Abstract: An improved method and apparatus for trenchless placement of pipe or conduit that allows termination at a vault or manhole structure without destruction of the vault or manhole. The specific improvement is the means of making the bursting ram and all components used in the procedure (but for the replacement pipe) disassemblable in a small space, such as a vault or manhole. The disclosed improvement is a means to keep the bursting ram together during use but then to allow the bursting ram after it enters into the manhole or vault, to be disassembled with hand tools and removed in parts without destruction or damage to the vault structure. This makes the trenchless placement of conduit or piping non-destructive over the distance of the route as well as at the termination at a manhole.

Abstract: The present invention is directed toward a method for replacing or lining existing underground pipe. The present invention replaces the pipe between two manholes without the need to dig associated trenches. A diagonal pilot hole is formed by a piercing tool. A guide cable is passed through the existing pipe and pilot hole and attached to a ramming tool operative in bringing new pipe through the pilot hole, and into the existing pipe. The ramming tool bursts the existing pipe into the surrounding soil and replaces the existing pipe with the new pipe.

Abstract: Apparatus and method for the trenchless laying of pipework underground, having a tool and a gauge for the continuous widening of a probably wound preformed pipe on a linkage for use in pits of small dimensions, preferably inspection shafts of sewage systems.

Abstract: A horizontal well system, in accordance with the principles of the invention, includes a porous casing member having an interior space, a first end, and a second end, with at least a portion of the porous casing member being positioned substantially horizontally within an aquifer. This horizontal well system further includes a first casing member and a second casing member, with each of the first and second casing members having an interior space, an outer end, and an inner end. The inner end of the first casing member is connected to the first end of the porous casing member, with the first casing member extending toward the ground surface. The inner end of the second casing member is connected to the second end of the porous casing member, with the second casing member extending toward the ground surface.

Abstract: Several new bursting head designs and several hydraulic pulling arrangements for pulling such bursting heads through underground pipe for replacement of such pipes are disclosed. The new bursting head design utilizes a point of attachment inside the bursting head instead of at a clevis or pin on a bar extending out from the nose. The bursting head also uses a more shallow slope for the bursting head, and Chinese handcuff type cable and replacement pipe clamping mechanisms.

Abstract: A cable pulling apparatus for pulling a work load attached to a cable, including at least one cable-pulling device for engaging the cable. The cable-pulling device or devices each includes at least one cable-pulling member fitted with a cable-gripping element for pulling the cable and the workload.

Abstract: The basic features of the invention include a pipe parting mole, a length of cable that is engagable to the mole, a cable pulling device and a cable pulling device engagement means that provides a mounting structure for the cable pulling device. The cable pulling device engagement means generally includes a reaction plate and a structure for removably engaging the cable pulling device therewithin. A cable pulling frame may be advantageously used to facilitate the removal of the cable from a relatively small hole that is created at the pulling end of the pipe.

Abstract: An apparatus for inserting and removing a flexible first material into a second material (20) includes a moveable carriage (22). An adjustable clamp (24) is connected to the movable carriage (22), adjustable between an open position and a clamped position on the first flexible material. In a preferred embodiment, a receiver stiffener casing (26) is configured to receive and support the flexible first material as the flexible first material is inserted into and removed from the second material. In a preferred embodiment, in a slant drill rig (10) with a stationary track (14) and a movable drill (16) for drilling a borehole in ground (12), carriage (22) is connected to movable drill (16). An adjustable clamp (24) is connected to the carriage (22), adjustable between an open position and a clamped position. In a preferred embodiment, a receiver stiffener casing (26) is configured to receive and support cylindrical tubing as the cylindrical tubing is inserted into and removed from the borehole.

Abstract: An apparatus which guides a cable through a conduit. The apparatus includes a guide device for receiving the cable. Passage of the cable through the guide device is permitted. Further, the guide device is automatically moved from a first position to a second position during passage of the cable into the conduit to assist in the movement of the cable along the conduit.

Abstract: The invention relates to a process for introducing an optical cable, in the form of a microcable or minicable (1), in solid ground (17) with the aid of a laying unit (23). The microcable or minicable (1) used for this purpose comprises a homogeneous and pressurized-water-tight tube (8) which has an external diameter of from 2.0 to 10 mm and into which optical waveguides (3) are introduced.

Abstract: The invention concerns the replacement of underground pipes (52) wherein a former/cutting blade device (10) is pulled along the line of the existing pipe (52) by a cable fed (30) previously into the existing pipe (52). As the device (10) is so pulled it cuts and spreads the existing pipe (52). At the same time a new pipe (26) attached to the rear of the former (12) is pulled into place. The invention is of particular use in the replacement of small size lead water pipes which lead to consumer dwellings, and provides that the cable (30) which must be as large a diameter as possible to take the loads involved, is connected to the former (12) by having a ferrule (28) at one end which is located in a recess (27) in the former (12) so as not to interfere with the former profile. Also, the recess (27) is to the rear of the cutting blade (40) so that the ferrule (28) does not to cause an obstruction to the cutting operation.

Abstract: A drive mechanism for a subterranean boring machine includes a drive motor, primary and secondary drive wheels, a drive sprocket and an idler sprocket attached to the primary and secondary drive wheels, respectively, and a chain operatively extending between the drive sprocket and the idler sprocket. The drive mechanism is movably mounted on the sled of a subterranean boring machine that rolls along a track, the drive mechanism being biased against the track by a set of springs to cause the primary and secondary drive wheels to frictionally engage the track. The drive motor selectively and rotatably drives the primary drive wheel which, in turn, drives the secondary drive wheel. The drive mechanism translates the sled along the track under conditions when the sled is not driving a pipe into a subterranean location. The drive mechanism is configured to be largely self-contained to permit existing sleds to be retrofitted with the drive mechanism.

Abstract: Methods and apparatuses for rehabilitating and increasing the functionality of existing underground conduits wherein a plurality of conduits are simultaneously inserted into an existing conduit by bursting the existing conduit to create a tunnel and inserting a plurality of new conduits into the tunnel, such that at least one of the new conduits has a capacity equal to or greater than the capacity of the existing conduit, are provided. The new conduits are either separate from or removeably connected to one another, such that the new conduits are capable of being diverted from the tunnel at separate locations and the new conduit system can be used primarily for carrying media similar to that of the original conduit or additionally for completely different and unrelated media such as fiber optic cable, coaxial cable or electrical cable.

Abstract: An apparatus for bursting and replacing gas, water, sewer or other underground utility pipes. In a preferred embodiment the apparatus is characterized by a specially-designed rod-pulling device which is situated typically in a manhole or excavation, at one end of the pipe to be replaced. A rod is extended from the rod-pulling device through the pipe and is attached to a stored energy head disposed in a tapered bursting head which initially engages the opposite end of the pipe. A pneumatic hammer is typically seated in the stored energy head and a replacement pipe is removably attached to the bursting head. In typical operation, the rod-pulling device pus the stored energy head against the bursting head and thus, the bursting head against the pipe as the pneumatic hammer repeatedly strikes the stored energy head against the bursting head.

Abstract: A new method and apparatus have been developed which inserts and withdraws tubing from pipes without bending or kinking the tubing. Beneficially, the new method and apparatus may be employed to insert and withdraw tubing to depths greater than ever possible before. The method involves using a thruster pig to provide force to inject the tubing, and skate apparatuses to reduce coiling and friction of the tube. Advantageously, the apparatus is portable, easily handled, and adaptable to handle tubing of differing diameters.

Abstract: An apparatus for sealing a clearance between a host pipe and a liner pipe. The liner pipe is fed into the host pipe and includes a tubular element forming a leading end of the liner pipe. It also includes a compressible seal which is adapted when compressed longitudinally to expand radially and is mounted on the tubular element when in use. The seal moves freely with the element in the direction of feeding of the liner pipe. But when the liner pipe is retracted counter to the direction of feeding, the seal movement is arrested and the seal compressed longitudinally by the element so that the seal expands radially to engage the internal wall of the host pipe and seal the clearance.

Abstract: An apparatus for longitudinal splitting, in particular longitudinal slitting, of pipes laid underground and for the simultaneous trenchless pulling-in of a new pipeline comprises a carriage in the form of a frame, in which a cutting wheel for cutting open the pipe wall and a support roller, which serves as an abutment and is supported on the pipe wall, are arranged above one another. The carriage or frame has a base which engages in a form-fitting manner in a frame-like window of a pull and/or push linkage.

Abstract: In a process for laying a cable, or a protective sheathing for a cable core to be introduced into the protective sheathing at a later time, in a sewage pipe, the cable or the protective sheathing is fixed at particular spacings along the inside wall of the sewage pipe by means of clips. Here, the cable or the protective sheathing is diverted in the region of house lead-ins, so that the cable or the protective sheathing by-passes the house lead-in. The mutual spacing between the clips is substantially smaller in the region of the diversion than in the region of the straight path of the cable or the protective sheathing. The cable or the protective sheathing is anchored in the shafts and is pre-tensioned with a force of at least 250 N.

Abstract: A method and apparatus have been developed which inserts and withdraws tubing from pipes without bending or kinking the tubing. Beneficially, the method and apparatus may be employed to insert and withdraw tubing to depths greater than ever possible before. The method involves using a thruster pig to provide force to inject the tubing. The thruster pig uses a pressure differential to urge the tubing into and out of the pipe. Advantageously, check valves or relief valves allow fluid to be pumped down the tubing and out the front of the thruster pig, and then to flow back through the valves and up the annulus between the pipe and the tubing.

Abstract: A method is provided for removing an expander from a ground piercing tool of the type having an elongated tubular tool body with a front nose and a striker disposed for reciprocation within an internal chamber of the body to impart impacts to an impact surface for driving the tool forwardly through the ground. The expander is tightly fitted onto the nose of the tool body. The method of the invention uses a pulling device comprising a pair of arms ending in hooks and mounted at ends opposite the hooks to a yoke having a threaded hole therethrough, and a screw including a threaded stem inserted through and threadedly coupled with the hole. Suitable means are provided for engagement with a device for turning the screw.

Abstract: A device (6) for attachment to a pipe (7 to be installed in the ground has load cells (17) for detecting a pulling force applied to the pipe (7), as the latter is pulled through the ground, an inclinometer (18), for detecting the inclination of the device (6), and a pressure transducer (20) for detecting the pressure surrounding the device. Data representative of the pulling force, inclination and pressure is stored in the device (6) and protected against unauthorised access by a security code or procedure, so that a verifiable record of the pipe installation process is available.

Abstract: An impact boring tool according to the invention suitable for using with a directional boring machine has a tubular housing and a head mounted at a front end of the housing. The head preferably includes a chisel configured for breaking loose rocks and stones encountered in soil. A striker is disposed within the housing for delivering an impact force to the head, either directly or through one or more intervening parts. A trigger mechanism causes the striker to deliver an impact to the head and chisel only when an external force exerted on the impact tool in its lengthwise direction exceeds a predetermined level. This predetermined level generally coincides with a maximum effective amount of pushing or pulling force for moving the tool through the ground exerted by an external device such as a directional boring machine.

Abstract: The present invention provides a portable pulling apparatus suitable for mounting in an exit pit during installation of a pipeline. A portable pulling apparatus of the invention includes an elongated stake having a lower end portion configured for insertion into the ground and an upper end portion. A winch including a pulling cable is mounted on the upper end portion of the stake by a suitable fixture. The winch can then operate to exert a horizontal pulling force on a cable and is secured against movement when the lower end portion of the stake is inserted into the ground. Such a pulling apparatus can be used in a method of installing an underground pipe according to the invention.

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.

Abstract: A downhole tractor is provided that includes a housing and a first wheel assembly coupled to the housing that is operable to translate away from the housing in a first direction. The first wheel assembly has a first electric motor, a first wheel, and a first reduction gear assembly coupled between the first electric motor and the first wheel. A second wheel assembly is coupled to the housing and is operable to translate away from the housing in a second direction that is opposite to the first direction. The second wheel assembly has a second electric motor, a second wheel, and a second reduction gear assembly coupled between the second electric motor and the second wheel. A fluid ram is coupled to the first and second wheel assemblies for selectively translating the first and second wheel assemblies toward and away from the housing. A first controller is provided for controlling the flow of current to the first and second electric motors.

Abstract: The present invention provides a portable pulling apparatus suitable for mounting in an exit pit during installation of a pipeline. A portable pulling apparatus of the invention includes an elongated stake having a lower end portion configured for insertion into the ground and an upper end portion. A winch including a pulling cable is mounted on the upper end portion of the stake by a suitable fixture. The winch can then operate to exert a horizontal pulling force on a cable and is secured against movement when the lower end portion of the stake is inserted into the ground. Such a pulling apparatus can be used in a method of installing an underground pipe according to the invention.

Abstract: A device and method for enlarging a bore and installing a utility line. The device comprises an elongate shaft having a first and second end. The first end of the shaft is connectable to the drill string of a horizontal boring machine. The second end is connectable to a utility line or other device to be installed in the bore. The device is pulled through a pilot bore and enlarges the bore to a desired diameter while simultaneously pulling in a utility line. A set of cutting elements supported near the first end of the shaft, with 120 degree spacing therebetween, enlarges the bore to an intermediate diameter. A series of blades are supported on the shaft between the cutting elements and the second end. The first blade further enlarges the hole behind the cutting elements to the final desired diameter. Along its outer edge, the first blade comprises a plurality of teeth adapted to slice through the wall of the bore.

Abstract: An apparatus for widening microtunnels and/or for the destruction and replacement of ground-laid pipework and for the laying of new pipework possesses a tool which displaces the earth and/or destroys and/or displaces pipework laid in the earth, having a housing which is provided with an axial linkage seating, for example a housing passage for a linkage and with a linear drive which moves the tool, for example, on the linkage automatically from a launch pit to an arrival pit and simultaneously lays a follow-up pipe or a follow-up cable in the earth.

Abstract: In an apparatus for drilling in earth, a push-pull linkage, especially a ladder-type linkage consisting of individual sections connected together in each case by a plug-in coupling, is connected to a push-pull drive, and a stationary locking pawl and a thrust pawl which is moveable in the longitudinal direction of the linkage and is connected to the drive, with two mutually opposite directions of action, can each be brought into active connection with the linkage in order to move the linkage forward stepwise and lock it temporarily after each movement step.

Abstract: An apparatus adapted for movement through a passage formed in the ground includes an elongate element and means for positioning a shroud around at least part of the elongate element for engagement against the periphery of the passage to provide a space through which the elongate element can move. The shroud is of flexible construction and is arranged to be progressively installed in position as the elongate element moves along the passage. The apparatus is adapted for introducing an inflation fluid into the region between the shroud and the elongate element in order to inflate the shroud and maintain it in engagement against the periphery of the passage.

Abstract: A method and apparatus for laying a pipeline. Working and receiving pits are dug out. An active working member is dropped into the working pit at a preselected depth. The active working member is fixed to a vertical knife of a power mechanism. Polyethylene pipeline is secured to an end part of the active working member. Then the power mechanism is energized and simultaneously horizontal pulling forces of the power mechanism are applied to the vertical knife. The active working member may be a drill head with different nozzles (bits) connected with a mud supply unit by a hose passing through a hollow portion of the vertical knife. On a non-working end of the active member the pipeline is fixed by an adapter.

Abstract: An improved joint for a variable wall thickness conduit is disclosed. The joint includes a female joint section and a male joint section. The female joint section has a body portion which terminates in a first support surface and a sealing sleeve which extends beyond the first support surface. The sleeve has a first sealing surface and a thickness. The male joint section has a body portion that terminates in a wall and a sealing nose that extends beyond the wall. The wall has a width greater than the thickness of the sleeve. The nose includes a load bearing surface, a second sealing surface and a recess in the second sealing surface. The female joint section aligns and joins to the male joint section, the load bearing surface being in force transmittal relationship with the first support surface, whereby a gap is formed between the first sealing surface and the second sealing surface.

Abstract: A method and apparatus for replacement of an existing non-frangible pipeline includes creating open access to opposite ends of an pipeline and threading a cable having a wedge mounted thereon through the pipeline so that the wedge is positioned proximate one of the ends of the pipeline. The wedge is pulled through the pipeline from the other end of the pipeline so that the wedge slits the pipeline to form a slit pipe in a borehole. The slit pipe is removed from the borehole and a rear end portion of the slit pipe is attached to a front end portion of the replacement pipe . As the slit pipe is pulled out of the borehole, the replacement pipe is drawn into the borehole. The boring apparatus has a braided cable and a boring head having an expander sleeve and a lengthwise bore of sufficient diameter so that the cable can pass therethrough.

Abstract: A pipe/pulling frame is fitted to the tool end of a movable boom of an excavator, preferably via a quick-attach coupling. The boom first positions the frame in and out of the pit and then secondly holds the frame against twisting movement in the pipe-extraction pit during pulling, thereby obviating the need to provide shoring and other bracing. The frame comprises an actuator and a single reaction plate. The actuator pulls a segmented cable which extends through the pipe while the reaction plate structure bears against the pit wall. The actuator is further operable also to push a stuck pipe, for which the reaction structure is moved to the opposing end of the frame. A swivel is preferably fitted between the tool end and frame to allow the excavator to be positioned independent of the frame. An abutment member at the distal end of the old pipe is replaceable with a ground-reaming tubular pipe for pushing the trailing end of the old pipe and pulling the leading end of a new pipe.

Abstract: A drawing device 4 is mounted in a drawing shaft 3, and pipe replacement device A connected with new pipes is arranged on the side of starting shaft 2, wherein the drawing device 4 and the pipe replacement device A is connected through pull-rods 5 inserted into existing pipes with each other. The pipe replacement device A is comprised of a cutting part 11 including cutter bodies 14 (shanks 14a to 14i) arranged in the axial direction and at angular intervals in the circumferential direction, an expanding part 12 having expanding rollers 18a to 18f, and a connecting part 13. Each cutter body 14 has a plurality of cutting edges, wherein distances between the respective cutting edges and the center of the circle become larger in order from the forward side toward the backward side. While the pipe replacement device A is traveled in the inside of cast iron pipes, the inner wall of cast iron pipes is cut by the cutter bodies 14 to form grooves.

Abstract: A pipe pulling and pushing apparatus and method of operation, which apparatus includes a spring-loaded wedge device seated in a driving apparatus and fitted to a rod or pipe for forcing the rod or pipe beneath a road, pipeline or other barrier where trenching is not feasible. The spring-loaded wedge is characterized by a housing which receives a coil spring positioned to intermittently engage a wedge defined by wedge segments collectively having a rod bore and teeth for selectively gripping the rod or pipe when the spring is fully extended, and releasing the rod or pipe when the spring is compressed. Repetitive gripping and releasing of the rod or pipe by the wedge is effected responsive to operation of the driving apparatus to incrementally drive the rod or pipe through the terrain beneath the barrier. The spring-loaded wedge can also be positioned on the rod or pipe in the driving apparatus to pull the rod or pipe through the terrain beneath the barrier.

Abstract: A method and an apparatus for new installation or bursting and replacement of underground pipelines, without the necessity of trenches. This method and apparatus allows for the installation without the need for large excavations at the end point of the line and allows for nondestructive termination at an existing vault, structure or manhole without having to rebuild the structure, vault or manhole. The apparatus includes a head assembly that breaks apart fracturable pipe and expands the hole to accommodate the desired size of pipe. Because of the method of applying forces, the expansion of pipe diameter can be very substantial. Because of the head assembly, the head can be disassembled as the pipe and head enter a manhole, vault, structure or limited space and thus no need to excavate the vault or structure or create a large end excavation is necessary, thus saving time and money and avoiding disruption of traffic in street locations.

Abstract: There is provided a double walled pipe having an inner pipe and an outer pipe which is movable relative to the inner pipe in a longitudinal direction of the inner pipe. Acting on only the outer pipe with a pipe jacking power makes it possible to bury the double walled pipe, without damaging the rear end of the inner pipe and also generating an internal stress on the inner pipe. Consequently, it is avoided such a situation that even in use pinholes, cracks, etc. occur on the inner pipe, and thus it is possible to expect an execution with higher reliability.

Abstract: A utility power unit (10) for underground drilling and pipe laying operations comprises a stationary frame portion (12), a movable frame portion (14) capable of performing sliding movement relative to the stationary frame portion (12) and hydraulic cylinders (44) between the stationary and the movable frame portions (12, 14) for effecting the relative movement. The movable frame portion (14) includes an attachment (36) for removably attaching a tool connecting member (38) thereto and a further attachment (40) for removably attaching a rotary drive unit (52) thereto. The invention also provides a method of directional boring along an intended underground path (62) comprising the steps of providing a machine pit (60) at a location along the intended path (62) and drilling a bore along the intended path (62) by means of directional drilling apparatus (10) which includes a stem (30) provided with a drill (68) at a forward end thereof.

Abstract: A bore hole support system is formed from a flexible liner that is readily everted within a bore hole and forms a bore hole support system to install a casing in the bore hole while supporting the bore hole walls. After a pilot hole is drilled, the pilot hole is traversed with a reamer to form the pilot hole diameter to a larger diameter for the final bore hole. The flexible liner with the attached casing is everted and pressurized behind the reamer as the reamer traverses the pilot hole to support walls defining the bore hole while pulling the casing into the bore hole. The liner is simply removed from a storage and everting canister and remains with the casing in the bore hole. In certain circumstances, the liner may be coated with a water soluble material so that the casing may be in fluid communication with the bore hole walls when the coating has dissolved.

Abstract: A replacement pipe is installed within an existing service pipe (1) by first advancing a sealing means (6,8) along the existing pipe to a position adjacent its junction with a main pipe (2), then deploying the sealing means to seal against the inner surface of the existing pipe) in the example shown, by pumping sealant (10) into the space between the seal body (6) and the pipe (1), and subsequently advancing the replacement pipe along the existing pipe. The space between the two pipes is then filled with sealant and finally the sealing means is opened, in the example shown by withdrawing a guide rod (5) and its collar (7) on which the sealing means was advanced into position.

Abstract: A method for lining a conduit with a deformable plastics liner pipe, the claimed method including deforming the liner along its length to a cross-section with reduced external dimensions relative To the dimensions of the undeformed liner and binding the liner by helically winding an elongate flexible element around the liner along its length to maintain it in the deformed cross-section. The method further includes drawing the bound liner into the conduit to be lined and releasing the binding to allow the liner to assume a cross-section substantially corresponding with the internal cross-section of the conduit. The elongate flexible element is supplied to the liner from a bobbin or the like through which the liner is passed in the deformed cross-section, the bobbin or the like being mounted for rotation around the liner as it passes therethrough to wind the elongate flexible element around the liner.

Abstract: A boring head is provided for use in mounting to a drill pipe of a drilling rig for enlarging a pilot bore in horizontal boring operations. The boring head has an axial member positioned along a central axis of the boring head for connecting the boring head to the drill pipe of the drilling rig. A plurality of flanges extend radially from the axial member, and a flange support frame is provided for structurally interconnecting and supporting the flanges on the axial member. A plurality of cutting cones are mounted to the boring head. In particular, each of the cutting cones has a cone axis, each of the cutting cones is mounted to one of the flanges such that its cone axis extends at an acute angle ranging from zero degrees up to about 45 degrees relative to the central axis; each of the cutting cones is mounted for independent rotation about its cone axis; and each of the cutting cones has a plurality of independently rotatable cutting bits mounted thereto.

Abstract: The method concerned is for connecting a section of buried main conduit (120) to a secondary conduit. For this purpose, a starting pit (200) and a finishing pit (204) are dug, a drilling device comprising a series of rods to be placed end to end is lowered into one pit in a manner such as to drill along a horizontal axis at the level of or at a height close to that of the main conduit. Upon completion of the drilling, the secondary conduit is passed through the bore-hole (202) in a manner such that an end portion is situated above the pit, this portion is fixed to a first region of a branch connector for connecting the two conduits and this end portion, equipped with its connecter, is lowered into the pit and the connector is fixed to the main conduit.

Abstract: A method for underpinning a building comprises arranging at least one elongated supporting element below and substantially parallel to the foundation of the building. A whole side wall of the building may thus be underpinned in a single operation without unnecessarily weakening the existing underground. By coupling a plurality of elongated supporting elements, a kind of large-surface foundation that securely supports the building can be created. The architectonic substance of very old buildings may thus be preserved in a non-aggressive manner. In addition, the underpinning method can be carried out very quickly and at a relatively low cost.

Abstract: The apparatus and technique of the invention constitutes a hydraulic jack system for pushing sections of new pipe which, in turn, pushes a sleeve-cone expander arrangement to break up the old pipe and define a straight path for the new pipe. Apparatus is employed to determine the skin friction and the penetration friction, and to dispense a lubricant to reduce such frictional forces.

Abstract: A method is provided for supporting and sealing structure defining a generally cylindrical hole while introducing and removing devices from the hole. A first flexible liner is installed in the hole and pressurized to a pressure effective to support and seal the structure. A second flexible liner is everted between the first flexible liner and the structure, where the second flexible liner carries the devices to introduce and remove the devices from the hole while the first liner remain pressurized to continuously support and seal the structure.

Abstract: An apparatus and method for inserting a new service pipe into an existing service pipe without the necessity of excavation or separately shutting off the supply of gas upstream of the effected pipe section comprises of a nosecone allowing a flow of sealer to travel back through an annular space between the new pipe and the old pipe, providing a gas tight permanent seal.

Abstract: There is provided a double walled pipe having an inner pipe and an outer pipe which is movable relative to the inner pipe in a longitudinal direction of the inner pipe. Acting on only the outer pipe with a pipe jacking power makes it possible to bury the double walled pipe, without damaging the rear end of the inner pipe and also generating an internal stress on the inner pipe. Consequently, it is avoided such a situation that even in use pinholes, cracks, etc. occur on the inner pipe, and thus it is possible to expect an execution with higher reliability.

Abstract: The invention relates to a process for pulling a pipe (2) laid and/or to be laid in the ground to a trench below and accessible from ground level, in which there is a traction system in engagement with a traction component (3). The traction component is taken through the pipe and engaged with its rear end, viewed in the pulling direction. The traction component with the pipe is then drawn to the trench in steps by the traction system, with the traction device making a forward and a backward stroke at each step. During the backward stroke the traction component is kept under a tension corresponding to its elastic expansion during the forward stroke. In this way the traction component is kept permanently under tension throughout the pulling process, thus preventing the traction component from alternately expanding and contracting at each step.