Pipeline pig stopper

Claim 2

For use in an elongated tubular member, a releasable plug comprising a rigid tubular core enclosing a pressure sealed chamber, expansible sealing means mounted on said core in fluid communication with said chamber, inlet valve means mounted by the core for pressuring the chamber and expanding the sealing means into sealing engagement with the tubular member, mechanical gripping means mounted by the core and biased into engagement with the tubular member for holding the core axially fixed to the tubular member, cam means responsive to displacement within the chamber for disengaging the mechanical gripping means from the tubular member, and control means connected to the cam means for simultaneous displacement of the cam means and venting of the pressurized chamber to release the gripping means and deflate the expansible sealing means.

Claim 3

The combination of claim 1 wherein said expansible sealing means comprises a pair of annular sealing tubes disposed on the core axially spaced from each other by the gripping means, and rigid fittings secured to the core anchoring the tubes thereto, said fittings having passages therein establishing fluid communication between the tubes and the chamber.

Claim 4

The combination of claim 2 wherein said gripping means comprises a plurality of retainers axially fixed to the core in equal circumFerentially spaced relation to each other, a surface engaging element slidably mounted by each of said retainers projecting radially from the core, link means operatively connected to each of the elements within the chamber for engagement by the cam means, and spring means within each retainer urging each of the elements radially outward.

Claim 5

The combination of claim 3 wherein said cam means comprises an axial cam member having an intermediate profile portion engaged by the gripping means in an extended position thereof and axial end detent portions engageable by the gripping means to yieldably hold the same in a retracted position.

Claim 6

The combination of claim 4 wherein said control means includes an actuating shaft connected to the cam means within the chamber, slide bearing means mounted by the core for slidably mounting the actuating shaft and sealing the chamber, a stop element mounted by the actuating shaft and engageable with the slide bearing means to limit movement of the cam means between at least two operative positions, said shaft having a vent passage formed therein externally venting the chamber when the stop element engages the slide bearing means in one of the operative positions of the cam means.

Claim 7

The combination of claim 1 wherein said gripping means comprises a plurality of retainers axially fixed to the core in equal circumferentially spaced relation to each other, a surface engaging element slidably mounted by each of said retainers projecting radially from the core, link means operatively connected to each of the elements within the chamber for engagement by the cam means, and spring means within each retainer urging each of the elements radially outward.

Claim 8

The combination of claim 1 wherein said cam means comprises an axial cam member having an intermediate profile portion engaged by the gripping means in an extended position thereof and axial end detent portions engageable by the gripping means to yieldably hold the same in a retracted position.

Claim 9

The combination of claim 1 wherein said control means includes an actuating shaft connected to the cam means within the chamber, slide bearing means mounted by the core for slidably mounting the actuating shaft and sealing the the chamber, a stop element mounted by the actuating shaft and engageably with the slide bearing means to limit movement of the cam means between at least two operative positions, said shaft having a vent passage formed therein externally venting the chamber when the stop element engages the slide bearing means in one of the operative positions of the cam means.

Claim 10

For use in an elongated tubular member, a releasable plug comprising a rigid tubular core enclosing a pressure sealed chamber, expansible sealing means mounted on said core in fluid communication with said chamber, inlet valve means mounted by the core for pressurizing the chamber and expanding the sealing means into sealing engagement with the tubular member, mechanical gripping means, operating means mounted within the chamber for disengaging said mechanical gripping means and control means connected to the operating means for actuation thereof and to vent the pressurized chamber for deflating the sealing means.

Claim 11

For use in an elongated tubular member, a releasable plug comprising a rigid tubular core enclosing a pressure sealed chamber, expansible sealing means mounted on said core in fluid communication with said chamber, inlet valve means mounted by the core for pressurizing the chamber and expanding the sealing means into sealing engagement with the tubular member, mechanical gripping means, operating means mounted within the chamber for disengaging said mechanical gripping means and control means connected to the operating means for actuation thereof and to vent the pressurized chamber for deflating the sealing means.

Claim 12

For use in an elongated tubular member, a releasable plug comprising a rigid tubular core enclosing a pressure-sealed chamber, expansible sealing means mounted on said core in fluid communication with said chamber, inlet valve means mounted by the core for pressurizing the chamber and expanding the sealing means into sealing engagement with the tubular member, mechanical gripping means, operating means mounted within the chamber for disengaging said mechanical gripping means and control means connected to the operating means for actuation thereof and to vent the pressurized chamber for deflating the sealing means, said control means including an actuating shaft connected to the operating means within the chamber, slide bearing means mounted by the core for slidably mounting the actuating Shaft and sealing the chamber, a stop element mounted by the actuating shaft and engageable with the slide bearing means to limit movement of the operating means between at least two operative positions, said shaft having a vent passage formed therein externally venting the chamber when the stop element engages the slide bearing means in one of the operative positions of the operating means.

Claim 13

For use in an elongated tubular member, a releasable plug comprising a rigid tubular core enclosing a pressure-sealed chamber, expansible sealing means mounted on said core in fluid communication with said chamber, inlet valve means mounted by the core for pressurizing the chamber and expanding the sealing means into sealing engagement with the tubular member, mechanical gripping means, operating means mounted within the chamber for disengaging said mechanical gripping means and control means connected to the operating means for actuation thereof and to vent the pressurized chamber for deflating the sealing means, said control means including an actuating shaft connected to the operating means within the chamber, slide bearing means mounted by the core for slidably mounting the actuating Shaft and sealing the chamber, a stop element mounted by the actuating shaft and engageable with the slide bearing means to limit movement of the operating means between at least two operative positions, said shaft having a vent passage formed therein externally venting the chamber when the stop element engages the slide bearing means in one of the operative positions of the operating means.

Claim 14

For use in an elongated tubular member, a releasable plug comprising a core, expansible sealing means mounted on the core for engagement with the tubular member when pressurized, mechanical gripping means mounted on the core for anchoring the same to said tubular member, and displaceable means movably mounted by the core for simultaneously deflating the sealing means and retracting the gripping means from engagement with the tubular member.

Claim 15

For use in an elongated tubular member, a releasable plug comprising a core, expansible sealing means mounted on the core for engagement with the tubular member when pressurized, mechanical gripping means mounted on the core for anchoring the same to said tubular member, and displaceable means movably mounted by the core for simultaneously deflating the sealing means and retracting the gripping means from engagement with the tubular member.