Abstract:
Lateral seal of a casting gap formed between two casting rollers of a strip casting machine that can be placed against the casting rollers on the front face. The lateral seal includes a first moist part and a second part that is assigned to the front faces of the casting rollers. The second part forms a type of snout shape encompassing two legs which extend along the front faces of the casting rollers, join each other at the bottom, above a kissing point, so as to form a common area, and between which the first part protrudes from above. An insulating layer which separates the two parts from each other is inserted between the first and second part.

Description:
FIELD OF THE INVENTION 
     The invention relates to a lateral seal of a casting gap formed between two casting rollers of a strip casting machine which is positioned on a front of the casting rollers and which comprises a first, wetted part and a second part allocated to front sides of the casting rollers whereby the second part has a “snout shape” with two legs which extend along front faces of the casting rollers and join together at the bottom above a kissing point to form a common area between which legs, the first part protrudes from above. 
     BACKGROUND OF THE INVENTION 
     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. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     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 of a casting gap formed between two casting rollers of a strip casting machine, which is positioned on a front of the casting rollers, and which comprises a first, wetted part and a second part allocated to front sides of the casting rollers, whereby the second part has a “snout shape” with two legs which extend along front faces of the casting rollers and join together at the bottom above a kissing point to form a common area, between which legs the first part protrudes from above, and wherein between the first and second parts, an insulating layer is inserted which separates the two parts from one another. 
     In a further preferred embodiment of the lateral seal according to the invention the second part made from a preferably high-temperature-resistant metal is provided with a number of outlet openings for inert gas or lubricants such as oil, grease or graphite-containing coatings connected to a gas or lubricant source, aligned against the front sides of the casting rollers and distributed along the edges of the casting rollers. In another embodiment, the first wetted part is made at least partly from a high-temperature-resistant metal and is provided with a number of outlet openings for inert gas or lubricants such as oil, grease or graphite-containing coatings distributed over its entire surface, aligned against the sealing side and connected to an additional gas or lubricant source. In yet another embodiment, the first wetted part is designed as a metal plate comprising a number of openings distributed over its entire surface, wherein the openings are filled with a fireproof material and the outlet openings for inert gas or lubricants such as oil, grease or graphite-containing coatings are provided between the openings filled with fireproof material. In still another embodiment, the metal plate is provided with centrally protruding nose projecting between the casting rollers, the depth of which decreases from top to bottom. The first wetted part may be composed of a metal plate comprising a number of openings distributed over its entire surface and a fireproof material projecting towards the sealing side and material cast into the openings, wherein the fireproof material forms a plate with cylindrical or differently shaped projections protruding into the openings. The fireproof plate may be provided with a central projecting nose protruding between the casting rollers, the depth of which decreases from top to bottom. Onto the second part made from a high-temperature-resistant metal, a surrounding sheet may be fitted and forms a cassette with the latter which is inserted into a cooled holding frame, and in which the first wetted part is held and surrounded to the rear and along its entire contour with insulation. The second part may bear directly on the cooled holding frame. The two parts are allocated a rear metal plate which comprises the outlet openings of the first wetted part with the gas or lubricant source connecting channels or chambers. The rear plate may include additional connection channels connected to the gas or lubricant source to additional outlet openings arranged in the central common area of the second part, wherein the outlet openings distributed along the casting roller edges of this second part are connected to a separate gas or lubricant source. The first wetted part may consist of 25-50% metal and 75 to 50% fireproof material. The two parts may be provided on the sealing side with a suitable film. On the second part, on the sealing side, a heat and abrasion-proof film may be applied which has stamped holes for the outlet openings. 
     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.). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       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  13   s  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  13   m  (cf. in particular the right half of  FIG. 3 ). The first part  12  projects from above between the two legs  13   s  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  10   a  is shown. Identical parts of this lateral seal  10   a  are denoted by the same reference numbers as in  FIGS. 1 to 5 . The lateral seal  10   a  comprises a wetted first part  12   a  and a snout-shaped second part  13   a , which bear at the rear on a metal plate  37 , wherein the plate  37  is positioned in the depression by spacing pieces  16   a  opposite a surrounding sheet  15  and is separated from the latter by an insulation plate  17   a . The lateral seal  10   a  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  13   a  made from a high-temperature-resistant metal could also advantageously bear directly against the cooled holding frame  11 .) The wetted first part  12   a  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  12   a ,  13   a  are centered relative to one another but separate from one another. 
     The snout-shaped second part  13   a  also comprises further outlet openings  40   a  ( FIGS. 6 and 10 ) in the central area  13   m  in addition to the outlet openings  30 ,  30   m  distributed along the casting roller edges. However, the metal first part  12   a , 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  40   a  in the middle area  13   m  of the second part  13   a  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  10   a′.    
     The outlet openings  40  provided in the wetted first part  12   a  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  10   b  is shown, which comprises a snout-shaped part  13   b  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  12   b  bears on a rear metal plate  37   b . The wetted part  12   b  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  12   b  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  13   b , for which a separate source  45  and connection channels or chambers  55 ,  56  made in the rear plate  37   b  are provided. In this way the wetted first part  12   b  can be provided with an insulating protective film. 
     A lateral seal  10   c  shown in  FIGS. 15 and 16  corresponds essentially to the aforementioned lateral seal  10   b . The first part  12   c  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  10   d  is shown which differs from the one shown in  FIGS. 11 to 14  in that the first wetted part  12   d  (or its metal plate  50   d , the openings  51   d  of which are filled with a fireproof material  52   d ) 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  10   e  shown in  FIGS. 19 and 20  corresponds essentially to the design according to  FIGS. 15 and 16 , however the first wetted part  12   e  has a nose  63   e  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  59   e.    
     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.