U.S. patent application number 11/061639 was filed with the patent office on 2006-08-24 for piping system with transition coupling.
This patent application is currently assigned to Environ Products, Inc.. Invention is credited to Michael C. Webb.
Application Number | 20060188337 11/061639 |
Document ID | / |
Family ID | 36912874 |
Filed Date | 2006-08-24 |
United States Patent
Application |
20060188337 |
Kind Code |
A1 |
Webb; Michael C. |
August 24, 2006 |
PIPING SYSTEM WITH TRANSITION COUPLING
Abstract
In a pipeline system having a plurality of pipe segments joining
a fluid supply tank to a fluid dispenser, the invention includes a
pipe coupling assembly for use on at least one terminal end of a
fluid transfer pipe, where the transfer pipe has an inner tubular
member for transferring fluid and an outer tubular member and an
interstitial space there between. The coupling assembly comprises a
transition coupling for attachment to the pipe segment to provide a
first path for the fluid in the inner tubular member and a second
path for the interstitial space. The coupling assembly further
comprises a transition tube assembly for attachment to the
transition coupling to provide separate paths for the transfer
fluid and the interstitial space, where the interstitial space
provides a means for performing leak detection or fitting integrity
tests during application of either a vacuum condition or
pressurized gas input via such selective access.
Inventors: |
Webb; Michael C.; (Raleigh,
NC) |
Correspondence
Address: |
DRINKER BIDDLE & REATH;ATTN: INTELLECTUAL PROPERTY GROUP
ONE LOGAN SQUARE
18TH AND CHERRY STREETS
PHILADELPHIA
PA
19103-6996
US
|
Assignee: |
Environ Products, Inc.
|
Family ID: |
36912874 |
Appl. No.: |
11/061639 |
Filed: |
February 22, 2005 |
Current U.S.
Class: |
405/52 ;
137/236.1; 405/154.1 |
Current CPC
Class: |
F16L 2201/30 20130101;
B67D 7/78 20130101; B67D 1/00 20130101; Y10T 137/4807 20150401;
F16L 39/00 20130101; B67D 7/3209 20130101; F16L 11/20 20130101;
Y10T 137/402 20150401 |
Class at
Publication: |
405/052 ;
405/154.1; 137/236.1 |
International
Class: |
E02B 13/00 20060101
E02B013/00; B63B 35/03 20060101 B63B035/03 |
Claims
1. A pipe system for distributing fluids from a storage tank to one
or more dispensers comprising: an originating adaptor fitting
located at the tank and shear valves located at each of the one or
more dispensers; a pipe segment extending between the adaptor
fitting and one of the shear valves, said pipe segment having an
interstitial space between an inner and an outer pipe; a transition
coupling connecting the adaptor fitting to the pipe segment, said
transition coupling comprising a ferrule, an insert, a means for
securing the coupling to the adaptor fitting; said transition
coupling further comprising sealing means for preventing fluid
leakage from the coupling connection to the fitting, said coupling
further comprising sealing means for preventing fluid leakage from
the interstitial space between the inner and outer pipes, and
further comprising an interstitial access port for connecting a
tube that provides access to the interstitial space between the
inner and outer pipes.
2. The piping system of claim 1, wherein the sealing means for
preventing leakage from the coupling connection to the fitting and
the sealing means for preventing leakage from the interstitial
space of the pipe are O-rings.
3. The piping system of claim 1, wherein the sealing means for
preventing leakage from the coupling connection to the fitting is a
butt seal compressed between the coupling insert and the adaptor
fitting.
4. The piping system of claim 1, wherein the means for securing the
transition coupling to the fitting include a threaded end on the
adaptor fitting and a swivel locking nut on the coupling.
5. The piping system of claim 1, further comprising a tube assembly
for attachment to the transition coupling interstitial access port
for testing and monitoring the interstitial space of the piping
system.
6. A pipe system for distributing fluids from a storage tank to one
or more dispensers comprising: a plurality of dispenser sumps, each
housing a shear valve having inlet and outlet ports for
respectively receiving and transmitting fluid in a piping system, a
double-walled pipe having an interstitial space between an inner
pipe and an outer pipe, said pipe comprising an inlet pipe segment
and an outlet pipe segment for connection to each shear valve port,
each pipe segment joined to the respective inlet and outlet ports
of the shear valve by a transition coupling, said transition
coupling comprising; a ferrule, an insert, a means for securing the
coupling to the adaptor fitting; said transition coupling further
comprising sealing means for preventing fluid leakage from the
coupling connection to the fitting, said coupling further
comprising sealing means for preventing fluid leakage from the
interstitial space between the inner and outer pipes, and further
comprising an interstitial access port for connecting a tube that
provides access to the interstitial space between the inner and
outer pipes.
7. The piping system of claim 6, wherein the sealing means for
preventing leakage from the coupling connection to the shear valve
and the sealing means for preventing leakage from the interstitial
space of the pipe are O-rings.
8. The piping system of claim 6, wherein the sealing means for
preventing leakage from the coupling connection to the shear valve
is a butt seal compressed between the coupling insert and the shear
valve port.
9. The piping system of claim 6, wherein the means for securing the
transition coupling to the fitting include a threaded end on the
adaptor fitting and a swivel locking nut on the coupling.
10. The piping system of claim 6, wherein a tube is connected from
the interstitial access port of the transition coupling at the
shear valve inlet port to the transition coupling of the shear
valve outlet port, said tube providing a continuous path around the
shear valve for the interstitial space of the double-wall pipe.
11. The piping system of claim 6, further comprising a tube
assembly for attachment to the transition coupling interstitial
access port for testing and monitoring the interstitial space of
one or more pipe segments.
12. The piping system of claim 6 wherein said interstitial access
port is connected with a test tube for continuous monitoring of the
integrity of the double-wall pipe system interstitial space.
13. A piping system of double-wall pipe having an interstitial
space between an inner and an outer pipe comprising: one or more
pipe sections each pipe section connecting to one or more fittings
selected from the group consisting of adaptor fittings, shear
valves, and terminating elbow fittings, wherein the connections
between each fitting and pipe section is made with a transition
coupling comprising a ferrule, an insert, a means for securing the
coupling to the fitting; said transition coupling further
comprising sealing means for preventing fluid leakage from the
transition coupling connection to the fitting, said coupling
further comprising sealing means for preventing fluid leakage from
the interstitial space between the inner and outer pipes, and
further comprising an interstitial access port for connecting a
tube that provides access to the interstitial space between the
inner and outer pipes.
14. The piping system of claim 13, wherein the sealing means for
preventing leakage from the coupling connection to the fitting is a
butt seal compressed between the coupling insert and the
fitting.
15. The piping system of claim 13, wherein the means for securing
the transition coupling to the fitting includes a threaded end on
the fitting and a swivel locking nut on the coupling.
16. The piping system of claim 13, wherein the ferrule and insert
are a single-piece construction.
17. The piping system of claim 16, wherein said single-piece
ferrule and insert comprises: a dual cylindrical portion having an
outer cylinder and an inner cylinder, wherein the outer cylinder is
the ferrule and the inner cylinder is an insert into the
double-wall pipe; the outer cylinder comprising barbs on its inner
surface for engagement with the outer pipe of the double-wall pipe,
the inner cylinder comprising barbs on its outer surface for
engagement with the inner pipe of the double-wall pipe.
18. The piping system of claim 13, further comprising a tube
assembly for attachment to the transition coupling interstitial
access port for testing and monitoring the interstitial space of
one or more pipe segments.
19. The piping system of claim 13 wherein said interstitial access
port is connected with a test tube for continuous monitoring of the
integrity of the double-wall pipe system interstitial space.
Description
FIELD OF THE INVENTION
[0001] This invention relates to transition coupling and fitting
assemblies for connecting segment of pipes into systems. More
particularly, the invention relates to a new system using an
assembly for coupling coaxial pipes, such as flexible coaxial
pipes, of the type used in environmentally conscious petroleum
transfer systems.
BACKGROUND OF THE INVENTION
[0002] Because vehicle fueling facilities, like retail service
stations, are becoming more environmentally conscious, a shift has
occurred from the use of rigid underground piping to flexible
piping. A primary reason for this shift from rigid to flexible
piping is that flexible piping has fewer pipe connections than
rigid systems since the flexible system can accommodate virtually
any orientation or alignment of the pumps and tanks. With fewer
pipe connections, the piping system is considered more
environmentally safe. Movement of the underground storage tank due
to the shifting underground tanks is also more easily accommodated
by flexible piping.
[0003] Flexible underground piping systems have also gained
popularity because these systems are more easily installed than
rigid piping systems. Rigid systems require on-site measurements
and cutting of each piece, along with the intensive labor involved
in making two pipe connections every time the piping undergoes a
change in direction. Flexible underground piping systems thus can
be installed at a lower total cost than conventional rigid piping
systems.
[0004] As part of the development of underground piping systems, it
has been necessary to provide a means of secondary containment for
both the primary piping and for the associated fittings in order to
provide a margin of safety in case of leaks or damage to the
system. The secondary containment pipe protects the primary supply
pipe from the ambient environment and from inadvertent damage, and
further, provides for a method of containing the fluid from the
primary pipe in the event of a rupture or leak of the primary
pipe.
[0005] Several types of double wall flexible piping systems are
known. These include systems which have a small flexible pipe
housed in a larger flexible containment pipe. One such system is
described in U.S. Pat. No. 4,971,477 (the '477 patent), wherein
access chambers are separated by a secondary containment pipe which
is sized to accept a primary pipe within the secondary containment
pipe. This system, however, has a number of drawbacks, including
the fact that the primary and secondary pipes are installed
separately and that fittings are required for each of the two types
of pipes. Moreover, because each of the pipes connects with an
access chamber, a rapid and simple method of monitoring the
condition of the primary piping may not be possible. Although the
sumps in the '477 patent are capable of being monitored visually by
an attendant, but the demand of other tasks to be performed by the
attendant eventually leads to fewer and fewer inspections. Most
important is that leaks may occur randomly, not only just prior to
a visual inspection, and especially when inspections grow less
frequent over time.
[0006] As taught in the '477 patent, the flexible piping and the
secondary containment piping require a sump or access chamber each
time that sections of the flexible pipe are joined together. Most
other systems also require a sump at each location where sections
of flexible pipe are joined together.
[0007] Other systems which have met with success using coaxial
pipes and a secondary containment pipe are shown in U.S. Pat. Nos.
5,263,794 (the '794 patent), and 5,297,896 (the '896 patent) the
entire disclosures of which are incorporated herein by reference.
The advantages of flexible pipe systems are disclosed by these
patents. Nevertheless, it is necessary to make individual
connections each time sections of pipes are joined together.
[0008] The '794 and the '896 patents disclose various definitions
that have become standard in the industry, for example, "tanks",
"pumps", "dispensers" and the like. Also disclosed therein are
descriptions of double wall piping systems that provide secondary
containment. In a system that employs secondary containment, a
primary pipe carries the petroleum product or other hazardous
material from the underground tank to the aboveground dispenser.
The primary pipe, also known as the supply pipe, is located inside
a larger, outer secondary containment pipe, known also as the
containment pipe. Access sumps and other containment components are
located around the tank pump, underneath the dispenser and at
various junctions of piping.
[0009] Recently, an effective system has become available and has
met with substantial success in the industry. This pipe system's
supply pipe is a flexible double wall pipe comprising an inner pipe
and an outer pipe in radial communication with the outside surface
of the inner pipe. Most preferred are pipes of this configuration
that have internally facing longitudinal ribs on the inner surface
of the outer pipe, or externally facing longitudinal ribs on the
outer surface of the inner pipe. In either such design, a plurality
of circumferentially spaced ribs extend radially from one pipe
member to the other pipe member such that the ribs have a surface
that confronts and snugly engages the other pipe to define an
interstitial space between the two pipes.
[0010] The flexible double wall pipe described immediately above is
disclosed in my U.S. patent 5,527,130 entitled Environmentally Safe
Underground Piping System, the entire disclosure of which is
incorporated herein by reference. The co-axial pipes disclosed in
the '130 patent are normally suited for use with hazardous material
transfer pipe systems of the type described herein. The inner most
layer is formed from a material such as nylon, PVDF, polyethylene
or the like, which is highly resistant to the hazardous transfer
fluid. The outer jacket of the double wall pipe which is exposed to
the ambient underground environment is formed from a material such
as nylon, PVDF, polyethylene or the like, which is highly resistant
to the ambient underground environment and which does not degrade
over time. Between the outer wall of the primary pipe and the inner
wall of the containment pipe is an intermediate layer, either in
the form of ribs projecting from one surface to the other, or in a
standoff layer formed from a cylindrical portion having
circumferentially spaced ribs that define the interstitial space
between the two pipes. As noted in the '130 patent, other layers
can be present in the design, such as intermediate layers formed
from lower cost materials which do not directly contact either the
hazardous material being transported or the ambient underground
environment.
[0011] The environment for both surfaces of the pipe is an
important design aspect, which needs to be considered. Product
components which make up primary or secondary containment systems
for hazardous liquids, and in underground applications
particularly, must be designed, manufactured and individually
tested to insure that they will not fail due to material
deterioration.
[0012] The material employed are preferably resistant to
hydrolysis, as it is expected that water and high moisture
conditions will exist in underground burial applications both for
contained and non-contained underground piping applications.
Resistance to hydrolysis is important since some elastomers suffer
an irreversible breakdown when exposed for lengthy periods to hot
water, moisture vapor or tropical climates.
[0013] In addition to the tanks, pumps, pipes and dispensers used
in underground piping systems, sumps are used as part of the
secondary containment system. One sump surrounds the pump on the
tank and another sump is generally positioned below each dispensing
system. Sumps typically have a base portion, a riser and a lid and
are provided with means for permitting piping to enter and exit the
sump. One type of sump called a tank sump is located on top
underground storage tank and under a surface access manhole.
Contained within the tank sump is a dispensing pump whereby the
fuel is directed upwardly from the tank to the dispensing pump and
outwardly through the opposite side of the tank sump to the next
part of the system. Each time the pipe sections are connected to
one another, these pipe connections are typically contained within
another sump that, of course, requires a pipe penetration seal to
seal the pipe entry or exit through the sump.
[0014] As can readily be appreciated, every pipe must eventually
end. It then becomes necessary to connect that end of the pipe to
either a pump, to a fitting joining two or more other pipes or
directly to a shear valve. Typically the inner, primary supply pipe
is directly connected to fittings and the like, and another primary
supply pipe is connected to the other end or ends of the fittings.
Merely connecting the inner supply pipes, as in the past, has been
no different than connecting a single pipe system. In the evolution
of piping systems as discussed above, the relationship of the
outer, secondary containment pipe to the system has become more
complex.
[0015] Initially, non-flexible pipes functioning as a secondary
containment pipe were attached to the sump or other chambers by
enlarging the hole in the sump to permit entry or exit of the outer
pipe from the sump, and later by various fastening and sealing
methods and devices. Initially, the interstitial space between the
inner and outer pipes served as a conduit for fluid leakage to flow
downhill into the next sump in the piping system. Leaks could come
from fuel from the inner pipe, or from the outer pipe as ambient
environmental liquids, such as water, penetrate the outer pipe.
[0016] Leak detection initially consisted of opening the sump
chamber and inspecting the bottom of the sump for fluid
accumulation. Of course, whatever can be visually inspected can be
monitored automatically. Systems were proposed for monitoring the
liquid levels in the bottom of sumps. However, every sump had to
have a monitoring device since each sump, by design, represented a
low point where fluid could collect. The difficulty in such two
pipe systems can easily be seen by viewing FIG. 2 of '477 patent
where the outer pipe has a very limited, minor function of simply
isolating the primary supply pipe from the ambient environment.
Also shown in that Figure is the way that the interstitial space
between the primary pipe and containment pipe merely opened into
the larger sumps without any recognition that there may be other
purposes for the interstitial space. As is shown in FIG. 3 of the
'477 patent, the secondary containment pipe merely serves as a
housing or conduit for sections of the primary supply pipe which
may be inserted or removed as desired.
[0017] In my U.S. Pat. 5,398,976, I disclosed a connecting boot
that substantially improves utilization of the interstitial space.
The connecting boot, commonly known as a "test boot", comprises a
device which fits onto one terminal end of a supply pipe, allowing
the inner primary supply pipe to extend out from the connecting
boot while the outer secondary containment pipe terminates inside
the connecting boot. The exit end of the test boot where the
primary supply pipe exits is clamped to, or otherwise sealingly
engages, the outer surface of the primary pipe. The entrance end of
the test boot that fits over the exterior of the secondary
containment pipe is also clamped to, or is sealingly engaged with,
the outer pipe surface. In between these two sealed ends of the
test boot is a chamber, which communicates with the interstitial
spaces of the two pipes and also communicates with a radially
extending port. An elbow fitting and tube is usually provided which
can be connected to the radially extending port and elbow fitting
on the adjacent pipe, to which the primary pipe has been attached
in a conventional manner.
[0018] Thus, for the first time, it was possible to connect not
only the interstitial spaces of two adjacent pipes but also the
interstitial spaces of an entire system, which are connected to a
single monitoring device. Such a monitoring device could be a
system whereby the entire interstitial space of all of the piping
is filled with a liquid to a level, which registers in a
predetermined range of the monitoring device to indicate a securely
contained system. When the level of the fluid in the interstitial
space either drops below a certain amount or rises above a certain
amount, indicating a change in the system, an alarm will sound.
[0019] The test boot provided a substantial advance in the
hazardous fluid piping system industry, primarily by permitting
interconnection of all of the system wide interstitial spaces. The
test boot, however, is not as structurally solid as an access sump,
for example, and thus needs to be enclosed in a sump for
protection.
[0020] There are several additional considerations that need to be
addressed in designing the connections between sections of pipes,
particularly between sections of flexible coaxial pipes. First, it
is desirable to avoid plastic adhesion or plastic thermally bonded
connections, since temperature conditions, chemical exposure,
vibrations over time can cause piping joints to fail. A much better
seal is achieved when metal and plastic are joined together by
mechanical means. However, in such cases it is necessary to protect
the metal from the environment by a coating or isolation to avoid a
corrosive and unsafe condition. Coatings on metal parts, however,
often peel off or become damaged during handling of the metal
parts. Also, if the coatings are too thick, the necessary metal to
plastic contact to establish an effective seal is not achieved.
[0021] As will be apparent from reviewing the above patents, there
is an interstitial space between the inner primary supply pipe and
the outer secondary containment pipe. This interstitial space has
been used to transfer leaked fluid into the containment sump or
access chamber. Typically, in early systems, the access chambers
were inspected on a regular basis to see if quantities of fluid had
collected. This, of course, does not provide a rapid response to a
major leak of fluid such as fuel from the primary supply pipe.
[0022] As shown in the '794 and the '876 patents, the entire system
is connected such that the primary pipe functions as a closed
system, transporting fuel from the supply tank to the various
dispensers. However, the interstitial space between the primary
supply pipe and the secondary containment pipe is a conduit
allowing leaked fluid to flow to an access chamber for observation.
Although it is possible to monitor the conditions of one or all of
the access chambers, for example by visual inspection, no simple
method of monitoring the entire system is possible.
[0023] It is desirable to provide an underground piping system
which employs coaxial pipe, such as those pipes described above,
which include a inner primary supply pipe and a outer secondary
containment pipe, in which the interstitial space between the two
pipes can be connected to the interstitial spaces in other segments
of piping to form a continuous closed system of interstitial
space.
[0024] It is also desirable to provide a coupling assembly for use
with coaxial pipes that permits coupling of the interstitial space
between the coaxial pipes with corresponding interstitial spaces in
other segments of pipe.
[0025] Such a system should also provide an effective monitoring
system utilizing the interconnected interstitial space of the
coupling assembly, particularly with the use of a constant vacuum
or pressure applied to the interstitial space or monitoring the
liquid level of a liquid filled interstice.
SUMMARY OF THE INVENTION
[0026] The invention is a pipe system for distributing fluids from
a storage tank to one or more dispensers comprising an originating
adaptor fitting located at the tank and shear valves located at
each of the one or more dispensers, a pipe segment extending
between the adaptor fitting and one of the shear valves, the pipe
segment having an interstitial space between an inner and an outer
pipe. The invention further comprises a transition coupling
connecting the adaptor fitting to the pipe segment, the transition
coupling comprising a ferrule, an insert, a means for securing the
coupling to the adaptor fitting, the transition coupling further
comprising sealing means for preventing fluid leakage from the
coupling connection to the fitting, the coupling further comprising
sealing means for preventing fluid leakage from the interstitial
space between the inner and outer pipes, and further comprising an
interstitial access port for connecting a tube that provides access
to the interstitial space between the inner and outer pipes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] These and other aspects of the present invention of the
various details of the operation and construction thereof are
hereinafter more fully set forth with reference to the accompanying
drawings, wherein:
[0028] FIG. 1 is a schematic illustration of one embodiment
underground piping system.
[0029] FIG. 2 is a schematic illustration of a second embodiment of
underground piping system.
[0030] FIG. 3 is a side, elevational view of a originating adapter
fitting connected with a transition pipe coupling.
[0031] FIG. 4 is a side, elevational view of a junction tee fitting
connected with two transition pipe couplings.
[0032] FIG. 5 is a side, elevational view of a terminating elbow
fitting connected with a transition pipe coupling.
[0033] FIG. 6 is a side, elevational view of a junction Y shear
valve connected with two transition pipe couplings.
[0034] FIG. 7 is a side, elevational view of a terminating shear
valve connected with two transition pipe couplings.
[0035] FIG. 8 is an end sectional view of double wall coaxial pipe
section.
[0036] FIG. 9 is an end sectional view of double wall coaxial pipe
section fitted with a transition pipe coupling.
[0037] FIG. 10 is a side sectional view of various components that
make up o-ring seal transition coupling.
[0038] FIG. 11 is a side, elevational view of various components
that make up an o-ring seal transition coupling.
[0039] FIG. 12 is a side, sectional view of various components that
make up o-ring seal transition coupling.
[0040] FIG. 13 is a side, elevational view of various components
that make up butt seal transition coupling.
[0041] FIG. 14 is a side, sectional view of various components that
make up butt seal transition coupling.
[0042] FIG. 15 is a side, elevational view of various components
that make up transition coupling with a butt compression seal
connection.
[0043] FIG: 16 is a side, sectional view of various components that
make up butt seal transition coupling.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0044] Referring now to the drawings and particularly to FIG. 1 and
2 thereof, there is shown schematically an underground piping
system for conveying petroleum products from an underground storage
tank to a plurality of aboveground dispensers. The piping system
incorporates a novel coupling means in accordance with the present
invention. The pipe transition coupling of the present invention is
particularly adapted for interconnecting the interstitial regions
in the piping to provide a closed, continuous monitoring system for
detecting leaks that provides advantages over prior art piping
systems used for this purpose.
[0045] As best illustrated in FIG. 1, the basic elements of a
underground fuel storage and delivery system include an underground
storage tank 1 for containing a large quantity of a petroleum
product. The storage tank 1 is equipped with tank sump 3 for
secondary containment of the dispensing pump 2 that is connected to
the top of the storage tank 1 and located under a manhole cover 6
to provide surface 32 access to the tank sump 3. A plumbing
assembly 4, is connected on one end to the dispensing pump 2 and on
the other end is fitted with an originating adapter fitting 70 for
connection of a transition coupling 40 fitted to the end of a pipe
segment 10. The pipe segment 10 exits the sidewall 4 of the tank
sump 3 through a sump penetration seal 25 that prevents liquids
from entering or exiting the tank sump 3 though the penetration.
Also illustrated in FIG. 2 is a sealed attachment of a chase pipe 9
that is used for the future removal and replacement of a damaged
pipe section 10 without the need for excavation.
[0046] Also shown in both FIGS. 1 and 2 is a monitoring system 7
that is connected to the transition coupling 40 by the test tube 49
to monitor the integrity of the interstitial space of the pipe
system. The monitoring system 7 provides early warning of leaks in
the underground piping system and thereby to minimize chances of
contaminating the underground environment. The monitoring system 7
monitors a change in positive pressure or negative pressure or
liquid level within the interstitial space of a double-walled pipe
depending upon the type of monitoring system installed. Where there
is no monitoring system 7 installed, the test tube 49 would
typically be left open at its end for any piping leaks to flow in
the tank sump for detection either visual inspection or a sump leak
detection monitor.
[0047] Referring to FIG. 1, a double wall pipe segment exits the
tank sump 3 and then enters the sidewall 21 of a junction dispenser
sump 20a, mounted under an above ground dispenser 30. Contained
within the deep junction dispenser sump 20a is a riser pipe
assembly that typically includes a rigid or flexible riser pipe 73,
a standard shear valve 74 and a junction tee fitting 71. The
standard shear valve 74 makes connection with the above ground
dispenser 30. Pipe segment 10a enters the sidewall 21 of the deep
junction dispenser sump 20a and makes connection with the junction
tee fitting 71 by means of the transition coupling 40 fitted to its
end. Another pipe segment 10b, which is connected to the other side
of the junction tee fitting 71, exits the sidewall 21 of the deep
junction sump 20a. The pipe entry and exit penetrations in the
sidewall 21 are sealed by the pipe penetration seals 22.
[0048] The next piping segment 10b exits the first junction
dispenser sump 20a and then enters the sidewall 21 of the
terminating dispenser sump 20b where the piping system terminates.
Contained within a deep terminating dispenser sump 20b mounted
under an above ground dispenser 30, is a riser pipe assembly that
typically includes a rigid or flexible riser pipe 73, a standard
shear valve 74 and a terminating elbow fitting 72. The standard
shear valve 74 makes connection with the above ground dispenser 30.
A pipe segment 10c enters the sidewall 21 of the deep terminating
dispenser sump 20b and makes connection with the terminating elbow
fitting 72 by means of the transition coupling 40 fitted to its
end. The pipe entry penetrations in the sidewall 21 are sealed by
the pipe penetration seal 22.
[0049] FIG. 2 has the same basic elements as FIG. 1 with exceptions
that the deep dispenser sumps have been substituted with shallow
dispenser sumps. Contained within a shallow junction dispenser sump
120a mounted under an above ground dispenser 30, is junction Y
shear valve 75 that makes connection with the above ground
dispenser 30. A pipe segment 10a enters the angled sidewall 21 of
the shallow junction dispenser sump 20a and makes connection with
the junction Y shear valve 75 by means of the transition coupling
40 fitted to its end. Another pipe segment 10b, which is connected
to the other side of the junction Y, shear valve 75, exits the
angled sidewall 21 of the shallow junction sump 120a. The pipe
entry and exit penetrations in the sidewall 21 are sealed by the
pipe penetration seals 22.
[0050] The next piping segment 10b exits the first shallow junction
dispenser sump 120a and then enters the angled sidewall 21 of the
shallow terminating dispenser sump 120b where the piping system 9
terminates. Contained within a shallow terminating dispenser sump
120b mounted under an above ground dispenser 30, is terminating
elbow shear valve 76 that makes connection with the above ground
dispenser 30. A pipe segment 10b enters the angled sidewall 21 of
the shallow terminating dispenser sump 120b and makes connection
with the terminating elbow shear valve 75 by means of the
transition coupling 40 fitted to its end.
[0051] FIG. 3 is close up view of the plumbing connection between
the originating adapter fitting 70 connected to a transition
coupling 40 fitted on the end of a pipe section. 10. Also shown are
the tube fittings 50 fitted on each end of the test tube 49 which
is connected to the interstitial port 47 of the transition fitting
40 by means of the tube fitting 50.
[0052] FIG. 4 is close up view of the plumbing connection between
the junction tee fitting 71 connected to two pipe sections 10 each
fitted with a transition fitting 40. Also shown are the tube
fittings 50 fitted on each end of a connector tube 48 which is
connected to the interstitial port 47 of each transition fitting 40
by means of the tube fitting 50 to continue the interstitial space
from one pipe section 10 to the other.
[0053] FIG. 5 is close up view of the plumbing connection between
the terminating elbow fitting 72 connected to a transition coupling
40 fitted on the end of a pipe section 10. Also shown are the tube
fittings 50 fitted on each end of the test tube 49 which is
connected to the interstitial port 47 of the transition fitting 40
by means of the tube fitting 50.
[0054] FIG. 6 is close up view of the plumbing connection between
the junction shear valves 75 connected to two pipe sections 10 each
fitted with a transition fitting 40. Also shown are the tube
fittings 50 fitted on each end of a connector tube 48 which is
connected to the interstitial port 47 of each transition fitting 40
by means of the tube fitting 50 to continue the interstitial space
from one pipe section 10 to the other.
[0055] FIG. 7 is close up view of the plumbing connection between
the terminating elbow shear valves 76 connected to a transition
coupling 40 fitted on the end of a pipe section 10. Also shown are
the tube fittings 50 fitted on each end of the test tube 49 which
is connected to the interstitial port 47 of the transition fitting
40 by means of the tube fitting 50.
[0056] FIG. 8 shows an end section view of the pipe segments 10
which are preferably co-axial pipes of the type shown and described
in my U.S. Pat. 5,527,130 entitled Environmentally Safe Underground
Piping System, and commercially available from Environ Products,
Inc., Smithfield, NC (USA) under the trademark GEOFLEX. Pipe
segments 10 comprise an inner primary pipe 12 made of a
non-degradable or inert material, such as nylon, PVDF and
polyethylene, with respect to the petroleum products being handled
in the piping system and an outer containment pipe 14 made of a
non-degradable or inert material, such as nylon, PVDF and
polyethylene when exposed to the ambient environment and thus is
suitable for direct burial applications.
[0057] The co-axial pipe also has a series of circumferentially
spaced longitudinally extending standoff ribs 15 defining a series
of longitudinal interstitial spaces 13 or passageways extending
from end to end in the pipe segments 10.
[0058] The coupling assemblies, called "transition couplings" of
the present invention have a double wall design and provide for
transition of interstitial spaces in ways that have previously not
been possible. Sealing the inner primary pipe is accomplished by a
mechanically locked barb seals and radial o-ring seals or flat butt
type compression seals. The coupling portion of the present
invention effectively seals the inner pipe and the outer pipe
simultaneously.
[0059] The transition coupling assembly includes a ferrule
preferable made of metal, attached to the outer wall of the pipe
segment at the coupling end. The ferrule has an annular ring
extending from the coupling end of the pipe segment in the axial
direction of flow having a series of internal barbs for a sealed
and secure engagement of the outer wall of the outer pipe of the
pipe segment. The ferrule also has a small threaded interstitial
access port for attachment of various tube assemblies that will
redirect the path of the interstitial space.
[0060] A second component of the transition coupling assembly is an
insert, preferably made of metal, which is attached to the inner
wall of the pipe segment at its coupling end. The insert, which is
expanded into the inner pipe wall, includes an inner annular ring
extending from the coupling end of the pipe segment in the
direction of fluid flow. An exterior portion of the insert has a
series of external barbs for a sealed and secure engagement of the
inner wall of the inner pipe of the pipe segment.
[0061] In a different type of transition coupling assembly design,
the ferrule and insert would be of a one piece construction instead
of the two piece construction as described above.
[0062] A third component of the transition coupling assembly is an
internally threaded swivel nut that is loosely attached to the
insert or ferrule/insert in such a manner that it can freely
rotate. A preferred means of attaching the swivel nut is to
internally expand a portion of the insert to lock on the swivel
nut.
[0063] A fourth component of the transition coupling assembly is an
externally threaded port of a single wall pipe fitting or shear
valve, which can be attached to the swivel nut. The externally
threaded connection port of the fitting or shear valve allows the
swivel nut to draw the coupling insert to or into the port opening
for making a sealed connection.
[0064] There are two types of sealed connections that are described
can be made between the coupling insert and connection ports of the
fittings or shear valves. The first is a radially sealed o-ring
connection. In this application there are two elastomeric o-rings
mounted externally to the sealing surface of the coupling insert.
Tightening of the swivel nut draws the male insert into the
connection port of the fitting or shear valve where the o-rings
seal the outer wall of the insert to the sealing surface of the
inner wall of the connection port.
[0065] The second application is a butt compression seal
application. In this application there is a flat ring seal,
typically made of a fluoroelastomeric material. Tightening of the
swivel nut draws the end face of the connection port towards the
flat ring seal in such a manner that it is compressed between the
radial end of the insert and the radial end of the connection port
making an effective seal.
[0066] The transition coupling further includes an o-ring seal that
seals the inside of the ferrule to the outside of the insert. The
purpose of this o-ring seal is to create a closed interstice that
prevents leaks in the joint located at the end of the ferrule
adjacent to the swivel nut. By sealing this joint between the
ferrule and insert the interstice can be directed to an
interstitial access port extending through the wall of the
ferrule.
[0067] Having an interstitial access port that is internally
threaded provides for the connection of tube assemblies that be
used for connection of the interstice of one pipe section to
another or may be used for periodic testing of one or more pipe
sections.
[0068] The integrity of the system is tested by applying pressure
or vacuum to the interconnected interstitial spaces of the pipe
segments, which have been formed into a closed system. If the
pressure or vacuum does not hold over a reasonable period of time,
the system likely has one or more fluid leaks. The fittings and
other components can then be inspected to locate leaks. Moreover,
after the entire system has been operating, the interstitial space
may again be subjected to pressure or vacuum to test for leaks. If,
for example, a vacuum is lost sooner than a predetermined period of
time or takes more than a predetermined time to achieve a given
vacuum, this will indicate that a leak is present. Also, a liquid
detector in the vacuum system would alert the user to a leak.
[0069] It is also possible in accordance with the invention to
continuously monitor the interstitial space. One such method is to
fill interstitial space of the closed system with a test fluid.
This test fluid is then monitored, either visually or
automatically, so that a sudden or gradual change in the amount of
test fluid in the interstitial space indicates that the system has
failed and that a leak exists. For example, if the inner tubular
member were damaged, substantial increase in fluid in the
interstitial space would occur, causing the fluid level in the
monitoring device to rise. Similarly, if the outer tubular member
were damaged, the test fluid would leak into the ambient
environment and the fluid level in the monitoring device would drop
indicating a break in the system. In all cases, controls are
provided to override any pumps in operation at the time to shut
down the system.
[0070] Another method would be to apply a constant positive or
negative pressure (vacuum) to the closed interstice of a piping
system having one or more piping segments. The pressure would be
continuously monitored by an electronic monitoring device that will
alarm if there is any significant change in pressure.
[0071] FIG. 9 shows a sectional end view of a coaxial pipe segment
10, fitted with a transition coupling 40 taken along line A-A in
FIG. 10. Pipe segment 10 comprises an inner primary pipe 12 and an
outer containment pipe 14. The coaxial pipe also has a series of
circumferentially spaced longitudinally extending standoff ribs 15
defining a series of longitudinal interstitial spaces 13 or
passageways extending from end to end in the pipe segments 10. The
end of the pipe segment 10 is fitted with a transition coupling 40
which is partially shown in this illustration to comprise an outer
metal ferrule 43. The ferrule has a series of internal annular
barbs 62 that engage and secure the outside of the outer pipe 14. A
metal insert 44 having external annular barbs 62 engages and
secures the inside of the inner pipe 12 when internally expanded
with a internal expansion coupling machine. The internal expansion
of the metal insert 44 compresses and secures both the inner pipe
12 and the outer pipe 14 in such a manner that it would take a
significant force (approx. 3,000 lbs.) to pull the penetration
coupling off of the end of the pipe segment 10. The compression
caused by the internal expansion is not sufficient to close off the
interstitial space 14 created by the standoff ribs 15 on the inside
of the outer pipe 14. The threaded interstitial port 47 of the
transition coupling 40 is shown to be situated forward of the end
of the pipe segment 10 in such a manner that it is in fluid
communication with the interstitial space 13 of the pipe segment
10. The interstitial port 47 can be either plugged or connected to
a tube fitting 50 of a connector tube 48 or test tube 49.
[0072] FIG. 10 is a cross-sectional view of end of a double wall
pipe segment 10 fitted with o-ring seal type transition coupling
40. The double wall pipe segment 10 has an outer pipe 14 having
standoff ribs 15 (FIG. 9) formed on its inside wall to create an
interstitial space 13 between the inner 12 and outer pipe 14. The
end of the pipe segment 10 is compressed between the inside of a
metal ferrule 43 and the outside surface of the metal insert 44.
The inside surface of the metal ferrule 43 has a series of barbs 62
that engage and secure the outside of the outer pipe 14. The
outside surface of the metal insert 44 has a series of barbs 62
that engage and secure the inside of the inner pipe 12.
[0073] The front inside end metal ferrule 43 has an o-ring seal 53
that seals the joint between the inside of the ferrule 43 and the
outside wall of the insert 44. The sealing of this joint allows a
closed interstice to be directed through threaded interstitial port
47 located near the front-end wall of the ferrule 43.
[0074] A locating rib 63 separates the end of the front end of the
ferrule 43 and the swivel nut 46 that is entrapped inside of the
locking groove 54 so that it will not come off. The swivel nut 46
has internal female connection threads 61 to mechanical engage the
connection port 60 of a fitting or shear valve.
[0075] A threaded swivel nut 46 is loosely secured to the insert 44
by means of an internal expansion process that locks it into the
locking groove 54. The swivel nut 46 is used to mechanically draw
the insert sealing surface 58 that is fitted with two o-ring seals
52 into the connection port 60 of the fitting or shear valve.
Within the connection port 60 the two o-ring seals 52 fitted on
insert sealing surface 58, engage the port sealing surface 59 to
form a liquid tight seal.
[0076] FIG. 11 illustrates components of an o-ring seal transition
coupling that makes a sealed connection to the inside of connection
port 57 of a fitting or shear valve. Shown are the end of the pipe
segment 10, the metal ferrule 43 and its interstitial port 47. The
metal insert 44 is shown to have external barbs 62 on its back end
and two o-ring seals 52 installed on the insert sealing surface 58
on the front end. A swivel nut 46 is loosely secured to the insert
44 by means of an internal expansion process that locks it into the
locking groove 54. The swivel nut 46 has internal connection
threads (not shown) that engage the external connection threads 61
located on the end section of the connection port 60. The swivel
nut 46 is used to mechanically draw the insert sealing surface 58
that is fitted with the two o-ring seals 52 into the connection
port 60 of the fitting or shear valve. Within the connection port
60 the o-ring seals 58 fitted on insert sealing surface 58, engage
the inside wall (59 in FIG. 10) of the connection port 60 to form a
liquid tight seal. Also illustrated is a connector tube 48 or test
tube 49, fitted with a tube fitting 50.
[0077] FIG. 12 is a cross-sectional view of the coupling assembly
illustrated in FIG. 11 and described in detail under FIG. 10
descriptions.
[0078] FIG. 13 illustrates components of a butt seal transition
coupling that makes a sealed connection to the face of connection
port 60 of a fitting or shear valve. Shown are the end of the pipe
segment 10, the metal ferrule 43 and its interstitial port 47. The
metal insert 44 is shown to have external barbs 62 on its back end
and a butt type insert sealing surface 58 on the front end. A
swivel nut 46 is loosely secured to the insert 44 by means of an
internal expansion process that locks it into the locking groove
54. The swivel nut 46 has internal connection threads 61 (not
shown) that engage the external connection threads 61 located on
the end section of the connection port 60. The swivel nut 46 is
used to mechanically draw the insert sealing surface 58, which is
fitted with a butt seal 52 to the port sealing surface 59 located
on the end of the connection port 60 of the fitting or shear valve.
By tightening the swivel nut 46 the butt seal 52 is compressed
between the insert sealing surface 58 and the port sealing surface
59 to form a liquid tight seal. Also illustrated is a connector
tube 48 or test tube 49, fitted with a tube fitting 50.
[0079] FIG. 14 is a cross-sectional view of end of a double wall
pipe segment 10 fitted with butt seal type transition coupling. The
double wall pipe segment 10 has an outer pipe 14 having standoff
ribs formed on its inside wall to create an interstitial space 13
between the inner pipe 12 and under pipe 14. The end of the pipe
segment 10 is compressed between the inside of a metal ferrule 43
and the outside of the backend of the metal insert 44. The inside
surface of the metal ferrule 43 has a series of barbs 62 that
engage and secure the outside of the outer pipe 14. The outside of
the metal insert 44 has a series of barbs 62 that engage and secure
the inside of the inner pipe 12.
[0080] The front inside end of the metal ferrule 43 has an o-ring
seal 53 that seals the joint between the inside of the ferrule 43
and the outside wall of the insert 44. The sealing of this joint
allows a closed interstice to be directed through threaded
interstitial port 47 located near the front end-wall of the ferrule
43.
[0081] A locating rib 63 separates the end of the front end of the
ferrule 43 and the swivel nut 46 that is entrapped inside of the
locking groove 54 so that it will not come off. The swivel nut 46
has internal female connection threads 61a to mechanical engage the
connection port 60 of a fitting or shear valve.
[0082] A threaded swivel nut 46 is loosely secured to the insert 44
by means of an internal expansion process that locks it into the
locking groove 54. The swivel nut 46 has internal connection
threads 61a that engage the external connection threads 61b located
on the end section of the connection port 60. The swivel nut 46 is
used to mechanically draw the insert sealing surface 58, which is
fitted with a butt seal 52 to the port sealing surface 59 located
on the end of the connection port 60 of the fitting or shear valve.
By tightening the swivel nut 46 the butt seal 52 is compressed
between the insert sealing surface 58 and the port sealing surface
59 to form a liquid tight seal.
[0083] FIG. 15 illustrates components of a butt seal transition
coupling that makes a sealed connection to the face of connection
port 57 of a fitting or shear valve. This particular type
transition coupling is like that described under FIG. 13 with the
exception that this coupling has ferrule and insert that is of a
one-piece construction. Illustrated are the end of the pipe segment
10, the one-piece ferrule/insert 45 and its interstitial port 47.
The one-piece ferrule/insert 45 is shown to be a butt type insert
sealing surface 58 on the front end. A swivel nut 46 is loosely
secured to the insert 44 by means of an internal expansion process
that locks it into the locking groove 54. The swivel nut 46 has
internal connection threads (not shown) that engage the external
connection threads 61 located on the end section of the connection
port 60. The swivel nut 46 is used to mechanically draw the insert
sealing surface 58, which is fitted with a butt seal 52 to the port
sealing surface 59 located on the end of the connection port 60 of
the fitting or shear valve. By tightening the swivel nut 46 the
butt seal 52 is compressed between the insert sealing surface 58
and the port sealing surface 59 to form a liquid tight seal. Also
illustrated is a connector tube 48 or test tube 49, fitted with a
tube fitting 50.
[0084] FIG. 16 is a cross-sectional view of end of a double wall
pipe segment 10 fitted with butt seal type transition coupling like
that described under FIG. 13 with the exception that this coupling
has ferrule and insert 45 that is of a one-piece construction.
Illustrated are the double wall pipe segment 10 that has an outer
pipe 14 having standoff ribs formed on its inside wall to create an
interstitial space 13 between the inner pipe 12. The end of the
pipe segment 10 is compressed within the interior walls of the one
piece ferrule/insert that has a series of barbs 62 on each interior
wall to engage and secure the end of the pipe section 10 when
compressed. A ferrule/insert 45 of one-piece construction has no
backend joint thus no o-ring seal is necessary to cause the closed
interstice to be directed through threaded interstitial port 47
located near the front end-wall of the ferrule 43.
[0085] The locating rib 63 separates the end of the front end of
the ferrule 45 and the swivel nut 46 that is entrapped inside of
the locking groove 54 so that it will not come off. The swivel nut
46 has internal female connection threads 61 to mechanical engage
the connection port 60 of a fitting or shear valve.
[0086] The threaded swivel nut 46 is loosely secured to the insert
44 by means of an internal expansion process that locks it into the
locking groove 54. The swivel nut 46 is used to mechanically draw
the insert sealing surface 58, which is fitted with a butt seal 52
to the port sealing surface 59 located on the end of the connection
port 60 of the fitting or shear valve. By tightening the swivel nut
46 the butt seal 52 is compressed between the insert sealing
surface 58 and the port sealing surface 59 to form a liquid tight
seal.
[0087] One advantage of the present invention is that that the
transition coupling permits the interstitial space of the entire
piping system to be interconnected into one closed system. Thus,
the interconnected interstitial space can be subjected to
pressurized air, preferably, pressurized nitrogen, to test the
entire system at one time. Moreover, liquid or gas interstitial
monitoring is readily obtained using the present invention. A
beneficial advantage of the present invention is that couplings,
fittings and connectors are non-elastomeric and not degradable so
the interstice may be pressurized to a much higher level if
required.
[0088] The transition coupling will not degrade after long-term
exposure to fuel, water, microbes, ozone or UV. Installation of
this transition coupling is much faster and more efficient than
systems that incorporate rubber test boots. Additionally, the
transition coupling assembly, system and method are capable of
withstanding stress from movement of the system as tanks are filled
and emptied and as water tables affect the components of the
system.
[0089] Even though particular embodiments of the present invention
have been illustrated and described herein, the description and
drawings are not intended to limit the invention and changes and
modifications may be made therein within the scope of the following
claims.
* * * * *