Abstract:
A seal arrangement includes a body having at least two walls defining a cavity, the walls are engagable with at least one structure through expansion of the body, and graphite is sealingly engaged with the body and the structure and resiliently compressively maintained within the cavity by the at least one structure.

Description:
BACKGROUND 
       [0001]    Elastomers are commonly used to seal members to one another because of their ability to seal to surfaces that are rough or include imperfections. Applications for such seals include tubular systems employed in earth formation boreholes such as in the hydrocarbon recovery and carbon dioxide sequestration industries. Such seals however can degrade at high temperatures and high pressures and in corrosive environments. Operators, therefore, are always receptive to new sealing arrangements and methods that overcome these shortcomings. 
       BRIEF DESCRIPTION 
       [0002]    Disclosed herein is a seal arrangement. The seal arrangement includes a body having at least two walls defining a cavity, the walls are engagable with at least one structure through expansion of the body, and graphite is sealingly engaged with the body and the structure and resiliently compressively maintained within the cavity by the at least one structure. 
         [0003]    Further disclosed herein is a method of sealing. The method includes, positioning graphite within a cavity defined by walls of a body, expanding the body, engaging at least one structure with the walls, expanding the graphite, compressing the graphite against the at least one structure and sealing the graphite to the at least one structure and the body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0005]      FIG. 1  depicts a partial cross sectional view of a seal arrangement disclosed herein in a sealing position; 
           [0006]      FIG. 2  depicts a partial cross sectional view of an embodiment of the seal arrangement of  FIG. 1  in a non-sealing position; 
           [0007]      FIG. 3  depicts a partial cross sectional view of an alternate embodiment of the seal arrangement of  FIG. 1  in a non-sealing position; 
           [0008]      FIG. 4  depicts a partial cross sectional view of an alternate seal arrangement disclosed herein; 
           [0009]      FIG. 5  depicts a partial cross sectional view of another alternate seal arrangement disclosed herein in a non-sealing position; and 
           [0010]      FIG. 6  depicts a partial cross sectional view of the seal arrangement of  FIG. 5  in a sealing position; 
           [0011]      FIG. 7  depicts a partial cross sectional view of an alternate embodiment of a seal arrangement disclosed herein with a portion thereof shown at a greater magnification; 
           [0012]      FIG. 8  depicts a perspective view of an alternate embodiment of a seal arrangement disclosed with the body and outer structure removed; and 
           [0013]      FIG. 9  depicts a perspective view of the embodiment of  FIG. 8  at a different position. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0015]    Referring to  FIG. 1 , an embodiment of a seal arrangement disclosed herein is illustrated generally at  10 . The seal arrangement  10  includes expandable graphite  14  positioned within a cavity  18  in a body  22 , and the graphite  14  sealably engages with a structure  26  proximate an opening  30  in the body  22 . The graphite  14  is volumetrically expandable in response to specific changes in environment such as changes in temperature, for example. Volumetric expansion of the graphite  14  causes it to be forcedly engaged with walls  34  of the body  22  as well as to forcedly engage with a surface  38  of the structure  26 . The graphite  14  is deformable such that it conforms to troughs  42 , peaks  46  and other imperfections in the surface  38  creating a seal between the graphite  14  and the structure  26  in the process. The graphite  14  also seals to the walls  34  of the body  22  thereby resulting in the body  22  being sealably engaged to the structure  26 . The graphite  14  is configured to plastically deform at loads below where it elastically deforms. And it is the plastic deformation that allows the graphite  14  to contour to the surface  38  and form a seal therewith. 
         [0016]    The graphite  14  in its expanded state is compressible and therefore has resiliency. This resiliency allows it to maintain loading against the body  22  and the structure  26  and maintain sealing thereto even during changes in the volume of the cavity  18 . An optional second compressible member  50  can be positioned within the cavity  18  that also is resilient and therefore provides additional compressive forces to the graphite  14 . Although other embodiments are contemplated, the resilient member  50  in this embodiment is a tubular shaped hoop with a compressible fluid  54  sealed therewithin. As forces on the resilient member  50  flatten the cross sectional shape that is initially round, the decrease in volume of the compressible fluid  54  causes pressure therein to resiliently increase. 
         [0017]    Referring to  FIG. 2 , an embodiment of the seal arrangement  10  is illustrated at a position prior to the graphite  14  being sealingly engaged with the structure  26 . In this embodiment, the structure  26  is a tubular with only a small portion of a quarter cross section being shown. The surface  38  of the structure  26  in this case is the inner radial surface of the tubular  26 . A second tubular  58  is positioned radially within the structure  26  and substantially concentric with the structure  26 . An outer radial surface  62  of the second tubular  58  has a ramped portion  66 , which is frustoconical such that radial dimensions of the outer ramped portion  66  increase toward the right side of the Figure. The body  22 , when moved rightward in the Figure, has an inner radial face  70  that engages with the surface  62  and radially expands as the rightward movement continues. Walls  74  of the body  22 , which are substantially perpendicular to the face  70  in this embodiment, also grow radially as the body  22  is moved relative to the ramped portion  66 . After sufficient radial growth the walls  74  engage with the surface  38  of the structure  26 , thereby enclosing the cavity  18  and encasing the graphite  14  therewithin while allowing fluids or gases to escape. Volumetric expansion of the graphite  14  causes it to fill the cavity  18  and generate compressive forces against the surface  38 . These compressive forces are sufficient to sealingly engage the graphite  14  with the surface  38  even when the surface  38  includes the troughs  42  and peaks  46  discussed above in reference to  FIG. 1 . 
         [0018]    It should be noted that the volume of the cavity  18  increases as the radial dimensions of the body  22  increase prior to engagement of the walls  74  with the structure  26 . The expansion of the graphite  14  is selected to be greater than the volumetric increase of the cavity  18  and as such the graphite  14  is able to fill the increased sized cavity  18 . In fact, the graphite  14  can expand between about 50% and 200% in volume. 
         [0019]    Referring to  FIG. 3 , an alternate embodiment of the seal arrangement  10  is illustrated at a position prior to the graphite  14  being sealingly engaged with the structure  26 . This embodiment is similar to that of  FIG. 2  with the primary difference being that the graphite  14  in this embodiment is expanded prior to the body  22  being moved up the ramped portion  66  into engagement with surface  38 . In this embodiment some of the graphite  14  may be “wiped” out of the cavity  18  as the graphite  14  contacts the surface  38  prior to the walls  74  contacting the surface  38 . This condition does not alter the function of the embodiment since enough of the graphite  14  will be radially compressed into the cavity  18  via contact with the surface  38  prior to engagement of the body  22  with the structure  26  to generate the resilient forces in the graphite  14  sufficient to cause the graphite  14  to seal to both the surface  38  and the body  22 . Other embodiments (not shown) can incorporate elements of both  FIG. 2  and  FIG. 3  in that the graphite  14  can expand both before the walls  74  engage the surface  38  and after. 
         [0020]    Referring to  FIG. 4 , an alternate embodiment of a seal arrangement disclosed herein is illustrated at  110 . The seal arrangement  110  differs from the seal arrangement  10  in that a body  122  that defines cavity  118  containing the graphite  14  has two openings  130 . One of the openings  130  faces radially outwardly in a fashion similar to that of the earlier describe embodiments, and one of the openings  130  faces radially inwardly. Resilient forces, due to the volumetric compression of the graphite  14  within the cavity  118 , cause the graphite  14  to sealingly engage with the surface  38  and the outer radial surface  62  of the second tubular  58  in addition to walls  174  of a body  122 . Note in this embodiment the compressive forces are generated by the graphite  14  alone since a version of the second resilient member  50  is not employed. Additionally, structural members  132  (one being shown in phantom) of the body  122  extend through the graphite  14  while holding the walls  174  a fixed distance apart without detrimentally affecting the functioning of the seal arrangement  110 . 
         [0021]    Referring to  FIGS. 5 and 6 , an alternate embodiment of a seal arrangement disclosed herein is illustrated at  210 . The seal arrangement  210  includes two structures  226 ,  258  that are sealable to one another by a body  222  and the expandable graphite  14 . The body  222  defines a cavity  218  that houses the graphite  14 . The body  222  includes an opening  230  that is closed by engagement of walls  274  of the body  222  with a surface  238  that in this embodiment is an inner radial surface of a tubular that is the first structure  226 . At least one of two frustoconically oriented legs  224  of the body  222  slidingly engage with an outer radial surface  262  of the second structure  258 . Longitudinally moving ends  228  of the legs  224  toward one another causes the walls  274  to move radially outwardly until they engagably contact the surface  238 , thereby enclosing the graphite  14  within the cavity  218 . The graphite  14  as shown in  FIG. 5  (in the non-sealing position), is already volumetrically expanded such that a portion of it extends through the opening  230  and outside of the cavity  218 . Simultaneously moving both of the legs  224  can cause the graphite  14  to move radially only into contact with the surface  238  thereby avoiding any scrapping of the graphite  14  with the surface  238  that would occur if there were relative longitudinal movement therebetween during the enclosing of the cavity  218 . The foregoing allows the graphite  14  to become directly radially compressed into the cavity  218  as the walls  274  become engaged with the surface  238  as illustrated in  FIG. 6 . 
         [0022]    It should be noted that although the graphite  14  was expanded prior to enclosing it within the cavity  218 , as evidenced by  FIG. 5 , the graphite  14  could be expanded after the cavity  218  has been enclosed by the surface  238  as was done in the embodiment illustrated in  FIG. 2 . 
         [0023]    Referring to  FIG. 7 , an alternate embodiment of a seal arrangement disclosed herein is illustrated at  310  in cross section with a small portion shown magnified. The primary difference between the seal arrangement  310  and those of the embodiments discussed above is that the graphite  14  in this embodiment is in the form of a plurality of slabs  316 . The slabs  316  are oriented in the cavity  18 ,  118 ,  218  of the body  22 ,  122 ,  222  such that faces  320  on opposing sides of the slabs  316 , across the smallest dimension of the slabs  316 , abut the faces  320  on slabs  316  perimetrically adjacent thereto. Thus the slabs  316  are stacked in this manner such that they substantially fill the full 360 degrees of the cavity  18 ,  118 ,  218 . 
         [0024]    Referring to  FIGS. 8 and 9 , another alternate embodiment of a seal arrangement disclosed herein is illustrated at  410 . The arrangement  410  is similar to the arrangement  310  with the primary difference being the shapes of slabs  416  of the graphite  14 . In this embodiment opposing faces  420  do not face directly 180 degrees from one another as they did in the arrangement  310  but instead are form an angle such that a cross section taken longitudinally through one of the slabs  420  substantially forms a trapezoid. Additionally, every other one of the slabs  420  distributed along the cavity  18 ,  118 ,  218  is flipped  180  degrees relative to both its neighbors. This orientation allows the faces  420  to remain abutted to one another as the slabs are moved radially outward such as along ramped portion  466  of tubular  458 , for example. Allowing the faces  420  to remain abutted while they are moved radially outwardly may allow sealing to occur between the adjacent slabs  416  with less deformation of the slabs  416 . 
         [0025]    In some embodiments disclosed herein the graphite  14  employed is expandable graphite. One example of expandable graphite usable as the graphite  14  is disclosed in copending U.S. patent application Ser. No. 14/072016 filed Nov. 5, 2013 assigned to the same assignee as this application, the entire contents of which are incorporated herein by reference. 
         [0026]    While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.