U.S. patent application number 09/754824 was filed with the patent office on 2002-07-04 for pipe sealing apparatus.
Invention is credited to Lundman, Philip L..
Application Number | 20020083988 09/754824 |
Document ID | / |
Family ID | 25036508 |
Filed Date | 2002-07-04 |
United States Patent
Application |
20020083988 |
Kind Code |
A1 |
Lundman, Philip L. |
July 4, 2002 |
PIPE SEALING APPARATUS
Abstract
A pipe sealing apparatus insertable inside a pipe and inflatable
therein to prevent fluid flow and backflow through a defined
section of pipe. The pipe sealing apparatus has a first inflatable
plug at a first end and a second inflatable plug at a second end
connected by an elongated flexible tensile member and a fluid
pressure hose. Each inflatable plug has a plurality of ports that
may be connected to a source of fluid pressure, plugged, or left
unplugged depending on the application. The second inflatable plug
may be inflated either simultaneous with the first plug, or
independent of the first plug. Each inflatable plug also has a
flow-through conduit.
Inventors: |
Lundman, Philip L.;
(Fredonia, WI) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH, LLP
100 E WISCONSIN AVENUE
MILWAUKEE
WI
53202
US
|
Family ID: |
25036508 |
Appl. No.: |
09/754824 |
Filed: |
January 4, 2001 |
Current U.S.
Class: |
138/91 ;
138/93 |
Current CPC
Class: |
F16L 55/134
20130101 |
Class at
Publication: |
138/91 ;
138/93 |
International
Class: |
F16L 055/12 |
Claims
1. An inflatable plug assembly for plugging a pipe to restrict the
flow of fluid through the pipe, the inflatable plug assembly
comprising: a first inflatable plug; and a second inflatable plug
connected to the first inflatable plug in spaced apart relation by
an elongated flexible tensile member and by a fluid pressure
hose.
2. An apparatus as claimed in claim 1, wherein the first inflatable
plug includes: an inflatable middle section with a first end and a
second end; a leading pipe section supporting said first end of
said inflatable middle section; a trailing pipe section supporting
said second end of said inflatable middle section; a first fluid
port that extends through the wall of said leading pipe and is in
fluid communication with said inflatable middle section; a second
fluid port that extends through the wall of said leading pipe; a
third fluid port that extends through the wall of said trailing
pipe; a fluid conduit housed at least partially within said leading
pipe section and said trailing pipe section and extending between
said second fluid port and said third fluid port.
3. An apparatus as claimed in claim 2, wherein the first inflatable
plug further includes: a fourth fluid port that extends through the
wall of said leading pipe section and is in fluid communication
with said inflatable plug; a second fluid conduit that connects to
said first fluid port and is continuous to said fourth fluid port;
a fifth fluid port that extends through the wall of said trailing
pipe section and is in fluid communication with the inflatable
plug; a sixth fluid port that extends through the wall of said
trailing pipe section; and a third fluid conduit that connects to
said fifth fluid port and is continuous to said sixth fluid
port.
4. An apparatus as claimed in claim 2, wherein the first inflation
conduit is formed of: a first pressure hose fitting at the interior
end of said leading pipe section; a first tensile conduit
continuous from said second fluid port to said first pressure hose
fitting; a second pressure hose fitting at the interior end of said
trailing pipe section; a flexible conduit that connects said first
pressure hose fitting to said second pressure hose fitting; a
second tensile conduit that is continuous from said second pressure
hose fitting to said third fluid port.
5. An apparatus as claimed in claim 2, wherein the first inflatable
plug further includes: a flexible conduit that run through said
inflatable plug and connects said leading pipe section to said
trailing pipe section to allow for flow-through capabilities.
6. An apparatus as claimed in claim 2, wherein the fluid ports are
threaded bore or inlet fitted with a compression fitting assembly
onto which a high pressure flexible conduit may be connected.
7. An apparatus as claimed in claim 2, wherein the distal end of
said leading pipe section is threaded for selective attachment of a
hose or a threaded nipple.
8. An apparatus as claimed in claim 2, wherein the distal end of
said trailing pipe section is threaded for selective attachment of
a hose or a threaded nipple.
9. An apparatus as claimed in claim 1, wherein the second
inflatable plug includes: a second inflatable middle section with a
first end and a second end; a leading pipe section supporting said
first end of said inflatable middle section; a trailing pipe
section supporting said second end of said inflatable middle
section; a seventh fluid port that extends through the wall of said
leading pipe and is in fluid communication with said inflatable
plug.
10. An apparatus as claimed in claim 1, wherein the elongated
flexible tensile member is formed by a chain.
11. An apparatus as claimed in claim 1, wherein the fluid pressure
hose is continuous from said sixth fluid port to said seventh fluid
port for common inflation of said first inflatable plug and said
second inflatable plug.
12. An apparatus as claimed in claim 1, wherein the fluid pressure
hose is continuous from said third fluid port to said seventh fluid
port for independent inflation of said second inflatable plug.
13. A method for sealing a section of pipe, the method comprising
the acts of: providing a first inflatable plug; providing a second
inflatable plug connected to the first plug in spaced apart
relation by an elongated flexible tensile member and by a fluid
pressure hose; inserting the plugs into the section of pipe through
an opening in the pipe; positioning the plugs in spaced apart
relation in the pipe so as to define a length of pipe volume
between the plugs; and inflating the spaced apart plugs.
14. A method as set forth in claim 13, and further including the
step of forcing fluid into the space between the inflated spaced
apart plugs.
15. A method as set forth in claim 14, wherein the step of forcing
fluid into the space between the inflated spaced apart plugs
includes: measuring the pressure of the isolated area.
16. A method as set forth in claim 14, wherein the step of forcing
fluid into the space between the inflated spaced apart plugs
includes: forcing fluid through a pipe extending through one of the
plugs.
17. A method as set forth in claim 13, and further including the
step of positioning a hose in the defined section of pipe and
connecting the hose to a pump to remove fluid from the space
between the spaced apart plugs.
18. A method as set forth in claim 13, wherein the step of
positioning a hose in the defined section of pipe and connecting
the hose to a pump to remove fluid from the space between the
spaced apart plugs includes: running the hose through a pipe
extending through one of the plugs.
19. A method as set forth in claim 13, wherein the step of
inflating the plugs includes: forcing fluid through a first fluid
part into one of the plugs to inflate said one of said plugs; and
forcing fluid through a conduit extending through said first one of
said plugs and connected to the other of said plugs to inflate said
other of said plugs.
20. A method as set forth in claim 13, wherein the step of
inflating the plugs includes: forcing fluid through a fluid conduit
that connects a first fluid part in said one of the plugs to a
second fluid part in said second of said plugs to inflate said
plugs.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a pipe sealing apparatus that is
insertable in pipelines of varying diameters and inflatable therein
to seal a section of pipeline. Such a pipe sealing apparatus is
commonly referred to as an inflatable plug assembly.
BACKGROUND OF THE INVENTION
[0002] Inflatable plugs provide a useful means to mitigate the
uncontrolled release of fluids from a pipeline when a break occurs
in the pipeline and can also be used to isolate sections of
pipeline when performing repair or maintenance on the pipeline.
[0003] One prior art inflatable plug is described in U.S. Pat. No.
5,901,752 which is assigned to the assignee of the present
invention. The inflatable plug described there includes a first
support member disposed at a first end and a second support member
disposed at a second end. The inflatable plug includes an elongated
inflatable sleeve of elastomeric material. The inflatable sleeve
has a first sleeve end sealingly engaging the first support member
to form a first ring of folds wrapped around the first support
member when viewed in cross section generally perpendicular to a
longitudinal axis of the first support member, and a second sleeve
end sealingly engaging the second support member to form a second
ring of folds wrapped around the second support member when viewed
in cross section generally perpendicular to a longitudinal axis of
the second support member. An inner surface of the inflatable
sleeve extends between the first and second inflatable sleeve ends
and substantially defines an expandable inflatable space therein. A
fluid supply inlet is disposed at the first end of the apparatus.
The inlet is positioned in fluid communication with the inflatable
space and operable to deliver fluid into the inflatable space to
inflate the inflatable space. The apparatus further includes an
elongated outer sleeve that substantially surrounds the inflatable
sleeve and has an inner surface. The outer surface of the
inflatable space is shiftable with respect to the inner surface of
the outer sleeve during inflation of the inflatable space. The
outer sleeve has a first sleeve end sealingly engaged around the
first ring of folds to form a third ring of folds and a second
outer sleeve end sealingly engaged around the second ring of folds
to form a fourth ring of folds. The third and fourth ring of folds
are positioned radially outward from the first and second ring of
folds respectively.
[0004] Another inflatable plug is described in U.S. Pat. No.
4,565,222, also assigned to the assignee of the present invention.
The inflatable plug described there includes an inflatable plug of
flexible sheet material that is constructed to form an elongated
cylinder. The ends of the inflatable plug are wrapped around rigid
end supports and then metal collars are placed over the ends of the
inflatable plug. The metal collars are swaged or clamped down to
form a fluid tight seal between the end supports and the collars.
One of the rigid end supports includes an open pipe connectable to
a pressurized air or water supply. The plug is inserted into the
pipeline in the deflated state and maneuvered into the desired
section of the pipeline. Pressurized air or water is then delivered
through the open | pipe to fill the inflatable plug. The inflatable
plug expands to fill the pipeline section and frictionally engages
the inside wall of the pipeline section, thereby sealing or
plugging the pipeline.
[0005] Another prior art inflatable plug may be used to clear a
blockage inside a pipeline as well as to seal the pipeline. Such an
inflatable plug is commonly referred to as a flow-through type
inflatable plug. An example of a flow-through inflatable plug is
described in U.S. Pat. No. 5,353,842, which is also assigned to the
assignee of the present invention. The inflatable plug shown there
includes an elongated cylinder with a central, longitudinal bore
and an expandable covering surrounding the central cylinder. The
expandable covering is comprised of an elastomeric material which
is wrapped around the cylinder. At one end of the inflatable plug,
a first fluid inlet is provided for delivering pressurized air or
water between the outer surface of the cylinder and the inner
surface of the covering and a second fluid inlet is provided for
delivering pressurized fluid to the cylinder bore.
[0006] When the plug is inserted in a pipeline adjacent a pipe
blockage, the first fluid inlet is used to inflate and expand the
space between the covering and the cylinder, such that the outer
surface of the plug sealingly engages the inside surface of the
pipeline section. Then, pressurized fluid is delivered through the
second fluid inlet and into the cylinder bore. This pressurized
fluid is discharged at the opposite end of the cylinder bore in the
direction of the pipe blockage, thereby clearing the blockage from
the pipe.
SUMMARY OF THE INVENTION
[0007] The present invention provides an inflatable plug assembly
that includes a first inflatable plug connected to a second
inflatable plug by an elongated flexible tensile member and a fluid
pressure hose. Each inflatable plug has a plurality of ports that
may be connected to a fluid pressure source, plugged, or left
unplugged depending upon the application. The second inflatable
plug may be inflated either simultaneously with the first plug, or
independently of the first plug. Each inflatable plug also has a
fluid flow-through conduit.
[0008] The invention also provides a method for sealing a defined
section of pipe. A first inflatable plug and a second inflatable
plug are positioned in a spaced apart relation in a section of
pipe, the first and second inflatable plugs being connected by an
elongated flexible tensile member and by a fluid pressure hose. The
fluid pressure hose may be connected for either common inflation or
independent inflation. Once the inflatable plug assembly is
positioned in the desired spaced apart relation in the pipe, the
plugs are inflated by connecting the first inflatable plug to a
fluid pressure source. When the inflatable plug assembly has sealed
the defined section of pipeline, the operator may then proceed to
perform the desired function.
[0009] The invention also provides a method for evacuating a
defined section of pipe. After the section of pipeline has been
sealed using a first and second inflatable plug connected for
common inflation, the isolated area can be evacuated for repair or
maintenance. In order to completely evacuate the isolated area, a
hose can be attached to the fluid flow-through conduit of the first
inflatable plug. The opposite end of the fluid flow-through conduit
of the first plug is attached to a hose that is connected to a pump
for removal of material located in the isolated area. The fluid
flow-through conduit of the second plug is capped to seal the
isolated area. The fluid is pumped from the isolated area until all
material has been evacuated. The operator may then perform the
desired repair or maintenance on the section of pipeline. When
replacing a valve in the pipeline, for example, a plug assembly may
be inserted into the pipeline such that it is positioned both
upstream and downstream of the valve to thereby isolate the valve
from the pipeline system and to allow for removal of the old valve.
Inflatable plug assemblies may also be used with existing pipeline
valves to safely isolate an area where hot work is to be
performed.
[0010] The invention also provides a method for pressure testing a
defined section of pipe. After a section of pipeline has been
sealed using a first and second inflatable plug connected for
common inflation, the isolated area can be pressure tested. The
flow-through conduit of the first plug is set up similar to the
evacuation process with the exception of the pump forcing fluid
into the isolated area instead of removing it from the isolated
area. A pressure testing device is connected to the independent
inflation conduit which is in fluid communication with the isolated
area. As the pump fills the isolated area with pressurized fluid,
the pressure testing device produces an output indicating the
pressure in the area. The operator can fill the isolated area to
whatever pressure is needed to assure the segment of pipeline
retains the ability to withstand predetermined pressure levels.
[0011] The invention also provides a method for fluid flow through
a defined section of pipeline. After the section of pipeline has
been sealed using a first and second inflatable plug connected for
either common inflation or independent inflation, the fluid can
flow through the inflatable plug assembly until the broken pipe
segment is repaired or replaced. The flow-through conduit of the
first plug is connected to the flow-through conduit of the second
plug by connecting a flexible hose to the threaded interior ends of
the first and second plugs. The threaded exterior ends are also
left open to allow fluid to flow freely through the assembly. The
fluid ports that are not used are plugged.
[0012] The invention also provides a method for plugging a pipeline
wherein multiple plugs are used in series to present a greater
friction force in opposition to the pressure in the pipeline. The
inflatable plugs are used in series and the multiple plugs are set
up for common inflation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a cross section elevation view of a pipe sealing
apparatus embodying the invention, and shown inserted in a section
of a pipeline and in the inflated state.
[0014] FIG. 2 is an enlarged view of the pipe sealing apparatus
shown in FIG. 1.
[0015] FIG. 3 is a view similar to FIG. 1 and showing the pipe
sealing plugs inflated by two different fluid pressure sources.
[0016] FIG. 4 is a view similar to FIG. 1 and showing the pipe
sealing apparatus used to evacuate a section of pipeline.
[0017] FIG. 5 is a view similar to FIG. 1 and showing the pipe
sealing apparatus used to pressure test a section of pipeline.
[0018] FIG. 6 is a view similar to FIG. 1 and showing the pipe
sealing apparatus used to isolate a broken section of pipeline and
provide a fluid conduit through the section of broken pipeline.
[0019] FIG. 7 is a view similar to FIG. 1 and showing the pipe
sealing apparatus as including multiple plugs for sealing the
pipeline.
[0020] Before one embodiment of the invention is explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangements
of the components set forth in the following description or
illustrated in the drawings. The invention is capable of other
embodiments and of being practiced or being carried out in various
ways. Also, it is understood that the phraseology and terminology
used herein is for the purpose of description and should not be
regarded as limiting. The use of "including" and "comprising" and
variations thereof herein is meant to encompass the items listed
thereafter and equivalents thereof as well as additional items.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] FIG. 1 illustrates a pipe sealing apparatus embodying the
present invention. More specifically, FIG. 1 depicts an inflatable
plug assembly 10 housed in a section of pipeline 12 and in the
inflated state. The inflatable plug assembly 10 includes two
inflatable plugs 14 and 16 connected in series by a fluid pressure
hose 18 and an elongated flexible tensile member 20. The elongated
flexible tensile member 20 can be a chain, cable, rod, rope, wire
or any other tensile force transmitting arrangement. The elongated
flexible tensile member 20 is shorter than the fluid pressure hose
18 to assure the fluid pressure hose 18 is not stretched beyond its
limits and broken. The elongated flexible tensile member 20 can be
any length desired based upon the length of the section of pipeline
being worked on.
[0022] As shown more clearly in FIG. 2, each inflatable plug is
comprised of two spaced sections of pipe 22 and 24 or other rigid
tubes joined together by an elongated fabric bag 26. The plug forms
a generally elongated body having a rigid leading end 28, an
expandable and flexible middle section 30, and a rigid trailing end
32. Each of the leading end 28, the trailing end 32, and the middle
section 30 is positioned about a common longitudinal axis of the
inflatable plug assembly. The middle section, or elongated fabric
bag 30, has one end wrapped around a central part of the leading
pipe section 24, and is secured thereto by a collar 34. The collar
34 is swaged so as to firmly compress the fabric of the middle
section 30 to the pipe 24. The opposite end of the elongated bag 30
is wrapped around the central part of the other section 22 of pipe
and is similarly clamped by a swaged collar 36. Specific
construction of the middle section material and method of
constructing such is shown and described in U.S. Pat. No.
5,901,752, which is incorporated herein by reference.
[0023] Each of the inflatable plugs 14 and 16 also includes a first
port 38 that extends through the wall of the trailing pipe section
32, and connects to a conduit 40 housed in the pipe 22 and
extending along the length of the pipe 22 to a second port 42 that
communicates with the interior of the inflatable middle section 30.
The inflatable plug also includes a third port 44 that extends
through the wall of the trailing pipe section, and connects to a
conduit 46 that is connected to a pressure hose fitting 48 at the
interior end of the trailing pipe section 22. A fluid pressure hose
50 connects the pressure hose fitting 48 to a second pressure hose
fitting 52 at the interior end of the leading pipe section. In the
illustrated construction the fluid pressure hose 50 is formed from
a flexible material to allow for insertion of the inflatable plug
into the pipeline. In some applications, it may be necessary to
insert the plug vertically downwardly through an opening in the
pipe wall and then turn the plug 90.degree. so that it can be
inserted horizontally into the pipe. If the inflatable plug is
relatively inflexible, such manipulation of the plug can be
difficult. It is for the same reason that the deflated plug
diameter is relatively small. The second pressure hose fitting 50
is connected to a complementary conduit section 54 that is in turn
connected to a fourth port 56 that extends through the wall of the
leading end 28 of the inflatable plug. The leading end 28 may also
have a fifth port 58 that communicates with the interior of the
middle section 30. The fifth port extends through the wall of the
leading end 28 and is connected by a hose 60 to a sixth port 62
that extends through the wall of the inner end of the leading end
28. The second inflatable plug has a similar construction to the
first inflatable plug, however, it may simply have a port that is
in fluid communication with the middle section. Other ports may be
provided and plugged when not in use.
[0024] The leading pipe section 24 includes a projecting end 64
that is threaded for selective attachment of a hose (not shown). In
the illustrated arrangement the threaded projecting end is capped
by a cap 66 threaded onto the end 64. The trailing end similarly
includes a threaded end 68 capped by a cap 70. The interior ends of
pipe sections 22 and 24 are joined by a flexible hose 72 having
opposite ends secured to the respective pipes 22 and 24 by clamps
or bands 74 and 76.
[0025] In one preferred embodiment of the invention, the port 38 is
a threaded bore or inlet that is fitted with a compression fitting
assembly onto which a high pressure flexible conduit 78 (i.e.
rubber hose) is connected. The flexible conduit 78 is connectable
to an external source of pressurized fluid (not shown), such as
compressed air, which is used to deliver pressurized fluid to the
inflation conduit 78 and into the inflatable middle section 30.
[0026] FIGS. 1 and 2 illustrate a method for use of an inflatable
plug assembly 10 wherein a single fluid pressure source is used for
inflation of both inflatable plugs 14 and 16. In order to inflate
the second inflatable plug, port 38 of the first inflatable plug 14
is connected to a fluid pressure source through fluid line 78. The
connection at port 38 will be utilized to fill the inflatable
middle sections of the both the first inflatable plug 14 and second
inflatable plug 16. Fluid pressure from port 38 is supplied through
conduits 40, 60, 18 and 80 to inflate the second inflatable plug
16. Port 56 of the second inflatable plug 16 can be closed by a
threaded plug 84.
[0027] FIG. 3 illustrates a method for use of the inflatable plug
assembly embodying the invention wherein the two inflatable plugs
14 and 16 are inflated from separate or independent pressure
sources. Independent inflation of the second plug may be useful in
order to permit one of the two inflatable plugs to be inflated
under greater pressure than the other of the inflatable plugs. In
order to inflate the second inflatable plug independently of the
first inflatable plug, port a first source of fluid pressure is
connected through conduit 78 and port 38 to the first inflatable
plug and a second source of fluid pressure is connected through
conduit 84 to port 44 of the first inflatable plug. Fluid pressure
is provided from conduit 84 through conduit 46, 50 and 54 to a tube
86 which connects to port 38 of the second inflatable plug 16 for
inflation of the second inflatable plug 16. Port 58 of the second
inflatable plug is plugged by a threaded plug 88. The connection at
port 38 will be utilized to fill the inflatable middle section of
the second inflatable plug 16.
[0028] FIG. 4 illustrates a method for evacuation of a segment of a
pipeline using a pipe sealing assembly embodying the invention. The
pipe sealing assembly for this application includes two inflatable
plugs 14 and 16 in series that are connected by a tensile member 90
and a fluid pressure hose 86. The inflatable plugs are connected
for common inflation with fluid pressure hose 86 joining port 58 of
the first inflatable plug 14 to port 38 of the second inflatable
plug 16. A hose 92 is connected from an external pump to the
threaded end 68 of the first inflatable plug for removal of fluid
and material from the isolated area of pipeline. A hose 94 is
attached to the threaded end 64 of the first inflatable plug. The
hose 94 needs to be long enough to travel from the threaded
connection 64 to the lowest area in the isolated area of pipeline.
The threaded ends 68 and 64 of the second plug 16 are capped with a
threaded caps thereby blocking the flow-through capability of the
second inflatable plug. The pipe sealing assembly is inserted into
the section of pipeline through an opening in the pipeline,
positioning the inflatable plugs in spaced apart relation in the
pipe by pulling the assembly with a tensile force transmitting
arrangement so as to define a length of pipe volume between the
plugs. The spaced apart plugs are then commonly inflated. Once the
pipe sealing assembly seals off the defined section of pipe, steps
can be taken to evacuate the isolated area of pipeline for routine
maintenance or repair. The fluid is pumped by an externally located
pump from the isolated area until all material has been evacuated.
The operator may then perform the desired repair or maintenance on
the section of pipeline.
[0029] FIG. 5 illustrates a method for pressure testing a segment
of pipe using a pipe sealing assembly embodying the invention. The
illustrated pipe sealing assembly for this application includes two
inflatable plugs 14 and 16 in series that are connected by an
elongated tensile member 90 and a fluid pressure hose 86. The
inflatable plugs 14 and 16 are connected for common inflation, and
a pressure sensing device is connected to port 44 of the first
inflatable plug. Port 56 of the first inflatable plug 14 is left
open to the isolated area of pipeline. The pipe sealing assembly is
inserted into the section of pipe through an opening in the pipe,
with the inflatable plugs positioned in spaced apart relation in
the pipeline so as to define a volume between the plugs 14 and 16.
The spaced apart plugs 14 and 16 are then commonly inflated steps
sealing off a section of pipeline. Steps can then be taken to test
the pressure of the isolated area of pipeline. The isolated area
may first be evacuated of any material to allow for pressure
testing using uniform fluid. Fluid is then forced into the space
between the inflated spaced apart plugs. This may be done by
forcing fluid through a hose 92 connected to the threaded end 68 of
the first inflatable plug. The threaded end 64 of the first
inflatable plug is left open thereby allowing fluid pumped into the
flow-through conduit to flow into the isolated area. A pressure
reading can be obtained from the pressure sensing device 96 that is
monitoring the pressure within the isolated area of pipeline. Once
pressure testing is completed, the area can be depressurized by
removing fluid and then the section of pipeline can return to
normal operation.
[0030] FIG. 6 illustrates a method for using the pipe sealing
assembly embodying the invention to provide for fluid flow through
a broken or damaged section of pipe or pipeline 12. The pipe
sealing assembly used in this method includes two inflatable plugs
14 and 16 in series that are connected by an tensile member 90 and
a fluid pressure hose 86. The inflatable plugs 14 and 16 may be
connected for either independent or common inflation, and a
flexible hose 98 is connected between the threaded end 64 of the
first inflatable plug 14 and the threaded end 68 of the second
inflatable plug 16. This hose thereby makes a continuous fluid
conduit from the threaded end of the first inflatable plug to the
threaded end of the second inflatable plug. All ports that are not
being used are plugged to seal the inflation conduits off from
material in the pipeline. The pipe sealing assembly is inserted
into the section of pipe through an opening in the pipe,
positioning the inflatable plugs in spaced apart relation in the
pipe so as to define a length of pipe volume between the plugs. The
first inflatable plug will commonly be upstream of a break in the
pipe and the second inflatable plug will commonly be downstream of
a break in the pipe. The spaced apart plugs are then inflated. Once
the pipe sealing assembly is sealing off the defined section of
pipe, the fluid in the pipeline can flow freely through the
flow-through type inflatable plug assembly until the broken pipe
segment is repaired or replaced.
[0031] FIG. 7 illustrates a method for sealing a pipe using a pipe
sealing assembly having multiple inflatable plugs. The pipe sealing
assembly for this application includes at least two inflatable
plugs in series that are connected by elongated flexible tensile
members and fluid pressure hoses. The inflatable plugs are
preferably connected for common inflation. The threaded ends of the
leading and trailing ends of the inflatable plugs are capped using
a threaded nipple. The ports that are not used are also plugged
with a threaded plug. The pipe sealing assembly is inserted into
the section of pipe through an opening in the pipe, positioning the
inflatable plugs in spaced apart relation in the pipe so as to
define pipe volumes between the plugs. The spaced apart plugs are
then commonly inflated. Once the pipe sealing assembly is sealing
off the defined section of pipe, a seal resisting the fluid
pressure of the fluid in the pipeline should be established. If the
fluid pressure in the pipeline is applying a force that is still
greater than the friction force of the inflatable plug assembly,
the assembly may be deflated and additional inflatable plugs added
to provide greater resistance to the fluid pressure force of the
fluid in the pipeline.
[0032] Various features of the invention are set forth in the
following claims.
* * * * *