BACKGROUND

[0001] This disclosure relates to pipeline tools designed to block product flow during pipeline maintenance and repair operations. In particular, this disclosure relates to seals that are used on the plugging heads or modules of these types of tools when having to span a large gap between the seal in its unset and set positions. For purposes of this application, a large gap means a seal gap extrusion where the ratio of pipeline inner diameter to tool outer diameter is greater than approximately 1.10.

[0002] Prior art large-gap seals can exhibit high strain or strain gradients when activated to the set position and then forced inward radially to seal against its unset inner diameter. The absolute strain levels in the seal may or may not be of major significance to damage of the elastomer. Where structural segments are used to reinforce the seal, there is a potential danger of segments flipping or experiencing permanent deformation at high isolation pressures that would cause jamming of the segments and prevent the seal from retracting. Point loads of the structural segments to the inner pipe wall can introduce high stress peaks that may cause damage to the pipe as well as difficulties when trying to achieve compliance with the pipeline standards.

[0003] Creep crack growth can be a primary cause of failure when the seal is under load for extended periods of time. The complexity of the seal side profile may be directly related to the risk of crack initiation. The selection of a more “exotic” material that is not susceptible to creep crack growth is expensive due to low volume and potential requirement for unconventional manufacturing methods. The complexity of the seal side profile directly affects manufacturing cost. Additionally, in large-gap seal designs, the required piston stroke is large, making the tool long and therefore less piggable. The length of the tool reduces the benefits of the high expansion sealing capability. SUMMARY

[0004] Embodiments of an isolation tool of this disclosure are intended for intrusive (hot tap) applications and can span a large gap by way of “T-bone” or T-shaped” seal, with pressure heads on each side of the lower profile of the seal that act as support and prevent extrusion of the seal ID. Structural support elements that overlap one another provide support to the upper profile of the seal. Embodiments may also be arranged for non-intrusive applications in which the tool is pigged into a predtermined location within the pipeline.

[0005] Because the pressure heads located on each side of the lower profile of the seal have a diameter (radial height) less than that of the sealing element when the sealing element is in its unset position, this disclosure sometimes refers to the heads as “mini” pressure heads. The heads are also smaller in size than the angle plates that apply pressure to the seal through the structural elements and the mini-pressure heads.

[0006] The structural elements are overlapping structural elements that act like an iris. The structural elements eliminate the use of gap segments like those used in the prior art. See e.g. US 10,436,372 B2 to Bjorsvik et al, the contents of which are incorpoated by reference herein. This arrangement provides more options to seal around a primary seal such as, for example, a seal on a pressure head or bowl side.

[0007] For purposes of this disclosure, a large gap means a seal gap extrusion where the ratio of pipeline inner diameter to tool outer diameter is greater than approximately 1.10 e.g. 10% radial expansion).

[0008] Advantages of the embodiments of this disclosure include: a) Elimination or reduction of the risk of elastomer tearing; b) Allowing for control of the amount of seal squeeze and thus the seal contact pressure; c) Elimination of tilting of supporting segments; d) Simplifying the side profile of the seal compared to prior art large gap seal designs; e) Elimination of the need for “exotic” materials for the seal and reduce the cost of manufacturing; f) Allowing for size scaling; g) Allowing for low- and high-pressure isolations; h) Reduction in the amount of required piston stroke (compared to prior art designs) and therefore shorter overall length of the tool; i ) Elimination of the need for a secondary sealing head, a primary (high pressure side) sealing head being sufficient; j) Allowing sealing of large gaps, including gaps above 20 % radial expansion.

[009] Embodiments of this disclosure may be used in a pipeline isolation tool like that disclosed in US Patent No. 10,989,347 to McKone et al. (“McKone”), the content of which is incorporated by reference herein. The tool, for example, may include a pair of plugging heads, one being on the higher pressure side of the tool and serving as the primary seal, the other being on the lower pressure side of the seal and serving as the secondary seal. The tool, therefore, defines two independent sealing systems and two independent locking systems. In some embodiments of the tool, a single plugging head is used.

[0010] Regardless of whether a single plugging head or a pair of plugging heads is used, in some embodiments the hydraulically actuated piston is encased in a hydraulic cylinder formed at least in part by each of the two pressure heads. The cylinder head may be formed by an opposing pressure head of that forming the cylinder body.

[0011] A pipeline isolation tool of this disclosure includes a sealing element having an expanding, reusable seal wherein one seal may be used for a wide range of pipe wall thickness of the same nominal size. The seal can be self-energizing, its actuating force being in a same direction as a force from isolation pressure.

[0012] The structural segments of this disclosure allow for a larger range of extrusion with higher pressure retention capabilities. The plugging head may use a hydraulically activated piston and cylinder arrangement to compress the seal axially which, in turn, expands the seal radially for sealing against the pipe wall. The structural segments slide radially with the seal, maintaining a degree of overlap with one another and supporting the extruded rubber against the differential pressure.

[0013] The tool may include some machining and assembly methods to deliver hydraulic fluid from a location outside the excavation, to the jackscrew, connect through multiple components and ultimate control double acting pistons in the plugging heads. In some embodiments, the tool includes a control bar that contains a hydraulic transfer sleeve and manifold. The manifold is arranged for connection to external fluid lines, the sleeve providing the fluid to the inside of the tool. Transfer pins may be used to transfer fluid between components. In embodiments, the end of the piston may include trapezoidal shaped threads that accommodate variable spacing between components and require less precision in their placement during assembly. Spacing between the components may be off by up to one full turn and still accommodated.

[0014] Some embodiments of the tool include an tool of this disclosure include an arcuate-shaped bumper that makes contact with the ID of the pipe to distribute forces experienced by the tool back into the pipe when sealing against the pipe. The bumper may be cam-actuated, for example, connected to an arm that moves into contact with the ID of the pipe as the tool enters the pipe and moves into a position ready for sealing against the ID. In other embodiments, the cam-actuated arm arrangement may be replaced by a bumper connected to an arm or body that is hydraulically actuated. [0015] An additional feature in some embodiments is a urethane disc mounted on the front of the tool that pushes chips away from sealing surfaces. This “chip sweep” makes it easier to form a seal. The sweep may be replaced or supplemented by a nozzle that injects fluid ahead of the tool. [0016] The tool may be arranged as an intrusive tool. It may also be arranged as a non-intrusive tool, including gripping means and an hydraulic actuation cylinder in communication with the sealing and gripping means.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a schematic cross-section of a large-gap seal of this disclosure.

[0018] FIG. 2 is a schematic cross-section of the seal illustrating key dimensions.

[0019] FIG. 3 A shows equivalent strain at activation. This linear FEA is sufficient for a qualitative assessment of embodiments of this disclosure. The strain field is uniform across the cross-section and reaches up to 50 % (hoop component of the strain is dominant). The maximum reported strains are located at the boundary between the structural (interlocking) segments, however, because of non-optimized geometry these values can be disregarded for other embodiments. A plurality of O-rings provide sealing between an axially oriented surface of the pressure head and the guide.

[0020] FIG. 3B is a cut-away perspective view of the seal of FIG. 3 A.

[0021] FIG. 4A shows an embodiment of this disclosure that makes use of a mini pressure head to completely prevent extrusion of the seal ID. The seal is shown in its unset position. A pair of O- rings provide sealing between an axially oriented surface of the pressure head and the guide.

[0022] FIG. 4B is the embodiment of FIG. 4A as it transitions to the set position.

[0023] FIG. 5 is a screenshot from an FEA animation showing the structural elements when the seal is in its unset position.

[0024] FIG. 6 is a screenshot from an FEA animation showing the structural elements when the seal is in its set position. [0025] FIG. 7 is an isometric view of a large-gap seal of this disclosure when in a test fixture.

[0026] FIG. 8 is a cross-section view of the seal of FIG. 7.

[0027] FIG. 9 is a front elevation view of an embodiment of a structural element of this disclosure.

[0028] FIG. 10 is a top plan view of the element of FIG. 9.

[0029] FIG. 11 is a bottom plan view of the element of FIG. 9.

[0030] FIG. 12 is a rear elevation view of the element of FIG. 9.

[0031] FIG. 13 is a left side elevation view of the element of FIG. 9.

[0032] FIG. 14 is a right side elevation view of the element of FIG. 9.

[0033] FIG. 15 is an isometric view of an embodiment of a T-bone-shaped seal of this disclosure.

[0034] FIG. 16 is a cross-section view of the seal of FIG. 15.

[0035] FIG. 17 is a front elevation view of an embodiment of an angle plate of this disclosure. In some embodiments, the plate includes angled surfaces in a range of 10° to 20°, there being subranges and discrete values within this broader range.

[0036] FIG. 18 is a right side elevation view of the plate of FIG. 17.

[0037] FIG. 19 is an isometric view of an embodiment of a mini pressure head of this disclosure.

[0038] FIG. 20 is a cross-section view of the mini-pressure head of FIG. 19.

[0039] FIG. 21 is an isometric view of an embodiment of a mini pressure head of this disclosure and more suitable for higher pressures than the head of FIG. 19.

[0040] FIG. 22 is a cross-section view of the mini-pressure head of FIG. 21.

[0041] FIG. 23 is an isometric, exploded view of an isolation tool of this disclosure. The tool may include a pair of bumpers on the primary plugging head, the bumpers making contact with a pipe wall (lateral access) cutout when the tool is inserted and retracted into the main pipeline.

[0042] FIG. 24A is an embodiment of an isolation tool of this disclosure including an arm with an arcuate-shaped bumper that makes contact with the ID of the pipe to distribute forces experienced by the tool back into the pipe when sealing against the pipe. Only one plugging head is shown for purpose of illustration. The arm is shown in its set or fully deployed position with the sealing element in its unset position. The arm may be connected to the control bar and moved into position as the tool enters the pipeline or it may be hydraulically actuated. Once in its set position, the sealing element may be deployed.

[0043] FIG. 24B is a top view of the isolation tool of FIG. 24 A.

[0044] FIG. 25 A is side view of the arm of FIG. 24A when in an unset position.

[0045] FIG. 25B is a side view of the arm of FIG. 24 A when in a set or fully deployed position.

[0046] FIG. 25C is a top view of the arm of FIG. 24A (unset position).

[0047] FIG. 25D is a top view of the arm of FIG. 24A (set position).

[0048] FIG. 26A is an isometric view of an embodiment of a transfer pin of this disclosure. The transfer pin helps continue the fluid circuit between adjacent components like the control bar and yoke or the yoke and plugging head.

[0049] FIG. 26B is a cross-section view of the transfer pin of FIG. 26A. The transfer pin is threaded along the length opposite that of the o-ring grooves.

[0050] FIG. 27A is a cross-section view illustrating the transfer pin located along a hydraulic fluid passageway between two adjacent components of the isolation tool.

[0051] FIG. 27B is a view of the transfer pin and an anti-rotation pin on a lower pressure side of the tool between the secondary hinge and secondary piston.

[0052] FIG. 28 A is cross-section view of an embodiment of a spring-loaded anti-rotation pin of this disclosure located on the higher pressure side, with the stem in a retracted (minimum stroke) position. The spring may be a wave spring.

[0053] FIG. 28B is cross-section view of the spring-loaded anti-rotation pin of FIG. 28A with the stem in an extended (maximum stroke) position. [0054] FIG. 29 is an embodiment of an actuator bar for use with isolation tools of this disclosure. The actuator includes an hydraulic transfer sleeve (FIG. 32) that contains a manifold (FIG. 33) that passes hydraulic fluid from outside of the pipe into the isolation tool.

[0055] FIG. 30 is a cross-section view of an upper end of the actuator bar indicated by section 30 of FIG. 29.

[0056] FIG. 31 is a cross-section view of a portion of the upper end of the actuator bar indicated by section 31 of FIG. 30.

[0057] FIG. 32 is an embodiment of a hydraulic transfer sleeve of FIGS. 30 & 31.

[0058] FIG. 33 is an embodiment of the manifold block of FIGS. 30 & 31.

[0059] FIG. 34 is an embodiment of a plugging head of this disclosure with a hydraulic cylinder formed at least in part by each of the two pressure heads. The cylinder head may be formed by an opposing pressure head of that forming the cylinder body. Arranging the hydraulic cylinder in this way provides for a shorter overall tool length.

[0060] FIG. 35 is an embodiment of the hydraulic cylinder of FIG. 34 integrated into a high pressure plugging head. Use of the hydraulic cylinder is not limited to the T-shaped seal of this disclosure and may be used with other circumferential seal designs.

[0061] FIG. 36 is an embodiment of a non-intrusive arrangement of the pipeline isolation tool. The tool includes gripping means. Sealing cups or discs of a kind known in the art may be arranged about the tool body to center the tool in the pipe and help propel it forward under differential pressure. Means known in the art may also be used to arrange the tool as part of a plugging train. [0062] FIG. 37 is an embodiment of a piston and pressure head assembly of this disclosure. The piston includes trapezoidal threads at each end. The threads accommodate variable spacing between the piston and components to which it is connected such that the spacing can be off a much as one full thread turn. [0063] Elements and Numbering used in the Drawings and Description

10 Pipeline isolation tool 102 Inner angle surface

20 Pipe 110 Angle plate

22 Pipe wall 112 Inner angle surface

30 Seal 114 Face surface

32 First side 210 First plugging head

34 Second side 212 Carrier

36 Lower seal profile 214 Yoke

37 Lower end 216 Yoke pin

38 Upper seal profile 218 Nose

40 Pressure head 220 Second plugging head

41 Inner surface 222 Upper end

42 Outer surface 230 Control bar

43 Angled surface 231 Lower end

44 Upper end 232 Transfer sleeve

45 Lower end 234 Ports

47 Recess 236 Manifold

50 Pressure head 238 Yoke

51 Inner surface 240 Yoke pin

52 Outer surface 242 Bumpers

53 Angled surface 250 Sweep

54 Upper end 260 Arm

55 Lower end 262 Bumper

56 Axially oriented surface 264 Distal end

57 Recess 266 Linkage

58 Lower face surface 268 Proximal end

59 O-ring 270 End

60 Structural elements 272 End

62 Upper end 276 Cam surface

64 Inner face 278 Cam

66 Outer face 290 Transfer pin Overlap 292 Passageway

Concave area 294 Threaded length

Second outer diameter 296 Hex-shaped head

First outer diameter 298 O-ring groove / O-ring

Structural elements 300 Anti-rotation pin

Upper end 302 Spring

Inner face 304 Stem

Outer face 306 Piston

Overlap 308 Hydraulic cylinder

Concave area 310 Deactivation volume

First outer diameter 312 Activation volume

Second outer diameter 314 Trapezoidal threads

Angle plate 320 Gripping means

DETAILED DESCRIPTION

[0064] Referring now to the drawing figures, embodiments of a pipeline isolation tool 10 are shown and described. Pipeline isolation tool 10 is received in pipe 20. Pipe 20 defines pipe wall 22. Pipeline isolation tool 10 includes circumferential seal 30. Circumferential seal 30 has first side 32 and second side 34. Seal 30 is expandable between an unset position and a set position. Seal 30 is configured to sealable engage pipe wall 22 in the set position. When in the set and unset positions, seal 30 defines a T-shaped cross section defining a radially v oriented lower seal profile 36 and a horizontally oriented upper seal profile 38. In some embodiments, radially oriented lower seal profile 36 is smaller in cross section than axially oriented upper seal profile 38.

[0065] For purposes of this disclosure, the radial direction and axial direction are relative to the seal 30. For example, when tool 10 is set in a horizontally oriented pipe, the radial direction is vertical (z-axis) and the axial direction is horizontal (y-axis). When tool 10 is set in a vertically oriented pipe, the radial direction is horizontal (y-axis) and the axial direction is vertical (z-axis). [0066] Circumferential pressure heads 40, 50are located on each side 32, 34 of the seal 30. First circumferential pressure head 40 is located adjacent first side 32 of radially oriented lower seal profile 36. First circumferential pressure head 40 defines outer surface 42. Second circumferential pressure head 50 is located adjacent second side 34 of radially oriented lower seal profile 36.

Second circumferential pressure head 50 defines outer surface 52.

[0067] A plurality of first structural) elements 60 are located adjacent first side 32 of seal 30. Each of plurality of first structural elements 60 have an upper end 62, an inner face 64, and an outer face 66. Each of plurality of first structural elements 60 define overlap 68 (see e.g., FIG. 5) with at least a portion of an adjacent first structural element 60. Each of plurality of first structural elements 60 defines concave area 70 proximate to upper end 62 for receiving a portion of axially oriented upper seal profile 38 of seal 30. Inner face 64 of plurality of first structural elements 60 contacts outer surface 42 of first circumferential pressure head 40.

[0068] An amount of overlap 68 of adjacent ones of plurality of first structural elements 60 decreases as seal 30 moves from the unset position (see e.g., FIGS. 1, 2, 4) to the set position (see e.g., FIG. 3A). An amount of overlap 68 of adjacent ones of plurality of first structural elements 60 increases as seal 30 moves from the set position (minimum or lesser overlap) to the unset position (maximum or greater overlap). Therefore, the plurality of first structural elements 60 define an first outer diameter 74 in the unset position (see FIG. 5) and define a second outer diameter 72 in the set position (see FIG. 5). The second outer diameter 72 is greater than the first outer diameter 74.

[0069] A plurality of second structural (interlocking) elements 80 is located on second side 34 of seal 30. Each of the plurality of second structural elements 80 have an upper end 82, an inner face 84, and an outer face 86. Each of the plurality of second structural elements 80 define an overlap 88 (see e.g., FIGS. 5, 6 & 13) with at least a portion of an adjacent second structural element 80. Each of the plurality of second structural elements 80 define a concave area 90 proximate to upper end 82 for receiving a portion of axially oriented upper seal profile 38 of seal 30. Inner face 84 of the plurality of second structural elements 80 contact outer surface 52 of second circumferential pressure head 50.

[0070] An amount of overlap 88 of adjacent ones of the plurality of second structural elements 80 decrease as seal 30 moves from the unset position to the set position. An amount of overlap 88 of adjacent ones of the plurality of second structural elements 80 increases as seal 30 moves from the set position (minimum or lesser overlap) to the unset position (maximum or greater overlap). Therefore, the plurality of second structural elements 80 define a first outer diameter 92 (see e.g., FIGS. 3 A, 6) in the set position and define a second outer diameter 94 (see e.g., FIGS. 1, 2, 4, 5) in the unset position. The second outer diameter 94 is greater than the first outer diameter 92. [0071] The first and second structural elements 60, 80 engage with respetive circumferential angle plates 100, 110. First circumferential angle plate 100 defines an inner angle surface 102. Inner angle surface 102 is in contact with outer face 66 of each of the plurality of first structural elements 60. Second circumferential angle plate 110 defines inner angle surface 112. Inner angle surface 112 is in contact with outer face 86 of each of the plurality of second structural elements 80. The angle plates 100, 110 function as pressure heads, applying pressure to the structural elements as well as the mini-pressure heads 40, 50.

[0072] The plates 100, 110 may span the radial distance from the lower end 45, 55 of the pressure heads 40, 50 to an upper end 62, 82 of the structural elements 60, 80 (and therefore are larger size pressure heads than the pressure heads 40, 50). In embodiments, the plates 100, 110 are not mirror images of another, nor are the pressure heads 40, 50.

[0073] Embodiments of disclosure further include a “T-bone” or T-shaped” seal 30 in crosssection, see FIGS. 1, 3, 4 A, & 15- 16. the sealing element 30 having an upper profile 38 and a lower profile 36, the lower profile 36. The two profiles 36, 38 may be different in shape from one another. In some embodiments, the lower profile 36 is narrower in cross-section than the upperprofile 38. A circumferential pressure head 40, 50 is located on each side of, and in contact with, the lower profile 36 of the sealing element 30. A plurality of structural elements 60, 80 are arranged about the pressure heads 40, 50, each structural element 60, 80 overlapping at least a portion of an adjacent structural element 60, 80.

[0074] In embodiments, the pair of circumferential angle plates 100, 110 and pair of circumferential pressure heads 40, 50 may be arranged such that, as the circumferential seal 30 moves from the unset position to the set position, the pair of circumferential angle plates 100, 110 apply pressure to the plurality of structural elements 60, 80 prior to the pair of circumferential pressure heads 40, 50 applying pressure to the radially oriented lower profile 36.

[0075] The structural elements 60, 80 include a concavity 70, 90 at an upper end 62, 82, into which a portion of the upper profile 38 of the sealing element 30 resides, and an inner face surface 64, 84 in contact with an outer surface 42, 52 of the pressure head 40, 50. The amount of overlap 68, 88 between the adjacent structural elements 60, 80 decrease as the sealing element 30 moves from an unset to a set position, the amount of overlap 68, 88 increasing as the sealing element 30 moves from the set to the unset position. Because the amount of overlap 68, 88 increases and decreases, the structural elements 60, 80 expand between a first size and a second size. A circumferential angle plate 100, 110 includes an inner angled surface 102, 112 that contacts an outer face surface 66, 86 of the structural element 60, 80.

[0076] The radially oriented lower seal profile 36 may be smaller in cross-section than the axially oriented upper profile 38 of the seal 30. However, the smaller cross-section is not important for the seal 30 to work as intended. The mini pressure heads 40, 50, see FIGS. 19-22, on each side 32, 34 of the lower seal profile 36 act as supporting structures and prevent extrusion of the seal ID.

[0077] In the unset position, the lower profile 36 resides between the mini pressure heads 40, 50, with the upper profile 38 being entirely above upper end 44, 54 of the heads 40, 50. The seal 30 expands towards the pipe 20 in near pure “natural” (hoop) stretch in order to achieve a uniform strain distribution along the entire seal cross-section.

[0078] Note that in some embodiments the lower end 37 of the seal 30 does not contact an opposing axially oriented surface 56 of the pressure head 50, and the radial distance between the two increases as the seal 30 moves between the unset and set positions (compare FIG. 4A (in unset position) to FIGS. 3A (set position) and 4B (moving to set postion)). The lower end 37 is spaced a first radial distance from the axially oriented surface 56 when the circumferential seal 30 is in the unset position and a second radial distance greater than that of the first when the seal 30 is in the set position, the first radial distance being greater than zero. Because of this armagement, and by way of a non-limiting example, the seal 30 may expand to about 60% to 70% of the radial area available.

[0079] As contact with the pipe ID 22 occurs, the mini pressure heads 40, 50 get compressed towards the seal 30 and act across a large cross-section in order to distribute the load from the isolation pressure. See FIGS. 4A & 4B. Unlike the outer surface 42, 52 of the pressure heads 40, 50, which have a constant slope, the inner surface 41, 51 of the pressure heads 40, 50 does not. In some embodiments, the inner surfaces 41, 51 may include a plurality of surfaces 43A-C, 53 A-C oriented at different angles such that a recessed area 47 is formed (thereby providing greater axial distance between the heads 40, 50 at the upper end 44, 54, than at the lower end 45, 55). For example, surface 43 A, 53 A may be vertical, surface 43B, 53B may then angle toward outer surface 42, 52, and surface 43C, 53C may be vertical or slighlty off vertical, angling toward the outer surface 42, 52.

[0080] When transitioning to the set postion, and when in the set position, a portion of the lower profile 38 may reside within the recess 47 — that is, in contact with surfaces 43B-C, 53B-C but not 43A, 53A -- with another portion of the lower profile residing entirely above the upper ends 44, 54 of the pressure heads 40, 50. A pair of O-rings 59 located between a lower face surface 58 of pressure head 50 and an opposing face surface 114 of the angle plate 110 provide sealing between pressure head 50 and angle plate 110. The o-rings 59 do not expand.

[0081] Referring to FIG. 2, the main dimensions “A” and “B” of T-shaped seal 30, together with distance “D” between the structural segments 60, 80, dictate when contact between the elastomer and steel components get established. In embodiments, the mini pressure heads 40, 50 do not start squeezing the seal 30 immediately but do so later in the activation cycle in order to allow for building a uniform strain field within the seal 30. Dimensions “A”, “B” and “C” are predetermined to account for the design expansion gap and can be optimized to accommodate one or more pipe IDs.. Note that where two or more pipe IDs are designed for, the seal 30 would have multiple set positions, that is, one for each pipe ID. For example, , the circumferential seal 30 can have a first set position and a second set position, the first set position being for a first pipe diameter and second set position being for a second pipe diameter greater than that of the first pipe diameter. Thickness “C” should (in general) be sized to bring the segments 60, 80 together as much as possible and prevent the rubber seal 30 from extruding inward into the cavity between the mini pressure heads 40, 50. Thickness “C” may be smaller than that of “B”. In some embodiments, the overall height of the seal 30 (in the radial direction when unset) is less than the radial distance “G” (see e.g. FIGS. 3 to 4B). Distance “E” also helps with the preventing extrusion; making sure the seal 30 has enough support on the segments 60, 80, which will reduce the risk of extruding the seal 30 radially inwards. The pressure heads 40, 50 include a radius “F” at their upper end where the seal 30 transitions between its lower and upper profiles 36, 38.

[0082] ID extrusion of seal 30 at high pressure can be a risk. FIG. 3 shows an embodiment in which the ID extrusion of seal 30 is limited, but possible. Such a design is considered for low pressure applications, and can be optimized as stated above by manipulating dimensions “C”, “D” and “E” as well as “G.”. FIGS. 4A and 4B shows an embodiment that prevents extrusion of the ID of seal 30 completely. See also FIGS. 21 & 22. The lower profile 36 of the seal 30 does not contact an upper axially oriented surface 51 of pressure head 50. The lower end 37 of the profile 36 may be narrower in cross-section than the middle and upper portions of the profile 36. In some embodiments, the cross-section of toward the lower end 37 is semi-hexagonal in shape. When the seal 30 gets activated, the mini pressure heads 40, 50 squeeze the ID extension of seal 30 and also make contact. This introduces an adjustable reinforcing effect that can be tailored for high- pressure isolations.

[0083] Furthermore, a high Shore rubber can be molded to the ID of the seal 30 in order to achieve a hard seal that would prevent radial extrusion (with a lower Shore rubber on the OD of the seal). The contact between the mini pressure heads 40, 50 and the seal 30 can also be designed as a high- friction contact to help minimize this effect. In some embodiments, a higher Shore rubber is used on the upper comers of the seal 30 than in other areas of the seal 30.

[0084] Increased stress and jamming of the movable mini pressure heads 40, 50 is another risk that can also be addressed by design features, such as increasing material thickness, ensuring a low friction surface and proper gap tolerance between the mini pressure heads 40, 50, angle features angle plates 100, 110.

[0085] A large-gap seal 30 of this disclosure expands radially with low force, remains relatively unstrained from the axial direction during setting, and introduces a reinforcing effect to supporting segments that prevents them from tilting at large expansion gaps. Embodiments of this disclosure expand radially by 20% or more to engage the pipe wall 22 due to the reinforcing effect of segments 60, 80 and no need to extrude the seal 30 radially inwards. The seal 30 is also independent of the isolation pressure magnitude with no ID of seal 30 extrusion. The seal 30 also is highly customizable in that in can be optimized for a variety of expansion gaps and isolation pressures by manipulating angles, thicknesses and heights of the segments 60, 80 and T-bone shaped seal 30.

[0086] Referring now to FIGS. 23 & 35, embodiments of an isolation tool 10 of this disclosure may include a first and second plugging head 210, 220 in pivotal relation to one another. When inserted into pipe 20 in a same direction as pipeline product flow, plugging head 210 serves as the primary plugging head (on the higher pressure side of the tool 10, there being a pressure differential across the head 210) and plugging head 220 serves as the secondary plugging head (on the lower pressure side of the tool, there being a pressure differential across the head 220). Each plugging head 210, 220 includes seal 30, pressure heads 40, 50, and segments 60, 80 as previously described. Any pipeline product leaking past the first head 210 is prevented from passing the second head 220. The tool 10, therefore, defines a double barrier or double block because it has two independent sealing systems and two independent locking systems. Bleed or venting of pipeline product can be provided between the heads 210, 220 when in their sealing positions.

[0087] When arranged as an intrusive tool, plugging head 210 is pivotally connected by a yoke 214 to a carrier 212. Yoke 214 rotates about a yoke pin 216 contained within a yoke mount 218 connected to carrier 212. Plugging head 220, which may be the secondary plugging head (on the low pressure side of tool 10), is connected to plugging head 210 by a yoke 238 that rotates about a yoke pin 240. Yoke 238 may include a pair of bumpers 242 that help prevent yoke 214 and plugging head 210 from becoming entrapped in the access connection to pipe 20 during installation into, and removal from, the pipe 20.

[0088] In embodiments, the tool 10 travels downward through a lateral access connection and travels into the pipe 20 in a way similar to that described in US 7,841,364 B2 to Yeazel et al. (“Yeazel”), the content of which is incorporated by reference herein. Venting between the heads 210, 220 may occur by way of a bleed port. See e.g. Yeazel. The tool 10 also may be configured as a non-intrusive tool as shown in FIG. 36 and include gripping means 320 . Sealing cups or discs of a kind known in the art may be arranged about the tool body to center the tool 10 in the pipe 20 and help propel the tool 10 forward under differential pressure. Means known in the art may also be used to arrange the tool 10 as part of a plugging train. Each plugging head 210, 220 may be a separate module of the plugging train. [0089] Referring to FIGS. 29 to 33, when configured or arranged as an intrusive tool, carrier 212 is connected at its upper end 222 to a control bar 230. The control bar 230 is used, along with control bar head 212 and yokes 214, 238, to radially insert, rotate, and position the tool 10 into a final sealing position within the pipe 20. The control bar 230 also supplies hydraulic fluid to each plugging head 210, 220. In some embodiments, control bar head 212 may be the same or similar to that disclosed in US Patent No. 10,989,347 to McKone et al.

[0090] Some embodiments of the tool 10 may include a control bar 230 that includes an hydraulic transfer sleeve 232 (FIG. 32) that contains a manifold 236 (FIG. 33) that passes hydraulic fluid from outside of the pipe 20 into the isolation tool 10. The hydraulic transfer sleeve 232 includes a set of ports 234 that communicate with a complementary set of ports 238 of the manifold 236. The ports 238 then communicate with external fluid lines.

[0091] In embodiments, the leading plugging head 210 or 220 during insertion into pipe 20, may include a chip sweep 250. The chips being swept downstream of the tool 10 by sweep 250 are typically the result of a hot tap operation. Th chips may also include other pipeline debris that could interfere with seal 30 when engaging the pipe wall 22. In some embodiments, the sweep 250 may be a urethane disc. In other embodiments, sweep 250 may be supplemented (or replaced) by a nozzle arranged to inject an inert gas such as nitrogen or a liquid, or a pipeline product, ahead of the sweep 250 or tool 10. The nozzle may include ports arranged to draw the gas or liquid into the nozzle by way of venturi effect as the tool 10 is being inserted into the pipe 20.

[0092] Referring now to FIGS. 24A to 25D, in some embodiments tool 10 may include an arcuateshaped bumper 262 that engages with the pipe wall 22 and distribute forces experienced by the tool 10 to the pipe 20. The bumper 262 may be deployed through mechanical means such as an arm 260 or extended and retracted by way of an hydraulic cylinder The arcuate-shaped bumper 262 is moveable between a first position and a second position. When in the first position, the arcuate-shaped bumper 262 is inward of a sealing diameter of the circumferential seal 30. When in the second position, the arcuate-shaped bumper 262 extends to a sealing diameter of the circumferential seal 30.

[0093] In one embodiment, the arm 260 is fixed at a lower end 231 of the control bar 230. The arm 260 is arranged to move between a first (non-deployed) position and a second (fully deployed) position as the tool 10 is positioned within the pipe 20. The arm 260 is curved between its two ends 264, 268 and includes an arcuate-shaped bumper 262 at its upper (distal) end 264. The bumper 262 is shaped complementary to the ID of the pipe 20. A linkage 266 is connected at one end 270 to the lower (proximal) end 268 of the arm 260 and is fixed at another end 272 to the yoke 214 or control bar 230. The lower end 268 of the arm 260 includes a cam surface 276 and the end 272 of the-linkage 266 includes a cam 278.

[0094] As the yoke 214 travels into the pipeline 20, the yoke 214 pushes the cam 278 and the arm 260 moves between the first and second positions and, when in the second position, the bumper 262 contacts the inner diameter of the pipeline 20. The forces experienced by the tool 10 are distributed to the pipe 20. When in the second position, the arm 260 may overlap a portion of the plugging head 210 but is rearward of the seal 30.

[0095] The arm 260 may be sized and arranged so that contact with the ID of the pipe 20 occurs within the length of the pipe 20 that is enclosed by the fitting located on the outside of the pipe 20. The fitting is typically a saddle branch fitting of a kind known in the art for lateral access connections used in hot tapping operations.

[0096] Referring now to FIGS. 26 A to 27B, transfer pins 290 including a hydraulic passageway 292 may be used between adjacent components of the tool 10 to avoid external hydraulic lines and deliver hydraulic fluid to each plugging head 210, 220. For example, a transfer pin 290 can be placed between a yoke and a piston. The transfer pin 290 includes O-ring grooves 298 at one end and a threaded length 294 at another end. The threaded length 294 may be a standard metric thread. In embodiments, the transfer pin 290 may include a hex-shaped head 296 to accommodate assembly of the tool 10.

[0097] Referring to FIGS. 27B to 28B, embodiments of tool 10 may include a spring-loaded antirotation pin 300. The anti-rotation pin 300 prevents relative rotation between the nose of the plugging head 210 or 220 and the hydraulically actuated piston 306. The spring may be a wave spring 302.

[0098] During assembly of the tool 10, use of the spring 302 in connection with a stem 304 allows an assembler to grab the anti-rotation pin 300 and lock it in the unlocked position. Because the end of the stem 304 is threaded, the assembler and can secure a nut on the end of stem 304 to keep spring 302 compressed.

[0099] In embodiments, the piston 306 has threads 314 at each end, see FIG. 37, that are not clocked so the gap between the piston 306 and hinge (yoke) 214 can be as much as one whole thread pitch (e.g. a 6 mm thread allows for a gap from 0-6 mm). The threads, which may be trapezoidal threads, allow for variable gap spacing between whatever component is threading onto the piston. In this way, a gap of zero to one full turn may be accommodated in order to have the component and piston 306 clocked properly relative to one another.

[00100] In some embodiment of a plugging head 210 or 220 of this disclosure, a piston or hydraulic cylinder 308 formed, at least in part, by each of the two angle plates 100, 110. See FIGS. 34 & 35. The cylinder 308 may be arranged such that the deactivation volume 310 is greater than that of the actuation volume 312. Compared to embodiments that make use of piston 306, hydraulic cylinder 308 provides for a shorter overall tool length. The cylinder head may be formed by an opposing angle plates 100, llOof that forming the cylinder body 308. Use of the cylinder 308 is not limited to a T-shaped seal 30 but may be used with other sealing elements. For example, the cylinder 308 may be used with sealing elements the same as or similar to those disclosed by McKone et al.

[00101] While embodiments have been described, an isolation tool of this disclosure may be modified by persons of ordinary skill in the art without departing from the scope of the following claims, the elements recited in the claims being entitled to their full range of equivalents.