Patent Publication Number: US-2018045334-A1

Title: Lead service water pipe line removal apparatus and method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority of U.S. Provisional Application 62/374,828, filed Aug. 12, 2016. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to the field of pipeline replacement and, more particularly, to an apparatus and method for replacing buried drinking water supply lines made of lead piping which minimizes ground disruption and potential dispersion of the lead during pipe removal. 
     It is estimated that there are over 6 million installations of lead pipes carrying drinking water from water supply mains to residences in the United States. Due to the harmful effects of lead ingestion by humans and other animals, replacement of this piping is becoming increasingly imperative. In urban areas where space is tight and buried infrastructure is very dense, excavating buried pipelines for replacement is particularly expensive and not always practical or feasible. 
     Branch water service supply lines are generally less than 2 inches in diameter, with the majority being 1-inch or less. It is common to remove these pipes by accessing and freeing the ends of the pipe, attaching a pulling apparatus to one end, and then pulling the pipe through the ground in which it is buried. Sawing, grinding, and/or fracturing the pipe is not permissible as such operations have the potential to disperse lead particles into the environment. In some instances, replacement pipe will be secured to the end opposite of that being pulled so that the replacement pipe is pulled into position as the old pipe is being removed. Should the pipe being removed break during the pulling process, excavation of the pipe is required which eliminates any advantage of the pull-through replacement method. The risk of breakage when pulling from the leading end or wadding when pulling from the trailing end is greater with lead pipes which are quite malleable and have relatively low tensile strength. 
     An alternative method involves feeding a cable through the pipe to be removed, securing the cable to the pipe, and then pulling the cable and pipe through the ground. While this approach overcomes limitations in the strength of lead pipe, it does not allow for the lead pipe to be easily separated from the cable during the pulling operation. The result is generally that the pulling cable becomes sacrificial, increasing the costs associated with the replacement operation. One such method is disclosed in U.S. Pat. No. 8,277,147 issued to Cilliers which discloses such a method in which the cable is affixed within the pipe by introduction of a settable fluid which secures the cable to the entire wetted length of the pipe interior. 
     It would be advantageous to provide a method of replacing buried lead water supply pipe that overcomes these limitations. 
     SUMMARY OF THE INVENTION 
     The present invention includes an apparatus and a method of replacing buried lead water supply pipe with minimal excavation and which allows removable and containment of the lead pipe. The apparatus includes a leading collet and a lagging collet which are secured to opposite free ends of the lead pipe to be removed. A cable is directed through the pipe to be removed and connected to each of the collets. The cable length should closely match the length of the pipe in which it is directed. The pulling cable preferably extends from leading collet and is connected to a winch or similar pulling apparatus. A connector may be provided on the leading collet to permit attachment of a second cable, such as the cable provided on a winch. The cable between the lead collet and the winch may be directed along a path which permits easy access to the removed lead pipe following extraction from the ground. New pipeline may be connected to the lagging collet so that the replacement pipeline is pulled into the void left by the replaced pipe as it is extracted. 
     A pipeline removal apparatus is provided to connect a winch apparatus to the pipeline pulling cable in a manner that enables the entire length of pipe to be removed from the ground and subsequently removed from the winch apparatus without the need to cut the pipe, eliminating the potential for creating airborne lead particles by having to cut pipe from the removal apparatus as it is removed. To accomplish this objective, a frame with a reaction foot is positioned in the excavated access adjacent to the pipeline, the frame having an adjustable height mast extending therefrom with a guide pulley at a distal end. The pulling cable is directed from a guide pulley adjacent to the reaction foot, around a second guide pulley positioned at the distal end of the mast before connecting to the winch. The length of the cable path around the guide pulleys is at least as much as the length of the pipeline to be removed to avoid entrainment of the extracted pipe in the winch apparatus. Further, the design of the removal apparatus is adjustable to accommodate removal of a range of pipe lengths while providing an apparatus that permits removal of the pulling cable once the pipeline has been extracted from the ground. 
     The method of replacing the pipe comprises the steps of: 
     Accessing the ends of the pipe that is to be replaced. This typically involves excavating the area adjacent to the user valve isolation box and the area where the water supply line enters the building. It is often possible to enlarge a wall penetration surrounding the water supply line to permit the supply line to freely pass therethrough. There may also be a portion of supply pipe extending between the user valve isolation box (typically located at the edge of the right of way surrounding the water main) and the water main. This portion may also be removed using the method, but requires excavation of the water main at the supply line tap location. 
     Providing a pulling apparatus at the leading end of the pipe to be removed. Pulling is typically from the end adjacent to the valve isolation box which provides greater access than locations immediately adjacent to or even within the building supplied by the water supply line. 
     Configuring the pulling apparatus so that a cable connecting a winch to the pipeline is directed along a path that exceeds the length of the pipe to be removed. To this end, the pulling apparatus comprises a frame with a reaction foot that is positioned in an excavation pit adjacent to the pipe, an adjustable mast, and a plurality of guide pulleys to manage the path of the cable. The cable pathway is adjusted so that its length is equal to or greater than the length of the pipeline to be removed. 
     Directing a cable through the pipe to be removed. The cable may be integral to cable provided on the pulling apparatus or a separate cable with provisions for connecting to the pulling apparatus. 
     Attaching a leading collet and a lagging collet to respective ends of the pipe to be removed. The collets are configured to fixedly grasp both the cable and the pipe to be removed. 
     Applying a pulling tension to the cable in the leading direction. The tension is applied to the pipe to be removed at both the leading and lagging collets which prevents the entire pulling tension from being applied to the relatively weaker lead pipe. Continuing to pull the pipeline until it is extracted from the ground and positioned on the pulling apparatus but not enrolled in the winch. 
     Releasing the collets and extracting the cable from within the pipe that was removed. The lead pipe can then be disposed while the pulling apparatus, cable, and collets may be reused. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
         FIG. 1  presents a side view of a typical pipeline replacement arrangement utilizing the method of the present invention; 
         FIG. 2  illustrates one embodiment of a cable connection collet of the present invention shown in a lagging or trailing position; 
         FIG. 3  is a cross-section illustration of the cable connection collet of  FIG. 2  shown in a leading position; 
         FIG. 4  is a section view of the of the cable connection collet of  FIG. 2  taken along cut line  4 - 4 ; 
         FIG. 5  shows a second view of  FIG. 1  wherein the pipeline is partially displaced during removal; 
         FIG. 6  provides side view of a typical water service supply pipeline of the type on which the present invention is useful; 
         FIG. 7  illustrates an alternate means for managing cable and extracted pipe take-up during a removal operation. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art, and they will not therefore be discussed in significant detail. Also, any reference herein to the terms “up” or “down,” or “over” or “under,” or “above” or “below” are used as a matter of mere convenience, and are determined from the perspective of the ground surface. Furthermore, the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application of any element may already be widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. When referring to the figures, like parts are numbered the same in all of the figures. 
     Referring to  FIG. 6 , there is shown a diagrammatic elevation view of a typical arrangement of a buried water service supply line for a building, typically a residence. A water main  19  is typically buried under a street or other right-of-way to provide water to buildings situated therealong. Taps  14  into the water main  19  allow connection of service supply lines comprising an extension line  15  and a service supply line  10 . A service isolation valve  11  is typically provided proximate to the edge of the right-of-way. The service supply line  10  extends through the ground  5  and typically penetrates a building  7 , generally a below-grade wall and features an isolation valve  12 , meter  13 , or other flow managing devices before being distributed to the building interior. 
     For service supply lines comprising lead pipe material, replacement may be accomplished with the instant invention. Referring to  FIGS. 1 and 6 , the service supply line is accessed, preferably by excavating an access pit  18  around the service isolation valve  11 . Once excavated, the valve is removed by shearing the pipe immediately upstream and downstream. An extraction apparatus  30  is positioned in the access pit  18  and the service supply line is disconnected at the building end, typically by shearing the pipe and removing any penetration sealant where the supply line  10  enters the building  7  leaving both ends of the service supply line  10  open. 
     A first cable  32  is directed through the service supply line  10 , the cable having sufficient strength for removing the pipe and having a diameter small enough to fit within the interior diameter of the service supply line  10 . Connecting collets  50  are positioned at each end of the service supply line, one being the leading collet  50   a  and the other being the lagging collet  50   b , determined by the direction in which the supply line  10  is to be pulled. The connecting collets are configured to simultaneously grip the supply line  10  and the first cable  32  to create an integral structure having sufficient tensile strength to withstand the pulling forces. 
     An exemplar connecting collet is illustrated in  FIGS. 2 and 3 , comprising a clamshell or two-part generally cylindrical structure having first and second portions  51   a ,  51   b  that may be clamped simultaneously around the cable  32  and supply line  10 . A first bore  52  is sized to surround the outside diameter of the service supply line  10 . A second bore  54  is sized to surround the outside diameter of the first cable  32 . The first and second bores  52 ,  54  abut at a transition  56  which is positioned to provide sufficient clamping area for the pipe line and the cable to preclude movement. The interior surface of the first and second bores  52 ,  52  is preferably provided with a gripping surface  55  having a high coefficient of friction with the outer surfaces of the pipe line  10  and first cable  32  so that, when clamped, the collets  50  resist movement in relation to the pipe line or cable. As illustrated, the first and second portions  51   a ,  51   b  meet at joining surfaces  58   a ,  58   b  and are clamped together by tensioning fasteners  59 . A small space is preferably provided between the joining surfaces to assure that sufficient clamping force is applied prior to contact between the surfaces. A connector  60  is provided to permit the leading collet  50   a  to be connected to a second cable  33  which provides the extraction force for the pipe line  10 . A similar connector  60  provided on the lagging collet  50   b  enables connection of a pull-through line or even the replacement pipe line itself, the latter having the advantage of removing and replacing the water supply service line in a single pulling operation. 
     The collet configuration as illustrated allows for a single collet configuration to be used in the leading or lagging location simply by reversing the orientation of the collet. Alternatively, the collet configuration may be specific to the leading or lagging position. The configuration further includes tapered portions to ease passage of the lagging collet through the ground. 
     Other configurations of the collets  50  are envisioned that utilize various connections means to pipe line and/or cable. For example, barrel fixtures may be affixed to the cable portions by crimping or equivalent connection, the fixtures having a finite axial length with a diameter exceeding the cable diameter. The fixture outer diameter is sized to permit passage through the inside diameter of the pipe while the transition between cable and fixture provides a stepped shoulder for interface with a matching profile on the inside diameter of the collet normally configured to clamp the cable. The interface limits relative axial movement, whether uni- or bi-directionally, between the cable and collet as would clamping the collet to the cable. Such configurations enabling a fixed connection between pipe line and cable at leading and lagging locations are contemplated within the scope of the invention. 
     Now referring to  FIGS. 1-5 , the cable may be provided with one or more connectors  60  outboard of the pipe line  10  to permit connection of the pipe line  10 /first cable  32  assembly to other assemblies. The leading collet  50   a  is necessarily connected by the second cable  33  to a pulling apparatus  40  such as a winch which provides the tensioning force for pipe line removal. The second cable  33  is directed through an extraction apparatus  30  having a mast  34  and a plurality of pulleys  36   a ,  36   b ,  36   c  or the like to guide the first and second cables  32 ,  33  along with the pipe line  10  surrounding the first cable  32 . The pulleys include at least a first guide pulley  36   a  positioned adjacent to the location at which the buried pipeline is exposed in the access pit and a second guide pulley  36   b  positioned at the distal end of the mast  34 . Additional pulleys  36   c  may be provided to guide the cables. 
     The mast extends generally orthogonally away from the axis of the pipe line  10 , preferably upwardly out of the excavated access pit, and is of sufficient height as to provide a take-up length that enables the length of the pipe line  10  to be removed to be fully supported on the mast without the pipe line  10  being engaged in the pulling apparatus  40  (e.g., winch). This generally requires that the mast  34  be at least approximately half the height as the length of pipe line  10  being removed. In this configuration, the extracted pipe is deflected around the first and second guide pulleys. It may be preferable for the mast length to be at least that of the pipe to be removed so that the extracted pipe is only deflected around the only the first guide pulley  36   a  adjacent to the buried pipeline end which eases removal of the first cable  32  therefrom once the pipe is fully extracted from the ground. 
     Removal of buried pipe line by pulling methods is best accomplished in a single, continuous pull; interruptions of the pulling increase the chances of breaking the pipe line and increase wear and tear on the cables and cable tensioning apparatus. 
     The mast  34  may be provided with adjustment provisions to enable the height of the mast (take-up length) to be altered to suit the specific pipe line removal configuration of different removal locations. The adjustment provisions may comprise mechanical connections  39  which allow extension sections  34   b  to be added between the base portion  34   a  and the distal portion  34   c  to achieve the required take-uplength. Extension sections  34   b  may be provided in various lengths to enable a single additional section  34   b  to be used, or extension sections  34   b  having a uniform length may be provided and the proper number of extension sections  34   b  incorporated to yield the desired mast height (take-up length). The mechanical connections  39  are preferably uniform in configuration and may include a flanged connection using uniformly spaced bolted connections. 
     The mast  34  may also include articulated joints that enable the mast to be conveniently compacted for transport when not in use. Such articulated joints may also be used to adjust the mast height to achieve the desired offset of the second guide pulley to achieve the require cable take-up length. 
     Other mast configurations are also possible.  FIG. 7  illustrates one such alternative in which a pulling apparatus  40  is not available. The mast  34  may comprise telescoping sections  341 ,  342  with a hydraulic cylinder  345  or the like to selectively extend the telescoping sections. The second cable  33  is connected at one end to a fixed structure (shown as the base of the extraction apparatus in the figure). Tension is generated by extending the telescoping member. The cable connection may include provisions to adjust the cable anchorage and a take-up apparatus provided to increase the length of pipe than may be removed with the assembly. One disadvantage of this arrangement is a limited amount of extension and thus pipe line movement that may be achieved in a single stroke. The cable connection may include provisions to adjust the cable anchorage and a take-up apparatus provided to increase the length of pipe than may be removed with the assembly, though this configuration is inherently limited by the amount of extracted lead pipe that may be held on the apparatus and the need to remove extracted lead pipe therefrom. The advantage is a more compact footprint for the extraction apparatus which may work well when short service supply line lengths are involved. 
     The extraction apparatus  30  further comprises lateral and vertical reaction blocks  35 ,  37  to withstand the reaction forces of the second cable  33 , which may be on the order of 4,000 to 10,000 lbf. 
     Once the pipe line  10  is extracted from the ground  5  and preferable supported on the extraction apparatus, the collets  50  and the interior (first) cable  32  are removed from the extracted pipe line  10 . The pipe line  10  may then be contained and scrapped while the cable and collets are available for reuse. Once the first cable  32  is removed, the pipe line  10  may be cut by shearing into easily manageable length for disposal or recycling. The requirement to cut lead pipe by shearing instead of cutting or fracturing requires that any inserted material be removed prior to shearing. Otherwise such materials must be scrapped along with the extracted pipe line. 
     Removal of the extension line  15  between the main  19  and the service isolation valve  11  may be easily accomplished by realigning the extraction apparatus and directing the first cable  32  through the extension line  15 . Most lead removal and replacement efforts involved excavation of the service main thereby facilitating assess to the distal end of the extension line adjacent to the tap  14 . 
     It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention.