Patent Description:
In general, the disclosure describes a pipe isolation device for use in pipes. The pipe isolation device may be used in pipelines carrying fluids such as pressurized fluids, high or low temperature fluids, steam, or hazardous fluids.

When performing pipeline maintenance or servicing, such as during hot tapping procedures, it is necessary to provide isolation of a "live" section of pipe. One such technique is using a "double isolation-and-bleed" apparatus, also referred to as a double block-and-bleed apparatus. As the term double isolation-and-bleed is known in the art, it refers to the setting of two seals in a pipe with a bleed port located therebetween. If fluid leaks past the first seal, it is contained by the second seal and forced to exit the pipe through the bleed port. The double isolation-and-bleed pipe isolation devices known in the industry generally comprise a series of pivoting arms. Due to the challenging environment, the pivoting arms represent points of potential failure. Another technique is using a pipe isolation device having a single sealing head having a pivoting arm to provide isolation of a "live" section of pipe. <CIT>, <CIT>, <CIT> and <CIT> relate to prior art pipe isolation devices. In particular <CIT> discloses a pipe isolation device with a control bar head, first and second sealing heads each provided with a sealing element and arranged to gain access to an interior space of a pipe with a center axis defining an axial direction.

What is needed is an improved, simplified, pipe isolation device that can accommodate a wide range of pipe sizes and thicknesses, as well as a wide range of pressurized fluids.

According to the invention, a pipe isolating device according to claim <NUM> and a method of isolating a pipe according to claim <NUM> are provided.

Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It is emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or reduced for clarity of discussion. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:.

In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the disclosure may repeat reference numerals and/or letters in the various examples. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments are possible. This description is not to be taken in a limiting sense, but rather made merely for the purpose of describing general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.

As used herein, the terms "connect", "connection", "connected", "in connection with", and "connecting" are used to mean "in direct connection with" or "in connection with via one or more elements"; and the term "set" is used to mean "one element" or "more than one element". Further, the terms "couple", "coupling", "coupled", "coupled together", and "coupled with" are used to mean "directly coupled together" or "coupled together via one or more elements". As used herein, the terms "up" and "down"; "upper" and "lower"; "top" and "bottom"; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements.

The present disclosure generally relates to achieving at least one seal in a pipe. Embodiments may have multiple seals in a pipe with a depressurized zone between the seals. This increases the safety of plugging a pipe by having a back-up seal and allows for any leakage past the primary seal to be vented out the bleed port. Some embodiments of the pipe isolation device of the present disclosure achieve the multiple seals through one branch opening in the pipe so that it reduces the amount of equipment involved in safely sealing or isolating the pipe.

Embodiments of the pipe isolation device of the present disclosure may be a tool that has a first sealing head and a second sealing head and provides a means to achieve two (or more) seals inside a pipe between the sealing heads. The pressure in the space between the two seals can be bled so that one seal is a primary seal and the other is a secondary backup seal. The tool is set by traveling through a tapped hole forming a lateral access opening inside a fitting branch on the pipe and product flow can continue through this fitting if a bypass line is set up. The pipe isolation device is configured to traverse at an angle, e.g. a right angle, as the pipe isolation device moves through the lateral access opening. The pipe isolation device uses sliding engagements to move the sealing heads of the pipe isolation device forward in the pipe to position the sealing heads in an aligned orientation with one another within the pipe and along an axis of the pipe. In other words, the sealing heads enter the pipe through the lateral access opening along a first axis and then are shifted/traversed through an angle and into alignment along a second axis which is transverse, e.g. perpendicular, to the first axis. The sealing heads can be considered as being concentric in the sense that they are both aligned along the second axis when shifted to the inserted, set position.

Referring to <FIG>, an embodiment of the pipe isolation device, referenced generally as <NUM>, of the present disclosure is shown. Pipe isolation device <NUM> comprises a control bar head <NUM>, a first sealing head <NUM>, and a second sealing head <NUM>. Sealing heads <NUM>, <NUM> may each have a disk shape. Sealing heads <NUM>, <NUM> may slide relative to each other, and the first sealing head <NUM> may slide relative to the control bar head <NUM> to position the pipe isolation device <NUM> between a fully retracted position shown in <FIG> to a fully set position shown in <FIG>.

Control bar head <NUM> may be attached to a control bar of an actuator (not shown), e.g. a hydraulically powered actuator, and the pipe isolation device <NUM> may be translated through a fitting branch of a pipe in the fully retracted position, shown in <FIG>, and moved in the pipe to the fully set position, shown in <FIG>. Control bar head <NUM> is a carrier for the sealing heads <NUM>, <NUM> and is used to convey the sealing heads <NUM>, <NUM>.

Pipe isolation device <NUM> further includes a first sliding engagement <NUM> for providing a slidable engagement connection between the control bar head <NUM> and the first sealing head <NUM>, and a second sliding engagement <NUM> for providing a slidable engagement connection between the first sealing head <NUM> and the second sealing head <NUM>, see <FIG> and <FIG>. First sliding engagement <NUM> may be formed by a pair of first guide tracks <NUM>, see <FIG> and <FIG>, attached to a side of the control bar head <NUM> and the first guide members <NUM>, see <FIG>, attached to a first side of the first sealing head <NUM>. Each of the first guide members <NUM> is interconnected with one of the first guide tracks <NUM>, as shown in <FIG>, to provide for sliding engagement between the control bar head <NUM> and the first sealing head <NUM>. First guide tracks <NUM> extend along a control bar surface <NUM>. Control bar surface <NUM> is at an acute angle with respect to a vertical axis <NUM> extending through a center of the control bar head <NUM>.

In another embodiment, the first sliding engagement <NUM> may be formed by one first guide track <NUM> and one first guide member <NUM> interconnected with one another to form a sliding engagement. In another embodiment, more than two first guide tracks <NUM> and first guide members <NUM> may be used to form the first sliding engagement <NUM> interconnecting the control bar head <NUM> and the first sealing head <NUM>. In another embodiment, one or more first guide tracks <NUM> may be attached to the first sealing head <NUM>, and one or more first guide members <NUM> may be attached to the control bar head <NUM> to form the first sliding engagement <NUM> between the control bar head <NUM> and the first sealing head <NUM>.

Second sliding engagement <NUM> may be formed by a pair of second guide tracks <NUM> and second guide members <NUM>, see <FIG> and <FIG>. Second guide tracks <NUM> are attached to a second side of the first sealing head <NUM> and second guide members <NUM> are attached to an opposing first side of the second sealing head <NUM>. Each of the second guide members <NUM> is interconnected with one of the second guide tracks <NUM>, see <FIG> and <FIG>, to provide for sliding engagement between the first sealing head <NUM> and the second sealing head <NUM>. Second guide tracks <NUM> extend along an outer surface <NUM> of the first sealing head <NUM>, and second guide members <NUM> extend along an inner surface of the second sealing head <NUM> that opposes the outer surface <NUM> of the first sealing head <NUM>. Outer surface <NUM> is at an acute angle with respect to the vertical axis <NUM>.

In another embodiment, the second sliding engagement <NUM> may be formed by one second guide track <NUM> and one second guide member <NUM> interconnected with one another. In another embodiment, more than two second guide tracks <NUM> and second guide members <NUM> may be used to form the second sliding engagement <NUM> interconnecting the sealing heads <NUM>, <NUM>. In another embodiment, one or more second guide tracks <NUM> may be attached to the second sealing head <NUM> and one or more second guide members <NUM> may be attached to the first sealing head <NUM> to form the second sliding engagement <NUM> between the sealing heads <NUM>, <NUM>.

First sealing head <NUM> has a first seal element <NUM> and the second sealing head <NUM> has a second seal element <NUM>, see <FIG>. First seal element <NUM> extends around a main body of the first sealing head <NUM> and the second seal element <NUM> extends around a main body of the second sealing head <NUM> to form circumferential seal elements. Seal elements <NUM>, <NUM> may be made from elastomeric materials. First seal element <NUM> is disposed along a first outer perimeter of the first sealing head <NUM> to form the first circumferential seal element. Second seal element <NUM> is disposed along a second outer perimeter of the second sealing head <NUM> to form the second circumferential seal element. A first nose ring <NUM> may be positioned adjacent to the first seal element <NUM>, and a second nose ring <NUM> may be positioned adjacent to the second seal element <NUM>. A first retaining ring <NUM> may be positioned adjacent to the first seal element <NUM>, and a second retaining ring <NUM> may be positioned adjacent to the second seal element <NUM>, see <FIG>.

In the embodiment illustrated, first seal element <NUM> is disposed between the first nose ring <NUM> and the first retaining ring <NUM>, and the second seal element <NUM> is disposed between the second nose ring <NUM> and the second retaining ring <NUM>. Nose rings <NUM>, <NUM> and retaining rings <NUM>, <NUM> provide support to the seal elements <NUM>, <NUM> and prevent the seal elements <NUM>, <NUM> from extruding when under pressure.

Second sealing head <NUM> may have an outer surface <NUM> with a nose element <NUM> extending outwardly therefrom. One or more pads <NUM> may be attached to the sealing heads <NUM>, <NUM>. Pads <NUM> may be made of brass, iron, polymer or other material that allows for sliding of the sealing heads <NUM>, <NUM>. In the embodiment of pipe isolation device <NUM> shown in <FIG>, a pad <NUM> is attached to a bottom section of the nose element <NUM>. Sliding engagements <NUM>, <NUM> are configured so that the pad <NUM> slide along a pipe ID as the pipe isolation device <NUM> is translated through the fitting branch of the pipe from the fully retracted position, shown in <FIG>, to the fully set position, shown in <FIG>. Pads <NUM> may be referred to as a skid element or nose pad. Pad <NUM> positions the sealing heads <NUM>, <NUM> linearly along an axis of the pipe and slides along the bottom of the pipe as the pipe isolation device <NUM> moves to the fully set position. The axis of the pipe is transverse, e.g. perpendicular, to the vertical axis <NUM>. As the pipe isolation device <NUM> moves from the fully retracted position to the fully set position, the sealing heads <NUM>, <NUM> move outwardly away from the vertical axis <NUM> that extends through the control bar head <NUM>.

Referring to <FIG>, a top view of an embodiment of the pipe isolation device <NUM> in a fully retracted position is shown. <FIG> shows a cross-section at section lines <NUM>-<NUM> of the pipe isolation device <NUM> shown in <FIG>. In the example illustrated, sealing heads <NUM>, <NUM> are oriented in-line with the control bar head <NUM> when in the fully retracted position. Vertical axis <NUM> extends through the sealing heads <NUM>, <NUM> and through the center of the control bar head <NUM> and illustrates that the sealing heads <NUM>, <NUM> and the control bar head <NUM> are oriented in-line with one another when in the fully retracted position.

With reference to <FIG>, one of the first guide tracks <NUM> is shown with one of the first guide members <NUM> interlocked in the first guide track <NUM>, and one of the second guide tracks <NUM> is shown with one of the second guide members <NUM> interlocked in the second guide track <NUM>. Each first guide track <NUM> includes a first track slot <NUM> that is elongated and formed by interior walls of the elongated, first guide track <NUM>. First track slots <NUM> may have a dovetail shape, T-shape, C-shape, or other shape where the first guide members <NUM> have a corresponding dovetail shape, T-shape, C-shape, or other shape corresponding to the track slots <NUM> and the first guide members <NUM> are retained in the first track slots <NUM>.

First guide tracks <NUM> and the first guide members <NUM> define a first fixed path for the first sealing head <NUM>. First sliding engagement <NUM> is configured to permit the first sealing head <NUM> to move along the first fixed path between the first retracted position and the first set position. First sealing head <NUM> moves along the first fixed path with each of the first guide members <NUM> engaged with one of the first guide tracks <NUM> and moving in the first track slots <NUM> so that the first sealing head <NUM> moves from a first retracted position, shown in <FIG>, to a first set position, shown in <FIG>.

First guide tracks <NUM> are oriented at an acute angle with respect to the vertical axis <NUM> of the control bar head <NUM>, and the first sealing head <NUM> moves outwardly with respect to the vertical axis <NUM> as the first sealing head <NUM> moves from the first retracted position, shown in <FIG>, to the first set position, shown in <FIG>. This outward movement of the first sealing head <NUM> with respect to the vertical axis <NUM> as the first sealing head <NUM> moves from the first retracted position to the first set position allows the first sealing head <NUM> to traverse the right angle between a pipe inlet and a pipe.

Each second guide track <NUM> includes a second track slot <NUM> that is elongated and formed by interior walls of the elongated, second guide track <NUM>. Second track slots <NUM> may have a dovetail shape, T-shape, C-shape, or other shape.

Second guide members <NUM> have a corresponding dovetail shape, T-shape, C-shape, or other shape corresponding to track slots <NUM> and are retained in the second track slots <NUM>. In some embodiments, guide members <NUM>, <NUM> may include at least one load bearing roller engageable within guide tracks <NUM>, <NUM> to form the sliding engagements <NUM>, <NUM>.

Second guide tracks <NUM> and second guide members <NUM> define a second fixed path for the second sealing head <NUM>. Second sliding engagement <NUM> is configured to permit the second sealing head <NUM> to move along the second fixed path between the second retracted position and the second set position. Second sealing head <NUM> moves along the second fixed path with each of the second guide member <NUM> engaged with one of the second guide tracks <NUM> and moving in the second track slot <NUM> so that the second sealing head <NUM> moves from the second retracted position, shown in <FIG>, to the second set position, shown in <FIG>.

Second guide tracks <NUM> are oriented at an acute angle with respect to the vertical axis <NUM> of the control bar head <NUM> and the second sealing head <NUM> moves outwardly from the vertical axis <NUM> as the second sealing head <NUM> moves from the fully retracted position, shown in <FIG>, to the fully set position, shown in <FIG>. This outward movement of the second sealing head <NUM> with respect to the vertical axis <NUM> as the second sealing head <NUM> moves from the second retracted position to the second set position allows the second sealing head <NUM> to traverse the right angle between a pipe inlet and a pipe. First guide tracks <NUM> and the second guide tracks <NUM> are parallel in the embodiment shown in <FIG>.

Guide tracks <NUM>, <NUM> each include a first track stop <NUM>, that prevents the sealing heads <NUM>, <NUM> from traveling downwards in the guide tracks <NUM>, <NUM> when the pipe isolation device <NUM> is in the fully retracted position, shown in <FIG>. First track stops <NUM> block sealing heads <NUM>, <NUM> from moving downwards in the guide tracks <NUM>, <NUM> and falling off a bottom end of the guide tracks <NUM>, <NUM>. As shown in the embodiment of <FIG>, one of the first track stops <NUM> is located at a bottom section of each of the guide tracks <NUM>, <NUM> to position the sealing heads <NUM>, <NUM> in the fully retracted position.

Guide tracks <NUM>, <NUM> may each include a second track stop <NUM>, as shown in <FIG>, disposed at a top section of the guide tracks <NUM>, <NUM>. Second track stops <NUM> may be in the form of a stop block, as shown in <FIG>. Second track stops <NUM> block sealing heads <NUM>, <NUM> from moving upwards in the guide tracks <NUM>, <NUM>. Track stops <NUM>, <NUM> retain the sealing heads <NUM>, <NUM> within a selected section of the guide tracks <NUM>, <NUM>. Track stops <NUM> position the sealing heads <NUM>, <NUM> in line with one another in the fully set position and prevent the sealing heads <NUM>, <NUM> from travelling beyond and falling off a top end of the guide tracks <NUM>, <NUM>.

<FIG> shows a top view of an embodiment of the pipe isolation device <NUM> in a fully retracted position. <FIG> shows a cross-section at section lines <NUM>-<NUM> of the pipe isolation device <NUM> shown in <FIG>. Referring to <FIG>, an embodiment is shown of a locking mechanism including a first locking mechanism <NUM> for temporarily locking the first sealing head <NUM> in the first retracted position and a second locking mechanism <NUM> for temporarily locking the second sealing head <NUM> in the second retracted position. The locking mechanisms <NUM>, <NUM> lock the sealing heads <NUM>, <NUM> in the fully retracted position with the locking mechanisms <NUM>, <NUM> in a locked state as the sealing heads <NUM>, <NUM> travel through a lateral access opening of a pipe. The locking mechanisms <NUM>, <NUM> release from the locked state to an unlocked state in response to an applied force as the control bar head <NUM> is conveyed through the lateral access opening. The locking mechanisms <NUM>, <NUM> in the unlocked state permit the first sliding head <NUM> and the second sliding head <NUM> to move to the fully set position. The overall locking mechanism may be configured to lock at least one of the sealing heads <NUM>, <NUM> in the fully retracted position and to unlock at least one of the sealing heads <NUM>, <NUM> in response to an applied force.

The first locking mechanism <NUM>, as shown in <FIG>, may be formed by a first push rod <NUM> attached to the first sealing head <NUM>, a first pocket <NUM> in the first sealing head <NUM>, and a first latch <NUM> disposed in the first pocket <NUM>. In this example, first latch <NUM> is biased to engage with the first track stop <NUM> on the first guide track <NUM>. The engagement between the first latch <NUM> and the first track stop <NUM> secures the first sealing head <NUM> in the first retracted position, as shown in <FIG>, to place the first sealing head <NUM> in a first locked state. The engagement between the first latch <NUM> and the first track stop <NUM> may be a frictional engagement that secures the first sealing head <NUM> in the first locked state. In some embodiments, the engagement between the first latch <NUM> and the first track stop <NUM> may be an abutment engagement that secures the first sealing head <NUM> in the first locked state. The first locked state temporarily locks the first sealing head <NUM> in the first retracted position.

First push rod <NUM> may be moved upwards in the first sealing head <NUM> by applying a second applied force against a bottom end of the first push rod <NUM> to force a top end of the first push rod <NUM> against a top end of first latch <NUM>. First push rod <NUM> moves forward with enough force to overcome the bias of the first latch <NUM> and to depress the first latch <NUM> into the first pocket <NUM>. The bias of the first latch <NUM> may be provided by a first spring <NUM> attached to the first latch <NUM> or another biasing member that biases the first latch <NUM> out of the first pocket <NUM>. In operation, the first push rod <NUM> may be actuated when the first push rod <NUM> engages and is displaced by a bottom of a pipe as the pipe isolation device <NUM> moves from the fully retracted position to the fully set position. First locking mechanism <NUM> changes or releases to the first unlocked state in response to the second applied force meeting a second force threshold. The first locking mechanism <NUM> is placed into the first unlocked state when the first latch <NUM> is pushed into the first pocket <NUM> so that the first latch <NUM> is disengaged with the first track stop <NUM>. The disengagement between the first latch <NUM> and the first track stop <NUM> places the first sealing head <NUM> in the first unlocked state so that the first sealing head <NUM> is permitted to move from the first retracted position to the first set position.

The second locking mechanism <NUM>, as shown in <FIG>, may be formed by a second push rod <NUM> attached to the second sealing head <NUM>, a second pocket <NUM> in the second sealing head <NUM>, and a second latch <NUM> disposed in the second pocket <NUM>. In this example, second latch <NUM> is biased to engage with the second track stop <NUM> on the second sealing head <NUM>. The engagement between the second latch <NUM> and the second track stop <NUM> secures the second sealing head <NUM> in the second retracted position, as shown in <FIG>, to place the second sealing head <NUM> in a second locked state. The engagement between the second latch <NUM> and the second track stop <NUM> may be a frictional engagement that secures the second sealing head <NUM> in the second locked state. In some embodiments, the engagement between the second latch <NUM> and the second track stop <NUM> may be an abutment engagement that secures the second sealing head <NUM> in the second locked state. The second locked state temporarily locks the second sealing head <NUM> in the second retracted position.

Second push rod <NUM> may be moved upwards in the second sealing head <NUM> by applying a first applied force against a bottom end of second push rod <NUM> to force a top end of the second push rod <NUM> against a top end of second latch <NUM>. Second push rod <NUM> moves forward with enough force to overcome the bias of the second latch <NUM> and to depress the second latch <NUM> into the second pocket <NUM>. The bias of the second latch <NUM> may be provided by a second spring <NUM> attached to the second latch <NUM> or another biasing member that biases the second latch <NUM> out of the second pocket <NUM>. Springs <NUM>, <NUM> may be compression springs. In operation, the second push rod <NUM> may be actuated when the second push rod <NUM> engages and is displaced by a bottom of a pipe as the pipe isolation device <NUM> moves from the fully retracted position to the fully set position. Second locking mechanism <NUM> changes or releases to the second unlocked state in response to the first applied force being applied meeting a first force threshold. Second locking mechanism <NUM> is placed into the second unlocked state when the second latch <NUM> is pushed into the second pocket <NUM> so that the second latch stop <NUM> does not block the second latch <NUM> and the second sealing head <NUM> is permitted to move from the second retracted position to the second set position.

<FIG> shows a top view of an embodiment of the pipe isolation device <NUM> in a fully retracted position. <FIG> shows a cross-section at section lines <NUM>-<NUM> of the pipe isolation device <NUM> shown in <FIG> and further illustrates another example of the locking mechanisms <NUM>, <NUM>. In the embodiment shown in <FIG>, the first locking mechanism <NUM> may be formed by a first pin <NUM> and the second locking mechanism <NUM> is formed by a second pin <NUM>. First pin <NUM> may be a detent pin and may be disposed in the first pocket <NUM> of the first sealing head <NUM>. First spring <NUM> engages the first pin <NUM> to bias the first pin <NUM> out of the first pocket <NUM>. First pin <NUM> is biased to engage with a surface of the control bar head <NUM> when the first sealing head <NUM> is in the first retracted position to place the first sealing head <NUM> in the first locked state.

A second applied force may be applied to the first locking mechanism <NUM> to overcome the biasing force of the first spring <NUM> and to depress the first pin <NUM> in first pocket <NUM>. With the first pin <NUM> depressed in the first pocket <NUM>, the first locking mechanism <NUM> is placed in the first unlocked state and the first sealing head <NUM> may be moved from the first retracted position to the first set position. In operation, the first pin <NUM> may be actuated by the first sealing head <NUM> engaging with a bottom of a pipe and applying the second applied force as the pipe isolation device <NUM> moves from the fully retracted position to the fully set position. The first locking mechanism <NUM> is moved from the first locked state to the first unlocked state in response to the second applied force meeting the second force threshold.

The second locking mechanism, as shown in <FIG>, may be formed by the second pin <NUM> disposed in the second pocket <NUM> of the second sealing head <NUM>, and a second spring <NUM> biases the second pin <NUM> out of the second pocket <NUM>. Second pin <NUM> may be a detent pin and may be biased to engage with a surface of the first sealing head <NUM> when the second sealing head <NUM> is in the second retracted position to place the second sealing head <NUM> in the second locked state.

A first applied force may be applied to the second locking mechanism <NUM> to overcome the biasing force of the second spring <NUM> and to depress the second pin <NUM> in the second pocket <NUM>. With the second pin <NUM> depressed in the second pocket <NUM>, the second locking mechanism <NUM> is placed in the second unlocked state and the second sealing head <NUM> may be moved from the second retracted position to the second set position. In operation, the second pin <NUM> may be actuated by the second sealing head <NUM> engaging with a bottom of a pipe and applying the first applied force as the pipe isolation device <NUM> moves from the fully retracted position to the fully set position.

In some embodiments, pins <NUM> and <NUM> are formed by shear pins. A shear pin or multiple shear pins are press-fit or threaded into the sealing heads <NUM>, <NUM>. The shear pin(s) in the second sealing head <NUM> are designed to shear at a lower force than the shear pin(s) of the first sealing head <NUM> so that the second sealing head <NUM> deploys before the first sealing head <NUM> deploys. The second sealing head <NUM> deploys when the second pin(s) <NUM> shear in response to the first applied force to allow the second sealing head <NUM> to move to the second set position and the first sealing head <NUM> deploys when the first pin(s) <NUM> shear in response to the second applied force to allow the first sealing head <NUM> to move to the first set position.

Second locking mechanism <NUM> may be moved from the second locked state to the second unlocked state in response to the first applied force meeting the first force threshold. The locking mechanisms may be configured so that the second sealing head <NUM> is deployed before the first sealing head <NUM>. More specifically, the first force threshold may be less than the second force threshold so that the second sealing head <NUM> is deployed before the first sealing head <NUM> is deployed.

Referring to <FIG>, a partial, quarter-sectional view of the pipe isolation device <NUM> in the fully set position is shown to further illustrate how sliding engagements <NUM>, <NUM> provide sliding connections between the control bar head <NUM> and the first sealing head <NUM> and between the first sealing head <NUM> and the second sealing head <NUM>. One of the first guide tracks <NUM> and one of the first guide members <NUM> of the first sliding engagement <NUM> are shown interlocked and slidably connected. Likewise, one of the second guide tracks <NUM> and one of the second guide members <NUM> are shown interlocked and slidably connected. Guide tracks <NUM>, <NUM> have elongated first track slots <NUM> and second guide tracks <NUM>, as shown in <FIG>, that are dovetail-shaped, as illustrated in <FIG>. Guide members <NUM>, <NUM> are dovetail-shaped to correspond with their respective guide tracks <NUM>, <NUM>.

Referring to <FIG>, an exploded view of an embodiment of the first sealing head <NUM> is shown. First seal element <NUM> is shown separated from the body of the first sealing head <NUM> to better illustrate the first seal element <NUM>. When the first seal element <NUM> is attached to the body of the first sealing head <NUM>, the first seal element <NUM> extends around the outer perimeter of the body of the first sealing head <NUM> to form a circumferential seal for sealing a pipe. First seal element <NUM> is disposed between the first nose ring <NUM> and the first retaining ring <NUM>. First nose ring <NUM> and first backing ring <NUM> provide support to the first seal element <NUM>. First retaining ring <NUM> and first nose ring <NUM> attach to the body of the first sealing head <NUM> and may have a shape that corresponds to the first seal element <NUM>. Second seal element <NUM>, second retaining ring <NUM>, and second nose ring <NUM> for the second sealing head <NUM> may be like the first seal element <NUM> and supporting rings shown and described with respect to <FIG>.

First sealing head <NUM> has the first guide members <NUM> on one side and has on the opposite side the second guide tracks <NUM>. First guide members <NUM> have a T-shape. Second guide tracks <NUM> have first track slots <NUM> that are T-shaped. For the pipe isolation device <NUM> corresponding to the embodiment of the first sealing head <NUM> shown in <FIG>, the first guide tracks <NUM> of the control bar head <NUM> have corresponding T-shapes to interconnect with the first guide members <NUM> to provide for sliding engagement between the control bar head <NUM> and the first sealing head <NUM>. First guide tracks <NUM> extend along a control bar surface <NUM>. For the pipe isolation device <NUM> corresponding to the embodiment of the first sealing head <NUM> shown in <FIG>, the second guide members <NUM> of the second sealing head <NUM> have corresponding T-shapes to interconnect with the second guide tracks <NUM> of the first sealing head <NUM> to provide for sliding engagement between the first sealing heads <NUM>, <NUM>. First guide tracks <NUM> extend along a control bar surface <NUM>.

Referring to <FIG>, the embodiment of the pipe isolation device <NUM> of <FIG> is shown in the fully set position in a pipe <NUM> where the pipe isolation device <NUM> double blocks the pipe <NUM> using the first sealing head <NUM> and the second sealing head <NUM>. Pipe isolation device <NUM> may be positioned in the pipe <NUM> by extending the pipe isolation device <NUM> in the fully retracted position, as shown in <FIG>, into a lateral access opening <NUM> and into an interior space <NUM> of the pipe <NUM>. Vertical axis <NUM> may extend through the center of the access opening <NUM>. Pipe isolation device <NUM> is configured to translate from the fully retracted position, shown in <FIG>, to the fully set position, shown in <FIG>, as described below in more detail with respect to <FIG>.

Locking mechanisms <NUM>, <NUM> are in the unlocked state when in the fully set position. More specifically, first latch <NUM> is depressed in the first pocket <NUM> as the first sealing head <NUM> moves from the first retracted position to the first set position and the second latch <NUM> is depressed in the second pocket <NUM> as the second sealing head <NUM> is moved from second retracted position to the second set position.

Seal elements <NUM>, <NUM> seal against the interior diameter (ID) of the pipe <NUM> to double block the pipe <NUM> to form a live pipe zone <NUM>, an isolated zone <NUM>, and a zero-energy zone <NUM>. The interior diameter (ID) of the pipe <NUM> is represented in <FIG> as IDP. Live pipe zone <NUM> is on the pressurized side of the first seal element <NUM>, of the first sealing head <NUM>, the isolated zone <NUM> is between the first seal element <NUM> and the second seal element <NUM>, and zero-energy zone <NUM> is downstream of the second sealing element <NUM> of the second sealing head <NUM>. First sealing head <NUM> and the second sealing head <NUM> form a double block in the pipe <NUM>. Fluid that leaks past the first seal element <NUM> flows into the isolated zone <NUM> and pressure from the fluid in the isolated zone <NUM> is bled out of the isolated zone <NUM>. A bleed port <NUM> may extend through the pipe <NUM> to connect the isolated zone <NUM> to a bleed joint (not shown) to bleed off pressure that may form in the isolated zone <NUM>. In some embodiments, pressure from the fluid in the isolated zone <NUM> is bled out of the isolated zone <NUM> through passageways extending from the isolated zone <NUM> and through the sealing heads <NUM>, <NUM> and the control bar head <NUM>, and fluidly coupled to a component on the branch of the pipe <NUM>, such as the fitting, valve, housing, or actuator. The bleed joint may be formed by a T-joint. Joints may be used to access the interior space <NUM> of the pipe <NUM>, for example, as shown in <FIG>, a bleed joint <NUM> fluidly communicates with the isolated zone <NUM> and a joint <NUM> that fluidly communicates with the zero-energy zone <NUM>.

Referring to <FIG>, an embodiment of pipe isolation device <NUM> is shown. <FIG> shows a top view of the pipe isolation device <NUM> in the fully set position, and <FIG> shows a side view of the pipe isolation device <NUM> in the fully retracted position. <FIG> shows a cross-sectional view of the pipe isolation device <NUM> in the fully set position along section line <NUM>-<NUM> of <FIG>. Like parts of the embodiments of the pipe isolation device <NUM> are labeled with like reference numbers. In the embodiment shown in <FIG>, pads <NUM> are attached to a top section and a bottom section of sealing heads <NUM>,<NUM> to slide along internal surface of a pipe and center the sealing heads <NUM>, <NUM> in the pipe as the pipe isolation device <NUM> moves to the fully set position. Second pin <NUM> is formed by a shear pin and is shown in <FIG> after the second pin <NUM> has been sheared. First pin <NUM> is formed by a shear pin and is shown in <FIG> after the first pin has been sheared. Operation of pins <NUM>, <NUM> shown in <FIG> is described in more detail with respect to <FIG>.

Pipe isolation device <NUM> has a retracted length LR in the fully retracted position, as shown in <FIG>. When in the fully set position shown in <FIG>, first sealing head <NUM> and second sealing head <NUM> are aligned with one another to form a cylindrical shape and have a perpendicular orientation with respect to the control bar head <NUM>, as illustrated by a horizontal axis <NUM> extending through control bar head <NUM> and sealing heads <NUM>, <NUM>. Horizontal axis <NUM> extends through a center of the sealing heads <NUM>, <NUM> and is perpendicular to vertical axis <NUM> extending through the center of the control bar head <NUM>. Horizontal axis <NUM> may align with the center axis of a pipe when the pipe isolation device <NUM> is deployed in the fully set position in the pipe.

First sliding engagement <NUM> is configured so that the first sealing head <NUM> moves along the first fixed path, as depicted by first track axis <NUM>, and the second sliding engagement <NUM> is configured so that the second sealing head <NUM> moves along the second fixed path, as depicted by second track axis <NUM>, as the pipe isolation device <NUM> moves from the fully retracted position to the fully set position. The fixed paths of sliding engagements <NUM> may be formed by guide tracks <NUM>, <NUM>. The fixed paths formed by the guide tracks <NUM>, <NUM> are at an acute angle, referred to as the track angle TA, with respect to the horizontal axis <NUM> extending through the center of the sealing heads <NUM>, <NUM>, as shown by track angle TA. In some embodiments, track angle TA may be from <NUM> degrees to <NUM> degrees from the horizontal axis <NUM>, as described below: <MAT>.

Pipe isolation device <NUM> in the fully set position has a deployed length LD and a deployed height HD, as shown in <FIG>. Deployed length LD is measured from the vertical axis <NUM> extending through the center of the control bar <NUM> to the end of the second sealing head <NUM>. Deployed height HD is measured from the top to the bottom of the sealing heads <NUM>, <NUM>. In some embodiments, the deployed height HD may be measured at an outermost surface of the pads <NUM> on the bottom and top sections of the sealing heads <NUM>, <NUM>. The deployed height HD of the sealing heads <NUM>, <NUM> is approximately the interior diameter (ID) of the pipe that the pipe isolation device <NUM> may be deployed. Sliding engagements <NUM>, <NUM> provide a compact deployed length LD for the pipe isolation device <NUM>.

The compact deployed length LD helps the pipe isolation device <NUM> stay within the bounds of a fitting sleeve (not shown) that may be formed around a lateral access opening through which the pipe isolation device <NUM> is inserted when in the fully set position. Limiting the deployed length LD and staying within the bounds of a fitting sleeve helps prevent damage to the pipe due to the reaction loads of the pipe isolation device <NUM> against the pipe when the pipe is pressurized.

Pipe isolation device <NUM>, in some embodiments, is configured for a pipe having a lateral access opening that has a diameter size approximately equal to the internal diameter (ID) of the pipe being sealed, sometimes referred to as a size-on-size tap. The length of a typical fitting sleeve FSL on a pipe for a full-encirclement pipe fitting is approximately the length of the internal diameter of the pipe from the center axis of the pipe branch to one of the first sleeve ends.

The deployed length LD of the pipe isolation device <NUM> may be limited with respect to the deployed height HD of the sealing heads <NUM>, <NUM> to facilitate operation. The deployed length LD of the pipe isolation device <NUM> also may be limited with respect to the retracted length LR of the pipe isolation device <NUM>. In some embodiments, the ratio of deployed length LD of the pipe isolation device <NUM> and deployed height HD of the sealing heads <NUM>, <NUM> is in the following range: <MAT> The size of a pipe isolation device <NUM> may be selected to correspond to the internal diameter of the selected pipe that will be sealed, and accordingly, different pipe isolation devices <NUM> may have different deployed lengths LD, retracted lengths LR, and deployed heights HD depending on the internal diameter of the selected pipe to be sealed. In some embodiments, the ratio of the retracted length LR of the pipe isolation device <NUM> and the internal diameter, referred to as IDP, of the selected pipe to be sealed is in the following range: <MAT> The deployed height HD of the pipe isolation device <NUM> to be used in the selected pipe may be equal to the internal diameter IDP of the selected pipe.

An overall compact size of the pipe isolation device <NUM> may be beneficial. For example, the compact size may help with installation of the pipe isolation device <NUM> when there is limited space for installation at the location of the lateral access opening.

Referring to <FIG>, another embodiment of a pipe isolation device is shown, and is referred to as pipe isolation device <NUM>. Pipe isolation device <NUM> includes the control bar head <NUM> and a single sealing head <NUM> slidably connected to the control bar head <NUM>. Embodiments of pipe isolation device <NUM> are like pipe isolation device <NUM> but the pipe isolation device <NUM> has only one sealing head, referred to as the single sealing head <NUM>. In some embodiments, the single sealing head <NUM> may be like the second sealing head <NUM> of the pipe isolation device <NUM> with the single sealing head <NUM> slidably connected to the control bar head <NUM>. In other embodiments, the single sealing head <NUM> may be like the first sealing head <NUM> of the pipe isolation device <NUM> without the second sealing head <NUM>. Like part numbers of embodiments of the pipe isolation devices <NUM>, <NUM> are labeled with like reference numbers. Single sealing head <NUM> may slide relative to the control bar head <NUM> to position the pipe isolation device <NUM> between a first retracted position shown in <FIG> to a first set position shown in <FIG>. Pipe isolation device <NUM> is in the fully retracted position when the first sealing head <NUM> is in the first retracted position and is in the fully set position when the first sealing head <NUM> is in the first set position.

Pipe isolation device <NUM> includes the first sliding engagement <NUM> for providing a slidable engagement connection between the control bar head <NUM> and the single sealing head <NUM>, see <FIG>. First sliding engagement <NUM> of the pipe isolation device <NUM> is configured to permit the single sealing head <NUM> to move along the first fixed path between the first retracted position and the first set position. First sliding engagement <NUM> for pipe isolation device <NUM> is configured as described and illustrated in <FIG> and <FIG> with respect to the pipe isolation device <NUM>. For example, first sliding engagement <NUM> may be formed by a pair of first guide tracks <NUM>, see <FIG>, attached to a side of the control bar head <NUM> and the first guide members <NUM>, see <FIG>, attached to a first side of the single sealing head <NUM>. Each of the first guide members <NUM> is interconnected with one of the first guide tracks <NUM>, as shown in <FIG>, to provide for sliding engagement between the control bar head <NUM> and the single sealing head <NUM>. First guide tracks <NUM> extend along the control bar surface <NUM>. Control bar surface <NUM> is at an acute angle with respect to a vertical axis <NUM> extending through a center of the control bar head <NUM>. Pipe isolation device <NUM> may include different embodiments of the first sliding engagement <NUM> as previously discussed with respect to the pipe isolation device <NUM>.

Referring to <FIG>, an exploded view of an embodiment of the single sealing head <NUM> is shown. First seal element <NUM> is shown separated from the body of the single sealing head <NUM> to better illustrate the first seal element <NUM>. When the first seal element <NUM> is attached to the body of the second sealing head <NUM>, the first seal element <NUM> extends around the outer perimeter of the body of the single sealing head <NUM> to form a circumferential seal for sealing a pipe. First seal element <NUM> is disposed between the first nose ring <NUM> and the first retaining ring <NUM>. First nose ring <NUM> and first backing ring <NUM> provide support to the first seal element <NUM>. First retaining ring <NUM> and first nose ring <NUM> attach to the body of the single sealing head <NUM> and may have a shape that corresponds to the first seal element <NUM>. Single sealing head <NUM> may also be an embodiment of the second sealing head <NUM> of the pipe isolation device <NUM> shown in <FIG> and <FIG>.

Pipe isolation device <NUM> may include the first locking mechanism <NUM>. First locking mechanism <NUM> is able to lock the single sealing head <NUM> in the first retracted position, as described previously with respect to the first sealing head <NUM> and as illustrated in <FIG> and <FIG>.

In operation, the pipe isolation device <NUM> may be installed to double block the pipe <NUM>, as shown in <FIG>. Pipe isolation device <NUM> is installed in the pipe <NUM> through a lateral access opening <NUM> through a sequence of operations to position the pipe isolation device <NUM> from the fully retracted position through the lateral access opening <NUM> to the fully set position in the pipe <NUM>. Pipe isolation device <NUM> may be used in a method to isolate or block fluid pressure in a pipe <NUM>. Pipe isolation device <NUM> is configured to traverse at an angle, e.g. a right angle, as the pipe isolation device <NUM> extends through the lateral access opening <NUM> and then moves the sealing heads <NUM>, <NUM> of the pipe isolation device <NUM> forward in the pipe <NUM> to position the sealing heads <NUM>, <NUM> in line with one another and with the pipe <NUM> along an axis of pipe <NUM> which is transverse, e.g. perpendicular, to vertical axis <NUM>. Sealing heads <NUM>, <NUM> form a cylindrical shape fitting within the internal diameter of the pipe <NUM> when in the fully set position. Pipe isolation device <NUM> forms multiple seals in the pipe <NUM> in the fully set position. Pipe isolation device <NUM> is configured with the first sliding engagement <NUM> to permit the first sealing head <NUM> to slide relative to the control bar head <NUM> along a first fixed path and traverse a right angle to gain access to an interior space <NUM> of the pipe <NUM>, and the second sliding engagement <NUM> permitting the second sliding head <NUM> to slide relative to the first sealing head <NUM> along the second fixed path and traverse the right angle to gain access to the interior space <NUM> of the pipe <NUM>.

Referring to <FIG>, the pipe isolation device <NUM> is in a fully retracted position and disposed in a pipe branch <NUM> above the access opening <NUM> and a bottom pipe section <NUM> in the pipe <NUM>. An actuator <NUM> is attached to the control bar head <NUM> of the pipe isolation device <NUM>. The actuator <NUM> moves the control bar head <NUM> downwards in the pipe branch <NUM> to convey the pipe isolation device <NUM> into the lateral access opening <NUM> during the installation of the pipe isolation device <NUM>. Actuator <NUM> may include an actuator control bar <NUM> detachably connected to the control bar head <NUM>. An arrow <NUM> is shown in <FIG> to depict the downward movement of the actuator control bar <NUM> and connected pipe isolation device <NUM> through the pipe branch <NUM> and the access opening <NUM>, and into the pipe <NUM>.

In the illustrated example, pipe branch <NUM> has a pipe fitting <NUM> with a pipe sleeve <NUM> that surrounds and extends outwardly from the access opening <NUM> to a first sleeve end <NUM> and a second sleeve end <NUM>. Lateral access opening <NUM> may have a diameter equal to the internal diameter of the pipe <NUM>, and the length from the vertical axis <NUM> through the center of the pipe branch <NUM> to each sleeve end <NUM>, <NUM> may be equal to the internal diameter of the pipe <NUM>, see <FIG>. Pipe fitting <NUM> may be a full-encirclement pipe fitting that fits around the full circumference of the pipe <NUM>. A first flange <NUM> connects the pipe fitting <NUM> and a valve <NUM>. A second flange <NUM> connects the valve <NUM> and an isolation device housing <NUM>. A third flange <NUM> connects to the isolation device housing and may be used for fluid flow from the pipe <NUM> that is temporarily blocked by the pipe isolation device <NUM>. Bleed port <NUM> extends through the fitting sleeve <NUM> and the pipe <NUM> and is connected to a bleed joint <NUM>.

Pipe isolation device <NUM>, as shown in <FIG>, is in the fully retracted position at an initial stage of the installation with the sealing heads <NUM>, <NUM> in locked states to temporarily lock the sealing heads <NUM>, <NUM>. For example, first pin <NUM> and second pin <NUM> may be the locking mechanisms that lock the sealing heads <NUM>, <NUM> in the locked states. Pins <NUM>, <NUM> may be formed by shear pins that are un-sheared, as shown in <FIG> and <FIG>, and have not been activated to release the sealing heads <NUM>, <NUM> to the unlocked states.

Referring to <FIG> and <FIG>, the actuator <NUM> moves the control bar head <NUM> linearly downwards and along the vertical axis of the pipe branch <NUM> and through the pipe branch <NUM>. As the control bar head <NUM> moves downwards, the pipe isolation device <NUM> is conveyed through the lateral access opening <NUM> where the second sealing head <NUM> engages the internal wall <NUM> at the pipe bottom section <NUM> of the pipe <NUM>. Pipe isolation device <NUM> is in the fully retracted position with the sealing heads <NUM>, <NUM> in the locked state as the pipe isolation device <NUM> moves through the pipe joint <NUM> and through the lateral access opening <NUM>. Pipe isolation device <NUM> is maintained in the fully retracted position until the pipe isolation device <NUM> reaches the pipe bottom section <NUM> of the pipe <NUM>. The locking mechanisms include the first locking mechanism located between the control bar head <NUM> and the first sealing head <NUM> and the second locking mechanism located between the first sealing head <NUM> and the second sealing head <NUM>. Locking mechanisms may be formed by pins <NUM>, <NUM>.

Referring to <FIG>, when the second sealing head <NUM> engages the internal wall <NUM> of the pipe <NUM> the downward force on the control bar head <NUM> provided by actuator <NUM> results in a first applied force being applied to the second sealing head <NUM>. Second pin <NUM> formed by a shear pin shears in response to the first applied force. <FIG> shows a first portion of the second pin <NUM> in the first sealing head <NUM> and a second portion of the second pin <NUM> in the second sealing head <NUM> illustrating that the second pin <NUM> has sheared and the second sealing head <NUM> is in the unlocked state. The second locking mechanism, that may be formed by second pin <NUM>, has been released to release the second sealing head <NUM> from the second retracted position at the pipe bottom section <NUM>. When in the unlocked state, the second sealing head <NUM> is not biased in the second retracted position and is permitted to slide with respect to the first sealing head <NUM>.

The first sealing head <NUM> remains in the first locked state to remain stationary with respect to the control bar <NUM> when the second sealing head <NUM> moves from the locked state to the unlocked state. Control bar head <NUM> and first sealing head <NUM> are stationary with respect to one another and continue to move downward, as depicted by arrow <NUM>, through the lateral access opening <NUM> and towards the bottom of the pipe <NUM>. As the control bar <NUM> and first sealing head <NUM> move downwards together, the sealing heads <NUM>, <NUM> slide with respect to each other and the second sealing head <NUM> slides forward in the pipe <NUM> away from the vertical axis of the control bar head and the pipe branch <NUM>, as depicted by arrow <NUM>. Second sealing head <NUM> moves forward and outwardly from the vertical axis of the pipe branch <NUM> in the pipe <NUM> with pads <NUM> sliding on the internal surface <NUM> of the pipe <NUM>. Pads <NUM> help to center the second sealing head <NUM> in the pipe <NUM>. As the second sealing head <NUM> moves forward, the sealing heads <NUM>, <NUM> slide with respect to one another.

Referring to <FIG>, as the control bar head <NUM> moves downwards, the first sealing head <NUM> engages an internal wall <NUM> at the pipe bottom section <NUM> of the pipe <NUM>. First sealing head <NUM> is in the first retracted position and in the first locked state when the pad <NUM> on the bottom of the first sealing head <NUM> initially engages the internal wall <NUM> at the bottom of pipe <NUM> directly below the lateral access opening <NUM>.

Referring to <FIG>, when the first sealing head <NUM> engages the internal wall <NUM> of the pipe <NUM> the downward force on the control bar head <NUM> provided by actuator <NUM> results in a second applied force being applied to the first sealing head <NUM>. First pin <NUM> formed by a shear pin shears in response to the second applied force. <FIG> shows a first portion of the first pin <NUM> in the control bar head <NUM> and a second portion of the first pin <NUM> in the first sealing head <NUM> to illustrate that the first pin <NUM> has sheared and the first sealing head <NUM> is in the unlocked state. When in the unlocked state, the first sealing head <NUM> is not biased in the first retracted position and is permitted to slide with respect to the control bar head <NUM>.

Control bar head <NUM> continues to move downward, as depicted by arrow <NUM>, through the lateral access opening <NUM> and towards the bottom of the pipe <NUM>. As the control bar <NUM> moves downwards, the control bar head <NUM> and the first sealing head <NUM> slide with respect to each other and the sealing heads <NUM>, <NUM> slide forward and outwardly in the pipe <NUM> away from the vertical axis of the control bar head <NUM> and the pipe branch <NUM>, as depicted by arrow <NUM>. As sealing heads <NUM>, <NUM> move forward in the pipe <NUM>, the pads <NUM> on the sealing heads <NUM>, <NUM> slide on the internal surface <NUM> of the pipe <NUM>. Pads <NUM> help to center the sealing heads <NUM>, <NUM> in the pipe <NUM>. As the sealing heads <NUM>, <NUM> move forward, the control bar head <NUM> and the first sealing head <NUM> slide with respect to one another.

Referring to <FIG>, as the control bar head <NUM> moves downwards, the control bar head <NUM> engages the internal wall <NUM> at the bottom of the pipe <NUM> directly below the lateral access opening <NUM>. Pipe isolation device <NUM> is in the fully set position with the first sealing head <NUM> in the first set position and the second sealing head <NUM> in the second set position. First sealing head <NUM> forms a primary seal to fluid flowing in the pipe <NUM> and the second sealing head <NUM> forms a secondary seal if fluid leaks past the primary seal. Bleed port <NUM> extends through the fitting sleeve <NUM> and the pipe <NUM> to the isolated zone <NUM> located between the first seal element <NUM> and the second seal element <NUM>, see <FIG>.

Pipe isolation device <NUM> may be disposed within the bounds of the sleeve ends <NUM>, <NUM> when positioned from the fully retracted position to the fully set position. As shown in <FIG>, the sealing heads <NUM>, <NUM> together have a cylindrical shape. Pipe isolation device <NUM>, in some embodiments, is configured for a pipe having a lateral access opening <NUM> that has a diameter size approximately equal to the internal diameter of the pipe <NUM> being sealed, sometimes referred to as a size-on-size tap. A fitting sleeve length FSL may be measured from the vertical axis <NUM> extending through the center of the pipe branch <NUM> to the sleeve end, shown by sleeve vertical axis <NUM> in <FIG>. In the embodiment shown in <FIG>, the deployed length LD, shown in <FIG>, is less than the fitting sleeve length FSL. In some embodiments, the deployed length LD may be greater than the FSL.

With additional reference to <FIG>, the single head pipe isolation device <NUM> may similarly be installed into pipe <NUM>. In operation, the pipe isolation device <NUM> may be installed to single block the pipe <NUM>. Pipe isolation device <NUM> operates in a manner like isolation device <NUM> but the pipe isolation device <NUM> blocks pipe <NUM> with only one sealing head, referred to as single sealing head <NUM>, when installed in the pipe <NUM>. In the first retracted position, pipe isolation device <NUM> may be disposed in a pipe branch <NUM> above the access opening <NUM> and a bottom pipe section <NUM> in the pipe <NUM>. An actuator <NUM> may be attached to the control bar head <NUM> of the pipe isolation device <NUM>. The actuator <NUM> moves the control bar head <NUM> downwards in the pipe branch <NUM> to convey the pipe isolation device <NUM> into the lateral access opening <NUM> during the installation of the pipe isolation device <NUM>.

Actuator <NUM> may move the control bar head <NUM> linearly downwards and along the vertical axis of the pipe branch <NUM> and through the pipe branch <NUM>. As the control bar head <NUM> moves downwards, the pipe isolation device <NUM> is conveyed through the lateral access opening <NUM> where the single sealing head <NUM> engages the internal wall <NUM> at the pipe bottom section <NUM> of the pipe <NUM>. Pipe isolation device <NUM> is in the fully retracted position with the single sealing head <NUM> in the locked state as the pipe isolation device <NUM> moves through the pipe joint <NUM> and through the lateral access opening <NUM>. Pipe isolation device <NUM> is maintained in the fully retracted position until the pipe isolation device <NUM> reaches the pipe bottom section <NUM> of the pipe <NUM>. The locking mechanism may be located between the control bar head <NUM> and the single sealing head <NUM>. The locking mechanism may be formed by the pin <NUM>.

When the single sealing head <NUM> engages the internal wall <NUM> of the pipe <NUM> the downward force on the control bar head <NUM> provided by actuator <NUM> results in an applied force being applied to the single sealing head <NUM>. First pin <NUM> formed by a shear pin shears in response to the applied force. The locking mechanism, that may be formed by the pin <NUM>, is sheared to release the single sealing head <NUM> from the first retracted position at the pipe bottom section <NUM>. When in the unlocked state, the single sealing head <NUM> is not biased in the first retracted position and is permitted to slide with respect to the control bar head <NUM>.

As the control bar <NUM> moves downwards, the single sealing head <NUM> slides with respect to the control bar head <NUM> and slides forward in the pipe <NUM> away from the vertical axis of the control bar head and the pipe branch <NUM>. More specifically, single sealing head <NUM> moves forward, or outwardly from the vertical axis of the pipe branch <NUM>, in the pipe <NUM> with the pad <NUM> sliding on the internal surface <NUM> of the pipe <NUM>. Pad <NUM> help to center the single sealing head <NUM> in the pipe <NUM>. As the single sealing head <NUM> moves forward, the single sealing head <NUM> slides with respect to the control bar head <NUM>.

As the control bar head <NUM> moves downwards, the control bar head <NUM> engages the internal wall <NUM> at the bottom of the pipe <NUM> directly below the lateral access opening <NUM>. This results in the pipe isolation device <NUM> being positioned in the fully set position with the single sealing head <NUM> in the first set position. Single sealing head <NUM> forms a single, primary seal to fluid flowing in the pipe <NUM>.

Pipe isolation device <NUM> may be disposed within the bounds of the sleeve ends <NUM>, <NUM> when positioned from the fully retracted position to the fully set position. Single sealing head <NUM> has a cylindrical shape. Pipe isolation device <NUM>, in some embodiments, is configured for a pipe having a lateral access opening <NUM> that has a diameter size approximately equal to the internal diameter of the pipe <NUM> being sealed, sometimes referred to as a size-on-size tap. A fitting sleeve length FSL may be measured from the vertical axis <NUM> extending through the center of the pipe branch <NUM> to the sleeve end, shown by sleeve vertical axis <NUM> in <FIG>. In the embodiment shown in <FIG>, the deployed length LD is less than the fitting sleeve length FSL. In some embodiments, the deployed length LD may be greater than the FSL.

Referring to <FIG>, another embodiment of a pipe isolation device is shown, and is referred to as pipe isolation device <NUM>. Like part numbers of embodiments of the pipe isolation devices <NUM>, <NUM>, <NUM> are labeled with like reference numbers. Pipe isolation device <NUM> is moveable between the fully set position, as shown in <FIG>, and the fully retracted position, as shown in <FIG>. Pipe isolation device <NUM> moves between the fully retracted position and the fully set position in a similar manner as described with respect to the pipe isolation device <NUM>. Pipe isolation device <NUM> includes control bar head <NUM>, a first sealing head <NUM>, and a second sealing head <NUM>. First sealing head <NUM> includes a first seal assembly <NUM> and the second sealing head <NUM> includes a second seal assembly <NUM>. A center axis <NUM> extends through the sealing heads <NUM>, <NUM> and is perpendicular a vertical axis <NUM> extending through the control bar head <NUM>. In some embodiments, the center axis <NUM> may form a centerline for a pipe in which the pipe isolation device <NUM> is deployed in the fully set position.

Referring to <FIG>, an exploded view of an embodiment of the first seal assembly <NUM> disassembled from the first main body <NUM> of the first sealing head <NUM> is shown. First main body <NUM> may have a cylindrical shape. First seal assembly <NUM> includes a first seal element <NUM>, a first retaining ring <NUM>, a first stiffening ring <NUM>, and a first nose ring <NUM>. Mechanical fasteners <NUM>, such as screws or bolts, may be used in securing components of the first seal assembly <NUM> together. In some embodiments, the mechanical fasteners <NUM> may extend through fastener openings <NUM> in the first retaining ring <NUM> and into mating attachment openings <NUM> in the first main body <NUM> to secure the first seal assembly <NUM> in an assembled position, as shown in <FIG>. One attachment opening <NUM> in the first main body <NUM> is shown in <FIG>. Seal elements <NUM>, <NUM> may be bonded or glued in the seal assemblies <NUM>, <NUM>. For example, the seal elements <NUM>, <NUM> may be bonded or glued to the main bodies <NUM>, <NUM>, the nose rings <NUM>, <NUM>, and the retaining rings <NUM>, <NUM>.

First main body <NUM> includes a first outer surface <NUM> extending around the circumference of the first main body <NUM>. First outer surface <NUM> forms an outer diameter (OD) of the first main body <NUM>. First main body <NUM> further includes a first face <NUM>, also referred to as a primary first face, that extends radially from the first outer surface <NUM> and extends around the circumference of the first main body <NUM>. First face <NUM> may be suitably transverse to the center axis <NUM>, shown in <FIG>, that extends through the sealing heads <NUM>, <NUM>. The transverse orientation of the first face <NUM> to the center axis <NUM> is continuous around the circumference of the first main body <NUM>. First main body <NUM> further includes a second face <NUM>, also referred to as a primary second face, that extends radially from the first main body <NUM> and extends around the circumference of the first main body <NUM>. Second face <NUM> also may be suitably transverse to the center axis <NUM>, as shown in <FIG>, that extends through the sealing heads <NUM>, <NUM>. The transverse orientation of the second face <NUM> to the center axis <NUM> is continuous around the circumference of the first main body <NUM>.

Referring to <FIG>, an exploded view of an embodiment of the second seal assembly <NUM> disassembled from a second main body <NUM> of the second sealing head <NUM> is shown. Second main body <NUM> may have a cylindrical shape. Second seal assembly <NUM> may include a second seal element <NUM>, a second retaining ring <NUM>, a second stiffening ring <NUM>, and a second nose ring <NUM>. In this example, second seal element <NUM> has a seal front face formed by a second front face <NUM>. Mechanical fasteners <NUM>, such as screws, may be used in securing components of the second seal assembly <NUM> together. In some embodiments, the mechanical fasteners <NUM> may extend through fastener openings <NUM> in the second retaining ring <NUM> and into mating attachment openings <NUM> in the second main body <NUM> to secure the second seal assembly <NUM> in an assembled position, as shown in <FIG>. One attachment opening <NUM> in the second main body <NUM> is shown in <FIG>.

Seal elements <NUM>, <NUM> may be bonded or glued in the seal assemblies <NUM>, <NUM>. For example, the seal elements <NUM>, <NUM> may be bonded or glued to the main bodies <NUM>, <NUM>, the nose rings <NUM>, <NUM>, and the retention rings <NUM>, <NUM>. To aid with installation of the seal elements <NUM>, <NUM> onto the main bodies <NUM>, <NUM> of the seal assemblies <NUM>, <NUM>, the retaining rings <NUM>, <NUM> may be split into several segments, and the stiffening rings <NUM>, <NUM> may be made integral with the retaining rings <NUM>, <NUM>. Seal elements <NUM>, <NUM> may also undergo a heat treatment, normalizing or softening process.

Second main body <NUM> includes a second outer surface <NUM> extending around the circumference of the second main body <NUM>. Second outer surface <NUM> forms an outer diameter (OD) of the second main body <NUM>. Second main body <NUM> further includes a first face <NUM>, also referred to as a secondary first face, that extends radially from the second outer surface <NUM> and extends around the circumference of the second main body <NUM>. First face <NUM> may be suitably transverse to the center axis <NUM>, shown in <FIG>, that extends through the sealing heads <NUM>, <NUM>. The transverse orientation of the first face <NUM> to the center axis <NUM> is continuous around the circumference of the second main body <NUM>. Second main body <NUM> further includes a second face <NUM>, also referred to as a secondary second face, that extends radially from the second main body <NUM> and extends around the circumference of the second main body <NUM>. As shown in <FIG>, second face <NUM> also may be suitably transverse to the center axis <NUM> that extends through the sealing heads <NUM>, <NUM>. The transverse orientation of the second face <NUM> to the center axis <NUM> is continuous around the circumference of the second main body <NUM>.

Referring to <FIG>, a cross-sectional view of the pipe isolation device <NUM> is shown in the fully set position. First seal assembly <NUM> has a first axially-offset configuration on the first sealing head <NUM>. In the first axially-offset configuration, the first seal assembly <NUM> surrounds the first main body <NUM> in an elliptical shape, as shown in <FIG>. A first bottom section <NUM> of the first seal assembly <NUM> is located on the first main body <NUM> at a bottom circumferential location on the circumference of the first main body <NUM> and at a first axial position parallel to the center axis <NUM>. A first top section <NUM> of the first assembly <NUM> is positioned at a top circumferential location on the circumference of the first main body <NUM> and at a second axial position parallel to the center axis <NUM>. First bottom section <NUM> may include component bottom sections of the first seal element <NUM>, the first retaining ring <NUM>, the first stiffening ring <NUM>, and the first nose ring <NUM>. First top section <NUM> may include component top sections of the first seal element <NUM>, the first retaining ring <NUM>, the first stiffening ring <NUM>, and the first nose ring <NUM>.

The bottom circumferential location and the top circumferential location are opposite one another on the first main body <NUM>. As shown in <FIG>, the bottom circumferential location of the first bottom section <NUM> of the first seal assembly <NUM> is at a bottom portion of the first main body <NUM> and the top circumferential location of the first top section <NUM> of the first seal assembly <NUM> is at a top portion of the first main body <NUM>.

The axial-offset configuration of the first seal assembly <NUM> is illustrated by a first assembly axis <NUM> and a second assembly axis <NUM> shown in <FIG>. First assembly axis <NUM> is perpendicular to the center axis <NUM> and extends through the first bottom section <NUM>. Second assembly axis <NUM> is perpendicular to the center axis <NUM> and extends through the first top section <NUM>. As shown in <FIG>, the first assembly axis <NUM> may extend through a center of the section of the first seal element <NUM> in the first bottom section <NUM>. Second assembly axis <NUM> may extend through a center of the section of the first seal element <NUM> in the first top section <NUM>. The axial-offset length for the axial-offset configuration of the first seal assembly <NUM> is designated as OA1 in <FIG>. In some embodiments, the axial-offset length OA1 is such that the first bottom section <NUM> is fully axially offset from the first top section <NUM> where the first bottom section <NUM> does not underlie any portion of the first top section <NUM>. For example and as shown in <FIG>, the component bottom sections of the first seal element <NUM>, the first retaining ring <NUM>, the first stiffening ring <NUM>, and the first nose ring <NUM> are axially offset and do not underlie any portion of the component top sections of the first seal element <NUM>, the first retaining ring <NUM>, the first stiffening ring <NUM>, and the first nose ring <NUM>. In some embodiments, the axial-offset length OA1 is such that the first bottom section <NUM> is partially axially offset from the first top section <NUM> where the first bottom section <NUM> underlies a portion of the first top section <NUM>.

In the illustrated embodiment, second seal assembly <NUM> has a second axially-offset configuration on the second sealing head <NUM>. In the second axially-offset configuration, the second seal assembly <NUM> surrounds the second main body <NUM> in an elliptical shape on the second main body <NUM>. A second bottom section <NUM> of the second seal assembly <NUM> is located on the second main body <NUM> at the bottom circumferential location on the circumference of the second main body <NUM> and at a third axial position parallel to the center axis <NUM>. A second top section <NUM> of the second seal assembly <NUM> is positioned at the top circumferential location on the circumference of the second main body <NUM> and at a fourth axial position parallel to the center axis <NUM>. Second bottom section <NUM> may include component bottom sections of the second seal element <NUM>, the second retaining ring <NUM>, the second stiffening ring <NUM>, and the second nose ring <NUM>. Second top section <NUM> may include component top sections of the second seal element <NUM>, the second retaining ring <NUM>, the second stiffening ring <NUM>, and the second nose ring <NUM>.

The bottom circumferential location and the top circumferential location on the circumference of the second main body <NUM> are opposite one another on the second main body <NUM>. As shown in <FIG>, the bottom circumferential location of the second bottom section <NUM> of the second seal assembly <NUM> is at a bottom portion of the second main body <NUM> and the top circumferential location of the second top section <NUM> of the second seal assembly <NUM> is at a top portion of the second main body <NUM>.

The axial-offset configuration of the second seal assembly <NUM> is illustrated by a third assembly axis <NUM> and a fourth assembly axis <NUM> shown in <FIG>. Third assembly axis <NUM> is perpendicular to the center axis <NUM> and extends through the second bottom section <NUM>. Fourth assembly axis <NUM> is perpendicular to the center axis <NUM> and extends through the second top section <NUM>. As shown in <FIG>, the third assembly axis <NUM> may extend through a center of the section of the second seal element <NUM> in the second bottom section <NUM>. Fourth assembly axis <NUM> may extend through a center of the section of the second seal element <NUM> in the second top section <NUM>. The axial-offset length for the axial-offset configuration of the second seal assembly <NUM> is designated as OA2 in <FIG>. In some embodiments, the axial-offset length OA2 is such that the second bottom section <NUM> is fully axially offset from the second top section <NUM> where the second bottom section <NUM> does not underlie any portion of the second top section <NUM>. For example and as shown in <FIG>, the component bottom sections of the second seal element <NUM>, the second retaining ring <NUM>, the second stiffening ring <NUM>, and the second nose ring <NUM> are axially offset and do not underlie any portion of the component top sections of the second seal element <NUM>, the second retaining ring <NUM>, the second stiffening ring <NUM>, and the second nose ring <NUM>. In some embodiments, the axial-offset length OA2 is such that the second bottom section <NUM> is partially axially offset from the second top section <NUM> where the second bottom section <NUM> underlies a portion of the second top section <NUM>.

The axially-offset configuration of the first seal assembly <NUM> provides the benefit of helping to provide a compact first sealing head <NUM> and a compact deployed length for the pipe isolation device <NUM>. The sliding engagement between the control bar head <NUM> and the first sealing head <NUM> creates a first track axis <NUM> and a first main body <NUM> with limited space for the first seal assembly <NUM>. The axially-offset configuration of the second seal assembly <NUM> provides the benefit of helping to provide a compact second sealing head <NUM> and a compact deployed length LD for the pipe isolation device <NUM>. The sliding engagement between the first sealing head <NUM> and the second sealing head <NUM> creates the second track axis <NUM> and a second main body <NUM> with limited space for the second seal assembly <NUM>.

Seal assemblies <NUM>, <NUM> are configured with axial-offset configurations to help provide the compact sealing heads <NUM>, <NUM> that allow for a compact deployed length LD for the pipe isolation device <NUM>. As discussed previously, limiting the deployed length LD helps prevent damage to a pipe due to the reaction loads of the pipe isolation device <NUM> against the pipe during operation of the pipe isolation device <NUM> in the pipe. In some embodiments, pipe isolation devices may have seal elements that are circular and mounted on sealing heads such that the seal elements have perpendicular configurations without an axial offset.

Referring to <FIG>, an embodiment of the first seal element <NUM> is shown. Second seal element <NUM> may be configured in a similar manner as the embodiment described with respect to the first seal element <NUM> shown in <FIG> show the orientation of the first seal element <NUM> when assembled on the pipe isolation device <NUM> in the fully set position, as shown in <FIG>. First seal element <NUM> may be made of an elastomeric material and may be stretchable. First seal element <NUM> may be stretched during assembly to mount the first seal element <NUM> on the first main body <NUM>. First seal element <NUM> is in the installed configuration where the first seal element has been stretched to form an elliptical shape and is mounted on the first main body <NUM>. First seal element may have an uninstalled configuration where the first seal element has a circular shape and has not been stretched and mounted on the first main body <NUM>. When being installed on the first main body <NUM>, the first seal element may be stretched from the circular position to the elliptical position to mount the first seal element on the first main body <NUM>. In some embodiments, the first seal element is twisted and stretched when positioning the first seal element from the uninstalled configuration to the installed configuration so that the first seal element has a perpendicular configuration, as described below.

First seal element <NUM> includes a base section <NUM>, an extension section <NUM>, and a flair section <NUM>. Base section <NUM>, as shown in <FIG>, has an inner surface <NUM>, a first ledge <NUM>, and a second ledge <NUM> that extend around a first seal opening <NUM>. Inner surface <NUM> is configured to abut against the first main body <NUM> when the first seal element <NUM> is assembled on the first sealing head <NUM>. Inner surface <NUM> forms the inner diameter (ID) of the first seal element <NUM>. First ledge <NUM> forms a first outer surface <NUM> and second ledge <NUM> forms a second outer surface. Outer surfaces <NUM>, <NUM> may be parallel to the inner surface <NUM> of the base section <NUM>. A stiffening ring pocket <NUM> is formed by the first ledge <NUM> and the extension section <NUM> and configured for the stiffening ring <NUM> to fit therein and extend around the first ledge <NUM>.

Extension section <NUM> is formed radially between the base section <NUM> and the flair section <NUM> and extends outwards from the base section <NUM>. Flair section <NUM> includes a seal outer surface <NUM> that extends around seal opening <NUM>. Seal outer surface <NUM> forms the outer diameter (OD) of the first seal element <NUM>. Extension section <NUM> further has a seal back face <NUM> that may extend from the base section <NUM> to the seal outer surface <NUM>. Seal back face <NUM> is the non-pressurized side of the seal element <NUM>.

According to the invention, an anti-extrusion device is used with the first seal element <NUM>. The anti-extrusion device is formed by a garter spring <NUM>. Garter spring <NUM> may be embedded in the first seal assembly <NUM>. Ends of the garter spring <NUM> are shown in <FIG>. In some embodiments, the garter spring <NUM> may be formed by a coil spring that may fully encircle the seal opening <NUM>.

Referring to <FIG>, an embodiment of the first retaining ring <NUM> is shown. Second retaining ring <NUM> may be configured in a similar manner as the embodiment described with respect to the first retaining ring <NUM> shown in <FIG>. First retaining ring <NUM> may be made of a metallic material. First retaining ring <NUM> has an elliptical shape. <FIG> shows the orientation of the first retaining ring <NUM> when assembled on the pipe isolation device <NUM> in the fully set position, as shown in <FIG>. First retaining ring <NUM> is shown in an installed orientation as if it were mounted on the first main body <NUM> with the center axis <NUM> extending through a retaining opening of the first retaining ring. First retaining ring may have a ring support face <NUM> that is perpendicular to the center axis <NUM> when in the assembled position. Ring support face <NUM> abuts against one side of the first seal element <NUM> to support the first seal element in a perpendicular configuration in the assembled position. Ring support face <NUM> continues around the circumference of the first retaining ring and is continuously perpendicular to the center axis <NUM> in the assembled position.

Referring to <FIG>, another embodiment of the first seal element <NUM> is shown. Second seal element <NUM> may be configured in a similar manner as the embodiment described with respect to the first seal element <NUM> shown in <FIG>. In this example, first seal element <NUM> may be made of an elastomeric material that may be stretched. <FIG> shows the orientation of the first seal element <NUM> when assembled on the pipe isolation device <NUM> in the fully set position, as shown in <FIG>. First seal element <NUM> is shown in an installed orientation as if it were mounted on the first main body <NUM> with the center axis <NUM> extending through the seal opening <NUM> of the first seal element <NUM>. The cross-section of the first seal assembly <NUM> has a perpendicular configuration to the center axis <NUM> when in the assembled position. The cross-section of the first seal assembly has a continuous perpendicular configuration to the center axis <NUM> around the circumference of the first main body <NUM> when in the assembled position.

Seal elements <NUM>, <NUM> may be manufactured (typically molded) in a circular ring shape. Seal elements <NUM>, <NUM> may be stretched into a twisted elliptical ring shape when installed on the main bodies <NUM>, <NUM> of the seal assemblies <NUM>, <NUM>, as shown in <FIG>. The stretched shape of the seal elements <NUM>, <NUM> maintains a cross-section which is perpendicular to the pipe internal diameter around the circumference of the seal elements <NUM>, <NUM>, even though the tops of the seal elements <NUM>, <NUM> are seated at a position further axially down the pipe than where the bottoms of the seal elements <NUM>, <NUM> are seated, as described with respect to <FIG>. A first garter spring <NUM> may be embedded in the body of the first seal element <NUM> and may be made of a metallic material. Ends of the first garter spring <NUM> may linked with like material or a seamless spring may be used. Garter spring <NUM> may be installed with no preload.

Referring to <FIG>, an embodiment of the first nose ring <NUM> is shown. Second nose ring <NUM> may be configured in a similar manner as the embodiment described with respect to the first nose ring <NUM> shown in <FIG>. First nose ring <NUM> may be made of a metallic material and may have an elliptical shape. <FIG> shows the orientation of the first nose ring <NUM> when assembled on the pipe isolation device <NUM> in the fully set position, as shown in <FIG>. First nose ring <NUM> is shown in an installed orientation as if it were mounted on the first main body <NUM> with the center axis <NUM> extending through a nose ring opening of the first nose ring <NUM>. In this example, first nose ring <NUM> has a first nose face <NUM> and a second nose face <NUM> that are perpendicular to the center axis <NUM> when in the assembled position. First nose face <NUM> abuts against one side of the first seal element <NUM> and second nose face <NUM> abuts against a face of the first main body <NUM> to support the first seal element <NUM> in a perpendicular configuration in the assembled position, see <FIG>. First nose face <NUM> and the second nose face <NUM> continue around the circumference of the first nose ring <NUM> and are continuously perpendicular to the center axis <NUM> in the assembled position.

Referring to <FIG>, a cross-sectional view of the pipe isolation device <NUM> is shown in the fully set position. A cross-sectional view of the first seal assembly <NUM> is circled and <FIG> is an enlarged cross-sectional view of the circled area "<NUM>" in <FIG>. A cross-sectional view of the second seal assembly <NUM> is circled and <FIG> is an enlarged cross-sectional view of the circled area "<NUM>" in <FIG>. A first parallel axis <NUM> is shown extending through the circled area "<NUM>" and the circled area "<NUM>". First parallel axis <NUM> is parallel to the center axis <NUM>.

Referring to <FIG>, an embodiment of the first seal assembly <NUM> on the first sealing head <NUM> is shown. The internal diameter of the base section <NUM> of the first seal element <NUM> abuts the first outer surface <NUM>, shown in <FIG>, of the first main body <NUM>. In some embodiments, first seal element <NUM> is configured to have a perpendicular configuration with respect to the first parallel axis <NUM>. Extension section <NUM> extends radially outwards from the base section <NUM> and in a direction perpendicular to the first parallel axis <NUM> to form the perpendicular configuration. The perpendicular configuration of the first seal element is formed continuously around the first main body <NUM>.

Stiffening ring <NUM> may be disposed in the stiffening ring pocket <NUM> and extends around the seal opening <NUM>, shown in <FIG>, to provide additional strength to the first seal element <NUM>. First retaining ring <NUM> may be disposed on one side of the first seal element <NUM> to secure the stiffening ring <NUM> and the first seal element <NUM> in place on the first main body <NUM>. First retaining ring <NUM> may abut against the stiffening ring <NUM> and the first seal element <NUM> to block the stiffening ring pocket <NUM>, shown in <FIG>. First retaining ring <NUM> may extend from a surface of the first main body <NUM> that is at a non-parallel angle with respect to the first parallel axis <NUM> so that the first retaining ring <NUM> extends at an angle from the first main body <NUM> towards the first sealing element <NUM>.

First seal element <NUM> and first retaining ring <NUM> may have a first inter-locking feature where the first retaining ring <NUM> has a surface that extends over and abuts the first ledge <NUM>. First nose ring <NUM> extends radially outwards from the first main body <NUM> and adjacent a side of the first sealing element <NUM>. First nose ring <NUM> may abut the side of the first seal element <NUM>. First seal element <NUM> and first nose ring <NUM> may have a second inter-locking feature where the first nose ring <NUM> has a surface that extends over and abuts the second ledge <NUM>. First nose ring <NUM> may extend radially from the first main body <NUM> in a perpendicular direction with respect to first parallel axis <NUM> and may be disposed adjacent to the garter spring <NUM> in the first sealing element <NUM>.

First sealing element <NUM> may further include an internal diameter (ID) sealing feature for providing a second seal between the first sealing element <NUM> and the first main body <NUM> of the first sealing head <NUM>. The ID sealing feature provides an interference fit and may be located on the front, back, or ID of the first seal element <NUM>. The ID sealing feature may seal against the first main body <NUM>, the first nose ring <NUM>, or the first retaining ring <NUM>. In the embodiment shown in <FIG>, the ID sealing feature is formed by a first ID sealing ring <NUM> that extends from the ID of the first sealing element <NUM>. First ID sealing ring <NUM> may be integral with the first sealing element <NUM> or may be a separate ring that extends around the first main body <NUM>. First sealing element <NUM> is disposed between the first retaining ring <NUM> and the first nose ring <NUM> to secure the first sealing element <NUM> in place around the first main body <NUM>. Mechanical fasteners may be used to press the first retaining ring <NUM> and the first nose ring <NUM> against the first seal element <NUM> to press fit the first seal element <NUM> in place on the first main body <NUM>.

Referring to <FIG>, an embodiment of the second seal assembly <NUM> on the second sealing head <NUM> is shown. Embodiments of the second seal assembly disclosed may be used on the first sealing head <NUM> and/or the second sealing head <NUM>. The inner diameter of base section <NUM> of the second seal element <NUM> abuts the second outer surface <NUM>, shown in <FIG>, of the second main body <NUM>. In some embodiments, second seal element <NUM> is configured to have a perpendicular configuration with respect to the first parallel axis <NUM>. Extension section <NUM> extends radially outwards from the base section <NUM> and in a direction perpendicular to the first parallel axis <NUM> to form the perpendicular configuration. The perpendicular configuration of the second seal element <NUM> is formed continuously around the second main body <NUM>.

Second stiffening ring <NUM> is disposed in the stiffening ring pocket <NUM> and extends around the seal opening <NUM>, shown in <FIG>, to provide additional strength to the second seal element <NUM>. Second retaining ring <NUM> is disposed on one side of the second sealing element <NUM> to secure the second stiffening ring <NUM> and the second seal element <NUM> in place on the second main body <NUM>. Second retaining ring <NUM> may abut against the second stiffening ring <NUM> and the second seal element <NUM>. Second retaining ring <NUM> may extend from a surface of the second main body <NUM> that is at a non-parallel angle with respect to the first parallel axis <NUM> so that the second retaining ring <NUM> extends at an angle from the second main body <NUM> towards the second sealing element <NUM>.

Second nose ring <NUM> extends radially outwards from the second main body <NUM> and adjacent a side of the second sealing element <NUM>. Second nose ring <NUM> may abut a side of the second seal element <NUM>. Second nose ring <NUM> may extend radially from the second main body <NUM> in a perpendicular direction with respect to first parallel axis <NUM> and may be disposed adjacent to a second garter spring <NUM> in the second sealing element <NUM>. Second sealing element <NUM> is disposed between the second retaining ring <NUM> and the second nose ring <NUM> to secure the second sealing element <NUM> in place around the second main body <NUM>. Mechanical fasteners may be used to press the second retaining ring <NUM> and the second nose ring <NUM> against the second seal element <NUM> to press fit the second seal element <NUM> in place on the second main body <NUM>.

Second sealing element <NUM> may further include an internal diameter (ID) sealing feature for providing a second seal between the second sealing element <NUM> and the second main body <NUM> of the second sealing head <NUM>. The ID sealing feature provides an interference fit and may be located on the front, back, or ID of the first seal element <NUM>. The ID sealing feature may seal against the second main body <NUM>, the second nose ring <NUM>, or the second retaining ring <NUM>. In the embodiment shown in <FIG>, the ID sealing feature is formed by a second sealing ring <NUM> that extends from the ID of the second sealing element <NUM>. Second sealing ring <NUM> may be integral with the second sealing element <NUM> or may be a separate ring that extends around the second main body <NUM>.

Referring to <FIG> and <FIG>, an embodiment of the first seal assembly <NUM> on the first sealing head <NUM> in a pipe <NUM> is shown. The embodiment disclosed with respect to <FIG> is shown assembled on the first sealing head <NUM> but may also be assembled on the second sealing head <NUM>. The OD of the seal element <NUM> provides an interference fit in the pipe which forms a seal. The frontside of the seal element <NUM> is the pressurized side, while the backside of the seal element <NUM> is the non-pressurized side.

Fluid pressure in the pipe <NUM> is shown directed in a forward direction by arrow <NUM>. First front face <NUM> is disposed on the pressurized side of the first seal element <NUM>. The internal diameter of the base section <NUM> of the first seal element <NUM> abuts the first outer surface <NUM>, shown in <FIG>, of the first main body <NUM>. In other words, the ID of the first seal element <NUM> sits on the cylindrical surface of the first main body <NUM> of the first sealing head <NUM>. The cylindrical surface of the first main body <NUM> in which the seal element <NUM> seats forms part of a gland. The gland includes surfaces <NUM>, <NUM>, as well as the seal-side surfaces of the retaining ring <NUM> and nose ring <NUM>. The gland conforms to the stretched shape of the seal element <NUM>. Seal element <NUM> sits between the first nose ring <NUM> (on the back side of the seal element <NUM>) and the first retainer ring <NUM> (on the frontside of the seal element <NUM>).

First seal element <NUM> includes an embodiment of the ID sealing feature formed by an ID sealing ring <NUM> disposed between the base section <NUM> of the first seal element <NUM> and the primary first face <NUM> of the first main body <NUM>. ID sealing ring <NUM> may be integral with the first seal element <NUM> or a separate ring extending around the first main body <NUM>. ID sealing ring <NUM> is shown extending beyond the primary first face <NUM> to better illustrate the location of the ID sealing ring <NUM> that abuts against the primary first face <NUM> and is disposed between the first sealing element <NUM> and the primary first face <NUM>.

First retention ring <NUM> and first stiffening ring <NUM> are configured in a similar manner as described with respect to the embodiments disclosed in <FIG>. First nose ring <NUM> extends radially outwards from the first main body <NUM> and adjacent a side of the first sealing element <NUM>. A section of the ID of the nose ring <NUM> is supported by a body shoulder <NUM> of the first main body <NUM>. In other words, a side of the first nose ring <NUM> abuts against an outer diameter (OD) of the body shoulder <NUM> and the primary second face <NUM> of the body shoulder <NUM>. Nose ring <NUM> may also extend beyond the shoulder <NUM> to extend radially outwards from the base section <NUM> of the first seal element <NUM> to form an inter-locking feature.

The anti-extrusion device formed by the garter spring <NUM> may be disposed adjacent to the back seal face <NUM> and the first nose ring <NUM>. Garter spring <NUM> is shown disposed below the pipe ID. An extrusion gap <NUM> is located between the first nose ring <NUM> and the pipe ID and is depicted by arrow <NUM>. Garter spring <NUM> is positioned in the first seal assembly <NUM> so that the OD of the garter spring <NUM> is disposed below the pipe ID to form a clearance gap <NUM> between the garter spring OD and the pipe ID. Clearance gap <NUM> may be present when a first fluid pressure is on the first front face <NUM> of the first seal element <NUM>, as shown in <FIG>. As the fluid pressure in the pipe increases, a higher, second fluid pressure is placed against the first front face <NUM>. The second fluid pressure may tend to expand the first seal element <NUM> and extrude the first seal element <NUM> into the seal gap <NUM>. As the first seal element <NUM> expands, the garter spring <NUM> resists expansion and is configured to have an OD that is greater than the height of the extrusion gap so that the garter spring <NUM> is obstructed from passing through the extrusion gap <NUM> to help prevent extrusion of the first seal element <NUM>.

Stiffening rings <NUM>, <NUM> described with respect to embodiments shown in <FIG><NUM> are a type of circumferential seal stiffener and can be installed in the stiffening ring pockets <NUM>. Stiffening rings <NUM>, <NUM> help prevent the seal elements <NUM>, <NUM> from stretching and distorting, also referred to as bunching, while the seal elements <NUM>, <NUM> travel through a branch opening of a pipe. There may be different embodiments of the stiffening rings <NUM>, <NUM>. In one embodiment, stiffening rings <NUM>, <NUM> are made of a harder material than the seal elements <NUM>, <NUM>. Some embodiments of the stiffening rings <NUM>, <NUM> are made of a metallic material with the seal elements <NUM>, <NUM> made of an elastomeric material that has a hardness less than the stiffening rings <NUM>, <NUM>. Stiffening rings <NUM>, <NUM> are shaped to fit in the respective stiffening ring pockets <NUM> of the seal elements <NUM>, <NUM> that are mounted on the respective main bodies <NUM>, <NUM> of the sealing heads <NUM>, <NUM>. In some embodiments, the stiffening rings <NUM>, <NUM> may be a separate ring or incorporated into the nose rings <NUM>, <NUM> or retaining rings <NUM>, <NUM>. The shape of the cross-section of the stiffening rings <NUM>, <NUM> may be circular, rectangular, or any other shape which conforms to the pocket shape of the stiffening ring pockets <NUM> in the seal elements <NUM>, <NUM>.

In other embodiments, the stiffening rings <NUM>, <NUM> may be flexible and each of the stiffening rings <NUM>, <NUM> may be bonded to one of the seal elements <NUM>, <NUM>. In these embodiments, the stiffening rings <NUM>, <NUM> may either be a layered fabric, a thin hard plastic, an elastomer, or metal. The flexible stiffening rings <NUM>, <NUM> is configured to be flexible to flex into a stretched shape of the assembled configuration where the stiffening rings are disposed in the stiffening ring pockets <NUM> and mounted on the main bodies <NUM>, <NUM>. The flexible stiffening rings <NUM>, <NUM> may be flexed into the stretched shape without permanently deforming, but stiff enough to prevent the seal elements <NUM>, <NUM> from bunching during installation of the pipe isolation device <NUM> into a pipe as the pipe isolation device <NUM> moves from the fully retracted position to the fully set position.

Seal elements <NUM>, <NUM> as assembled on the sealing heads <NUM>, <NUM> have advantages. The geometry of the seal elements <NUM>, <NUM> makes manufacturing and inspection more economical. For example, the seal cross-section maintains the same shape around the circumference of the seal elements <NUM>, <NUM>. This simplifies analysis of the seal elements <NUM>, <NUM>, and produces a more reliably uniform seal.

The ring shape of the seal elements <NUM>, <NUM> allows for a singular main piece for the main bodies <NUM>, <NUM> of the seal heads <NUM>, <NUM> rather than a bolted-together seal head. This reduces leak paths and reduces the high-stress points in the seal head mechanism. It removes any high-stressed fasteners which would be potential failure points. The perpendicular gland on each of the main bodies <NUM>, <NUM> is easier to machine into the main bodies <NUM>, <NUM> of the seal heads <NUM>, <NUM>. Variable, acute to obtuse shaped glands are more complicated to machine.

Referring to <FIG>, an embodiment of a third seal element is shown, and is identified with reference number <NUM>. Third sealing element <NUM> will be described for being assembled on the first sealing head <NUM> but may be assembled on the second sealing head <NUM> in a similar manner. Third seal element <NUM> may be manufactured in an installed configuration having an elliptical shape. Third seal element <NUM> may be a full disc seal, as shown in <FIG>. In some embodiments, the third seal element <NUM> may have a ring shape. The front and back of the third seal element <NUM> are both flat. A cross-section of the third seal element <NUM>, as shown in <FIG> may be approximated to form a variable trapezoidal shape from acute to obtuse around the profile of the third seal element <NUM>, due to the angle of the seal gland in order to fit on the first main body <NUM> of the first sealing head <NUM>. The OD of the third seal head <NUM> is variable around the circumference to maintain the proper interference with the pipe ID.

For the third seal element <NUM> having a ring-style shape, the third seal element <NUM> may be assembled on the first main body <NUM> in a manner like the first seal element <NUM>. For example, the third seal element <NUM> sits between a first nose ring <NUM> (on the back side of the third seal element <NUM>) and a first retainer ring <NUM> (on the front side of the third seal element <NUM>). The front side of the third seal element <NUM> is the pressurized side, while the back side of the third seal element <NUM> is the non-pressurized side. The ID of the third seal element <NUM> sits on the cylindrical surface of the first main body <NUM> of the first sealing head <NUM>. The OD of the third seal element provides an interference fit in the pipe which forms a seal. A second seal is formed by an ID sealing feature. This feature provides an interference fit and may be located on the front, back, or ID of the third seal element <NUM>, and may seal against the first main body <NUM>, the first nose ring <NUM>, or the first retaining ring <NUM>. A first stiffening ring <NUM> or other stiffening options discussed with respect to disclosed embodiments may be applied and used with the third seal element <NUM>.

For the third seal element <NUM> having the full-disc configuration shown in <FIG><NUM>, the third seal element <NUM> is squeezed between two plates which are secured with one or more fasteners to the first sealing head <NUM>. For example, on one end of the first sealing head <NUM>. To prevent leakage through the fasteners, the third seal element <NUM> may include seal rings around each fastener or a circumferential seal ring <NUM> which encompasses all the fasteners. Fastener holes <NUM> extend through the disc body <NUM> of the third seal element <NUM>, as shown in <FIG>.

Third seal element <NUM> has advantages. Third seal <NUM> helps prevent failure due to "bunching" when being installed due to the inherent locking nature of the parallelogram trapezoidal shaped gland. A third seal element <NUM> having a full-disc style seal can be held in place very robustly. Bunching issues are eliminated. Since the third seal element does not need to be stretched, installation on the first sealing head <NUM> is simplified.

Embodiments of the seal heads disclosed herein provides advantages over other seal heads that use cylindrically-shaped seal heads which are either inserted through a pipe branch on an angle and rotated into position, or smaller than pipe ID seals which need to be actuated. The geometry required for the seal heads for use in the sliding engagement mechanism of the pipe isolation device disclosed herein benefit from the seal assemblies disclosed herein. Embodiments of the seal heads disclosed employ cylindrical seal heads that have a slanted shape to allow for clearance to be deployed through a circular branch opening of a pipe that is smaller than the OD of the pipe to be sealed. Embodiments of the seal elements can then be deployed axially down the pipeline without the need for rotating the sealing heads with the seal elements into position.

Rings forming the seal assemblies may be changed along with the seal elements with different OD variations to allow the seal head to adapt to a range of pipe wall thicknesses. The rings are sized to provide enough clearance to prevent interference between the pipe ID and ring OD, while also reducing the radial gap between the pipe ID and ring OD to an amount that is manageable with aid from an anti-extrusion device. Extrusion resistance may be provided by any of the following anti-extrusion devices: a garter spring, fabric reinforcement, shielded backing, or a flexible ring. The movement of the seal elements through the pipe is axial, so having a reduced diameter on the backside of the seal element is advantageous. This protects the back side of the seal element while also minimizes the initial seal interference with the pipe to just the flare of the front side of the seal element. The minimized interference reduces the installation force required. When the seal element having a garter spring is pressurized, the garter spring can expand until it contacts the ID of the pipe.

Embodiments of the pipe isolation device may be configured to translate the right angle at a lateral access opening and to provide a compact tool by providing sliding engagements to withstand the challenging environments of pipelines, including high pressures, high temperatures, and different types of fluids. Depending on the application, the pipe isolation device of the present disclosure may be modified by adding additional sealing heads to become a triple, or more, block and bleed apparatus.

Claim 1:
A pipe isolation device, comprising:
a control bar head (<NUM>);
a first sealing head (<NUM>) having a first seal element (<NUM>) and a first sliding engagement, the first sliding engagement permitting the first sealing head to slide relative to the control bar head along a first fixed path and to traverse a right angle to gain access to an interior space of a pipe with a center axis (<NUM>) defining an axial direction;
a second sealing head (<NUM>) having a second seal element (<NUM>) and a second sliding engagement, the second sliding engagement permitting the second sliding head to slide on the first sealing head along a second fixed path and to traverse the right angle to gain access to an interior space of the pipe;
the first seal element (<NUM>) disposed on the first sealing head (<NUM>), wherein the first sealing element has a first axially-offset configuration; and
the second seal element (<NUM>) disposed on the second sealing head (<NUM>), wherein the second sealing element has a second axially-offset configuration;
wherein the first seal element comprises an anti-extrusion device formed by a garter spring (<NUM>).