Pressurized pipeline pigs

Claim 2

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least a front fluid pressure expandable plug and a rear fluid pressure expandable plug, each plug being adapted to restrain fluid flow thereacross, each plug having a deformable wall formed of resilient material and defining an external peripheral surface, said surface being expandable in response to fluid pressure in said plug to provide a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; coupling means adapted to securely fasten said plugs to each other and to maintain said plugs in longitudinal spaced apart relationship whereby a drying chamber is defined by the inner volume of said pipe confined between said plugs; said pig when inserted into said pipe divides said pipe into a downstream section in front of said front plug, an upstream section in rear of said rear plug, and into said drying chamber; said coupling means including fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said drying chamber on one hand, and between said drying chamber and said downstream section on the other hand, whereby said fluid pressure gradient is established for propelling said pig through said pipe.

Claim 3

The pig as recited in claim 1 wherein said fluid communication means between said drying chamber and said downstream section of said pipe include liquid-extracting means for extracting liquids from said drying chamber and ejecting them into said downstream section.

Claim 4

The pig as recited in claim 2 wherein said liquid extracting means include a siphon tube, and siphon tube orientation means for orienting said siphon tube in a downwardly direction.

Claim 5

The pig as recited in claim 3 wherein said siphon tube orientation means include a swivel rotatably coupled to said coupling means.

Claim 6

The pig as recited in claim 1 wherein said coupling means include a hollow shaft in fluid communication with said fluid communication means.

Claim 7

The pig as recited in claim 1 wherein said fluid communication means further include fluid discharge means positioned in front of said front plug facing said downstream section.

Claim 8

The pig as recited in claim 6 wherein said fluid discharge means have an orientation to allow said pig to rotate inside said pipe in response to rotational forces generated by said fluid discharge means.

Claim 9

The pig as defined in claim 6 wherein said fluid discharge means cause the fluids contained in said downstream section in front of said front plug to become stirred up thereby facilitating the removal of any solids in front of said front plug.

Claim 10

The pig as recited in claim 1 wherein each plug includes a fluid pressure expaNdable tire mounted on a rim.

Claim 11

The pig as recited in claim 4 wherein said rotatably mounted swivel includes a ballast weight.

Claim 12

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least a front plug and a rear plug, each plug being adapted to restrain fluid flow thereacross, each plug having a wall defining an external peripheral surface, said wall providing a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; coupling means adapted to fasten said plugs to each other and to maintain said plugs in longitudinal spaced-apart relationship whereby a drying chamber is defined by the inner volume of said pipe confined between said plugs; said pig when inserted into said pipe divides said pipe into a downstream section in front of said front plug, an upstream section in rear of said rear plug, and into said drying chamber; said coupling means including fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said drying chamber on one hand, and between said drying chamber and said downstream section on the other hand, whereby said fluid pressure gradient is established for propelling said pig through said pipe; and liquid pickup means responsive to said fluid pressure gradient between said drying chamber and said downstream section for removing liquids from said drying chamber.

Claim 13

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least a front plug and a rear plug, each plug being adapted to restrain fluid flow thereacross, each plug having a wall defining an external peripheral surface, said wall providing a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; coupling means adapted to fasten said plugs to each other and to maintain said plugs in longitudinal spaced-apart relationship whereby a drying chamber is defined by the inner volume of said pipe confined between said plugs; said pig when inserted into said pipe divides said pipe into a downstream section in front of said front plug, an upstream section in rear of said rear plug, and into said drying chamber; said coupling means including fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said drying chamber on one hand, and between said drying chamber and said downstream section on the other hand, whereby said fluid pressure gradient is established for propelling said pig through said pipe; and liquid pickup means responsive to said fluid pressure gradient between said drying chamber and said downstream section for removing liquids from said drying chamber.

Claim 14

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least a front plug and a rear plug, each plug being adapted to restrain fluid flow thereacross, each plug having a deformable wall formed of resilient material and defining an external peripheral surface, said surface providing a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; coupling means adapted to securely fasten said plugs to each other and to maintain said plugs in longitudinal spaced apart relationship whereby a drying chamber is defined by the inner volume of said pipe confined between said plugs; said pig when inserted into said pipe divides said pipe into a downstream section in front of said front plug, an upstream section in rear of said rear plug, and into said drying chamber; said coupling means including fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said drying chamber on one hand, and between said drying chamber and said downstream section on the other hand, whereby said fluid pressure gradient is established for propelling said pig through said pipe; and said coupling means including liquid pickup means comprising a swivel rotatably mounted on said coupling means and a siphon tube coupled to said swivel for picking up liquids from said drying chamber and expelling them into said downstream section.

Claim 15

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least a front plug and a rear plug, each plug being adapted to restrain fluid flow thereacross, each plug having a deformable wall formed of resilient material and defining an external peripheral surface, said surface providing a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; coupling means adapted to securely fasten said plugs to each other and to maintain said plugs in longitudinal spaced apart relationship whereby a drying chamber is defined by the inner volume of said pipe confined between said plugs; said pig when inserted into said pipe divides said pipe into a downstream section in front of said front plug, an upstream section in rear of said rear plug, and into said drying chamber; said coupling means including fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said drying chamber on one hand, and between said drying chamber and said downstream section on the other hand, whereby said fluid pressure gradient is established for propelling said pig through said pipe; and said coupling means including liquid pickup means comprising a swivel rotatably mounted on said coupling means and a siphon tube coupled to said swivel for picking up liquids from said drying chamber and expelling them into said downstream section.

Claim 16

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least one plug adapted to restrain fluid flow thereacross, said plug having a deformable wall formed of resilient material and defining an external peripheral surface, said surface providing a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; said plug when inserted into said pipe divides said pipe into a downstream section in front of said plug, and an upstream section in rear of said plug; fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said downstream section, whereby said fluid pressure gradient is established for propelling said pig through said pipe; and said fluid communication means including liqUid pickup means comprising a swivel rotatably mounted on said fluid communication means and a siphon tube coupled to said swivel for picking up fluids from said upstream section and expelling them into said downstream section.

Claim 17

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least one plug adapted to restrain fluid flow thereacross, said plug having a deformable wall formed of resilient material and defining an external peripheral surface, said surface providing a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; said plug when inserted into said pipe divides said pipe into a downstream section in front of said plug, and an upstream section in rear of said plug; fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said downstream section, whereby said fluid pressure gradient is established for propelling said pig through said pipe; and said fluid communication means including liqUid pickup means comprising a swivel rotatably mounted on said fluid communication means and a siphon tube coupled to said swivel for picking up fluids from said upstream section and expelling them into said downstream section.

Claim 18

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least one plug adapted to restrain fluid flow thereacross, said plug having a deformable wall formed of resilient material and defining an external peripheral surface, said surface providing a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; said plug when inserted into said pipe divides said pipe into a downstream section in front of said plug, and an upstream section in rear of said plug; fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said downstream section, whereby said fluid pressure gradient is established for propelling said pig through said pipe; said fluid communication means including liquid pickup means comprising a siphon tube for picking up fluids from said upstream section and expelling them into said downstream section; siphon tube orientation means for orienting said siphon tube in a downwardly direction.

Claim 19

A pipe line pig adapted to become propelled through a pipe by a fluid pressure gradient comprising: at least one plug adapted to restrain fluid flow thereacross, said plug having a deformable wall formed of resilient material and defining an external peripheral surface, said surface providing a movable seal between said surface and the adjacently surrounding portion of the inner cylindrical wall of said pipe; said plug when inserted into said pipe divides said pipe into a downstream section in front of said plug, and an upstream section in rear of said plug; fluid communication means for establishing fluid communication at least in the direction of fluid flow between said upstream section and said downstream section, whereby said fluid pressure gradient is established for propelling said pig through said pipe; said fluid communication means including liquid pickup means comprising a siphon tube for picking up fluids from said upstream section and expelling them into said downstream section; siphon tube orientation means for orienting said siphon tube in a downwardly direction.