FR2630185A1 - METHOD AND APPARATUS FOR INSTALLATION AND EXTRACTION OF PIPELINES IN EXISTING PIPING NETWORKS - Google Patents

Abstract

The invention relates to the repair of deteriorated pipes. It relates to a method of repairing pipes in which a new pipe is placed in an old deteriorated pipe. According to the invention, the replacement line is a rigid line 10 capable of withstanding hydraulic and other pressures. It is heated so that it is folded back on itself and then wound up, the manufacture being such that the piping preferably retains a shape memory property in this folded state. When it is to be placed in a pipe, it is heated enough to be flexible. After placement, it is heated and expanded so that it takes on a circular configuration. Application to the repair of secondary sewers.

Description

The present invention relates to process improvements and

  installation apparatus for a stretch of

  replacement pipeline in an existing underground conduit

  for example, a section of pipe that needs to be repaired or replaced. In particular, the invention relates to the installation of a spare pipe section in the sewers of buildings that intersect the networks.

  sewers, in other secondary sewers,

  ducts, in sections of pipe that may have tight curves and elbows, and in other sections of pipe

  which are intersected by sewers of buildings and in-

  which the connections of the secondary pipes would be difficult to locate after the installation of a new

  section of pipeline in the existing section.

  Various methods and apparatus for the repair of underground pipelines have already been suggested, for example - sewer pipes and the like, the existing pipeline remaining in place in the ground, by installing a flexible membrane in the existing pipeline, or a plastic coating, or by introducing a new plastic pipe into the

existing pipeline.

  In a known method, pipes are coated

  of a flexible plastic material such as polyethylene

  lene. In this process, the coating is introduced by

  through introduction pits carried out at certain

  intervals along the pipe, so that

the process is expensive.

  In another method illustrated for example in US Patent Nos. 3,927,164 and US Pat.

  4,064,211, a flexible tube is returned to itself when

  inflated and hunted in a section of canalisa-

  from a first end of the section. This

  This method is expensive because it requires special equipment.

  cial, a large heating and expensive materials.

  The aforementioned methods and most other

263O18S

  yielded a flexible or semi-flexible coating

  who can not withstand external pressures

  reliable, hydrostatic or applied by the soil. Thus, the existing pipes can not be repaired properly because, if any part breaks, the coating may eventually sag under the action of external pressure of sufficient amplitude, for example

  pressures that exceed about 0.3 bar.

  U.S. Patent Nos. 4,394,202 and 2,794,758 also disclose methods of introducing a flexible tube into an existing pipe under

  form of a coating membrane of this pipe.

  The first of these patents discloses a method of attaching the flexible tube to the existing conduit using a short expandable portion of a rigid plastic material coated with an adhesive. The processes of the two patents show the

  disadvantages already described with reference to prior methods

  using a material in the form of a mem-

  soft brane, because it does not present the resistance

  tangential mechanics necessary to support the pressures

  hydraulic or ground-based external sions.

  It has also been suggested that a rigid pipe be introduced into an existing pipe to be repaired. For example, in the published British patent application

  No. 2,084,686, a rigid plastic tube of

  circular and oversized design is flattened or its dimensions

  are reduced in another way to the work site, and is then introduced cold and rigidly into the existing

  important formed at the level of a manhole. After introduction

  duction, the plastic tube is expanded by heating

  fage and under the action of internal pressure. The tube of

  plastic material is expanded against the existing piping

aunt.

  According to British Patent No. 1,580,438, a hose

  existing subterranean soil is coated with a plastic coating tube made of a plastic material such as polyethylene or polypropylene,

  having a shape memory property. The coating tube

  It is manufactured with a non-circular U-shaped configuration so that it fits into the existing piping, it is then introduced, with its non-circular shape, into the existing piping and it is then expanded against the existing piping under the action of heat and a

  pressure so that it takes its circular form.

  European Patent Application Publication No. 0 000 576 suggests the introduction of an insert formed of a semi-rigid plastic tube into existing piping. The semi-rigid plastic tube has sufficient tangential mechanical strength to support all or some of the pressures

  externalities that can be applied to it.

  at. Repairing Curved Pipes and Pipes with Single-End Access Most of the aforementioned known methods and others

  processes employing rigid or semi-rigid

  Rigid for introduction into existing underground piping have a common drawback: because of their substantial or partial rigidity, they must be introduced into existing pipes that are straight or almost straight. It means by

  example, in the case of underground sewers, that these procedures

  Known dice are limited to main sewers because they usually have straight sections of pipe between the manholes. Most, if not all, of these known methods can not be used for

  repair of the numerous sewers of buildings that are

  between the sewer system and the buildings. Frequently, such secondary lines have curves or elbows that can not be followed by rigid piping or

  semi-rigid plastic material. In addition, such

  secondary applications can not be normalized

  Also, the known methods of coating or installing replacement pipes requiring a manhole or other access at both ends are excessively expensive. . In most known methods of installing underground underground piping, significant excavations must be made.

  at one end of the secondary pipe

  which must be lined or repaired so that a space

  delimited for the introduction of

  replacement line formed of rigid plastic material. A

  such an important excavation near a building des-

  served by the secondary pipe or at the other end o the secondary pipe intersects the network is often

  impossible in practice and is usually expensive.

  In addition, most of the known methods of repairing

  or coating of existing underground pipes

  aunts require access to the section to be repaired at both ends of the section. This is not possible in the case of a secondary pipe which, by definition, intersects a main pipe at a location that is not

  usually reached by a manhole.

  For the above reasons, known methods for coating and repairing underground pipes

  do not apply to sewers in buildings.

  b. Major Sewer Repair Another disadvantage of the use of known methods of repairing and coating sections of existing pipelines intersected by sewer pipes of buildings by use of rigid or semi-rigid straight pipes is that when the pipe is in the existing pipeline section, it is very difficult to locate the exact positions to which

  secondary pipelines served cut across the canal

  main opening so that access openings must be cut from the replacement tube to provide access to the service secondary lines. This applies in particular when the spare tube has a sufficient thickness and consequently a tangential mechanical resistance sufficient to withstand itself the hydraulic and soil pressures which can

to be applied.

  For the foregoing reasons, methods,

  Advanced tools and equipment for the repair of existing sections of underground pipes, including building sewers and other pipe sections with elbows and curves, and sections of pipe that can not be easily reached at both ends of the pipe to repair, are necessary.

  Consequently, the invention relates essentially to

  1. A new and improved product in the form of a replacement line to be installed in an existing subsurface duct and particularly suitable for the repair and replacement of pipelines.

  existing sewers of buildings that are not

  lines and main lines intersected by the sewers of the buildings, 2. a new and improved process for the manufacture of a product constituting a repair and replacement pipe particularly suitable for assembly in

  existing underground conduits that are not

  lines or which are intersected by secondary pipes

  3. a method of installing a new or replacement section of pipe in an existing underground conduit, and in particular a conduit that

  is not rectilinear or is cut through

  building sewers, 4. an appliance and tool for the manufacture of a product in the form of a replacement pipe as

  5. apparatus and tools for the

  of a product in the form of a pipe as indicated, in an existing underground pipe, and in particular in such a pipe which is not rectilinear or

  which is intersected by secondary service lines

  and 6. an appliance and tool intended for the reshaping of a new or replacement section of thermoplastic piping installed in an existing subsurface duct, and in particular a building sewer, after new or replacement has been introduced in folded form, by handing to a circular configuration

stable in the existing duct.

  More specifically, the invention relates to an improved pipeline repair and replacement product which is particularly suitable for installation in an existing underground conduit, such as a building sewer having bends and curves, and a series of methods,

  equipment and tools used for the

  the product, for the installation of the product in an existing duct, whether straight or curved, and

  for the delivery of the product in a form of circular section

  after it has been introduced into the existing duct in folded and crushed form. The product, processes, apparatus and tools of the invention are intended to be used for the installation of the product in building sewers and other existing underground conduits having access only at one end of the driven and having curves and elbows or that are intersected by

secondary pipes.

  In a first aspect, the invention relates to a product in the form of a replacement pipe formed of a thermoplastic material, for example polyvinyl chloride, extruded and shaped initially with an original configuration flattened and folded so that he

  keep a shape memory property when warming up

  fage, and that it can be easily rolled up to be stored and used, so that it has a reduced section

  allowing its easy introduction into an underground conduit.

  existing rain, and that it can be introduced without excavation

  or deterioration of the plastic material in canalisa-

  deep holes, through manholes, cleaning holes or other small vertical apertures, and in tight elbows, and so that, despite its flattened folded shape, a hot fluid can

  circulate so that it warms it along its entire length.

  In another aspect, the invention relates to the

  the aforementioned product in the form of a plastic pipe, in an existing curved secondary pipe, for example, by reheating the plastic pipe so that it is flexible, then by pulling the flexible pipe, folded and hot in the existing secondary line with a traction cable and either with a pulley assembly temporarily attached to

  the intersection of the secondary pipe and the canal

  main use, either with a winch from the manhole closest to the mainline. The folded and installed pipe is then heated on

  its entire length by circulation of a hot fluid,

  hiding or reducing its anterior extremity, and injecting

  a fluid, such as air-pressure, at the other end so that the pipe changes shape and

  dilate taking its rounded configuration. Then,

  days by applying internal pressure to the channeling

  circular fitness, this one can get cooler

  and so it stabilizes to its circular configuration.

  In another aspect of the invention, various devices

  They are used for blocking or reducing the dimensions of the anterior end of the plastic piping so that a hot fluid can circulate when it is bent, and yet allows the expansion and reforming of the pipe. folded so that it takes a circular configuration, by application of a

  fluid exerting an internal pressure.

  The invention also relates to a device for sealing or sealing an inlet end of the folded pipe so that it can be pressurized by an internal fluid when it has been introduced.

  in an existing underground pipeline.

  The invention also relates to an original apparatus for

  pulley and cable that can be pushed into a channel

  secondary service to its intersection with a mainline and which can be used

  temporarily by maintaining a tension at both ends.

  the cable. A first end of the cable is attached to the front end of the folded pipe which is to be mounted; the opposite end of the cable and then pulled so that the bent pipe of plastic material is pulled into the existing secondary pipe then

  that she is in a hot and supple state.

  In another aspect, the invention relates to various devices for heating opposite ends and

  various other parts of the product in the form of a channel

  sation of plastic material so that the selected parts of the pipeline can undergo operations allowing clamping, the introduction of plugs or the setting of the entire length of the pipe to a sufficiently flexible state

  for it to be introduced into an existing conduit

so much that is not rectilinear.

  Other features and advantages of the invention

  will be better understood by reading the description

  which will follow examples of embodiment, with reference to the accompanying drawings in which;

  FIG. 1 is a sectional view of a thermally

  conventional plastic, for example chloride piping

  of polyvinyl used according to the invention, in the

  dilated area; Fig. 2 is a perspective view of the thermoplastic piping of Fig. 1 and apparatus for passing the tubing from its circular configuration to a folded and crushed state for storage on a spool;

  FIG. 3 is a sectional view of the heat pipe

  plastic of Figure 2, after its folding, along the line 3-3 of Figure 2; FIG. 4 is a schematic view illustrating a method of setting up the thermoplastic piping

  folded and wound in FIGS. 2 and 3, in a main sewer

  pal, from a manhole, the thermoplastic piping

  folded tick being stored on a roll and being warmed

  to be installed in the underground piping

which must be rebuilt;

  Figure 5 is a schematic section of a detail of.

  the apparatus for expanding the thermoplastic piping

  folded in FIGS. 2 and 3 and put it in circular form.

  after its introduction into the main pipe.

  existing blade as shown in Figure 4; Figure 6 is a schematic sectional view of an alternative structure of expansion and placing the thermoplastic piping folded in rounded form after its introduction into an existing conduit; Figure 7 is a schematic sectional view of a building sewer example disposed between a building served by a main sewer, this figure illustrating a method of installing the thermoplastic piping in an existing building sewer, by implementing invention; FIG. 8 is a cross-section of a preferred example of thermoplastic piping of FIG. 1, after folding

  allowing installation in an existing underground duct

so much;

  FIG. 9 is a diagrammatic elevation of an apparatus

  thermoplastic piping manufacturing line of Figure 1, in folded form as shown in Figure 8; FIG. 10 is an elevation of the device for calibrating the apparatus of FIG. 9, to a larger extent

  scale, used for the manufacture of thermal piping

  moplastic as shown in Figure 8; Fig. 11 is an elevation of a single calibration plate of the device of Fig. 10, along the arrows 11 of Fig. 10; FIG. 12 is a plan view of a folded end portion of the thermoplastic piping of FIG. 8, having an end clamp formed therein so that the piping can be drawn into an existing conduit and thereby that the end of the conduit is closed in a manner that allows the piping to be

  an internal pressure allowing its expansion;

  Figure 13 is a section along the line 13-13 of Figure 12;

  Figure 14 is a relatively schematic plan view.

  of a pulley and cable apparatus according to the invention.

  tion, which is also shown in Figure 7, for pulling the folded thermoplastic tubing of Figure 8 into a secondary service line, the apparatus being shown in the working position; Figure 15 is similar to Figure 14, but

  represents the device in the folded state so that it is

  duit in a secondary pipe; Fig. 16 is a schematic side elevation of the apparatus of Figs. 14 and 15; FIG. 17 is a side elevation of a plugging tool used for plugging an end of a thermoplastic pipe section shown in FIG. 8, after the end has been rounded, the tool being used for transmission of a fluid, heat

  and pressure inside the thermo piping

plastic;

  FIG. 18 is a front end elevation

the tool of Figure 17;

  FIG. 19 represents one end of the pipe

  thermoplastic material, the plugging tool of Figures 17 and 18 being introduced into the pipe and clamped in place by a chain clamping device; Fig. 20 is an elevation of the chain clamp of Fig. 19 prior to application to the tubing and plug of Fig. 19; 21 is a section along the line 21-21 of FIG. 19, showing the chain tightening tool of FIGS.

  Figures 19 and 20 tightening the end of the heat pipe

  moplastic on the capping tool of Figures 17 to 19; FIG. 22 is a diagrammatic longitudinal front end section of the thermoplastic tubing of FIG. 8, the end clamp of FIGS. 12 and 13 being applied to the end of the tubing and the remainder of the tubing being expanded in the form of circular, a

  cutting tool according to the invention being introduced at the end.

  the piping so that it cuts the tight end of the rest of the piping; Fig. 23 is a section of the tubing and cutting tool of Fig. 22 taken along line 23-23 of Fig. 22; Fig. 24 is a schematic side elevation of an end heater used for the

  heating of an end portion of the thermo piping

  plastic when the end portion is to be shaped, the heating tool being shown mounted on a bent end portion of the thermoplastic tubing of Figure 8;

  FIG. 25 is a perspective of an inflating tool

  end capping flanging used for blocking or reducing the size of the end of the piping

  thermoplastic instead of the clamping device of ex-

  tremity of Figures 12 and 13 so that the

  folded plastic can be expanded and placed in a circular form; Figure 26 is a shortened elevation, in partial section, of the inflatable tubing of Figure 25; Fig. 27 is a schematic view illustrating the installation of the inflatable plugging tool of Figures and 26 in the thermoplastic piping when in the expanded state and of circular section; Fig. 28 is a schematic view similar to Fig. 27 but showing the tubing of Fig. 27 after it has been folded over, the inflatable cap being in the deflated state therein;

  Fig. 29 is an illustrative diagrammatic elevation

  utilizing the inflatable plugging tool of Figs. 25 and 26 when installing thermoplastic piping in a secondary service line; Fig. 30 is a schematic side elevation illustrating another application of the inflatable capping tool of Figs. 25 and 26;

  FIG. 31 is an illustrative diagrammatic elevation

  the use of the inflatable capping tool

  FIGS. 25 and 26 during the implementation of the method

glossy in Figure 30;

  FIG. 32 is an illustrative diagrammatic elevation

  Another application of the inflatable

  FIGS. 25 and 26 during the expansion and the circular forming of the thermoplastic piping

  folded after it has been inserted into a

  existing land; Figure 33 is a schematic side elevation

  a section of mainline and a pipeline

  which crosses it, illustrating another process

  of thermoplastic piping as represented

  shown in Figure 8 in a secondary pipe to be repaired; Fig. 34 is a schematic side elevation of an end portion of the folded thermoplastic piping of Fig. 8, illustrating a separation process.

  cable pulling the anterior end of the pipe-

  after it has been introduced into a

  ground; FIG. 35 is a schematic side elevation similar to FIG. 34, illustrating another method of

  separation of the pulling cable from the heat pipe

  plastic when it has been introduced into an existing underground conduit; FIG. 36 is a sectional view of the intersection of a main line and a secondary service line after the thermoplastic piping of FIG. 8 has been installed and dilated in the main line to be repaired, this figure illustrating a method of

  locating and cutting an opening in the pipe-

  thermoplastic terrier that has just been installed so that

  communication is reopened between the secondary line

  and the mainline; Figure 37 is a schematic side elevation

  illustrating a method and apparatus for folding a pipe

  thermoplastic material which has been manufactured in

  to be inserted into an underground conduit.

  existing rain; Figs. 38A to 38E are schematic sections along the lines A-A through E-E of Fig. 37; Fig. 39 is a diagrammatic side elevation of a removable end clamp and a pull cable and a release line attached thereto and which is used for clamping the anterior end of the bent tubing. of Figure 8 during installation;

  FIG. 40 is a plan view of the forceps of

  tremité of Figure 39; and Fig. 41 is a plan view of the portion of the

  release corner of the clamp of FIG. 39.

  Repair of Main and Similar Sewers Referring first to Figure 1; 10 denotes a type of piping that is used for the

  reconstruction, repair or replacement of

  underground pipelines such as sewers and the like according to the invention. A characteristic of the

  piping is that it is formed of a thermoplastic material

  such as polyvinyl chloride and more precisely

  of a material which is normally rigid and which has

  thick walls so that it has a mechanical resistance

  Tangential flow sufficient to accommodate the hydraulic external pressures and applied by the soil to which it can be exposed when it is in the ground. However, such thermoplastic piping can be made in a flexible form when heated to temperatures of, for example, 93 C or higher in the case of PVC piping. A feature of the pipe 10 is that it is rigid at temperatures

  ambient conditions prevailing above the ground and

  below the ground, but becomes flexible and deformable so that it takes various configurations when heated or reheated. Another characteristic of a

  such a thermoplastic material is that it has a

  priety of form memory; thus, when it is

  with a particular configuration, for example a tubular shape of circular section, then it is heated and flattened or folded and then cooled so that it

  stabilizes to its folded configuration, then warmed up free-

  it tends to return to its tubular configuration

  original circle of circular section. Conversely, when the pipework is initially manufactured for example in folded or crushed form as shown for example in Figures 3 and 8, then when it is heated and subsequently expanded under the action of an internal pressure so that it takes a circular shape and then when it is

  cooled and stabilized to its circular shape, it tends to

  dance to its original folded form when it is reheated later by being free. This aspect of

  shape memory of thermoplastic piping is

  advantageously according to certain aspects of the pre-

this invention.

  A conventional and readily available piping of the type useful for the practice of the present invention is a polyvinyl chloride (PVC) piping having standardized aspect ratios of dimensions (diameter

  wall thickness) between 13 and 65, currently

  available for underground pipelines,

  such as evacuation lines, canalisa-

water, etc.

  Although, in one embodiment of the invention,

  The thermoplastic piping is manufactured in folded form as shown in FIG.

  described with reference to the apparatus of FIGS. 9 to 11,

At least some aspects of the present invention may

  also be implemented by means of a thermo-

  plastic manufactured in tubular or circular section. FIG. 2 shows a device 11 intended to modify the configuration of the conventional piping 10 of FIG.

  polyvinyl chloride which has been manufactured with a

  Circular guration. Figure 3 shows the section of

  the piping after it has been shaped by apla-

  bending and folding with the apparatus of Figure 2. Specifically, the PVC pipe is heated from any

  conventional way, for example by a heating device

  lla, which can be a thermostatically controlled steam box

  or a box containing heating elements.

  electrostatically controlled electric fog. When passing the original circular pipe 10 in the heating box Ila, the pipework is brought to a temperature

  sufficient for it to take a plastic or supple state.

  It is then flattened or preferably folded, in a folding apparatus 11 intended to reduce the total dimension

  of its section so that it can be pulled easily

  in an underground duct having an internal diameter equal to or only slightly greater than the original outer diameter of the thermoplastic piping. Thermoplastic piping in folded form of reduced size is

  designated by the reference 10a in FIG.

  Although the assembly 11 of Figure 2 schematically shows a pipe bending device, a method and method of bending pipework that is practical in use are shown in greater detail with reference to the apparatus of Figures 37 and 38A-38E. Note that the pipe 10 of circular section, - after passing through the heating device 11a, is first flattened by two opposite rollers 60 and 61 and passes under a wheel 62 of folding being supported progressively by three sets

  different types of folding rollers 63, 64, 65. The two rollers

  Folding beams 63 cooperate with the wheel 62 to begin to give the pipe 10 a U shape. The three folding rollers 64 continue the folding operation as they are placed with a wide enoU shape in cooperation with the machine. folding wheel 62. Finally, the game of

  four rollers 65 of folding has a U-shaped configuration

  putting the cooperation with the wheel 62 so that the folding of the U-shaped pipe 10 is finished. Then, the bent pipe passes into a retaining mold 66 during its cooling so that the pipework is stabilized

  to the U configuration so that it has a

  After the mold 66, the bent tubing can be stored in predetermined lengths of length or transmitted to a tube of water vapor so that it is heated and made flexible to be

  introduced directly into an existing conduit.

  In a variant, after the flattening operation and before folding, the pipe may be rolled up flat

  in the heating chamber 18 shown in FIG.

  The flat and rolled piping can then be reheated in the box at the work site, then pulled out of the heating box and folded as previously described.

  just before introduction into the pipework to rebuild.

  In some applications, it is also possible

  to install the thermoplastic piping in a pipe-

  existing land in a flattened form, especially when the

  thermoplastic piping, with its circular configuration

  has an external diameter much smaller than the diameter

  internal meter of the pipe to be repaired. However, in

  most conditions, it is preferable that the pipe-

  Thermoplastic material is installed in a pipe

  existing, in folded form longitudinally as

  shown in Figure 3, 8 or 38E. However, among all the folded shapes, the shape of Figure 8 is preferable

  for the reasons given below.

263018 S

  As mentioned earlier, thermoplastic piping

  tick, when manufactured with a circular section

  1, has a shape memory property tending to return it to its circular configuration when it is reheated after folding. Thus, if it is necessary to warm the bent pipe so that it is flexible to fit into an existing pipe, it tends to return to its circular configuration, perhaps

  prematurely, if it is not retained. It's main-

  For this reason, it is preferable

  Thermoplastic material is initially manufactured in the desired folded form. Then, when the bent piping is reheated to be flexible to enter an existing pipe, it keeps its folded configuration until it is fully introduced into the existing pipe and ready to be returned in circular form.

  Regardless of the fact that thermoplastic piping

  The tick is manufactured in a circular or folded form, the piping must be in folded form when ready to be introduced into the existing duct. It is also preferable for the thermoplastic piping to be wound by being heated and thus made flexible on a storage spool such as the spool 12 shown in FIG. 4. The spool 12 of the folded thermoplastic piping is kept in a box or "hot box". 18 having a thermostatically controlled heating device 24 for heating the inside of the heating chamber and thus the coil 12 so that the material of the bent pipe 10a is flexible at the desired time. Preferably, the heating chamber 18 also has a water circulation circuit 19 for preventing stratification of the heat in the heating box and thus for uniform heating of the coil of the folded pipe. The heating casing 18 is preferably mounted so that it can be transported and is shown mounted on the platform of a transport truck to the work site. A smaller sized hot box can be mounted on wheels and moved manually when it is to be used for the treatment of inaccessible small pipelines such as sewer-buildings. In any case, a motor or manual device is for rotating the spool 12 so that the material is wound on the spool and unwound therefrom. The heating box 18 has an access door 21 and may also include

  a spout 22 and a roller 23 facilitating the introduc-

  folded thermoplastic piping in a cannula

  A method of repairing a main sewer In one aspect of the invention, the heating box 18 is transported to an underground access port through a vertical access opening such as a manhole 16 of the existing main sewer. opening formed at the work site, for example the manhole, at a section of underground piping such as the main sewer 14 to be repaired. The end of the pipe 10a in folded form is connected to a pulling line 26 introduced by an adjacent opening of the pipe

  existing, for example another manhole (not shown

  tee), and is connected by a clamping device 28 or -

  clamp at the free or anterior end of the new piping. This is made flexible by heating the

  coil 12 in the heating chamber 18, using the arrangement

  heating system 24. The traction line 26 is then controlled for example by means of a winch placed at the next manhole, in front of the manhole 16, so that the folded and flexible pipe 10a is unwound from the reel. 12 through the spout 22 and passes around a roller 23 carried by the spout before entering the

  existing pipework 14, to the next manhole.

  After introduction of the new folded pipe, this

  It is heated and expanded to a circular or substantially circular shape and forms a thick-walled rigid-wall pipe having a tangential mechanical strength sufficient to withstand hydraulic and soil external pressures. Figure 5 illustrates a method of expanding the reduced-size piping after it has been drawn into the original piping to be rebuilt or replaced. In this process, two plugs 30 and 32 are introduced at opposite ends of the bent tubing

  when the extremities at least are in the flexible state

  fe. The plug 30 is placed at a rear end of the new pipe section which is placed at the insertion end of the existing pipe. The plug 32 is placed at the front end or contact with the

  traction line of the new piping, after decon-

  connection of the traction line. Each of the plugs 30 and

  32 has a peripheral lining 34 which can be expanded

  ter and which is intended to temporarily cooperate sealingly with the original piping 14 and the new

  piping 10a. The pads 34 are inflated by the

  intermediate of pipes 36 of air transmission com-

  awarded, joining the control device (not repre-

  felt) placed above the ground. The plug 30 has an inlet duct 38 which passes therethrough and which allows the introduction, in the new pipework, of an expansion fluid, by

  example of live steam or hot water. Such a con-

  to a suitable control valve 40 and a pressure gauge 42 and a relief valve 44. The plug 32 has

  an evacuation conduit 46 communicating with the

  between the two plugs and having a suitable tap

nable 48.

  The bent pipe that has just been installed,

  when the corks are introduced at its opposite ends

  It is then heated internally by the circulation of live steam in small passages formed at the level of the folds of the new piping and appearing clearly in FIG. 8. The valve 48 placed at the downstream end is open so that the entire length of new piping is heated. The valve 48 is then closed while the

  steam under pressure continues to penetrate through

  30 and put the bent piping under pressure so that it changes shape and expands

  taking a circular configuration. If the new pipe-

  terie is manufactured in the folded state, it must be cooled or must be able to cool after having taken its circular form, with preservation of the internal pressure, by

  example applied by cold air so that the pipe

  terie hardens with its circular configuration. This last step is not necessary if the piping is manufactured in a circular configuration, unless it is dilated or stretched beyond its diameter

  origin during the shape change operation.

  If no internal passage is present in the new

  bent tubing folded, for example in the case where the new piping is bent perfectly flat as shown in Figure 3, the new piping must be heated from the outside, for example by live steam circulation in the existing piping, before plugs 30 and 32 are introduced at the ends of the

  new piping. Then, when the new pipe-

  the plugs 30 and 32 can be easily introduced at the opposite ends, the valve 48 is closed and live steam or

  hot water is introduced through the

  chon 30 so that the bent piping is expanded and replaced

to a circular configuration.

  Figure 6 represents another type of apparatus of

  expansion of the reduced size piping. This appa-

  It comprises a mandrel 50 provided with a heating device

  fage 52 placed inside and able to heat the new pipe to the flexible state. The mandrel 52 is connected to a towing cable 54 or other device for pulling it into the original piping. After proper heating of the mandrel and applying a tensile force to the cable, the mandrel is drawn into the original piping and expands the new piping so

  let it take the desired diameter. Obviously, in this

  given, the cable 54 traction is introduced into the new pipe before it is bent to

  to be introduced into the existing pipeline.

  - A third method of heating, circulating and expanding the new piping includes filling the existing piping to be repaired with hot water or steam, along the new piping installed but still folded , until

  the desired temperature is reached at the downstream end.

  The new piping is then pressurized with hot water or steam and is expanded under pressure to a circular configuration,

having the desired diameter.

Example

  In a particular pipeline reconstruction process, conventional PVC piping is used, its outer diameter being about 13 mm less than

  internal diameter of the pipework that has to be rebuilt

  trout. The piping has the normalized ratios between the wall thickness and the outer diameter, as previously indicated. The PVC tube is heated to a temperature

  at least 93 to 100 C, and is folded to the

  shown in Figure 3, 8 or 38E. The bent piping is then stored on large coils so that it can be towed to the job site. During the installation in an underground duct or existing piping, the new piping is heated again, preferably in a heating box 18, so that it is flexible and can be easily pulled in the vertical downward direction in a hole deep man then in horizontal general direction in the existing conduit. After installation in the existing duct section, the bent pipe is plugged, heated and placed in a circular state. If necessary, it can also be expanded beyond its original or nominal diameter so that it fits snugly against the existing section.

of pipeline.

  Method of locating sewer connections of buildings

  An advantage of the expansion of the thermal piping

  The moplastic that has just been installed, beyond its original nominal diameter, is illustrated in FIG. 36 on which the existing section of pipe to be repaired is intersected by at least one building sewer or another secondary service line. In Figure 36, the

  main line 70 is intersected at 72 by a canal

  secondary installation 74 such as a sewer of a building.

  When the new thermoplastic piping is installed

  in mainline 70 and is placed under

  circular shape and dilated or stretched beyond its di-

  original nominal meter to cooperate intimately with the internal wall of the existing pipe 70, a protrusion or swelling 76 is formed at the opening or intersection 72 of the secondary pipe and the main pipe. This bulge 76 in fact indicates the precise location of the opening of the secondary pipe in the main pipe. The location

  of the bulge and thus the opening of the

  secondary education can be determined by the circulation of a

  television camera in the main pipeline.

  Then, a remotely controlled cutting tool 78 can be introduced into the main pipeline to the exact location of the bulge and can be used to cut the bulge 76 into the new pipeline.

  , so that it ensures again access between

  Secondary 74 and major.

  The operations of placing in a circular form is

  dilatation or elongation of the thermoplastic piping

  which has just been installed are provided by the methods described above or described hereafter.

  reference to other embodiments.

  Preferred form of folded tubing Although the folded and flattened thermoplastic pipings of FIGS. 3 and 38E may be used in the previously described installation methods, FIG. 8 shows the preferred form of such bent tubing 10. Thermoplastic tubing 10 of Figure 8 is

  practically manufactured with the folded form shown.

  It generally constitutes a flattened tube folded with a generally curved longitudinal fold 82 formed in

  protruding between two overlapping and

  a relatively long branch 83 and a relatively short branch 84. The long branch 83 leads to a

  curved or projecting free end 85 intended to delimit

  miter a small longitudinal passage 86 in the piping

  folded. Curved branch 84 also ends with one end

  curved or projecting free spring 87 which also delimits a longitudinal passage 88 in the pipework. In addition, the gradually curved portion 82 defines a passage 89 on

  along the inside of the fold, from one end of the hose

to another.

  The ends of the branches and the curved folds

  described its importance to avoid the tearing of

  folded folds of the piping when folded, as could be the case if the piping was folded flat as shown in Figure 3, especially when it has thick walls. The passages 86, 88 and 89 are also important to allow water vapor or other hot fluid to flow over the entire length of the bent pipe to be reheated and modified after installation. piping bent in a conduit

  existing underground. In the absence of such access to the

  folds, reheating would be a long process

and slow and very difficult.

  The folded shape of the pipework of FIG.

  is particularly suitable as replacement piping for the repair of sewers of buildings, such as sewer line 90 shown in Figure 7, from an intersection 92 with a main line 94 to a building 96 to be served. First, such secondary canals pose difficult access problems because they are often formed under lawns, trees and bushes and are not reached by

  through manholes. The extraction of a boat

  existing secondary

  must be repaired is so very expensive. During the introduction

  In the case of a new secondary pipe in an existing underground secondary pipe, in general, access is practically usable only from a single small vertical excavation adjacent to the building as indicated by reference 98 in Figure 7. Such an excavation leaves little room for maneuvers or

for a voluminous apparatus.

  Building sewers are usually much smaller in diameter than the main sewer and often have sharp curves and elbows,

  to the main pipelines which are generally

  lines from one manhole to the next. For example, the sewer

  the building has a bend 100 making it impossible to introduce

  duction of straight rigid piping in the canal

  existing secondary education. In Figure 7, the sewer 90, reached by the vertical excavation 98 adjacent to the building 96, is disposed below a lawn 102 and joins the main sewer 94 at a substantial depth below a street 104. The methods and apparatus described herein are particularly suitable for solving the original problems of installing replacement piping in an underground secondary pipe from a single small access opening.

  which is vertical in a general way. These processes and

  they use the thermoplastic piping folded under the

  shape shown in Figure 8.

  Method and apparatus for manufacturing a thermo-plumbing

  plastic in folded form Referring to FIGS. 9, 10 and 11; the bent thermoplastic tubing of FIG. 8 is made using a conventional extruder 106 of plastic tubing which extrudes into a vacuum box 108. Traction devices comprising a series of opposing pinch rolls 111 , 112, placed downstream of the vacuum chamber, pull the extruded material and shaped from the vacuum chamber, under tension, and the

  transmit to a tube 114 of steam intended for warming

  iron in a flexible form so that the resulting folded pipe can be wound into folded form into a roll 116 which is for example placed in the box

heater 18 of FIG.

  A die 118 and a punch 120 are placed at the exit of the extruder. There is a space between about 30 and 60 cm between the downstream end of the die

  118 and the inlet of the vacuum chamber 108.

  The vacuum chamber is divided internally by

  partitions 122, 123, in three sections. The three sections

  We are filled with water to a level 124 inside the box. The first section or upstream section of the box is connected to a source 125 of vacuum. Although the whole

  vacuum chamber is depressed because of this

  the maximum depression prevails in the upstream section of the caisson. A calibration device 126 is placed in the first section of the vacuum box. These measures

  calibration is used to put the extruded plastic

  to the desired folded configuration and its maintenance to this configuration when the material cools and hardens

  so. The water present in the vacuum chamber has a function

  cooling, and the depression transmitted to the

  caisson ensures, in cooperation with the

  brage, holding the plastic material in the desired folded form until it can keep its shape without

retained, thanks to the cooling.

  Referring now more specifically to Figures and 11; the calibration device comprises a series of

  plates 128 placed at a distance from one another and

26301 85

  provided by mounting rods 130, the plates being

  held at a distance by spacers 132 placed between

  they on the stems. The rods are threaded at their ends.

  The calibration plates 128 closest to the inlet end are closer together than those further downstream, given the greater plasticity and fluidity of the inlet. plastic material in the inlet portion and accordingly the greatest need for the retention of the extruded material to the desired shape in this part of the sizing device. The latter may also possibly comprise a central tube 136 having

  orifices 137 for transmitting cooling water

  the plates and between them so that the material

  plastic cools quickly.

  Referring now to FIG. 11, each calibration plate 128 has an aperture 138 precisely cut with exactly the configuration and outer dimension of the contour of the bent tubing formed and retained in the plates. All plates 128 have

  exactly the same size and configuration of

  Verture. The comparison of FIGS. 8 and 11 indicates that the opening 138 of the plate comprises a short branch 138a corresponding to the short branch 84 of the folded piping and a long branch 138b corresponding to the branch

  length of the piping and a bent part

  die 138c corresponding to the rounded longitudinal fold 82 of the pipe. In the manufacture of the piping of FIG. 8, an initial mixture containing the plastic material, by

  example of polyvinyl chloride, is introduced into the

  the extruder 106 by a feed funnel 107 in which the material is heated to an elevated temperature for example of about 130 C, before extrusion by the die 118, where the very hot plastic material meets the punch 120. die and the punch have such dimensions that they give the plastic the

  dimension and the desired final configuration for the tube.

  The plastic is transmitted in the space 121 and then in the first section of the vacuum chamber 108 and in the calibration plates. The plates ensure the setting of the plastic material to the configuration and dimension

  determined by the openings 138 of the plates and its

  to this configuration and these dimensio When the plastic material first enters the

  calibration device, it is very hot and relatively

  fluid, so that the plates 128 are very close to each other so that they maintain the desired configuration. The depression in the box

  ensures the maintenance of the plastic material against the

  outside of the opening 138 when cooling water

  says the plastic material. If necessary, compressed air injected from a source 140 into the punch 120 can flow in the internal passages 86, 88, 89 of the folded plastic element so that the plastic material does not collapse. totally and that the bent piping retains a tubular shape. At the moment when the plastic material reaches the downstream end of the calibrating apparatus 126, it is substantially cooled and can retain its force under the action of the tension applied by the traction rollers 110. These rollers pull the folded plastic

  out of the vacuum chamber in the form of a continuous strip.

  After the calibration plates, the band passes into the second and third chambers of the vacuum chamber in which they gradually harden. At the moment when the strip 10 leaves the box under vacuum, it is cold, rigid and practically in the form shown in FIG. 8. The pulling member 110, when pulling the strip or the stream of material coming from the extruder under tension, ensures adjustment of the thickness of the wall and

  other dimensional parameters of the folded piping.

  After the traction member 110, the folded strip passes into a tube 114 for receiving water vapor circulation.

  water vapor from a source 115 through an opening.

  117 so that the band is warmed up and softened

  and can be wound on a storage reel 116.

  The number and spacing of the calibration plates

  used in the device depend on the speed of

  trusion determined by the traction device and

  the desired wall thickness of the finished pipework.

  As indicated previously, the coil 116 of the

  bent pipe 10 can be placed in the heating box

  shown in FIG. 4 so that it is trans-

  worn and used at the work site.

  Method, apparatus and apparatus for installing a pipe

  Thermoplastic surface in a secondary pipe

  Figure 7 not only represents a secondary sewer

  as described above, but also illustrates a

  process, equipment and tools necessary for the in-

  troduction of this folded piping of Figure 8 in this secondary sewer. First, a vertical excavation 98 must be dug, preferably as close as possible to the building 96 served by the secondary pipe 90, so that the existing pipe can be broken and

  that access to it is obtained.

  The section to be repaired or replaced in the canal

  secondary education can then be determined by introducing

  flexible fiberglass rod in the canalisation.

  at the level of the excavation and in advance of the rod in the secondary pipe until it intersects the main sewer 94. At this time, the length of the rod in the secondary pipe may be marked

  at the access opening and the rod can be removed

  measured and measured so that the length of piping 10

  plastic material necessary for the work is

  born. When the lengths of a series of secondary pipes to be repaired are known, the bent pipework 10

  can be precut so that it corresponds to these lon-

  either at the manufacturing plant or at another location distant from the work site. Then the pre-cut sections can be transported to

  work locations to be installed.

  Alternatively, the necessary sections can be cut at the working location from the coil 116 or 12 (Figure 4), in the heating chamber 18 transported to the workplace. If the excavations intended for the secondary pipes to be repaired are not

  accessible for the truck 20 on which the heating box

  When the stage 18 is mounted, the required length of plastic tubing 10 can be stored on other smaller coils placed in heating chambers. smaller wheels mounted (not shown), rolled to the respective excavations. A small heating box 140 is shown in FIG. 7 around a coil 142 of

folded piping 10.

  In a variant, in place of the prior measurement and the prior cutting of the folded pipe sections 10 to the lengths of the pipes to be repaired, the bent pipe 10 can be simply heated in the heating box 140 and introduced into the existing secondary pipe until the new piping reaches the intersection with the main line 94,

* and it is then cut at the level of the coil.

  In addition, when the folded pipe 10 of plastic is pre-cut lengthwise at the factory, it can be transported in pre-cut sections to the various work locations, then heated to be introduced into the existing pipe, in a steam tube such as the tube 114 shown in Figure 9. The steam tube may be formed of a fabric or metal or equivalent materials, with flexible ends

  of fabric or equivalent material that can be used

  around the bent tubing of plastic so that the steam remains in the tube. Such tubes are light so that they are easily transported to the place

  use and may have a length of 6 m or more.

  A tube of cloth is preferable to the metal tube for a

  use on site, for reasons of weight.

  When the secondary sewer is straight and when

  its access opening at the level of the excavation is sufficient

  close to the surface or where the excavation is

  sufficiently large, it is possible to introduce the

  piping of plastic material in the existing sewer by simply pushing the new piping into

  existing piping until the anterior end

  reaches the main sewer. However, this is not

  not possible in many cases because the new pipe-

  must follow an elbow at the level of the excavation and / or

  along the secondary sewer. In this case, it is necessary

  to heat the normally rigid folded tubing so that it is longitudinally flexible and follows the elbows, and to pull the new tubing folded into the secondary sewer instead of pushing it. The application of a pulling force to the flexible folded pipe in the existing sewer, without access opening at the main sewer, poses particular problems solved

according to the invention.

  Draw a new secondary line in an existing secondary line from the access opening

  A process of introducing a new channel

  in an existing secondary sewer by application of tensile forces uses a traction cable attached to the front end of the new pipe. The cable passes over a pulley at the secondary sewer and main sewer connection and returns to the secondary sewer entrance. When a pulling force is applied to the cable from the access port formed at the level of the excavation 98, the new piping may be

  pulled along the entire length of the existing secondary sewer.

  This process requires special tools.

  First, the anterior end of the new

  it shall be clamped in closed form so that the dimensions of passages 86, 88, 89 of Figure 8 are reduced as much as possible and that the bent piping can be pressurized internally when it has been introduced into the existing secondary line, with

  possibility of circulation of hot fluid in the pipe

  bent so that it can be heated along its entire length and made flexible so that it can expand and become circular. An end clamping device shown in Figures 12 and 13 is used for this narrowing and clamping of the end. Fig. 22 also shows a secondary elevation of the end clamp. In these figures, the end clamping device 144 comprises two rigid metal plates. The plates include an upper plate 145 and a lower plate 146. Both plates have nose portions 147 protruding forwardly and having aligned holes 148 for connecting a cable therethrough. Two other aligned holes 149 are formed in the lower and upper plates behind the

  hole 148 for the passage of a bolt 150 clamping. Celui-

  it also happens in aligned holes 151 drilled in the

bent piping.

  When the end clamp 144 is mounted on

  the anterior end of the folded tubing 10, the end

  A prior art tubing is heated to be flexible, for example in an end heater 152 shown in FIG. FIG. 24. This apparatus 152 - comprises a rigid thin-walled pipe 154 closed to

  a first end by a plate 156 having an opening

  the central inlet 157 provided with a connection 158 of a flexible pipe of water vapor. The other end of the heater comprises a flexible envelope 160 of fabric or other suitable fabric, fixed by a band 162 connecting to the pipe 154. The free end of the envelope 160 can be fixed or held by a band around the plastic tubing 10 so that water vapor can escape to the casing and pipe fitting 164 so that the entire end of the tubing is heated to a temperature desired temperature after injection of water vapor into the pipework through the connector 158. The length of the pipe 152 may be about 0.6 m, in most applications, although it may be larger or smaller following the application. After the anterior end of the tubing 10 has been put into the flexible state, the plates of the pliers 144 are applied to the end of the tubing, and a bolt 150 is placed in the holes 151 and is tightened so that the plates 145, 146 clamp an intermediate portion of the folded pipe in flattened form and reduce the size of the passages 86, 87, 89 at the end of the folded pipe. It should be noted that the widths of the plates 145, 146 are substantially smaller than the total width of the pipe 10 so that the passages 89 at the fold 86 at the end of the long branch are not completely closed when the application of the clamping force to the folded pipe. Thus, when the clamp is applied, fluid can still pass through the end

  tightness of the piping, but the passages are sufficiently

  low for the pressure to rise to the

  folded piping and allows the expansion of

  piping and placing it in a circular form.

  The aforementioned end heater apparatus is also useful in other applications as described in

following the description.

  Removable end pliers Another type of end pliers that can be used in place of pliers 144, is a removable pliers

  250 shown in FIGS. 39 to 41. The forceps 144

  has the disadvantage that it can not be removed from the anterior end of the pipe 10 when it has been inserted into a blind duct, without cutting the tight end of the duct with a special cutting tool controlled remotely as shown in Figures 22 and 23 and described hereinafter. However, the removable clip 250 can be separated

2-630185

  remote from the tight end of new piping where applicable and can be pulled out of the existing duct

by the cable.

  The removable gripper 250 has a superior jaw

  256 on a lower jaw 256. The lower jaw 256 has a projection 258 at its front end, having a hole 260 through which a traction cable passes through and allows the attachment of a cable 262. jaws 252, 256 have ends

  263, 264 for clamping and compressing an earlier part

  end piece 266 of the bent tubing 10 of material

  plastic, when it is warm and supple.

  A bolt 268 passes through a larger aperture 270, larger than that of the bolt head 269, and into a smaller aligned hole 272 of bolt passage formed in the lower jaw 256. The hole 272 is smaller than the bolt hole 269. nut 273 and the head 269 of the bolt 268. A forked member 276 constituting a release wedge has parallel arms 277, 278 which define a slot 280 and which are connected to a vertically disposed corner body 282. A flexible release cable or rope 280 is attached to the body 282 by passage through the hole 286. The wedge 276 is intended to be wedged between the head 269 of the

  bolt 268 and the upper surface of the upper jaw

  252, the arms 277, 278 being placed under the head and the slot 280 housing the bolt rod. Thus, the head 269 of the bolt is pulled against the arms 277, 278 and not in

  the large aperture 270 of the upper jaw

  when the bolt is tightened so that the ends 263, 264 of the jaws are held against the piping 10. When the clamp is to be separated from the new piping after it has been drawn into the existing secondary sewer. using cable 262 and after the new piping has been put into circular form, except

  at the tight end, the release cable 284 is pulled.

  It then pulls the corner 250 from under the head 269 of the bolt (or the nut 273 when the end of the bolt carrying the nut is above the upper jaw), so that the bolt head can pass in the opening 270 of large size of the upper head 256 and allows the opening of the jaws and the release of the end of the pipe. The wedge and clamp can be removed from the secondary or main line using

respective traction cables.

"Frog" with pulley and cable

  Another tool used to pull the new pipe

  Secondary soil folded into the existing piping at

  Access opening 98 is a pulley and cable device called a "frog" as shown in FIGS. 14 to 16. This frog 152 has a cable passage pulley 157 mounted in a housing 156 so that it

  can rotate around an axis 157. Two articulated branches

  158 are placed on either side of the open rear end of the pulley housing. Each branch has an anterior section 158a and a rear or rear section 158b which is integral therewith. Two flexible guide strips 160 formed of steel and bent inwards at their rear ends 161 are placed behind the rear sections 158b. The pivot pins 162

  branches 158 on the housing 156 are recalled elastically

  so that the branches are pushed back to the ex-

  as shown in Figure 14. However, the

  branches can pivot inwards towards the posi-

  shown in Figure 15 so that the branches and the entire assembly can move in the

secondary piping.

  Two branches 164 of triangular general shape are articulated to the connections of the front and rear sections

  158a, 158b at the pivots 166 recalled by

  spells. These pivots 166 push the arms 164 towards their

  advanced position shown in Figure 14, perpendicular

  the rear sections 158b, when in the forward positions of FIG. 14. However, the arms 164 can be folded despite the force of the springs to the positions shown in FIG. 15, so that the frog can move in a secondary conduit to its destination. A traction cable 168, whose two ends return to the access opening 98, passes

on the wheel 154 of the pulley.

  When the traction cable 168 is attached, but

  when both ends of the cable return to the

  98, the frog is introduced into the existing secondary sewer and is pushed using a flexible fiberglass rod (not shown). When the frog reaches the intersection of the secondary duct and the main duct and when the casing 156 and the associated pulley are pushed into the main duct, the

  previous branches 158a entering the main duct

  pal, the arms 164 spring elastically outwards from the positions shown in Figure 15 to the open positions shown in Figure 14. In the open position of the branches, the rear sections 158b and the connected strips 160 are applied against the inner wall of the existing duct. At this moment, the two ends of the cable 168 are pulled so that the frog

  firmly attached to the secondary pipe connection

daire and main.

  When a voltage continues to be exerted in the pulling cable so that the frog remains fixed in place, one end of the cable is attached to the end clamp 174 (FIGS. 12-13) or to the removable clamp 250

  (Figures 39-41). The other end of the cable, which is

  days placed in the access aperture 98, is pulled and it pulls the folded and heated flexible pipe 10 of plastic material into the secondary pipe and at the elbow 100 until the front end of the

  folded pipe 10 reaches the intersection of the canalisa-

  The tractive force can be applied to the cable 168 for this purpose either by hand or by means of a manually controlled winch 170 (FIG. 7) placed at the opening 98. access. Given the triangular shape of the arms 164, the

  cable tension 168 prevents the switching of the

  noodle up and down.

  After the new tubing folded of material

  plastic reached the frog placed in the canalisa-

  In this case, the cable connection at the end clamp is removed and one end of the cable is pulled into the pulley so that the frog falls into the main line. The cable is then removed from the secondary pipe, from the inlet opening, and the frog can be recovered later in the main pipe by carrying out processes.

  classic recovery. The folded pipe 10 of

  plastic material is then fully introduced into the secondary pipe to be repaired, its anterior end

  tight located at the mainline.

  The folded pipe of plastic material can then be heated and expanded to a circular configuration, in

  the existing secondary pipeline.

  Before the description of the dilation operation and

  of a circular shape used for channeling

  secondary conditions, the process and the

  separating the cable 168 of the clip 144 from

  so that the cable can be removed from the frog. This can be done in many ways

  as shown for example in Figures 34 and 35.

  Figure 34 shows a release of the cable by a breakable link. In this method, a "relaxed" end 168a of the cable 168 is attached to a breakable cable or link.

  of relatively low mechanical strength which is itself

  even fastened at 173 by a ribbon to an anterior portion of the folded tubing 10 which must enter the existing secondary line. From the relaxed end, the pull cable 168 forms a loop with play passing through the hole 148 formed in the end clamp, as indicated by the loosened loops 168b, 168c, and pass

  then on the pulley of the frog. The end of trac-

  The cable remains at the level of the access opening to the secondary pipe. If an end clip is not

  used, the hole 148 can be pierced directly to the ex-

  folded anterior end of the plastic piping. When the winch located at the access opening pulls the cable through the frog so that the new bent pipe is drawn into the existing secondary pipe, the link 172 maintains a

  moderate tension at the relaxed end 168a of the cable.

  When the anterior end of the new folded tubing reaches the frog, the pulling end of the cable is shaken sharply, with breakage of the link 172 and release of the end 168a of the cable through the hole 148 if

  although the cable can be recovered.

  Figure 35 illustrates a similar method of liberation

  cable, considered as a method of liberation

  a hand-held cable. In this process, the part

  Stretch of cable 168 again forms two loops arranged

  with play in the hole 148 of the cable at the anterior end

  the new folded tubing 10 so that the double loops 168b, 168c are formed. The cable 168 is then disposed in the existing secondary pipe 90

  to the frog and back to the entrance opening.

  The relaxed portion 168a of the cable must have a length greater than that of the new pipework 10 which must

  to be introduced. When the winch pulls the new pipe-

  in the existing secondary pipe, a moderate tension force exists in the end 168a of the cable and

  allows the new piping to be pulled into the cana-

  secondary education. When new piping is properly introduced into the existing pipeline,

  the end 168a of the cable is released at the opening of

  so that the cable can be separated from the anterior end of the pipe which has just been introduced,

by passing through the opening 148.

  Method and Apparatus for Expanding and Circulating Folded Piping in a Secondary Pipeline When the new, folded piping is in place in the existing secondary piping, it is ready to be expanded and circulated to

  replace the existing secondary line as

  in operation. At this moment, the front end

  the new bent pipe 10 is already tight

  by the end clamp 144 or 250 so that the pipe

  bent clay can be put to an internal pressure by a fluid, steam or other hot fluid can however pass inside. This allows the heating of the folded pipe over its entire internal length.

  so that it is flexible and can be expanded. obviously

  at this time, the rear end of the bent pipe that has just been introduced is also closed so that the introduction of steam or other hot fluid into the piping is possible and allows the heating and dilation. Such a closure device or stopper

  is shown in Figures 17 to 21.

  A cap of conical general shape, called "bou-

  chon torpille "176 has an anterior portion 178 of generally conical shape having an orifice 180 at its end

  earlier. The conical portion 178 is directed to the

  in a short cylindrical portion 82 which is closed by a rear end plate 184. The plate 184 has an inlet port 186 and a flexible pipe fitting 188

  intended for the connection of flexible

  in steam or hot water so that pressurized hot fluids can be introduced into the folded tubing. Other flexible pipe fittings may also be formed in the

  end plate 184, for example a hose connector

  air space, allowing the expansion of the piping with the aid of compressed air or the maintenance of an air pressure in the dilated piping during hardening in the state

dilated and circular.

  When the rear end of the bent pipe 10 is heated, for example by the heater apparatus 152 described above, so that it is flexible, the conical portion of the torpedo plug 176 is introduced to

  the rear end of the pipe 10 as shown

  shown in Figure 19, until the cap 184 is

  abutting against the end edge of the new pipe

  teria and causes dilation of the end of the

  new piping to a circular configuration corresponding to

  laying at the outer diameter of the portion 182 forming a cylindrical plug. An adjustable chain clamp 190 is used to clamp the expanded end portion of the new tubing to the cylindrical portion 182 of the torpedo plug so that the tubing co-operates

waterproof with the cap.

  Details of the chain clamp 190 are shown in FIG.

  Figures 20 and 21. The chain clamp has a clamping plate 192 having a curved surface 193 of

  cooperation with piping. The external surface of

  convex bure of the plate carries a stirrup 194 inside which a nut 195 can rotate. The nut 195 houses a threaded rod 196 having a clamping end 197. A clamping chain 198 is connected to the other end of the

  rod. The chain is preferably a chain of

  or bicycle or the like. The chain can be adjustably connected to an anchor post 199

  placed on the outer surface of the clamping plate 192.

  When the end of the pipe 10 has been heated

  and when the torpedo plug 176 has been inserted into this end, the clamping plate 192 is placed on the end of the circular piping and

  the chain 198 is wrapped around the cylindrical end

  The tightening pressure is then applied by rotation of the threaded die 186 in the direction that shortens the effective length of the chain 198, using the same amount of force. a clamping tool cooperating with the end 197 of the rod. It is important that the pliers be tight because the plastic piping tends to deform when heated, and the pliers must be clamped in place during heating and placing the new pliers.

  velle piping to a circular shape.

  When the torpedo plug is tightened in position at the rear end of the piping that has just been

  introduced, a flexible pipe of water vapor is connected

  corded to a connector 188 of the cap. Hot steam is driven along the length of the bent piping and more precisely in the small passages formed therein so that the entire length of the piping can be heated. Simultaneously, the shrinkage formed by

  the end clamp at the anterior end of the hose

  terie allows it to be put under an internal pressure of up to about 1.75 bar. When the piping heats up and is under pressure, it expands and begins to form a cylindrical shape throughout its length,

  except at the narrow end portion.

  When new piping is expanded and placed in a circular shape to the desired size, usually

  against the internal wall of the existing secondary

  the plastic piping can cool while internal pressure is maintained for example by

  introduction of compressed air, so that the new pipe

  terie can stabilize at its new rounded shape.

  When the new piping is stabilized, the

  chain is separated from its posterior end and the

chon torpedo is removed.

  Removal of the tight end of the new piping The next step involves the extraction of the end clamp and the still-bent and tight front part of the new piping, from the remaining circular part of this piping. The operation is performed by cutting the tight and folded anterior end of the new expanded and circular pipe as

  shown in Figures 22 and 23.

  In Figures 22 and 23, a cutting device

  which is shown is intended to separate the anterior end

  folded and tightened pipe of the expanded and

  10 in existing piping. The cutting device comprises a motor cutting tool 200. This tool has a small electric or pneumatic motor 202

  operating at high speed, housed in a cylindrical casing

  motor drique 204 whose diameter is clearly less than

  the internal diameter of the pipe 10 of material

  plastic of circular shape. Flexible plumbing of food

  compressed air supply or an elec-

  The tag 206 transmits power to the motor 202 from a remote source, placed at the inlet opening of the existing secondary line. A drive shaft 208 carries a rotor 201 to which are fixed hingeably two cutting blades or flails 212, 213, at pivots

  214 adjacent to the outer ends of the rotor.

  The motor housing 204 is housed in an inflatable rubber sleeve 216 which, when expanded, centers the cutting assembly in the circular shaped plastic tubing and secures it therein. A flexible air supply pipe 218 transmits

  the compressed air for inflating the sleeve 216.

  Although the blades 212, 213 shown are formed of steel, they may also consist of a cable or a chain. They are intended to deviate under the action of the centrifugal force when the rotor 210 rotates, striking and cutting the pipe 10 of material

plastic.

  In use, the cutting assembly 200 is pushed along the new pipe 10 after it has been installed and put into circular form. The thrust can be achieved by a flexible rod of

  glass, the rubber sleeve 216 being deflated. The apparent

  - Cutting wire is pushed into the existing secondary pipe until it reaches the folded and tight front end. At this time, the sleeve 216 is inflated so that the cutting assembly is fixed and centered in the circular section piping. When the sleeve is

  inflated, the motor 202 is powered by power transmission.

  The motor drives the rotor 210 which controls the blades 212, 213 until the blades 210 have been driven.

  cut the folded and tight end of the piping. The ex-

  cut end falls into the main pipe and can be retrieved later by

classical processes.

  After separation from the anterior end of the pipework, the sleeve 216 is deflated and the cutting assembly is withdrawn from the pipe of circular section by a simple pull on the pipe 218 or the pipe.

  cable 206 from the inlet end of the new pipe

  crocheted. A new secondary pipeline is then installed.

  installed in the existing pipeline and, after connection

  the part of the secondary line leading to the

  Building 96 (Figure 7), it is ready for use.

  Other methods and apparatus for installing and dilating

  the new piping in a secondary pipeline.

  Fig. 33 illustrates another method of pulling a bent pipe 10 of plastic material

  access opening 98a of an existing secondary line

  aunt 90a intersecting a main line 94a at an intersection 92a. At a certain distance from the intersection 92a, the main pipe 94a has a manhole 216 intended to provide access to the main pipe. A

  winch 218 is placed at the manhole 216. The ex-

  anterior tremity of a cable 220 is introduced into the

  existing secondary channel 90a at the opening level.

  98a and is pushed towards the intersection 92a by a flexible fiberglass rod whose front end carries a clamping member of the front end of the

traction cable.

  The anterior end of the push rod is

  curved so that when it reaches the

  section, it can be directed around-the net formed corner

  in the main pipeline. At this moment, the stem

  continue to push the cable 220 into the main pipe as indicated by 220a, until the forward end of the pull cable reaches a manhole 216. The anterior end of the cable is attached to the cable winch in 219. The rear end of the cable

  220, always placed at the opening 98a of access to the channel

  90a, is connected to the front end of the bent pipe 10, using one of the cable release methods described above. The new pipe, after it has been heated for example in the heating box 18 so that it is flexible, is pulled into the existing pipe 90a by winding the cable 220 with the winch 218 placed at the hole man

  216. The draw continues until the front end

  the new piping 10 reaches the intersection

  92a. The cable 220 is then separated from the anterior end

  of the new piping using one of the techniques previously described. The new piping can then

  dilated and placed in a circular form in the canali-

  existing secondary school 90a, by the above method or

  another method described in the following.

  Method of Placing Circular Piping Using an Inflatable Cap Another method and apparatus for expanding plastic piping that has just been installed in an existing secondary line is illustrated in FIGS. at 29. This process is considered

  as an "inflatable cap" method. The gon cap

  222 used in this method is shown in FIGS. 25 and 26. It is used in place of the end clamp 144 (FIGS. 12 and 13) or the clamp 250 (FIGS.

  39 to 41) for the total or partial closure of the

  anterior inaccessible of the new piping so that it can be put under pressure, placed in circular and dilated form. The cap can support a

  pneumatic pressure of at least 1.75 bar, it can expand

* ter to an outer diameter corresponding to the internal diameter of the new piping in circular form, but it does not burst when it is not retained by the new piping. The cap must also be made so that it

  can withstand a temperature above 93 C.

  The inflatable cap can be constructed with a single layer of a flexible material, if a flexible material

  having the above properties can be found. How-

  However, such a suitable material has not yet been found

  Vee. As a result, a new construction is being

  two-layer stopper. The plug is composed of an outer tube of fabric or other fabric 224 which is folded, closed and sewn at the anterior end 225. The outer tube 224 has an expanded diameter which corresponds to the

  desired internal diameter of the new piping when

  it has a circular shape. The posterior end 226 of the fabric tube remains open. An expandable inner tube of rubber or bladder 228 is placed in the fabric tube. The total length of the plug can vary between about 0.3 and 6 m, depending on the application. The posterior ends of the outer tube of fabric and of the inner rubber tube are tightened around a rod 230 forming a coupling 232 allowing the connection of a flexible pipe 234 supplying compressed air or steam

  of water, constituting a fluid under pressure transmitted to the

  inside the inner tube. The posterior extremities. outer and inner tubes are clamped around the shank 230 and firmly held by a clamp 236 so that the

  fluid under pressure can not leak from the inner tube.

  The described inflatable plug is used for example for the installation and circular forming of new secondary lines, so that the end clamps described above and end cutting devices do not have to be used. An example of a method implementing the inflatable cap is as follows. The length of bent pipe required for an existing pipe is heated and rolled up at the factory using for example the steam circulation tube described

  previously. The flexible pipe 234 for pressurizing

  The plug is inserted along the piping in circular form, the inflatable plug being attached thereto, until the plug occupies the end portion.

  previous circular section piping.

  At this moment, the previously cut section of circular section piping is heated, folded with

  the inflated cap and the connected air duct

  award-winning, indoors, for on-site use.

  Figure 27 shows the introduction of the pipeline

  flexible air and the deflated cap 222 connected to it

  die, in the pipe 10 of circular shape. FIG. 28 shows the bending of the pipe 10 when the deflated plug 222 and the flexible pipe 234 are placed.

in the folded piping.

  At the place of the work, the plastic piping is heated and introduced in the folded state and

  flexible in the secondary pipe to rebuild.

  After complete introduction, the folded pipe is heated while the cap is still deflated, by circulation of water vapor in the pipework. When the entire pipe section has been heated, the plug is inflated through the flexible pipe 234 so that the plug inflates and the front end portion is flexible and still hot from the surrounding plastic tubing. the cork comes totally clog

  the anterior end of the pipe of plastic material

  tick. When the cap is inflated, the pipework is pressurized upstream of the plug for example by compressed air, and is placed in a circular section and is expanded, the air being transmitted by a flexible pipe 236 joining the torpedo plug 176 placed at the rear end of the new section of pipe, at the level of

the access opening 98.

  When the new plastic pipe has been totally circularized and expanded to the desired diameter in the existing secondary pipe 90 which has been allowed to cool, the plug 222 is deflated and removed from the new pipe section 10 by means of the pipework.

  flexible 234 air. The new secondary pipeline

  tallée is ready for use.

  Other Methods of Implementing the Inflatable Cap FIGS. 30 to 32 illustrate other methods

  of use of the inflatable cap described above.

  A slight variant of the method described with reference to Figures 27 to 29 implements the inflatable cap as a sliding plug during the process of setting the pipe in circular form. In this variant, as shown in FIG. 30, the inflatable cap 222 and

  its piping is placed in the piping 10 previously placed

  lablement in circular form and folded with the piping as indicated previously, but the plug is placed at

  about 15 cm from the anterior end 238 of the pipe

  so that the anterior end can be bent

  as closely as possible and facilitates the introduction

  in the existing secondary pipeline. The pipe

  folded earth 10, with the deflated plug 222 inside,

  is mounted in the folded state in the existing pipeline.

  The rear end of the new pipe is blocked by a torpedo plug 176, the pipe 234

  of air passing through a seal formed in the torpedo plug.

  When inflatable cap 222 is deflated, the bent tubing is internally heated with water vapor along its length to be flexible. The flexible pipe 234 of air, where it leaves the torpedo plug 176, is tightly sealed and a clamp 240 is placed on the flexible pipe 30 cm behind the rear end of the torpedo plug. When the new bent pipe is hot, the inflatable cap is inflated. In addition, the new plumbing folded between the inflated cap 222 and the torpedo plug 176 is pressurized by compressed air injected through the torpedo plug by the pipe 236 of compressed air. Pressurizing the pipe pushes the inflated plug 222 which slides toward the anterior end 238 of the new pipe until it is stopped by contact of the clamp 240 with the trailing end of the torpedo plug. At this time, the front end, like the rest of the piping that

  has been installed, is totally in the form of

  lar. The inflated cap 222 is then deflated and extracted

  of the piping that has just been installed.

  FIG. 32 illustrates another method implementing the inflatable plug for plugging new piping, placing it in circular form and dilating it in an existing secondary conduit or another conduit.

  giving access to only one end.

  In this process, the new piping is introduced

  in the secondary pipe in the folded state by one of the introduction techniques described above, and without forceps at the front end or inflatable cap for the total or partial closure of the downstream or anterior end. However, at least three meters of additional length of bent tubing of material

  plastics remain exposed at the access end of the

  existing secondary education. The folded piping is heated inside with steam so that it is flexible over its entire length. When it is hot, an external clamp 242 is applied to the folded pipe about 3 m downstream of the torpedo plug 176. The upper section of about 3 m of plastic pipe between the clamp and the torpedo plug is then put in circular form by steam injection of the

  236 in the torpedo plug and in the section

  3 m upper section of the bent pipe. The 3 m section of circular shape can then cool in a circular state.

  The torpedo plug 176 is then removed and a

  Inflatable chon 222 is introduced at least partially.

  inflated so that introduction is facilitated in

  the section of circular section of the new pipe.

  The torpedo plug 176 is reintroduced at the end of the circular section of new piping, the flexible pipe 234 from the inflatable plug passing through

  him. The clip 242 is then removed from the new pipe.

  terie and the inflatable cap 222 is deflated. The new piping is heated internally by the steam along its length so that it is flexible. When the new piping is hot, the inflatable cap 222

  is partially inflated. The internal pressure in the new

  The existing piping, which can be applied by compressed air or steam, is increased and the partially inflated plug 222 is introduced into the new piping which, at this time, is partially unfolded and partially circular. When the inflatable cap 222 reaches the downstream or anterior end of the new tubing, it is fully inflated to block the end. The new pipework is then pressurized by a fluid, put in completely circular form and cooled and thus stabilized in circular form. When the new pipe has hardened, the cap 222 is deflated and pulled out of the pipework under

totally circular shape.

  Seal at the far end of the piping A method and a device also allow the tight closure of the space between the new

  piping of circular section and the existing piping

  aunt, where the pipes intersect another

  opening, for example a manhole or other pipe-

  crocheted. An example of a pipe intersection is at the downstream end of a building sewer where it

leads into a main sewer.

  The seal is simply a compressible rubber sleeve surrounding the secant end of the new folded tubing. It has for example a thickness of 3 to 7 mm, but it can be any reasonable thickness. It has for example a length of 30 to 60 cm, but it can have

any desired length.

  When the anterior end of the new pipe-

  Folded terie is installed and made accessible, for example at a manhole, the sleeve can be slid on the folded end of the new piping

  before this end is put into circular form

  lar. Then, while putting the end of the pipe-

  in a circular form, the sleeve also comes under

  circular shape. The new piping is dilated

  during the circular forming operation until the rubber sleeve is intimately compressed between the new piping and the existing piping with formation of a seal. When the remote and inaccessible downstream ends of the building sewers are to be sealed, a different process is used. A rubber sleeve-coated with an adhesive is then used. The front end of the new bent pipe is heated, unfolded and shaped

  circular before introduction into existing piping.

  The adhesive coated sleeve is applied to the circular end, and the end is bent with the sleeve. The new folded piping is then introduced into the

  existing piping, by implementing one of the procedures

described previously.

  The use of the expandable cap previously described

  This is the preferred method of circularizing and expanding the far end to be sealed. In the case of such a plug, the expansion and consequently the seal are better and

  safer than with the other methods described.

  Method of extracting a replacement thermoplastic piping that has been installed out of an existing underground conduit As indicated above, it is preferable that the thermoplastic piping 10 be made in the form of

  folded as shown in Figure 8. After cooling

  In this folded form, the thermoplastic piping retains a shape memory property if

  although it tends to return to the folded form when

  that she is warmed up and released. This property of

  shape memory in the folded state can be used advantageously

  for the extraction of a damaged section of

  piping of an existing underground conduit.

  When thermoplastic piping deteriorates

  must be removed from the inside of an existing pipe

  the deteriorated piping is heated by circula-

  live steam and, where appropriate, also outside the

  laughing. When it is hot, the damaged section of pipe-

  terie that needs to be removed collapses by resuming its original folded configuration. This sagging and bending can be accelerated by connecting a vacuum pump inside the piping so that its internal pressure is reduced. After crushing and bending, the hot plastic tubing can be removed from the existing pipeline by a pulling winch

  a fixed cable and at an accessible end of the pipe-

crushed earth.

  Heating and shaping of thermoplastic piping before introduction The heating of the thermoplastic piping folded so that the introduction is facilitated, especially when the pipe or the existing piping has elbows or when the new piping must descend into a small vertical deep hole , has a great importance. Several pre-introduction heating methods have been described, including the use of a heating box or a long steam circulation tube. Another method involves heating the interior of the existing pipeline into

  which the thermoplastic piping must be introduced

  pick. In this process, a short section of piping

  having a steam connection is connected to the end

  existing piping that needs to be repaired. A fabric closure member at the rear end of the steam circulation pipe section is wrapped around the new folded pipe as it advances through the pipe connection.

  piping for introducing water vapor into the pipe

  existing pipeline so that the new piping is heated

  fairy during his introduction. This process can also be used advantageously with the other described heating methods. The rigid thermoplastic piping in folded and flattened form as shown in FIGS. 3 and 8 is also important because this shape gives the piping

  some properties that do not have other pipe-

  teries that can be crushed totally or partially

  only in order to reduce the cross-sectional dimensions

  and allow the introduction into existing piping. First, the folded and flattened shape represented,

  when heated and flexible, can be stored

  moderately and with a small footprint, in short or long sections, on a coil. The reel itself can be used for storage, reheating and introduction

piping in a conduit.

  Then, the form of piping represented,

  it is heated and flexible, can be introduced into a pipe having a net bend from a small vertical access opening, for example a manhole, and it can be installed around sharp bends of the

  existing pipeline itself. For example, a pipe

  rigid polyvinyl chloride compound having a wall thickness to diameter ratio within the ranges

  above, when it is flattened and folded to the

  tion shown in Figure 3 or 8 and heated to a state

  flexible, has a ratio of the minimum radius of curvature to the di-

  external meter in the circular state between 1 and 2.

  Thus, a rigid tube of polyvinyl chloride of 10 cm

  diameter, when it is supple, flattened and folded as

  can be seen in figure 3 or 8, can pass in a curve

  having a radius of between 10 and 20 cm, depending on the thickness

  wall, without damaging the walls of the pipe-

  crocheted. Such a minimum radius of curvature can not be

  obtained with other known forms of

  rigid plastics when in a flexible state.

  Third, despite the previous properties

  after heating and in the flexible state, the hose shapes

  folded teries of Figures 3 and 8 can easily resume-

  circular configuration and harden to be rigid and strong enough to withstand

  hydraulic external pressures and exerted by the ground.

  Thus, the thermoplastic piping installed according to the in-

  vention is truly a replacement pipe and not

  a coating of existing piping deteriorated.

  Of course, various modifications can be made by those skilled in the art to the methods and apparatus which have just been described solely as examples.

  non-limiting without departing from the scope of the invention.

Claims (14)

  1. A method of installing a replacement pipe formed of a substantially rigid thermoplastic material at ambient temperatures, in an existing pipe, characterized in that it comprises: the transport of a new pipe (10a) which has been manufactured in a folded and crushed state of reduced size so that the piping retains a shape memory property for this folded form, the maximum dimension of the folded pipe is less than the internal diameter of the existing pipe, this transport being carried out under the folded and crushed shape towards an access opening (98) to an existing pipe (90), heating a section of the new pipe when it is in folded and crushed form so that it takes a flexible state in the longitudinal direction,   the introduction of the anterior end of the new   piping in the existing piping when it is in the heated flexible state, positioning the new piping in the existing piping,   putting the new piping in circular form   from its folded form so that it has a   tubular form, by applying heat and a pressure   the new piping folded and crushed, and the cooling of the new piping to   that it is stabilized to its tubular form.   2. Method according to claim 1, characterized in that the existing pipe is a pipe   secondary (90) connection to a main pipe   blade, and the new piping is introduced into the secondary pipe from an access point (98)   to the mainline (92) and the new pipe-   is placed in the existing pipeline with a   pulley device and cable (158) so that the application   cation of a pulling force at a first end of a cable from the access opening, in the direction away from the main pipe, causes the front end of the new pipe to be drawn to the pipe main, by a second end of the cable. 3. Method according to claim 1, characterized in that it comprises reducing the flow of fluid that can flow through an opening formed at the front end.   the new piping before the application of a pressure   internal connection intended to restore the new piping   form, so that the pressure can rise in the new   piping and that a hot fluid can circulate along the new piping, inside it,   and the injection of a hot fluid into the new pipe-   from the posterior extremity at a temperature and   at a pressure that is sufficient for the new pipe to   terie be dilated in the circular state from its folded state and crushed.   4. Method according to claim 3, characterized in   what the flow of fluid circulating at the anterior end   the new piping is limited by plugging the anterior end with an inflatable and foldable plug (222) supported inside the new piping folded and crushed.   5. Method according to claim 1, characterized in that the new pipe is manufactured in folded form and crushed by extrusion of the thermoplastic material of the pipe to a hot plastic state by a die (118) so that it takes a tubular form of desired size, in advance of the resulting thermoplastic tubular material in the plastic state, before any significant cooling, by the openings (138) of a series of plates   (128), the openings (138) being of a size   and a configuration such as to cause folding, shaping and crushing of the tubular plastic material into a predetermined folded form,   while the plastic is subjected to a vacuum   tiel, at a temperature higher than that which gives a 263'0185   shape memory property to the thermoplastic material, then cooling the pipe folded and crushed   when it is drawn into the calibration plates and   beyond these so that the pipework hardens in folded and crushed form, by reheating the piping   folded and crushed so that it is longitudinally flexible-   but at a temperature lower than that which modifies the shape memory characteristics of the thermoplastic material, and by placing the flexible tubing in folded and crushed form at a storage state in   which tubing forms layers.   6. Process according to claim 1, characterized in   the new piping is put into circular form   by the application of heat and internal pressure in sufficient quantities that curved portions (78) are formed in the new piping at the locations corresponding to secondary pipe connections (74), so that the curved portions are positioned, part of the new piping being removed at a bulged portion so that an access opening   a secondary pipe connection is formed.   7. Method according to claim 1, characterized in   what it includes putting the circular form of the   anteriority of the new piping, the fixation of a   expandable sleeve sealing around the anterior end   circle of the new pipe, the folding of the anterior end before the introduction of the new   piping, and after positioning the new pipe-   the heating, circulating and expansion of the new piping so that the sealing sleeve is intimately compressed between the new   piping and existing piping.   Apparatus for installing a replacement piping in existing piping, characterized in that it comprises: a storage device (142) for a section of a substantially rigid thermoplastic tubing of replacement   having an anterior end and a posterior end   in a flattened and crushed state of reduced diameter, this   device retaining thermoplastic piping sensi-   rigidly rigid, the piping then being bent and arranged in layers, the storage device comprisinga chamber surrounding the stored piping, a device (140) for heating the interior of the chamber; enclosure so that the rigid piping is put in a flexible state,   a device for extracting the anterior end   pipe folded and crushed in a flexible state outside the enclosure,   a device for introducing the anterior end   of the replacement piping in the existing piping while the replacement piping is in the hot and flexible state, and   a device (222) for applying pressure   designed to expand the replacement piping from its folded and crushed state to a circular state in the piping   existing device, this device comprising a device for reducing   placed at the anterior end of the scratch piping.   and intended to allow the passage of a heated fluid   along the piping folded and crushed so that the pressure   internal dimension of the pipe section is increased by transmitting a hot fluid to the pipework from its posterior end.   9. Apparatus according to claim 8, characterized in that the replacement thermoplastic piping has been manufactured in the folded and flattened state, so that it keeps   a shape memory property corresponding to this state.   Apparatus according to claim 8, characterized   in that the pressurizing device (222) com-   carries a flexible and non-elastic tubular casing (24)   closed at the anterior end, a tubular elastic bladder   inflatable inner liner (226) placed in the envelope, the bladder being expandable under the action of a fluid under   pressure so that the envelope takes a tubular   circular section, and a connecting device   positioned at the posterior end of the bladder and for connecting the interior of the bladder to a source of a fluid under pressure. 11. Apparatus according to claim 8, characterized in that the pipe in folded and crushed form has been folded and crushed over its entire length and has a section in which a first domed and rounded portion 82 is formed on one side and a first and a second limb (83, 84) is connected to the rounded rounded portion,   the first and the second branch (83, 84)   have curved free ends (85, 87) of rounded shape which delimit fluid passages (86, 88) along the entire length of the folded pipe, and one leg (83) is longer than the other (84) so that the curved end of the shorter branch is disposed behind the curved end of the longer branch and covers this curved end, so that the total thickness of the bent pipe is reduced to a minimum.   12. Process according to claim 1, characterized in   the piping is formed of polyvinyl chloride.   13. Apparatus according to claim 7, characterized in that it comprises a device (152) for heating an end portion of the replacement pipe to a flexible and deformable state so that the introduction of a plug   fluid flow rate at the end is easily bedded. -   14. A method of extracting a section of a new substantially rigid thermoplastic pipe which has been   installed in existing piping, the new pipe-   terie having been manufactured in folded and flattened form so that it retains a memory property of this folded and flattened form, characterized in that it comprises: heating the new pipe section to a temperature such that the pipe is flexible and start   to resume at least partially the folded and flattened   with the dimensions smaller than the internal diameter of the existing piping, and the extraction of the new piping in folded and at least partially flattened form, out of the existing piping, with maintenance of the new piping at the flexible state.