U.S. patent application number 10/482569 was filed with the patent office on 2004-10-21 for corrugated plastic pipe sections having flanged ends and structurally tight joints thereof.
Invention is credited to Starita, Joseph M.
Application Number | 20040207201 10/482569 |
Document ID | / |
Family ID | 25402203 |
Filed Date | 2004-10-21 |
United States Patent
Application |
20040207201 |
Kind Code |
A1 |
Starita, Joseph M |
October 21, 2004 |
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.
Inventors: |
Starita, Joseph M;
(Marysville, OH) |
Correspondence
Address: |
Edwin M Baranowski
Porter Wright Morris & Arthur
41 South High Street
Columbus
OH
43215
US
|
Family ID: |
25402203 |
Appl. No.: |
10/482569 |
Filed: |
December 29, 2003 |
PCT Filed: |
June 19, 2002 |
PCT NO: |
PCT/US02/19439 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10482569 |
Dec 29, 2003 |
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09893846 |
Jun 28, 2001 |
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09893846 |
Jun 28, 2001 |
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09597338 |
Jun 19, 2000 |
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09893846 |
Jun 28, 2001 |
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09788913 |
Feb 19, 2001 |
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09893846 |
Jun 28, 2001 |
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09794638 |
Feb 27, 2001 |
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Current U.S.
Class: |
285/363 ;
285/903 |
Current CPC
Class: |
F16L 23/036 20130101;
F16L 23/08 20130101; F16L 9/18 20130101; F16L 23/06 20130101; F16L
25/0045 20130101; F16L 9/06 20130101; F16L 21/03 20130101; Y10S
285/903 20130101; F16L 25/0054 20130101; F16L 25/0063 20130101 |
Class at
Publication: |
285/363 ;
285/903 |
International
Class: |
F16L 023/00 |
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.
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 .about.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.
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