Cup for a pipeline inspection gauge

An in-line inspection tool for a pipeline comprises a body defining an axis, a sensor module coupled to the body, and a drive cup coupled to the body. The drive cup includes an outer surface with a plurality of axial channels, each of the axial channels including at least one bridge positioned therein that extends circumferentially across the channel.

FIELD

This application relates to the field of pipeline inspection tools, and particularly to cups for use with smart pipeline inspection gauges.

BACKGROUND

Pipeline systems are an integral component of global energy distribution. There are millions of miles of energy pipelines in the United States alone, delivering trillions of cubic feet of natural gas and Hundreds of billions of ton/miles of liquid petroleum products each year. To ensure the safety of these vast pipeline systems and often to comply with governmental regulations, pipeline operators must frequently service their pipelines and perform periodic inspections to assess pipeline integrity. Mechanical devices referred to as pipeline inspection gauges (which may also be referred to herein as “pigs” or “in-line inspection tools”) are often employed to perform these maintenance and inspection functions inside the pipeline. Different types of pigs are used to perform different tasks. These pigs include gauging tool pigs, cleaning pigs, and smart pigs.

Pigs must be capable of passing through pipelines of varying size. The varying size of a pipeline may be intentional in some instances. Pigs are often separated into sections or packages that house specific instrumentation or carry out specific functions. For instance, a pig can include a drive package for propulsion, a gauging plate package to determine smallest pipe diameters, a sensor package for carrying out signal detection for corrosion measurements, a navigational package for determining relative or global position, and a power package for powering any on-board electronics. The packages are tethered to one another via flexible joints that allow the respective packages to pass individually through bends in the pipe.

FIG. 10depicts an exemplary arrangement for a conventional pipeline pig100. The pig100includes a circumferential pig body104defining a central axis108, a plurality of elastomeric drive cups110coupled to the pig body104, and at least one sensor package120coupled to the pig body104. The pig body104is flexible, at least in sections, thus allowing the pig100to flex and bend around curves and turns within a pipeline. The drive cups110are configured to engage the inner wall of the pipeline and support the pig body104centrally within the pipeline. The cups110generally include circumferential edges or lips that engage the interior wall of the pipeline and form a sealed/piston-like relationship with the pipeline. Fluid flowing through the pipeline causes a pressure to act against the surfaces of the cups and move the pig100upstream through the pipeline. The sensor package120includes a plurality of sensors (not shown) which may be arranged in various sections of the pig and are configured take various measurements within the pipeline.

While conventional pipeline pigs such as that shown inFIG. 10have traditionally been successful in travelling through pipelines of a single diameter (e.g., 6-inch or 8-inch pipelines) such pigs are not always successful in travelling through pipelines with multiple diameters (e.g., both 6-inch and 8-inch). In particular, while the drive cup may have some flexibility, the cup tends to fold and/or bend when compressed into a smaller diameter pipelines, thus resulting in openings between the cup and the inner surface of the pipeline. When openings exist between the cup and the inner surface of the pipeline, the seal is broken and fluid within the pipeline flows through the opening and around the cup. As a result, there is a loss of pressure on the drive cup, and the cup is not propelled through the pipeline in the proper manner.

In view of the foregoing, it would be advantageous a drive mechanism for a pipeline inspection gauge that is capable of properly propelling the device through a pipeline with multiple diameters. It would be of further advantage if the drive mechanism were provided by a relatively simple device such as an improved cup capable of producing a seal along the inner surface of the pipeline across the multiple pipeline dimensions. It would also be advantageous if such a drive mechanism could be produced inexpensively and could be incorporated into new pipeline inspection gauges or retrofitted onto existing gauges.

SUMMARY

In at least one embodiment, an in-line inspection tool for a pipeline comprises a body defining an axis, a sensor module coupled to the body, and a drive cup coupled to the body. The drive cup includes an outer surface with a plurality of axial channels, each of the axial channels including at least one bridge positioned therein that extends circumferentially across the channel.

In at least one embodiment, a drive cup for an in-line inspection tool for a pipeline includes a frustoconical outer surface having a front portion and a rear portion, the front portion defining a smaller diameter than the rear portion. The drive cup further includes a plurality of axial channels defined on the outer surface, each of the axial channels defining a radial depth. Additionally, the drive cup includes a plurality of bridges positioned in each of the axial channels, each of the bridges extending circumferentially across the channel and radially for the depth of the channel.

In at least one embodiment, a method of propelling a pipeline inspection gauge through a pipeline comprises inserting the pipeline inspection gauge into the pipeline, the pipeline inspection gauge including a drive cup having an outer surface with a plurality of axial channels, a first set of bridges extending across the axial channels at a first diameter portion of the outer surface, and a second set of bridges extending across the axial channels at a second diameter portion of the outer surface. The method further comprises engaging the outer surface of the drive cup including the first set of bridges with a first inner surface of the pipeline. The method also comprises allowing the drive cup to move within the pipeline as a result of a fluid pressure on the drive cup. Furthermore, the method comprises engaging the outer surface of the drive cup including the second set of bridges with a second inner surface of the pipeline, wherein the second inner surface of the pipeline is defined by a different diameter than the first inner surface.

The above described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings. While it would be desirable to provide an in-line inspection tool that provides one or more of these or other advantageous features, the teachings disclosed herein extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the above-mentioned advantages.

DETAILED DESCRIPTION

A drive cup10for a pipeline inspection gauge is shown inFIGS. 1-5. The drive cup10includes a front portion12, a sidewall14, and a rear portion16. The sidewall14includes a generally frustoconical outer surface30defined along a central axis18. A plurality of axial channels40are formed in the sidewall14. Each of the axial channels40includes one or more bridges50that extend circumferentially from one side to another side of the associated channel. As explained in further detail herein, the channels40are configured to move between an expanded state and a contracted state when the outer surface30of the cup10engages different pipeline dimensions. In each state, the bridges50assist in maintaining a seal between the outer surface30of the cup10and the inner surface of the pipeline.

The drive cup10is a unitary component wherein all of the parts are integrally formed together, such as by molding. Accordingly, the drive cup10may be considered to be monolithic such that various components of the cup are non-removable from other components without destruction of the cup as a whole. The material that forms the cup10is resilient, flexible, generally heat-resistant, oil-resistant, and impervious to fluid. In at least one embodiment, the cup10is comprised primarily or entirely of an elastomeric material, such as polyurethane. However, it will be recognized that the cup10may alternatively be formed of different or additional materials, such as natural rubbers or any of various polymer materials. In at least one embodiment the cup10may include a metallic skeleton that provides additional support structures which are over-molded with the elastomer or other material.

The front portion12of the drive cup10is generally circular or cylindrical in shape and includes a face20with a central hub22. The face20is generally planar with a circular outer perimeter24. Front ends of the channels40open into the face20along the outer perimeter24, forming indentations along the outer perimeter24of the face20. The hub22is centrally located on the face and configured to receive the body of the pig (e.g., body104ofFIG. 10). The hub22is sealed against the body of the pig such that fluids, such as oil and gas, are prevented from passing through the hub22. While the embodiment of the drive cup10disclosed herein includes the hub22, it will be recognized that in at least some embodiments, the drive cup10does not include a hub22.

The sidewall14of the drive cup10has a generally frustoconical outer surface30. It will be recognized that the frustoconical outer surface30does not define a frustum of a perfect cone but instead refers to a surface that is generally cone shaped with the front portion having a smaller diameter than the rear portion. Also, it will be recognized that the generally frustoconical outer surface30also includes numerous surface irregularities, as described herein.

The sidewall14includes plurality of ribs32separated by a plurality of channels40. Each rib32is somewhat curved and extends axially and radially away from the front portion12of the cup10, along the frustoconical surface of the sidewall14, until it reaches the rear portion16of the cup10. The ribs32are arranged in a circumferential manner and evenly spaced around the entire circumference of the cup10. Each rib32includes a generally smooth outer surface that is configured to seal against the inner surface of a pipe at any of a plurality of different diameters defined along the length of the rib32. In other words, the cross-sectional shape of the surface of the rib32is that of an arc, with the radius of the arc changing along the various axial positions of the rib32between the front portion12and the rear portion16of the cup10.

Axial channels40(which may alternatively be referred to as axial “grooves”) are formed between each of the ribs32on the sidewall14. Like the ribs32, the axial channels40also extend between the front portion12and the rear portion16of the cup10. Each of the axial channels40is generally V-shaped in cross-section with two angled walls42,44. A valley line46is defined along the length of the channel40such that it extends along the inner portion of the two angled walls42,44. The V-shaped cross-section of each channel40may be considered to define a top and a bottom of each channel, wherein the bottom of the channel is at the tip of the “V” and the top of the channel is opposite the tip at the wide end of the “V.” Each of the axial channels40has a radial depth from top to bottom that is greater than the radial depth of the adjacent ribs32. Furthermore, each of the channels40may be considered to have a width that is defined by the distance between the two angled walls42,44(accordingly, the width of the channel is greater at the top than at the bottom). The width of the channels gradually tapers from a wider first width at the rear portion16of the cup10to a narrower second width at the front portion12of the cup10. As explained in further detail below, the V-shaped structure of the axial channels40allows the angled walls42,44to fold along the valley line46such that the channels40collapse inwardly and the ribs32are drawn closer together when the cup10is in a collapsed state. Conversely, when the cup10is in an expanded state, the channels open and the ribs32are positioned at a greater distance from one another. It will be recognized that while one configuration for the axial channels has been disclosed herein, various other configurations are also possible. For example, while the valley line46is disclosed herein as being a well-defined crease, in at least some embodiments, the valley line46may be provided by a small radius or somewhat flattened bottom portion. As yet another example, while the channels are described herein as gradually tapering from a wider the rear portion to a narrower front portion, in at least some embodiments the width of the channel does not taper. Also, in at least some embodiments, the axial channels may not extend completely from the front portion to the rear portion of the cup, and instead begin in a middle portion of the cup and extend from the middle portion toward the rear portion or from the middle portion toward the front portion.

A plurality of bridges50are positioned in each of the axial channels40. Each of the bridges50extends the entire radial depth of the associated channel40from the valley line46to the radially outward edge of the channel40. Each of the bridges also extends circumferentially across the associated channel40and provides a connection from one rib32on one side of the channel to an adjacent rib on an opposite side of the channel. In other words, the bridges50traverse the axial channels and provide a connection from one side of the channel to an opposite side of the channel such that the outer surface30of the cup10is smooth and uninterrupted when moving along the bridge50between adjacent ribs32. As a result, there are no surface irregularities between adjacent ribs32along the path provided by the bridge50on the outer surface30of the cup10. Each of the bridges50may also be considered to split the channel into different axial sections, including one section on one axial side of the bridge and another axial section on a different axial side of the bridge. While the bridges described herein as extending “circumferentially” across the channel, it will be recognized that this circumferential extension is not limited to a perfectly circumferential traversal of the channel and instead refers to a traversal from one side of the channel to the other. As such the bridge50may include various portions with axial components as well as circumferential components.

In the embodiments disclosed herein, the bridges50are all chevron-shaped and each bridge50includes a first panel52, a second panel54, and a tip56. The first panel52provides a first portion of the bridge that extends inwardly for the entire depth of the channel40(i.e., from a top of the channel to a bottom of the channel). The second panel54provides a second portion of the bridge50that extends inwardly from the entire depth of the channel40. The first panel52and the second panel54are both oriented at an angle within the channel and meet at the tip56. The tip56defines a mid-section for the bridge that extends radially into the channel40. When viewed from the outer surface30of the cup10, each tip56points away from the front portion12and toward the rear portion16of the cup10. The end of the first panel52that is opposite the tip56(and closer to the front portion12of the cup) is connected to a first rib32on one side of the channel40and defines a first end of the bridge50. Similarly, the end of the second panel54that is opposite the tip56(and closer to the front portion12of the cup) is connected to a second rib32on an opposite side of the channel40and defines a second end of the bridge50. Both the first panel52and the second panel54are impervious to fluid. Accordingly, the bridge50not only provides a circumferential path across the channel40, but also blocks fluid from flowing through the channel40.

The bridges50include forward bridges62and middle bridges64positioned in each of the channels40of the cup10. The forward bridges62are positioned in the channels40such that they are closer to the front portion12of the cup10and all arranged along a common circumference of the frustoconical sidewall14. For example, in at least one embodiment the forward bridges62are all positioned along a circumference of the sidewall14that is associated with a six inch diameter at the outer surface30.

The rear bridges64are positioned closer to the rear portion16of the cup10and all arranged along another common circumference of the frustoconical sidewall14. For example, in at least one embodiment the middle bridges64are all positioned along a circumference of the sidewall that is associated with an eight inch diameter at the outer surface30.

While the embodiments disclosed herein include forward bridges62and rear bridges64in each of the channels40, it will be recognized that in various embodiments of the cup10fewer or additional bridges50may be provided in each of the channels40. For example, each channel may alternatively include one, three, four or more bridges, each of the bridges associated with a specific circumference or circumferential range such that the bridges50are configured to seal the outer surface30of the cup against the inner surface of a pipeline having a certain diameter or range of diameters. Additionally, it will be recognized that while one configuration of the bridges50has been disclosed herein, various other configurations are also possible. For example, the chevron-shaped bridges may point a different direction that that shown in the figures (e.g., toward the front portion instead while the rear portion of the cup). Also, the bridges50could be of a different shape, such as a curved or arc shape (e.g., similar to a water dam). As yet another example, while the forward bridges62are disclosed herein as being slightly smaller in size than the rear bridges64, in at least some embodiments, all of the bridges have the same size.

The rear portion16of the cup10defines a greater diameter than the front portion12of the cup10. The rear portion includes a rim66which separates the outer surface30from the inner surface of the cup10. The rear portion16further includes a plurality of chevron-shaped sections68at the end of each channel40. These sections68are similar in shape to the bridges50and define a closed end of each channel40. Because these sections68are arranged along the rim66, they are positioned along a circumference of the cup10that is slightly greater than the circumference than that associated with the rear bridges64.

With reference now toFIGS. 6-7B, operation of the cup10within a pipeline is disclosed. As shown inFIG. 6, a pipeline90may include different sections, including a smaller diameter section92(e.g., a six-inch diameter section) shown on the right side of the illustration, and a larger diameter section94(e.g., an eight-inch diameter section) shown on the left side of the illustration. When the cup10is in the smaller diameter section92, the cup10is in a collapsed state wherein all of the ribs32are closer together, the channels40are narrowed and/or completely closed, and the panels52,54of the bridges50are folded at the tips56. It will be recognized that while one exemplary size and shape for the cup is shown in the figures and disclosed herein, various other sizes and shapes are also possible. For example, the dual-diameter cup may be further configured for use with different diameter pipelines or pipelines with more than just two diameters (e.g., six inch, eight inch, ten inch, twelve inch, etc., or any of various other diameters).

FIG. 7Ashows an illustration of one of the channels40when the cup is in the compressed state. As noted by the arrows82, the ribs32on opposing sides of the channel40are forced closer together in this state, the bridges fold, and the circumferential width of the channel40is narrowed. In this compressed state, the outer surface30of the cup10associated with the forward bridges62forms a seal with the inner surface of the pipeline90. Because the material that forms the cup10is impervious, and because the channels40are all blocked by the bridges50, fluid pressure in the pipeline propels the cup forward, as noted by the arrows96. In particular, the outer surface30of the cup10seals the pressure on the front of the cup from the area behind the cup resulting in a difference in pressure across the cup, and this difference in pressure across the cup propels the cup (and the associated pig) through the pipeline90.

With continued reference toFIGS. 6-7B, as the cup10moves forward in the pipeline90(i.e., from right to left), the cup10moves through a transition region93and encounters the larger diameter section94of the pipeline90, shown on the left side of the illustration. When the cup10moves into the larger diameter section94, it changes to an expanded state. In particular, when the cup10moves into the larger diameter section94, the force of the fluid against the inner surface of the cup10, and the resilient nature of the bridges50, forces the channels40to expand and the ribs32are moved further apart.FIG. 7Bshows an illustration of one of the channels40when the cup is in the expanded state. As noted by the arrows84, in the expanded state the bridges50unfold, the ribs32on opposing sides of the channel40are forced apart, and the circumferential width of the channel40is enlarged. In this expanded state, the outer surface30of the cup10associated with the rear bridges64forms a seal with the inner surface of the pipeline90.

In view of the foregoing, it will be recognized that the drive cup10described herein is capable of moving through a pipeline90, and the outer surface30of the cup10is configured to seal against the inner surface of the pipeline90at several different diameters. For example, the cup10may move between smaller diameter sections and larger diameter sections of the pipeline time and time again, all while maintaining a good seal against the pipe such that the drive cup10and any components attached thereto are propelled through the pipeline90. The drive cup10is configured for use with a pipeline inspection gauge such as the exemplary pipeline inspection gauge100ofFIG. 10, wherein the improved cup10is used instead of the conventional cups110. The improved drive cup10may be used in association with new pigs or may be retrofitted onto existing pigs. Moreover, the drive dup10may be configured for use with any of various types of pigs, including gauging tool pigs, cleaning pigs, and smart pigs.

While one embodiment of the drive cup has been shown and described above in association withFIGS. 1-5(with operation described in association withFIGS. 6-7B), it will be recognized that various alternative embodiments of the drive cup are also possible. For example,FIGS. 8 and 9show a second embodiment of the drive cup wherein each of the channels40includes one or more enlarged portions70. Each enlarged portion70is associated with a location in the channel40where one of the bridges50is positioned. The angled walls42,44of the channel40are differently shaped at the enlarged portions70than at other stretches of the channel40. For example, the angled walls42,44at the enlarged portions70are wing-like shapes with a truncated end74and a tip end76. The truncated end74of the enlarged portion70is defined by two circumferentially opposed shoulders72on opposite sides of the channel40. The tip end76of the enlarged portion70is defined by opposing points78where the curved edges on the outer surface30meets the straight edges that extends radially into the channel down to the valley line46. Each enlarged portion70defines a greater circumferential width across the channel40than the width of the channel on either axial side of the enlarged portions70(i.e., the width of the channel40is narrower axially outward from the opposed shoulders72and the points78than within the enlarged portion70). Additionally, the enlarged portion70is wider at the truncated end74than at that tip end76. In other words, the width of the channel at the shoulders72is greater than the width of the channel40at the points78.

In the embodiment ofFIGS. 8 and 9, each of the chevron-shaped bridges50is positioned in one of the enlarged portions70of the channel40. To this end a first end58aof each chevron-shaped bridge50is joined to a first shoulder72a, and a second end58bof the chevron-shaped bridge50is joined to a second shoulder72bin the channel40. The shoulders72aand72bprovide a clearance for the bridge50within the channel40. Therefore, when the cup10is in a collapsed state, even if the ribs32are drawn completely together along some stretches of the channel40, the enlarged portions70of the channels40do not completely close and still provide space for the bridges50to fold into their collapsed state. This is different from the embodiment ofFIGS. 1-5wherein no clearance is allotted for the bridges50, and therefore the channels40cannot completely close when the cup10is in a collapsed state.

The two different embodiments disclosed herein provide different advantages for the cup10. In particular, in the first embodiment ofFIGS. 1-5, the design is simpler and easier to mold. However, in the second embodiment ofFIGS. 8-9, the enlarged portions70allow the channels40to collapse completely such that the cup10may be compressed into its smallest possible configuration. In contrast to the second embodiment, the channels in the first embodiment are prevented from fully closing because there is no extra space to accommodate the collapsed bridges50. Therefore, while the second embodiment ofFIGS. 8-9is somewhat more difficult to produce, it has additional advantageous functionality over the first embodiment ofFIGS. 1-5.

The foregoing detailed description of one or more embodiments of the drive cup for a pipeline inspection gauge has been presented herein by way of example only and not limitation. It will be recognized that there are advantages to certain individual features and functions described herein that may be obtained without incorporating other features and functions described herein. Moreover, it will be recognized that various alternatives, modifications, variations, or improvements of the above-disclosed embodiments and other features and functions, or alternatives thereof, may be desirably combined into many other different embodiments, systems or applications. Presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the appended claims. Therefore, the spirit and scope of any appended claims should not be limited to the description of the embodiments contained herein.