Note: Descriptions are shown in the official language in which they were submitted.
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CROSS-LINE PLUGGING SYSTEM AND LOCKING PLUG
REFERENCE TO PENDING APPLICATIONS
This is a continuation-in-part of United States Patent Application No.
11/133,514, filed May 20, 2005 and entitled Cross-Line Plugging System. The
application is not related to any federally sponsored research or development.
BACKGROUND OF THE INVENTION
1. Field of the Invention.
This invention relates to a system and method of providing access to the
interior of a branch pipeline, referred to as a "cross-line" that intersects
with a main
pipeline of equal or greater diameter.
II. Description of the Prior Art.
Pipelines are used in all parts of the world for the transportation of
hydrocarbon products including primarily natural gas and crude oil. These
commodities are exceedingly valuable and, in fact, indispensable to the modem
standard of living enjoyed throughout the world. However, in addition to being
valuable, they are also hazardous. Such hazards include danger to life as can
be a
consequence of explosions or fires from leaked oil or gas products and, in
addition,
these products can be harmful to the environment. For these reasons, it is
important
that pipelines be periodically inspected and/or evaluated for proper repair
and
maintenance. Pipelines are usually buried under the earth's surface to protect
them
against hazards that would exist if they were laid on the earth's surface. In
addition,
due to the increased amount of offshore oil and gas exploration, many
pipelines today
are laid at the bottom of an ocean, that is, on the ocean floor. For these
reasons, the
exterior surfaces of pipelines are not readily available for visual
inspection. As a
consequence, the most economical and effective way of inspecting pipelines is
by
transmitting pigs that are moved through the pipelines by fluid flow, that is,
by the
flow of natural gas or crude oil. For background information as to the
application and
use of pipeline pigs, reference may be had to an article entitled
"Fundamentals of
Pipeline Pigging", authored by Burt VerNooy, appearing in Pipeline Industry,
September/October 1980, published by the Gulf Publishing Company of Houston,
Texas.
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A particular problem is encountered with the use of pipeline pigs for
inspecting cross-lines, that is, pipelines that interconnect between other and
usually,
larger diameter pipelines. While primary pipelines may extend for miles or
even
hundreds of miles, cross-lines are typically of much shorter length, such as a
few
hundred feet up to a few miles. It is sometimes difficult and always expensive
to
install pig launching and receiving facilities for such cross-lines.
The term "cross-line" as used herein includes a pipeline that interconnects
between other pipelines, as above stated, and also branch lines, that is, a
smaller
diameter pipeline that extends from a main pipeline that does not necessarily
connect
to another main pipeline but that connects such as to a storage facility, a
processing
plant or the like. Thus, "cross-lines" herein includes branch lines.
For additional background information relating to this invention, reference
may be had to the following previously issued United States patents.
Patent Inventor Title
Number
408,826 Conroy Cross For Gas Mains or Pipes
1,825,034 Weatherhead, Sectional Pipe Coupling
Jr.
2,546,502 Harrington Means For Incorporating Solid Fat In Liquid Fatty
Mixtures
2,563,244 Holicer Fluid Control Mechanism
2,913,259 Rings Sidebranch Fitting For Main Supply Pipe
3,135,278 Foord et al. Loading Pipeline Pigging System and Method
3,373,452 Watts Manifold Assembly For Hot and Cold Water Faucet
Pairs Arranged Back to Back
3,510,156 Markowz Device For Transmitting Flows
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Patent Inventor Title
Number
3,766,947 Osburn Fluid Tight Closure
4,579,484 Sullivan Underwater Tapping Machine
4,708,372 Arima et al. Cross Piping Construction
4,880,028 Osburn et al. Completion Machine
5,439,331 Andrew et al. High Pressure Tapping Apparatus
5,678,865 Anderson Tank Tee Unit
5,967,168 Kitani et al. Method of Connecting Branch Pipe
6,196,256 Klampfer Manifold
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BRIEF SUMMARY OF THE INVENTION
The invention herein provides methods, apparatus and systems for providing
access to the interior of a cross-line that intersects with a main pipeline of
equal or
greater diameter. The method includes the steps of first attaching a side
outlet fitting
to the exterior of the main pipeline on the side thereof diametrically
opposite the point
of intersection of the cross-line. A side outlet may be attached by welding to
the
exterior of the main pipeline a saddle-type device having a portion that fits
against the
exterior wall of the pipeline with an integral branch fitting. After a side
outlet fitting
is welded to the main pipeline, a full opening valve is affixed to the outlet
fitting. The
typical side outlet fitting is of the type having a flange. A full open valve
can be
affixed to the flange fitting.
A hot tapping system is then affixed to the valve. The following two U.S.
patents illustrate and describe apparatus and systems that can be used to tap
a pipeline
under pressure.
1. 4,579,484 entitled "Underwater Tapping Machine", Sullivan,
issued April 1, 1986;
2. 5,439,331 entitled "High Pressure Tapping Apparatus, Andrew
et al, issued August 8, 1995"
In the present case, such hot tapping system is applied to the exterior of the
valve and with the valve open, the hot tapping system can extend through it to
cut an
opening in the sidewall of the main pipeline. While in some instances it may
be
necessary to cut an opening in the pipeline that is only as large as the
interior diameter
of the cross-line, nevertheless, for practical purposes, it is normally
desirable that an
opening be cut in the sidewall of the main pipeline substantially equal to its
internal
diameter.
After an opening is cut in the wall of the main pipeline the hot tap machine
is
removed and equipment can then be attached to the valve for use in inserting
inspection pigs into the pipeline. As a practical step, after the hot tap
machine has
been employed, a pig launcher may be affixed to the valve. Thereafter, with
the valve
open, a pig can be launched through the valve and through the fitting attached
to the
main pipeline diametrically through the main pipeline and into the cross-line.
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Thereafter, the pig moves by fluid flow, either gas or liquid, through the
cross-line to
perform any of the usual services that can achieved by a pig. For instance,
pigs can
be employed to make geometry measurements to detect indentations, buckles or
other
obstructions in the pipeline. Pigs can be employed for cleaning the interior
of the
cross-line. Pigs can be employed for detecting corrosion in the walls of the
cross-line
by the use of magnetic flux leakage or sonic inspection technologies.
In addition to being able to introduce a pig into a cross-line by the methods
and systems of this invention, other activities can be accomplished that do
not employ
a pig. For instance, by the use of locking pipe plug, the cross-line can be
closed
adjacent the point where it intersects the main pipeline. With the cross-line
closed,
pressure tests can be made. Further, by closing off the cross-line at both
ends, it can
be depressurized and repairs can be made to it without stopping the flow of
the fluids
through the main pipeline.
Cross-lines typically extend between two main pipelines. In this case it is
desirable to provide access to both ends of the cross-line which is
accomplished by
the steps above indicated being employed on both main pipelines. That is,
access can
be obtained through the main pipelines into both the opposite ends of the
cross-line.
The invention herein further provides an apparatus for use when inspecting,
testing or repairing a cross-line after access has been provided through the
main
pipelines to which the cross-line attaches. A branch shield pig guide is
disclosed that
can be installed in a main pipeline to prevent a pig passing through the main
pipeline
from being inadvertently diverted into the cross-line. A flow-through pig
guide is
also disclosed to ensure the passage of a pig diametrically through a main
pipeline and
into a cross-line. Such flow-through pig guide is always removed after the
pigging
operation is complete through the cross-line. After access is provided to the
cross-line
using the concepts of the present invention, locking pipe plugs or cross-line
pluggers,
both of which are disclosed herein, can be employed for closing off the ends
of the
cross-line for reasons above described.
A better understanding of the invention will be obtained from the following
detailed description of the preferred embodiments and claims, taken in
conjunction
with the attached drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will now be described in further
detail. Other features, aspects, and advantages of the present invention will
become
better understood with regard to the following detailed description, appended
claims,
and accompanying drawings (which are not to scale) where:
Figure 1 is a diagrammatic, isometric view showing an excavation in the earth
in an area having two main pipelines and a cross-line. This figure shows the
method
of this invention for providing access to the cross-line by cutting a hole in
the side
wall of each of the main pipelines, each hole being diametrically opposite the
attachment of the cross-line.
Figure 2 is an isometric view showing a main pipeline in dotted outline and
showing, in solid line, a flow-through pig guide that is temporarily inserted
through a
main pipeline when a pig is being launched into the cross-line.
Figure 3 is an isometric view of a branch shield pig guide that can be
inserted
into a main pipeline after access has been provided to a cross-line to restore
pigability
of the main pipeline. That is, the branch shield pig guide is used to ensure
that a pig
passing through a main pipeline is not inadvertently diverted into a cross-
line.
Figure 4 is an exploded view of a locking pipe plug that can be used for
closing the interior of a cross-line and showing a tool that is used for the
installation
of the locking pipe plug.
Figure 5 is a cross-sectional view of a locking pipe plug of the type shown in
Figure 4. In this view the locking pipe plug is in the non-expanded condition
as when
it is being inserted into or removed from the interior of the cross-line.
Figure 6 shows the locking pipe plug of Figures 4 and 5 after having been
actuated to a secure position within the interior of the cross-line in a
manner to
provide leak proof closure of the cross-line.
Figure 7 is a side view of the cross-line plugger that can be used to close
off
the opening in a main pipeline where communication is provided with a cross-
line.
Figure 8 is a side view of the cross-line plugger rotated 90 with respect to
Figure 7.
Figure 9 is an isometric view of a cross-line plugger of Figures 7 and 8.
Figure 10 is an elevational front view of the cross-line plugger of Figures 7,
8
and 9.
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Figure 11 is an elevational rear view of the cross-line plugger of Figures 7,
8,
9 and 10.
Figure 12 is an isometric view of a typical instrument pipeline pig, shown in
small scale, that can be launched into the cross-line after the methods of
this invention
are employed to provide access diametrically through main pipelines to which
the
cross-line connects.
Figure 13 is an elevational view, shown partially in cross-section, of an
improved locking pipe plug of the type shown in Figures 5 and 6. The improved
locking pipe plug includes, among other advantages, a rotation resistor.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
It is to be understood that the invention that is now to be described is not
limited in its application to the details of the construction and arrangement
of the parts
illustrated in the accompanying drawings. The invention is capable of other
embodiments and of being practiced or carried out in a variety of ways. The
phraseology and terminology employed herein are for purposes of description
and not
limitation.
Elements illustrated in the drawings are identified by the following numbers:
Earth's surface 70 Short length tubular portion
12 Excavation 72 Bars
14 First main pipeline 74 Bars
16 Second main pipeline 76 Locking pipe plug
18 Cross-line 76A Improved locking pipe plug
Connection of the cross-line 78 Tightening nut
22 Branch fitting 80 Ram expander
24 Flange fitting 82 Shaft
26 Valve 84 Base member
28 Pig launcher 86 Tubular portion
Pipeline pig 88 Radial flange
32 Hydraulic ram 90 Compression member
34 Plugging machine 92 Seal member
36 Pig signal device 94 Actuation member
38 Branch fitting 96 Cup portion
Flange fitting 98 Frusto-conical surface
42 Valve 100 Segmented slips
44 Pig catcher 102 Base portion
46 Hot tap machine 104 Bolt
48 Flow-through pig guide 106 Bolt head
Tubular body 108 Cross-line plugger
52 Slotted openings 110 Back up plate
54 Outer diameter 112 Elastomer seal
56 Locking ring flange 114 Attachment guide
58 External groove 116 Pipeline pig
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60 Branch shield pig guide 118 Bypass line
62 Tubular body portion 120 Bypass valve
64 Lateral tubular portion 126 Retainer spring
66 Locking ring flange 128 External threads
68 Circumferential groove 132 Rotation resistor
134 Wire brush 152 Inner end portion
136 Wires 154 Threaded opening
138 Outer end 156 Interior recess
140 Pipe inner surface 158 Pipe plug
142A, B Face plates 160 Washer
144 Opening 162 Internal threads
146 Bolt 164 Flange
148 Threaded opening 166 Openings
150 Holder
Referring first to Figure 1, an environment in which the principles of this
invention can be practiced is illustrated. This figure shows the earth's
surface 10
having an excavation 12 that reveals a first main pipeline 14, a second main
pipeline
16 and a cross-line 18. This invention provides improved methods, systems and
apparatuses for verifying the integrity of cross-line 18.
The first step in practicing the invention to provide access to cross-line 18
is to
affix a branch fitting 22 to the exterior of primary pipeline 14 on the side
thereof
diametrically opposite the point of intersection 20 of cross-line 18. The term
"cross-
line" could equally as well be "branch pipeline" as either term is indicative
of a line
that extends perpendicularly from a primary pipeline. The branch fitting 22
needs to
be of a diameter at least equal to the diameter of cross-line 18 but
preferably is of a
diameter equal to that of the main pipeline 14. Such branch fitting will
typically
include a flange 24 which receives the attachment of a full opening valve 26.
After
valve 26 has been attached, then a hot tap machine (not shown) is secured to
the
valve. The use of hot tapping machines to provide access to the interior of a
pipeline
is well known in the industry. For specific teachings of the construction,
operation
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and methods of use of hot tapping machines, reference may be had to the
following
United States Patents:
4,579,484 entitled "Underwater Tapping Machine"; and
5,439,331 entitled "High Pressure Tapping Apparatus", that have been
previously identified.
By use of a hot tapping machine a shell cutter (not shown) is extended through
valve 26, flange 24 and branch fitting 22 to engage the exterior sidewall of
main
pipeline 14 so that an opening is cut in the side wall of main pipeline 14.
The opening
is diametrically opposite the connection 20 of cross-line 18 to the main
pipeline 14.
After such large diameter opening is cut in the side wall of main pipeline 14,
the piece cut out of the pipeline is removed through valve 26. Valve 26 can
then be
closed and the hot tapping machine (not shown) can be removed and in place of
the
hot tapping machine, a pig launcher 28 is attached to valve 26. Pig launchers
are well
known in the pipeline industry. Essentially a pig launcher is a device that
permits, at
atmospheric pressures, a pipeline pig such as the pipeline pig 30 illustrated
in Figure
1, to be positioned within the launcher. The pig launcher is then hermetically
sealed.
Valve 26 can then be opened and by means such as a hydraulic ram 32, pipeline
pig
30 can be pushed out of pig launcher 28, through valve 26 and branch fitting
22, and
diametrically through main pipeline 14 into the interior of cross-line 18. By
force of
fluid flow, either liquids or gases, the pig can then be caused to move
through cross-
line 18. In Figure 1, a pipeline pig 30 is indicated by dotted outline as
moving
through cross-line 18.
In order to ensure the passage of a pig 30 through cross-line 18, increased
fluid flow pressure can be obtained by temporarily closing or at least
partially closing
main pipeline 14. For this purpose, a plugging machine generally indicated by
the
numeral 34 can be affixed to pipeline 14 downstream of the cross-line
connection. A
plugging machine which functions as previously described can provide an
opening
into the interior of main pipeline 14 through which a flow blockage apparatus
(not
shown) can be inserted for temporarily blocking or at least reducing fluid
flow
through the main pipeline. Such flow blockage mechanism is well known in the
pipeline industry and is commercially available from T.D. Williamson, Inc. of
Tulsa,
Oklahoma, U.S.A.
With fluid flow blocked or at least restricted by way of a plugging machine 34
and the insertion of a flow blockage mechanism, the pipeline pig 30 will be
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through the interior of cross-line 18. The pig 30 may be of any type that is
currently
used in the industry including geometrical measurement pigs, cleaning pigs,
corrosion
measurement pigs and so forth. Movement through cross-line 18 of the pig can
be
verified by the use of pig signaling devices 36 that are attached to the
exterior of
cross-line 18. Two such pig signaling devices are shown in Figure 1.
In Figure 1 a second branch fitting 38 is shown as having been attached to
second main pipeline 16 opposite the connection of cross-line 18. As with
first
pipeline 14, after the branch fitting 18 is attached with a flange 40, a valve
42 is
employed. By accessing the exterior surface of main pipeline 18 through valve
42, a
hot tapping machine (not shown) may be employed to provide an opening in the
wall
of second main pipeline 16. After such opening is provided, the hot tapping
machine
is removed and a pig catcher 44 can be installed. In this way, after the
pipeline pig 30
has traversed through cross-line 18 to perform any of the functions that are
commonly
available by the use of a pipeline pig, the pig is captured within catcher 44
and may be
removed.
As has been described, to augment fluid flow pressure through cross-line 18 to
cause pig 30 to move therethrough, it may be desirable to block the fluid flow
that
normally occurs within second main pipeline 16 and for this reason, a hot tap
machine
can be employed so as to provide an opening into the interior of second main
pipeline
16 and the insertion of flow blockage equipment with a plugging machine to
temporarily block or restrict fluid flow. Thus with flow blocked or restricted
downstream of the cross-line in first main pipeline 14 and blocked or
restricted
upstream of the cross-line in second main pipeline 16, fluid flow pressure
through
cross-line 18 is optimized to ensure movement of pipeline pig 30 through it
and into
position for retrieval.
After the opening through the side wall of first pipeline 14 has been
accomplished as described, it is important that provisions be made so that
when
pipeline pig 30 is injected diametrically through the main pipeline that the
pig will
pass into cross-line 18 and not become lodged within the main pipeline. For
this
reason, a flow-through pig guide as generally indicated by the numeral 48 is
employed. The flow-through pig guide is illustrated in Figure 2. Flow-through
pig
guide 48 is inserted diametrically through first main pipeline 14 that is
illustrated in
dotted outline in Figure 2, the flow-through pig guide 48 passing through
valve 26.
Flow-through pig guide 48 has a tubular body 50 with slotted openings 52
therein.
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The outer end portion 54 is of external diameter so that it can extend
telescopically
within the interior of cross-line 18.
The inner end of flow-through pig guide 48 has a locking ring flange 56 with
an external circumferential groove 58 therein. Flange fittings 24 and 40, as
previously identified, are preferably of the type that facilitate receiving an
internal
device and removably locking it in place. Such a device is illustrated and
described in
detail in United States Patent No. 3,766,947 entitled "Fluid-Type Closure",
issued
October 23, 1973. This patent teaches a type of flange that has provisions for
actuation of a plurality of locking elements that can be moved radially
inwardly or
radially outwardly by adjustment of screw mechanisms on the exterior of the
flange
(not shown in Figure 1). These locking elements are moved into external
circumferential groove 58 to thereby hold flow-through pig guide 48 in
position as it
extends diametrically through pipeline 14.
The use of the flow-through pig guide ensures, as above indicated, the passage
of a pig 30 through the main pipeline 14 so that the pig passes into cross-
line 18. In
the same manner, a flow-through pig guide as illustrated in Figure 2 is
positioned
diametrically within second pipeline 16 in which case the flange 40 (as seen
in Figure
1) is of the type that has locking elements that can be extended into and
withdrawn
from the circumferential groove 58.
The flow-through pig guide 48 of Figure 2 is used only when a pig is being
launched into or received diametrically through main pipeline 14 or 16 and
thereafter
removed since if left in position they would interfere with the passage of
pigs through
the main pipelines.
After the method of this invention has been employed as has been described to
provide access diametrically through main pipelines 14 and 16 and after
pigging
operations or other work required to be done on cross-line 18 has been
completed, it is
important that the main pipelines 14 and 16 be restored to function in the
manner as if
such work on the cross-line had not been done. That is, it is important that
the
provision of the openings through the walls of main pipelines 14 and 16 do not
interfere with the passage of pipeline pigs through them. For this purpose,
after the
work on the cross-line 18 has been completed, a branch shield pig guide
generally
indicated by the numeral 60 as shown in Figure 3, can then be installed within
the
main pipelines 14 and 16. The branch shield pig guide includes a main short
length
tubular body portion 62 that is of external dimensions slightly less than the
internal
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diameter of main pipeline 14. Extending from tubular body portion 62 is a
lateral
tubular portion 64 that connects the main body portion to a locking ring
flange 66 that
has a circumferential groove 68. Thus, by use of a locking ring system as
illustrated
and described in U.S. Patent No. 3,766,947 as previously mentioned, the branch
shield pig guide 60 can be maintained within the interior of main pipeline 14.
Extending from the tubular body portion 62 is a short length tubular portion
70
of external diameter substantially equal to the interior diameter of cross-
line 18.
When positioned within the interior of main pipeline 14, the short length
tubular
portion 70 extends telescopically within the cross-line to assist in anchoring
the
branch shield pig guide 60 in position. To prevent the possibility of a pig
passing
through main pipeline 14 attempting to enter cross-line 18, paralleled bars 72
close
tubular portion 70. Similar bars 74 are shown closing the lateral tubular
portion 64
for similar reasons, that is, to close off the possibility of a pig attempting
to enter this
passageway. The use of bars 74 is optional since there is no fluid flow
through this
lateral tubular passageway that would tend to cause a pig to enter it whereas
fluid
flow through the short length tubular portion 70 is possible.
The branch shield pig guide 60 is installed through valve 26 as previously
described by means of a hot tapping machine so that such device can be
installed
while the main pipeline 14 is under pressure. Branch shield pig guide 60
includes a
flange closure system 66 to close off flange 24 enabling valve 26 to be
removed and a
blind flange (not shown) installed.
A branch shield pig guide 60 will also be installed in second main pipeline 16
for the same reasons as described with reference to the first main pipeline
14.
After access to cross-line 18 is provided diametrically through main pipelines
14 and 16, it is then possible to seal off both ends of the cross-line 18 to
allow for
pressure testing, as is sometimes required to ensure the integrity of the
cross-line. For
this purpose, a locking pipe plug 76 as generally indicated in Figure 4 and in
greater
detail in Figures 5 and 6 is employed. As shown in Figure 4 the locking pipe
plug 76
has, on the rearward end thereof, a tightening nut 78 that can be grasped by a
ram
expander 80 that is positioned and rotated by a shaft 82. By means of hot
tapping
equipment that controls the axial and rotational position of ram expander 80,
it can be
extended diametrically through the interiors of both main pipeline 14 and 16.
In this
way a locking pipe plug 76 can be inserted in each end of cross-line 18.
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The details of the locking pipe plug are shown in Figure 5. A base member 84
has a tubular portion 86 that is externally threaded and receives nut 78
thereon. The
base portion 84 has an integral radial flange portion 88 that faces a radial
compression
member 90 that is slidable on tubular portion 86. Between radial flange
portion 88
and compression member 90 is a circumferential elastomeric seal member 92. In
the
relaxed position as shown in Figure 5 the seal member is cupped outwardly as
indicated in the cross-sectional view. Received on tubular portion 86 is an
actuation
member 94 having a cupped portion 96. The compression member 90 has a frusto-
conical surface 98 that receives segmented slips 100.
When nut 78 is threadably tightened by rotation of shaft 82 and thereby ram
expander 80 as seen in Figure 4, the threaded advancement of nut 78 towards
base
member 84 moves compression member 90 towards base member radial flange 88,
compressing seal member 92. The segmented slips 100 are concurrently moved
forward and the reaction of the slips with frusto-conical surface 98 causes
the slips to
expand radially outwardly for engagement with the interior of cross-line 18.
In this
way the locking pipe plug 76 is tightly engaged within the interior of cross-
line 18.
With a locking pipe plug at each end of the cross-line, pressure can be
applied to it to
test for leakage. High pressure can be applied to test the bursting strength
of cross-
line 18.
After such tests are completed, each locking pipe plug can be removed by
reversing the rotation of nut 78, and retrieving the plug with expander 80 as
affixed to
shaft 82.
Another way of closing off the opposed ends of cross-line 18 is by the use of
a
cross-line plugger 108 as shown in Figures 7 through 11. This item has a base
portion
102 with a bolt 104 having a head 106 that forms the forward end of the cross-
line
plugger, which is generally indicated by the nunieral 108. Bolt 104 receives
an
arcuate back up plate 110 having an elastomer seal 112 on the forward surface
thereof. The radius of curvature of the back up plate 110 and the forward
surface of
elastomer seal 112 is the same radius of curvature as the interior
circumferential
surface of the main pipelines 14 and 16. The rearward end of the cross-line
plugger
108 is an attachment guide 114.
The cross-line plugger 108 is used in this way: with an opening having been
formed in each of the main pipelines 14 and 16, each ends of cross-line 18 can
be
temporarily closed by inserting through each open valves 26 and 42, a cross-
line
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plugger 108 attached to a rod (not shown) extending from hydraulic cylinder
32.
Cross-line plugger 108 passes diametrically through a main pipeline. The
elastomer
seal 112 of each plugger engages the circumferential area of the internal
cylindrical
wall of a main pipeline that surrounds the opening communicating with cross-
line 18.
In this way the cross-line is plugged off at each end. It should be kept in
mind that the
cross-line plugger 108 is not intended for use to resist high pressure within
cross-line
18 but cross-line pluggers 108 may be used to isolate the cross-line from the
main
pipelines and permit drainage of liquids and gases from it so as to permit
repairs. The
cross-line pluggers are not intended for permanently closing the cross-line.
Figure 12 is a small scale isometric representation of a pipeline pig 116
which
may be of the type used for determining the structural integrity of cross-line
18. Pigs
116 of the type shown in Figure 12 may include highly technical systems such
as for
measurement of corrosion by magnetic flux leakage, or sonic energy
reflections.
Figure 1 illustrates an additional element that is not directly related to the
methods and systems of this invention but that make the inventions herein more
usefiil. Extending from cross-line 18 is a bypass line 118 that connects to
second
main pipeline 16 downstream of branch fitting 38. A bypass valve 120 controls
flow
through bypass line 118. When a pig 30 is launched through branch fitting 22
and
diametrically througli first main pipeline 14, valve 120 is opened. When
pipeline pig
30 gets to near the end of cross-line 18 as shown in dotted outline in Figure
1, the
restriction to fluid flow imposed by the pipeline pig will cause fluid flow
through
bypass line 118, stopping further movement of the pipeline pig which is then
in
position for retrieval by apparatus extending from pig catcher 44. When a pig
is not
being received bypass valve 120 will normally be closed.
Figure 13 illustrates in elevational view, shown partially in cross-section,
an
improved locking pipe plug generally indicated by the numeral 76A. The
improved
locking pipe plug employs the basic concepts of the locking pipe plug
illustrated and
described with reference to Figures 5 and 6 and the components in the improved
locking pipe plug 76A that have the similar structure and function to the
components
in Figures 5 and 6 are provided with the same numbers.
Thus, the embodiment of Figure 13, as compared with the embodiment of
Figures 5 and 6, has these similar functioning components: a base member 84
with a
tubular portion 86 and a radial flange 88; an expansion member 90; an
elastomeric
seal member 92; an actuation member 94 having a cup portion 96; and a frusto-
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conical surface 98 on compression member 90 that receives segmented slips 100.
In
addition to the similarities in the locking pipe plug illustrated in Figures 5
and 6 and
that of Figure 13, Figure 13 shows additional features and improvements.
As has been previously described, segmented slips 100 are formed of metal to
securely lock into the interior wall of the pipe in which the improved locking
pipe
plug 76A is positioned. A retainer spring 126 encircles the segments making up
segmented slips 100 to hold them in contact with frusto-conical surface 98 of
compression member 100.
Actuation member 94 is received slideably on the external threads 128 of
tubular portion 86 of base member 84. When the improved pipe plug 76A is
inserted
into a pipe, rotation of holder 150, with its internal threads 154 engaged in
the
external threads 128 on tubular portion 86, causes actuation member 94 to be
axially
advanced so that it moves the cup portion 96 against segment slips 100 to
thereby
force compression member 90 in the direction towards radial flange 88. This
causes
radially expansion of segmented slips 100 and simultaneously axially advances
compression member 90 towards flange 88, thereby compressing seal member 92.
Thus, threadably rotating holder 150 simultaneously causes segmented slips 100
to
lock against the interior surface of the pipe in which the plug is positioned
and to
radially expand the seal member 92 to seal against the wall of the pipe in
which the
plug is positioned.
When holder 150 is rotated to set the locking pipe plug it is necessary that
the
pipe plug itself not rotate, that is, there must take place threading action
between the
internal threads of holder 150 and external threads 128 on the base member
tubular
portion 86. Stating it another way, it is important that the base member 84 be
restrained from rotation so that actuation member 94 can be slideably
advanced,
through rotation of holder 150, to actuate segmented slips 100 and seal member
92.
The embodiment of the improved locking plug 76A of Figure 13 includes an
innovative system of restraining rotation of the base member 84 so as to
permit
locking a plug in position.
When the improved locking pipe plug 76A is inserted into a pipeline, it is
necessary to rotate holder 150 relative to base member 84 to threadably
advance it and
thus slideably advance the actuation member 94 so that the cup portion 96
presses
against slips 100 to start the process of locking the pipe plug within the
pipe. Thus it
is helpful if a system is provided for resisting the rotation of base member
84
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especially during the initial process of tightening holder 150 on the
actuation member
tubular portion 86. For this purpose, the improved locking pipe plug 76A
includes a
rotation resistor generally indicated by the numeral 132. In Figure 13, a
preferred
embodiment of a rotation resistor 132 is illustrated and is in the form of a
stiff
cleaning brush assembly commonly used on pipeline cleaning pigs. An
alternative
embodiment is essentially of a cylindrical wire brush that is of the type
readily
commercially available and that is typically used as a part of a rotating
mechanism for
cleaning the surface of metallic objects. Thus in the illustrated embodiment,
the
rotation resistor 132 is a wire brush 134 that provides a large number of
radially
extending flexible wires 136. Each of the wires 136 has an outer free end 138
arranged so that the length of the wires 136 extends the outer ends thereof
138 beyond
the normal diameter of the pipe in which the plug is to be used. That is, the
wires 136
are of sufficient lengths so that the outer ends 138 thereof flexibly engage
the pipe
inner surface 140.
Wire brush 134 typically includes opposed face plates 142A and 142B that
retain the wires 136 therebetween. Face plates 142A and 142B each have a
central
opening 144 therein that receives a bolt 146. Bolt 146 is received in a
threaded
opening 148 in base member 84. Thus the rotation resistor 132 is rotatably
locked to
base member 84.
When the improved locking pipe plug 76A is inserted into a pipe to plug the
interior of the pipe against fluid flow therethrough, the wires 136 of the
wire brush
flex or bend so that the pipe plug is relatively easily inserted into the
pipe. The wire
ends 138 engage the internal surface 140 of the pipe and resist the rotation
of the base
member 84. It is to be emphasized that the wire brush 134 does not lock the
plug base
member 84 against rotation but merely resists rotation. All that is required
is that
rotational resistance be applied to the base member 84 as the holder 150 is
rotated to
threadably advance actuation member 94 slideably on tubular portion 86. As the
actuation member 94 advances, segmented slips 100 engage the pipe interior
surface
and immediately serve to resist rotation of the pipe plug. As the advance of
the base
member 84 continues compressive force is applied against seal member 92 so the
outer circumferential surface thereof expands to engage the interior of the
pipe to
further resist rotation. Thus it can be seen that after actuation member 94 is
advanced,
the segmented slip 100 and seal member 92 themselves begin to lock the pipe
plug
against rotation. After this action takes place the rotational resistance
applied by
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rotation resistor 132 is no longer required. Therefore, the function of wire
brush 134
is to merely resist rotation to get the process of anchoring the pipe plug in
the pipe
started. In the same manner, when it is necessary to remove the pipe plug, as
the
holder 150 is threadably retracted, the contact of segmented slips 100 and
seal
member 92 with the pipe interior surface gradually decreases and the
rotational
resistor 132 takes over to allow the actuation member 94 to be retracted to
the point
that the plug can be axially extracted from the pipe.
Another element illustrated in Figure 13 that is not shown in Figures 5 and 6
is
a holder generally indicated by the numeral 150. Holder 150 is tubular with an
inner
end portion 152 having an internally threaded opening 154 therein. The forward
portion of holder 150 is tubular providing an interior recess 156 that
receives a
threaded pipe plug 158. Internally pipe threads 162 at the outer end of the
base
meinber tubular portion 86 threadably and sealably receives pipe plug 158. A
washer
160 has an outer diameter greater than the diameter of holder threaded opening
154.
Thus after holder 150 is threaded onto the outer end of tubular portion 86,
pipe plug
158 and washer 160 may be secured in position to prevent holder 150 from being
inadvertently unthreaded from base member tubular portion 86.
The outer end of holder 150 has a radial flange 164 with openings 166 therein.
Bolts extending through openings 166 (not shown) can be used to hold locking
pipe
plug 76A, for inserting it into a pipe and correspondingly for removing it
after a plug
has been inserted, onto shaft 82 of an insertion tool or onto a tapping
machine 46 of
the type as commonly employed in piping technology and that is readily
commercially available from T.D. Williamson, Inc. of Tulsa, Oklahoma.
While the invention has been described with a certain degree of particularity,
it is manifest that many changes may be made in the details of construction
and the
arrangement of components without departing from the spirit and scope of this
disclosure. It is understood that the invention is not limited to the
embodiments set
forth herein for purposes of exemplification, but is to be limited only by the
scope of
the attached claim or claims, including the full range of equivalency to which
each
element thereof is entitled.
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