Abstract:
An apparatus for the applying of refractory material in 360 degrees while the apparatus is raised or lowered vertically or inserted and retracted horizontally can apply a layer of material continuously on the interior surface of a hot vessel. Wet mixed refractory material is supplied to an applicator and pressurized air is supplied to the applicator so as to rotate a spinner head on the applicator. The apparatus includes a shroud around the housing of the applicator which conveys the pressurized air around the housing to cool the housing below the temperature of the vessel. Also described is a method of applying refractory material by a spinner head on the applicator in the form of a spray to hot metallurgical vessels such as the snorkel tubes of vacuum degassers and ladles.

Description:
BACKGROUND 
       [0001]    The present invention relates to an apparatus and a method for the applying of monolithic refractory materials. Gunning devices which apply a material onto a target substrate for producing or repairing refractory linings are generally known. 
       SUMMARY OF THE INVENTION 
       [0002]    According to the present invention, an apparatus and a method for the applying of refractory material is provided. 
         [0003]    In some embodiments, an apparatus for the applying of refractory material includes an applicator for continuously applying refractory material 360 degrees in a substantially radial direction. While the applicator is raised or lowered vertically or inserted and retracted horizontally, a layer of refractory material is formed on a preselected area of a target substrate such as the interior surface of a hot vessel. Wet mixed refractory material is supplied to the applicator along with pressurized air. A means for rotating a spinner head of the applicator is provided which can be pressurized air supplied to the applicator which rotates an air rotor which in turn rotates the spinner head of the applicator such that refractory material exits the spinner head in a radial direction. The apparatus includes a means for cooling the housing of the applicator. The means for cooling the housing of the applicator can be a shroud around the housing of the applicator which permits pressurized air supplied to the housing to exit the applicator. The pressurized air passes along the housing and exits the shroud so as to cool the housing below the temperature of the vessel. 
         [0004]    In some embodiments, a method of applying refractory material to a refractory surface or a surface of a metallurgical vessel includes positioning a housing opposite the surface, supplying a wet mixture to the housing, conveying the wet mixture through the housing to a nozzle, rotating the nozzle at a preselected speed, and applying the wet mixture to a preselected area of the target surface in the form of a spray. The wet mixture can be applied through a hoseline and pressurized air can be supplied to the applicator as described above thus permitting the applicator to be moved relative to a target surface. The wet mixture can be applied manually directly by an operator who positions the application such that the wet mixture is sprayed onto a target surface and a sufficient thickness of sprayed coating is built up. In the alternative, a mechanical means can be used to position and move the applicator into a position in which a sufficient thickness of sprayed coating is built up. A mechanical means can be provided which moves the applicator while the spinner head is spinning at a rate sufficient to provide a continuous sprayed coating on the target surface as the applicator moves in the direction of the axis of rotation of the spinning head. 
         [0005]    Refractory material can be applied by the method of the present invention by a spinner head or nozzle of the applicator in the form of a spray to hot or cold surfaces of metallurgical vessels such as ladles, the up and down legs of the snorkel tubes of vacuum degassers as well as vacuum degas vessels. 
         [0006]    After the refractory material has been applied, the sprayed-on lining or layer maintains the refractory lining against attack by corrosive materials such as molten slags and molten metals, especially against attack by acid and basic slags, and steel. 
         [0007]    Application of the refractory material can be performed while the lining material is at a temperature of about 13 degrees Celsius to about 1600 degrees Celsius, in one embodiment about 1200 degrees to about 1500 degrees Celsius. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a description of the Timetable for campaigns conducted with and without the applicator of the present invention in a vacuum degasser; 
           [0009]      FIG. 2  is an illustration of the length of the campaigns or total number of heats prior to relining the vacuum degasser for each of the four phases of  FIG. 1 ; 
           [0010]      FIG. 3  is an illustration of the length of the campaigns or total number of heats prior to relining the vacuum degasser for phase one; 
           [0011]      FIG. 4  is an illustration of the length of the campaigns or total number of heats prior to relining the vacuum degasser for phase two; 
           [0012]      FIG. 5  is an illustration of the length of the campaigns or total number of heats prior to relining the vacuum degasser for phase three; 
           [0013]      FIG. 6  is an illustration of the average length of the campaigns or total number of heats prior to relining the vacuum degasser for each of the four phases; 
           [0014]      FIG. 7  is an illustration of an exemplary applicator of an embodiment of the apparatus of the present invention without an air fitting and showing the spinner head unscrewed from the refractory feed pipe; 
           [0015]      FIG. 8  is a detailed view of vanes of the spinner head showing a plurality of teeth on the vanes; 
           [0016]      FIG. 9  is a plan view of the end cap of the housing of the applicator showing an end cap ring having two flat sides and a bearing; 
           [0017]      FIG. 10  is a plan view of the bearing which fits inside of the housing end cap; 
           [0018]      FIG. 11  is a side view of the housing of the application shown with the housing end cap removed and showing a blade on the air rotor; 
           [0019]      FIG. 12  is a detailed view of a blade showing a tapered angle at both ends of the blade for the air rotor shown in  FIG. 11  after removal from the air rotor; 
           [0020]      FIG. 13  is a plan view of the top face of the air rotor shown in the housing base piece showing blade slots for blades; 
           [0021]      FIG. 14  is a plan view of the exhaust end cap showing the four bolts for joining the exhaust end cap to the housing base piece; 
           [0022]      FIG. 15  is a side view of the exhaust end cap with the bolts removed and showing the inner face and sidewalls which define a cavity in the exhaust end cap for the air rotor; 
           [0023]      FIG. 16  is a side view of the housing base piece shown with the air rotor inside and a retaining ring on a threaded portion of the air rotor end shaft; 
           [0024]      FIG. 17  is a side view of the air rotor showing the blade slot; 
           [0025]      FIG. 18  is a perspective view of the housing base piece showing a step-shaped structure on the interior of the housing base piece side wall; 
           [0026]      FIG. 19  is an elevation view of the apparatus for use in an exemplary process according to one embodiment of the present invention; 
           [0027]      FIG. 20  is a plan view of the inner sleeve of the applicator; 
           [0028]      FIG. 21  is a perspective view of the applicator of the present invention showing the spraying of a wet mixture of refractory material for forming a refractory lining on a target surface; 
           [0029]      FIG. 22  is a perspective view of an operator spraying refractory material using the applicator of the present invention; 
           [0030]      FIG. 23  is a side elevational view showing a system for providing a coating of refractory material to a horizontal ladle; and 
           [0031]      FIG. 24  is a parallel perspective view of a system for providing a coating of refractory material to a ladle in the vertical position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    The invention will now be described in detail by reference to the following specification and non-limiting examples. Unless otherwise specified, all temperatures are in degrees Celsius. 
         [0033]    Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. 
         [0034]    Referring now to the drawings in detail, wherein like reference numerals indicate like elements through the several views, there is shown in  FIG. 7  an applicator  10  according to the present invention having a housing base piece  12  attached to end cap  14  and exhaust cap  16 . Shroud base piece  18  supports shroud  20  which surrounds housing  22 . Shroud  20  shown here substantially cylindrically can be any shape or configuration so as to provide a means for permitting the passage of gas, here air, along the housing  22  of the applicator  10  so as to cool housing  22 . Inner wall  24  of shroud  20  defines the contour or the passageway  28  by which air exits the open shroud end  26  in the direction shown by the arrows in the passageway  28 . Air fitting  30  which extends through shroud base piece  18  fits up to exhaust cap  16  and provides a supply of air to applicator  10  which rotates rotor  32  shown in  FIG. 17  as described below. 
         [0035]    Inner sleeve  34  which extends through the length of applicator  10  provides a means for transferring wet mix, here refractory material to be applied to a target surface, for example on interior snorkel surface  36  on Rheinstahl Heraeus degasser snorkel  38  as seen in  FIG. 19 . 
         [0036]    Air rotor head pipe  40  which rotates together with air rotor  32  has rotor head pipe threaded portion  42  which provides a means for fastening to spinner head  44  at an interior threaded portion (not shown) on spinner head base piece  46 . Vanes  48  which are connected to spinner head base piece  46  are in turn attached to spinner head face piece  50 . Spinner head nut  120  engages spinner head bolt  124  which is adjacent to spinner head washer  122  thus permitting adjustment of the flow characteristics of the wet refractory material flowing toward spinner head interior face during operation of the applicator  10  through the use of spinner head washers  122  of different thickness or number and spinner head bolts of different sizes. 
         [0037]    During operation of the applicator  10 , wet mix which is pumped to inner sleeve  34  passes through spinner head aperture  52  where the wet mix engages interior spinner head face  54  of spinner head  44 . Wet mix which exits inner sleeve  34  flows toward interior spinner head face  54  and between vanes  48  of spinner head  44  which rotates during operation. As spinner head  44  rotates the rotating action of vanes  48  spray a coating of wet mix, here refractory material in the radial direction as spinner head  44  rotates about an axis as seen in  FIG. 19 . 
         [0038]    Operation of the applicator  10  and the means for rotating the spinner head  44  here, by air rotor  32  can be understood by way of an explanation of how to disassemble the housing  22 . After unscrewing exhaust end cap pipe  60  from shroud base piece  18  from exhaust cap threaded portion  62 , inner sleeve  34  can be removed from the inside of the exhaust end cap pipe  60 , if necessary by gripping inner sleeve fitting  34   a  and twisting the inner sleeve. End cap  14  can then be removed from the remaining portion of the housing  22  by removing two allen bolts (not shown) from end cap aperture  64 . 
         [0039]    As seen in  FIG. 9 , retaining ring  66  has retaining ring flat sides  68 . Retaining ring  66  has retaining ring groove  70  on each face which serves to align bearing top portion  72  of bearing  74  which has the form of a truncated cone. In one embodiment, bearing  74  has ball bearings  76  as shown in  FIG. 10 . Now that end cap  14  has been removed, blades  78  can be removed from a friction fit as shown in  FIG. 11  from blade slots  80  as seen in  FIG. 13 . The blades  78  have tapered portion  82 . 
         [0040]    At an opposite end of the housing from the blades  78  is exhaust cap  16 . As seen in  FIG. 14 , four hexagonal bolts  84  are removed to separate housing base piece  12  from exhaust cap  16 . Six exhaust cap apertures  85  are located together along the perimeter of exhaust cap  16  so as to provide a passageway for the pressurized air to exhaust after traveling over blades  78  resulting in the rotation of air rotor  32 . Also aiding in the rotation of the air rotor  32  is the offset configuration of blades slots  80  in air rotor  32  which hold blades  78 . 
         [0041]    As shown in  FIG. 16 , rotation of air rotor  32  independent of the housing  22  is achieved by the engagement of retainer nut  86  on a threaded portion of air rotor exhaust end pipe  88  such that retainer nut  86  does not rotate relative to air rotor  32  but does indeed rotate relative to housing base piece  12 .  FIG. 18  depicts housing base piece  12  having internal ridges  90  and setback edge  92  which permits fitup of end cap  14 . Housing base piece  12  is provided with apertures  94  to accommodate allen bolts to connect with end cap  14 . 
         [0042]    In another embodiment of the apparatus of the present invention, the vanes  56  of spinner head  44  have teeth  58  as seen in  FIG. 8  rather than extending continuously from spinner head base piece  46  to spinner head face piece  50 . 
         [0043]    In yet another embodiment of the present invention, the spinner head  44  can be driven by a motor such as an electric motor or a hydraulic motor. 
         [0044]    As seen in  FIG. 19 , in operation, pressurized air is provided at air fitting  30  through air line  96 . Dry refractory material is placed in the hopper  98  of mixer unit  100  which has control panel  102  and mixer  104  for mixing a wetting agent such as water and dry refractory material. During operation of the mixer, wetted refractory material is pumped at mixer fitting  110  through hoseline  106  which is supported by supporting means  108 . The supporting means can be any means for supporting the hoseline  106  or conveying means for the wetted refractory material which permits movement of the applicator for operation of the application at a preselected location. Here the supporting means includes vertical member  108  and a clamping means for engaging hoseline  106 . The clamping means is a horizontal member  126  having a semicircular shaped cutout portion for accommodating a portion of the circular cross-sectional profile of the hoseline  106 . The clamping means includes bolt clamping means  112  and clamping means nut  114 . 
         [0045]    In  FIG. 19  the means for moving the applicator to a preselected operating position to apply refractory material to a preselected target surface is a forklift  116  which has forks  118  which can be raised and lowered by a forklift operator. In another embodiment, the applicator can be held at the same location while the target surface is raised, lowered or moved in any direction having vertical and/or horizontal components while the target surface is coated by the applicator. 
         [0046]    In another embodiment, both the applicator and the target surface can each be moved in a direction having a vertical and/or horizontal component during coating of the target surface by the applicator. 
         [0047]    In yet another embodiment, the applicator can be moved in a direction having a vertical and/or horizontal component while the target surface is coated by the applicator. 
         [0048]    In another embodiment, mechanical means other than a forklift can be used to raise and lower the applicator. 
       EXAMPLE 1 
       [0049]    As stated in  FIG. 1 , in Phase 1, an RH vacuum degasser was maintained using OPTISHOT® SP and ECOSHOT™ 30 refractory materials of Minteq International Inc. of New York, New York using grouting techniques. As can be seen in  FIGS. 2 ,  3  and  6 , the average length of a campaign of heats of the RH vacuum degasser until the end of the campaign (EOC) was 123. 
       EXAMPLE 2 
       [0050]    As stated in  FIG. 1 , in Phase 2, the up and down snorkel legs of an RH vacuum degasser were maintained using OPTISHOT® SP-FG refractory material and grouting techniques. As can be seen in  FIGS. 2 ,  4  and  6 , the average length of a campaign of heats of the RH vacuum degasser until the end of the campaign (EOC) was 149. 
       EXAMPLE 3 
       [0051]    As stated in  FIG. 1 , in Phase 3, the up and down snorkel legs of an RH vacuum degasser were maintained using OPTISHOT® SP-FG refractory material using an applicator of the present invention having a spinner head. The applicator used an Airline AL-20 spinning nozzle on a two and one-half meter long shaft which is available from Blastcrete of Anniston, Ala. The applicator was mounted vertically on a two and one-half meter long shaft and a one-inch pipe fed wet mixed refractory material to the applicator and a one-half inch air line was supplied to the applicator to power the air rotor. As can be seen in  FIGS. 2 ,  5  and  6 , the average length of a campaign of heats of the RH vacuum degasser until the end of the campaign (EOC) was 171. 
       EXAMPLE 4 
       [0052]    As stated in  FIG. 1 , in Phase 4, the up and down snorkel legs of an RH vacuum degasser were maintained using OPTISHOT® SP-FG refractory material using an applicator of the present invention having a spinner head. The applicator used an Airline AL-20 spinning nozzle which is available from Blastcrete of Anniston, Alabama and a Duo Mix 2000 mixerunit from M-Tec Mathis Technik GmbH of Neuenberg, Germany. As can be seen in  FIGS. 2 and 6 , the average length of a campaign of heats of the RH vacuum degasser until the end of the campaign (EOC) was 177. In the alternative, other mixer units such as a Mix-O-Mat mixer unit from Minteq International Inc. can be used. 
         [0053]    The above testing coatings were applied as a refractory lining. The linings met or exceeded the performance requirements in the areas of density, strength, drying, resistance to cracking, preheating, molten metal and resistance, durability and sequencing requirements. 
         [0054]    In an embodiment of the invention, the applicator can coat monolithic refractory material on an interior surface of a metallurgical vessel or body while the body is still heated. The temperature of the target surface to be fabricated or repaired by the method of the present invention or by the apparatus of the invention to coat or line the surface can be any surface from a cold surface to a hot surface. In one embodiment, the target surface can be at from about 1200 to about 1500 degrees Celsius. 
         [0055]    In the method of the invention, application of the coating can be applied to provide a layer of refractory lining of a thickness from about one to three centimeters to about three to eight centimeters both prior to exposing as well as after exposing the lining to corrosive materials. The providing of thicker refractory linings permits a reduction in the frequency of applications required to maintain the metallurgical vessel or structure. The applicator can be raised and lowered relative to the target surface repeatedly until the desired thickness of the coating is provided. 
         [0056]    The structure to be coated or lined can be a cylindrical body such as a ladle, a vacuum degasser snorkel or a vacuum degasser vessel. 
         [0057]    In one embodiment, material was applied by the applicator at a rate of from about 55 to about 75 kilograms per minute. 
         [0058]    In another embodiment, the interior surface of a ladle or CAS-OB bells used in metallurgical operations can be lined with refractory material using the method and apparatus of the present invention by providing a means for supporting the applicator and a means for providing relative movement of the ladle with respect to the applicator. 
         [0059]    As seen in  FIG. 22 , an operator  128  is shown supporting the hoseline  106  which provides a wet mixture of refractory material to the applicator  10  in such a manner so as to spray a coating of refractory material to the interior surface  130  of ladle  132  which is in the horizontal position. The system shown in  FIG. 22  can be used to provide a refractory lining to the interior surfaces of a ladle which is at room temperature or at temperatures at which an operator can safely carry out the method shown in  FIG. 22 . 
         [0060]    In  FIG. 23  a means for supporting the applicator of the present invention is shown such that the interior surfaces of the walls of a metallurgical vessel, here a ladle  132  in the horizontal position having trunions  138 , can be sprayed with refractory material. A scissors lift truck  134  having lift platform  136  supports members  108  and a clamping means for engaging hoseline  106 . The clamping means is a horizontal member  126  having a semicircular shaped cutout portion for accommodating a portion of the circular cross-sectional profile of the hoseline  106 . The clamping means includes bolt clamping means  112  and clamping means nut  114 . 
         [0061]    In yet another embodiment as seen in  FIG. 24  a means for supporting the applicator of the present invention is shown such that the interior surfaces of the walls of a metallurgical vessel, here a ladle  132  in the vertical position having trunions  138 , can be sprayed with refractory material. A jib crane  140  having support member  142  supports electric motor  144  which has a means for raising and lowering rigid hoseline  106   a.  The rigid hoseline  106   a  can be substantially rigid. The means for raising and lowering the rigid hoseline  106   a  can be motor chain  152  which is pulled and released by an electromechanical drive motor (not shown) which is operated by an operator. 
         [0062]    The electric motor  144  also has a means for moving the electric motor  144  along support member  142  in order to position the rigid hoseline  106   a  at the center of the ladle  132  at a vertical axis of the ladle  132 . The means for moving the electric motor  144  along the support member  142  can be a chain (not shown) which permits an operator to pull electric motor  144  along support member  142 . 
         [0063]    The jib crane  140  can have a means for pivoting support member  142  into a predetermined position such that electric motor  144  supports hoseline  106   a  and applicator  10 . The means for pivoting support member  142  is hinge pin  150 . 
         [0064]    Ladle  132  can have a means for supporting ladle  132 , here ladle support  146  which engages ladle ring  148  which provides a means for maintaining ladle  132  into a position. 
         [0065]    Application of the refractory material can be performed prior to initial exposure of the refractory lining to the corrosive materials. Depending on the degree of erosion and/or corrosion of the lining formed on the refractory material, the refractory material of the present invention need not necessarily be reapplied to the refractory material after each run of corrosive materials over the refractory lining. 
         [0066]    Accordingly, it is understood that the above description of the present invention is susceptible to considerable modifications, changes and adaptations by those skilled in the art, and that such modifications, changes and adaptations are intended to be considered within the scope of the present invention, which is set forth by the appended claims. 
         [0067]    This apparatus can be used in applications outside of those for fabricating or repairing refractory linings.