Corrugated plastic pipe sections having flanged ends and structurally tight joints thereof

Abstract

Corrugated plastic pipe sections having a flanged end formed by a circumferential portion of an end corrugation or section of the pipe liner and a method and kit for joining flanged end corrugated plastic pipe sections are described in a system in which a portion of the end currugation or pipe liner forms a flange and a peripheral flange clamp straddles flanges and draws the flanges together to provide a structurally sound joint. A gasket may be interposed between flanges or the flange periphery and the clamp. The invention achieves a cost effective tight joint, allows field cuts of the corrugated plastic pipe and the fabrication of fittings from corrugated pipe sections and provides a selectable pipe size reducer coupling for corrugated plastic pipe.

Description

TECHNICAL FIELD

[0001] This invention relates to corrugated polyethylene pipes and a joint system therefor for larger diameter pipes (greater than 2 inch diameter). The invention provides a robust and cost effective mechanically secure and water tight joint, depending on configuration and application, that reduces infiltration and ex-filtration in an installed pipe system. The invention overcomes hydraulic effects and ground shift short falls encountered in present PVC, concrete, and HDPE pipe systems that result in the separation and/or misalignment of bell and spigot joints, causing the joints to leak, excessive infiltration and tree/plant root penetration into sanitary sewer and septic systems, especially in the lateral lines, and infiltration and ex-filtration in highway drainage systems. The joining system of the invention is adapted to High Density Polyethylene (HDPE) pipe and provides chemical resistance to sewer gases, animal and industrial waste, and provides the capability of longer and variable pipe lengths that decrease the number of joints per line. The invention expands the utility of HDPE pipe in drainage, agriculture, highway, sanitary sewer, waste water reuse, irrigation, industrial waste, animal waste, fiber optics, and utility cable applications.

BACKGROUND ART

[0002] Large diameter corrugated plastic pipe sections (typically formed from polyethylene) are known products. Past and present attempts to design water tight joints for corrugated plastic pipe to expand the use of the pipe to drainage and sanitary sewer applications typically involve radial compression of a gasket (molded or extruded and spliced) that occurs when an end section of the pipe formed as a spigot is inserted into a corresponding end section of a pipe formed into a bell. Pushing a spigot, with a gasket wrapped around its exterior cylindrical surface, into a bell having a tapered internal surface and interference fit, typically provides the radial compression of the gasket. The motion of pushing the gasket on the spigot in an axial direction and the frictional force on the interior lateral surface of the bell may cause the gasket to un-seat, twist and roll. In addition, circumferential tensile stresses on the interior of the bell, required to maintain gasket compression, decrease the stress crack resistance of the plastic pipe. A gasket is typically located in either a groove on the crest or crown or in the root of a corrugation near the pipe end of the pipe section. In the prior case the stiffness of the corrugation is not sufficient to withstand the hydrostatic water pressure required to prevent water leaks. As a result the corrugations supporting the groove that locates the gasket are sometimes made stronger by injecting rigid foam inside the corrugation. The latter case requires banding or other strengthening to avoid the large stresses that cause stress cracking. Both solutions add considerable cost to obtain a reliable water tight joint. Bell and spigot joints rely on the compression of a radial gasket and have the additional disadvantage that internal pressure acts on the axial projected area of the wetted portion of the gasket causing a “hydraulic effect” that acts to open the joint.

[0003] A further disadvantage of joints that utilize radial compressed gaskets is that the joints are subject to failure, leaking water under pressure, as a result of rolling and twisting of the gasket, or by stress cracking of the bell. William C. Andrick in U.S. Pat. No. 5,687,976 describes a symmetrical gasket for pipe joints that seals against both internal lateral surface of a bell and external lateral surface of a pipe having transverse corrugations. James B. Goddard in U.S. Pat. No. 5,765,880 discloses a bell and spigot joint for helical double wall corrugated pipe. Kenichi Hattori in U.S. Pat. No. 4,871,198 discloses a clamp type corrugated plastic pipe coupling in which a rubber gasket is utilized in radial compression to seal the joint. In the latter case, the metal clamp reduces the stress-cracking problem. However, the gasket transfers stress to the plastic inner wall or liner and to the corrugations. Both the corrugations and the liner are relatively low in stiffness and have difficulty maintaining the radial compression of the gasket. The high creep behavior of semi-crystalline polymers such as high-density polyethylene is responsible for increased leaking due to aging. It may also be difficult to assemble a joint as described by Hattori when the pipe sections to be joined are located in an open trench. Another disadvantage is the relatively high cost associated with an extended cylindrical gasket and a metal clamp. Bell and spigot type joints have an additional disadvantage insofar as field cuts of sections of corrugated pipe are not possible.

[0004] My co-pending applications for patent in the United States Patent and Trademark Office, “Joint and Seal for Large Diameter Corrugated Plastic Pipe and Method for Joining Plastic Pipe Sections,” Ser. No. 09/597,338 filed on Jun. 19, 2000; “Water tight Joint and Method of Sealing Drainage and Sanitary Sewer Pipe Sections,” Ser. No. 09/788,913 filed on Feb. 19, 2001; and “Method and Joint Design for Infield Water Tight Sealing of Dual Wall Corrugated Plastic Pipe Sections,” Ser. No. 091794,638 filed on Feb. 27, 2001 detail the characteristics and properties of corrugated polyethylene/plastic pipe and problems encountered by the prior art in attempting to effect a water tight seal between adjacent pipe sections. In my co-pending applications for patent, I disclose, inter alia, a method and design that avoids both the rolling of the gasket and stress cracking by utilizing a portion of the end corrugation to provide a means for self-energizing a water tight seal for joining two abutting sections of pipe. The present invention reduces the cost and complexity of producing secure tight joints in HDPE corrugated pipe.

[0005] Typically, soil tight performance in corrugated plastic drainage pipe is obtained by a compressing a gasket having a relatively small cross section when compared to the height and longitudinal width of a transverse corrugation. A transverse ridge at the crown of the end corrugation (referred to as a spigot) typically supports a joint gasket. The locating seat (transverse ridge) on the end corrugation has a disadvantage in that formation of the spigot requires a thermoforming mold to be introduced in the corrugation process and the other end of the corrugated plastic pipe either requires a molded bell at the end or necessitates the use of a dual bell coupler. This approach suffers from the weakness of the walls the corrugation supporting the crown of the corrugation and the gasket plus the cost associated with manufacturing in-line bell and spigot couplers. The present invention has the advantages of eliminating the requirement to introduce a bell and spigot mold pair that avoids the cost of the bell and spigot mold and of increasing the production rate of the pipe by removing the need to reduce production rates while forming of the bell and spigot.

[0006] The majority of existing drainage and sanitary sewer systems utilize reinforced concrete, polyvinyl chloride (PVC) and corrugated polyethylene pipe having bell and spigot joining systems. The bell and spigot joining systems typically function by radial compression of a peripheral gasket located between mating bell and spigot. When properly mated bell and spigot gasket systems provide some protection against infiltration and ex-filtration. However, shifts in the soil, changes in soil conditions, and seismic occurrences cause the bell and spigot joints to misalign and/or open sufficiently, causing infiltration under wet conditions and ex-filtration under dry conditions. Infiltration is responsible for tree root penetration that causes blockage. Post installation, bell and spigot joining systems have the disadvantage of internal hydraulic pressure exerting forces on the wetted projected area of the radially compressed gasket, separating the pipe ends. These factors are responsible for infiltration and ex-filtration causing excessive wastewater treatment costs and pollution of our national waterways respectively. The invention advantageously supplies a rigid joining system for corrugated plastic pipes resulting in rigid joints in chemically resistant flexible pipes capable of accommodating shift in the soil and/or back fill without breakage in the pipes or the joints.

DISCLOSURE OF THE INVENTION

[0007] The invention comprises corrugated plastic pipe sections having a flanged end formed by a circumferential portion of an end corrugation or the pipe liner and a method and kit for joining corrugated plastic pipe sections to create a structurally sound joint that may be adapted for applications where soil and water tight joint properties are required. In the system of the invention, a portion of the end corrugation or pipe liner forms a flange at the end of each pipe to be joined; a clamp straddles the outside lateral surfaces of the two flanges and draws the flanges together. A joint is thereby formed. An annular elastomeric gasket may be inserted contacting the facing surfaces of the pipe flange and a second flange at the end of another pipe or fitting, or the radially peripheral side edges of the flanges. The invention achieves a cost effective structurally sound joint, allows field cuts of the corrugated plastic pipe and the fabrication of pipe fittings and connectors from corrugated pipe sections with limited modification to the molding process.

[0008] An object of the invention is to provide a tight joint by providing a flange at the end of the corrugated plastic pipe from a circumferential portion of the end corrugation, thereby avoiding the need and expense associated with molding separate bell and spigot or dual bell couplers. It is a further object of the invention to provide a section of corrugated plastic pipe having a flange at its end formed from a section of a corrugation, the liner and/or from both the liner and the corrugation. It is also an object of this invention to provide a section of corrugated plastic pipe joined to an abutting section of corrugated plastic pipe or a fitting having a flange at its end by inserting a gasket between the abutting flanges and utilizing a clamp to axially compress a gasket to form a water tight seal. An external rigid clamp supports the relatively weak flange eliminating the need to stiffen the end of the corrugated pipe by injecting rigid foam into the end corrugations.

[0009] The external rigid clamp acts as a rigid coupler that prohibits post installation separation of the joined pipe ends caused by ground shifts, changes in soil conditions and seismic occurrences. This invention prevents infiltration, ex-filtration and pipe separation by rigidly coupling the pipe ends by applying an external rigid flange clamp that axially compresses the gasket by applying pressure to the flange at the end of the corrugated plastic pipe from a circumferential portion of the end corrugation.

[0010] Once pipe ends are locked together the pipe must be compliant to prevent fracture of the pipe when the earth shifts; if the pipe ends are not locked together, they misalign and/or separate. Because PVC and concrete pipes are rigid, the bell and spigot joints accommodate the ground shifting by joint misalignment and potential separation. As a result, pipe integrity is sacrificed for joint integrity. The invention comprises a rigid joining system for corrugated plastic pipes in which the joint provides a permanent rigid fixation between adjacent pipe sections and, over the run of a pipe line, provides sufficient flexibility to accommodate ground shifts. At present, the corrugated plastic pipe industry utilizes bell and spigot and welded joining systems. In the former case, ground shifts and hydraulic effects compromise joint integrity; in the latter case, the costs of welding are prohibitive.

[0011] The present application also discloses a kit for providing a water tight seal between adjacent (abutting) sections of corrugated plastic pipe or fittings comprising a gasket and a flange clamp adapted to form the joint. In a further object, the invention comprises a design for and method of using fabricated fittings to join flanges on the end sections of corrugated pipe that are formed from circumferential portions of the pipe corrugations and/or liner. Presently fabricated fittings typically require pipe ends that have bell shapes or spigot shapes and may require dual bell couplers. The present invention eliminates the need for specially formed ends and couplings and allows corrugated pipe to be manufactured without introducing coupling molds into the forming process, thus saving the money associated with utilizing specially molded bells and spigots for fittings. The invention eliminates the need for bell and spigot ends on sections of corrugated plastic pipe and fittings and eliminates the need for internal and external dual bell couplers.

[0012] Presently stepped reducing “Y”, “T” and four way fittings are fabricated for single wall corrugated pipe. This has been accomplished by roto-molding and by blow molding fittings with several diameter bells in series. This practice allows the pipe manufacturer to supply a universal fitting that is adapted in the field by the installing contractor, who simply cuts off the fitting at the bell diameter of his choice. It is a further object of this invention to disclose stepped fittings for dual wall corrugated plastic pipe that utilize flanges of varying diameters. This invention discloses a molded, stepped, selectable diameter, and offset reducer coupling that provides a means of forming a water tight joint with corrugated plastic pipe and plastic and none plastic pipe sections having different diameters and flange ends. Furthermore it is the object of this invention to disclose a molded fitting design with an integral stepped, selectable diameter, and offset reducer coupling for joining corrugated plastic pipe having flange ends and the same and different diameters in a water tight fashion.

[0013] The enhanced joint design and method of fabricating soil tight and water tight joints disclosed is cost effective, allows field cuts of corrugated plastic pipe, and simplifies in-plant fabrication of flanged end fittings from sections of corrugated pipe. A clamp is utilized to compress the annular gasket by drawing the two flanges together. This invention utilizes a portion of the end corrugation or liner to provide an interior surface to compress a rubber gasket and an exterior surface against which the clamp radially pushes inwardly.

[0014] A further object of the invention is to offer a solution to environmental protection and pollution containment issues. The invention is directed to the subject of an enhanced water tight joining system for corrugated plastic pipe that rigidly couples pipe end having a flange formed by the end corrugation inserting a gasket and applying a flange clamp and addresses, inter alia, the problems identified below that adversely affect the environment:

[0015] The Fact Sheet presented at the 1995 Navy Pollution Prevention Conference On The Investigation and Rehabilitation of Sewer Systems by Ellen K. Brown of the Engineering Field Activity Northwest of the Naval Facilities Engineering Command, states “When a sewer system is brand new, it is fairly tight against extraneous infiltration and inflow, but not perfectly so. Even new systems experience a 5% increase in flows during wet weather. Over time, many biological, chemical and physical forces act on the sewer pipes to reduce their integrity. In active seismic zones, ground shifts can cause pipes to become misaligned, opening gaps at joints or causing breaks. Construction activity above the line can have similar effects. Underground springs can undermine the pipe allowing it to sag and open joints. Hydrogen sulfide produced in the sewer can eat away the crown of concrete pipe. Root intrusion at joints and cracks can wedge open pipelines. Poorly made lateral connections can weaken a pipe or leave a gap around the connection.”

[0016] Infiltration and ex-filtration in drainage pipe systems caused by leaky joint systems contribute to increased cost of water treatment and contamination respectively. “The Uniteds States Environmental Protection Agency (2000) identified sediment as the most widespread pollutant in the Nation's rivers and streams, in that sediment affects aquatic habitat, drinking water and treatment processes and recreational uses of rivers, lakes and estuaries.” A Synopsis of Technical Issues for Monitoring Sediment in Highway and Urban Runoff by Gardner C. Bent, John R. Gray, Kirk P. Smith and G. Douglas Glysson, Open-File Report 00-497 prepared in cooperation with the Federal Highway Administration, U.S. Department of the Interior, U.S. Geological Survey.

[0017] The system of the invention is intended to reduce the occurrence and severity of these problems and to provide joints for corrugated plastic pipes meeting the following specifications: ASTM-D 3212-96a, Standard Specification for Joints for Drain and Sewer Plastic Pipes Using Flexible Elastomeric Seals, 10.8 psi for 10 minutes, with an anticipated performance of >30 psi continuous & structural; ASTM-C 443-01, Standard Specification for Joints for Circular Concrete Sewer and Culvert Pipe, Using Rubber Gaskets, 13 psi for 10 minutes within 24 hours, moisture or beads of water acceptable, with an anticipated performance of >30 psi continuous, zero leakage; and to provide performance improvements over concrete pipe systems covered by ASTM-C 1103-94, Standard Practice for Joint Acceptance Testing of Installed Precast Concrete Pipe Sewer Lines, 3.5 psi with <1 psi drop in 5 seconds, with an anticipated performance of 0 psi drop; ASTM-C 969-94, Standard Practice for Infiltration and Exfiltration Acceptance Testing of Installed Precast Concrete Pipe Sewer Lines, 200 gal./in. (of internal diameter) (mile of sewer) (24 h), with an anticipated performance of zero leakage; ASTM-C 118-99, Standard Specification for Concrete Pipe for Irrigation or Drainage, 10 psi for 10 minutes without excessive leakage through wall of the pipe and transient ˜50 psi without cracking through pipe wall, with an anticipated performance of >40 psi continuous.

[0018] In brief, it is an object of the invention to provide a system for corrugated HDPE pipe useful in the sanitary sewer and drainage markets currently serviced by the concrete and PVC pipe industries, providing product differentiation, lower production costs and higher margins by one product offering zero in and zero out rigid joining systems that maintain joint alignment and prevent pipe separation between corrugated HDPE pipe sections. The joint system along the length of the pipe line allows sufficient flexibility to accommodate post installation ground shifts. As measured on the total cost of waste water treatment—instead of pipe and installation cost—the corrugated HDPE pipe joint system provides a major over all cost advantage over concrete and PVC sanitary sewer pipe as viewed by county and municipality engineers responsible for total operating costs. As a low cost drainage pipe providing zero in and zero out performance, the corrugated HDPE pipe system will contribute to reducing sedimentation of highway runoff that is identified by EPA and other organizations as the principal cause of contamination of the nation's waterways. Use of the system of the invention will open the use of corrugated HDPE pipe in new markets such as waste water reuse, irrigation, industrial waste, animal waste, fiber optics, and utility cables.

[0019] To the extent that existing pipe systems utilized in drainage and sanitary sewer applications allow infiltration under wet conditions and exfiltration under dry conditions resulting in excessive waste water treatment costs and pollution of our national waterways caused by leaky pipes and joining systems, the invention provides a robust cost effective pipe and joining system providing zero in and out performance, flexibility along an extended pipe length with a secure and reliable mechanism for the mechanical connection of pipe sections.

[0020] The invention is described more fully in the following description of the preferred embodiment considered in view of the drawings in which:

BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a cross section of two sections of dual wall corrugated plastic pipe having flanges at their ends formed from a section of the circumferential portion of an end corrugation.

[0022] FIG. 2 is a cross section of two sections of single wall corrugated plastic pipe having flanges at their ends formed from the circumferential portion of an end corrugation segment.

[0023] FIG. 3 is a cross section of two sections of dual wall corrugated plastic pipe having flanges at their ends formed from a circumferential portion of the inner wall or liner extending from the end.

[0024] FIG. 4 is a cross section of two sections of dual wall corrugated plastic pipe having flanges at their ends formed from a circumferential portion of the inner wall or liner and a section of (namely, a partial segment of material) what would otherwise form an end corrugation.

[0025] FIG. 5A is a cross section of a joint between abutting ends of two sections of dual wall corrugated plastic pipe utilizing a wedge shaped gasket between the abutting ends and a circumferential or perimeter flange clamp.

[0026] FIG. 5B is a cross section of a joint between abutting ends of two sections of dual wall corrugated plastic pipe utilizing an “O” ring gasket between the abutting ends and a flange clamp.

[0027] FIG. 5C is a cross section of a joint between abutting ends of a section of dual wall corrugated plastic pipe and a section of rigid pipe having a flange end utilizing a flat gasket between the abutting ends and a perimeter flange clamp.

[0028] FIG. 5D is a cross section of a concrete pipe with a mortared metal flange joined to a corrugated plastic pipe utilizing a gasket and a flange clamp.

[0029] FIG. 5E is a cross section of a joint between abutting ends of two sections of dual wall corrugated plastic pipe utilizing an “O” ring gasket and an inverted wedge shaped flange clamp.

[0030] FIG. 6A shows a cross section of a joint between two sections of corrugated plastic pipe having flange ends, utilizing an external gasket that straddles the abutting flanges and a circumferential or perimeter flange clamp having split annular plates.

[0031] FIG. 6B shows a cross section of a joint between two sections of corrugated plastic pipe having flange ends, utilizing an internal gasket between the abutting flanges and a flange clamp having a pair of split annular plates.

[0032] FIG. 7A shows the front view of a flat gasket utilized between flanges. and FIG. 7B shows the side view of the gasket.

[0033] FIG. 7C shows the front view of a wedged gasket between flanges and FIG. 7D shows the side view of the gasket.

[0034] FIGS. 7E and FIG. 7F respectively show the front and side views of an “O” ring gasket between flanges.

[0035] FIG. 7G and FIG. 7H respectively show the front and side views of an external inverted “V” gasket.

[0036] FIG. 8A and FIG. 8B respectively show the front and side views of a typical single element “V retainer circular” flange clamp utilized to draw the flanges together and compress the gasket.

[0037] FIG. 8C and FIG. 8D respectively show the front and side views of a typical three-segment “V retainer” circular flange clamp utilized to draw the flanges together and compress the gasket.

[0038] FIG. 8E and FIG. 8F respectively show the front and side views of a typical three-segment “inverted wedge” circular flange clamp utilized to draw the flanges together and compress the gasket.

[0039] FIG. 8G and FIG. 8H respectively show front and side views of a joint utilizing a lever or toggle clamp.

[0040] FIGS. 8I and 8J respectively show top and front views of a circular flange clamp having a ratchet mechanism for locking in the tightened configuration and tool for tightening the circular flange clamp.

[0041] FIG. 9A and FIG. 9B respectively show the front and side views of a circular flange clamp having two spilt plates.

[0042] FIG. 10A is cross sectional view of adjacent ends of dual wall corrugated plastic pipe sections having end flanges formed from circumferential portions of end corrugations.

[0043] FIG. 10B is a cross sectional view of two end sections of dual wall corrugated plastic pipe, a wedged shaped gasket and a circular flange clamp before final assembly.

[0044] FIG. 10C is a cross sectional view of a section of an assembled soil tight and water tight joint composed of two flange ends of dual wall corrugated plastic pipe, a wedged shaped gasket and circular flange clamp.

[0045] FIG. 10D is a cross sectional view of adjacent ends of dual wall corrugated plastic pipe sections having flanges formed from circumferential portions of end corrugations showing the preferred embodiment.

[0046] FIG. 10E is a cross sectional view of two end sections of dual wall corrugated plastic pipe, a wedged shaped gasket formed to match the internal surface of the end corrugations and a circular flange clamp before final assembly showing the preferred embodiment.

[0047] FIG. 10F is a cross sectional view of a section of an assembled soil tight and water tight joint composed of two flanged ends of dual corrugated plastic pipe, a wedged shaped gasket formed to match the internal surface of the end corrugations and circular flange clamp showing the preferred embodiment.

[0048] FIG. 10G is a cross sectional view of adjacent ends of dual wall corrugated plastic pipe sections having flanges formed from circumferential portions of end corrugations, wedged shaped gasket formed to match the internal surface of the end corrugations and bell and spigot flange clamp.

[0049] FIG. 10H is a cross sectional view of two end sections of dual wall corrugated plastic pipe, a wedged shaped gasket formed to match the internal surface of the end corrugations, bell and spigot flange clamp before final assembly.

[0050] FIG. 10I is a cross sectional view of a section of an assembled soil tight and water tight joint composed of two flanged ends of dual corrugated plastic pipe, a wedged shaped gasket formed to match the internal surface of the end corrugations and bell and spigot flange clamp.

[0051] FIG. 11A is cross sectional view of two end sections of single wall corrugated plastic pipe in which a flange is formed from a circumferential portion of the end corrugations.

[0052] FIG. 11B is a cross sectional view of two end sections of single wall corrugated plastic pipe, a flat gasket and a circular flange clamp before final assembly of a joint.

[0053] FIG. 11C is a cross sectional view of a section of an assembled soil tight and water tight joint composed of two flange ends of single wall corrugated plastic pipe, a flat gasket and a circular flange clamp.

[0054] FIG. 12A shows a cross sectional view of two end sections of adjacent dual wall corrugated plastic pipes in which a flange is formed from the liner at the pipe end.

[0055] FIG. 12B is a cross sectional view of sections of the ends of two dual wall corrugated plastic pipes with flanges formed from the liner at the pipe ends, a flat gasket and a circular flange clamp before final assembly of a joint.

[0056] FIG. 12C is a cross sectional view of a section of an assembled joint composed of two ends of adjacent dual wall corrugated plastic pipes having flanges formed from the liner of the pipes at the pipe ends, a flat gasket and a circular flange clamp.

[0057] FIG. 13A is cross sectional view of sections of two ends of dual wall corrugated plastic pipes having end flanges formed from a portion of the end corrugation and the liner at the pipe end.

[0058] FIG. 13B is a cross sectional view of sections of two ends of dual wall corrugated plastic pipes in which a flange is formed from a portion of the end corrugation and the liner at the pipe end, a flat gasket and a circular flange clamp before final assembly of a joint.

[0059] FIG. 13C is a cross sectional view of a section of an assembled joint composed of two ends of dual wall corrugated plastic pipe in which a flange is formed from a portion of an end corrugation and the liner at the pipe end, a flat gasket and a circular flange clamp.

[0060] FIG. 14A is cross sectional view of sections of two ends of dual wall corrugated plastic pipe having a flange formed from a circumferential portion of the end corrugations.

[0061] FIG. 14B is a cross sectional view of two sections of ends of dual wall corrugated plastic pipe, an “O” ring gasket and a circular flange clamp before final assembly of a joint.

[0062] FIG. 14C is a cross sectional view of a section of an assembled joint composed of two flange ends of dual wall corrugated plastic pipe, an “O” ring gasket and a circular flange clamp.

[0063] FIG. 15A is cross sectional view of sections of two ends of dual wall corrugated plastic pipe in which a flange is formed from a circumferential portion of the end corrugations of the respective pipes.

[0064] FIG. 15B is a cross sectional view of two sections of ends of dual wall corrugated plastic pipe, an external inverted “V” gasket and a circular flange clamp before final assembly of a joint.

[0065] FIG. 15C is a cross sectional view of a section of an assembled joint composed of two flange ends of dual wall corrugated plastic pipe, an external inverted “V” gasket and a circular flange clamp.

[0066] FIG. 16A is a cross sectional view of a dual wall corrugated plastic “Y” fabricated fitting with end flanges joined to sections of dual wall corrugated polyethylene pipe having corresponding end flanges.

[0067] FIGS. 16B and 16C respectively show the front and end views of an assembly of a molded stepped reducing “T” fitting joining two in-line pipe sections of dual wall corrugated plastic pipe to a smaller diameter dual wall corrugated plastic pipe.

[0068] FIGS. 16D and 16E respectively show the front and end views of an assembly of a fabricated “T” fitting joining two in-line pipe sections of dual wall corrugated plastic pipe to smaller diameter dual wall corrugated plastic pipe by means of a molded stepped reducer.

[0069] FIG. 17 shows a front view of a kit for providing a water tight seal including a gasket and a circular flange clamp for forming the joint and seal, and two pipe sections having end flanges with which the kit is used.

[0070] FIG. 18 shows a front view of a kit for providing a water tight seal between corrugated plastic pipe sections including a gasket, a circular flange clamp, a router, and a router guide for forming the flange at the end of the respective two pipe sections to be joined at their end flanges.

[0071] FIG. 19 shows a structural joint formed by pipe or fitting end flanges and clamp without a gasket between the facing flanges.

[0072] FIG. 20A is a side view of a joint applied to a non-circular, oblong, oval elliptical or other curvilinear perimeter pipe.

[0073] FIG. 20B is a radial cross section of the joint of FIG. 20A also showing a single sectioned toggle clamp.

BEST MODE FOR CARRYING OUT THE INVENTION

[0074] The invention facilitates the field installation of structural, soil tight and water tight joints between sections of single and multiple wall corrugated plastic pipe utilized for drainage and sanitary sewer applications. The invention provides a section of corrugated plastic pipe having a flange at its end formed from the circumferential portion of a corrugation segment and/or the pipe liner. In its different aspects and embodiments, the invention comprises a section of a plastic pipe, or fittings for plastic pipe, having transverse corrugations and an end flange maintained in a joint relationship by a peripheral clamp.

[0075] The invention produces joints between pipes and a pipe and fitting have tightness properties ranging from a structurally sound, tight joint effected by the use of a clamp only (without a gasket) with regard to a flanged end, ranging to soil tight, water tight and gas tight joints depending on flange, gasket and clamp design parameters to adapt the joint system for a predetermined use or environment. A circumferential portion of a corrugation or a circumferential portion of the liner extending from the corrugated pipe section forms the flange. In an assembly, two abutting sections of corrugated plastic pipe having flanges on their ends are joined together in an assembly in which a peripheral flange clamp engages the flanged ends forming a structural joint.

[0076] A gasket may be interposed between the flanges. The gasket may have a flat annular shape, a wedge shaped cross section, or an “O” ring shaped cross section and may include other shapes such as ridges and the like on the surface thereon. In the invention, a section of corrugated plastic pipe having a flange may be joined to any section of a complementary pipe or fitting having a flange. The circular flange clamp may be a “V” (or “U” shape) groove or channel single segment retaining coupling or a similarly shaped open retainer coupling having a multiplicity of sections circumferentially disposed to join the abutting flange end sections of the adjacent pipe sections.

[0077] The invention also comprises a method of forming a flange at the end of a pipe section or fitting having transverse corrugations in which the flange is formed from a circumferential portion of the end corrugation and/or the liner of the pipe at the end of the pipe section or fitting.

[0078] In providing a soil tight and/or water tight seal between pipe sections, the invention comprises a method of joining abutting sections of flanged pipe by providing a section of corrugated plastic pipe and a rigid plastic or metal pipe or fitting having a flange at its end, inserting a gasket between or around the two flanges, and circumferentially clamping the flanges to provide pressure on the exterior surface flanges to draw them together and thereby compress the gasket. A peripheral flange clamp having a single segment or a multiplicity of segments joins the flanged ends and provides compression of the gasket when a gasket is used. The method further involves forming a flange at the end of a section of corrugated plastic pipe by transversely severing a section of the corrugated pipe at an axial location of a pipe end corrugation.

[0079] The invention is also a kit for providing a water tight seal between adjacent sections of corrugated plastic pipe or a section of corrugated plastic pipe and a pipe or fitting having a flanged end. The kit comprises a gasket and a circular flange clamp having an initial opening sufficient to receive therein the adjacent flanges of the pipe sections to be joined; the clamp compresses the gasket between the flanges. For the on site fabrication of joints between corrugated pipe sections and another flanged component, the kit of the invention includes a portable router or saw and guide fixture assembly for making field cuts in a section of corrugated pipe and/or fabricated fittings. The router or saw provides a flange at the pipe or fitting end by cutting away a circumferential portion of a pipe corrugation or liner to form the flange from the remaining section of the corrugation.

[0080] FIG. 1 shows the preferred embodiment for two sections of dual wall corrugated plastic pipe 1 each having a flange 2 at its end formed from a circumferential portion of a corrugation. FIG. 2 shows the preferred embodiment for a single wall corrugated plastic pipe 3 at its end having a flange 2 formed from a circumferential portion of a corrugation. FIG. 3 shows another embodiment for sections of dual wall corrugated plastic pipe 1 having a flange 2 at its end formed from a circumferential portion of the liner 4. FIG. 4 shows a dual wall corrugated plastic pipe 1 having a flange 2 at its end formed from a circumferential portion of the liner 4 and a portion of a corrugation.

[0081] In the invention, a corrugated pipe with a design having a flange formed from a circumferential segment of the end corrugation, from the liner at the end of the pipe or from a circumferential segment of an end corrugation and the liner is provided. The method of fabricating flanged ends on plastic pipe with transverse corrugations can be accomplished in the factory and in the field by cutting the pipe at a corrugation so that a flange shaped portion of the end corrugation remains. In the field, the contractor can cut the corrugated pipe and form the flange simultaneously by using a portable router or other cutting devices such as a circular saw having a fixture that guides the cutter around the circumference of the pipe at the desired axial position. While the application herein refers to the pipe and joint elements as “circular,” it is noted that the large diameter pipes with which the invention is intended to be used may have other cross sections, such as elliptical, oval and the like and it is intended to include such cross sections as well within the scope of the term “circular.” FIGS. 20A and 20B illustrate such pipes and joints.

[0082] The invention also provides a design and method for water tight joining of plastic pipe having transverse corrugations. FIG. 5A shows a soil tight and water tight joint design for dual wall pipe having transverse corrugations. This joint comprises a section of dual wall plastic pipe 1 having transverse corrugations and a flange 2 formed from the circumferential section of the end corrugation, a wedged shaped gasket 16 inserted between to abutting flanges and a “V” retaining circular flange clamp 6. FIG. 5B shows a soil tight and water tight joint for two abutting dual wall corrugated plastic pipe sections having flange ends 2, an “O” ring gasket 7 between the abutting flanges and a single segment “V” retaining circular flange clamp 9. FIG. 5C shows a soil tight and water tight joint between a dual wall corrugated plastic pipe having a flange end and a rigid pipe 10 end also having a flange end. This embodiment demonstrates how metal and rigid plastic pipe ends 10 can be joined with a flat gasket 5 and a multi segmented “V” retaining circular flange clamp 9. FIG. 5D exhibits an embodiment that shows how the method and design shown in FIG. 5C can be applied to join corrugated plastic pipe to concrete pipe 11 by using a metal pipe section 12 that is fixed to the concrete pipe by mortar. FIG. 5E exhibits an embodiment in which two abutting dual wall corrugated pipe flange ends are joined by an “inverted wedge” circular flange clamp compressing an “O” ring gasket. FIG. 6A shows soil tight and water tight joining of two sections of dual wall corrugated plastic pipe 1. In this embodiment, circular flange clamp 14 has two split annular plates and an external reverse “V” gasket 13. FIG. 6B shows the soil tight and water tight joint embodiment wherein circular clamp 14 is utilized to compress the flat gasket 5. FIG. 7A and 7B show respectively a front and side view of an annular flat gasket 5 preferably fabricated from a cross-linked elastomer or rubber. FIG. 7C and 7D show respectively a front and side view of a wedge shaped gasket 16. Many shapes are suitable for this application; an example is the “O” ring 7 shown in FIGS. 7E and 7F . Some categories of gaskets, however, have rounded, elliptical, or other cross-sections that are intended herein to be included within the definition of “O” ring gaskets. FIGS. 7G and 7H respectfully shows a front and side view of an external gasket 13 having an inverted “V” cross-section. The external gasket straddles the outside of the flanges 2. FIG. 8A and 8B are front and sides views that show a typical circular flange clamp 6 sometimes referred to as a “V” retaining coupling. The function of this flange clamp 6 is to draw the flanges together as the diameter of the clamp is made smaller by the action of closing a clamp or a tightening a bolt 18. The “V” shaped circular channel 17 provides a dual wall tapered clamping action that compresses the gasket between the flanges. The material of construction of the “V” retaining coupling can include a rigid plastic or metal. The preferred embodiment utilizes a stainless steel similar to 301, 303 and 304 stainless steel to minimize corrosion, however, galvanized steel or rigid plastic construction is adequate and may be more cost effective than stainless steel. 316 stainless steel is utilized for marine applications where salt water is a concern. The “V,” “U,” inverted wedge or other open shaped groove, slot, or receptacle of the peripheral flange clamp may be formed from a single segment or multiple segments. Multi-segmented “V” retaining couplers provide more convenient assembly by making the circular flange clamp 9 more flexible. Preferably, the perimeter clamp should have sufficient hoop flexibility to accommodate the change in shape or roundness caused by back filling. The clamp should allow a resiliency comparable to that of the pipe to accommodate expansion and contraction, and compression of the pipe when it is buried. FIGS. 8C and 8D respectively show a front and side view of a “V” retaining circular flange clamp 9 with three segments. The tri-segmented circular flange clamp 9 is preferred to single, dual and quad segmented clamps; however, all are satisfactory. FIGS. 8E and 8F respectively show a front and side view of a tri-segmented, “inverted wedge” shaped circular flange clamp. FIGS. 9A and 9B respectively show front and side views of an alternate circular flange clamp 14 having two split annular plates that are brought axially together to compress the gasket.

[0083] There have been many attempts to utilize larger circular flange type clamps to draw the full end corrugations together and simultaneous compress a gasket. These attempts fail because of the flexibility of the corrugations. The corrugations readily deform under pressure and move out of the way when water pressure is applied. Efforts are being made to stiffen the corrugations by injecting them with rigid foam to improve the joint properties. The structural advantage of the present invention is that the circular flange clamp does not rely on the stiffness of the plastic. Instead the plastic is subjected to compression by the circular flange clamp and transfers this stress into the gasket. The stress-cracking behavior of the pipe is not significantly affected because there are little or no tensile stresses applied to the plastic flange.

[0084] FIGS. 8I and 8J show a ratchet style flange clamp 17. The advantage of ratchet type flange clamps are that they offer a convenient way of making a connection between the ends of the cylindrical band 18 initially and sub sequentially closing the gap between the ends of the cylindrical band 18. This clamp has two straps 65 that are attached to one end of the periphery of cylindrical band 18 and having radially inward projection on the other. A series of holes in the cylindrical band 18 provide a means of interlocking the inward radial projections on straps 65. The tightening of the clamp in this case is accomplished by and external lever mechanism 64 that increases the over lap of straps 65 and cylindrical band 18 causing the radial inward projection to ratchet tighter by interlocking with a hole further from the ends of cylindrical band 18. There are a multitude of ratchet mechanisms some that utilize external straps or wire, integral toggle mechanisms, some with radial outward and/or axial projections and others. The example shown in FIGS. 81 and 8J is intended to demonstrate that flange clamps having ratchet mechanisms represent embodiments to this disclosure.

EXAMPLE I

[0085] An example of the preferred embodiment is the forming of water tight joints with High Density Polyethylene (HDPE) pipe utilized for drainage and sanitary sewer applications. The circular flange clamp is a “V” retaining coupling fabricated from 301 Stainless Steel and the gasket is extruded and spliced from natural rubber, polyisobutylene or neoprene rubber. In this example, the corrugated HDPE pipe has corrugations that are too flexible to maintain the gasket compression required for water tight sealing. As a result, typically, the corrugations are filled with rigid foam to provide sufficient stiffness. The process of foaming the corrugations is time consuming and relatively expensive. The present invention eliminates stiffening requirements because the rigid clamp provides the stiffness. In this preferred embodiment the wedged shaped gasket may be a cured natural rubber or polyisobutylene having a durometer or hardness on the Shore A scale between 45 and 60. However, a variety of elastomeric gaskets having similar properties will also function well.

[0086] FIGS. 10A, 10B and 10C and FIGS. 10D, 10E and 10F show the construction of a soil tight and water tight joint between two sections of dual wall corrugated plastic pipe 1 with flange ends formed from a circumferential portion of the end corrugations. This joining is accomplished by inserting a wedge shaped gasket 16 and wedged shaped gasket 61 having a contour that matches the interior surface of flange 2 between abutting flange ends of the dual wall corrugated plastic pipe and squeezing the gasket with the circular flange clamp 6. In this preferred embodiment, the flange clamp and gasket is designed so that the gasket compresses between 5% and 30% when clamp is closed. The gasket compression may vary depending on the durometer of the gasket and the water tight pressure limit required. The preferred configuration utilizing 10% compression of a 45 Shore A durometer typically tests water tight as per ASTM 3212 to pressures that exceed 30 pounds per square inch. The pressure limit specified in ASTM 3212 is 10.8 psi. The minimal wetted area of the gasket minimizes the hydraulic effect that tends to separate the pipe under internal pressure and the rigidity of the flange clamp locks pipe ends together thereby preventing joint separation normally a result ground shifts, seismic anomalies and improper back fill. The invention also provides the capability of designing the flange clamp so that the clamp system provides a pressure relief function to protect the pipe from transient internal pressure surges that reach a predetermined level that requires relief. This is accomplished in pipes of predetermined size by reducing the stiffness of the radial walls of the clamp sufficiently to provide a leakage at a pre-selected internal pressure.

EXAMPLE II

[0087] In this second example, the method and design of soil-tight and water tight joining of single wall corrugated plastic pipe is demonstrated for a second time. FIG. 11A shows two sections of single wall corrugated plastic pipe 3 with a flange 2 formed by a circumferential portion of an end corrugation. FIG. 11B shows the components for fabricating a water tight joint; the single wall plastic pipe 3 with flange 2, the flat gasket 5 and the circular flange clamp 6 in the open position. FIG. 11C shows the assembled joint wherein the circular flange clamp 6 is closed causing the gasket 5 to compress. Flange 2 is in compression avoiding tensile stresses that enhance stress cracking.

EXAMPLE III

[0088] This example shows an alternate means of applying the disclosed invention to the water tight joining of dual wall corrugated plastic pipe. FIG. 12A shows two sections of dual wall plastic pipe 1 having transverse corrugations and flanges 2 at the pipe end formed from the liner. FIG. 12B shows the components for fabricating a water tight joint; the dual wall plastic pipe 1 with flange 2 formed from the liner 4, the flat gasket 5 and the circular flange clamp 6 in the open position. FIG. 12C shows the assembled joint wherein the circular flange clamp 9 is closed causing the gasket 5 to compress.

EXAMPLE IV

[0089] This fourth example demonstrates the method of applying the invention disclosure to dual wall corrugated plastic pipe 1 having a flange 2 at its end formed by both the liner 4 and the corrugation as shown in FIG. 13A. FIG. 13B shows the components for fabricating a soil tight and water tight joint; the dual wall plastic pipe 1 with flange 2, a wedge shaped gasket 7 and the circular flange clamp 9.

EXAMPLE V

[0090] The fifth example demonstrates in FIGS. 14A, 14B and 14C, the method of applying the invention disclosure to dual wall corrugated plastic pipe 1 having a flange end 2, an “O” ring gasket 7 and circular clamp 6.

EXAMPLE VI

[0091] The sixth example demonstrates in FIGS. 15A, 15B and 15C, the method of soil tight and water tight joining of sections of dual wall corrugated plastic pipe 1 by compressing an external gasket 13 that straddles the flange ends 2 and is compressed by circular flange clamp 6.

EXAMPLE VII

[0092] FIG. 16A represents an embodiment of this invention wherein dual wall corrugated plastic fabricated “Y” fitting are joined to sections of dual wall corrugated plastic pipe by inserting a gasket 5 between the end flanges and by utilizing circular flange clamps 9. Although this embodiment is portrayed by using a “Y” fitting, the invention can be applied equally well to most fittings including but not limited to “T”, 4 way, elbows and angle fittings.

EXAMPLE VIII

[0093] FIGS. 16B and 16C respectively show front and side views of an embodiment of this invention wherein a molded in-line reducing “T” fitting 37 fitting that couples two sections of dual wall corrugated plastic pipe 1 and an integral, stepped, off-set, selectable pipe size, reducer coupling 38 to a corrugated plastic pipe 41 having the same or smaller pipe size as the corrugated plastic pipe 1. All joints are comprised of a gasket between the end flanges that are sealed by circular flange clamps 9 as depicted in FIGS. 5A, 5B and 5C. This design is unique in the fact that it discloses an integral, off-set, selectable size, reducer coupling 38 for soil and water tight joining of dual wall corrugated plastic pipe. The integral reducer coupling comprises a series of flange diameters wherein the flange diameter of choice is selected by cutting the reducer coupling 38 at the plane that matches the size requirement. In this example the reducer coupling was cut at plane 30. A field cut at plane 31 and 32 offer larger diameter possibilities. Please note that the axes of the reduced fitting options are off set so that the drainage into and out of the pipe will always be at the bottom or top of the pipe. The integral selectable reducer coupling 38 need not be offset and the selectable reducing diameters could be concentric. This invention has the advantage that the pipe manufacturer need only produce one universal fitting wherein the customer can field select the reduced pipe size by simply cutting off the stepped reducer coupling at the desired flange diameter.

EXAMPLE IX

[0094] FIGS. 16D and 16E respectively show front and side views of an embodiment of this invention wherein a molded selectable diameter, stepped off-set reducer coupling 40 is utilized to join a fabricated in-line reducing “T” fitting to two corrugated plastic pipe sections 1 and a section of dual wall corrugated plastic pipe 41 having a flange diameter smaller than the connecting fitting. This is accomplished by inserting a gasket between the end flanges and by utilizing circular flange clamps 9 as indicated previous in FIGS. 5A, 5B and 5C. This design is unique in the fact that it discloses a design and method for joining standard fabricated fitting to corrugated flange end plastic pipe sections by means of a molded selectable size, off-set reducer coupling. The selectable size feature is achievable by cutting the reducer at the plane that matches the size requirement. In this example the reducer was cut at plane 35. A field cut at plane 36 offers a larger diameter possibility. Please note that the axes of the reduced fitting options are off set so that the drainage into and out of the pipe will always be at the bottom or top of the pipe. This invention has the advantage that the pipe manufacturer need only produce one size diameter for each fitting type and provide a molded selectable stepped offset reducer coupling that the customer can field cut to select the proper pipe size.

EXAMPLE X

[0095] FIGS. 10G, 10H and 10I show a bell and spigot embodiment of this invention. FIG. 10G shows dual wall corrugated plastic pipe 1, wedged shaped gasket having a contour that matches the internal surface of flanges 2 and flange clamp bell 62 and flange clamp spigot 63. FIG. 10H shows the joint partially assembled wherein the flange clamp bell 62 is expanded as it passes over flange clamp spigot 63. Flange clamp bell has axially slots cut into its outer circumferential protrusion (not shown in the FIG. 10G, 10H and 10I) that permit the bell to expand in a flat spring like manner. FIG. 10I show the fully assembled flange clamp bell and spigot joint whereby the flat spring fingers of flange clamp bell 62 contract inward to lock in place flange clamp spigot 63 and sustain compression of wedged shaped gasket 61. This embodiment although more complex and costly demonstrates how the invention provides the axial compression of the gasket and rigidity of the coupling and still can be assembled in the manner similar to the bell and spigot joints using radial compressed gaskets.

[0096] A kit shown in FIG. 17 is used in the field to provide a joint between adjacent sections of corrugated plastic pipe 1 or a section of corrugated plastic pipe having essentially similar cross-sections and a pipe or fitting having a flanged end. The kit includes a gasket 5 having a cross-sectional shape in a correspondence with the sections to be joined and a circular flange clamp having a cross sectional shape such that the clamp 9 is capable of straddling the flanges at the end sections to be joined. FIG. 18 shows a kit that includes a portable router, saw, or other suitable cutting device 20 and guide fixture 21 for making field cuts in the end section of the corrugated pipe to provide a flange at the end thereof by forming a radially extending circumferential portion of a section of a corrugation or the liner of the corrugated pipe.

INDUSTRIAL APPLICABILITY

[0097] The manner in which the invention is capable of exploitation in industry and the way in which the invention can be made and used are evident from the foregoing description and the nature of the invention. A new and improved corrugated polyethylene pipe, and a joint and joining method, system, and kit therefor is provided that is useful in drainage, agriculture, highway, sanitary sewer, waste water reuse, irrigation, industrial waste, animal waste and fiber optics, utility cable, and other pipe based applications.

[0098] Having thus described the invention in detail, those skilled in the art will appreciate that, given the present disclosure; modifications may be made to the invention without departing from the spirit of the inventive concept herein described. Rather, it is intended that the scope of the invention be determined by the appended claims.

Claims

1. A section of a large diameter corrugated plastic pipe having transverse corrugations and a flange formed by a circumferential portion of a corrugation radially extending from the end section of the pipe.

2. A section of a large diameter corrugated plastic pipe having transverse corrugations and an inner liner in which a flange is formed by a circumferential portion of the corrugation radially extending from the end section of the pipe.

3. A section of a large diameter corrugated plastic pipe having transverse corrugations and an inner liner in which a flange is formed by a portion of the liner radially extending from the end section of the pipe.

4. A section of a large diameter corrugated plastic pipe having transverse corrugations and an inner liner in which a flange is formed by a circumferential portion of the corrugation in substantial contact with a portion of the liner radially extending from an end section of the pipe.

5. Two abutting sections of large diameter corrugated plastic pipe each having transverse corrugations and a flange intrinsically formed from the pipe material at abutting ends joined in an assembly having a clamp encompassing the abutting flanges and forming a joint.

6. Two sections of large diameter corrugated plastic pipe each having transverse corrugations and a flange intrinsically formed from the pipe material at the end of each pipe section joined in an assembly in which a gasket is interposed between the flanged ends of the pipe and a peripheral clamp encompasses the abutting flanges.

7. The pipe sections of claim 6 in which the gasket has a flat surface in a correspondence with the surface of the flange transverse to the axis of the pipe facing from the end of a pipe.

8. The pipe sections of claim 6 in which the gasket has an essentially trapezoid shaped transverse cross section corresponding to the adjacent transverse cross sections of the abutting pipe flanges at the joint.

9. The pipe section of claim 7 in which the gasket includes a wedge shaped section.

10. The pipe section of claim 7 or 8 or 9 in which corners of the gasket are contoured.

11. The pipe section of claim 6 in which the gasket comprises an “O” ring shape in transverse cross section.

12. The assembly of claim 5 or claim 6 in which the peripheral clamp includes an internal channel facing toward the center of the pipes and straddles the flanges to provide a compressive force.

13. The assembly of claim 5 or claim 6 in which the peripheral clamp includes facing sections at the opposite sides of the flanges on the pipes to be joined and the clamp provides a compressive force between the flange surfaces in the longitudinal direction of the pipe axis.

14. The assembly of claim 12 in which the clamp comprises one of an inverted “V” channel and an inverted “U” channel extending around a section of the flange.

15. The assembly of claim 12 in which the clamp encompasses the flanges and comprises a wedge shape in transverse cross section having an opening at one end and an extended section at the opposite end in which the open section of the wedge is lesser in length than the extended section and faces the center of the pipe with respect to the longitudinal axis of the pipe.

16. The assembly of claim 12 in which the clamp comprises a multiplicity of peripheral sections joined circumferentially about the flange.

17. The assembly of claim 12 in which the clamp extends peripherally about the flanges in a single circumferential length essentially in correspondence with the nominal diameter of the pipes joined.

18. A section of large diameter corrugated plastic pipe having transverse corrugations and a flange at an end intrinsically formed from the pipe material joined to one of the group of plastic pipes; non-plastic pipes; plastic fittings; and non-plastic fittings having a flange end at the location of a joint.

19. The method of providing a flange at the end of a corrugated plastic pipe section having transverse corrugations by cutting off a circumferential portion of an end corrugation to provide a remaining section of the corrugation integrally and radially extending from the end of the pipe as a flange.

20. The method of providing a flange at the end of a dual wall corrugated plastic pipe section having transverse corrugations and a liner by cutting off a circumferential portion of an end corrugation and the liner to provide a remaining section of the corrugation integrally and radially extending from the end of the pipe as a flange.

21. The method of claim 19 or claim 20 for forming a flange at the end of a corrugated plastic pipe section having transverse corrugations and a liner including forming a circumferential flange portion integrally and radially extending from the end of the pipe from the liner.

22. The method of joining a section of corrugated pipe plastic having a flange at its end forming a first member abutting a second member being a section of a corrugated pipe, a non-plastic pipe or a fitting having a flange at its end comprising aligning the first and second members in a co-linear relationship in which the end flanges of the members are in an approximately abutting relationship, and applying a clamp circumferentially straddling the flanges to provide an axially compressive force on the exterior surface of the flanges to draw the flanges together.

23. The method of claim 22 including inserting a gasket between the flanges and compressing the gasket with the force generated by tightening the applied clamp.

24. Two sections of large diameter corrugated plastic pipe each having transverse corrugations and a flange at the end of each pipe section joined in a clamped assembly in which a channel clamp is applied to the radially peripheral ends of the flanges and the clamp exerts a force to compress the gasket between the inner surface of clamp channel and the outer peripheral edges of the flanges.

25. A kit for providing a joint between adjacent sections of corrugated plastic pipe or a section of corrugated plastic pipe having essentially similar cross-sections and a pipe or fitting having a flanged end, the kit including a peripheral flange clamp having a cross sectional shape such that the clamp is capable of straddling the flanges at the end sections to be joined.

26. The kit of claim 25 including a gasket having a cross-sectional shape in a correspondence with the flanges at the sections to be joined.

27. The kit of claim 25 including a portable cutting device and a guide fixture for making field cuts in the end section of a corrugated pipe to provide a flange at an end of the pipe by cutting off a circumferential portion of an end corrugation to provide a remaining section of the corrugation integrally and radially extending from the end of the pipe as a flange.

28. The method of forming a flange at the end of a section of corrugated plastic pipe by transversely severing from the pipe a section of a corrugation of the pipe at an axial location on the corrugation at the end of a pipe section.

29. The method of forming a flange at the end of a section of a dual wall corrugated plastic pipe by transversely severing from the end section of the pipe a section of a corrugation and a section of the liner.

30. A fitting having at least two flanges in which one of the fitting ends has an off set, selectable diameter flange reducer coupling capable of being cut off at a predetermined flange diameter.

31. The fitting of claim 30 wherein the fitting comprises a molded plastic composition.

32. The fitting of claim 31 wherein the fitting is one of an in-line, “Y”, “T”, 4 way, elbow or angle.

33. The assembly of claim 5 or claim 6 in which the clamp is one of a toggle clamp, a ratchet clamp and a screw clamp.

34. The assembly of claim 6 in which the clamp comprises an interlocking assembly of mating components seated within the recess of a corrugation at each pipe end and straddling the flanges, the components interlocking upon the exertion of an axial force upon the pipe sections in the longitudinal direction of the pipe and compressing the gasket interposed between the flanges.

35. The assembly of claim 6 providing a predetermined pressure relief in which the stiffness the radial walls of the clamp is predetermined at a sufficiently low measure to provide a leakage at the joint at a pre-selected internal pressure.