Abstract:
An apparatus and method for inserting a new service pipe into an existing high pressure service pipe that contains a leak, without the necessity of excavation or separately shutting off the supply of the high pressure gas upstream of the effected pipe section. A nosecone coupled with a unique stopper assembly allows a temporary sealing of the high pressure pipe between the main and the leak point, and insertion flow of a sealer through the nosecone, such that the sealer fills the annular space between the new pipe and the old pipe, providing a gas tight permanent seal. The end of the stopper assembly has temporary stop plug that must be drilled open to reestablish the communication of high pressure gas into the new pipe without the chance of flow entering the old pipe.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the repair of high pressure gas or water service pipes which contain a section(s) of leaking or deteriorated pipeline. More particularly, the present invention concerns the insertion of a unique stopper assembly for discontinuing or sealing the flow of the high pressure service into the old section of the high pressure service pipe to be repaired. The stopper assembly further facilitates the insertion of a new, or replacement service pipe within the leaking or deteriorated section, and the pumping of a sealant between the old pipeline and the newly-inserted pipeline. The sealing aspect of the stopper assembly is operated or controlled by a tool means also inserted through the high pressure service pipe, and internally of the stopper assembly. The invention also facilitates pressure testing of the sealed pipeline section prior to returning the high pressure service. 
     2. Discussion of the Prior Art 
     Previous servicing and/or replacement of underground high pressure service pipes typically involved excavation of areas adjacent the affected pipe and temporary termination of the flow of gas, either at the point of leakage or at a valve location upstream of the leakage, usually at the connection with the main. Past methods proved to be time consuming and costly, thus it could be appreciated that an alternative method was sought where the replacement of the leaking or deteriorated section could be performed without the need for excavation. 
     Early improvements involved the insertion of a new pipe section into the old pipe section without the need for excavating, but those early attempts failed to solve higher pressure system sealing. Very early methods involved pumping sealant in between the pipes without the ability to visually confirm a complete filling of the void between the old and new pipes. 
     Furthermore, prior systems failed to provide a method for pressure testing the repaired section at the seal point before returning the section to service. As these systems typically required the use of a temporary plug in the sealing process wherein the plug was merely removed after sealing stage was completed. 
     A much more sophisticated service pipe insertion apparatus and method is described in pending U.S. application Ser. No. 08/811,521, to the present inventor. That device solves some of the problems described immediately above, but is limited to use in very low pressure gas systems which are typically held at about six inches of water column pressure. That device provided a hollow nosecone assembly for receiving on one end thereof, the new pipe to be inserted within the deteriorated or leaking old pipe. The nosecone assembly and the new piping was typically fed from the gas meter end, upstream towards the gas main, with the nosecone proper being disposed between the main and the leak. The nosecone assembly included a removable plug that interconnected with the nosecone proper on one end thereof and which received a sealant supply tube on the other end thereof. The sealant supply tube was concentrically received within the newly provided service piping, and thus extended co-extensively to the same location where the new service pipe was inserted (gas meter). At the meter location, a sealant is initially pumped through the sealant tubing, eventually exiting at the end of the plug which was inserted into the nosecone proper. Sealant exit points on the nosecone proper communicate the sealant from the removable plug to the volume of area existing between the old piping and the newly inserted piping. The sealant then reverses its flow direction so that all entrapped air is purged from the volume between pipes, until the sealant again returns to the inlet pumping location. In this way, the entire section of piping from the meter to the nosecone assembly is purged of air and completely sealed. The procedure required a lengthy sealant cure time to pass before continuing, a cured-in-place seal being effected within the nosecone. The removable plug and sealant tubing, being concentrically inserted within the new service piping, is then removed thus re-establishing gas flow from the live side of the assembly into the newly inserted service piping. 
     The apparatus and method of the present invention on the other hand comprises a modification of the device and method described in U.S. Ser. No. 08/811,521 by providing novel stopping or sealing means for terminating the flow of a higher pressure gas service. Unlike the earlier device which used fins with sealant backing to seal the gas, the device of the present invention utilizes a stopper assembly for creating a two-point sealing of the service line. The apparatus of the present invention also introduces a unique sealant introduction means and methodology for feeding the sealant in between the gap which exists between the old and the new pipes. The present apparatus also provides for pressure testing the system at the seal point, purging air from the system. The present invention does not have a cure time waiting period once the trap door is closed. 
     SUMMARY OF THE INVENTION 
     The present invention involves a service line pipe repair assembly for use in a high pressure piping system whereby a new pipeline is inserted into an old pipeline from a gas receiving-destination point, such as the area of a gas meter, without the need to excavate. The apparatus is inserted through the old pipe to a point known to be upstream of the leaking or deteriorated area, and in extreme cases, the insertion may extend the entire length of the old gas service pipe, namely from the meter to the gas supply main. Contiguous with the new pipe is a stopper assembly which forms a seal between the old and the new pipe, thereby terminating live gas service. 
     The unique stopper assembly effects a seal through internal manipulation of a section thereof, which causes a compression sleeve and nut to compress a pair of spaced elastomeric sleeves. The compression of the sleeves creates a ballooning effect on each sleeve, which in turn seals the area between the apparatus and the old pipe, thereby stopping gas flow. The expanded sleeves undergo a pressure test by means of introducing nitrogen through a weep hole located at the point of seal. Then, a removable plug and sealant tubing, which also forms part of the apparatus, is then inserted into the new service piping, whereby a sealant is introduced into the sealant tubing, to the point where a secondary seal is established. A sealant introduction means allows the sealant to be discharged from the sealant tubing through a series of exit points in the introduction means. Since the stopper assembly is sealing the line service pipe immediately ahead or upstream of the apparatus, the sealant is forced to change direction and travel backwards, but only through the annular space existing between the old pipe and the new pipe. The sealant then discharges near the sealant&#39;s point of entry, thereby allowing visual observation and confirmation that the annular space is completely sealed and that all air is purged out of the air space volume existing between the old and new pipes. Thereafter, the sealant tubing and the plug are withdrawn from within the new piping. Pressure testing ensures that the pipe replacement procedure has been successfully performed. A drilling tool is then inserted through the new piping until the drilling tool encounters a pressure disk/stop flange, which is incorporated into the distal end of the stopper assembly. The destructive drilling of the disk/plug opens the flow of high pressure gas to an internal passageway, common within the entire stopper assembly, and since that same passageway is in fluid communication with a coextensive internal passageway of the new piping, high pressure flow is reestablished. The drilling tool is then removed from the new piping and the new piping is then reconnected to the gas meter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following description of the invention will be better understood by reference to the accompanying drawings, wherein: 
     FIG. 1 is a schematic view highlighting the present invention as inserted within a section of pipe that is leaking or deteriorated; 
     FIG. 2A is a cross-sectional view of the present invention; 
     FIG. 2B is an enlarged partially exploded cross-sectional view of the invention shown in FIG. 2A; 
     FIG. 2C is a cross-sectional view taken along line  2 C— 2 C of FIG. 2B, emphasizing the location of the sealant exit ports; 
     FIG. 3A is a cross-sectional view of the compression portion of the sealing means; 
     FIG. 3B is an end view of the nosecone receiving end of the compression assembly; 
     FIG. 4 is a side view of the stopper assembly of the sealing means; 
     FIG. 5 is a cross-sectional view of a retention collar shown in FIG. 4; 
     FIG. 6 is a cross-sectional view of one-half of the split-collar shown in FIG. 4; 
     FIG. 7 is a cross-sectional view of the nosecone assembly; 
     FIG. 8 is an alternative embodiment of a nosecone assembly; 
     FIG. 9 is a partial cross-sectional view of the removable sealant assembly; 
     FIG. 10 is a cross-sectional view of the sealant introduction means in a closed position; 
     FIG. 11A is a cross-sectional view of the sealant introduction means of FIG. 10 showing the removable sealant assembly feeding sealant between the old and new piping; and 
     FIG. 11B is a cross-sectional view taken along line  11 B— 11 B of FIG.  10 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning attention now to FIG. 1, the concept of the present invention will now be generally described. FIG. 1 shows in a schematic cross section, a portion of an old, leaking or deteriorated pipe  20 , that is being fed high pressure fluid from an upstream gas main  25 . The fluid being fed can be natural gas, propane, or water, etc., although in the context of describing the invention, it will be assured that a gas is being fed through the pipeline. The flow of gas is represented by the heavy arrows designated as  21 , which flows from the main towards meter  27 . A leak designated at  23  can represent a single gas exit point through old pipe  20 , or it can represent a section of deteriorated piping which needs replacement from leak point  23 , back to meter  27 . 
     In order to avoid excavating the area surrounding leak  23  or shut-off tee  19 , the apparatus  30  of the present invention is inserted into old pipe  20  once it has been disconnected at an appropriate above-ground location, usually at inlet valve  26  to meter  27 . A gland arrangement which is well known to those in the art, is attached to the old piping at the disconnect point temporarily sealing the out-rush of the high pressure fluid. The gland arrangement also facilitates the insertion of the apparatus of the invention into the old pipeline so that the apparatus can be inserted beyond leak  23 . Those in the art know how to detect the apparatus respective leak  23  without being able to actually see the apparatus during insertion. It is obvious that the apparatus must be located upstream of leak  23 , towards gas main  25  in order to prevent gas flow through leak  23 . 
     The apparatus of the invention as shown in FIG. 1 generally includes a sealing means (not shown) for creating a seal within piping  20 , thereby terminating the gas flow  21  to leak  23 , and means for retaining thereon (not shown) a new provision of piping  15 , which replaces the old piping. Those elements will be explained in greater detail below, but it is important to understand that all components comprising the invention will have a respective centrally located, axially disposed passageway which forms a continuous passageway through the apparatus. As will also be explained later, a removable sealant assembly is inserted into new piping  15  after the gas flow is terminated in order to facilitate sealing the volume of annular space  17  existing between the old and new piping  20  and  15 . The area being sealed generally extends from apparatus  30 , backwards, all the way to gas meter  27 , once a sealant is pumped therebetween. 
     Referring now to FIGS. 2-4, the sealing means  40  of the present invention will now be explained in greater detail. The sealing means  40  of the present invention serves two purposes. First, it functions to terminate the flow of high pressure gas traveling towards the leak or deteriorated piping, and secondly, it serves as a means for later reestablishing gas service once the new pipeline has been installed, sealed, and pressure tested. A related aspect of the sealing means is to facilitate the sealing of the annular space between the old and new piping, as well as pressure testing, as will be explained later. In FIG. 2A, the sealing means  40  is generally shown with respect to the entire apparatus of the invention being inserted within the deteriorated pipeline  20  at a desired location, while FIG. 2B shows the invention in larger scale. FIG. 3A illustrates a first portion  40 A of the sealing means, which will also be referred to hereinafter as the compression assembly. The compression assembly is comprised of a compression nut  42  attached to a compression sleeve  50 , which in turn receives a nosecone assembly  60 . 
     The compression nut  42  has a generally cylindrically shaped body which has a proximal end  42 A and a distal end  42 B and the axially disposed, centrally located passageway  45  extending completely through the compression nut  42 . At the distal end  42 B, the central passageway is partially provided with internal threads  47 , extending from end face  48 B, inwardly of passageway  45 , towards end face  48 A. The external surface  46  of compression nut body  42  is also partially threaded on the same end  42 B, wherein external threads  43  originate from end face  48 B and extend towards end  42 A, terminating at shoulder  44 . As FIG. 3A illustrates, external threads  43  of compression nut body  42  threadingly engage a complementary set of threads  57  formed internally of end  50 A on compression sleeve  50 . 
     Compression sleeve  50  is threadingly coupled with nut  42  through the thread pair  43 ,  57 , which are reverse, or left hand threads, rather than standard right hand threads. The importance of using reverse threads will be understood later when the operation of the sealing means is provided. Sleeve  50  is threaded onto nut  42  until end face  58 A abuts shoulder  44  of compression nut  42 , whereby distal end face  48 B also engages shoulder  59  which is formed at the terminal end of internal threads  57 . It is of consideration to realize that the central passageways  45 ,  55  of each member  42 ,  50  are coextensive and continuous when said members are coupled, as are outside surfaces  46  and  56 . 
     On the opposite end  50 B of sleeve  50 , a stub  52  projects outwardly from terminal end face  58 B and is provided with external threads  53  for receiving thereon, nosecone assembly  60 . The external threads  53  extend from terminal end face  58 B to end face  51  on stub  52 . The end face  58 B also defines a shoulder for receiving thereon, nosecone assembly  60 . When nosecone assembly  60  is threadingly mated to stub  52 , nosecone base surface  66  abuts end face  58 B, wherein outside surfaces  63  and  56  coextensively align together. 
     Turning attention now to FIG. 7, the preferred nosecone assembly  60  will now be described in greater detail. As seen, the assembly is comprised of end cap  62  and an insertable plastic pressure disk  68 . The end cap  62  includes a tip  62 A and a base end  62 B, and an axially disposed, centrally located passageway  65  extending therebetween. Internally of said cap, a portion of the passageway is threaded, namely from base end surface  66  to shoulder  64 . The shoulder is of a width or extent that can receive thereon, the pressure disk  68 . Once received, threads  67  of end cap  62  are threadingly engaged with external threads  53  on stub  52  until end surface  66  abuts terminal end face  58 B on compression sleeve  50 . During tightening of end cap  62 , the pressure disk is tightly compressed between the surfaces  64 A,  64 B defining shoulder  64 , and end face  51  of stub  52 . The disk undergoes plastic deformation such that necked down portions of disk  68  form a gas-tight seal between the above-mentioned surfaces. More importantly, plastic pressure disk  68  seals the end face  51  of stub  52  from the high pressure gas service which exists within passageway  65  on the tip end side of pressure disk  68  prior to sealing. FIG. 3B shows the construction of end face  51  of stub  52 , and it is seen that stub  52  is provided with hexagonally shaped port  54  that is axially disposed, centrally of the stub, and is defined by the surfaces  54 A. By sealing this port  54 , high pressure gas is prevented from entering the internal passageways  55  and  45  of the compression assembly through passageway  65 , and this is very important to the operation of the sealing means, as will be fully understood once the second portion of the sealing means is described. The significance of providing an hexagonally-shaped port is operationally tied to a complementary shape of a tightening tool (not shown) that interfaces within port  54 , the tool used for effecting the operation of the sealing means of the invention. 
     An alternative type of nosecone assembly is envisioned and is illustrated in FIG.  8 . Like the assembly shown in FIG. 7, it includes an end cap  225 , that is provided with internal central passageway  227  which is provided with a first set of threads  229 , and a second set of threads  231 . The assembly also includes a solid, plastic plug  233  which has complementary threads for engaging threads  231  to thereby seal passageway  227  when mated. The end cap  225  is threaded by threads  229  to threads  53  of stub  52 , until end face  224  abuts end face  58 B. Like disk  68 , the plastic plug prevents high pressure gas from entering internal passageways  55  and  45  of the compression assembly. 
     Turning attention now to FIG.  2 A and FIG. 4, the second portion  40 B of the sealing means will now be described. The second portion of the sealing means is referred to herein as the stopper assembly and it is comprised of a hollow shaft  70  which receives thereon, a pair of spaced, distendable elastomeric members which seal the annular space  17  existing between old pipeline  20  and the apparatus of the invention. The shaft is provided with an axially disposed, centrally located passageway  75  which extends the entire extent of shaft  70 , between proximal end  70 A and distal end  70 B. As seen, ends  70 A and  70 B are each provided with threads  72 A,  72 B. Threads  72 B threadingly mate with internal threads  47  of compression nut  40 . When assembled as such, internal passageway  75  is in communication with internal passageway  45  and  55  of the compression assembly. 
     The first and second distendable elastomeric membranes  80  and  90 , are laterally spaced from each other by split collar  110  and are braced on each respective end by end collars  100 A and  100 B. The end collars  100 A and  100 B are identical in all aspects, therefore, only one member will be described in detail although it should be understood that both end collars function exactly the same, as will now be described. Generally, each end collar will be referenced as member  100 . 
     FIG. 5 shows one of the end collars  100  in cross-section, and it is provided with an axially disposed, centrally located throughbore  105  deliminted by internal surface  107 . Each of the end collars  100  is frictionally slid over outside surfaces  76  of shaft  70 , necessarily dictating that throughbore  105  is preferably of an inside diameter that is closely matched to the outside diameter of shaft  70  so as to avoid oscillating movement of the collars along shaft  70 . Also seen is the large undercut  108  formed in front face  102  for receiving one of the end faces  82 ,  84  or  92 ,  94  of either of the elastomeric distendable members. Each of the surfaces  108 A and  108 B which define undercut  108 , hold and restrain the end face of the distendable member during operation of the sealing means and prevents the ends of members  80 ,  90  from riding over the outside surface  101  of each end collar. That functional aspect of undercut  108  will become clearer during the operational description of the sealing means, which follows below. The second end face  104  of collar  100  is provided with a second and relatively smaller undercut  106  for receiving therein an O-ring (not shown), which creates a seal between the end collars  100  and outside surface  76  of shaft  70  when each of the collars are slid onto shaft  70 . 
     Turning to FIG. 6, one-half of the split-collar  110  is shown in detail from the pair first shown in FIG.  4 . Since each half  110 A and  110 B are mirror images of the other, only one-half will be described in detail although like character numbers will apply to both halves. 
     The half collar  110 A is provided with an axially disposed, centrally located throughbore  115  that is delimited by inside surface  122  which contacts outside surface  76  when frictionally slid onto shaft  70 . The outside face  112  is provided with annular undercut  116 , which is defined by base surface  118  and wall surface  120 . Similar in purpose to the annular undercuts provided in the end collars, undercut  116  holds and prevents an end face from each of the distendable members from sliding over and onto the outside surface  111  during operation. The opposite and inside face  114  of each split collar  110  is provided with a radially disposed channel  124  that extends perpendicular to throughbore  115  between surfaces  122  and  111 . When each half collar is assembled together, the respective channels  124  on each half collar, forms a full weep hole  125 , but it should be understood that the weep hole  125  does not extend through the entire split-collar; it only exists on half of the collar. Referring now to FIG. 2B, it is seen that weep hole  125  is in communication with radial hole  78  of shaft  70 , which in turn is in communication with internal, central passageway  75 . The weep holes  125  and  78  are provided in the apparatus of the invention for pressure testing purposes, and those tests will be explained as part of the operation of the invention, which follows later. 
     Turning now to FIGS. 2A,  2 B,  10 , and  11 A, the sealant introduction means and the receiving and retaining means will now be explained in greater detail. As FIG. 2A generally shows, the means for receiving and retaining the new pipeline  15  that is to be inserted within the interior of the old pipeline is illustrated at  130 . More specifically, FIGS. 2B,  10  and  11 A show the receiving and retaining means is comprised of coupling housing  132  having a top and a bottom end  132 A,  132 B, with the top end further including a projecting arm  134  which has an outside surface  136  formed as barbs  137  for frictionally receiving thereon the end of a new pipeline  15 . FIG. 11A shows arm  134  receiving the interior of new piping  15 , with annular swaging member  140  ensuring that pipeline  15  is retained on housing  132 , although once new pipeline  15  is inserted over barbs  137 , it usually is not necessary to provide swaging member  140 . The other end is shown here as having threads  138  formed on part of the housing outside surface, for insertion into the means for providing sealant. In another embodiment of the receiving/retaining means, it is envisioned that bottom end  132 B not have the outside threads, but rather be formed with inside threads generally in the same location as those shown. In that way, if circumstances are such that the sealant material will not be used to seal the annular space  17 , the receiving/retaining means can be threadably connected directly to the threads  72 A formed on proximal end  70 A of shaft  70 . In that way, the sealing means can still be used to terminate gas flow into the old, leaking section of pipeline, while simultaneously providing the new pipeline as the replacement for the old service line. Since the sealing means is never removed from the pipeline, the new pipeline attached to it through the receiving/retaining means, will be automatically established. However, those circumstances where a sealant material will not be provided are extraordinary, and therefore the embodiment as shown in FIG. 11 will be preferred. 
     As FIG. 2A illustrates, the receiving and retaining means  130  is threadingly connected to a first component of the sealant introduction means referred to as the sealant dispersion receptacle  150 . Also shown is a second component  170 , connected to the first component, and finally, the figure illustrates a third component  240 , a removable sealant supply assembly ready to be inserted wholly or partially within the first and second components. In the blown-up illustration of FIG. 2B, only the first and second components will be described in greater detail. 
     The first component  150  is comprised of the sealant dispersion receptacle and it corresponds to an outside container which has an inside end  150 A and an outside end  150 B, and includes an axially aligned, centrally disposed passageway  155  extending therebetween. At the midsection  150 C of receptacle  150 , there exist radially oriented ports  152  extending from central passageway  155  to outside surface  158 . As FIG. 2C shows, there are at least three ports  152  formed at 120° intervals from each other. The number of ports can be increased to four, but it is not envisioned that more than that be provided since there is a balance between providing enough ports to expediently allow the flow of a sealant material therethrough, versus the possibility of these ports creating a possible leak location during pressure testing. This tradeoff will be understood once operation of the invention is described. 
     Internally provided within receptacle  150  are two annular grooves  154  and  156 , axially displaced from each other and equally spaced from midpoint  150 C. The groove  156  is the delimiting end of internal threads  160  formed inside passageway  155  at end  150 B. The opposite end  150 A also is provided with internal threads  162  along passageway  155 , however these threads do not continue to the annular groove  154 , but rather terminate at and form the shoulder  164 . The shoulder  164  abuttingly receives end face  176  of the second component when portions  150  and  170  are connected together by threadingly joining threads  172  with threads  162 . The annular grooves  154  and  156  receive O-rings therein which are inserted from respective ends  150 A,  150 B prior to connection of component  150  to  170 . The O-rings which are inserted into grooves  154  and  156  are of the same diameter and thickness, and form a contact seal with a valve gate which controls the flow of sealant through ports  152  when the sealing function is performed, as will be understood shortly. 
     When receiving/retaining means  130  is threadingly connected to receptacle  150  by threading threads  138  into threads  160 , the central passageway  155  of sealant dispersion receptacle  150  is in communication with the central passageway  135  of the receiving and retaining means  130 , and outside surface  142  is coextensive with outside surface  158  after shoulder  140  abuts against end face  168 . 
     Another portion of the sealant introduction means is inner receiver housing  170 . Like the outside container portion, the inside container portion  170  has an inside end  170 A, and outside end  170 B, and an outside surface  178 . Internally of receiver housing  170 , there is a chamber  180  defined by a bore of diameter d 1 , which extends between end face  176  and ledge  182 . There is also an axially aligned, centrally disposed passageway  175  extending between end face  188  and chamber  180 ; passageway  175  and chamber  180  are in communication with each other. The inside end  170 A of passageway  175  is internally provided with threads  186  which extend between end face  188  and internal shoulder  184 . 
     The passageway  175  has a relatively smaller diameter d 2  compared to diameter d 1  of chamber  180 . As mentioned above, external shoulder  174  abuts internal shoulder  164  of sealant dispersion receptacle  150  when threads  172  are threadingly mated together with threads  162 . 
     The chamber  180  of receiver housing  170  receives therein a compression spring  190 , as best seen from viewing FIG. 10. A bottom  192  of spring  190  rests on internal ledge  182 , while top  194  abuts against a flange  202  of valve gate  200 . The valve gate is formed from a hollow piece of tubing, and the bottom end  200 A is flarred outwardly to form flange  202 . The combination of spring  190  and valve gate  200  forms the sealant flow control valve, which controls the introduction of a sealant material into air space  17  between the old and new pipelines. 
     In a normal resting position, the sealant control valve closes radial ports  152  in the sealant dispersion receptacle, where outside surface  204  is in very close approximation with the wall surface defining internal passageway  155  to effectively seal ports  152 . As a back-up system, the O-rings  210  frictionally contact outside surface  204  and fluidly seal each end of the valve gate. 
     Turning attention to FIG. 11A, the sealant control valve is seen in a compressed position, wherein the compression spring  190  is fully compressed and the position of valve gate  200  has been moved leftward in the figure, such that the left-most O-ring within groove  154 , still contacts against outside surface  204 , thereby creating a fluid seal at that point of contact. 
     FIG. 11A also shows that compression of spring  190  is the result of the third member of the sealant introduction means, the removable sealant assembly  240 , which was initially introduced in FIG.  2 A. As FIG. 2A shows, the removable sealant assembly  240  is inserted into new pipeline  15 , and because the respective central passageways  135 ,  155  and  175  are all in axial communication, the assembly  240  is readily inserted and axially slid from the terminal end of the apparatus, towards the proximate end thereof, eventually contacting the gate  200  of the sealant control valve. 
     The removable sealant assembly  240  is comprised of two pieces, namely a cylindrical plug  250  and a sealant supply tubing  260  attached to the plug, each of which is illustrated in FIGS. 2A,  9 , and in an exploded position in FIG.  2 A. The cylindrical plug  250  has an axially disposed, centrally located blind bore  255  therein which extends from that end  251 , towards end  253 , for communicating a sealant material therethrough, with the sealant eventually being forced out of the plurality of radially disposed holes  256  in fluid communication with blind bore  255 . As seen in FIG. 9, sealant supply tubing  260  is comprised of an elastomeric or plastic material having a first, open end attached to a second end  253  of plug  250  by sliding the inside surface  262  of the tubing over serrated edges  258 . The outside surface  266  of tubing  260  and outside surface  252  of plug  250  are coextensive when assembled so that sealant assembly  240  does not catch on any of the internal surfaces of the retaining means and sealant introduction means, as will become evident as the sealing process is explained below. 
     The operation of the invention will now be described with respect to replacing an old, deteriorated section of piping with a new section, sealing the air volume between the sections, and then pressure testing the system before returning gas service. 
     First turning to FIGS. 1 and 2A, the initial step begins with insertion of the apparatus of the invention  30  into the old pipeline  20  from a disconnect point at the gas meter  27 . A gland arrangement (not shown) is attached to the open end of the old pipeline just prior to insertion, and it temporarily stops the flow of escaping gas. It also facilitates feeding the apparatus to a point beyond the leak  23 , keeping in mind that the new piping  15  is attached to the apparatus such that as the apparatus is fed inwardly, new piping is simultaneously being fed inwardly too. 
     Once at the desired location, a tightening tool is then fed through the new pipeline  15 , and into the body of the apparatus of the invention. Because the receiving and returning means, the sealant introduction means, and the sealing means all have a coextensive, axially arranged, central passageway extending communicatively together, the tightening tool is readily fed internally into engagement with stub  52 , which is provided with the hexagonally-shaped port  54  centered therein. The tool likewise has a hexagonally-shaped head, which mates within port  54 . The length of the tool head is predetermined so as to extend the entire length of the port once inside. Proper alignment and insertion between the hexagonal port and the tool head is easily determined by an operator at the meter end of the new pipeline. An operator of the tool will feel the feed of the tool stop, since the tool head initially stops against internal face  51 C. Upon slow rotation of the tool, he can then feel the hexagonal tool tip enter the port  54 , since the feed of the tool will again continue in the feed direction, but ever so slightly. 
     Assuming now that the tool head is fully inserted within the port  54 , an operator will further manipulate the tool by rotating it in a counter-clockwise direction. Since the compression nut  42  and compression sleeve  50  are fastened together in a face-to-face relationship (end face  58 A engaging shoulder  44 ), these components will be rotated in unison in a counter-clockwise direction. As FIGS. 2B and 4 illustrate, threads  72 B of shaft  70  receive and mate with threads  47  of compression nut  42 . Since the reverse thread action of threads  57  and  43  keep the compression sleeve and nut together as one operating unit, the effect of reverse thread pairs  47  and  72 B is to move the compression assembly in a direction towards distendable members  80 ,  90 . Since members  80 ,  90  are held between end collars  100  and split-collar  110 , and since these members are slidably resting on outside surface  76  of shaft  70 , they also will move in the same direction as the compression assembly. However, since the sealant introduction means  150 ,  170  and the retaining and retention means  130  are effectively fastened to end  70 A of shaft  70  through threading engagement with standard threads  72 A, those components act as a stop against the further sliding of members  80 ,  90 ,  100  and  110 . Continued movement of the compression assembly causes deformation of distendable members  80 ,  90 , such that each member forms into the double-humped configuration seen in FIG.  4 . Each member forms a gas-tight seal  86 A,  86 B,  96 A,  96 B where each respective outer surface  86 ,  96  contacts inside pipe surface  20 A of old pipeline  20 . Although FIG. 4 slightly exaggerates the distances between surfaces  86 ,  96  and surface  20 A when in their initial state, the travel provided on threads  72 B is predetermined to ensure that each distendable member  80  and  90  will form the double seals  86 A,  86 B,  96 A,  96 B on each member. Amazingly, the provision of undercuts  108  with each end collar  100 A,  100 B and with split-collar  110  contributes to the formation of the symmetrically-shaped double humps on each member  80 ,  90 . Because the undercuts securely hold the respective end faces  82 ,  84  and  92 ,  94  of each member within the respective collars, and preventing the end faces from overriding onto the outside surfaces  101 A,  101 B and  111  of the respective collars, a uniform compression of each distendable member occurs, leading to the double humped configuration. 
     The next operational step in utilizing the present invention is to ensure that a gas-tight seal is in fact being made at sealing points  86 A,  86 B,  96 A,  96 B. This is done by first removing the tool from within new pipeline  15  and then introducing pressurized air into the new pipeline and into the central passageway of the apparatus, such that the pressurized air exits radial weep hole  125  in split-collar  110 . It should be appreciated from viewing FIG. 4 that it is the air volume of the space existing between the leftmost seal points  86 A,  86 B and the rightmost seal points  96 A,  96 B that is pressurized to a level higher than the line pressure of the gas service. Typically, air at 90 psig is introduced and then held for a period of at least 15 minutes, during which time, a drop in pressure would indicate that either of the distendable members is not sealing. If the leftmost seal was failing, the pressure gauge would drift downwardly until the service line pressure is reached and then an operator would be able to detect the smell of natural gas at the header arrangement used for introducing the pressurized air. If the rightmost seal was leaking, the operator would again notice the gauge pressure falling. This time however, he would not detect the smell of gas at the introduction header during complete bleed down of the new pipeline. 
     If a gas-tight seal is obtained, then the gauge pressure will remain steady during the entire test period. If it does not, the tool used for effecting the seal can be reintroduced into the hexagonally-shaped port  54 , in order to loosen the apparatus and move it to a second location where the seal can again be re-established. 
     Once a gas-tight seal is established, the old pipeline is now temporarily sealed off from the gas main. The next step is to then simultaneously purge all entrapped air from between the old and new pipelines, and to fill the area between said pipelines with a quick-set sealant material. Turning now to FIGS. 2A,  10 ,  11 A and  11 B, the sealant introduction aspect of the invention will now be described. 
     In FIG. 2A, it is seen that component  240 , referred to earlier herein as the removable sealant assembly, is insertable within the new pipeline  15 . This assembly is fed from the same location where the new pipeline was inserted into the old pipeline. This removable assembly will be used to uniquely introduce the sealant material that will fill the void between the old and new pipelines, thereby providing a final means for ensuring that gas will not leak through the deteriorated pipeline once gas service is re-established. 
     Referring now to FIG. 10, it is seen that the removable sealant assembly has not yet been introduced into the sealant introduction means. From this figure, it is important to realize that the radial ports  152  of the sealant dispersion receptacle are closed and sealed by the spring-biased gate  200  of the sealant flow control valve, thereby preventing the establishment of a fluid communication between the annular space  17 , the internal passageway of apparatus  30 , and of course, the internal cavity of the pipeline  15 . In order to create such communicative pathway, the bias of spring  190  must be overcome so as to move valve gate  200  in a leftward direction in the figure, to a point where gate  200  is no longer covering the ports  152 . In FIG. 11, it is seen that the removable sealant assembly is inserted within the receiving and retaining means  130  and the sealant introduction means, specifically into the sealant dispersion receptacle  150 . An operator uses the sealant assembly  240  as the means for biasing spring  190  into a fully compressed state, thereby moving valve gate  200  leftward into internal chamber  180  of receiver housing  170  so as to open radial ports  152  relative to valve gate  200 . The full compression of spring  190  is realized when feeding of the sealant tubing of the removable sealant assembly stops its further inward progression. 
     It is also seen that cylindrical plug  150  is now disposed within central passageway  155  and in contact with both of the O-rings so as to create internal seals which will prevent sealant material from traveling anywhere but through exit ports  152 . The full compression of spring  190  leaves radially displaced holes  256  of plug  250  in alignment with radial ports  152 . The compressed spring height, the length of valve gate  200 , the extent between holes  256  and end face  254  of plug  256 , are predetermined to ensure that holes  256  and ports  154  will always be aligned and hence in communication with each other when spring  190  is fully compressed. An operator will then lock the sealant supply tubing in place against pull-back displacement in order to guarantee the established communication between holes  256  and ports  154 . The locking mechanism is not part of this invention, and is therefore not shown. 
     Once the sealant supply tubing is locked in place, the sealant material is pumped into the sealant tubing interior. This is done at the above-ground location where the new piping was fed into the old existing piping, which as mentioned, was at the gas meter. The sealant material flows internally through tubing  260 , and into central blind bore  255  in plug  250 , where it enters radially displaced holes  256 , exiting the removable assembly and into radial ports  154 , as indicated by the heavy dark arrow of FIG.  11 A. As sealant material exits radial ports  154 , the sealant is forced to change direction from that of its introduction direction and to follow a path of least restriction. As FIG. 2A illustrates, once the sealant enters annular space  17 , it has to change direction back towards the meter because the stopper assembly is sealing the annular space at points  86 A,  86 B,  96 A,  96 B, as previously described. As the sealant fills the air space volume, it simultaneously purges any entrapped air from annular space  17 , pushing it out from any leak locations  23 , until the sealant reaches and fills those locations. As the sealant moves further backwards, any remaining air will be purged at the meter, where the sealant is first introduced. After the sealant exudes from the exposed end of new piping  15 , the sealant pumping is terminated. The sealant tubing lock is then removed, and the sealant assembly is then removed from the interior of the new piping by pulling it backwards towards the meter, and completely out of the new pipeline. As the sealant assembly is removed, it should be understood that the sealant control valve also moves back to its resting and closed position as that shown and previously described with reference to FIG. 10, thereby preventing sealant from re-entering passageway  155  and the interior of pipeline  15 . 
     The sealant is of a material which begins to set almost immediately. Thus, it is possible to even pressure test the integrity of the sealant between the old and new piping shortly after its introduction. This particular sealant is unlike those previously used, where it was typical to have cure times of several hours before pressure testing of the sealant could be performed. 
     Pressure testing is now performed on the sealed annular space  17  by introducing a high pressure inert gas or air into the interior of new piping  15 . The pressure is held for at least 15 minutes while a pressure gauge (not shown) visually confirms that no leakdown is occurring. Once found satisfactory, the new piping  15  is again ready for receiving the high pressure gas that is on the high pressure (main) side of the seals  86 A,  86 B,  96 A,  96 B. 
     In order to reestablish service, a drilling tool is first inserted into the interior of new piping  15  and then through all of the assembled components comprising the apparatus of the invention, eventually reaching plastic pressure disk  68  received within end cap  62  of nosecone assembly  60 . The drill bit at the end of the drilling tool is of a diameter closely matched so as to slidingly fit within the hexagonal port  54 . It is also of a length where it does not have to be slid into the port  54 , but can operate upon disk  68  while being stationed within central passageway  55  of compression sleeve  50 . Those in the art are familiar with this type of drilling tool so no further explanation of it will be provided herein. Pressure disk  68  is then drilled-out to nearly the diameter of central passageway  65 , and once completed, high pressure gas will enter through the drilled-out pressure disk, into the hexagonal port  54 , and each of the respective central passageways of the sealing means, sealant introduction means, and retaining means, thereby filling new piping  15  with high pressure gas. Likewise with the alternate nosecone assembly of FIG. 8, once a drilling tool encounters and drills-out the plastic plug  233 , gas enters the central passageway of the apparatus of the invention and new pipe  15 . The gland assembly attached to the piping above the ground, at meter  27  is then removed, so that valve  26  can then be connected to new piping  15 , thereby re-establishing user service. 
     The foregoing description has been provided to clearly define and completely describe the present invention. Various modifications to the apparatus method of the invention may be made. However, those types of modifications do not depart from the scope and spirit of the invention, which is described in the following claims.