NL9600014A - Intake manifold with removable baffles - has upper and lower manifolds assembled forming plenum chamber in fluid communication with intake - Google Patents

Abstract

The intake manifold has a lower manifold unit with lower runner portions and a lower plenum portion and an upper manifold unit with an intake manifold opening surrounded by a carburetor mounting flange, upper runner portions and an upper plenum. When the upper and lower manifold units are assembled the upper and lower plenum portions form a plenum chamber is fluid communication with the intake opening and the upper and lower runner portions form a number of intake runners between the plenum chamber and the respective cylinders each of which has an outlet port and a surrounding passageway side wall. The unit is constructed so that each outlet port is aligned in fluid communication with a respective cylinder intake port. Baffle members are removably mounted as part of the assembled unit for directing flow of the fuel mixture and form a relatively uninterrupted extension of each of the respective flow passageways.

Description

Method and device for installing a replacement pipe in an existing underground pipe.

The invention relates to improvements and their methods and apparatus for installing a replacement pipe section within an existing underground pipe, such as a pipeline section to be repaired or replaced. The invention relates in particular to the installation of a replacement pipe section within main sewers intersecting. connections, within other main pipelines, crossing side-pipe pipelines, within pipeline sections that may include curves and sharp bends, and within yet other pipeline sections that are intersected by house connections, the connections of side piping being difficult to find after a new piping section is installed within the existing pipeline section.

Several methods have been proposed for repairing underground pipelines such as sewer lines and the like, whereby the existing pipeline remains in place underground, by installing a flexible membrane or plastic sheathing within the existing pipe or by inserting a new plastic pipe into the existing pipe. pipe.

In one known method, pipes are fed with a flexible plastic such as polyethylene. According to this method, the cladding is installed through input wells spaced along the pipeline, making the process expensive.

In another method, for example, shown in U.S. Pat. Nos. 3,927,164 and 4,064,211, a flexible tube is turned inside out and inflated and blown into one-pipe section from one end of the section. This method is expensive because special equipment, extensive heating and expensive materials are required.

The above methods, and most others, use a flexible or semi-flexible coating that is not capable of withstanding significant external hydrostatic pressure or ground pressure. The existing pipe can therefore not be properly repaired, since the coating, when a part of the existing pipe is broken off, may collapse due to external pressure of any size, such as pressures exceeding 27 kPa, for example.

United States Patent 4,394,202 and United States Patent 2,794,758 disclose methods of introducing flexible tubing into an existing pipeline as a casing membrane for that pipeline. U.S. Patent No. 4,394,202 describes a method of attaching the flexible tube to the existing pipeline using an expandable short section of adhesive coated stiff plastic. The methods of U.S. Pat. Nos. 4,394,202 and 2,794,758 have the same disadvantages as mentioned above with respect to other methods using flexible membrane material in that they provide the necessary hoop strength to resist external ground and hydraulic pressures. breakfast.

Others have suggested introducing a rigid pipe within the existing pipeline to be repaired. For example, in published British application 2,084,686, an oversized round rigid plastic pipe is flattened or otherwise reduced in size at the site and then cold and stiffly introduced into the existing pipeline through a large excavation at the site of a manhole. expanded using heat and internal pressure. The plastic pipe is expanded against the existing pipe.

According to British Patent 1,580,438, an existing underground pipe is lined with a plastic casing, which is made of a plastic material such as polyethylene or polypropylene with a plastic memory (plastic memory). The casing is manufactured in a non-circular MU "shape to fit within the existing pipe, then in its non-round shape introduced into the existing pipe and then expanded to a round state under heat and pressure against the existing pipe.

Published European Patent Application 0,000,576 proposes the introduction of a semi-rigid plastic pipe insert within an existing pipe. The semi-rigid plastic tube has sufficient hoop strength to withstand all or at least part of the external pressures that can be applied to it.

Most of the foregoing and other known methods using rigid or semi-rigid pipes for insertion into an existing underground pipe have a common drawback: because of their rigidity or near-rigidity, they must be straight or nearly straight, existing pipelines are introduced. This means, for example, with regard to underground sewer lines, that such methods are limited to use of main sewers because they usually have straight pipeline sections between manholes. Most, if not all known methods are not suitable for use in repairing the many house connections extending from the main sewers to buildings. Often such side pipes have bends or bends through which a rigid or semi-rigid plastic pipe cannot penetrate. Also, such side pipes are usually not accessible through manholes at both ends, and therefore known coating methods or installation methods for replacement pipes require manholes or other access forms at both ends to be excessively expensive. Most known underground replacement pipe installation methods require large excavations at one end of the side line to be re-coated or repaired to provide room for introduction of the straight rigid plastic replacement pipe. Such a large excavation adjacent to a building for which the side line serves, or at the other end where the side line arrives in the main sewer, is often impractical and usually expensive.

In addition, most known methods of recoating 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 pipe, which by definition crosses a main pipe at a point that is normally inaccessible through a manhole.

For the foregoing reasons, the known methods of recoating and repairing underground pipelines are simply not applicable to home connections.

Another drawback in using known methods for repairing and repacking existing pipeline sections crossed by house connections using straight rigid or semi-rigid pipes is that once the pipe is in place within the existing pipeline section it is very difficult to determine exact positions where they intersect piping main pipeline to cut access holes in the replacement pipe to allow access to the side piping. This is especially the case when the replacement tube is sufficiently thick and therefore has sufficient hoop strength to withstand characteristic hydraulic and ground pressures itself.

For the foregoing reasons, there is a need for improved methods, devices and equipment to allow for the repair of existing underlying pipeline sections, and in particular house connections and other pipeline sections with bends and curves, and pipeline sections that are not easily accessible are off both ends of the pipeline section to be repaired.

Accordingly, the main objectives of the invention are to provide the following: 1. A new and improved replacement pipeline product pre-installation in an existing underground pipe, which is particularly suitable for use in repairing and replacing existing house connections that are not straight and main lines crossed by house connections; 2. a new and improved method of manufacturing a pipeline product intended for repair and replacement, which is particularly suitable for installation in existing underground pipes that are not straight or that are crossed by side pipes; 3. a method of installing a new or replacement pipeline section in an existing underground pipe, and in particular in a pipe which is not straight or intersected by house connections; 4. an apparatus and tools for the manufacture of a pipeline article intended for substitution purposes as aforementioned j. A device and tools for installing a pipeline article as aforementioned in an existing underground pipe and in particular in a pipe which is not straight or which is crossed by side pipes; and 6. a device and tool for reforming a new or replacement thermoplastic pipe section installed in an existing underground pipe, and in particular a house connection, after the new or replacement pipe section is folded into a state, by reforming it to a stable round shape within the existing leadership.

The invention relates to a new and improved pipeline product, pre-repair and replacement, which is particularly suitable for installation in an existing underground pipe such as a house connection with bends and curves, and a range of closely related processes, equipment tools and tools for manufacturing the article, installing the article in an existing conduit, straight or curved, and reshaping the article into a round shape after it has been collapsed into the existing line. The article, method, devices and tools of the invention are particularly intended for use in installing the article in house connections and other existing subsurface pipes with access at only one end of the pipe or with bends or bends, or in pipes that are crossed by pipes.

According to one aspect of the invention, a pre-replaceable pipeline article is made of a thermoset plastic material such as PVC, initially extruded and formed into a unique folded and flat shape such that it retains a folded memory when reheated so that it is easily applied to a coil for storage and use, it has a reduced cross-sectional size for easy insertion into an existing underground pipe, that it can be fed through manholes, cleaning holes or other small vertical openings without sharp excavation or damage to the plastic material and around tight bends in deep pipelines, and that, despite its flat folded condition, a hot fluid can be passed therethrough for reheating along its entire length.

In accordance with another aspect of the invention, the aforementioned plastic pipe product is installed, for example, an existing curved side pipe, by reheating the plastic pipe to a flexible state, and then retracting the hot flexible folded plastic pipe into the existing side pipe with a pull cable and either a temporary site of the junction of the side conduit and the main conduit anchored pulley arrangement or with a cable leather from the nearest manhole in the main conduit. The folded installed pipe is then heated along its entire length by passing through it a hot fluid, plugging or restricting its front end, and injecting a fluid, such as air, underpressure into the other end to reshape and expand the pipe. to a round shape. While continuing to apply internal pressure to the reshaped round pipe, it becomes permissible cooling and thereby stabilizes its round shape.

In accordance with another aspect of the invention, various means are provided for plugging or restraining the front end of the plastic pipe to allow passage of a hot fluid therethrough in the folded state and allowing the folded pipe to expand and reform into a round shape. by applying an internal fluid pressure.

In accordance with another aspect of the invention, means are provided to cover or seal an inlet end of the folded pipe to allow internal fluid, depressurization into the folded pipe when introduced into an existing underground pipeline.

In accordance with another aspect of the invention, there is provided a unique pulley and cable device which can be pushed through a side conduit to its intersection with the main pipeline and temporarily anchored there by maintaining tension at both ends of the cable. One end of the cable is anchored to the front end of the folded pipeline to be installed; then the opposite end of the cable is pulled to pull the folded plastic pipe into an existing side conduit in a heated bendable condition.

In accordance with another aspect of the invention, various means are provided for heating the opposed ends and various other portions of the plastic pipe article to allow reworking of selected sections of the pipe for clamping, introduction of plugs, or for keeping the pipe sufficiently flexible over the entire length of the pipe for introduction into an existing pipe which is not straight.

The foregoing and other objects, features and advantages of the invention will become more apparent from the following detailed description, with reference to the accompanying drawings, in which: Figure 1 is a cross section of a conventional thermoplastic pipe, such as a PVC pipe used in accordance with the invention in its expanded round state; Figure 2 is a perspective view of the thermoplastic pipe of Figure 1 and of the pipe shrinking device from its round state to a collapsed, folded state for storage on a spool; Figure 3 is a cross-sectional view of the thermoplastic pipe of Figure 2 after it has been folded, taken along line III-III of Figure 2; Figure 4 is a schematic view showing a method of installing the folded and coil-stored thermoplastic pipe of Figures 2 and 3 from a manhole within a main sewer, with the folded thermoplastic pipe stored on a roll, and reheated pre-installation in the underground pipe to be repaired; Figure 5 is a schematic cross-sectional view showing a detail of the device for expanding the folded thermoplastic pipe of Figures 2 and 3 and rounding it after it has been introduced into the existing main pipeline shown in Figure 4; Figure 6 is a schematic sectional view showing an alternative construction for expanding and rounding the folded thermoplastic pipe after its introduction into an existing conduit; Figure 7 is a schematic sectional view of a typical house connection extending from a building to a main sewer, illustrating a method of installing the thermoplastic pipe in an existing house connection according to the invention; Figure 8 is a section through a preferred embodiment of the thermoplastic pipe of Figure 1 when folded for installation in an existing underground conduit; Figure 9 is a schematic side view of an apparatus for manufacturing the thermoplastic pipe of Figure 1 in a folded form as shown in Figure 8; Figure 10 is a vertical view of the gauge of the device of Figure 9 on an enlarged scale as used in the manufacture of the thermoplastic pipe in Figure 8; Figure 11 is a vertical view of a single calibration plate of the calibration device of Figure 10 as viewed from line XI-XI of Figure 10; Figure 12 is a plan view of a folded end portion of the thermoplastic pipe of Figure 8 with a fixed end clamping member for use in drawing the pipe into an existing pipe and for limiting the pipe end internal depression of the pipe for expansion. make possible; Figure 13 is a section on line XIII-XIII of Figure 12; Figure 14 is a somewhat schematic plan view of a cable and pulley device of the invention, also shown in Figure 7, for drawing the folded thermoplastic pipe of Figure 8 into a side conduit, the device shown in its operative position; Figure 15 is a view similar to Figure 14, but with the device of Figure 14 in a collapsed condition for insertion into a side conduit; Figure 16 is a somewhat schematic side view of the device of Figures 14 and 15; Figure 17 is a side view of a plugging tool used to plug an end of a length of the thermoplastic pipe shown in Figure 8 after the end has been rounded, for use in transferring fluid, heat and fluid pressure to it. interior of the thermoplastic pipe; Figure 18 is a vertical front view of the tool of Figure 17; Figure 19 is a view of an end of the thermoplastic pipe with the plugging tool of Figures 17 and 18 inserted into the pipe and clamped in place with a chain clamping member; Figure 20 is a view of the chain clamping member of Figure 19 for its application to the pipe and plug of Figure 19; Figure 21 is a cross-sectional view along line XXI-XXI of Figure 19, showing the chain clamping tool of Figure 19 and Figure 20 clamping the thermoplastic pipe end to the plugging tool of Figures 17-19; Figure 22 is a somewhat schematic longitudinal section through a front end portion of the thermoplastic pipe of Figure 8, with the end clamps of Figures 12 and 13 mounted on the pipe end and the rest of the pipe being expanded and rounded, and a cutting tool in accordance with the invention has been introduced into the rounding pipe end portion to separate the clamped end from the rest of the pipe? Figure 23 is a sectional view of the pipe and cutting tool of Figure 22 taken along line XXIII-XXIII of Figure 22; Figure 24 is a somewhat schematic side view of an end heater used to heat an end portion of the thermoplastic pipe to rework the end portion, with the heater shown installed on a folded end portion of the thermoplastic pipe of figure 8; Figure 25 is a perspective view of an inflatable end-capping tool used to plug or restrict the end portion of the thermoplastic pipe in place of the end clamp of Figures 12 and 13 to expand and round the folded thermoplastic pipe possible; Figure 26 is a shortened vertical view, partially in section, of the inflatable pipe of Figure 25; Figure 27 is a schematic view illustrating the installation of the inflatable plugging tool of Figures 25 and 26 in the thermoplastic pipe when expanded and rounded; Figure 28 is a schematic view similar to that of Figure 27, but showing the pipe of Figure 27 after it has been refolded with the inflatable plug inside it in a deflated state; Figure 29 is a schematic view illustrating the use of the inflatable plugging tool of Figures 25 and 26 during installation of the thermoplastic pipe in a side conduit; Figure 30 is a schematic view illustrating another application of the inflatable plugging tool of Figures 25 and 26; Figure 31 is a schematic view further illustrating the use of the inflatable plugging tool of Figures 25 and 26 according to the method illustrated in Figure 30; Figure 32 is a schematic view illustrating yet another use of the inflatable plugging tool of Figures 25 and 26 to expand and round the folded thermoplastic pipe after it has been inserted into an existing underground conduit; Figure 33 is a schematic view of a portion of a main pipeline and an intersecting side pipeline, illustrating an alternative method of drawing the thermoplastic pipe of Figure 8 into a repairable side line; Figure 34 is a schematic view of an end portion of the folded thermoplastic pipe of Figure 8 illustrating a method of detaching the pull cable from the front end of the pipe after it has been inserted into an underground conduit; Figure 35 is a schematic view similar to that of Figure 34 illustrating yet another method of detaching the traction cable from the thermoplastic pipe after it has been introduced into an existing underground conduit; Figure 36 is a section through the junction of a main pipeline and a side pipeline after the thermoplastic pipe of Figure 8 has been installed and expanded within the main pipeline to be repaired, using a method for determining and cutting an orifice through the newly installed thermoplastic pipe for restoring communication between the side pipe and main pipeline is illustrated; Figure 37 is a schematic side view illustrating a method and device for folding a thermoplastic pipe manufactured in a round manner for insertion into an existing underground conduit, Figures 38A-E are schematic cross-sectional views along lines XXXVIIIA-XXXVIIIA to XXXVIIIE-XXXVIIIE of Figure 37; Figure 39 is a somewhat schematic side view of a releasable end clamp with attached pull cable and release line, for use in clamping the front end of the folded pipe of Figure 8 during its installation; Figure 40 is a plan view of the end clamp of Figure 39; and Figure 41 is a plan view of the release wedge portion of the clamp of Figure 39.

In Figure 1, numeral 10 denotes a type of pipe used to renew, repair or replace underground pipeline sections such as sewer pipes or the like according to the present invention. A feature of the pipe is that it is formed from a thermoplastic material such as PVC and more particularly from a material which is usually rigid and thick-walled to have sufficient hoop strength to resist external ground and hydraulic pressures to which it may be exposed under the ground . Such a thermoplastic pipe can be made flexible when heated to temperatures of, for example, 105 * C (200 * F) or more, in the case of PVC pipe. A feature of the pipe 10 is that it is rigid in construction at typical above-ground and underground ambient temperatures but becomes flexible and processable to various shapes when heated or re-heated. Another feature of such thermoplastic material is that it has a memory, that is, if it is manufactured in a special shape such as a round tubular shape and then later heated and flattened or folded and then cooled to fold it shape and then reheated without hindrance, it will tend to return to its original round tubular shape. Conversely, if the pipe is initially manufactured in a collapsed and folded form, as shown, for example, in Figures 3 and 8, it will then be later heated and expanded under internal pressure to a round shape and then cooled and stabilized in the round shape. material tends to return to its original folded shape if it is subsequently reheated without hindrance. This memory aspect of the thermoplastic pipe is used to promote certain aspects of the present invention.

A common and readily available pipe of the type useful in the practice of the present invention is a polyvinyl chloride (PVC) pipe with standard size ratios (outer diameter / wall thickness) of the order of 13 to 65, currently available for underground pipelines such as drainage pipes, water pipes, etc. .

Although in the most preferred embodiment of the present invention, the thermoplastic pipe is manufactured in a folded form as shown in Figure 8 in the manner described with respect to the device of Figures 9-11, at least certain aspects of the invention can also be carried out using a thermoplastic pipe made in a tubular or round shape. Figure 2 illustrates an apparatus 11 for reshaping the conventional PVC pipe 10, which is made in a round shape. Figure 3 illustrates a cross-section of the pipe after it has been reformed by flattening and folding using the device of Figure 2. More specifically, the PVC pipe is heated in any conventional manner, such as heater 11a, which may be heated by a thermostatically controlled steam box or a house incorporating thermally controlled electric heating elements. By passing the original round pipe 10 through the heating box 11a, the pipe is heated to a temperature sufficient to make the pipe plastic or bendable. Then it is flattened or preferably folded in a folding device 11. reduce cross-sectional dimensions over all so that it can be easily pulled into an underground pipe with the same or slightly larger inner diameter as / than the original outer diameter of the thermoplastic pipe. The reduced folded size thermoplastic pipe is illustrated with 10a in Figure 3.

Although the unit 11 in Figure 2 schematically illustrates a pipe folding member, a practical pipe folding device and method are illustrated in more detail with respect to the device of Figures 37 and 38A-E. It will be seen that the round pipe 10, after passage through the heater 11a, is first flattened by a pair of opposed flattening rollers 60, 61 and then fed through below a folding wheel 62, meanwhile increasingly supported by three various sets of folding rollers 63, 64, 65. The pair of folding rollers 63 is mounted in conjunction with the folding wheel 62 to begin folding pipe 10 to a U shape. Thereafter, the three folding rollers 63 continue the folding process in that they are arranged in a semi-U shape for cooperation with folding wheel 62. Finally, the set of four folding rollers 65 is arranged in a U shape for cooperation with the folding wheel 62 about folding pipe. 10 to complete a U-shape. Thereafter, the folded pipe is passed through a containment mold 66 while cooling to stabilize the pipe in its U shape so that it has a U-shaped memory. From form66, the folded pipe can either be stored in predetermined length or passed through a steam tube to be reheated and made flexible for direct insertion into an existing pipe.

Alternatively, after the flattening process prior to folding, the pipe in its flat state can be applied to a coil in the hot box 18 shown in Figure 4, after which the flat coil-mounted pipe can be reheated at the site of work in the hot box, and then pulled out of the hot box and folded as previously described, just prior to insertion into the pipe to be renewed.

In some applications, it may be possible to install the thermoplastic pipe in a flat state in an existing pipe, especially if the thermoplastic pipe in its round state has a considerably smaller outer diameter than the inner diameter of the pipeline to be repaired. However, under most circumstances, it is preferred that the thermoplastic pipe be installed in a longitudinally folded form in an existing pipeline, as shown in Figure 3, Figure 8 or Figure 38E. Of all the folded shapes, however, the shape of Figure 8 is preferred for reasons explained below.

As previously mentioned, the thermoplastic pipe, when made in a round shape, has a memory that tends to return to its round shape when heated after folding. Thus, when it is necessary to heat the folded pipe to make it pliable for installation in an existing pipeline, the pipe will tend to revert to its round shape, perhaps prematurely, unless it resists. It is primarily for this reason that it is preferred that the thermoplastic pipe is initially manufactured in a desired folded shape. When the folded pipe is then reheated to make it pliable for insertion into an existing pipeline, the pipe will retain its folded shape until it is fully inserted into the existing pipeline and ready for reforming into a round shape.

Irrespective of whether the thermoplastic pipe is made in a round or folded shape, the pipe should be in a folded shape when ready for insertion into the existing pipe. It is also preferred that the thermoplastic pipe is wound up with heating and thereby flexible on a storage spool, such as spool 12 shown in Figure 4.

The folded thermoplastic pipe coil 12 is stored in a housing or "hot box" 18, which is equipped with a thermostatically controlled heater 24 for heating the interior of the hot box, and therefore the coil 12, around the folded pipe material 10, if desired. , flexible. Preferably, the hot box 18 is also equipped with an air circulation system 19 to prevent heat stratification within the hot box and thereby ensure that the folded pipe coil will be heated uniformly. The hot box 18 is preferably transportable and is shown mounted on the flat loading bottom of a truck 20 for transport to a work. A smaller shape of the hot box can be wheeled and moved by hand for use with small inaccessible pipelines such as house connections. In either case, either machine-operated or hand-operated means are provided for rotating the spool 12 for winding material on the spool or unwinding it from the spool. The hot box 18 is equipped with an access door 21 and may also be equipped with a down tube 22 and a roller 23 to facilitate insertion of the folded thermoplastic pipe into an underground pipeline through a vertical access opening such as the manhole 16 of the existing main sewer 14.

In the following, a method for repairing a main sewer will be discussed.

In accordance with one aspect of the invention, the hot box 18 is conveyed to an opening at work, such as the manhole 16, at a repairable underground pipe section such as the main sewer 14. The end of the reduced pipe 10a connected to a pull line 26, made available from an adjacent opening in the existing pipeline, such as another manhole (not shown), and connected by clamping members 28 with the free or front end of the new pipe. The new pipe has been made flexible by heating coil 12 in the hot box by means of heater 24. The pull line 26 is then, for example, operated by a winch at the location of the next manhole downstream manhole 16, around the flexible folded pipe 10a from coil 12. 22 and to pull tubular roll 23 in the existing pipe 14 to the next manhole. After introducing the folded new pipe, it is heated and expanded into a round or substantially round shape to provide a pipe that cures into a thick-walled, rigid shape with sufficient hoop strength to withstand external hydraulic and ground pressures.

Figure 5 illustrates one way of expanding the pipe with reduced diameters after it has been drawn into the original pipe to be renewed or replaced. According to this method, a pair of plugs 30 and 32 are inserted into the opposite ends of the folded pipe when at least the ends are in a heated flexible state. The plug 30 is installed at the rear end of the new pipe section, which is located at the inlet end of the existing pipeline. The plug 32 is installed at the front or drawline end of the new pipe after disconnection from the drawline. Each of the plugs 30 and 32 is equipped with circumferentially disposed expanding packing members 34, which are provided for releasable sealing engagement with the original pipe 14 and the new pipe 10a. Packing parts 34 are inflated through pressure lines 36, such as air pressure lines, leading to overhead controls (not shown). Plug 30 is provided with an inlet conduit 38 therethrough for insertion into the new pipe of an expanding medium such as fresh steam or hot water. Such a pipe is equipped with a suitable control valve 40 as well as a pressure gauge 42 and a relief valve 44. The plug 32 is provided with a discharge conduit 46, which communicates with the area between the two plugs and is suitably provided with a valve at 48.

The newly installed folded pipe, with plugs inserted at its opposite ends, is then internally heated by the small passages of fresh steam provided at the folds of the folds of the new pipe visible in Figure 8. Shut-off valve 48 at the downstream end is open, so that the entire length of the new pipe is heated. Shut-off valve 40 is then closed while pressurized steam continues to be introduced via plug 30 to pressurize the folded pipe, thereby reforming it and expanding into a round shape. If the new pipe is made folded, it must be cooled or allowed to cool after reaching its round shape while maintaining internal pressure, such as cool air pressure, so that the pipe becomes rigid in its round shape. This last step is not necessary if the pipe is manufactured in a round shape unless the pipe is expanded or stretched beyond its original diameter during reforming.

If no internal passages are provided in the folded new pipe, as would be the case if the pipe, as shown in Figure 3, is absolutely flat, then the new pipe should be externally heated, such as by passing fresh steam through the existing pipe, before plugs 30 and 32 are inserted into the ends of the new pipe. Then, with the new pipe heated over its entire length, plugs 30 and 32 could be easily inserted into its opposite ends, valve 48 would be closed, and fresh steam or hot water would be introduced through plug 30 to make the folded pipe turn it off and reshape it into a round shape.

Figure 6 shows another type of device for expanding the reduced pipe. Such a device includes a mandrel 50 with heating members 52 therein capable of heating the new pipe to a flexible condition. The mandrel 50 is connected to a pull cable 54 or other means for pulling it through the original pipe. heating the mandrel and applying tensile stress to the pull cable, the mandrel is pulled through the original pipe, expanding the new pipe to the desired diameter. Of course, with this method, the pull cable 54 would be introduced into the new pipe before the new pipe is folded for entry into the existing pipeline.

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

The following paragraph describes a method example.

In a specific pipe renewal process, conventional PVC pipe is obtained which has an outer diameter approximately one eighth of a decimeter (1/2 inch) smaller than the inner diameter of the pipe to be renewed. The PVC pipe has standard size ratios from wall thickness to outer diameter, as previously noted. The PVC pipe is heated to at least about 105-108 * C (200-210 "F) and reduced to the shape shown in Figures 3, 8 or 38e. The folded pipe is then stored in large coils so that it can be transported to During installation in an existing pipe or underground pipe, the new pipe is reheated, preferably in a hot box 18, to be made pliable and easily down substantially vertically through deep manholes then substantially horizontally through the existing pipe can be drawn Once installed in the existing pipe section, the folded pipe is plugged, heated and rounded. If desired, the pipe can also be expanded beyond its original or designed diameter in round form to fit close to the existing pipeline section .

In the lower section, the method for determining the home connection connection will now be discussed.

An advantage of expanding the newly installed thermoplastic pipe beyond its original design diameter is illustrated with reference to Fig. 36, where the existing pipeline section to be repaired is intersected by at least one house connection (drain from a building ) or other service side line. In Figure 36, the main pipeline 70 at the site of 72 is crossed by a service side line 74, such as a home connection. When the new thermoplastic pipe is installed in the main pipes is rounded and expanded or stretched beyond its original round design diameter to properly engage the inner wall of the existing main pipe 70, a bulge or pit 76 is formed at the location of the opening or crossing 72 of the service side line in the main line. This bulge 76 is in fact an indicator of the precise location of the service side line opening in the main line. By passing a television camera through the main line, the exact location of the bulge or the hole, and thus of the opening of the service side line, can be determined. Thereafter, a remotely operated cutting tool 78 can be moved along the main line to the exact location of the bulge and used to cut the bulge 76 out of the new pipe 80, again opening the access from the side line 74 to the main line. . Rounding and expanding or stretching of the newly installed thermoplastic pipe is accomplished by the previously described methods or by the methods described below with respect to additional embodiments.

The preferred form of the folded pipe will now be discussed in more detail below.

Although the flattened and folded thermoplastic pipes of Figures 3 and 38E are suitable for use in the described installation methods, the preferred form of such a folded pipe is shown in Figure 8. The thermoplastic pipe of Figure 8 is manufactured substantially in the folded form shown. This is generally a collapsed tube folded along a substantially curved spherical longitudinal fold 8i into a pair of overlapping legs, including a long leg 83 and a short leg 84. The long leg 83 terminates at a curved or spherical free end 85 to define a small longitudinal passage 86 through the folded pipe. The shorter leg 84 also terminates in a curved or spherical free end 87, which also defines a longitudinal passage 88 through the pipe. Furthermore, the gradually folded portion 82 defines a passage 89 along the interior of the fold from one end of the pipe to the other end.

The spherical fold and leg ends as described are important to prevent the folded portions of the pipe from tearing when folded, which may otherwise be the case if the pipe is folded in the manner shown in Figure 3, especially if the pipe is thick-walled. Passages 86, 88 and 89 are also important to allow steam or other hot fluid to pass through the folded pipe for its entire length for reheating and thus resume operation after the folded pipe is installed in a standing underground pipe. Without such access to the interior of the folds, reheating would be a long, slow process and very difficult to achieve.

The folded pipe shape of Figure 8 is particularly suitable for use as a replacement pipe in repairing house connections such as house connection 90, shown in Figure 7, leading from a junction 92 with a main pipeline 94 to a building 96 for which it serves is doing. Installation of a replacement pipe in such a home connection presents special difficulties due to the nature of such pipes. First, such side pipes present difficult access problems, they often run under lawns, trees and shrubs and are inaccessible through manholes. Excavation of existing side pipes that need to be repaired would therefore be very costly. When inserting a new side pipe into an existing underground side pipe, access is usually only practical from a single small vertical excavation adjacent to the building, as indicated by 98 in Figure 7. Such an excavation leaves little room for maneuvering or for a large amount of equipment.

Secondly, house connections are usually smaller in diameter than main pipes and often have sharp curves or bends, unlike main pipes that usually run straight from manhole to manhole. For example, the housing connection 90 has a bend at the site of 100, making it impossible to insert a straight stiff pipe into the existing side pipe. In Figure 7, the home connection line g90, accessible by the vertical excavation 98 adjacent extension 98, extends below a lawn 102 to the main line 94 at a significant depth below a street 104. The methods and devices to be described are particularly suitable for solving the unique problems of installing a replacement side pipe into an existing underground side pipe from a single small, generally vertical access opening. Such methods and devices utilize the manufactured form of folded thermoplastic pipe shown in Figure 8.

In the following, a method and apparatus for manufacturing thermoplastic pipe in folded form will now be discussed.

Figures 9, 10 and 11 show that the folded thermoplastic pipe of Figure 8 is manufactured using a conventional plastic pipe extruder 106 which extrudes to a suppression box 108. A puller 110, a series of opposed pinch rollers 111,112 downstream of the vacuum box draws under tension the extruded and molded material from the vacuum box and passes it through a rewarming steam tube 114 to a flexible state so that the resulting folded pipe can be wound in its folded form on a storage coil 116, which would typically be located in the hot box 18 of Figure 4.

A mold 118 and a pin 120 are located at the outlet of the extruder. Between the downstream end of mold 118 and the inlet to the vacuum cabinet 108, there is a spacing 121 of about 3 to 6 decimeters (12-14 inches).

The vacuum cabinet is divided internally by partitions 122, 123 into three sections. All three sections are filled with water to a level 124 within the cabinet. The first or upstream portion of the cabinet is connected to a negative pressure source 125. Although the entire negative pressure cabinet is under negative pressure due to such connection, a maximum negative pressure is present in the upstream portion of the cabinet. A calibrator 126 is provided in the first section of the vacuum cabinet. The calibrator forms and maintains the extruded plastic material in its desired folded shape as the material is cooled and thereby hardens. The water inside the vacuum box has a cooling function, and the vacuum applied to the cabinet cooperates with the calibrator to keep the plastic material in its desired folded shape until cooling is able to maintain such a shape Under coercion.

In Figures 10 and 11, it can be seen that the caliper includes a series of calibration plates 128 spaced apart and joined by joining rods 130 and spaced by spacers 132 between plates on the rods. The rods are threaded at their opposite ends and secured by nuts 134. The calibration plates 128 located closer to the inlet end of the calibrator are placed closer together than those further downstream, due to the greater plasticity and fluidity of the plastic at the inlet end portion and therefore, due to the greater need to maintain the shape of the extruded material in that portion of the calibrator. Optionally, the jig also includes a central tube 136 with openings 137 for transferring cooling water to and between the plates for rapid cooling of the plastic material.

Figure 11 shows that each. calibration plate 128 includes a precision cut opening 138 with the exact circumference and outer dimensions of the folded pipe formed and maintained in the calibration plates. Each plate 128 of the potash brewer has exactly the same opening size and shape. By comparison of Figures 8 and 11, it will be noted that the opening 138 of the calibration plate includes a short leg 138a corresponding to the short leg 84 of the folded pipe. and a long leg 138b corresponding to the long leg 83 of the pipe, as well as a round folded portion 138c corresponding to the round longitudinal fold 82 of the pipe.

In the manufacture of the pipe of Figure 8, untreated plastic blend such as polyvinyl chloride is fed through an input hopper 107 into extruder 106, where the material is heated to a temperature of, for example, approximately 205 ° C (360 * F) and then through the mold 118 extruded where the very hot plastic material meets pin 120. The shape and the pin are sized to mold the plastic to the desired final size and shape of the desired tube. The plastic material is passed over gap 121 to the first portion of the vacuum box 108 and through the calibration plates. The plates shape and hold the plastic material in the shape and dimensions determined by the openings 138 of the calibration plates.

When the plastic material first enters the calibration device, it is very hot and quite liquid, and thus the calibration plates 128 are placed very tightly at this point to maintain the desired shape. The vacuum within the cabinet holds the plastic against the outer circumference of the opening 138 as the cooling water cools the plastic material. If desired, compressed air can be passed from a source 140 in pin 120 through the internal passages 86, 88, 89 of the folded plastic molding to ensure that the plastic does not collapse completely and to maintain the tubular shape of the folded pipe. Once the plastic material reaches the downstream end of calibrator 126, it is substantially cooled and capable of retaining its proper shape under tension generated by pull rollers 110.

Such rollers pull the folded plastic out of the vacuum cabinet in a continuous strip. From the calibration plates, the strip moves through the second and third chambers of the vacuum cabinet, where it hardens increasingly. When the strip 10 exits a one-time vacuum cabinet, the strip is cool and rigid, and has essentially the shape shown in Figure 8. By pulling the strip or stream of material out of the extruder under tension, the puller 110 controls the wall thickness and other dimension parameters of the folded pipe.

From the puller 110, the folded strip of steam tube 114 is passed, into which, through an inlet opening 117, a steam source 115 is passed to reheat the strip into a flexible state so that it can be reeled up on a storage spool 116.

The number and spacing of the calibration plates used in the calibrator is a function of the extrusion rate as determined by the pulling means of the desired wall thickness of the finished pipe.

As previously mentioned, the coil 116 of stored folded pipe 10 can be installed in the hot box 18 shown in Figure 4 for transport to and use on site.

The following will now discuss a method, apparatus and tools for installing a thermoplastic pipe in a side pipe.

Figure 7 illustrates not only a sewer side pipe as previously described, but also a method, device and tool for inserting the folded thermoplastic pipe of Figure 8 into the side pipe. First, a vertical excavation98 must be dug, preferably as close as possible to the building96 the side line 96 serves for, to break through and provide access to the existing side line 90.

The length of the side pipe to be repaired or replaced can be determined by inserting a flexible fiberglass rod into the side pipe at the excavation site and passing the rod through the side pipe until it crosses main line 94. When this occurs, the length of the rod within the side conduit may be marked at the access opening and the rod may then be withdrawn and measured to determine the length of plastic pipe 10 required for the job. When the lengths of a series of side lines to be repaired are known, the folded pipe 10 can be pre-cut to match such lengths, either at the manufacturing plant or at another remote location. After that, such pre-cut lengths can be transported to the works for installation.

Alternatively, the required length at the location of the work may be cut from the spool 116 or 12 (Figure 4) within the work case transported to the work. If the excavations for the side pipes to be repaired are not accessible to the truck 20 on which the hot box 18 is fitted, the necessary length of plastic pipe 10 can be stored on other smaller coils with smaller wheels mounted on it. Heated cabinets (not shown), which are driven to the respective excavations. A smaller "mini hot box" 140 is shown in Figure 7 and encloses a coil 142 of folded pipe 10.

Alternatively, instead of pre-measuring and pre-cutting the desired lengths of folded plastic pipe 10 to lengths corresponding to the lengths of the side pipes to be repaired, the folded pipe 10 can be heated only inside the hot cabinet 140 and in the existing side conduit until the new folded pipe reaches the junction with main conduit 94 and is then cut at the coil.

If the folded plastic pipe 10 is pre-cut to length at the factory, it can also be transported in its pre-cut lengths to the various works and heated there for introduction into the existing side pipe in a steam pipe, such as the steam pipe shown in Figure 9. 114. The steam tube can be made of cloth or metal or equivalent materials, with flexible fiber ends or equivalent ends that can be tied around the folded plastic pipe to keep the steam within the steam tube. Such pipes are lightweight for easy transportation to work and can be 6 meters (20 feet) or longer. For use in the field, a fabric steam tube is preferable to a metal tube due to weight considerations.

If the sewer side pipe is straight and the access opening at the excavation site is close enough to the surface, or if the excavation is large enough, it may be possible to insert the necessary length of folded plastic pipe 10 into the existing side pipe. by simply pushing the new pipe into the existing pipe until the front end reaches the main line. Often, however, this will not be possible due to the need for the new pipe to pass a bend at the excavation site or somewhere along the side pipe, or both. In such cases, it is necessary to heat the usually rigid folded plastic pipe to make it longitudinally flexible to pass the bends and to pull the new folded pipe into the side, rather than pushing it. Pulling the flexible folded plastic pipe into the existing side conduit without an opening at the end of the side conduit located on the main conduit presents special problems solved by the present invention.

The following will now discuss how to retract the new side pipe into the existing side pipe from the access opening.

A method of inserting the new side conduit into the existing side conduit by pulling involves the use of a pull cable attached to the front end of the new side conduit. The cable passes around a pulley at the junction of the side conduit with the main conduits and then returns to the entrance to the side conduit. By applying a pulling force to the pulling rope from the access opening at the excavation 98, the new pipe can be pulled through the entire length of the existing side conduit. This method involves the use of special tools.

First, the front end of the new side pipe must be clamped tight to limit the size of the passages 86, 88, 89, as shown in Figure 8, to allow internal suppression of the folded pipe after it is inserted into the existing side pipe, still allowing passage of hot fluid through the folded pipe so that it can be heated along its entire length and thereby kept flexible for expansion and rounding. To achieve this limitation and end clamping, an end clamping member, as shown in Figures 12 and 13, is used. A side view of the end clamp is also shown in Figure 22. In these three figures, end clamp member 144 includes a pair of rigid metal plates. The plates comprise a top plate 145 and an opposing bottom plate 146. Both plates have forwardly projecting nose portions 147 with extending, aligned cable tie holes 148 therethrough. Another pair of aligned holes 149 extends behind the cable hole 148 through the bottom plate and the top plate to receive a clamp bolt 150. The bolt 150 also extends through aligned holes 151 through the folded artifacts. fabric pipe 10.

For example, before installing the end clamp 144 on the front end of the folded plastic pipe 10, the front end of the pipe is heated in a final heater 152 shown in Figure 24 to make it flexible. Final heater 152 includes a thin-walled rigid pipe 154, which is closed at one end by an end plate 156 to a central inlet port 157 with a steam hose connection 158. The opposite end of the heater includes a flexible wrap 160 of cloth or other suitable fabric, at the location of connecting tape 162 to the pipe 154. The free end of the cover 160 can be tightened or tied around the folded plastic pipe 10 such that steam can escape at the connection 164 of the cover with the pipe, so that the the entire end section of the pipe is heated to the desired temperature upon injection of steam into the pipe interconnect 158. The length of pipe 152 may be approximately 6 decimetres (2 feet) for most purposes, although depending on the application can be longer or shorter.

After the front end of the pipe 10 has been made flexible, the plates of the end clamp 144 are mounted on the end of the pipe and the bolt 150 is passed through the bolt holes 151 and tightened so that the opposing plates 145, 156 are an intermediate portion of the folded pipe to a flatten to reduce the size of the passages 86, 87, 89 at the end of the folded pipe. It should be noted that the widths of the clamping plates 145, 146 are substantially smaller than the overall width of the folded pipe 10, so that the passages 89 at the fold and 86 at the end of the long leg are not entirely become closed when clamping force is applied to the folded pipe. Therefore, when the clamp is applied, fluid can still pass entirely through the clamped end of the pipe, but the passages are small enough that an internal pressure build-up within the folded pipe can be achieved to expand and round the pipe.

The final heater described is also useful for other purposes, as will be readily apparent from the following description.

The following will now be discussed in more detail on a detachable end clamp.

Another form of end clamp, which can be used in place of the end clamp 144, is a detachable end clamp 250, shown in Figures 39-41. Clamp 144 has the disadvantage that it cannot be removed from the front end of the pipe 10 when inserted into a dead end pipe without cutting the clamped end of the pipe using a special remote-controlled cutting tool as shown in Figures 22. and 23 and described below. However, the releasable end clamp 250 can be remotely detached from the sprouted end of the new pipe if desired and pulled with a cable from the existing conduit.

The releasable clamp 250 includes an upper jaw 252, which is rotatably mounted on a lower jaw 256. Lower jaw 256 includes a front end protrusion 258 having a pull cable hole 260 extending therethrough for mounting a pull cable 262. The jaws 252, 256 are provided with gripping ends 263, 264 for gripping and compressing, when hot and flexible, a front end portion 266 of the folded plastic pipe 10.

A bolt 268 extends through a large opening 270 larger than the head 269 of the bolt, and through an aligned smaller bolt hole 272 in lower jaw 256. The bolt hole 272 is smaller than the nut 273 and the bolt head 269. 268. A fork-shaped release wedge member 276 includes parallel arms 277, 278 that define a slot 280 and are joined to a vertical wedge-shaped body 282. A flexible release cable or cord 284 is secured to the body 282 by passing through body hole 286. wedge member 276. is designed to be bent between the head 269 of bolt 268 and the top surface of upper jaw 252, the arms 277, 278 extending below the head and slot 280 receiving the shaft from the bolt. Thus, the bolt head 269 is pulled against arms 277, 278 rather than through the large upper jaw opening 270 when the assembly is secured to clamp the jaw ends 263, 264 against pipe 10.

To loosen the clamp from the new pipe after the pipe has been retracted into the existing sewer side pipe using pull cable 262 and after the new pipe has been rounded except for the clamped end, the release cable 284 is pulled. 250 pulled away from under bolt head 269 (or nut 273, if the nut end of the bolt is above the maxilla), allowing the bolt head to fall through the large opening 270 into the maxilla 256 and the jaws to open to teach the pipe end. The wedge member and clamp can be pulled out of the side conduit or the main conduit using their respective pull cables.

The following will now discuss in more detail a pulley and cable cleat.

Another tool used to retract the new folded side conduit into the existing side conduit from the access opening 98 is formed by a pulley and cable member, referred to as a "frog", as shown in figures 14-16. The frog 152 includes a cable pulley wheel 154, which is rotatably mounted within a pulley housing 156 on a shaft 157. A pair of angular legs 158 are mounted opposite sides of the open rear end of the pulley housing. Each leg includes a front leg portion 158a and an integral with it hind leg section 158b. A pair of flexible steel leg guide bands 160, which are curled inwardly at their rear ends 161, extend backwardly from the rear leg portions 158b. The pivot joints 162 of the legs 158 with the housing 156 are spring loaded to force the legs outward as shown in Figure 14. However, the legs can be rotated inwardly to the positions shown in Figure 15 to allow the legs and therefore the entire assembly to move through the side conduit.

A pair of substantially triangular arms 164 are rotatably mounted at the meeting points of the front leg portions 158a and the rear leg portions 158b at the location of spring loaded pivot joints 166. The spring loaded connectors 166 force the arms 164 to their expanded positions shown in Figure 14, perpendicular to the rear leg portions. 158b, when in their expanded positions of Figure 14. However, the arms 164 can be collapsed against the spring pressure to their collapsed positions, shown in Figure 15, again to allow the frog to move through its side line to its destination. A pull cable 168, both ends of which lead back to the access opening 98, is passed around pulley wheel 154.

With its pull cable 168 attached, but with both ends of the cable leading back to access opening 98, the frog is inserted into the existing side conduit and pushed through it using a flexible fiberglass push rod (not shown). When the frog reaches the junction of the side line with the main line, and the housing 156 and the associated pulley are pushed into the main line, and the front legs 158a have also entered the main line, the arms 164 spring outward from their positions shown in Figure 15. their open positions shown in Figure 14. In the open position of the legs, the rear leg portion 158b and their associated leg straps 160 press against the inner wall of the existing side conduit. At this time, both ends of the pull cable 168 are pulled to firmly anchor the frog at the junction of the side and main lines.

While continuously applying tension to the pull cable to keep the frog anchored in place, one end of the pull cable is attached to end clamp 144 (Figures 12 and 13) or detachable end clamp 250 (Figures 39-41). The other end of the cable, still at the location of access opening 98, is pulled, pulling the heated, flexible, folded plastic pipe 10 through the side pipe and around bend 100 until the front end of the folded pipe crosses the side pipes to the main pipe reached at the location of frog 152. Tensile force to achieve this may be applied to cable 168 either by hand or by using a hand or machine operated winch 170 (Figure 7) at access opening 98. Due to the triangular shape of the arms 164 appearing on the cable 168 applied tensile force that causes the frog to jerk up or down.

After the new folded plastic pipe reaches the frog in the main pipe, the cable connection to the pipe end clamp is loosened and a cable end is pulled through the pulley, causing the frog to fall into the main pipe. The cable is pulled from the service line from the entry opening and the frog can be retrieved from the main line at a later stage using conventional retrieval methods. At this time, the folded plastic pipe 10 is fully inserted into the side pipe to be repaired, with its clamped front end in place of the main pipe. The folded plastic pipe is now ready to be reheated and expanded into a round shape in the existing service side pipe.

Before discussing the expansion and rounding, as used in service side lines, mention should be made of the methods and means for detaching the puller 168 from the end clamp 144 so that the cable can be pulled through the frog. This can be accomplished in various ways, as shown, for example, in Figures 34 and 35.

Figure 34 illustrates what is referred to as a breakaway cable release arrangement. In this method, a "slack" end 168a of the pull cable 168 is attached to a breakable cord or cable 172 of relatively low strength, which in turn is taped at the location of 173 to the front portion of the folded pipe 10 to be inserted into the existing side leadership. From this slack end, the pull cable 168 is loosely passed through cable hole 148 in the end clamp, as indicated by slack loops 168b, 168c, and then passed through the frog's pulley. The tensile end of the cable remains at the location of the side pipe access opening. If no end clamp is used, the cable hole 148 can be drilled directly through the folded front end of the plastic pipe. When the winch at the access opening pulls the cable through the cleat to pull the folded new pipe into the existing side conduit, the cord 172 maintains moderate tension on the slack end of the cable. When the front end of the new folded pipe reaches the cleat, the pull end of the cable is suddenly pulled, breaking the cord 172 and releasing the slack end 168a of the cable through cable hole 148 so that the cable can be retrieved.

Figure 35 illustrates a similar cable release method, which is referred to as the manual cable release. In this method, the slack end portion of cable 168 is again slapped twice through the cable hole 148 at the front end of the new folded pipe 10 to form double loops 168b, 168c. The pull cable 168 is then fed through the existing side conduit 90 to the frog and back to the entrance opening. The slack portion 168a of the cable must be longer than the length of the new pipe to be introduced 10. When the winch pulls the new pipe into the existing side pipe, a moderate tension is maintained at the slack end 168a of the cable, causing the new folded pipe to the side line can be drawn. When the new pipe is properly inserted into the existing side conduit, the slack end 168 of the cable is released at the entry hole, allowing the cable opening 148 to be released from the front end of the newly inserted pipe.

The method and the device for expanding and rounding the folded pipe within the side pipe will now be discussed in more detail below.

With the folded new pipe in place within the existing side pipe, it is ready to be expanded and rounded to replace the existing side pipe as a duty side pipe. At this time, the front end of the new folded pipe 10 is already limited by an end clamp 144 or 250, so that the folded pipe can be pressurized internally by fluid and yet allow hot steam or other fluid to pass through it. This allows heating the entire internal length of the folded pipe to a flexible state for expansion. Of course, at this time, the rear end of the newly introduced folded pipe is also capped to allow introduction of hot steam or other fluid into the pipe for heating and expansion, such a cap member or plug is shown in Figures 17-21.

A generally conical plug, referred to as a "torpedo plug" 176, includes a substantially conical front portion 178 with an opening 180 at its front end. Conical portion 178 extends backwardly to a short cylindrical portion 182 covered by a rear end plate 184, Plate 184 includes an inlet port 186 and a hose connection 188 for coupling a steam or hot water supply hose so that hot fluids can be introduced under pressure into the interior of the folded pipe. Other hose connections may be provided through end plate 184, such as an air hose connection, for expanding the pipe using air pressure or for maintaining air pressure in the expanded pipe during curing in the expanded, round state.

While heating the rear end of the folded pipe 10, such as by using the previously described final heater 152 to make it flexible, the conical portion of torpedo plug 176 is driven into the rear end of pipe 10 as shown in Figure 19 until end cover 184 touches the end edge of the new pipe, thus expanding the end of the new pipe into a round shape corresponding to the outer diameter of cylindrical plug portion 182. An adjustable chain clamp 190 is used to tighten the expanded end portion of the new pipe. clamp the cylindrical portion 182 of the torpedo plug to seal the pipe to the plug.

Details of the chain clamp 190 are shown in Figures 20 and 21. The chain clamp includes a clamping plate 192 with a curved, pipe-engaging surface 193. On the convexly curved outer surface of the plate, a tension iron (device) 194 is provided, between which a nut part 195 rotatably mounted. Nut portion 195 receives a threaded rod 196 with a rotatable end 197. A clamping 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 anchor column 199 on the outer surface of clamping plate 192.

With the end of pipe 10 heated and flexible and the torpedo plug 176 inserted into such an end, the clamping plate 192 is placed on the rounded pipe end and the chain 198 is wrapped around the cylindrical pipe end, tightened by hand as tightly as possible and then anchored to anchor column 199. Clamping pressure is then applied by rotating the threaded rod 196 in one direction to shorten the effective length of clamping chain 198 using a wrench tool mounted on the rotatable end 197 of the rod. It is important that the clamp is easily tightened. because the plastic pipe tends to deform under heating, and the clamp must be tightened in place while heating and rounding 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 connector 188. Hot steam is forced through the length of the folded pipe, more particularly through the narrow passages through it, allowing the complete Length of the pipe is heated. At the same time, the restriction effected by the end clamp at the front end of the folded pipe allows the pipe to be internally depressurized to about 170 kPa (25 psi). When the pipe becomes heated and pressurized, it expands and develops to its cylindrical shape along its length, except at the location of its clamped end portion.

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

The following will further elaborate on the removal of the clamped end of the new pipe.

The next step is to remove the end clamps the still folded and clamped front end portion of the new pipe from the remaining rounded portion of such a pipe, this is accomplished by cutting the clamped and folded front end from the expanded and rounded new pipe as shown in figures 22 and 23.

Figures 22 and 23 show a separator for cutting the folded and clamped front end of the expanded and rounded pipe 10 into the existing pipe. The separator includes a machine-operated cutting tool 200. The cutting tool comprises a small high-speed electrical or pneumatic motor 202, which is contained within a single-cylinder motor housing 204 with a significantly smaller diameter than the inner diameter of the rounded plastic pipe 10. A flexible air hose or an electric power cord 206 supplies power to the motor 202 from a remote source at the entrance opening of the existing service side guide. A rotor 210 is mounted on a motor drive shaft 208, to which a pair of cutting or swinging blades 212, 213 are rotatably mounted at rotary joints 214 adjacent to the outer ends of the rotor.

Motor housing 204 is encased in an inflatable rubber sleeve 216 which, in expanded form, centers the cutting unit in place and anchors it within the rounded plastic pipe. A flexible air supply hose 218 supplies pressurized air to inflate sleeve 216.

Although the shown baffles 212, 213 are steel, they may also be made of chain or cable and are designed to extend outwardly under centrifugal forces as the rotor 210 rotates, to punch and cut the plastic pipe 10 .

In use, the cutting unit 200 is pushed through the new plastic pipe 10 after the pipe is installed and rounded. Pushing can be accomplished using a flexible fiberglass rod and rubber sleeve 216 in deflated form. The cutter is pushed into the existing side pipe until it reaches the collapsed and clamped front end. At this time, sleeve 216 is inflated to anchor and center the cutting unit within the rounded plastic pipe. When the sleeve is inflated, the motor 202 is energized by supplying energy thereto via air hose or electrical cord 206. The motor rotates the rotor 210 to actuate swing blades 212, 213 until the blades cut off the clamped and folded end of the plastic pipe. The separated end falls into the main pipes can later be retrieved in the usual manner.

After the front end of the pipe has been cut, the sleeve 216 is deflated again and the cutting unit is retrieved from the rounded plastic tube by simply pulling the air hose 218 and the power cord 206 from the entry end of the new pipe. pipe is now installed in the existing side pipe, and after it is connected to the portion of the side pipe leading to building 96 (Figure 7) it is ready for use.

The following will now discuss alternative methods and devices for installing and expanding the new pipe in an existing side pipe.

Figure 33 illustrates an alternative method for pulling a folded plastic pipe 10 through an access opening 98a into an existing side conduit 90a which crosses a main pipeline 94a at a junction 92a. At some distance from intersection 92a, main line 94a is provided with a manhole 216 for access to the main line. A cable winch 218 is placed at manhole 216. The front end of a pull cable 220 is inserted at the access opening 98a into the existing side conduit 90a and pushed through the side conduit to junction 92a by a flexible fiberglass rod, the front end of which Is equipped with a gripper for gripping the front end of the pull cord 1.

The front end of the push rod is also curved, so that when it reaches the junction, it can be guided around the acute angle to the main pipe. At that point, the pushrod advances to push the pull cable 22 through the main line, as shown at 220a, until the front end of the pull cable reaches the manhole 216. The front end of the pull wire is attached to the winch wire on site. The rear end of the pull cable 220, which is still in the access opening 98a to the side conduit 90a, is connected to the front end of the folded pipe 10, using one of the previously described cable release methods. The new pipe, after being heated in hot cabinet 18 for bending it, for example, is drawn into the existing conduit 90 by winch cable 220 using the winch 218 at the manhole 216. Pulling is continued until the front end of the pipe. the new pipe reaches intersection 92a. Then the pull cable 220 is released from the front end of the new pipe, using one of the previously described techniques. The new pipe is now ready for expansion and rounding within the existing side line 90a using either the rounding method described previously or another method to be described.

A method of rounding the pipe using an inflatable plug will now be discussed in more detail below.

Another method and apparatus for expanding the newly installed plastic pipe within an existing service side line is shown in Figures 25-29. This method is known as the inflatable plug method. The inflatable plug 222 used in this method is shown in Figures 25 and 26. This plug is used in place of the end clamp 144 (Figures 12-13) or the end clamp 250 (Figures 39-41) to seal or limit the inaccessible front end of the new plastic pipe, so that such a pipe can be pressurized, rounded and expanded. The plug is designed to be able to hold at least 170kPa (25 psi) air pressure, expand to an outside diameter with the inside diameter dimension of the rounded new pipe, but not burst if not restrained by the new pipe. The plug should also be designed to withstand temperatures in excess of 105 * C (200 * F).

The inflatable plug could be constructed from a single layer of flexible material if a suitable material could be found to meet the foregoing specifications. However, such a suitable material has not yet been found. As a result, a two-layer construction of the plug is now used. The plug is composed of an outer tube 224 of cloth or other fabric, which is folded, closed and stitched at its front end 225. The outer tube 224 has a diameter expanded state corresponding to the desired inner diameter of the new pipe when it is rounded. The rear end 226 of the fabricated tube remains open. An expandable rubber inner tube or bladder 228 is placed within the fabricated tube. The total length of the plug can vary from about 3 to 60 decimeters (1 to 20 feet), depending on the application. The rear ends of the fabric-made outer tube and the inner rubber tube are gathered around a pipe stem 230, which provides an air hose connection 232 for an air or steam supply hose 240 for supplying pressurized fluid to the interior of the inner tube. The rear ends of the outer inner tube are gathered around pipe stem 230 and tightly tied together by a band clamp 236 to prevent leakage of pressurized fluid from the inner tube.

The inflatable plug as described is typically used in installing and rounding new service side lines so that the previously described end clamps and end cutters need not be used. A typical method of using the inflatable plug is as follows:

The required length of folded plastic pipe for a particular existing service side pipe is heated and rounded in the workshop using, for example, the steam pipe described previously. The plug pressurizing hose 234 is inserted through the length of the rounded plastic pipe with the inflatable plug attached thereto until the plug is positioned at the front end portion of the rounded plastic pipe.

At this time, the pre-cut length of rounded plastic pipe is reheated and refolded with the deflated plug and connected air tubing folded in for field use. Figure 27 shows the insertion of the air hose and connected deflated plug 222 into the rounded plastic pipe 10. Figure 28 illustrates the refolding of the pipe 10 with the deflated plug 222 and hose 234 within the folded pipe.

At the location of the work, the plastic pipe is heated and folded and introduced flexibly into the side pipe to be renewed. When the folded plastic pipe has been fully inserted, it is heated by passing steam through the pipe, the plug being still empty. When the full length of the installed plastic pipe is heated, the plug is inflated via air hose 234 to expand the plug and thus the still hot, flexible front end portion of the plastic pipe surrounding the plug to completely seal the front end portion of the plastic pipe . After the plug is inflated, the plastic pipe upstream of the plug is pressurized by, for example, compressed air, rounded and expanded, the air being supplied through a hose 236 leading to the torpedo plug 176 at the rear of the new one. pipe at the location of the access opening 98.

After the new plastic pipe has been fully expanded to a desired diameter within the existing side conduit 90 and the pipe is then allowed to cool, the plug 222 is again deflated and withdrawn from the newly rounded pipe 10 by means of its air hose 234. The newly installed plastic side pipe is now ready for use.

In the following, further methods of using the inflatable plug will now be discussed.

Figures 30-32 illustrate some method of using the inflatable plug just described.

A slight variation from the method illustrated in Figures 27-29, the use of the inflatable plugs constitutes a sliding plug during rounding of the pipe. According to this variation, referring to Figure 30, the inflatable plug 222 and its air hose are installed in the pre-rounded plastic pipe 10 and folded with the pipe as before, but the plug is about 15 cm or so slightly from the front end 238 of the pipe, so that the front end can be folded as compact as possible for ease of insertion into the existing side pipe. The folded pipe 10, with the deflated plug 222 inside, is installed in the existing side pipe as previously folded. The rear end of the new pipe is plugged by means of a torpedo plug 176, with air hose 234 extending through a seal in the torpedo plug.

With the inflatable plug 222 deflated, the folded pipe is steam heated internally along its length to make it flexible. Air hose 234 is pulled taut from the torpedo plug 176 where it protrudes and a clamp 240 is placed 30 cm or so slightly behind the rear end of the torpedo plug. When the folded new pipe is hot, the inflatable plug is inflated. In addition, the folded new pipe between the inflated plug 222 and the torpedo plug 176 is pressurized with compressed air injected through air line 236 through the torpedo plug. The negative pressure application of the new pipe forces the inflated plug 222 to slide to the front end 238 of the new pipe until it is stopped by the contact of clamp 240 against the rear end of the torpedo plug. At this point, the front end, like the rest of the newly installed pipe, will be fully rounded. The inflated plug 220 is now deflated and the inflated plug is withdrawn from the newly installed pipe.

Figure 32 illustrates another method of using the inflatable plug 222 to plug, round and expand the new pipe within an existing side pipe or other pipe with access from only one end.

According to this method, the new pipe is inserted into the side conduit in a folded condition, using one of the previously described insertion techniques and without the front end clamp or the inflatable plug to seal or restrict the upstream or downstream end thereof. However, at least about 3 meters extra length of the folded plastic pipe is left uncovered at the location of the access end to the existing side pipe. The folded pipe is heated internally with steam to make it flexible over its length. When hot, an external clamp 242 is applied to the folded pipe about 3 meters (10 feet) downstream of the torpedo plug 176. Then the top 3 meters (10 feet) or so of the plastic pipe between the clamps round the torpedo plug by injecting steam from line 236 through the torpedo plug into the top 3 meters (10 feet) of the folded pipe. The rounded 3 meter (10 feet) pipe is allowed to cool in its rounded state.

The torpedo plug 176 is now removed and the inflatable plug 222 is introduced in at least a partially inflated state for ease of insertion into the rounded portion of the new pipe. Torpedo plug 176 is reinserted into the end of the rounded portion of the new pipe with the air hose 234 from the inflatable plug extending therethrough. Now clamp 242 is removed from the new pipe and deflates the inflatable plug 222. The new pipe is again internally heated with steam along its length to make it flexible again. When the new pipe is hot, the inflatable plug 220 is partially inflated. The internal pressure within the new pipe, which may be steam or air pressure, is increased and the partially inflated plug 222 is propelled through the new pipe, which is currently partially unfolded and partially rounded. When the inflatable plug 222 reaches the downstream or front end of the new pipe, this plug is fully inflated to plug the end closed. The new pipe is now pressurized with fluid, fully rounded, and thus cooled stabilized in its rounded state. When a new pipe is cured, the inflated plug 222 is drained and withdrawn from the fully rounded pipe.

The sealing of the pipe at the remote end will now be discussed in more detail below.

A method and means are provided for sealing the space between the new rounded pipe and the existing pipe, where such pipes intersect another opening, either a manhole or another pipe. A typical pipe junction could be found in the downstream end of a home connection where it flows into a main sewer.

The seal simply consists of a compressible rubber sleeve, which surrounds the intersecting end of the folded new pipe. It is typically about 0.3 to 0.6 cm (1/8 - 1/4 inch) thick, but can be of any reasonable thickness. The sleeve is typically 3 to 6 decimeters (12 to 24 inches) long, but can be any length.

When the front end of the folded new pipe is installed and accessible, such as at the location of a sleeve hole, the sleeve can be slipped over the folded end of the new pipe before that end is rounded. Then the sleeve, during rounding of the pipe end, is also rounded. The new pipe is expanded during rounding until the rubber sleeve is firmly compressed between the new pipe and the existing pipe to form a fluid tight seal. A different method is used to seal the remote and inaccessible downstream ends of house connections. A rubber sleeve with an adhesive on the back is used. The front end of the folded new pipe is heated, unfolded and rounded for insertion into the existing pipe. The sleeve with. the adhesive back is applied to the rounded end, and the end is refolded with the sleeve attached. Then, the folded new pipe is fed into the existing pipe, using one of the previously described methods.

Use of the previously described expandable plug forms the preferred method of rounding and expanding the remote end to be sealed. With such a plug, the expansion and thus the seal is more complete and more secure than with the other methods described.

A method for removing an installed thermo-plastic replacement pipe from an existing underground pipe will now be discussed in more detail below.

As noted previously, it is preferred that the thermoplastic pipe 10 be manufactured in the folded form shown in Figure 8. First cooled and cured in such a folded shape, the thermoplastic pipe retains a memory for such a shape, which tends to return to such a folded shape when reheated and unobstructed. This folded shape memory can be used to promote removal of a damaged portion of such a pipe from an existing underground conduit. To remove the damaged thermoplastic pipe from the inside of an existing pipeline, the damaged pipe is heated by passing fresh steam through it and, if possible, around the outside thereof. When hot, the damaged pipe section to be removed collapses to its original folded shape. This collapse and re-folding can be accelerated by connecting a vacuum pump to the interior of the pipe to reduce the internal pressure therein. When the hot plastic pipe is collapsed and folded, it can be pulled out of the existing pipeline by means of a cable winch with the pull cable attached to an accessible end of the collapsed pipe.

In the following, we will now further elaborate on heating and forming the thermoplastic pipe for introduction.

Heating the folded thermoplastic pipe for ease of insertion, especially where bends are to be made in the existing pipe or conduit, or where the new pipe is to be passed through a small, deep vertical hole, is important. Several methods of pre-heating have been described, including the use of a hot cabinet or a long steam tube. Another method is to heat the inside of the existing pipeline, into which the thermoplastic pipe must be fed. According to this method, a short pipe section with a steam connection is connected to the rear end of the existing pipe to be repaired. A curtain of cloth on the back of the steam pipe section is wrapped around the folded new pipe as it passes through the steam pipe joint into the existing pipe to heat the new pipe during its introduction. This method can also be used to promote the other heating methods described.

The flat, folded shape of the rigid thermoplastic pipe shown in Figures 3 and 8 is also important because such a shape imparts certain properties to the pipe which are inaccessible with other pipes which collapsed only overall to reduce their cross-sectional dimensions or can be partially collapsed for insertion into an existing pipe. First, the flat, folded shape shown, when heated and pliable, can be easily and compactly stored in long or short lengths on a spool. The coil, in turn, can be used for storage, reheating and piping the pipe.

Second, the pipe shape shown, when heated and pliable, can be introduced from a small vertical access opening, such as a manhole, around a sharp bend into a pipeline and installed around sharp bends in the existing pipeline itself. A rigid PVC pipe with a characteristic wall thickness-to-diameter ratio within the aforementioned range, when flattened and folded to the unique shape shown in Figures 3 or 8 and heated to a flexible state, will have a ratio of minimum bend radius to rounded outer diameter. from 1 to 2. That is, a typical rigid PVC pipe with a diameter of about 1 decimeter (4 inches) when flexible, flattened and folded as shown in Figures 3 or 8 can take a curvature with a radius of between 1 and 2 decimeters (4 and 8 inches), depending on the wall thickness, without damaging the pipe walls. Such a minimum bend radius is inaccessible with other known forms of rigid thermoplastic pipe when in their flexible states.

Third, despite the foregoing properties, when heated and bendable, the folded pipe shapes of Figures 3 and 8 can be quickly transformed into a round shape and hardened to make the pipe rigid in construction and strong enough to withstand external ground and hydraulic pressures. Therefore, the installed thermoplastic pipe of the invention is really a replacement pipe, not just a cover for a damaged existing pipe.

Claims (10)

A method of manufacturing a thermoplastic pipe in a reduced form, characterized by extruding thermoplastic pipe material while in a hot and moldable condition through a mold (118) to form the plastic material in a tubular condition of a desired size; feeding the resulting plastic tubular material while being held in a pliable condition by a gauge and mold calibrator to shape and retain the plastic material in the desired reduced form; and cooling the thermoplastic material in its reduced form to cure the thermoplastic material in this reduced form. An apparatus for manufacturing a length of substantially rigid thermoplastic pipe in a reduced form, all cross-sectional dimensions being smaller than the diameter of the pipe when it is tubular, and requiring heating to a temperature above room temperature to make it pliable, comprising: extruders for extruding a thermoplastic material into a length pipe of substantially tubular cross section; molding means for forming and holding the extruded thermoplastic pipe in a desired reduced form after exiting the extruding means; and winding means for winding up the pipe in a reduced form for storage, whereby the pipe keeps the reduced form when it is then reheated to make the pipe pliable. A method of installing a substitute pipeline of substantially rigid thermoplastic material at ambient temperatures in an existing pipeline, characterized by providing an access port (16, 98) to the existing pipeline in a reduced form that is expandable is to a tubular shape of a desired external diameter that is substantially the same as the internal diameter of the existing pipeline and that is manufactured in a collapsed and reduced form with the maximum size being less than the internal diameter of the existing pipeline; heating a length of the replacement pipe when it is in its collapsed and folded form to a longitudinally flexible state; inserting a front end of the replacement pipe into the existing pipe (14, 90, 94) when it is in such a heated bend state; placing the replacement pipe inside the existing pipe; rounding the replacement pipe from its folded form to a tubular form by applying heat and internal pressure to the collapsed and folded replacement pipe; and cooling the replacement pipe to stabilize it in the tubular shape, the existing pipeline being a side pipeline (90) connecting to a main pipeline (94), the replacement pipe (10) being fed from an access point (98) into the side pipeline the main pipeline, and that the replacement pipe is placed with pulley and cable members (152) in the existing pipeline, such that pulling from the access opening on a first end of a cable member (168) in a direction away from the main pipeline results in has the second end of the cable member pulling the front end of the replacement pipe to the main pipeline. The method of claim 3, characterized by limiting the ability for fluid to flow out of an orifice at the front end of the replacement pipe (10) prior to applying internal pressure for reforming the replacement pipe, to build up fluid pressure within the replacement pipe and internal passage of hot fluid by allowing the length of the replacement pipe, and then injecting a heated fluid into the replacement pipe from a rear end, at a temperature and pressure sufficient to cause the replacement pipe to expand its collapsed toe folded state to a round state. A method according to claim 4, characterized in that the fluid flow from the front end of the replacement pipe (10) is limited by plugging the front end with a flexible, foldable and inflatable plug (222), which is inside the collapsed and folded replacement pipe is worn. A method according to any one of claims 3, 4 or 5, characterized in that the replacement pipe (10) is manufactured in the reduced form by extruding the thermoplastic pipe material through a mold (118) in a hot plastic state around that material into a tubular shape of desired dimensions, prior to any significant cooling, feeding the resulting hot tubular thermoplastic material into the plastic state through the apertures (138) of a series of calibration plates (128) in which the apertures are given such shape and dimensions that the tubular material is collapsed and reduced to a predetermined reduced form, subjecting the plastic material to partial vacuum, the temperature being above the temperature at which memory is imparted to the thermoplastic material, then cooling the collapsed and folded pipe under the pull through and out of the calibration plates known to cure the pipe in the reduced form, reheating the collapsed and folded pipe to make it longitudinally flexible at a temperature below the temperature at which the memory characteristics of the thermoplastic material will be changed, and placing the flexible pipe in its collapsed and folded form in a storage condition in which the pipe is stored in layers. A method according to any one of claims 3 to 6, characterized in that the replacement pipe (10) is rounded with sufficient heat and with sufficient internal pressure to form pits (76) in the replacement pipe corresponding to the location of side joints (74), that the pit sections are determined and that a portion of the replacement pipe is removed at the pit section to make an access opening for a side joint. A method according to any one of claims 3 to 7, characterized by rounding the front end of the replacement pipe (10), attaching an expandable sealing sleeve around the rounded front end of the replacement pipe, refolding the front end before insertion of the replacement pipe, and heating, rounding and expanding the replacement pipe after placing the replacement pipe to firmly compress the sealing sleeve between the replacement pipe and the existing pipe. 9. Replacement pipe for insertion into an existing pipe, characterized by a length of substantially rigid thermoplastic pipe (10) in a reduced form so that the pipe retains a memory for this reduced form and is capable of being made flexible and expanding to a substantial tubular shape of a desired size, wherein the maximum size of the pipe in the reduced form is less than the size tubular shape. Replacement pipe for insertion into an existing pipe, characterized by a length of pipe (10) of a thermoplastic resin material such that the pipe at ambient temperatures is substantially rigid and predetermined elevated temperature is flexible and expandable to a substantially tubular shape of a desired size wherein the pipe has a flat and longitudinally folded shape connecting the first and second legs together at a rounded spherical longitudinal folded portion, the first and second legs of the folded pipe terminating at rounded spherical free ends defining fluid passages by the length of the folded pipe, one leg longer than the other so that the spherical end of the shorter leg nestles behind and in an overlapping relationship to the spherical end of the longer leg to minimize the total thickness of the folded pipe.