Corrugated plastic pipe sections having flanged ends and structurally tight joints thereof
Rigid corrugated plastic pipe sections are provided with a flange radially extending from at least one end of the pipe length, which allows structural and water tight joints between connecting flanged pipes and fittings to be formed in an assembly including a peripheral clamp and gasket, and a system, method and kit for effecting structural and water tight joints in corrugated plastic pipe pipes.
This application is a continuation of application Ser. No. 10/698,601 filed Oct. 31, 2003, which in turn is a continuation of Ser. No. 09/893,846, filed on Jun. 28, 2001
BACKGROUND OF THE INVENTIONLarge diameter corrugated plastic (typically formed from polyethylene) pipe sections 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 obtain a reliable water tight joint.
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 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.
BRIEF SUMMARY OF THE INVENTIONThe 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.
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.
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.
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.
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.
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 THE SEVERAL VIEWS OF THE DRAWINGS
The invention facilitates the field installation of structural, soil tight and water tight joints between sections of 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.
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.
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.
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.
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.
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.
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.”
The invention also provides a design and method for water tight joining of plastic pipe having transverse corrugations.
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.
EXAMPLE IAn 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 50 and 60. However, a variety of elastomeric gaskets having similar properties will also function well.
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.
This example shows an alternate means of applying the disclosed invention to the water tight joining of dual wall corrugated plastic pipe.
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
The fifth example demonstrates in
The sixth example demonstrates in
A kit shown in
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 peripheral flange clamp for clamping a circumferential flange of a corrugated plastic pipe to a circumferential flange of a second plastic corrugated pipe or fitting, comprising:
- a clamp body having a first sidewall and a second sidewall;
- an interior channel formed by said first sidewall and said second sidewall and configured to provide and inside clearance between an inside radius of said body and an outer circumference of said flanges;
- a clamping mechanism configured to cause said first and second sidewalls to engage respective ones of said circumferential flanges; and
- wherein said first and second sidewalls are configured to draw said circumferential flanges axially together upon engagement therewith.
2. The flange clamp according to claim 1, wherein said first and second sidewalls are configured to not radially extend to valleys of the corrugations in the pipes immediately adjacent to the flanges.
3. The flange clamp according to claim 1, wherein said flange clamp has a resiliency comparable to that of the plastic corrugated pipe.
4. The flange clamp according to claim 1, wherein said channel forms a V-shaped channel.
5. The flange clamp according to claim 1, wherein said channel forms an U-shaped channel.
6. The flange clamp according to claim 1, wherein said channel forms an inverted wedge-shaped channel.
7. The flange clamp according to claim 6, wherein said inverted wedge channel encompasses an external, reverse “V” gasket.
8. The flange clamp according to claim 1, wherein said clamping mechanism causes the diameter of said clamp body to decrease.
9. The flange clamp according to claim 8, wherein said body comprises a plurality of peripheral sections.
10. The flange clamp according to claim 9, wherein said plurality of peripheral sections are movably connected to one another such that said sections may move radially outward or inward to encompass said flanges.
11. A peripheral flange clamp for clamping a circumferential flange of a corrugated plastic pipe to a circumferential flange of a second plastic corrugated pipe or fitting, comprising:
- a clamp body having a V-shaped interior channel and configured to engage said circumferential flanges and cause said flanges to draw axially together; and
- a clamping device configured to cause said channel to engage said circumferential flanges.
12. The flange clamp according to claim 11, wherein said V-shaped channel is formed by a first side wall and a second sidewall, said first and second sidewalls configured to engage said flanges to cause said flanges to draw axially together.
13. The flange clamp according to claim 11, wherein said clamp body is comprised of a plurality of segments movably connected to one another such that said clamp body may move radially to increase or decrease its diameter to encompass and tighten around the flanges.
14. The flange clamp according to claim 11, wherein said interior channel is configured to provide an inside clearance between an inside radius of said body and an outer circumference of said flanges.
15. The flange clamp according to claim 11, wherein said clamp body is configured to encompass said circumferential flanges that have an end portion that does not substantially extend along or parallel to a longitudinal axis of said flanges.
16. A peripheral flange clamp for clamping a circumferential flange of a corrugated plastic pipe to a circumferential flange of a second plastic corrugated pipe or fitting, comprising:
- a clamp body having an inverted wedge-shape interior channel and configured to engage said circumferential flanges and cause said flanges to draw axially together; and
- a clamping device configured to cause said channel to engage said circumferential flanges.
17. The flange clamp according to claim 16, wherein said channel is formed by an outside wall connecting to an angled first sidewall and an angled second sidewall, said first and second sidewalls configured to engage said flanges to cause said flanges to draw axially together.
18. The flange clamp according to claim 16, wherein said body comprises a plurality of peripheral segments.
19. A peripheral flange clamp for clamping a circumferential flange of a corrugated plastic pipe to a circumferential flange of a second plastic corrugated pipe or fitting, comprising:
- a clamp body having a first sidewall and a second sidewall, said first and second sidewalls configured to form an interior channel and to encompass said circumferential flanges that have an end portion that does not substantially extend along or parallel to a longitudinal axis of said flanges;
- a clamping device configured to cause said first and second sidewalls to engage respective ones of said circumferential flanges; and
- wherein said first and second sidewalls are configured to draw said circumferential flanges axially together upon engagement therewith.
20. The flange clamp according to claim 20, wherein clamping device draws said flanges axially together such that said flanges compress a gasket positioned between said flanges.
Type: Application
Filed: Mar 30, 2005
Publication Date: Aug 4, 2005
Inventor: Joseph Starita (Marysville, OH)
Application Number: 11/093,594