Methods for lining pipes and connecting the lined pipe with adjacent or lateral pipes

A section of a host pipe is removed, a flange is placed at one end of the host pipe section and split sleeve halves are secured to one another and at one end to the flange to cantilever the split sleeve from the end of the host pipe. A deformed thermoplastic liner is drawn through the host pipe and split sleeve and reformed to its cylindrical configuration by introducing steam under pressure. Once reformed, the split sleeve halves are removed, the end portion of the rerounded liner is cut and an adapter flange is fused on the end of the cut liner portion. The split sleeve halves are reapplied about the rounded liner with the flange on the adapter bearing against an end face of the flanges of the split sleeve. A cylindrical section is welded to the adjacent host pipe section and a flange thereof is bolted to the distal end flange of the split sleeve whereby a permanent pressure sealed connection is provided between a lined host pipe section and a non-lined host pipe section.

BACKGROUND OF THE INVENTION

The present invention relates to methods for lining pipes and connecting the lined pipe with adjacent or lateral pipes and particularly relates to methods for terminating liners to known dimensions to facilitate flanged or flared terminal connections with the adjacent or lateral pipes.

Methods for lining a host pipe, such as a concrete sewer line or a pressure pipe, with a thermoplastic liner are well known. One such system for lining pipes involves the manufacture of generally cylindrical pipe liners formed of extruded thermoplastic material. After extrusion, the cylindrical liners are shaped to reduce their cross-sectional envelope. Various methods and apparatus have been used to deform the initially extruded cylindrical liners into various cross-sectional configurations, for example, H, X, U and V cross-sections. A generally U-shaped liner, however, has been found to be most useful, practical and economical. Thus, the extruded cylindrical liner is shaped at the manufacturing site to a substantially reduced U-shaped cross-sectional configuration.

Subsequent to the manufacture of the deformed liner, the liner is typically coiled on a reel for transport to a job site. Alternatively, the deformed liner may be transported in linear lengths to the job site. At the job site, the deformed thermoplastic liner is conventionally pulled inside a pipe to be lined, i.e., a host pipe and the liner is then restored to its initially extruded cylindrical configuration with its outer cylindrical surface bearing against the interior cylindrical surface of the host pipe wall. The restoration of the deformed liner to its original cylindrical configuration is often carried out by the introduction of steam into the liner while in the host pipe whereby the liner is reformed to its cylindrical configuration and lines the host pipe. A well known system for lining pipes with a generally U-shaped liner which is reconfigured into a cylindrical liner upon installation is disclosed in various patents, namely U.S. Pat. Nos. 4,985,196; 4,863,365; 4,986,951; 4,998,871; 5,342,570; and 5,091,137, the subject matters of which are incorporated herein by reference.

To line underground pipes, particularly pressure pipes, i.e. pipes for transmitting fluid under pressure, it is important to provide terminal ends of the liner with known dimensions, e.g. inner and outer diameters and wall thicknesses. The dimensions of the liner when rerounded from the generally U-shaped configuration to a cylindrical configuration lining the host pipe cannot be controlled absent containment or constraints. Otherwise, the wall thickness of the uncontained and unconstrained liner will vary and the pipe may blow out entirely. Also, the inner and outer diameters of the liner cannot be controlled. It will be appreciated that the end of the liner must be flared or provided with known dimensions so that additional liner sections can be fused to the liner end. This is particularly important when lining pressure pipes which require the space between the inner diameter of the host pipe and the outer diameter of the liner to be sealed and particularly at the pipe joints. Otherwise the pressure of the fluid within the lined pipe could destroy the liner. Accordingly, there has developed a need for providing a method of terminating liners, preferably for underground pipe lines, which may or may not be pressure lines, to known dimensions such that flanged or flared terminal connections can be provided to adjacent or lateral pipes.

BRIEF SUMMARY OF THE INVENTION

In a preferred embodiment of the present invention, there is provided a method of lining a host pipe having a cylindrical cross-section and connecting the lined pipe with an adjacent pipe comprising the steps of: (a) securing a split sleeve to an end of the host pipe to form a generally axial cylindrical extension thereof, the split sleeve including longitudinally extending sleeve halves; (b) providing a liner having a non-cylindrical cross-section within the host pipe and the split sleeve; (c) reforming the non-cylindrical liner within the host pipe and the split sleeve to generally conform the liner to the inner diameters of the cylindrical host pipe and the split sleeve; (d) removing the split sleeve halves from about a reformed end portion of the liner within the split sleeve; (e) cutting the liner end portion to a predetermined length; (f) providing a flange on the end of the reformed cut liner end portion; (g) securing the split sleeve about the cut liner end portion; and (h) securing the adjacent pipe or an extension of the adjacent pipe and the split sleeve to one another at an end of the split sleeve remote from the end of the host pipe and with the liner end portion flange between the split sleeve and the adjacent pipe.

In a further embodiment of the present invention, there is provided a method of lining a host pipe having a cylindrical cross-section and connecting the lined host pipe with a lateral pipe, comprising the steps of: (a) removing an intermediate section of the host pipe at a location in general registration with the lateral pipe leaving spaced opposed ends of the host pipe; (b) removing an end portion of the lateral pipe and forming a connecting end thereon; (c) securing a split sleeve to the opposed ends of the host pipe to form a continuation of the host pipe, the split sleeve including longitudinally extending halves; (d) inserting a thermoplastic liner having a non-cylindrical cross-section into the host pipe and split sleeve; (e) reforming the liner within the host pipe and split sleeve to generally conform the liner to the inner diameter of the cylindrical host pipe and the inner diameter of the split sleeve; (f) removing at least one of the split sleeve halves thereby generally registering a side portion of the reformed liner and the connecting end of the lateral pipe with one another; (g) fusing a thermoplastic pipe section to the registering side portion of the liner; (h) forming an opening in the side portion of the reformed liner in communication with the pipe section fused to the liner; (i) securing a third split sleeve half between said opposite ends of the host pipe and overlying the registering side portion of the reformed liner, said third split sleeve half having a lateral pipe extension receiving the thermoplastic pipe section fused to said liner; (j) securing a flange to a distal end of the fused pipe section; and (k) securing the connecting end of the lateral pipe to the lateral pipe extension with the flange therebetween.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawing figures, particularly toFIG. 1, there is illustrated a host pipe generally designated10and which host pipe is to be lined with a thermoplastic liner12. The host pipe10and an adjacent pipe14typically comprise underground sections of a run of a unitary pipeline in which an intermediate section of the pipe run has previously been removed from the pipe run to facilitate lining the host pipe10and securing the lined host pipe to the adjacent pipe14. The host pipe10thus requires lining while the remaining section, i.e. the adjacent pipe14, may or may not require lining. Also, while a flange16is illustrated inFIG. 1at the end of the host pipe10and a flange18(FIG. 5) is secured to the adjacent pipe14, typically the flanges16and18are applied in the course of lining the host pipe and connecting the host pipe and adjacent pipe to one another as described below. There are, however, existing pipe lines which terminate in an underground manhole and have existing flanges at their ends which may be utilized in the course of lining one or both of the pipes.

The present invention is particularly applicable to metal pressure pipes, i.e. pipes carrying a fluid under pressure, although it will be appreciated that the method described herein can be employed in non-pressure pipes. Also, the apparatus and methods disclosed herein are particularly applicable to underground pipes, although they may be used in other environments. Thus the drawing figures illustrate the pipes12and14and the split sleeve30in an underground trench T.

As illustrated inFIG. 1, the host pipe10and adjacent pipe14are generally cylindrical in cross-section and are formed of metal in pressure pipe applications. The host pipe10is also illustrated being lined with the deformed liner12. Liner12may be formed of a thermoplastic material. e.g., polyethylene at a manufacturing site where the liner is extruded into cylindrical cross-sections and deformed to reduce its cross-sectional envelope so that the liner12can be received in and passed through host pipe and subsequently rerounded or returned to its original cylindrical cross-sectional configuration into contact with the inner diameter walls of the host pipe. Apparatus and processes for forming the thermoplastic liner12and installing the liner in host pipes are described and illustrated in the above-identified U.S. patents. Suffice to say that the reduced cross-sectional configuration of the liner12may be of a variety of non-cylindrical shapes, such as H, U, C and V shapes. The present description of the invention, however, goes forward using the U-shaped configuration as an exemplary embodiment of this aspect of the invention and as an example of the various other cross-sectional shapes of the liner which may be utilized.

Referring toFIG. 2, the deformed liner12has a cross-section including a pair of side lobes20which straddle a single radially inwardly directed central lobe22forming the generally U-shaped cross-sectional configuration. When a liner having this generally U-shaped cross-sectional configuration arrives at an installation site, typically but not necessarily carried on a reel from the manufacturing site to the installation site, the liner may be uncoiled from the reel and drawn into the host pipe from one end and along the host pipe and a split sleeve30(FIG. 1) connected to the host pipe end. InFIG. 1, the liner12is illustrated as having been drawn through the host pipe10and an end portion of the liner is illustrated passing through the split sleeve30and projecting from an end of the split sleeve30.

To obtain terminal portions of the liner of known dimensions, e.g. known wall thicknesses, and inner and outer diameters, in accordance with a preferred aspect of the present invention and prior to drawing the liner through host pipe10, the split sleeve, is initially secured to the end of the host pipe10. The split sleeve30includes a pair of longitudinally extending semi-cylindrical sleeve halves32and34, each having longitudinally extending flanges36and38respectively along their margins. Additionally, each half32and34of the split sleeve30includes end flanges. For example, split sleeve half32includes flanges40and42at opposite ends respectively while split sleeve34includes flanges44and46at opposite ends. It will be appreciated that the flanges40,42,44and46are semi-circular. The marginal flanges36and38are provided with bolt holes to enable securement of the split halves32and34to one another. Flanges40,44and42,46likewise have bolt holes to enable respective securement to the flanges16and18at the opposed ends of the host pipe10and adjacent pipe14. InFIG. 1, the split sleeve halves32,34are illustrated secured to one another and are also secured at one end to host pipe10, e.g. by bolting flanges40,44to the flange16of the host pipe10. It will be appreciated that the flange16may be welded directly to the end of host pipe10or form part of a pipe section terminating in flange16and welded to the end of the host pipe10. Consequently the split sleeve30forms a generally axial cantilevered cylindrical extension of the host pipe10when secured thereto. Upon drawing liner12through the host pipe10and split sleeve30, the split sleeve30surrounds the non-cylindrical, non-reformed end portion of the liner12projecting from host pipe10. While preferably the split sleeve is secured to the host pipe prior to drawing liner10through the host pipe and split sleeve, the liner may be initially drawn through the host pipe and the split sleeve subsequently applied about a projecting end portion of the liner and secured to the host pipe flange16.

With the split sleeve30about the end of the deformed, liner12, connections, not shown, are made at opposite ends of the liner, to introduce a fluid, preferably steam, under pressure to reform or reround the liner12within the host pipe10and split sleeve30into a generally cylindrical configuration as illustrated inFIG. 3. Thus, the liner is rerounded in both the host pipe and the split sleeve.

With the liner rerounded within split sleeve30, the split sleeve halves32and34are disconnected from one another and from the flange16of host pipe10and removed as illustrated by the set of arrows37inFIG. 4. It will be appreciated that the liner which was previously reformed within the split sleeve now exhibits inner and outer diameters and a wall thickness of known dimensions. It will also be appreciated that it is possible to cut the end of the liner projecting from the split sleeve without removing the split sleeve so that a flared flange may be formed on the end of the liner. Using a flaring tool, the end of the liner can be heated and flared back to overlie the axial end face of the flanges42,46of the split sleeve30enabling direct connection between the flanges42and46of the split sleeve and the flange18of the adjacent pipe. However, this is very often difficult to achieve since the dimensions of even a small axial length necessary to form a flared portion cannot be controlled and the formation of a seal between the split sleeve becomes problematical.

Therefore, the split sleeve halves32and34are preferably removed from the reformed liner12as illustrated by the arrows at37inFIG. 4. Upon removal, the reformed liner end portion is cut back to a predetermined dimension (A) from the host pipe end. Since the cut back projecting end portion of the liner is of known dimensions, i.e. length, inner and outer diameters and wall thickness, a thermoplastic adapter50(FIG. 4) having a cylindrical extension52and a flange54formed at one end may be fused to the reformed liner end portion. Given the known dimensions of the cut liner end portion (including length (A) and the longitudinal length (B) of the split sleeve, adapter50can be preformed or cut to the appropriate length (B) such that the adapter flange54can be positioned accurately to bear against the axial end face of the split sleeve as illustrated inFIG. 5. It will be appreciated that since the adapter is50preformed to known dimensions, the dimensions of the flange54are accurately controlled. In the alternative, the reformed liner end portion may be cut exactly flush with the axial end face of the flanges42and46. A flange similar to flange54but without the cylindrical extension52can then be fused on the end of the liner such that the fused flange is located a predetermined distance from the flange16of the host pipe, i.e. is positioned to fit snugly against the end face of the flanges42,46of the split sleeve30. As indicated previously, the split sleeve halves32and34are then reapplied about the rerounded liner12as indicated by the set of arrows39inFIG. 4, secured to one another by bolts passing through the flanges36,38and secured to the host pipe by bolts passing through flanges40,44and flange16. The flange54thus accurately bears snugly against the axial end face of flanges42,46of the split sleeve30. Note that the outer diameter of the flange54is less than the inner diameter of the bolt circle on the flanges42,46.

To connect the adjacent pipe14to the lined host pipe10and split sleeve30, the adjacent pipe14may be initially or later cut back and a pipe section60terminating in flange18may be welded to pipe14. It will be appreciated that the welded section60is of predetermined axial length to close the gap between the end of pipe14with the pipe section60secured thereto and flanges42,46. With the flanges42,46and18bolted to one another and the trench T filled in, the installation is complete.

It will be appreciated that the flange54forms a seal bearing against both axial end faces of flanges42,46and18preventing the pressure of fluid, flowing through the lined host pipe and split sleeve30and into pipe14from leaking into areas between the liner12and the host pipe10and split sleeve30. The split sleeve, of course, remains as part of the underground pipe run since it forms part of the pressure containment for the portion of the liner within the split sleeve.

Referring now toFIGS. 6–11, there is illustrated a system for connecting a lined host pipe, e.g. a lined pressure pipe with a lateral70. In this embodiment like reference numerals are applied to like parts as in the preceding embodiment followed by the letter a. In this embodiment, a host pipe10a, e.g. a pressure pipe, is lined with a thermoplastic liner12aas in the prior embodiment and connected to the lateral pipe70which may be lined or not lined. To accomplish this, a section74of the host pipe10aincluding a section76of the lateral pipe70is removed from the host pipe10a. As in the preceding embodiment, split sleeves32aand34a(FIG. 7) are secured to one another and to end flanges16aand18aformed on the registering end portions of the host pipe10a. The flanges16aand18amay be welded onto the host pipe sections with or without cylindrical extending portions. With the split sleeves32aand34asecured to the host pipe10aand adjacent pipe14a, the liner12ais drawn through the host pipe10asplit sleeve30aand adjacent pipe14a, and reformed to its original cylindrical configuration. Once reformed, the split sleeve half e.g. half32ain registration with the lateral pipe70is removed. A lateral extension76formed of thermoplastic material is fused to the rerounded liner12aexposed by the removal of the split sleeve half32a. The portion78of the liner12awithin the fused margin of sleeve76is then removed by inserting a tapping tool through sleeve76.

Referring now toFIG. 9, a third split sleeve half80similar to split sleeve half32aexcept that it has a lateral metal extension82terminating in a flange84is applied about the rerounded liner12awith the sleeve76being received within the extension82. The split sleeve80is then bolted to split sleeve34aand to the end flanges16aand18athus permanently enclosing the rerounded liner portion within the split sleeve.

Referring toFIG. 10, the terminus of the sleeve76is cut and flared using a flaring tool, not shown, to form a flange88on the end of the sleeve in axial abutment against the end face of the flange84and radially within the bolt circle of flange84. InFIG. 10, a pipe section90is secured to the lateral pipe70, for example by welding at a seam line92, the pipe section90terminating in a flange94. The flanges84and94are then bolted to one another sealing the flange88between the flanges84and94. It will be appreciated that the extension82on the split sleeve80constrains or confines the thermoplastic sleeve portion such that the fluid under pressure flowing through the lined host pipe and through the thermoplastic sleeve76of the lateral70remains sealed and does not blow through the liner.

In a further embodiment illustrated in drawingFIGS. 12–14, wherein like reference numerals are applied to like parts as in the preceding embodiments followed by the letter “b”, there is illustrated an alternative for connecting a lined host pipe10bwith a lateral pipe70bwherein the pipes are pressure pipes. After rerounding the liner within the host pipe10band the adjacent pipe14bwith a split sleeve arrangement similar to split sleeve30a, removal of one of the split sleeve halves and fusing a thermoplastic sleeve76bto the rounded liner, a split sleeve half80bsimilar to split sleeve half80illustrated inFIG. 9is secured to the split sleeve half34bwith the thermoplastic sleeve76bprojecting through and from the end of extension82b. The sleeve76bmay then be cut and a thermoplastic flange adapter92having a flange94on one end may be fused to the end of the cut sleeve76b. The sleeve76bis cut and the length of the flange adapter92is formed such that the distance between flange94of the adapter92and the flange84bon extension82bis known. A split sleeve30bhaving a similar length dimension and inner diameter corresponding to the outer diameter of the sleeve76bis bolted about the sleeve76band to flange84b. That is, split sleeve halves96and98are bolted to one another and at one end to the flange84b. The adapter flange94thus lies flush against the axial end flanges of the split sleeve30bat its distal end. A cylindrical extension100preferably formed of metal is then secured, e.g. by welding, to the cut end of the lateral pipe70band terminates in a flange102. The extension100is sized to have a length precisely fitting between the lateral70band the distal end flange of the split sleeve30b. When the split sleeve30band extension flange102are bolted up with the adapter flange sealing therebetween, a sealed pressure fluid connection is thus formed for communicating pressure fluid through the lined host pipe and the lateral.