accommodated in a holding frame 11, which is in active connection with an adjusting device not shown in the drawing. The holding frame 11 can be adjusted together with the lateral seal 10 in longitudinal direction of the casting rollers 1, 2, by means of which the lateral seal 10 can be positioned with its sealing side 10′ on front sides of the casting rollers 1, 2.
The lateral seal 10 comprises a so-called wetted first part 12, which in the embodiment variant according to FIGS. 1 to 5 is made from a fireproof material, and a second part 13 allocated to the front side of the casting rollers 1, 2, which is made of a preferably high-temperature-resistant metal. Both parts 12, 13 are preferably provided with a suitable coating. The second part 13 has a kind of “snout shape” with two legs 13s which extend along the casting roller front sides and join together at the bottom above a so-called kissing point to form a common middle area 13m (cf. in particular the right half of FIG. 3). The first part 12 projects from above between the two legs 13s of the second part 13 and is centred by the latter, and overlaps the casting roller front sides radially by 1 to 3 mm thus covering their edge area. The first part 12 is held in a surrounding sheet 15 (FIG. 2) attached onto the second part 13 and forming a kind of cassette with the latter, whereby it is positioned in the depression relative to the surrounding sheet 15 on the rear side facing away from the sealing side 10′ by means of spacing pieces 16 and is separated from the surrounding sheet by an insulating plate 17 (FIG. 2).
According to the invention the first part 12 is provided not only to the rear but along its entire contour with insulation 18, 19 (FIGS. 2, 3, and 4), which also separates the two parts 12, 13 from one another and which for protection, to avoid compression, stands back slightly in the depression from the sealing side 10′ of the parts 12, 13, and in addition a nose 13′ centring the insulation and projecting from part 13 is provided.
The cassette-like lateral seal 10 is inserted from the front into the holding frame, so that the surrounding sheet 15 and the snout-shaped second part 13 lie at the rear on a base surface of the holding frame 11 provided with cooling channels 20, 21 for a cooling medium, preferably cooling water. The cooling channels 20, 21 are connected on the one hand to a cooling water inlet 26 (FIGS. 2, 3, and 5) and on the other hand via additional, upper and lateral holding frame-cooling channels 22, 23 to a cooling water outlet 25 (FIGS. 2 and 3). The snout-like second part 13 is thus cooled directly from the rear.
The snout-shaped second part 13 is provided according to the invention with a number of outlet openings 30 distributed preferably evenly along the edges of the casting rollers and directed opposite the front sides of the casting rollers 1, 2 which are connected via distribution channels 31, 32 to a gas or lubricant source 35 (FIGS. 1, 3 and 5). Through the outlet openings 30 inert gas, crude oil or other suitable materials such as grease or coatings containing graphite can be distributed over the sealing parts along the front sides or edges of the casting rollers and form a very thin bearing layer (gap 0.01-0.03 mm).
As already mentioned, the snout-shaped second part 13 (i.e. the front side of the sealing parts) is covered with a layer which can cushion the change in length of the casting rollers during casting. Instead of this a heat and abrasion-resistant film with suitably stamped holes for the outlet openings 30 can also be attached onto the second part 13.
It is known that lateral seals, particularly when they contain fireproof sealing plates or sealing plate parts as in the first part 12 according to FIGS. 1 to 5, need to be preheated prior to casting. The lateral seal 10 according to the invention, with insulation 18 inserted between the first and second part 12, 13 and separating the two parts 12, 13 from one another, has the advantage that, unlike in previous solutions, the majority of the heat is derived through the front sides of the casting rollers.
By means of the direct bearing of the snout-shaped second part 13 on the cooled holding frame 11 this area remains in terms of temperature substantially below the high temperature of 800-1,300° C. required for the first wetted part 12.
The outlet openings 30 in the snout-shaped second part 13 are produced as small bores in order to permit hydrodynamic bearing. They can also be in the form of slots extending in circumferential direction of the casting rollers.
In FIGS. 6 to 10 a second embodiment of a lateral seal 10a is shown. Identical parts of this lateral seal 10a are denoted by the same reference numbers as in FIGS. 1 to 5. The lateral seal 10a comprises a wetted first part 12a and a snout-shaped second part 13a, which bear at the rear on a metal plate 37, wherein the plate 37 is positioned in the depression by spacing pieces 16a opposite a surrounding sheet 15 and is separated from the latter by an insulation plate 15. The lateral seal 10a is thus again designed in the form of a cassette which can be inserted from the front into the holding frame 11. (In fact, here too the snout-shaped second part made from a high-temperature-resistant metal could also advantageously bear directly against the cooled holding frame 11.) The wetted first part 12a is made in this variant from a high-temperature-resistant metal and is provided with insulation 18, 19 along its entire contour, so that the two parts 12a, 13a are centred relative to one another but separate from one another.
The snout-shaped second part 13a also comprises further outlet openings 40a (FIGS. 6 and 10) in the central area 13m in addition to the outlet openings 30 distributed along the casting roller edges. However, the metal first part 12a, which is preferably, coated with a ceramic layer, is also provided with a number of outlet openings 40 distributed over its surface, which together with the additional outlet openings 40a in the middle area 13m of the second part are connected to a separate gas or lubricant source 45 (inert gas, oil, coating etc.), by means of a central, vertical connecting channel 44 and horizontal distribution channels 43 branching off from the latter, which are formed in the rear plate 37. In this way a film can be formed on the sealing side 10a′.
The outlet openings 40 provided in the wetted first part 12a can vary in size over height in order to allow for ferrostatic differences in pressure.
In FIGS. 11 to 14 a further embodiment of a lateral seal 10b is shown, which comprises a snout-shaped part 13b made from a high-temperature-resistant metal, which is provided in turn with outlet openings 30 distributed along the roller edges and together with the wetted first part 12b bears on a rear metal plate 37b. The wetted part 12b is formed by a plate 50 made of a high-temperature-resistant metal which has a number of openings 51 distributed over the entire surface that are filled with a fireproof or fibre-like material 52. In this way it is taken into consideration that the expansion coefficients are selected to that no gaps can occur. This embodiment makes it possible to reduce the proportion of metal in the wetted first part 12b to 25-50%.
Around the openings 51 small bores are made in the metal plate 50 which form outlet openings 54 for a medium such as gas, oil, coatings etc. and are charged independently of the outlet openings 30 of the snout-shaped parts 13b, for which a separate source 45 and connection channels or chambers 55, 56 made in the rear plate 37b are provided. In this way the wetted first part 12b can be provided with an insulating protective film.
A lateral seal 10c shown in FIGS. 15 and 16 corresponds essentially to the aforementioned lateral seal 10b. The first part 12c comprises the metal plate 50 with larger openings 51, unlike the variant according to FIGS. 11 to 14, however the openings 51 alone are not filled but the metal plate 50 is filled with a fireproof material projecting over the seal side, so that a fireproof plate 59 is formed with cylindrical projections 60 protruding into the openings 51. In this way the metal plate 50 is further protected in terms of temperature and the removal of heat is reduced. The seal side is also coated in this case. The fireproof material is held together by the metal plate 50, i.e. the metal plate opposes the development of cracks in the fireproof material.
In FIGS. 17 and 18 a lateral seal 10d is shown which differs from the one shown in FIGS. 11 to 14 in that the first wetted part 12d (or its metal plate 50d, the openings 51d of which are filled with a fireproof material 52d) is provided with a central, projecting nose 63 protruding between the casting rollers 1, 2, wherein the depth of said nose 63 decreases from top to bottom. By means of this nose 63 the hot molten metal supplied from the casting pipe is forced into the edge area of the casting rollers 1, 2, in order to eliminate parasitic hardened areas.
A lateral seal 10e shown in FIGS. 19 and 20 corresponds essentially to the design according to FIGS. 15 and 16, however the first wetted part 12e has a nose 63e protruding between the casting rollers 1, 2, which corresponds in shape to the one according to FIGS. 17 and 18 but is allocated to the fireproof plate 59e.
All of the embodiment variants described above are characterised by having the snout-shaped part 13 in which the wetted part 12 is held in a centred position by an interposed insulation 18. The wetted part 12 can be kept very hot and preheated to a very high temperature (900-1,300° C.).
Owing to the charging of gas or lubricant in the sealing area and due to the abrasion-resistant seating of the snout-shaped part wear is reduced considerably or largely prevented which considerably increases the durability of the lateral seals. The structure of the cassette of the lateral seals according to the invention permits various advantageous, exchangeable combinations of fireproof material and metal in the wetted area, with 25-50% metal and 75-50% fireproof material, whereby the fireproof material is held together advantageously in case of cracks. The lateral seals according to the invention are reworked or only need to be replaced partly. In this way it is possible to permit longer casting cycles and to recycle parts of the seal.
The cassette-like lateral seals could also be inserted from above instead of from the front in a suitably designed housing or into a holding frame open at the top. In fact the lateral seals according to the invention could also be installed directly into the holding frame without the surrounding sheet, i.e. the cassette structure is not absolutely necessary.
Patent Application
20110132567
