U.S. patent application number 12/351479 was filed with the patent office on 2010-07-15 for telescoping double block and bleed plug.
This patent application is currently assigned to TDW Delaware, Inc.. Invention is credited to Tony R. Garrison, Gregory L. Puckett.
Application Number | 20100175771 12/351479 |
Document ID | / |
Family ID | 42316776 |
Filed Date | 2010-07-15 |
United States Patent
Application |
20100175771 |
Kind Code |
A1 |
Garrison; Tony R. ; et
al. |
July 15, 2010 |
TELESCOPING DOUBLE BLOCK AND BLEED PLUG
Abstract
A plugging device for double blocking a section of pipeline or
piping and method for its use includes a first and second sealing
element and at least one cylinder that is extendable along an axial
direction of the pipe between a retracted first position and an
extended second position. A means for actuating the cylinder, such
as a fluid power source, is provided. When the cylinder is in the
extended second position, the sealing element sealably engages an
opposing cut end of the pipe. The sealing element is an elastomeric
sealing element and may be cup-shaped, convex-shaped, or
cork-shaped.
Inventors: |
Garrison; Tony R.; (Bixby,
OK) ; Puckett; Gregory L.; (Broken Arrow,
OK) |
Correspondence
Address: |
GABLE & GOTWALS
100 WEST FIFTH STREET, 10TH FLOOR
TULSA
OK
74103
US
|
Assignee: |
TDW Delaware, Inc.
|
Family ID: |
42316776 |
Appl. No.: |
12/351479 |
Filed: |
January 9, 2009 |
Current U.S.
Class: |
138/91 ; 138/89;
138/94; 29/428 |
Current CPC
Class: |
F16K 1/00 20130101; F16L
55/1608 20130101; Y10T 29/49826 20150115; F16L 55/124 20130101;
F16L 55/105 20130101; F16K 3/188 20130101 |
Class at
Publication: |
138/91 ; 138/89;
29/428; 138/94 |
International
Class: |
F16L 55/10 20060101
F16L055/10 |
Claims
1. A plugging device for double blocking a section of pipeline or
piping comprising: a first and second elastomeric sealing element,
each said sealing element having a rearward surface and a forward
sealing surface; a cylinder in communication with said rearward
surface of at least one of said first and second sealing elements,
said cylinder being extendable between a retracted first position
and an extended second position; and a means for actuating said
cylinder; said forward sealing surface of said at least one of said
first and second sealing elements sealably engaging an opposing cut
end of a pipe when said cylinder is in the second position.
2. A plugging device according to claim 1 further comprising said
means for activating said cylinder being a fluid power source.
3. A plugging device according to claim 2 further comprising a
passageway, said passageway being in communication with said
cylinder and said fluid power source.
4. A plugging device according to claim 1 further comprising at
least one of said first and second sealing elements being selected
from the group consisting of a cup-shaped sealing element, a
convex-shaped sealing element, and a cork-shaped sealing
element.
5. (canceled)
6. A plugging device according to claim 1 further comprising the
opposing cut end of the pipe being selected from the group
consisting of a square-shaped end and a fish-mouth-shaped end.
7. A method of double blocking a section of pipeline or piping
comprising the steps of: (a) cutting and removing a length of pipe
so as to leave two open and opposing pipe ends; (b) inserting a
plugging device between the opposing pipe ends, the plugging device
having two elastomeric sealing elements and at least one cylinder
located between the two sealing elements and in communication with
at least one of the two sealing elements; (c) aligning the plugging
device so that each sealing element is in axial alignment with a
respective opposing pipe end; (d) activating the cylinder to move
between a retracted first position and an extended second position,
the at least one of the two sealing elements being in sealing
engagement with a respective opposing pipe end when the cylinder is
in the extended second position.
8. (canceled)
9. A method according to claim 7 further comprising the two sealing
elements each being selected from the group consisting of a
cup-shaped sealing element, a convex-shaped sealing element, and a
cork-shaped sealing element.
10. A method according to claim 7 further comprising steps (b), (c)
and (d) being carried out within a containment housing.
11. A plugging device for blocking a section of pipe having
diametrically opposed end surfaces, comprising: a first and second
sealing element positioned between said opposed end surfaces, each
said sealing element having a rearward surface and a forward
sealing surface; a cylinder in communication with said rearward
surface of at least one of said first and second sealing elements,
said cylinder being extendable between a retracted first position
and an extended second position, wherein at least one of said first
and second sealing elements is selected from the group comprised of
a cup-shaped sealing element, a convex-shaped sealing element, and
a cork-shaped sealing element; wherein at least one of said sealing
elements is an elastomeric sealing surface; a means for actuating
said cylinder; and said forward sealing surface of said at least
one of said first and second sealing elements sealably engaging a
said end surface of said pipe when said cylinder is in said second
position.
12. A plugging device according to claim 11 wherein said means for
activating said cylinder comprises a fluid power source.
13. A plugging device according to claim 12 including a passageway,
said passageway being in controlled communication between said
cylinder and said fluid power source.
14. (canceled)
15. (canceled)
16. A plugging device according to claim 11 wherein said pipe end
surfaces are selected from the group consisting of a square-shaped
end surface and a fish-mouth-shaped end surface.
17. A method of blocking a section of a pipe having diametrically
opposed end surfaces comprising the steps of: (a) cutting and
removing a length of the pipe so as to leave two open and opposing
pipe end surfaces; (b) inserting a plugging device between said
opposing pipe end surfaces, the plugging device having opposed
sealing elements and a cylinder located between said sealing
elements; (c) aligning the plugging device so that each said
sealing element is in axial alignment with a respective opposing
pipe end surface; (d) activating said cylinder to move between a
retracted first position and an extended second position, at least
one of said two sealing elements being in sealing engagement with a
respective opposing pipe end surface when said cylinder is in said
extended second position; and (e) wherein said two sealing elements
are each an elastomeric sealing element.
18. (canceled)
19. A method according to claim 17 wherein said two sealing
elements are each selected from the group consisting of a
cup-shaped sealing element, a convex-shaped sealing element, and a
cork-shaped sealing element.
20. A method according to claim 17 wherein steps (b), (c) and (d)
are carried out within a containment housing.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to pipe plugs, particularly
plugs for use in pipelines that carry high or low pressure fluids,
high or low temperature fluids, steam, dangerous fluids, and
environmentally hazardous fluids.
BACKGROUND OF THE INVENTION
[0002] "Double block and bleed" is a well-known term of art that
refers to setting two seals in a pipe and opening a bleed port
between the seals to ensure that the first seal is holding. Any
leakage past the first seal is contained by the second seal and
forced to exit through the bleed port. This arrangement ensures
that the pipe is completely sealed, making it safe to work on
downstream of the two seals.
[0003] Achieving double-block and bleed typically requires the use
of a single, metal-to-metal plugging seal or the use of two
independent pluggers and fittings. Both approaches are expensive;
use relatively large, heavy components; and require a lot of
equipment to properly install. Additionally, the metal-to-metal
plugging seal approach does not allow for bypassing pipeline
product through a fitting. If a bypass is required, a second
fitting must be installed upstream of the plugging seal.
[0004] U.S. Pat. No. 7,270,139, issued to Calkins et al. on Sep.
18, 2007, discloses a cam-assisted, wedge actuated, double block
and bleed, metal-to-metal plugger. A pair of wedge members is
forced against a rearward surface of the metal sealing cups to
simultaneously force the cups into metal-to-metal sealing contact
with the sealing surfaces formed by opposing toroidal collars
welded to the exterior of the pipe. Because of the metal-to-metal
seal, requires that each collar have precise face surfaces and that
each collar be precisely welded onto the pipe and accurately spaced
in relation to one another. The plugger cannot seal against the cut
and relatively rough ends of a pipe.
[0005] Another style of double block and bleed plug that eliminates
many of the disadvantages of typical double block and bleed
pluggers is disclosed in U.S. patent applications Ser. Nos.
11/936,182 and 12/256,150, filed by Yeazel et al. on Nov. 7, 2007
and Oct. 22, 2008, respectively. The plug includes pivotally
connected plugging heads which work in combination to seal against
an interior wall surface of the pipe downstream of the access
opening to the pipe. The first plugging head prevents flow of
product in the pipe and the second plugging head captures any
leakage past the first head and forces that leakage out through a
fitting. The plug may include standard sealing elements or an
inflation system used in combination with inflatable sealing
elements or compression packer sealing elements. Although the plug
does not require a precise sealing surface, the plug is not
configured to seal against the cut ends of the access opening to
the pipe.
SUMMARY OF THE INVENTION
[0006] A plugging device for double blocking a section of pipeline
or piping includes a first and second sealing element, each sealing
element having a rearward surface and a forward sealing surface. At
least one cylinder that is extendable between a retracted first
position and an extended second position is in communication with
the rearward surface of the sealing element. A means for actuating
the cylinder-which may be a fluid power source-is provided and the
forward sealing surface engages an opposing cut end of the pipe
when the cylinder is in the second extended position. The sealing
element is an elastomeric sealing element and may be cup-shaped,
convex-shaped element, or cork-shaped element. An internal
passageway or a tubing provides fluid to each cylinder, and each
cylinder may be operated independent of the other. The opposing cut
end of the pipe may be square-shaped or fish-mouth-shaped.
[0007] A method for double blocking a section of pipeline or piping
using a plugging device according to this invention includes the
steps of:
[0008] (a) cutting and removing a length of pipe so as to leave two
open and opposing pipe ends;
[0009] (b) inserting a plugging device between the opposing pipe
ends, the plugging device having two sealing elements and at least
one telescoping cylinder located between the two sealing elements
and in communication with at least one of the two sealing
elements;
[0010] (c) aligning the plugging device so that each sealing
element is in axial alignment with a respective opposing pipe end;
and
[0011] (d) activating the cylinder to move between a retracted
first position and an extended second position, the at least one of
the two sealing elements being in sealing engagement with a
respective opposing pipe end when the cylinder is in the extended
second position.
[0012] A better understanding of the invention will be obtained
from the following detailed description of the preferred
embodiments taken in conjunction with the drawings and the attached
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a cross-sectional view of a section of piping or
pipeline in which a plugging device having two sealing elements has
been inserted. Each sealing element is connected to a telescoping
cylinder arrangement. A locating pin provides a means for locating
the sealing elements in axial alignment with opposing cut, square
ends of the pipe. A tubing connects the telescoping cylinder to a
fluid power source such as a hand pump to actuate the cylinder
between a retracted, first position and an extended, second
position.
[0014] FIG. 1A is a view of a section of pipeline in which the
collars with sealing surfaces have been eliminated.
[0015] FIG. 2 is a view of the plugging device with each cylinder
in its extended second position. The sealing elements sealably
engage the cut ends of the pipe as well as the sealing surfaces of
two opposing collars welded to the exterior of the pipe.
[0016] FIG. 2A is a view of the plugging device with each cylinder
in its extended second position. The forward sealing surface of
each element sealably engages the opposing square end of the pipe
as well as portions of the interior and exterior wall of the
pipe.
[0017] FIG. 3 is a view of the plugging device as it moves into
sealing engagement with a section of pipeline having
fish-mouth-shaped cut ends.
[0018] FIG. 3A is a view of the plugging device taken along section
line 3A-3A of FIG. 3. The forward sealing surface of each sealing
element is a convex-shaped surface to sealably engage the opposing
fish-mouth-shaped ends of the pipe. An internal passageway provides
a source of fluid power to the cylinder.
[0019] FIG. 4 is a view of the plugging device having a cork-shaped
sealing element in sealing engagement with the opposing
fish-mouth-shaped ends of the pipe.
[0020] FIG. 4A is a view of the plugging device taken along section
line 4A-4A of FIG. 4.
[0021] FIG. 5 is a view of the plugging device having a cork-shaped
sealing element in sealing engagement with the opposing
square-shaped cut ends of the pipe.
[0022] FIG. 5A is a view of the plugging device taken along section
line 5A-5A of FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] Preferred embodiments of a telescoping cylinder double block
and bleed plug will now be described with reference to the drawings
and the following elements: [0024] 10 Plugging device [0025] 20
Telescoping arrangement [0026] 22 Housing [0027] 24 First cylinder
[0028] 26 Second cylinder [0029] 28 Fitting [0030] 30 Cylinder rod
[0031] 32 Tubing/passageway [0032] 34 Internal passageway [0033] 36
Bulkhead fitting [0034] 38 Supply line [0035] 40 Fluid source
[0036] 50 Sealing element [0037] 52 Forward sealing surface [0038]
54 Elastomeric seal [0039] 56 Rearward surface [0040] 58
Circumferential surface [0041] 60 Hydraulic cylinder [0042] 70
Sealing element [0043] 72 Forward sealing surface [0044] 74
Elastomeric seal [0045] 76 Rearward surface [0046] 78
Circumferential surface [0047] 80 Containment housing [0048] 82
Fitting [0049] 84 Collar [0050] 86 Sealing surface [0051] 88 Collar
[0052] 90 Sealing surface [0053] 92 Locator pin [0054] 94 Locator
pin receiver [0055] 100 Pipe [0056] 102 Cut end [0057] 104 Internal
wall surface [0058] 106 External wall surface [0059] 112 Cut end
[0060] 114 Internal wall surface [0061] 116 External wall
surface
[0062] In the typical hot tapping application, a fitting--usually
in the form of a flange--is welded on the exterior of a pipe that
has flowing gas or liquid under pressure. The fitting may also be a
spherical fitting that is secured to opposing toroidal collars that
have been welded to the exterior of the pipe. A valve is then
secured to the flange and a hot tapping machine is secured to the
valve. By use of specialized equipment, a hole can then be drilled
through the wall of the pipe while gas or liquid continues to flow
through it. This provides access to the interior of the pipe, such
as for inserting equipment to temporary block flow through the pipe
while repairs are being made. The fish-mouth-shaped ends of the
opposing cut ends of the pipe may be cut to provide square
ends.
[0063] Referring to the drawings and first to FIGS. 1 and 2, a
containment housing 80 for a hot tapping application includes a
fitting 82 and two spaced-apart and opposing toroidal collars 84
and 88. Collars 84 and 88 may be part of fitting 82 or separate
collars welded to an exterior wall surface 106, 116, respectively,
of a section of pipe or pipeline 100. Each collar 84, 88 has a
sealing face surface 86, 90, respectively. Fitting 82 may have a
spherical shape.
[0064] A plugging device 10 is extended out of containment housing
80 until the downward travel of plugging device 10 is arrested by a
locator receiver 94 engaging a locator pin 92. Hydraulic cylinder
60 and cylinder rod 30 provide means for lowering plugging device
10 out of containment housing 80, through the access hole, and into
an interior portion of pipe 100. Locator pin 92 is designed to
ensure that the sealing elements 50, 70 of plugging device 10 are
in axial alignment with pipe 100. A telescoping cylinder
arrangement 20 provides means for each sealing element 50, 70 to
move between a retracted first position and an extended second
position relative to the respective opposing cut ends 102, 112 of
pipe 100.
[0065] Telescoping cylinder arrangement 20 preferably includes two
cylinders 24, 26 in communication with a fluid power source 40.
Cylinders 24 and 26 are housed in a housing 22 which receives a
fitting 28 connected to a tubing 32. A second fitting 36 is
provided on containment housing 80 for connecting fluid supply line
38 and placing line 38 in communication with tubing 32. Fluid power
source 40-which may be a hand pump-supplies air, inert gas or
hydraulic fluid to cylinders 24, 26.
[0066] Sealing elements 50 and 70 have a forward surface 52, 72,
respectively, and a rearward surface 56, 76 respectively. A portion
of the rearward surfaces 56 and 76 are in communication with the
cylinders 24 and 26, respectively. Forward surface 52, 72 has an
elastomeric sealing surface 54, 74. When cylinders 24 and 26 are in
their extended second position, elastomeric sealing surfaces 54 and
74 engage the respective opposing sealing surfaces 86 and 90 of
collars 84 and 88.
[0067] FIGS. 1A and 2A illustrate an alternate preferred embodiment
of plugging device 10. Collars 84 and 88 are eliminated. When
cylinders 24 and 26 are in their extended second position,
elastomeric sealing surfaces 54 and 74 sealably engage the
respective opposing cut ends 102 and 112 of pipe 100 as well as a
portion of the interior walls 104 and 114 and exterior walls 106
and 116, respectively.
[0068] FIGS. 3 and 3A illustrate another preferred embodiment of
plugging device 10. The forward surfaces 52 and 72 of sealing
elements 50 and 70, respectively, are convex-shaped forward
surfaces to sealably engage fish-mouth-shaped cut ends 102 and 112.
Forward surfaces 52 and 72 preferably have an elastomeric sealing
surface 54, 74, respectively. Tubing 32 may be replaced by an
internal passageway 34.
[0069] Referring now to FIGS. 4 to 5A, another preferred embodiment
of plugging device 10 is illustrated. Sealing elements 50 and 70
are frusto-conical or cork-shaped elastomeric or metallic sealing
elements. A circumferential surface 58, 78 of the sealing element
50, 70 sealably engages a portion of the opposing inner wall
surface 104, 114 and cut ends 102 and 112. Cut ends 102 and 112 may
be fish-mouth shaped ends or square-shaped ends.
[0070] While a telescoping plugging device has been described with
a certain degree of particularity, 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. A
telescoping plugging device made according to this disclosure,
therefore, is not limited to the embodiments set forth herein, but
is limited only by the scope of the attached claims, including the
full range of equivalency to which each element thereof is
entitled.
* * * * *