Abstract:
The present invention is a plug system having a plug for insertion into a pipeline, wherein the plug system is insertable via a fitting attached to the pipeline. A pre-drilled aperture of the pipeline positioned normal to the cylindrically-shaped pipeline may interfere with a pig traveling through the pipeline. In one embodiment, the plug includes two coaxial cylindrical portions. A first cylindrical portion has a diameter greater than the aperture diameter, while the second cylindrical portion has a diameter less than the aperture diameter. Additionally the plug defines a hole that is oriented perpendicular to an axis of the cylindrical portions, wherein the diameter of the hole is approximately the size of inside diameter of the pipe. The plug has a retaining member to stabilize the plug system. When the plug is installed in the pipe it permit a pig to flow freely, thereby eliminating pigging hazards.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims benefit, under 35 U.S.C. § 119(e), of U.S. Provisional Application Ser. No. 60/705,364, filed 4 Aug. 2005, the entire contents and substance of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to pipeline fittings and, more particularly, to an installable, insertable fitting plug system adapted to permit a pipeline pig to freely pass by the fitting and eliminate pigging hazards.  
       BACKGROUND OF THE INVENTION  
       [0003]     The Pipeline Safety Improvement Act of 2002 regulates management of gas transmission pipelines integrity. The Act, codified in 49 C.F.R. Part 192, significantly increased the complexity and cost of operating pipelines. Some stated objectives of the gas integrity management include improving pipeline safety through accelerating the integrity assessment of pipelines in high consequence areas; improving the government&#39;s role in reviewing adequacy of integrity programs and plans; and proving increased public assurance in pipeline safety. These regulations altered the integrity characteristics of new pipelines, and demanded the repair of many existing pipelines.  
         [0004]     When repairing pipelines, it is often necessary to inhibit flow of product in the pipeline, and isolate pressure by inserting a stopping plug into the pipeline from, for example, a hot-taped fitting. Various types of the conventional plugs or pipeline stoppers exist and are widely used. When the repair work is finished, the stopper is removed and a completion plug is installed, sealing the fitting.  
         [0005]     Some fittings, used for stopping flow, require the drilling of a hole through one pipe wall, while others require drilling through opposing walls. These openings, especially those with large diameters, might create a problem with running a pig through the pipeline. A pig is a device inserted into a pipeline that is designed to travel freely through it, driven by product flow to perform a specific task within the pipeline, e.g., remove wall debris, assess wall thickness, and/or assess wall deformation. Oftentimes, with conventional fittings in a pipeline, a pig can not pass through the fitting and may become lodged. To avoid potentially damaging the pig, or clogging the pipe with a lodged pig, the pig must be removed from the pipeline at a location short of the fitting, and then reinserted into the pipeline at a downstream position. This approach results in a significant loss of time and a potential loss of substantial profits, which are normally derived from use of the pipeline.  
         [0006]     One existing solution to these problems is a type of a completion plug exemplified by T. D. Williamson Inc.&#39;s Lock-O-Ring plug. This plug utilizes the original coupon of the pipeline cut to form the opening. The coupon is welded to a completion plug and, by being installed in a fitting, attempts to smooth the inside walls of the pipeline and therefore enable the pig to travel through the fitting.  
         [0007]     There are some limitations with to this type of plug. One limitation includes the inability to use it with threaded completion plugs, because orienting the coupon inside the aperture during the installation process is not possible. Another limitation includes the inability to use the Williamson plug with pipes that have or will have holes in diametrically opposed walls.  
         [0008]     Thus, there is a need in the art for a plug, insertable into a pipeline from a fitting that enables pigs to flow freely through the fitting, while eliminating pigging hazards. It is to such a device that the present invention is primarily directed.  
       SUMMARY OF THE INVENTION  
       [0009]     A pipeline can transfer product, e.g., gas or liquid, from a first position to a second position. In transferring gas or liquid, waste occasionally builds up inside the pipe, typically along walls of the pipe. Additionally, a pipe wall may begin to deteriorate depending on the type of environment the pipe resides and/or the product the pipe carries.  
         [0010]     As a result, a pig is commonly inserted into the pipe to clean the walls of the pipe or assess characteristics, i.e., wall thickness and/or deformation of the pipe. The pig is driven by the product flowing inside the pipe.  
         [0011]     Pipes commonly have apertures along the length of the pipe. These apertures are created for access into the pipe for different purposes. Unfortunately, as a result of these apertures, pigs can fall off the center line of the pipe, or the path of the pig. As a result, the pig can become lodged in a fitting. Additionally, sensors attached to the pig may be damaged or even destroyed by sharp edges of the apertures. A lodged or damaged pig can result in significant time loss in using the pipeline and/or a potential loss of profits derived from the pipeline.  
         [0012]     Generally described, the present invention comprises a plug system enabling a pig to flow freely through a pipeline at locations of pipeline apertures.  
         [0013]     In an exemplary embodiment of the present invention, a plug system is used to enable a pipeline pig to pass freely though sections of the pipeline having apertures, which would otherwise hinder the travel of the pig. In an exemplary embodiment, the plug system includes a plug having two coaxial cylindrical portions; a hole, oriented perpendicularly to the axis of the cylindrical portions; and means for connecting inserting and extracting tools as well as for the plug positioning on the pipe. The first cylindrical portion of the plug system is larger than the diameter of an aperture in the pipeline. The second cylindrical portion of the plug system is smaller than the diameter of the aperture in the pipeline. The axis of the two cylindrical portions is positioned parallel to the axis of aperture. The hole diameter is approximately equal to the pipe inside diameter. The plug can be adapted by a fitting enabling a pig to flow freely through the pipeline and past the apertures.  
         [0014]     In an exemplary embodiment, the plug can include a plurality of slots. The slots secure product flow to available branches, connected to the bottom or side outlets of the fitting.  
         [0015]     Further, the plug system can include a retaining member for stabilizing the plug within the pipe.  
         [0016]     These and other objects, features, and advantages of the present invention will become more apparent upon reading the following specification in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a vertical cross-sectional view illustrating a pipeline stopping fitting, shown in place on a pipe after a stopping procedure was completed.  
         [0018]      FIG. 2  is a vertical cross-sectional view illustrating the pipeline fitting with a plug system, in accordance with an embodiment of the present invention.  
         [0019]      FIG. 3  illustrates a front view of the plug, in accordance with an embodiment of the present invention.  
         [0020]      FIG. 4  illustrates a side view of the plug, in accordance with an embodiment of the present invention.  
         [0021]      FIG. 5  is a sectional view of the plug, taken from the line B-B in  FIG. 4 .  
         [0022]      FIG. 6  is a sectional view of the plug, taken from the line A-A in  FIG. 3 .  
         [0023]      FIG. 7  is a vertical cross-sectional view illustrating the pipeline stopping fitting, shown in place on a pipe after a stopping procedure was completed, and further illustrating the pipeline having a fitting with a bottom outlet.  
         [0024]      FIG. 8  is a vertical cross-sectional view illustrating the pipeline fitting with a plug system, further illustrating the pipeline stopping fitting having the bottom outlet housing an insertable plug with a plurality of slots, in accordance with an embodiment of the present invention.  
         [0025]      FIG. 9  is a sectional view taken from the line B-B in  FIG. 4  illustrating the plug having slots, in accordance with an embodiment of the present invention.  
         [0026]      FIG. 10  is a sectional view taken from the line A-A in  FIG. 3  illustrating the plug having slots, in accordance with an embodiment of the present invention.  
         [0027]      FIG. 11  illustrates a top view of the insertable plug with slots, in accordance with an embodiment of the present invention.  
         [0028]      FIG. 12  illustrates a bottom view of the insertable plug with slots, in accordance with an embodiment of the present invention.  
         [0029]      FIG. 13  is a sectional view of the plug, taken from the line A-A in  FIG. 3  further illustrating the plug having reinforcing inserts, in accordance with an embodiment of the present invention.  
         [0030]      FIG. 14  is a close up of a sectional view taken from the line C-C in  FIG. 13 .  
         [0031]      FIG. 15  illustrates a front view of the plug system, in accordance with an embodiment of the present invention.  
         [0032]      FIG. 16  illustrates a front view of the plug for the pipeline having one aperture, in accordance with an embodiment of the present invention.  
         [0033]      FIG. 17  illustrates a side view of the plug, for the pipeline having one aperture, in accordance with an embodiment of the present invention.  
         [0034]      FIG. 18  is a sectional view taken from the line B-B in  FIG. 17 .  
         [0035]      FIG. 19  is a sectional view taken from the line A-A in  FIG. 16 .  
         [0036]      FIG. 20  illustrates a front view of the plug for the pipeline having one aperture, in accordance with an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0037]     The present invention includes a plug system that is insertable into a pipeline from a fitting, through a pipeline wall aperture. Preferably, the pipeline has a straight longitudinal axis and circular cross-section. The pipeline can further have at least one aperture positioned normal to the flow of product in the pipeline. In a preferred embodiment, the pipeline is adapted to receive a pig.  
         [0038]     A plug of the plug system can include a body portion in communication with the circumferential outer surface of the pipe. Further, the plug can have a first cylindrical portion, or a large cylindrical portion, having a diameter that is greater than the diameter of the aperture. Additionally, the plug can have a second cylindrical portion, or a small cylindrical portion, having a diameter less than the aperture diameter. The plug of the plug system enables a pig to flow freely through the pipeline, and pass the aperture(s) without interference.  
         [0039]     The materials described hereinafter as making up the various elements of the invention are intended to be illustrative and not restrictive. Many suitable materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of the invention. Such other materials not described herein can include, but are not limited to, for example, materials that are developed after the time of the development of the invention.  
         [0040]     Referring now to the figures, wherein like reference numerals represent like parts throughout the several views,  FIG. 1  is a vertical cross-sectional view illustrating a pipeline stopping fitting, shown positioned on a pipe. A pipe or pipeline  100  preferably has a straight longitudinal axis and a circular cross section, wherein product or media, e.g., gas or liquid, normally can flow in the direction shown by the arrow.  
         [0041]     If it is desired to stop such a flow of the product through the pipe  100  or through a particular section thereof, a plugger (not illustrated) can be employed from the stopping fitting  105  and be preliminarily installed on the pipe  100 . The stopping fitting  105  can be attached to the pipe  100  using a conventional method such as mechanical joint, welding, and the like. In order to have access into the pipe  100 , or insert objects into the pipe  100 , at least one aperture  110  in a wall of the pipeline  100  can be created. The axis of the aperture  110  is perpendicular to the product flow (as illustrated by the arrow in  FIG. 1 ). In an exemplary embodiment, a second aperture  115  in a wall of the pipeline  100  can also be created. The aperture  110  enables the plugger (not illustrated) to be inserted into the pipe  100  from the fitting  105 .  
         [0042]     The apertures  110  and  115  can be formed by conventional well-known methods, including, for example, a circular cutter capable of removing the coupons from the pipe  100 . One skilled in the art will recognize there are other methods of removing coupons from the pipe  100  to form apertures in pipelines that can be used. In an exemplary embodiment, the apertures  110  and  115  are preferably on diametrically opposing sides of the pipe  100 .  
         [0043]     The existence of the apertures  110  and  115  require that, after repair work is completed, a sealing member must be installed across the aperture; otherwise, product can leak from the pipe  100 . In an exemplary embodiment, the completion plug  120  having a rubber O-ring  125  is installed in the stopping fitting  105  to restrict flow of product from the pipe  100 .  
         [0044]     A pig  200  can be inserted into the pipe. Then, the pig  200  can be fed through the pipe  100  via product flow to perform a number of functions, including, but not limited to: cleaning, displacement, batching, and internal pipe inspections. Unfortunately, the pig  200  can be damaged by sharp edges of the apertures  110  and  115 , or can become trapped in/around the apertures  110  and  115 .  
         [0045]      FIG. 2  is a cross-sectional view illustrating the pipe  100  having the pipeline fitting  105  with a piggable plug system  235  inserted in the pipeline  100 , in accordance with an embodiment of the present invention. The plug system  235  includes the plug  130  and retaining assembly  225 . Preferably, the plug system  235  can be inserted into the pipe  100  via the fitting  105  through the aperture  110 .  FIG. 2 , however, illustrates the pipe having two apertures  110  and  115 . Accordingly, the plug system  235  can block both apertures  110  and  115 .  
         [0046]     The retaining assembly  225  of the plug system  235  fits within the fitting  105 . The retaining assembly  225  can include a spring  135 , having a top  135   t  and a bottom  135   b , and a bearing  140 . The spring  135  can be compressed between the completion plug  120  at its top and plug  130  at its bottom to retain the plug  130  in place in the pipe  100 .  
         [0047]      FIG. 15  is a close up illustration of the plug system  235 , showing the retaining system  225  in communication with the plug  130 . The plug  130  can have a round boss  220  at its top, which can be housed by the bottom  135   b  of the spring  135  for the spring positioning and retaining. The compressed spring  135  forces the plug  130  to remain stationary within the pipe  100 . As a result, the spring  135  protects the plug  130  from axial displacement. The bearing  140  can be housed by the top  135   t  of the spring  135 . The bearing  140  reduces friction between the completion plug  120  and the spring  135  during the completion plug installation in the fitting  105 , thus protecting plug  130  from rotation.  
         [0048]     In  FIGS. 3-6 , the plug  130  is illustrated in a close up view. The plug  130  can have a cylindrical portion  145  with the diameter slightly smaller than the diameters of the apertures  110  and  115 . The plug  130  further includes two partial cylindrical portions  150  with the diameter being slightly larger than the diameter of the aperture  110 , which, after plug  130  is inserted in the pipe  100 , can be located above the aperture  110 . The larger cylindrical portions  150  further can have arch-shaped undercuts  160  (see  FIGS. 3 and 4 ), located 180 degrees apart, to aid in plug  130  orientation and stability during and after its insertion in the pipe  100 . Further, the insertable plug  130  includes a circular opening  155 , as illustrating  FIG. 4 , with a diameter approximately the size of the inner diameter of pipe  100 . An axis of the opening  155  is approximately perpendicular to the axis of the cylindrical portions  145  and  150  of the plug  130 .  FIG. 4  also illustrates the location of the cylindrical portions  145  and  150 , and arch-shaped undercuts  160 , in relation to the opening  155 . The arch-shaped undercuts  160  and the large cylindrical portions  150  can be positioned above the opening  155 . A line connecting the centers of the arch-shaped undercuts  160  can be positioned parallel to the axis of the circular opening  155 . After insertion of the plug system  235  in the pipeline  100  (see  FIG. 2 ), the arch-shaped undercuts  160 , interacting with the circumferential outer surface of the pipe  100 , can coincide with the axis of the circular opening  155  and the longitudinal axis of the pipe  100 . As a result, a pig can pass through the fitting  105  along with product flow. An opening  165  at the top of the plug  130  and a threaded hole  170  at its bottom, as shown in  FIGS. 5-6 , can be included to enable connection of the plug  130  insertion and extraction tools.  
         [0049]      FIG. 7  illustrates a vertical cross-sectional view of the pipeline  100  with a fitting  175  having a bottom outlet and a branch  180  connected to this outlet.  FIG. 7  is similar to  FIG. 1 , except a different type of fitting is shown, and the branch  180  is added to the bottom of the pipeline  100 . The aperture  115 , thus, opens to the branch  180 .  
         [0050]      FIG. 8  depicts a vertical cross-sectional view illustrating the pipeline  100  having the bottom outlet fitting  175  installed and the plug system  235  inserted into the pipeline  100 , in accordance with an embodiment of the present invention. As it shown in  FIGS. 9-12 , the plug  130  can include a plurality of slots  190 , which can connect circular opening  165  to an external space surrounding the plug  130  through the top  195  and bottom  205  surfaces of the plug  130 , thus allowing product to flow from the pipe  100  into the branch  180 .  
         [0051]     The plug  130  of the plug system  235  can be fabricated from a wide range of materials such as metals, rubbers, plastics, etc. In an exemplary embodiment, the plug  130  can be fabricated from a material having low mechanical properties. Common law mechanical properties materials that can be used to fabricate the plug  130  include rubber, polyurethane, plastic, and the like. To increase integrity and rigidity of the plug  130  the reinforcing inserts can be placed inside its body.  FIG. 13  illustrates a sectional view of the insertable plug  130  having the reinforcing inserts  210  and  215 , taken from the line A-A in  FIG. 3 .  
         [0052]      FIG. 14  is a close-up of a sectional view from the line C-C in  FIG. 13 , illustrating the reinforcing insert  210  inside the plug  130 . In a preferred embodiment, the inserts  210  and  215  can be positioned perpendicularly to an axis of the opening  155  approximately in its middle reinforcing the plug at its weakest section. One skilled in the art would appreciate that the reinforcing inserts  210  and  215  can be positioned at other locations to aid in reinforcing the plug  130 . One skilled in the art would also appreciate that the material used for the reinforcing insert  210  or  215  can be of the material including reinforcing characteristics for the plug  130 .  
         [0053]     Referring now to  FIG. 20 , a plug system  255  is illustrated for the pipeline  100  having only one aperture  110 . The plug system  255  includes a plug  240  and a retaining assembly  225 .  
         [0054]      FIGS. 16-19  relate to  FIGS. 3-6  illustrating the plug  240  of a plug system  255 , wherein the pipeline  100  includes only one aperture  110 , in accordance with an embodiment of the present invention. Like the plug  130  of the plug system  235 , intended for an insertion in the pipeline having the top  110  and bottom  115  apertures (See  FIGS. 2-6 ), the plug  240  of the plug system  255  can include cylindrical portions  150  with the diameter greater than the diameter of the aperture  110 . Further, like the plug  130 , the plug  240  can include the cylindrical portion  145  with the diameter slightly less than the diameter of the aperture  110 , the arch-shaped undercuts  160 , and the threaded hole  170  for connection of the plug  240  insertion and retracting tools. The plug  240 , however, can include the half-cylindrical opening  245  instead of the full cylindrical opening  155  in the plug  130 . While the plug  130  preferably covers the whole inside circumferential surface of the pipe  100  in an area around the apertures  110  and  115 , the plug  240  need only cover inside surface of the pipe  100 , preferably above the pipe centerline. Moreover, because of these differences in the shapes of the plugs  130  and  240 , the threaded hole  170  for connection of the plug  240  insertion and retracting tools can be located at the top of the plug  240 , more particularly, inside the round boss  220 .  
         [0055]     The assembly of both plug systems  235  and  255 , intended for the insertion in the pipe  100  with one or two apertures can have the same insertion process. The plug  130  or  240  can be assembled with the spring  135  and the bearing  140  outside the fitting  105 . The completion plug  120  with the O-ring  125  can be removed from the fitting  105  (the machines and procedures used for the completion plug removal and re-installation, as well as for the plug system insertion are not discussed in this invention). After this, the plug system  235  can be connected to the insertion tool and inserted into the pipe  100 . Before insertion, the plug system  235  must be oriented relatively the pipe  100  to ensure that the axis of the opening  155  or  245  is parallel to the longitudinal axis of the pipe  100 .  
         [0056]     In summary, the pig  200  placed into the pipe  100  would conventionally catch a corner of the aperture  110  or  115  and cause the pig  200  to clog product flow, and/or damage the pig  200 . The plug systems  235  and  255  enable the pig  200  inserted into the pipeline  100  to flow freely through the fitting  105 , past the apertures  110  and  115 , and eliminate pigging hazards.  
         [0057]     While the invention has been disclosed in its preferred forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made therein without departing from the spirit and scope of the invention and its equivalents, as set forth in the following claims.