SE469573B - REPLACEMENT BEAMS AND KITS AND EQUIPMENT MAKE MANUFACTURING AND INSTALLING PIPES WITH MEMORY BEHAVIOR FOR A REDUCED FORM - Google Patents

Description

469 575 2 may possibly collapse due to external pressure of some order of magnitude, such as pressure exceeding approx. 27.56 kPa, if any part of the existing pipe is torn off.

Both U.S. Pat. No. 4,394,202 and U.S. Pat. U.S. Pat. No. 2,794,758 also describes processes for inserting flexible pipes or hoses into an existing pipeline such as a lining membrane for this pipeline. The former patent describes a method for fitting the flexible pipe into the existing pipeline by using an expandable short section of adhesive-coated rigid plastic. The processes of both of the above patents have the same disadvantages as mentioned above with respect to the other prior art processes using flexible membrane material, in that they lack the necessary hoop strength to withstand external soil and hydraulic pressures.

Other. has proposed the insertion of a rigid pipe inside the existing pipeline which is in need of repair. In the published British application no. 2,084,686, for example, it is proposed that an oversized round rigid plastic pipe be flattened or otherwise reduced at the work site and then inserted cold and rigidly into the existing pipeline through a large excavation at an inspection well. After insertion, the plastic pipe is expanded by utilizing heat and internal pressure. The plastic pipe expands towards the existing pipe.

According to British patent no. 1,580,438, an existing tube laid in the ground is lined with a plastic liner or insert tube and more particularly made of a plastic material such as polyethylene or polypropylene with a plastic memory. The liner or insert tube is made in a non-round, "U" shape to fit inside the existing tube, then inserted in its non-round shape into the existing tube and then expanded against the existing tube into a round condition under heat and pressure. 469 575 3 Den. published the EPC patent application. no. 0.000,576 proposes the insertion of a semi-rigid plastic pipe insert into an existing pipe.

The semi-rigid plastic tube has sufficient ring strength to withstand all or at least some of the external pressures that can be exerted against it. a. Repair of crooked pipelines and pipelines accessible only from one end Most of the above and other known prior art processes which use rigid or semi-rigid pipes for insertion into an existing underground pipe have a common disadvantage: on due to their rigidity or principal rigidity, they must be inserted into straight or almost straight, existing pipelines. This means, for example with respect to sewers laid in the ground, that such known processes are limited to use in sewer mains or trunks as these usually have straight pipeline sections between inspection hatches. Most, if not all, of these known processes are unsuitable for use in repairing the numerous sewers for buildings extending from the sewers to buildings. Often such side tubes have bends or bends that a semi-rigid plastic tube will not get through or past. Furthermore, such side lines are not normally accessible. through inspection hatches ~ at either end. and thus known liner or replacement pipe installation methods that require inspection hatches or other access at both ends become too expensive. In most replacement pipe installation processes in underground pipes, large excavations must be made at one end of the side pipe to be repaired or re-lined, in order to provide space for the insertion of the straight, rigid plastic pipe. Such a large excavation next to a building served by the side line, or at the other end. where the side line crosses the trunk or main line, is often impractical and usually expensive. 469 573 4 Furthermore, most known processes for re-feeding or repairing existing, underground pipelines require access to the pipeline section to be repaired, at both ends of the section. This is not possible with a side line that by definition crosses a main line at a point that is usually not accessible through an inspection hatch.

For the above reasons, the known re-lining and repair processes for underground pipelines are simply not useful for building sewers. b. Repair of sewer trunks Another disadvantage of using known processes for repairing and lining existing pipeline sections crossed by sewer lines for buildings, by using straight, rigid or semi-rigid pipes is that once the pipe or hose is in place in the existing pipeline section, it is very difficult to locate the exact locations where the service side lines cross the main pipeline so that passage openings can be accommodated in the replacement pipe for passage to the service side lines.

This applies in particular if the replacement pipe has sufficient thickness and thus sufficient ring strength to withstand typical hydraulic pressures and earth pressures per se.

For the above reasons, there is a need for improved methods, devices and tools that would make it possible to repair existing, underground pipeline sections, and in particular sewers for buildings and other pipeline sections that have bends and bends, and pipeline sections that cannot easily be made accessible from both ends of the pipeline section to be repaired.

Accordingly, the basic objects of the present invention are to achieve the following: 1. A ru; and improved replacement pipeline product for installation in an existing grounded pipeline, which is particularly suitable for use in the repair and replacement of existing non-straight building sewers, and mains or trunks crossed by building sewers ; 2. A new and improved method of manufacturing a repair and replacement pipeline product particularly suitable for installation in existing, underground pipes that are not straight or crossed by side service pipelines; A method of installing a new pipeline section or a replacement pipeline section in an existing underground pipeline, and in particular one that is not straight or crossed by sewer lines for buildings; 4. An apparatus and tool for the manufacture of a replacement pipeline product as above; A device and tool for the installation of a pipeline product as above in an existing pipeline laid in the ground, and in particular such a pipeline which is not straight or which is crossed by side service pipelines; and 6. A device and tool for reshaping a new thermoplastic pipe section or a thermoplastic replacement pipe section installed in an existing underground pipe, and in particular a building sewer, after the new pipe section or replacement pipe section has been inserted into a folded state, by transforming it into a stable rounded shape inside the existing pipeline.

The present invention relates to a new and improved repair and replacement pipeline product particularly suitable for installation in an existing pipeline laid in the ground, such as a sewer for buildings, with bends and bends, and a series of closely related methods, devices and devices. tools for manufacturing the product, installing the product in an existing pipeline whether it is straight or curved, and transforming the product into a rounded shape after it has been inserted into an existing pipeline in a compressed or folded state. The product, the processes, the device. and. the tools of the present invention are particularly intended for use in the installation of the product in sewers for buildings and other existing underground pipes which are accessible from only one end of the pipeline or which have bends or bends or which are crossed by side pipes.

According to one aspect of the invention, a replacement pipeline product consists of a thermosetting plastic material such as PVC, primarily extruded and shaped into a unique folded and flattened shape so that it retains a folded memory when reheated so that it can be easily wound up for storage. and use, so that it has a reduced cross-sectional dimension for easy insertion into an existing, underground pipeline, so that it can be inserted into deep pipelines without excavation or damage to the plastic material through inspection hatches, cleaning hatches or other small vertical openings, and around sharp corners , and so that a hot fluid, despite the flattened, collapsed state of the product, can pass through it to heat its entire length.

According to another aspect of the invention, the above-mentioned plastic pipe product is installed in an existing, curved side pipe, for example by reheating the plastic pipe to a flexible state, and by subsequently pulling the hot, flexible and folded plastic pipe into the existing side pipe with towline and either a block arrangement temporarily anchored at the junction between the side line and the trunk, or with a cable drum from the nearest inspection hatch in the trunk. The folded installed pipe is heated over its entire length by passing a hot fluid through it, its front end being plugged or throttled, and a fluid, such as air, being introduced under pressure at the other end to reshape and expand the pipe into a rounded shape. Thereafter, while continuing to apply internal pressure to the reshaped, rounded tube, it is allowed to cool to thereby stabilize in its rounded shape.

According to another aspect of the invention, various means are provided for plugging or throttling the front end of the plastic tube to allow a hot fluid to pass therethrough while it is folded and to still allow expansion and transformation of the folded tube into a round shape by applying an internal fluid pressure.

According to another aspect of the invention, means are provided for closing or sealing an inlet end of the folded pipe to allow the folded pipe to be subjected to internal fluid pressure when inserted into an existing underground pipe.

According to another aspect of the invention, there is provided a unique block-and-line assembly which can be slid through a service side line to its intersection with a main pipeline and which can be temporarily anchored there by maintaining tension against both ends of the line. One end of the rope is anchored to the front end of the folded pipeline to be installed; then the opposite end of the rope is pulled to pull the folded plastic tube into the existing side pipe while it is in a heated, flexible state.

According to another aspect of the invention, various means for heating the opposite ends and various other portions of the plastic pipe product are provided to allow reworking or reprocessing of selected portions of the pipe for clamping, inserting plugs or for giving the entire length of the pipe a sufficient flexibility for insertion into an existing pipeline that is not straight.

The above and other objects, features and advantages of the present invention will become apparent upon study of the following detailed description taken in conjunction with the accompanying drawings. In the drawings: Fig. 1 shows a cross-sectional view of a conventional thermoplastic pipe, such as a PVC pipe used in accordance with the invention, and in its expanded, rounded state; 469 573 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 8 is a perspective view of the thermoplastic tube according to - fig. 1 and a device for reducing the tube from its round state to a flattened and folded state for storage on a roll; a cross-sectional view of the thermoplastic tube of Fig. 2 after it has been folded, taken along line 3--3 of Fig. 2; a schematic view illustrating a process for installing the folded and wound thermoplastic 2 and 3, the thermoplastic tube according to Fig. in a drain stem, from an inspection hatch, the tube being stored on a roll and reheated for installation in the the pipeline laid in the ground to be restored; a schematic view, in section, illustrating a detail of the device for expanding the folded thermoplastic tube according to Figs. 2 and 3 and for rounding it after it has been inserted into the existing main pipeline in the manner shown in Figs. 4; a schematic view, in cross section, illustrating an alternative construction for expansion and rounding of the folded thermoplastic tube after its insertion into an existing pipeline; a schematic cross-sectional view through a typical sewer line for buildings extending from a building it serves to a main sewer line, illustrating a method of installing the thermoplastic pipe in an existing building sewer line, in accordance with the invention; a cross-sectional view through a preferred embodiment of the thermoplastic tube according to Fig. 1, when this is Figs.

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Fig. 10 ll 12 13 14 15 16 469 573 9 folded for installation j. An existing pipeline laid in the ground; a schematic vertical projection of an apparatus for manufacturing the thermoplastic tube of Fig. 1 in a folded form, as shown in Fig. 8; a vertical projection of the calibration device in the device according to Fig. 9, on an enlarged scale, as used for the manufacture of the thermoplastic tube in the form shown in Fig. 8; a vertical projection of a single calibration plate in the calibration device according to Fig. 10, seen from the line II-II in Fig. 10; a plan view of a folded end portion of the thermoplastic tube of Fig. 8, with an end clamp mounted for use in retracting the tube into an existing pipeline and for throttling the tube end to allow the tube to be subjected to internal pressure for expansion purposes; a sectional view taken along line 13-13 of Fig. 12; a somewhat schematic plan view of a line-and-block device according to the invention, which is also shown in Fig. 7, for retraction. the folded thermoplastic tube in which, according to Fig. 8, in a service side line, the device is shown in its working position; a view similar to Fig. 14 but with the device of Fig. 14 in a collapsed condition for insertion into a service side line; a somewhat schematic side view in vertical projection of the device according to Figs. 14 and 15; 469 573 Fig. 17 Fig. 18 Fig. 19 Fig. 20 Fig. 21 Fig. 22 Fig. 23 Fig. 24 10 a side view 'in vertical projection' of a plugging tool used in plugging one end of a length of the thermoplastic tube shown in Fig. 8, after the end has been rounded, for use in transferring fluid, heat and fluid pressure to the interior of the thermoplastic tube; a vertical projection of the front end of the tool of Fig. 17; a view of one end of the thermoplastic tube with 17 and 18 inserted into the tube and clamped in place by means of a chain plugging tool according to Fig. clamping means; a view of the chain clamping means of Fig. 19 prior to its application to the tube and plug of Fig. 19; a cross-sectional view taken along line 21-21 of Fig. 19 and illustrating the chain clamping tool of Figs. 19 and 20 as it clamps the end of the thermoplastic tube against the plugging tool of Figs. 17-19; a somewhat schematic longitudinal section through. a front end portion of the thermoplastic tube of Fig. 8 with the end clamping means of Figs. 12 and 13 attached to the end of the tube and with the rest of the tube expanded and rounded, and with a cutting tool according to the invention inserted into the end portion of the rounded tube for cutting the clamped end from the rest of the tube; a sectional view through the tube and cutting tool of Fig. 22, taken along line 23-23 of Fig. 22; a somewhat schematic side view in vertical projection of an end heating device used in heating Fig. 25 Fig. 26 Fig. 27 Fig. 28 Fig. 29 Fig. 30 Fig. 31 - reworking of the end portion, 469 575 ll of an end portion of the thermoplastic tube for the heater tool being shown installed on a folded end portion of the thermoplastic tube of Fig. 8; a perspective view of an inflatable end plug tool used to plug or throttle the end portion of the thermoplastic tube instead of the end clamp member of Figures 12 and 13, to allow expansion and rounding of the folded thermoplastic tube; a shortened vertical projection, partly in section, of the inflatable tube of Fig. 25; a schematic view illustrating installation of the inflatable plugging tool of Figs. 25 and 26 in the thermoplastic tube when it is in an expanded and rounded condition; a schematic view similar to Fig. 27 but illustrating the tube of Fig. 27 after it has been refolded with the inflatable plug in an emptied condition therein; a schematic view illustrating the use of the inflatable plugging tool of Figs. 25 and 26 during installation of the thermoplastic tube in a service side line; a schematic view illustrating another use of the inflatable plugging tool of Figs. 25 and 26; a schematic view further illustrating the use of the inflatable plugging tool of Figs. 25 and 26 in accordance with the process illustrated in Fig. 30; 469 573 Fig. 32 Fig. 33 Fig. 34 Fig. 35 Fig. 36 Fig. 37 12 is a schematic view illustrating a further use of the inflatable plugging tool of Figs. 25 and 26 for expanding and rounding the folded thermoplastic the pipe after it has been inserted into an existing pipeline laid in the ground; a schematic view of a main pipeline section and an intersecting service side pipe, illustrating an alternative method of pulling the thermoplastic pipe of Fig. 8 into a service side pipe to be provided in a schematic 'view of' an end portion of the folded thermoplastic pipe; according to Fig. 8, illustrating a method of releasing the tow line from the front end of the pipe after it has been inserted into a pipe laid in the ground; a schematic view similar to Fig. 34 and illustrating still another method of releasing the tow line from the thermoplastic pipe after it has been inserted into an existing, underground pipe; a cross-sectional view through the intersection of a main pipeline and a service side pipeline after the thermoplastic pipe of Fig. 8 has been installed and expanded within the main pipeline to be repaired, and illustrating a method of inserting and cutting an opening through the newly installed thermoplastic. the pipe for re-establishing the connection between the service side line and the main pipe; a schematic side view in vertical projection illustrating a method and apparatus for folding a thermoplastic pipe which has been manufactured around, for insertion into an existing, underground pipe; Figs. 38A-E are schematic cross-sectional views taken along lines 38A-38A and 38A, respectively. 38E-38E in Fig. 37; Fig. 39 is a somewhat schematic side view in vertical projection of a releasable end clamp and attached tow line and release line, for use in clamping the front end of the folded pipe of Fig. 8 during its installation; Fig. 40 is a plan view from above of the end clamp of Fig. 39; and Fig. 41 is a top plan view of the release wedge portion of the clamp of Fig. 39.

Repair of Sewer Trunks and the like Referring primarily to Fig. 1, reference numeral 10 denotes a type of pipe used to rebuild, repair or replace ground pipe sections, such as sewer pipes or the like, according to the present invention.

A characteristic of the pipe is that it is formed of a thermoplastic material such as PVC, and more specifically a material which is normally rigid and thick-walled to have sufficient annular strength to withstand external earth pressures and hydraulic pressures to which it could be subjected. when it is in the earth. Nevertheless, such a thermoplastic pipe can be made flexible when heated to temperatures of, for example, 93.3 ° C or more, in the case of a PVC pipe. A feature of the tube 10 is that it is structurally rigid or solid at typical ambient temperatures above ground and in the ground, but becomes flexible and machinable into various shapes when heated or reheated. Another characteristic of such a thermoplastic material is that it has a memory; i.e. if it is manufactured in a special shape, such as a round tube shape and then heated and flattened or folded and then cooled to stabilize in its folded shape, and then reheated without compression or restriction, it will strive to return to its 469 575 14 original round tubular shape. Conversely, if the tube is initially made, for example, in a compressed or folded form, as shown, for example, in Figs. 3 and 8, then heated and under internal pressure expanded to a rounded shape and later cooled and stabilized in its rounded shape, it will strive after returning to its original folded form if the latter is heated without compression or restriction. This memory aspect of the thermoplastic tube is utilized to advantage in certain aspects of the present invention.

A conventional and easily accessible pipe of the type useful in the practice of the present invention is a polyvinyl chloride (PVC) pipe with standardized dimensional ratios (outer diameter / wall thickness) in the range of 13 to 65 which is currently available for buried in the ground. pipelines such as drainage pipes, water pipes, etc. Although, in the most preferred embodiment of the present invention, the thermoplastic pipe is made in a folded condition, as shown in Fig. 8, in the manner described with reference to the device of Fig. 9. -11, at least certain aspects of the invention may also be practiced in the use of a thermoplastic tube made in a tubular shape or a round shape. Fig. 2 illustrates the device 11 for reshaping the conventional PVC pipe 10 which has been manufactured in a round shape.

Fig. 3 illustrates a cross-section through the pipe after it has been reshaped by flattening and folding using the device according to Fig. 2. More specifically, the PVC pipe is heated in any conventional manner, such as by means of a heating means 11a, which may be a thermostatically controlled steam box or a housing containing thermostatically controlled electric heating elements. By passing the originally round tube 10 through the heating box 11a, the tube is heated to a temperature sufficient to make the tube plastic or flexible.

Thereafter, it is preferably flattened or folded in a folding device 11 to reduce its overall cross-sectional dimension so that it can be easily drawn into a pipeline laid in the ground having the same or only slightly larger inner diameter than the original outer diameter for the thermoplastic tube.

The reduced folded thermoplastic tube is illustrated at 10a in Fig. 3. Although the unit 11 in Fig. 2 schematically illustrates a tube folding means, a practical tube folding device and method is illustrated in more detail with reference to the device of Figs. 37 and 38A. -E. There, it is seen that the round tube 10, after passing through the heater 11a, is first flattened by means of a pair of opposite flattening rollers 60, 61 and then passed under a folding wheel 62 while being progressively supported by three different sets of folding rollers 63, 64, 65. The pair of folding rollers 63 are arranged in cooperation with the folding wheel 62 to start folding the tube 10 into a U-shape.

Thereafter, the three folding rollers 64 continue the folding process by being arranged in a half U-shape for cooperating with the folding wheel 62. Finally, the set of four folding rollers 65 is arranged in a U-shape for cooperating with the folding wheel 62 in order to end the folding of the tube. 10 to a U-shape. Thereafter, the folded tube is passed through a restriction mold 66 while it is being cooled, in order to stabilize the tube in its U-shape so that it has a U-shaped memory. From the mold 66, the folded pipe can either be stored in predetermined lengths or passed through a steam pipe to be reheated and to be made flexible for insertion directly into an existing pipeline.

Alternatively, after the flattening process and before folding, the tube in its flat state can be wound in the heating box 18 shown in Fig. 4. Thereafter, the flat, rolled tube can be reheated in the heating box at the workplace, and then pulled from the heating box and folded as described. earlier, just before insertion into the pipe to be rebuilt.

In some applications it may also be possible to install the thermoplastic pipe in an existing pipe in a flattened condition, in particular if the thermoplastic pipe in its round condition has a substantially smaller outer diameter than the inner diameter of the * pipe to be repaired. In most conditions, however, it is preferable for the thermoplastic tube to be installed in an existing pipeline in a longitudinally folded form, as shown either in Fig. 3, Fig. 8 or in Fig. 38E. Of all the folded shapes, however, the shape of Fig. 8 is preferred for the reasons explained below.

As mentioned earlier, the thermoplastic tube, when manufactured in a round shape, has a memory which tends to cause it to return to its round shape when reheated after folding. Thus, in the event that it is necessary to reheat the folded pipe to make it flexible for installation in an existing pipeline, the pipe will strive to return to its round shape, possibly prematurely, unless it is restricted or restrained. It is primarily for this reason that it is preferred that the thermoplastic tube be primarily made in a desired folded shape. When the folded pipe is subsequently reheated to make it flexible for insertion into an existing pipeline, the pipe will retain its folded shape until it is fully inserted into the existing pipeline and is ready for transformation into a round shape.

Whether the thermoplastic pipe is manufactured in a round or folded form, the pipe should be in a folded form when it is ready for insertion into an existing pipeline. It is also preferable that the thermoplastic tube is wound up while being heated and thus made flexible on a storage roll, such as the roll 12 shown in Fig. 4.

The roll 12 with the folded thermoplastic tube is stored in a housing or a "heat box" 18 equipped with a thermostatically controlled heater 24 for heating the interior of the heat box and thus the roll 12 for making the folded tube material 10a flexible when desired. Conveniently, the heating drawer 18 is also equipped with an air circulation system 19 to prevent heat stratification inside the heating drawer, thereby ensuring that the rolled-up roll moves va »GW. 9,573 17 is heated uniformly. The heating box 18 is suitably mounted so that it is movable and is shown mounted on the flat loading surface of a truck 20 for transport to a workplace. A smaller form of heating box can be mounted on wheels and can be moved manually for use in operating small inaccessible pipelines, such as sewer lines for buildings. In any case, either machine-driven or manually-operated means are provided for rotating the roller 12 for the purpose of winding material on the roller or unwinding it from the roller. The heating drawer 18 is equipped with an access door 21 and may also be equipped with a downwardly extending channel 22 and a roller 23 to facilitate insertion of the folded thermoplastic pipe into a pipeline laid in the ground through a vertical access opening, such as the inspection well 16 in the existing sewer line 14.

According to one aspect of the invention, the heating box 18 is transported to an opening at a work site, such as the inspection hatch 16, at a pipe section laid down in the ground, such as the drain stem 14 to be repaired. The end of the reduced pipe 10a is connected to a tow line 26 made accessible from an adjacent opening in the existing pipeline, such as another inspection hatch (not shown), and which is connected by means of a clamping means 28 to the free or front end of the new the tube. The new tube is made flexible by heating the roller 12 in the heating box 18 via the heater 24. The tow line 26 is then activated, for example by means of a winch at the next inspection hatch downstream of the inspection hatch 16, to pull the flexible, folded tube 10a from the roller 12 through the duct 22 and around the duct roller 23 and into the existing pipe 14 to the next inspection hatch. After insertion of the folded new tube, it is heated and expanded into a round or substantially round shape to provide a tube that will harden or solidify into a thick-walled, solid shape with sufficient annular strength to withstand external hydraulic and ground pressures.

Fig. 5 illustrates a method of expanding the reduced dimension tube, after it has been drawn into the original tube 469 573 18 to be restored or replaced. According to such a method, a pair of plugs 30 and 32 are inserted into the opposite ends of the folded tube when at least the ends are in a heated, flexible state. The plug 30 is installed at a distal end of the new pipe section located at the insertion end of the existing pipeline. The plug 32 is installed at the front end or pull line end of the new pipe after disconnecting the pull line.

Each of the plugs 30 and 32 is provided with a peripheral, expanding sealing member 34 provided for releasably sealing engagement with the original tube 14 and the new tube 10a.

The sealing elements. 34 are inflated via pressure lines * 36, such as air pressure lines, which lead to control means (not shown) above the ground. The plug 30 has an inlet conduit 38 therethrough for introducing an expanding medium, such as fresh steam or hot water, into the new pipe. Such a line is equipped with a suitable control valve 40 as well as a pressure gauge 42 and an overpressure valve 44. The plug 32 has an outlet line 46 which communicates with the space between the two plugs and which at 48 is provided with a suitable valve.

The newly installed, folded pipe, with the plugs inserted at its opposite ends, is then heated internally by passing fresh steam through the small channels provided at the folds of the new pipe, as shown in Fig. 8. Valve 48 at the downstream end is open so that the entire length of the new pipe is heated. The valve 48 is then closed while steam under pressure continues to be introduced through the plug 30 to pressurize the folded tube and cause it to reshape and expand into a round shape. If the new tube is made folded, it should be cooled or allowed to cool after it has taken on its rounded shape while maintaining an internal pressure, such as cooling air pressure, so that the tube hardens or solidifies in its round shape. The last step is not necessary if the pipe is made in a round shape, unless the pipe has been expanded or stretched beyond its original diameter during the transformation process (CQSSGI). If no internal channels are provided in the folded new pipe, as would be the case if the new pipe is folded completely flat, as shown in Fig. 3, the new pipe would need to be heated externally, such as by passing fresh steam through it. existing pipe, before the plugs 30 and 32 are inserted into the ends of the new pipe.

With the new pipe heated over its entire length, the plugs 30 and 32 could then be easily inserted into the opposite ends, the valve 48 would be closed and fresh steam or hot water would be introduced through the plug 30 to expand the folded pipe and transform it into a round form.

Fig. 6 shows another type of device 35 for expanding the reduced pipe. Such a device comprises a mandrel 50 with heating means 52 therein, which is capable of heating the new pipe to a flexible state. The mandrel 52 is connected to a tow line 54 or other means for pulling it through the original tube. Upon proper heating of the mandrel and by application of a traction force to the traction line, the mandrel is pulled through the original tube during expansion of the new tube to the desired diameter. With this method, of course, the tow line 54 would be inserted into the new pipe before the new pipe is folded for insertion into the existing pipeline.

A third method of heating, rounding and expanding the new pipe involves flushing hot water or steam down through the existing pipe to be repaired, along the installed but still folded new pipe, until the desired temperature is reached at the downstream end. The new pipe is then pressurized by hot water or steam and expanded under pressure to a round shape and to the desired diameter.

Example In a specific process for the reconstruction or reconstruction of a pipe, a conventional PVC pipe is obtained which has plus or minus 12.7 mm smaller outer diameter than the inner diameter of the pipe to be restored. The PVC pipe has standard dimensional ratios between wall thickness and outer diameter as previously pointed out. The PVC pipe is heated to at least 93.3-98.9 ° C and reduced to the shape shown in Fig. 3, Fig. 8 or Figs. 38E. The folded pipe is then stored on large rolls so that it can be transported by truck to the workplace. During installation in an existing pipe or pipeline laid in the ground, the new pipe is reheated, preferably in a heating box 18, to make it flexible and easily retractable substantially vertically down through a deep inspection hatch and then substantially horizontally through the existing pipeline. Once installed in the existing pipeline section, the folded pipe is plugged, heated and rounded. If desired, it can also be expanded beyond its original or nominal rounded diameter to fit snugly against the existing pipeline section.

Ways to locate sewer line connections for buildings.

An advantage of expanding the newly installed thermoplastic pipe beyond its original nominal diameter is illustrated with reference to Fig. 36, where the existing pipeline section to be repaired is crossed by at least one sewer line for a building or by some other side service line. In Fig. 36, the main pipeline 70 at 72 is crossed by a service side line 74, such as a sewer line for a building. When the new thermoplastic tube is installed in the stem 70 and rounded and expanded or stretched beyond its original rounded nominal diameter to tightly engage the inner wall of the existing stem 70, a bulge 76 is formed at the opening of the service side line into or intersection 72 with the tribe. This bulge 76 is in fact an indication of the exact location of the opening of the service side line into the trunk. By passing a TV camera through the trunk, the exact location of the bulge, and thus of the opening of the service side line, can be determined. Thereafter, a remotely controlled cutting tool 78 can be passed along the stanun to the exact location of the bulge and used 46-9 575 21 to cut the bulge 76 from the new tube 80, thereby reopening the access of the service side line 74 to the stem.

Rounding and expansion, or stretching, of the newly installed thermoplastic pipe is achieved by means of the methods described above or in the manner described below with reference to further embodiments.

Preferred shape of the folded tube Although the flattened and folded thermoplastic tubes of Figs. 3 and 38E are suitable for use in the installation processes described, the preferred shape of such folded tubes 10 is shown in Fig. 8. The thermoplastic tube 10 according to Fig. 8 is manufactured substantially in the folded form shown. It is generally a flattened tube folded along a generally curved, cross-sectional bulb, longitudinal seam or fold 82, to form a pair of superimposed legs, comprising a long leg 83 and a shorter leg 84. The long leg 83 terminates at a curved or bulbous free end 85 for defining a small longitudinal channel 86 through the folded tube. The shorter leg 84 likewise terminates in a curved or bulbous free end 87 which likewise defines a longitudinal channel 88 through the tube.

Further, the softly folded portion 82 defines a channel 89 along the inside of the rebate, from one end of the tube to the other.

The bulbous fold or crease and the bulbous ends of the legs, as described, are important in preventing the folded portions of the tube from cracking or cracking when the tube is folded, which could otherwise happen if the tube is folded flat in the manner shown. shown in Fig. 3, in particular if the pipe is thick-walled.

The ducts 86, 88 and 89 are also important in enabling steam or some other hot fluid to pass through the full length of the folded pipe for reheating and thus reshaping it after the folded pipe has been installed in an existing underground pipe. Without such access to the interior of the folds or folds of the folds, the reheating would take place through a long, slow process and be very difficult to achieve.

The folded shape of the pipe according to Fig. 8 is particularly suitable for use as a replacement pipe in the repair of sewers for buildings, such as the sewer 90 for buildings shown in Fig. 7 and which runs from an intersection 92 with a main pipe 94 and into a building 96 to be served. Installation of a replacement pipe in such sewers for buildings entails special problems due to the nature of such pipes. Firstly, such side pipes pose difficult access problems because they often run under lawns, trees and shrubs and are not accessible by means of inspection wells. Excavation of the existing side line that is in need of repair would thus be very expensive. When inserting a new side pipe into an existing side pipe laid in the ground, it is usually only practically possible to access it from a single small vertical excavation next to the building, as indicated at 98 in Fig. 7. Such an excavation leaves little space for maneuvering or for a large amount of equipment.

Second, sewer lines for buildings are usually much smaller in diameter than trunks and often have sharp bends or bends, unlike trunks which are usually straight from inspection hatch to inspection hatch. The drain line 90 for a building has, for example, a bend at 100, which makes it impossible to insert a straight, rigid pipe into the existing side pipe. In Fig. 7, the drain line 90 for the building, which is accessible via the vertical excavation 98 adjacent to the building 96, extends under a lawn 102 and to the trunk 94, at a considerable depth below one, street 104. The processes and devices to be described next are particularly suitable for solving the unique problems of installing a replacement side pipe in an existing side pipe, laid in the ground, from a single small, mainly vertical access opening. Such methods and devices utilize the fabricated shape of the folded thermoplastic tube shown in Fig. 8.

Method and apparatus for making a thermoplastic tube in folded form Referring to Figures 9, 10 and 11, the folded thermoplastic is made. the tube of Fig. 8 using a conventional plastic tube extruder 106 which extrudes into a vacuum box or suction box 108. Traction means 110 comprising a series of opposing feed rollers 111, 112, downstream of the suction box, draws the extruded and shaped material from the suction box under tension and feeding it to a steam pipe 114 for reheating to a flexible state, so that the resulting folded pipe can be wound in its folded form on a storage roll 116 which would typically be placed in the heating box 18 of Fig. 4.

A nozzle 118 and a mandrel 120 are located at the outlet of the extruder. There is a gap 121 of between 304.8 and 609.6 mm between the downstream end of the nozzle 118 and the inlet to the suction box 108.

The suction box is internally divided into three sections by means of partitions 122, 123. All three sections are filled with water to a level 124 inside the box. The first or upstream section of the box is connected to a source of negative pressure 125. Although the entire suction box is under negative pressure by such connection, a maximum negative pressure prevails in the upstream section of the box. Calibration means 126 are arranged in the first section of the suction box. The calibration means shapes and maintains the extruded plastic material in its desired, folded state as the material cools and thus hardens. The water inside the suction box serves a cooling function and a negative pressure applied to the box cooperates with the calibration means to maintain the plastic material in its desired folded form until it, by cooling, is able to maintain such a shape without being restricted or maintained. back.

With particular reference to Figs. 10 and 11, the calibration means comprises a series of calibration plates 128 arranged in a spaced apart relationship and assembled by means of mounting rods 130 and separated by means of spacers or spacers 132 between the plates, on the rods. The rods are threaded at their opposite ends and are secured by means of nuts 134. The calibration plates 128 which are closer to the inlet end of the calibration member are separated more closely together than those which are further downstream, due to the greater plasticity and flowability. for the plastic at the inlet end portion and thus the greater need to maintain the shape of the extrusion therein. part of the 'calibrator. As an add-on, the calibrator also includes a central tube 136 with openings 137 for transferring cooling water to and between the plates for faster cooling of the plastic material.

Referring to Fig. 11, each calibration plate 128 includes a precision cut aperture 138 with the exact contour shape and outer dimension of the folded tube formed and maintained in the calibration plates. Each plate 128 in the calibrator has exactly the same size and shape of the opening. When comparing Figs. 8 and 11, it should be noted that the opening 138 in the calibration plate comprises a short leg 38a corresponding to the short leg 84 of the folded tube and a long leg 138b corresponding to the long leg 83 of the tube as well as a rounded seam portion 13c corresponding to the longitudinal tube. rounded seams or folds 82.

In the manufacture of the tube of Fig. 8, a crude plastic mixture, such as polyvinyl chloride, is fed into the extruder 106 through a hopper 107 where the material is heated to a high temperature of, for example, 182 ° C, and then extruded through the nozzle 118 where the very hot plastic material the mandrel 120. meets the plastic to the desired final dimension and shape as the Nozzle and the mandrel are sized to form the desired shape on the tube. The plastic material is fed over the gap 121 and into the first section of the suction box 108 and through the calibration plates. The plates form and maintain the plastic material in the shape and dimension determined by the openings 138 of the calibration plates.

When the plastic material first enters the calibrator, it is very hot and quite liquid, and thus the calibration plates 128 are very close together at this point to maintain the desired shape. The negative pressure inside the box holds the plastic against the outer periphery of the openings 138 when the cooling water cools the plastic material. If desired, compressed air injected from a source 140 into the mandrel 120 can be passed down through the inner channels 86, 88, 89 of the folded plastic mold to ensure that the plastic does not completely collapse and to maintain the tubular shape of the folded tube. By the time the plastic material reaches the downstream end of the calibrator 126, it is substantially cooled and can retain its own shape under the stress applied by the feed rollers 110. Such rollers pull the folded plastic from the suction box into a continuous strip. From the calibration plates the strip runs through the second and third chambers in the suction box, where it progressively hardens or solidifies. When the strip 10 leaves the suction box, it is cold, rigid and substantially in the shape shown in Fig. 8. The puller 110 regulates, by pulling the strip or material stream from the extruder under tension, the wall thickness and other dimensional parameters of the folded tube.

From the puller 110, the folded strip is fed through the steam pipe 114, into which a steam source 115 feeds through an inlet opening 117 for reheating the strip to a flexible state, so that it can be wound up on the storage roll 116.

The number and distance between the calibration plates used in the calibrator is a function of the extrusion speed as determined by the peeler, and by the desired wall thickness of the finished tube. As mentioned earlier, the roller 116 of the stored, folded tube 10 "can be installed in the heating box 118 shown in Fig. 4, for transport to and use at a workplace.

Method, device and tool set for installation of thermoplastic pipe in a side pipe Fig. 7 not only illustrates a drain side pipe, as described earlier, but also illustrates a method, a device and a tool set for insertion of the folded thermoplastic pipe according to Fig. 8. in the side line. First, a vertical excavation or shaft 98 must be dug, preferably as close as possible to the building 96 served by the side line 90, to break through the existing side line 90 and to provide access thereto.

Thereafter, the length of the sideline to be repaired or replaced can be determined by inserting a flexible fiberglass rod into the sideline, during excavation, and feeding the rod through the sideline until it crosses the trunk 94. When this occurs, the length of the rod within the sideline may be marked at the access opening. and then the rod is pulled out and measured to determine the length of the plastic tube 10 required for the work. When the lengths of a series of side pipes to be repaired are known, the folded pipe 10 can be cut in advance corresponding to these lengths, either at the factory or at some other place at a distance from the workplace. Thereafter, such pre-cut lengths can be transported to the installation sites.

Alternatively, the required lengths can be cut at the workplace, from the roller 116 or 12 (Fig. 4) inside the heating box 18 transported to the workplace. If the excavations for the side pipes to be repaired are not accessible to the truck 20 on which the heating box 18 is mounted, the necessary lengths of the plastic pipe 10 can be stored on other, smaller rollers, inside smaller, wheel-mounted heating boxes (not shown) which are rolled to 469 573 27 respective excavations. A smaller "mini-heat box" 140 is shown in Fig. 7, enclosing a roll 142 of folded tube 10.

Rather than pre-measuring and cutting the required lengths of the folded plastic pipe 10 to lengths corresponding to the lengths of the side pipes to be repaired, the folded pipe 10 as an alternative can simply be heated inside the heating box 140 and fed into the existing side pipe until the new, folded tube reaches the junction with the stem 94, and is then cut at the roll.

If the folded plastic pipe 10 is pre-cut to the correct length at the factory, it can also be transported in its cut lengths to different workplaces and heated there, for insertion into the existing side pipe, in a steam pipe similar to the steam pipe 114 shown in Fig. 9. The steam pipe may be made of canvas or metal or equivalent materials, with flexible ends of fabric or equivalent xnaterial, which may. tied around the folded plastic pipe to keep the steam inside the steam pipe. Such pipes are of the lightweight type for easy transport to a workplace and can be 6.1 meters long or longer. For use in the field, a canvas steam pipe is preferred over the metal pipe and this with respect to weight.

If the drain side pipe is straight and if its access opening at the excavation is close enough to the surface or if the excavation is large enough, it may be possible to insert the required length of the folded plastic pipe 10 into the existing side pipe simply by sliding the new pipe into the existing tube until the front end reaches the stem. Often, however, this will not be possible because it is necessary for the new pipe to pass through a bend at the excavation or along the side pipe, or both parts. In such cases, it is necessary to heat the normally rigid, folded plastic pipe to make it bend longitudinally so that it can withstand the bend, and to pull the new, folded pipe into the side pipe rather than push it. Pulling the flexible, folded plastic pipe into the existing side pipe, without any access opening at the stem end of the side pipe, poses special problems which the present invention addresses.

Pulling the new side line into the existing side line from the access opening One way of inserting the new side line into the existing side line. by pulling, the use of a pulling line applied to the front end of the new side line.

This line runs around a breaker plate at the connection of the side cable and then returns to the input. to the side line. By applying a traction force: to the traction line from to the trunk, the access opening, at the excavation 98, the new pipe can be pulled along the entire length of the existing side line. This method involves the use of a special set of tools.

First, the front end of the new side conduit must be clamped closed to limit the size of the through-channels 86, 88, 89, 8, the interior of the folded tube is pressurized after it has been inserted into it as shown in Figs. the side line, while still allowing hot fluid to pass through the folded tube so that it can be heated over its entire length and thereby made flexible for expansion and rounding. To achieve this limitation and clamping at the end, an end clamping member shown in Figs. 12 and 13 is used. A side view of the end clamping member is also shown in Fig. 22. Referring to these three figures, the end clamping member 144 comprises a pair of rigid metal plates. These plates comprise an upper plate 145 and an opposite bottom plate 146. projecting nose portions 147 with aligned drawline connection holes. Both plates have forward 148 extending therethrough. Another pair of aligned holes 149 extend through the bottom plate and the upper plate behind the line hole 148. The bolt 150 also extends through aligned, drilled holes 151 through the plastic tube 10 for receiving a clamping bolt 150. 29 For installation of the end clamp 144 on the front end of the folded plastic tube 10 heats the front end of the tube to make it flexible, and this heating takes place, for example, in an end heater 152 shown in Fig. 24. The end heater 152 comprises a thin-walled, rigid tube 154 which is closed at a end by means of an end plate 156 having a central inlet port 157 with a steam hose connection 158. The opposite end of the heater comprises a flexible sheath 160 of canvas or other suitable fabric bonded to the tube 154 at the connecting band 162. The free end of the sheath 160 may be knotted or is tied around the folded plastic tube 10 in such a way that steam is allowed to flow out at the jacket connection 164 to the tube, so that whole. the end portion of the tube is heated to a desired temperature by injecting steam into the tube through the connection 158. The length of the tube 152 may be approximately 0.61 meters for most purposes, although it may be longer and shorter depending on the application.

After the front end of the tube 10 is made flexible, the plates of the end clamp 144 are applied to the end of the tube, and the bolt 150 is inserted through the bolt holes 151 and tightened so that the opposite plates 145, 146 press an intermediate portion of the folded tube into a flatter condition. reduction of the dimensions of the channels 86, 87, 89 at the end of the folded tube. It should be noted that the width of the clamping plates 145, 146 is substantially narrower than the total width of the folded tube 10, so that channels 89, at the crease or seam, and 86 at the end of the long leg are not completely closed when applying clamping force to the folded tube. Thus, when the clamp is applied, fluid can still pass completely through the clamped end of the tube, but still the channels are small enough to achieve a build-up of an internal pressure within the folded tube for expansion and rounding of the tube.

The described end heater is also useful for other purposes as will become apparent from the following description. 469 573 30 Releasable end clamp Another type of end clamp that can. used instead of the end clamp 144, is a releasable end clamp 250 shown in Figs. 39-41. The clamp 144 has the disadvantage that it is not removable from the front end of the pipe 10 when it is inserted into a blind pipeline, but that the clamped end of the pipeline is cut off by using a special remotely activated cutting tool shown in Fig. 22. and 23 and described below. However, a releasable end clamp 250 can be remotely released from the clamped end of the new pipe when desired and can be pulled from the existing pipeline by means of the rope.

The releasable clamp 250 includes an upper claw 252 articulated at 254 at a lower claw 256. The lower claw 256 includes a front end tongue 258 with a towline hole 260 extending therethrough, for attaching a towline 262. The claws 252, 256 have gripping ends 263, 264 to grip and compress a front end portion 266 of the folded plastic tube 10 when this portion is hot and pliable.

A bolt 268 extends through a large opening 270, larger than the bolt head 269, and through a aligned, smaller bolt hole 272 in the lower claw 256. The bolt hole 272 is smaller than the nut 273 and the head 269 on the bolt 268. A fork-shaped release wedge member 276 has parallel arms 277, 278 defining a groove 280 and joined to a vertically wedge-shaped body 282. A flexible release rope 284 is attached to the body 282 by passing through the hole 286 of the body. The wedge member 276 is constructed wedged between the head 269 of the bolt 268 and the upper surface of the upper clone 252, with the arms 277, 278 extending below the head and with the notch 280 receiving the shaft of the bolt. Thus, the bolt head 269 is pulled toward the arms 277, 278, rather than through the large opening 270 in the upper claw, when the bolt is tightened to clamp the ends 263, 264 of the claws toward the tube 10. 469 573 31 To release the clip from the new tube after the pipe has been pulled into the existing drain side line using the tow line 262, and after the new pipe has been rounded, except for the clamped end, the release line 284 is pulled. This pulls the wedge member 276 away from under the bolt head 269 (or nut 273 if the nut end of the bolt is located above the upper clone), allowing the bolt head to fall through the large opening 270 in the lower clone 256, thereby allowing the claws to open to release the pipe end. The wedge element and clamp can be pulled from the side wire, or the trunk. by utilizing their respective tow lines.

Drum-and-Flap Frog Another tool used in pulling the new, folded side line into the existing side line from the access opening 98 is a drum-and-line member. referred to herein as a "frog", shown in Figures 14-16. The frog 152 includes a line break disk 154 rotatably mounted within a disk housing 156 on a shaft 157. Mounted at opposite sides of the open rear end of the disk housing are a pair of angle legs 158. Each leg includes a front leg section 158a and one formed as a unit therewith. posterior leg section l58b. Extending rearwardly from the rear leg sections 145b are a pair of flexible steel leg guide bands 160, curved inwardly at their rear ends 161. Swivel joints 162 between the legs 158 and the housing 156 are spring loaded to press the legs outwardly as shown in Fig. 14. However, the legs can be pivoted inwardly to the positions shown in Fig. 15 to allow the legs and thus the entire assembly to move through the side conduit.

A pair of generally triangular arms 164 are articulated at the connection points between the front and rear leg sections l58a, l58b at spring-loaded articulations 166. The spring-loaded joints 166 press the arms 164 toward their extended positions shown in Fig. 14, perpendicular to the rear leg sections. 158b, when in their extended positions according to Fig. 14. However, the arms 164 can be lowered towards the spring pressure and to their folded positions shown in Fig. 15, again to allow the frog to move through a side joint to their destination. A tow line 168, both ends of which return to the access opening 98, is passed around the breaker plate 154.

With its tow line 168 attached, but with both ends of the line going back to the access opening 98, the frog is inserted into the existing side line and pushed through it using a flexible fiberglass push rod (not shown). When the frog reaches the point of intersection between the side line and the trunk, and with the housing 156 and its connected lens disc inserted into the trunk, and also with the front legs 158a entering the trunk, the arms 164 spring outward from their positions shown in Fig. 15 to their positions in Fig. 14. showed open. modes. In the open position of the legs, the rear end sections 158b and their connected leg straps 160 press against the inner wall of the existing side conduit. At this point, both ends of the towline 168 are pulled to firmly anchor the frog at the branch point between the side conduit and the trunk.

While tension is further applied to the towline to hold the frog anchored in place, one end of the towline is applied to the end clamp 144 (Figs. 12-13) or the releasable end clamp 250 (Figs. 39-41). The other end of the rope, which is still located at the access opening 98, is pulled to pull the heated, flexible, folded plastic tube 10 through the side conduit and around the bend 100 until the leading end of the folded tube 10 reaches the branch between the side conduit and the stem at frog 152. Traction can be applied to the rope 168 to achieve this, either by hand or by using a manually operated or motorized winch 170 (Fig. 7) at the access opening 98. Through the triangular shape of the arms 164, traction or tensile stress prevented from being applied. towards the line 168, the frog from tilting up or down.

After the new, folded plastic tube reaches the frog in the trunk, the cable connection at the end clamp of the tube is released and an end 469 573 33 of the rope is pulled through the rope disc so that the frog falls into the trunk. The line is then pulled out of the service line from the entrance opening and the frog can be retrieved from the trunk at a later time by using conventional recovery methods. At this point, the folded plastic tube 10 is fully inserted into the side line to be repaired, with its clamped front end at the stem. The folded plastic tube is now ready to be reheated and expanded into a round old existing service side line.

Before discussing the expansion and rounding process used in service side lines, mention should be made of the method and means used to release the tow line 168 from the end clamp 144 so that the line can be pulled through the frog. This can be achieved in a number of ways, as shown in Figs. 34 and 35.

Fig. 34 illustrates what can be called a line release by abrasion. In this method, a "slack" end 68a of the towline 168 is attached to a rope or cord 172 which has a relatively low strength or strength and which can rupture and which in turn at 173 is taped to a front portion of the folded tube 10 which shall be inserted in the existing side line. From its slack end, the tow rope 168 is laid loosely in loops through the rope hole 148 in the end clamp, as indicated by the loose loops or loops 168b, 1680, and then passed through the rope disc of the frog.

The pull end of the rope remains at the access opening to the side line. If an end clamp is not used, the line hole 148 can be drilled directly through the folded front end of the plastic tube. When the winch at the access opening pulls the rope through the frog to winch the folded new tube into the existing side conduit, the cord 172 maintains moderate tension on the slack end of the rope l68a. When the front end of the folded new tube reaches the frog, the pull end of the line is pulled abruptly so that the cord 172 ruptures and releases the slack end of the line l68a through the line hole 148, so that the line can be "taken home".

Fig. 35 illustrates a similar line release method which may be referred to as the hand held line release. In this method, the slack end portion of the rope 168 is again passed twice in a loose loop through the rope hole 148 at the front end of the folded new tube 10 to form the double loops or loops 68b, 68c. Thereafter, the tow line 168 is passed through the existing side line 90 to the frog and back to the entrance opening. The slack portion 16a of the line must be longer than the length of the new tube 10 to be inserted. When the winch pulls the new tube into the existing side conduit, a moderate tension is maintained on the slack end l68a of the rope, allowing the folded new tube to be pulled into the side conduit. When the new tube is properly inserted into the existing side conduit, the slack end 16a of the rope is released at the inlet opening so that it is allowed to be pulled free from the front end of the newly inserted tube through the rope opening 148.

Method and device for expansion and rounding of a folded pipe inside a side pipe With the folded, new pipe in place inside the existing side pipe, this is ready to be expanded and rounded to replace the existing side pipe as a functioning service side pipe. . At this time, the front end of the folded new tube 10 is already confined by an end clamp 144 or 250 so that the folded tube can be pressurized internally by means of fluid and so that hot steam or any other fluid can still be allowed. pass through this. This makes it possible to heat the entire inner length. of the folded tube to a flexible state for expansion. At this time, of course, the rear end of the newly inserted folded tube is also covered to allow the introduction of hot steam or other fluid into the tube for heating and expansion. Such a cover member, or plug, is shown in Figs. 17-21.

A generally conically shaped plug, termed a "torpedo plug" 176, includes a generally conical front portion 178 with a mouth 180 at its front end. The conical portion 178 extends rearwardly to a short cylindrical portion 182 which is closed or 469 573 covered by a rear end plate 184. The plate 184 includes an inlet port 186 and a hose connection 188 for connecting a steam or hot water supply hose so called fluids under pressure can be introduced into the interior of the folded tube. Other hose connections may also be provided through the end plate 184, such as an air hose connection, for expansion of the pipe by utilizing air pressure or for maintaining air pressure in the expanded pipe as it hardens or solidifies in its expanded, rounded state.

With the rear end of the folded tube 10 heated, as by utilizing the end heater 152 described earlier, to make it flexible, the conical portion of the torpedo plug 176 is driven into the rear end of the tube 10, as shown in Fig. 19. until the end cover plate 184 abuts the end edge. on the new tube, thereby expanding the end of the new tube to a rounded shape corresponding to the outer diameter of the cylindrical plug portion 182. An adjustable chain clamping device 190 is used to clamp the expanded end portion of the new tube against the cylindrical portion 182 of the torpedo plug to seal the tube against the plug.

Details of the chain clamping device 190 are shown in Figs. 20 and 21.

The chain clamping device comprises a clamping plate 192 with a curved surface 193 intended to engage with the tube. At the convexly curved outer surface of the plate a fork 194 is mounted, between the legs of which a nut element 195 is rotatably arranged. The nut member 195 receives a threaded rod 196 having an end 197 adapted for engagement with a tool for rotating the rod. A tensioning chain 198 is connected to the opposite end of the rod. The chain is preferably a transmission chain or a bicycle chain or the like. The chain is adapted for adjustable connection to an anchoring support 199 on the outer surface of the clamping plate 192.

With the end of the tube 10 heated and flexible and with the torpedo plug 176 inserted at this end, the clamping plate 192 is placed on the rounded tube end and the chain 198 is wound around the cylindrical tube end, 469 573 36 tightened as tightly as possible by hand and anchored to the anchoring support 199. Clamping pressure is then applied by rotating the threaded rod 198 in a direction of shortening the effective length of the clamping chain 198, using a turning tool attached to the corresponding end of the rod 197. It is important that the clamp is easy to tighten as the plastic tube tends to deform when it is heated, and the clamp must be tightened in place during the heating and rounding process of the new pipe.

With the torpedo plug clamped in place at the rear end of the newly inserted pipe, a steam hose is connected to the plug connection 188. Hot steam is forced through the length of the folded pipe, more specifically through the small channels thereby, thereby allowing the full length of the pipe to heat. At the same time, the restriction or throttling effected by means of the end clamp at the front end of the folded tube allows the tube to be placed inside under a pressure of up to approx. 172.25 kPa. When the tube is heated and pressurized, it expands and rounds to its cylindrical shape over its entire length, except at its clamped end portion.

Once the new pipe has been expanded and rounded to its desired dimension, usually against the inner wall of an existing side pipe, the plastic pipe is allowed to cool while maintaining internal pressure, for example by introducing pressurized air, thereby allowing the pipe to stabilize in its new rounded form. Once the new tube has stabilized, the chain clamp is released from its rear end and the torpedo plug is removed.

Removing the Clamped End of the New Tube The next step is to remove the end clamp and the still folded and clamped end portion of the new tube from the remaining, rounded portion of this tube. This is accomplished by cutting the clamped and folded front end from the expanded and rounded new tube in the manner shown with reference to Figures 22 and 23.

Figures 22 and 23 show a separating means intended for cutting away the folded and clamped front end of the expanded and rounded tube 10 in the existing tube. The separating means comprises a motor-driven cutting tool 200. The cutting tool comprises a small, high-speed electric motor or air motor 202 housed in a cylindrical motor housing 204 with a substantially smaller diameter than the inner diameter of the rounded plastic tube 10. A flexible air hose or power cable 20 supplies power to motor 260. remote source at the entrance opening to the existing service side line. A motor drive shaft 208 carries a rotor 210 at which a pair of inserts or bits 212, 213 are rotatably mounted at pivot joints 214 adjacent the outer ends of the rotor.

The motor housing 204 is encapsulated in an inflatable rubber sleeve 216 which, when expanded, centers and anchors the cutting unit in place within the rounded plastic tube. A flexible air supply hose 218 supplies air under pressure to inflate the sleeve 216. Although the shown bites or inserts 212, 213 are made of steel, they could also be made of chain or rope. They are designed and intended to be extended outward by centrifugal force as the rotor 210 rotates, to strike and cut the plastic tube 10.

In operation, the cutting unit 200 is pushed down through the new plastic pipe 10 after the pipe has been installed and rounded. The insertion can be effected by means of a flexible fiberglass rod and with the rubber sleeve 216 emptied of air. The cutting device is pushed into the existing side line until it reaches the recessed and clamped front end. At this time, the sleeve 216 is inflated to anchor and center the cutting unit within the rounded plastic tube. With the sleeve inflated, the motor 202 is activated by supplying it via the air hose or power cable 206. 469 573 38 The motor rotates the rotor 210 to activate the bits or inserts 212, 213 ~ until the blades cut off the clamped and folded end of the plastic tube. The separated end falls into the trunk and can later be recovered using conventional methods.

After the front end of the pipe is cut off, the sleeve 216 is emptied of air and the cutting unit is taken back from the rounded plastic pipe simply by pulling the air hose 218 and the power cable 206 from the inlet end of the new pipe. The new side line is now installed in the existing side line, and after being connected to the portion of the side line leading into building 96 (Fig. 7), it is ready for use.

Alternative Methods and Devices for Installing and Expanding the New Pipe in an Existing Side Pipe Fig. 33 illustrates an alternative method of pulling the folded plastic pipe 10 through an access opening 98a and into an existing side pipe 90a which crosses a main pipeline 94a at a branch point 92a. At a distance from the branch 92a, the stem 94a has an inspection hatch 216 for access into the stem. A cable winch or cable drum 218 is stationed at the inspection hatch 216. The front end of a tow line 220 is inserted into the existing side conduit 90a at the access opening 98a and pushed down along the side conduit to the branch 92a by means of a flexible fiberglass rod, the front end of which is provided with a gripper to grip the front end of the towline.

The front end of the push rod is also curved so that, when it reaches the branch, it can be guided around the sharp corner and into the trunk. At this point, the push rod continues to push the towline 220 through the stem, as shown at 220a, until the front end of the towline reaches the inspection hatch 216. The front end of the towline is attached to the winch cable at 219. The rear end of the towline 220, which is still at the access opening 98a to the side line 90a, is connected to the front end of the folded tube 10 using the line release methods described previously. After being heated, for example, in the heating box 18 to make it flexible, the new tube is pulled into the existing side conduit 90a by winching the line 220 using the winch 218 at the inspection hatch 216. This retraction continues until the front end of the new tube Reaches the branch 92a. Thereby, the tow line 220 is released from the front end of the new pipe by using one of the techniques previously described. The new tube is now ready for expansion and rounding within the existing side line 90a, using either the previously described rounding methods or any other method that will be described.

Method for rounding a pipe by means of an inflatable plug Another method and device for expanding the newly installed plastic pipe inside an existing service side line is shown in Figs. 25-29. This method is called the method that uses an inflatable plug. The inflatable plug 222 used in this method is shown in Figs. 25 and 26. It is used in place of the end clamp 144 (Figs. 12-13) or the end clamp 250 (Figs. 39-41) to seal or restrict and limit it accessible front end of the new plastic pipe so that this pipe can be pressurized, rounded and expanded. The plug is adapted to be able to maintain at least an air pressure of 172.25 kPa, to expand to an outer diameter with the size of the inner diameter of the rounded new pipe, but not to rupture if it is not limited or held back by the new pipe. The plug should also be designed to withstand a temperature exceeding 93.3 ° C.

The inflatable plug could be constructed of a single layer of flexible material if a suitable material corresponding to the above specifications could be found. However, no such suitable material has yet been found. For this reason, a 2-layer construction of the plug is currently used. The plug is composed of an outer tube 224 of canvas or other fabric which is folded, closed and sewn together at its front end 225. The outer tube 224 has an expanded diameter corresponding to the desired inner diameter of the new tube when rounded. The rear end 226 of the canvas tube remains open. An expandable inner tube or bladder 228 of rubber is located inside the canvas tube. The total length of the plug can vary from approx. 0.3 meters to 6.1 meters depending on the application. The rear ends of the outer canvas tube and the inner rubber tube are gathered around a tube shaft 230 which provides an air hose connection 232 for an air or steam supply hose 234 for supplying pressurized fluid to the interior of the inner tube. The rear ends of the outer and inner tubes are assembled around the tube shaft 230 and are tightly connected by a band clamp 236 to prevent leakage of pressure fluid from the inner tube.

The inflatable plug described is typically used in the installation and rounding of new service side lines, so that the previously described end clamps and end cutting devices do not have to be used. A typical method of utilizing the inflatable plug is the following: The required length of the folded plastic pipe for a given, existing service side line is heated and rounded in the Workshop by using, for example, the previously described steam pipe.

The hose 234 for pressurizing the plug is inserted through the length of the rounded plastic tube, with the inflatable plug attached, until the plug is placed at the front end portion of the rounded plastic tube.

At this point, the pre-cut length of the rounded plastic tube is reheated and folded over with the airless plug and the connected air hose folded in for use in the field. Fig. 27 shows the insertion of the air hose and the connected airless plug 222 into the rounded plastic tube 10. Fig. 28 illustrates the folding of the tube 10 with the airless plug 222 and the hose 234 inside the folded tube.

\ O 575 4 6 41 At the workplace, the plastic pipe is heated and inserted into the side pipe that..should be rebuilt while it is folded and flexible. When fully inserted, the folded plastic tube, with the plug still empty, is heated by passing steam through the tube. When the full length of the installed plastic pipe has been heated, the plug is inflated via the air hose 234 for expansion of the plug and thus the still hot, flexible front end portion of the plastic pipe 10 surrounding the plug, this to completely plug the front end portion of the plastic pipe.

After the plug is inflated, the plastic pipe is placed upstream of the plug under pressure, for example by means of compressed air, rounded and expanded, the air being supplied by means of a hose 236 leading into the torpedo plug 176 at the rear end of the new pipe, at the access opening 98 .

After the new plastic tube is completely rounded and expanded to a desired diameter within the existing side conduit 90, and then allowed to cool, the plug 222 is emptied of air and pulled out of the newly rounded tube 10 via its air hose 234.

The newly installed plastic side cable is now ready for operation.

Other Methods of Utilizing the Inflatable Plug Figs. 30-32 illustrate some other methods of utilizing the inflatable plug just described.

A slight variation of the method illustrated in Figs. 27-29 is the use of the inflatable plug as a sliding plug during the pipe rounding process. According to this variation, with reference to Fig. 30, the inflatable plug 222 and its air hose are installed in the pre-rounded plastic tube 10 and folded with the tube as before, but with the plug placed approx. 15 cm or so from the front end 238 of the tube, this front end being allowed to fold as compactly as possible to facilitate insertion into the existing side conduit. The folded tube 10, with the airless plug 222 inside, is installed folded as before in the existing side line. The rear end of the new tube 469 573 42 is plugged by means of a torpedo plug 176, with the air hose 234 extending through a seal in the torpedo plug.

With the inflatable plug 222 airtight, the folded tube is heated internally by means of steam over its entire length to make it flexible. The air hose.234, where it extends from the torpedo plug 176, is tightened and a clamp 240 is placed on the hose 30 cm or so behind the rear end of the torpedo plug. When the folded, new tube is hot, the inflatable plug is inflated. The folded new tube, between the inflated plug 222 and the torpedo plug 176, is further pressurized with compressed air which is led through the torpedo plug via the overhead line 236. A pressure load of the new tube forces the inflated plug 222 to slide towards the front end 238 of the the new tube until it is stopped by the abutment 240 of the clamp against the rear end of the torpedo plug. At this point, the front end, like the rest of the newly installed pipe, will be completely rounded. The inflated plug 222 is now emptied of air and pulled from the newly installed pipe.

Fig. 32 illustrates another method of utilizing the inflatable plug 222 to plug, round and expand the new tube within an existing side conduit or other conduit accessible from only one end.

According to this method, the new pipe is inserted into the side pipe in the folded state by using one of the previously described insertion techniques and without the front end clamp or inflatable plug for sealing or limiting its front or downstream end. At least approx. However, 3 meters of extra length of the folded plastic pipe is left exposed at the access end to the existing side pipe. The folded tube is steam heated internally to make it flexible over its entire length. When hot, an outer clamp 242 is applied to the folded tube approx. 3 meters downstream of the torpedo plug 176. Then the upper 3 meters or so of the plastic pipe between the clamp and the torpedo plug is rounded by introducing steam from the line 236 through the torpedo plug and into the upper 3 meters of the folded 469 573 43 pipe. The rounded 3 meters of the tube are then allowed to cool in this rounded state.

The torpedo plug 176 is now removed and the inflatable plug 222 is inserted into at least a partially inflated condition to facilitate insertion into the rounded section of the new tube.

The torpedo plug 176 is reinserted at the end of the rounded section of the new tube, with the air hose 234 from the inflatable plug extended therethrough. Now the clamp 242 is removed from the new tube and the inflatable plug 222 is emptied of air. The new pipe is steam heated inside again and over its entire length to make it flexible again. When the new tube is hot, the inflatable plug 222 is partially inflated. The internal pressure inside the new tube, which may be vapor pressure or air pressure, is increased, and the partially inflated plug 222 is propelled through the new tube, which at this point is partially unfolded and partially rounded. When the inflatable plug 222 reaches the downstream or front end of the new tube, it is fully inflated to plug the end. The new tube is now placed under fluid pressure, completely rounded and cooled so as to stabilize in its rounded state. When the new tube has hardened, the inflated plug 222 is emptied of air and pulled from the completely rounded tube.

Pipe seal at the distal end A method and means are likewise provided to seal the space between the new rounded pipe and the existing pipe wherever these pipes cross another opening, whether it is an inspection hatch or another pipe. A typical pipe branch would be at the downstream end of a sewer line for buildings, where it enters a sewer trunk.

The seal is simply a compressible rubber sleeve that surrounds the intersecting end of the folded, new tube. It is typically 6.35 mm to 3.18 mm thick but can have any reasonable thickness. It is typically 30.5 cm to 61 cm long but can have any desired length. 469 575 44 When the front end of the folded new tube is installed and accessible; as with an inspection hatch, the sleeve can be slid over the folded end of the new tube before. this end is rounded.

Then, during rounding of the pipe end, the sleeve is also rounded. The new tube is expanded during the rounding process until the rubber sleeve is compressed tightly between the new tube and the existing tube, to form the fluid tight seal. Another method is used to seal the remote and inaccessible downstream end of sewers for buildings. The adhesive-reinforced sleeve is applied to the rounded end, and the end is folded again with the sleeve applied. Thereafter, the folded, new tube is introduced into the existing tube, using one of the previously described processes.

The use of the expandable plug described above is the preferred method for rounding and expanding the distal end to be sealed. With such a plug, the expansion and thus the seal becomes more complete and safer than with the other methods described.

Method of removing an installed thermoplastic replacement pipe from an existing pipeline laid in the ground As previously pointed out, it is preferable that the thermoplastic pipe 10 be manufactured in the folded form shown in Fig. 8. Once cooled and hardened in such a folded mold, the thermoplastic tube retains a memory for such a mold, which memory strives to return it to such a folded mold whenever it is reheated and is unrestricted or unrestrained.

This memory for its folded shape can be used to advantage when removing a damaged section of such a pipe from an existing pipeline laid in the ground.

To remove the damaged thermoplastic pipe from inside an existing pipeline, the damaged pipe is heated by passing fresh steam through it and, if possible, around its outside. When the damaged pipe section to be removed is hot, it collapses --b Cï \ 9 573 45 to its original, folded shape. This folding and refolding can be accelerated by connecting a vacuum pump to the interior of the pipe, to lower its internal pressure. Once collapsed and folded, the hot plastic pipe can be pulled from the existing pipeline by means of a cable drum with the tow line connected to an accessible end of the collapsed pipe.

Heating and shaping the thermoplastic tube for insertion Heating the folded thermoplastic tube to facilitate its insertion is important, especially when it must bypass curves in the existing tube or pipeline, or when the new tube must be fed down through a small, deep vertical hole.

Several methods of heating for insertion have been described, including the use of a heating drawer or a long steam pipe.

Another method is to heat the inside of the existing pipeline into which the thermoplastic pipe is to be inserted.

According to this method, a short pipe section is connected with a steam connection to the rear end of the existing pipe to be repaired. A canvas closure on the rear end of the steam pipe section is wound around the folded, new pipe as it is fed through the steam pipe connection into the existing pipe to heat the new pipe during its insertion. This method can also be used to advantage together with other described heating methods.

The flattened, folded shape of the rigid thermoplastic tube shown in Figs. 3 and 8 is also significant in that such a shape gives the tube certain properties which cannot be achieved with other tubes which can be caused to collapse or partially collapse only for the purpose of to reduce their overall cross-sectional dimensions for insertion into an existing pipe. The flattened, folded form shown can only, when the tube is heated and flexible, be stored comfortably and compactly in long or short lengths on a roll.

The roller can in turn be used for storage, reheating and feeding of the pipe into a pipeline. 469 575 46 Second, when the pipe is heated and flexible, the pipe shown can be inserted into a pipeline around a sharp bend from a small vertical access opening, such as an inspection hatch, and this can be installed around sharp corners in the existing pipeline itself. . For example, a rigid PVC pipe with a typical wall thickness to diameter ratio within the aforementioned range, when flattened and folded to the unique shape shown in Fig. 3 or 8, and heated to a flexible condition, will have a ratio minimum bend radius to rounded outer diameter of between one and two. In other words, a typically rigid 102 mm diameter PVC pipe, when flexible, flattened and weighted as shown in Figs. 3 or 8, can handle a bend having a radius of between 102 mm and 204 mm, depending on on wall thickness, without damaging the pipe walls. Such a minimum bending radius is impossible to achieve with other known forms of rigid thermoplastic tubes when in their flexible states.

Third, the folded tubular shapes of Figures 3 and 8, despite the above properties when heated and flexible, can be easily reshaped into a round shape and hardened to make them structurally rigid and strong enough to withstand external earth pressures and hydraulic pressures. . Thus, the installed thermoplastic tube of this invention is a genuine replacement tube or replacement tube and not merely a liner for a damaged, existing tube.

Having now described the principles of my invention with reference to what are currently a number of preferred embodiments and variations thereof, it should be apparent to those skilled in the art that the invention may be modified in a variety of ways without departing from these principles.

The invention thus encompasses the preferred embodiments and all modifications, variations and equivalents which fall within the spirit and scope of the appended claims.

Claims (25)

469 573 47 PATENT REQUIREMENTS 1. l. Replacement tube product (10a) for insertion into an existing pipeline (14), known as a length of substantially rigid thermoplastic tube in a reduced shape (10a) such that the tube retains a memory for such a reduced tube. shape and can be made flexible and expanded into a main tube shape (10) with the desired dimension, the maximum dimension of the tube in the reduced shape (10a) being smaller than the dimension when the tube is in a tube shape (10). Replacement tube product according to claim 1, characterized in that the thermoplastic tube consists of polyvinyl chloride. Replacement pipe product according to claim 1 or 2, characterized by a pipe length of a thermoplastic plastic material such that the pipe at ambient temperature is substantially rigid and at a predetermined elevated temperature is flexible and expandable into a main pipe shape (10) with a desired dimension, that the tube has a flattened and longitudinally folded shape (10a) comprising first (83) and second (84) legs joined together at a rounded, bulbous, longitudinally folded portion (82), that the first (83) and other (84) legs of the folded tube (10a) terminate at rounded, bulbous free ends (85, 87) defining fluid channels (86, 88, 89) through the length of the folded tube, and that a (83) of said leg is longer than the other (84) so that the bulbous end (87) of the shorter leg (84) rests behind and in an overlapping relationship with the bulbous end (85) of the longer leg (83) for miniaturization. mering of the total thickness of the folded tube (10a). 4. A replacement pipe product according to claim 3, characterized in that the pipe has a memory for such a flattened and folded shape. 469 575 48 5. A method of making a thermoplastic tube in a reduced mold (10a), tubular material in a hot and plastic state is extruded characterized by thermoplastic through a nozzle (118) to form the plastic material into a tubular mold (10) of desired size, that the resulting hot tubular plastic material while being maintained in the plastic state is fed through a calibration member (126) sized and shaped to form and hold the hot tubular plastic material in the desired reduced shape (10a). ) and that the thermoplastic material is cooled in its reduced form (10a) to cure in this reduced form. 6. A method according to claim 5, characterized in that the hot plastic material is subjected to a partial negative pressure in the calibration means (126). 7. A method according to claim 5, characterized in that the tubular plastic material is formed into a flattened and longitudinally folded shape (10a). 8. A method according to claim 5, characterized in that the tube is heated in reduced form (10a) to make the tube flexible and that the flexible tube in reduced form is wound on a storage roll (116). 9. A method according to claim 8, characterized in that the heating is effected by applying steam (115) to the pipe. A method according to claim 5, characterized in that the resulting hot, tubular thermoplastic material in the plastic state and before any substantial cooling thereof is fed through the openings in a series of calibration plates (128) in the calibration means (126), in which the openings are dimensioned and shaped to collapse and reduce the tubular plastic to a predetermined reduced shape (10a) while subjecting the plastic material to a partial vacuum and a temperature above that which will give the thermoplastic material a memory, by the collapsed and folded tube then being cooled as it is pulled through and from the calibration plates (128), to cause the tube to harden in the reduced form, by the reheated and folded tube to be made longitudinally flexible, below the temperature that will change the memory properties of the thermoplastic material and that the flexible tube in its collapsed oc h folded mold (10a) is placed in a storage state in which the tube is layered or arranged in turns. 11. ll. A method according to any one or more of claims 5-10, characterized in that the thermoplastic tube is made of polyvinyl chloride. Device for manufacturing a length of rigid thermoplastic tube in a reduced mold and having a memory for the reduced mold, characterized by extrusion means (106) for extruding a thermoplastic material in a hot, plastic state to a length of tubes (10) having a substantially tubular cross-section of the desired size and of calibration (126) and cooling means (122, 123) for forming and maintaining the extruded thermoplastic material in a desired reduced shape (10a) where all dimensions are smaller than the tubular shape (10). Device 'according to claim' 12, characterized by pressure means (125) for maintaining the shape of the extruded material in the calibration means (126). Device according to claim 13, characterized in that the pressure means (125) is a negative pressure means connected to the outside of the pipe. A method of installing a replacement pipeline (10) of substantially rigid thermoplastic material at ambient temperature, in an existing pipeline (14), a new pipe being provided at an access opening to the existing pipeline, in a reduced form (10a) as is expandable into a tubular shape (10) with a desired outer diameter substantially the same as the inner diameter of the existing pipeline (14), a length of the new tube, while it is in its reduced shape (10a ), heated to a longitudinally flexible state, a front end of the new pipe (10a) is inserted into the existing pipeline (14) while in this heated, flexible state, the new pipe (10a) is placed inside the existing pipe (14), the new pipe is rounded from its reduced shape (10a) to a pipe shape (10) by applying heat and internal pressure to the new pipe and the new pipe is cooled to stabilize it. the tube shape (10), k a use of a new pipe made in a flattened and reduced mold (10a) so that the pipe retains a memory for such a reduced mold in which the maximum dimension is smaller than the inside diameter of the existing pipeline (14). A method according to claim 15, wherein the existing pipeline is a side pipeline (90) connecting to a main pipeline (94), characterized in that the new pipe (10) is inserted into the sideline (90) from an access point (98). ), in the direction of the main pipeline (94) and by placing the new pipe (10) in the existing pipeline.by means of rope and pulley means (152, 168) so that a pull in a first end of a rope (168), from the access opening (98), in a direction away from the main pipe (94), will cause a second end of the rope member to pull the front end of the new pipe (10) in the direction of the main pipe (94). Method according to claim 15, characterized in that the possibility of fluid flowing from an opening at the front end of the new pipe (10) is limited before the application of internal pressure to reshape the new pipe (10), for to enable a build-up of fluid pressure inside the new tube (10) and to allow hot fluid to pass internally through the length of the new tube, and by a heated fluid being subsequently introduced into the new tube (10) from a rear end hence, at a temperature 69 573 ~ ... 51 and a pressure sufficient to expand the new tube from its reduced shape (10a) to a round shape (10). Method according to claim 17, characterized in that the flow of fluid from the front end of the new tube (10) is limited by plugging the front end by means of a flexible, collapsible and inflatable plug (176) inserted inside the collapsed and folded new pipe. 19. A method according to claim 15, characterized in that the collapsed and folded tube (10a) is reheated to make it flexible longitudinally, but below the temperature which will change the memory properties of the thermoplastic material and in that the flexible tube in its collapsed and folded form (l0a) is placed in a storage state in which the tube is layered or arranged in turns. Method according to claim 15, characterized in that the new pipe (10) is rounded with sufficient heat and sufficient internal pressure to form projections (76) in the new pipe (10) corresponding to the location of side connections (74), in that the protrusion portions (76) are located and by a portion of the new tube being removed at the protrusion portion (76) to form an access opening for a side connection. Method according to claim 15, characterized in that the front end of the new pipe (10) is rounded, in that an expandable sealing sleeve is fitted around the rounded front end of the new pipe, in that the front end is folded again before insertion of the new pipe and that the new pipe, after placing it in position, is heated, rounded and expanded to compress the sealing sleeve tightly between the new pipe and the existing pipeline. Device for installing a replacement pipe inside an existing pipeline (14), with storage means (20) for a substantially rigid thermoplastic replacement pipe, which has a front end and a rear end, in one. reduced mold (10a), storing the substantially rigid thermoplastic replacement tube in a reduced mold (10a) in which the tube is curved and stored on itself, the storage means comprising an enclosure (18) for enclosing the stored tube, heating means (24) heating the interior of the enclosure (18) to transfer the rigid tube to a flexible state, means (26) for pulling out the front end of the flexible, collapsed and folded tube (10a) from the enclosure (18), insertion means for inserting the the front end of the replacement tube (10) in the existing pipeline (14) while in a heated and flexible condition and pressure means (30, 32, 38, 40) for expanding the inserted replacement tube from its reduced shape. (10a) to a rounded state (10) in the existing pipeline (14), including restriction means (32) at the front end of the collapsed pipe to allow passage of heated fluid through the length of the collapsed pipe. and folding the tube (10a) to increase the internal pressure of the tube and means (30) for supplying a heated fluid into the tube from its rear end, characterized in that the stored tube is a length of substantially rigid thermo plastic replacement tube (10a) made in a flattened and folded, reduced state and expandable to the desired round state (10), whereby the tube retains a memory for the reduced state. Device according to claim 22, characterized in that the pressure means comprises a flexible and inelastic, tubular jacket (222) closed at a front end (225), an inner tubular, elastic, inflatable bladder (228) inside the jacket, wherein the bladder is expandable under fluid pressure to cause the jacket to assume a rounded tubular shape, and connecting means (236) at a rear end of the bladder for connecting the interior of the bladder to a fluid source (234). Device according to claim 22, characterized in that the replacement tube in the reduced shape (10a) has been caused to collapse and fold along its length and has a cross section with a rounded, onion-shaped portion (82) at a side and first (83) and second (84) legs joined to the rounded bulb portion (82), the first (83) and second (84) legs terminating at rounded, bulb free ends (85, 87) defining fluid passages (86, 88, 89) over the length of the folded tube and one leg (83) being longer than the other (84) so that the bulbous end (87) of the shorter leg (84) lies behind and in overlapping relationship. with the bulbous end (85) of the longer leg (83), thereby minimizing the overall thickness of the folded tube (10a). Device according to one or more of Claims 22 to 24, characterized in that the replacement tube is made of polyvinyl chloride. Device according to any one or more of claims 22-25, characterized by end heating means (152) for heating an end portion of the replacement tube (10) to a flexible, machinable condition to facilitate insertion of a end plug (32) limiting fluid flow.