Pipeline plugging pig

Claim 2

In a method for operating a pipeline plugging pig, wherein the pig includes pig arresting means and pipeline blocking means, the steps comprising moving the pipeline plugging pig to a desired location in a pipeline, releasing energy stored in a first mechanical energy storage means carried on the pig, transmitting a force resulting from releasing said energy to move said arresting means into contact with the pipeline wall to stop the pig, blocking the pipeline with said blocking means to prevent the flow of fluid therethrough and thereby establish a fluid pressure force acting on at least a portion of the pig when fluid under pressure is in the pipeline, transmitting a force exerted by said fluid pressure to a second mechanical energy storage means carried on the pig, storing in the second mechanical energy storage means energy transferred thereto as a result of the fluid pressure force being transmitted thereto, releasing stored energy from said second storage means and transferring at least a portion thereof to said first energy storage means to replenish energy previously released therefrom, in response to the release of stored energy from the second storage means, applying a force to disengage said arresting means from the pipeline wall, and unblocking the pipeline.

Claim 5

A method as set forth in claim 2, wherein said energy storing means comprises a pair of energy storing means and wherein energy of one of said pair of storing means is applied to said stopping means to stop said plug, energy of said fluid is stored in the other of said pair of storing means, and thereafter, the fluid pressure is reduced and energy of said other storing means is applied to said stopping means to release the latter and is transferred to said one storing means to restore energy therein.

Claim 6

In a method for operating a pipeline plugging pig, wherein the pig includes pig arresting means and pipeline blocking means, the steps comprising moving the pipeline plugging pig to a desired location in a pipeline, releasing energy stored in a first set of springs carried on the pig, utilizing released energy from the springs to move said arresting means into contact with the pipeline wall to stop the pig, blocking the pipeline with said blocking means to prevent the flow of fluid therethrough and thereby establish a fluid pressure force acting on at least a portion of the pig when fluid under pressure is in the pipeline, admitting pipeline fluid under pressure into said pig, transmitting a force exerted by said admitted fluid to a second set of springs on the pig, storing in the second set of springs energy transferred thereto from the admitted fluid under pressure, reducing the pressure of pipeline fluid admitted to said pig, releasing stored energy from said second set of springs and transferring at least a portion of the released energy to said first set of springs to replenish energy previously released therefrom, in response to the release of stored energy from sid said set of springs, applying a force to disengage said arresting means from the pipeline wall, and unblocking the pipeline.

Claim 7

In a method for operating a pipeline plugging pig, wherein the pig includes pig arresting means and pipeline blocking means, the steps comprising moving the pipeline plugging pig to a desired location in a pipeline, releasing energy stored in a first set of springs carried on the pig, utilizing released energy from the springs to move said arresting means into contact with the pipeline wall to stop the pig, blocking the pipeline with said blocking means to prevent the flow of fluid therethrough and thereby establish a fluid pressure force acting on at least a portion of the pig when fluid under pressure is in the pipeline, admitting pipeline fluid under pressure into said pig, transmitting a force exerted by said admitted fluid to a second set of springs on the pig, storing in the second set of springs energy transferred thereto from the admitted fluid under pressure, reducing the pressure of pipeline fluid admitted to said pig, releasing stored energy from said second set of springs and transferring at least a portion of the released energy to said first set of springs to replenish energy previously released therefrom, in response to the release of stored energy from sid said set of springs, applying a force to disengage said arresting means from the pipeline wall, and unblocking the pipeline.

Claim 8

A pipeline plugging pig comprising a body adapted to move through a pipeline, pig arresting means attached to said body and movable between a withdrawn position and an arresting position displaced outwardly of the body, means for a releasably sealing the interior of the pipeline to block fluid flow therethrough when the arresting means is in said arresting position, thereby to establish a differential fluid pressure between different portions of the body when fluid under pressure is in the pipeline, first spring means having an energy storage condition and a relaxed condition, linking means for linking said spring means to said arresting means, said first spring means operating on said linking means to place the arresting means in said withdrawn position when the first spring means is in its energy storage condition and to place the arresting means in its arresting position when the first spring means is in said relaxed condition, second spring means having a stored energy condition and a relaxed condition, said second spring means exerting in both its conditions a force greater than, and acting oppositely to, the force exerted by the first spring means when in its stored energy condition, means operable in response to said differential fluid pressure for placing said second spring means in its energy storage condition, means for selectively releasing the first and second spring means from their respective energy storage conditions, means operable in response to the release of stored energy from said second spring means for resetting the first spring means to its stored energy condition, thereby to move the arresting means to said withdrawn position and to permit the release of said sealing means from sealing engagement with the interior of the pipeline.

Claim 9

A pipeline plugging pig comprising a body adapted to move through a pipeline, pig arresting means attached to said body and movable between a withdrawn position and an arresting position displaced outwardly of the body, means for a releasably sealing the interior of the pipeline to block fluid flow therethrough when the arresting means is in said arresting position, thereby to establish a differential fluid pressure between different portions of the body when fluid under pressure is in the pipeline, first spring means having an energy storage condition and a relaxed condition, linking means for linking said spring means to said arresting means, said first spring means operating on said linking means to place the arresting means in said withdrawn position when the first spring means is in its energy storage condition and to place the arresting means in its arresting position when the first spring means is in said relaxed condition, second spring means having a stored energy condition and a relaxed condition, said second spring means exerting in both its conditions a force greater than, and acting oppositely to, the force exerted by the first spring means when in its stored energy condition, means operable in response to said differential fluid pressure for placing said second spring means in its energy storage condition, means for selectively releasing the first and second spring means from their respective energy storage conditions, means operable in response to the release of stored energy from said second spring means for resetting the first spring means to its stored energy condition, thereby to move the arresting means to said withdrawn position and to permit the release of said sealing means from sealing engagement with the interior of the pipeline.

Claim 10

The pipeline plugging pig claimed in claim 5 wherein said means operable in response to said differential fluid pressure comprises means defining an expandable volume adapted to receive fluid under pressure and including a member movable in response to expansion of said volume, means for admitting pipeline fluid under pressure to said expandable volume to move the movable member, means operatively connecting the movable member to said second spring means to store energy in said second spring means when said volume expands.

Claim 11

The pipeline plugging pig claimed in claim 6 wherein the means defining an expandable volume comprises a piston and cylinder mechanism, said means for admitting pipeline fluid under pressure admitting pipeline fluid under pressure to a region between the piston and cylinder to produce relative displacement therebetween.

Claim 12

A pipeline plugging pig comprising a body adapted to move through a pipeline, a plurality of arresting jaws carried by said body and movable together from withdrawn positions to extended positions in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for releasably sealing the interior of the pipeline to block fluid flow therethrough when the jaws are engaged with the interior wall of the pipeline, thereby to establish a differential fluid pressure between different portions of the body when fluid under pressure is in the pipeline, means including first spring means for moving said jaws to said extended position, restraining means for releasably holding the first spring means in an energy storage condition, thereby to hold the jaws in said withdrawn position, means selectively operable for releasing the restraining means to permit said first spring means to urge the jaws to said extended positions, second spring means adapted, when in its energy storage condition and in its relaxed condition, to exert a force greater than that exerted by said first spring means when in its energy storage condition, means rsponsive to said differential pressure for placing said second spring means in its energy storage condition, and means selectively operable, in the absence of said differential pressure, for releasing the second spring means from its energy storage condition and for actuating said means including first spring means for returning the first spring means to its energy storage condition and returning said jaws to said withdrawn position.

Claim 13

A pipeline plugging pig comprising a body adapted to move through a pipeline, a plurality of arresting jaws carried by said body and movable together from withdrawn positions to extended positions in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for releasably sealing the interior of the pipeline to block fluid flow therethrough when the jaws are engaged with the interior wall of the pipeline, thereby to establish a differential fluid pressure between different portions of the body when fluid under pressure is in the pipeline, means including first spring means for moving said jaws to said extended position, restraining means for releasably holding the first spring means in an energy storage condition, thereby to hold the jaws in said withdrawn position, means selectively operable for releasing the restraining means to permit said first spring means to urge the jaws to said extended positions, second spring means adapted, when in its energy storage condition and in its relaxed condition, to exert a force greater than that exerted by said first spring means when in its energy storage condition, means rsponsive to said differential pressure for placing said second spring means in its energy storage condition, and means selectively operable, in the absence of said differential pressure, for releasing the second spring means from its energy storage condition and for actuating said means including first spring means for returning the first spring means to its energy storage condition and returning said jaws to said withdrawn position.

Claim 14

A pipeline plugging pig comprising a body adapted to move through a pipeline, a plurality of arresting jaws carried by said body and movable between a withdrawn position and an extended position in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for releasably sealing the interior of the pipeline to block fluid flow therethrough when the jaws are engaged with the interior wall of the pipeline, thereby to establish a differential fluid pressure between different portions of the body when fluid under pressure is in the pipeline, first spring means having an energy storage condition and a relaxed condition, means linking the first spring means to said jaws for permitting the stored energy of the spring means to act on the linking means when the jaws are in said withdrawn position, restraining means for releasably restraining said linking means against moving said jaws to said extended position, selectively operable means for releasing the restraining means to permit the stored energy of the springs to act on the linking means and force the jaws to said extended position, second spring means having a stored energy condition and a relaxed condition, said second spring means, when in either of its conditions, exerting the first spring means when in its energy storage condition, means responsive to said differential fluid pressure for placing said second spring means in its energy storage condition, means selectively operable, in the absence of said differential pressure, for transferring stored energy from the second spring means to the first spring means to reset it in its stored energy condition and for returning the jaws to said withdrawn position.

Claim 15

A pipeline plugging pig comprising a body adapted to move through a pipeline, a plurality of arresting jaws carried by said body and movable between a withdrawn position and an extended position in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for releasably sealing the interior of the pipeline to block fluid flow therethrough when the jaws are engaged with the interior wall of the pipeline, thereby to establish a differential fluid pressure between different portions of the body when fluid under pressure is in the pipeline, first spring means having an energy storage condition and a relaxed condition, means linking the first spring means to said jaws for permitting the stored energy of the spring means to act on the linking means when the jaws are in said withdrawn position, restraining means for releasably restraining said linking means against moving said jaws to said extended position, selectively operable means for releasing the restraining means to permit the stored energy of the springs to act on the linking means and force the jaws to said extended position, second spring means having a stored energy condition and a relaxed condition, said second spring means, when in either of its conditions, exerting the first spring means when in its energy storage condition, means responsive to said differential fluid pressure for placing said second spring means in its energy storage condition, means selectively operable, in the absence of said differential pressure, for transferring stored energy from the second spring means to the first spring means to reset it in its stored energy condition and for returning the jaws to said withdrawn position.

Claim 16

A pipeline plugging pig comprising a body adapted to be received within and movable through a pipeline, a plurality of arresting jaws carried by said body and movable from first withdrawn positions to second extended positions in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for engaging the interior wall of the pipeline to block fluid flow within the pipeline when said jaws are engaged with the interior wall of the pipeline, whereby a differential fluid pressure is established at portions of said body when fluid under pressure is in the pipeline, first spring means operatively connected to said jaws for urging the jaws from said first to said second positions, means including latch means for holding said jaws in said first positions against the force of the first spring means, said latch means being operable in response to a first command to permit the jaws to be moved by the spring means to the second positions, thereby to engage the interior wall of the pipeline, a second set of spring means, means responsive to said differential fluid pressure for storing energy in said second set of springs when said pipeline is blockEd, means for releasably holding said second spring means in its stored energy condition irrespective of the differential fluid pressure at said portions of the body, means operable in response to a second command for releasing said holding means for permitting the second spring means to exert its stored energy on the jaws to move the jaws back to said first position, said latch means being operable to hold jaws in said first position until receipt of another first command.

Claim 17

A pipeline plugging pig comprising a body adapted to be received within and movable through a pipeline, a plurality of arresting jaws carried by said body and movable from first withdrawn positions to second extended positions in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for engaging the interior wall of the pipeline to block fluid flow within the pipeline when said jaws are engaged with the interior wall of the pipeline, whereby a differential fluid pressure is established at portions of said body when fluid under pressure is in the pipeline, first spring means operatively connected to said jaws for urging the jaws from said first to said second positions, means including latch means for holding said jaws in said first positions against the force of the first spring means, said latch means being operable in response to a first command to permit the jaws to be moved by the spring means to the second positions, thereby to engage the interior wall of the pipeline, a second set of spring means, means responsive to said differential fluid pressure for storing energy in said second set of springs when said pipeline is blockEd, means for releasably holding said second spring means in its stored energy condition irrespective of the differential fluid pressure at said portions of the body, means operable in response to a second command for releasing said holding means for permitting the second spring means to exert its stored energy on the jaws to move the jaws back to said first position, said latch means being operable to hold jaws in said first position until receipt of another first command.

Claim 18

A pipeline plugging pig comprising a body adapted to move through a pipeline, a plurality of arresting jaws carried by said body and movable together from withdrawn positions to extended positions in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for releasably sealing the interior of the pipeline to block fluid flow therethrough when the jaws are engaged with the interior wall of the pipeline, whereby a differential fluid pressure is established at different portions of the body when fluid under pressure is in said pipeline, a slidable sleeve member operatively connected to said jaws to move them from the withdrawn position to the extended position, first spring means operatively connected to said sleeve member for exerting a first force against sqid sleeve member when said jaws are in the withdrawn position and when the spring means is in its stored energy condition, latch means releasably engaging said sleeve member for holding said jaws in the withdrawn positions, latch control means operable in response to a first command for releasing the latch from engagement with said sleeve member to permit the first spring means to slide the sleeve member and move the jaws to said extended positions, a slidable cylinder coaxial with said sleeve means, said cylinder being slidable from a first position to a locking position, said cylinder supporting said latch means, thereby being in motion-restraining engageable with said sleeve when the cylinder is in its first position and said jaws are in said withdrawn position, second spring means operatively connected to said cylinder and adapted when in both its stored energy condition and its relaxed position to exert against said cylinder a force greater in magnitude than, and opposite in direction to, said first force exerted by said first spring means, means operable in response to said differential fluid pressure for sliding the cylinder to its locking position and in turn placing the second spring means in its stored energy condition, means cooperating with said latch means to releasably hold the cylinder in its locking position irrespective of differential fluid pressure at said portions of the body, said latch control means being operable in response to a second command to release said latch means from said cooperating means and again engage the latch means with said sleeve member, whereby upon equalization of fluid pressure at said portions of the body said second spring means may return the cylinder to its first position, return the jaws to said withdrawn positions, and return said first spring means to its stored energy condition.

Claim 19

A pipeline plugging pig comprising a body adapted to move through a pipeline, a plurality of arresting jaws carried by said body and movable together from withdrawn positions to extended positions in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for releasably sealing the interior of the pipeline to block fluid flow therethrough when the jaws are engaged with the interior wall of the pipeline, whereby a differential fluid pressure is established at different portions of the body when fluid under pressure is in said pipeline, a slidable sleeve member operatively connected to said jaws to move them from the withdrawn position to the extended position, first spring means operatively connected to said sleeve member for exerting a first force against sqid sleeve member when said jaws are in the withdrawn position and when the spring means is in its stored energy condition, latch means releasably engaging said sleeve member for holding said jaws in the withdrawn positions, latch control means operable in response to a first command for releasing the latch from engagement with said sleeve member to permit the first spring means to slide the sleeve member and move the jaws to said extended positions, a slidable cylinder coaxial with said sleeve means, said cylinder being slidable from a first position to a locking position, said cylinder supporting said latch means, thereby being in motion-restraining engageable with said sleeve when the cylinder is in its first position and said jaws are in said withdrawn position, second spring means operatively connected to said cylinder and adapted when in both its stored energy condition and its relaxed position to exert against said cylinder a force greater in magnitude than, and opposite in direction to, said first force exerted by said first spring means, means operable in response to said differential fluid pressure for sliding the cylinder to its locking position and in turn placing the second spring means in its stored energy condition, means cooperating with said latch means to releasably hold the cylinder in its locking position irrespective of differential fluid pressure at said portions of the body, said latch control means being operable in response to a second command to release said latch means from said cooperating means and again engage the latch means with said sleeve member, whereby upon equalization of fluid pressure at said portions of the body said second spring means may return the cylinder to its first position, return the jaws to said withdrawn positions, and return said first spring means to its stored energy condition.

Claim 20

A pipeline plugging pig comprising a body adapted to move through a pipeline, a plurality of arresting means carried by said body and movable together from a withdrawn position to an extended position in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for releasably sealing the interior of the pipeline to block fluid flow therethrough when the arresting means are engaged with the interior wall of the pipeline, whereby a differential fluid pressure is established at different portions of the body when fluid under pressure is in said pipeline, a slidable sleeve member disposed within said body and operativEly connected to said arresting means to move them between the withdrawn position and the extended position, first spring means operatively connected to said sleeve member for exerting a first force against said sleeve member when said arresting means are in the withdrawn position and when the spring means is in its energy storage condition, a restraining dog for releasably holding said sleeve in a first position to maintain the first spring means in its energy storage condition and said arresting means in said withdrawn position, said sleeve being operable to slide past said dog to a second position when the dog is in a sleeve-release position, the arresting means being in said extended position when the sleeve is in its second position, cam means for controlling the positioning of said restraining dog, motor means for controlling the positioning of the cam means to sequentially position said dog to a sleeve-holding position, then to said sleeve-release position, and then to a locking position in which said arresting means also is in said extended position, an axially slidable cylinder coaxial with said sleeve, said dog and cam means being mounted on said cylinder for movement therewith, means operable in response to said differential fluid pressure for sliding said cylinder from an initial position to a locked position in which said dog is out of restraining engagement with said sleeve, engaging means for engaging said dog when the odg is in said locking position and for holding the cylinder in a locked position irrespective of said differential pressure, second spring means operatively connected to said cylinder in a manner to be set to its energy storage condition when the cylinder is moved to its locked position, said dog being disengaged from the dog engaging means and re-engaging said sleeve in response to a predetermined movement of said motor, whereby said second spring means returns the cylinder to its initial position, returns the arresting means to said withdrawn position, and restores the first spring means to its energy storage condition.

Claim 21

A pipeline plugging pig comprising a body adapted to move through a pipeline, a plurality of arresting means carried by said body and movable together from a withdrawn position to an extended position in which they are displaced outwardly of the body for engaging the interior wall of said pipeline to arrest the movement of the body through the pipeline, means for releasably sealing the interior of the pipeline to block fluid flow therethrough when the arresting means are engaged with the interior wall of the pipeline, whereby a differential fluid pressure is established at different portions of the body when fluid under pressure is in said pipeline, a slidable sleeve member disposed within said body and operativEly connected to said arresting means to move them between the withdrawn position and the extended position, first spring means operatively connected to said sleeve member for exerting a first force against said sleeve member when said arresting means are in the withdrawn position and when the spring means is in its energy storage condition, a restraining dog for releasably holding said sleeve in a first position to maintain the first spring means in its energy storage condition and said arresting means in said withdrawn position, said sleeve being operable to slide past said dog to a second position when the dog is in a sleeve-release position, the arresting means being in said extended position when the sleeve is in its second position, cam means for controlling the positioning of said restraining dog, motor means for controlling the positioning of the cam means to sequentially position said dog to a sleeve-holding position, then to said sleeve-release position, and then to a locking position in which said arresting means also is in said extended position, an axially slidable cylinder coaxial with said sleeve, said dog and cam means being mounted on said cylinder for movement therewith, means operable in response to said differential fluid pressure for sliding said cylinder from an initial position to a locked position in which said dog is out of restraining engagement with said sleeve, engaging means for engaging said dog when the odg is in said locking position and for holding the cylinder in a locked position irrespective of said differential pressure, second spring means operatively connected to said cylinder in a manner to be set to its energy storage condition when the cylinder is moved to its locked position, said dog being disengaged from the dog engaging means and re-engaging said sleeve in response to a predetermined movement of said motor, whereby said second spring means returns the cylinder to its initial position, returns the arresting means to said withdrawn position, and restores the first spring means to its energy storage condition.