Abstract:
A pressure control apparatus includes a main line section and a branch line operably joined to and extending from the main line section. A housing around the branch line has a first wall and a second wall opposed to the first wall, and a first opening is in the first wall. A plug is operably positioned in the branch line, and the plug has a first position that prevents fluid flow through the branch line and a second position that permits fluid flow through the branch line. A loop extends from the plug, and a lever pivotally connected to the second wall and extending through the loop and the first opening in the first wall positions the plug to the first and second positions.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to a pressure control apparatus. In particular embodiments, the apparatus may be used to control pressure in a pipe or vessel, either by relieving or increasing pipeline pressure, without interrupting flow in the pipeline. 
       BACKGROUND OF THE INVENTION 
       [0002]    Piping systems are well-known for conveying fluids or slurries between locations. Common practice in such applications is to provide a tee-piece in the pipeline. The branch of the tee-piece accommodates a plug which is anchored in position to close the branch during normal flow. If it is necessary to relieve an overpressure condition in the pipeline, an anchoring device, such as a clamp, may be released, freeing the plug to retreat in the branch. 
         [0003]    One problem which can be encountered in this operation is rapid release of the plug and pipe contents, creating a danger for personnel in the vicinity. Another potential problem is that slurry conveyed in the pipeline can jam the plug in the branch. Considerable force, for example produced by blasting, may then have to be applied to release the plug. 
         [0004]    The present application seeks to provide an apparatus which addresses one or more of these potential problems. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
         [0006]    In one embodiment of the present invention, a pressure control apparatus includes a main line section and a branch line operably joined to and extending from the main line section. A housing around the branch line has a first wall and a second wall opposed to the first wall, and a first opening is in the first wall. A plug is operably positioned in the branch line, and the plug has a first position that prevents fluid flow through the branch line and a second position that permits fluid flow through the branch line. A loop extends from the plug, and a lever pivotally connected to the second wall and extending through the loop and the first opening in the first wall positions the plug to the first and second positions. 
         [0007]    In particular embodiments, the main line section is configured to connect to opposing sections of the pipeline. In other particular embodiments, the first opening in the first wall includes a first portion and a second portion perpendicular to the first portion, and the lever extends through the first portion when the plug is in the first position and through the second portion when the plug is in the second position. In still further embodiments, the lever extends through a second opening in the second wall, and a locating lug on the lever is engaged with the second opening in the second wall. 
         [0008]    Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which: 
           [0010]      FIG. 1  is a perspective view of a pressure control apparatus according one embodiment of the present invention; 
           [0011]      FIG. 2  is a perspective view of the apparatus shown in  FIG. 1  installed in a pipeline; 
           [0012]      FIG. 3  is a side view of the installed apparatus; 
           [0013]      FIG. 4  is a bottom view of the installed apparatus; 
           [0014]      FIG. 5  is a side view of a plug used in the apparatus; 
           [0015]      FIG. 6  is a perspective view of the plug; and 
           [0016]      FIG. 7  shows a side view of a lever used in the apparatus. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. 
         [0018]    Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made to embodiments of the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0019]    Embodiments of the present invention include a pressure control apparatus  10  that may be used to control pressure in a pipeline conveying mine backfill or slurry. The apparatus  10  generally includes a tee-piece  12  having a main line section  14  and a branch line  16  joined to the main line section. The branch line  16  may be located within a housing  18  with a rectangular cross-section with an open top  20  and an open bottom  22 . Two opposed side walls  24 ,  26  of the housing  18  may be formed by steel plates, and the other two opposed side walls  28 ,  29  may be formed by transparent panels, typically of robust polycarbonate, bolted to flanges carried by the side walls. 
         [0020]    The side walls  24 ,  26  may be formed with arcuate cut-outs at their upper edges that receive the main line section  14  of the tee-piece  12 . One side wall  24  may be formed with an opening  25  of inverted L-shape which has a horizontal portion  25 . 1  and a vertical portion  25 , 2 . The opposite side wall  26  may be formed with a slot-shaped opening  30  and a cover  32  spaced from and extending over this opening  30 . 
         [0021]    As shown in  FIGS. 2-4 , the tee-piece  12  may be connected into a pipeline  34 . This may be achieved by connecting the ends of the main line section  14  to ends of the pipeline  34  by means of clamps  36  such as Victaulic®-type couplings which engage grooves  40  in the ends of the main line section  14  and in the ends of the pipeline  34 . The main line section  14  may have a diameter matching that of the pipeline  34  so that the main line section  14  effectively forms part of the pipeline  34 . 
         [0022]    The branch line  16  may accommodate a plug  42 , seen in more detail in  FIGS. 5 and 6 . The plug  42  may have a cylindrical body  44 , the upper end of which may form a part-cylindrical face  46 . The curvature of the face  46  may correspond to the internal curvature of the main line section  14  and the pipeline  34 . The plug  42  may include a flange  48  at the lower end of the body and a U-shaped loop  50  extending from the flange. A plate  52  may be fixed between the legs of the loop  50 , adjacent the flange  48 . 
         [0023]    The outside diameter of the cylindrical body  44  may be selected such that the plug  42  can be inserted into the branch line  16  as a close slide fit. When the plug  42  is fully inserted, the flange  48  may abut the end of the branch line  16 , and the face  46  may lie flush with the inner surface of the main line section  14 . The plug  42  may be anchored in the fully inserted position by an anchoring device, in this embodiment a Victaulic®-type coupling  54 . 
         [0024]    The coupling  54  may have two generally semicircular shells  54 . 1  and  54 . 2  which are assembled to form a generally circular shape. The ends of the shells may be drawn together in use by means of connecting bolts and associated nuts  58 . In particular embodiments, the assembled coupling  54  may engage a groove at the end of the branch line  16  and the flange  48  of the plug  42 . 
         [0025]    The nuts  58  may be elongate in shape and, in particular embodiments, project through holes in the side wall  24  of the housing  18  so as to be accessible from outside the housing. It will accordingly be understood that the coupling  54  can be tightened or released by application of a suitable spanner or other tool to the projecting ends of the nuts  58 . 
         [0026]    The apparatus of the invention may further include a lever  57 . The lever  57  may have an elongate lever bar  59 , with a handle end  60  at which there is a transverse handle  61  and an opposite end  62  carrying spaced apart, transverse locating lugs  64 . In use, the end  62  of the lever  57  may be inserted into the housing  18  through the L-shaped opening  25  and passed through the loop  50  of the plug  42 . The end  62  may be inserted a short distance through the opening  30  in the housing side wall  26  such that the wall  26  is captive between the lugs  64 . 
         [0027]    During normal operation of the pipeline  34 , the lever bar  59  passes through the horizontal portion  25 . 1  of the opening  25 . In this position, the lever  57  presses up against the lower edge of the plate  52  and thus urges the plug  42  to its fully inserted position. 
         [0028]    If an overpressure condition develops in the pipeline  34  and it is considered necessary to relieve the pressure, the coupling  54  is released by appropriate rotation of the nuts  58 . The plug  42  is, however, still restrained in its fully inserted position by the lever bar  59 . The lever bar  59  can now be moved into alignment with the vertical portion  25 . 2  of the opening  25  and lowered in that portion by manipulation of the handle end  60 . It will be understood that the end  62  of the lever bar  59  pivots relative to the side wall  26  of the housing  18  as the bar  59  is lowered. Lowering of the lever bar  59  allows the plug  42  to withdraw in the branch line  16 , i.e., to move in the branch line  16  in a direction away from the main line section  14 . 
         [0029]    If the plug  42  is locked or jammed in the branch line  16 , possibly by local solidification of the slurry conveyed in the pipeline  34 , the lever  57  may also be forcibly manipulated to free the plug  42 . The bar  59  may, for example, be pivoted forcibly in a downward direction so as to bump or knock against the loop  50  to achieve this. The bar  59  may also be pivoted from side to side so as to bump or knock against the sides of the loop  50  to assist in freeing the plug  42 . 
         [0030]    In practice, the lever  57  may be manipulated so as to allow withdrawal of the plug  42  through a distance sufficient to achieve the required pressure relief. If pipeline  34  pressure is to be increased, the bar  59  can be pivoted upwardly to push the plug  42  upwardly in the branch line  16 . It will accordingly be understood that the lever  57  can be manipulated as necessary, by manual action on the handle end  60 , to control the pipeline  34  pressure. 
         [0031]    At full pressure, the bar  59  may again be located in the portion  25 . 1  of the opening  25  to restrain the plug  42  while the coupling  54  is again applied. As long as the lever bar  59  is in position, the plug  42  cannot withdraw completely from the branch line  16 . The bar  59  accordingly prevents the plug  42  from being ejected suddenly with potentially dangerous consequences. 
         [0032]    If the pipeline  34  is to be vented or drained completely after suitable relief of the pressure in the manner described above, the lever bar  59  may be rotated to align the locating lugs  64  with the length of the opening  30 . The end  62  of the bar can then be pulled back through the opening  30 , through the loop  50 , and through the opening  25 , i.e., the lever bar  59  may be completely withdrawn from the housing  18 . This allows the plug  42  to be removed entirely from the branch line  16 , allowing complete venting or drainage of the pipeline  34  to take place. It will be understood that the reverse procedure is carried out to replace the plug  42  in its fully inserted position. 
         [0033]    The transparent side walls  28 ,  29  of the housing  18  allow an observer to see what is happening inside the housing  18  without being exposed to sudden and dangerous ejection of high pressure slurry or other liquid. The nuts  58  carry flanges  65  which will cover the holes  25  in the side wall  26  through which the nuts  58  pass if the nuts  58  are released. This prevents uncontrolled passage or spray of pressurized liquid through the holes  25 . 
         [0034]    One of ordinary skill in the art will readily appreciate from the preceding description of embodiments of the invention that the apparatus  10  may cause or allow movement of the plug  42  from its fully inserted position to a partially withdrawn position in the branch line  16 , thereby to relieve pressure in the pipeline  34  or vessel without complete removal of the plug  42  from the branch line  16 . Alternately or in addition, the apparatus  10  may cause or allow removal of the plug  42  from the branch line  16 , from either the fully inserted or partially withdrawn position, thereby to allow venting of the pipeline  34  or vessel. Moreover, the apparatus may move the plug  42  from the partially withdrawn position to the fully inserted position, thereby to allow pressure to build up in the pipeline  34  or vessel. 
         [0035]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.