Method and apparatus for forming a temporary plug in a submarine conduit
First Claim
1. A method for forming a temporary plug in a submarine fluid pipeline or the like comprising the steps of:
- providing a quantity of freezable liquid at a predetermined location within said pipeline;
providing a generally cylindrical housing having an interior portion forming an annular chamber between the exterior surface of said pipeline and said housing when said housing is placed on said pipeline, said housing being longitudinally divided into at least two sections and having means thereon for conducting fluid to and from said chamber, said means including a plurality of conduits and respective remotely operable valves connected to respective ones of said conduits;
providing a pressure sensing element disposed on said housing for measuring the fluid pressure within said chamber;
installing said housing around the exterior of said pipeline at said predetermined location on said pipeline;
connecting at least one of said conduits to a source of low temperature fluid;
remotely controlling said valves to conduct low temperature fluid to said chamber to freeze said quantity of liquid to form said plug; and
controlling the fluid pressure within said chamber in accordance with the pressure of the environment around the exterior of said housing.
6 Assignments
0 Petitions
Accused Products
Abstract
Fluid transmission lines in a submarine or hazardous environment are provided with substantially fluid tight seals by the formation of a temporary ice plug within the interior of the line using a housing forming a cryogenic fluid circulation chamber installed around the exterior of the line. Remote controlled valves are interposed in separate conduits for supplying fluid to chambers formed within the housing, venting fluid vapor from the chambers, recirculating liquid cryogenic fluid back to a reservoir and for purging sea water from the chambers formed by the housing. The remote controlled valves are preferably controlled from a service vessel on the water surface or from within a submarine habitat. Conduit assemblies are provided with self closing quick disconnect connector assemblies whereby the service vessel containing a source of cryogenic fluid and a control station may abandon the work site during heavy sea conditions. The operating sequence for installation and freezing of the temporary plug includes installation of the housing forming the fluid circulation chamber by skilled divers followed by purging of sea water from within the chamber using compressed air or cryogenic fluid in gaseous form. Cryogenic fluid pressure within the chamber formed by the housing is preferably maintained at a pressure slightly greater than the hydrostatic sea water pressure at the location of the housing on the transmission line so as to minimize stress on the housing structure and to minimize the chance of leakage of sea water into the housing chambers.
30 Citations
24 Claims
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1. A method for forming a temporary plug in a submarine fluid pipeline or the like comprising the steps of:
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providing a quantity of freezable liquid at a predetermined location within said pipeline; providing a generally cylindrical housing having an interior portion forming an annular chamber between the exterior surface of said pipeline and said housing when said housing is placed on said pipeline, said housing being longitudinally divided into at least two sections and having means thereon for conducting fluid to and from said chamber, said means including a plurality of conduits and respective remotely operable valves connected to respective ones of said conduits; providing a pressure sensing element disposed on said housing for measuring the fluid pressure within said chamber; installing said housing around the exterior of said pipeline at said predetermined location on said pipeline; connecting at least one of said conduits to a source of low temperature fluid; remotely controlling said valves to conduct low temperature fluid to said chamber to freeze said quantity of liquid to form said plug; and controlling the fluid pressure within said chamber in accordance with the pressure of the environment around the exterior of said housing. - View Dependent Claims (11)
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2. A method for forming a temporary plug in a submarine fluid pipeline or the like comprising the steps of:
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providing a quantity of freezable liquid at a predetermined location within said pipeline; providing a hyperbaric habitat having fluid conduit connector means thereon for connecting conduits exterior of said habitat to conduits within said habitat; providing a generally cylindrical housing having an interior portion forming an annular chamber between the exterior surface of said pipeline and said housing when said housing is placed on said pipeline, said housing being longitudinally divided into at least two sections and having means thereon for conducting fluid to and from said chamber, said means including a first set of conduits and respective remotely operable valves connected to respective ones of said conduits of said first set; installing said habitat around said pipeline at said predetermined location and purging water from the interior of said habitat; installing said housing around the exterior of said pipeline and within said habitat at said predetermined location; connecting said first set of conduits to said connector means; providing a second set of conduits and connecting said second set to said connector means on the exterior of said habitat, connecting one of said conduits of said second set to a source of low temperature fluid; remotely controlling said valves to conduct low temperature fluid to said chamber to freeze said quantity of liquid to form said plug; and venting fluid vapor from said chamber to the atmosphere above the water surface.
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3. A method for forming a temporary plug in a submarine fluid pipeline or the like comprising the steps of:
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providing a quantity of freezable liquid at a predetermined location within said pipeline, at which location said pipeline is exposed directly to sea water; providing a generally cylindrical housing having an interior portion forming an annular chamber between the exterior surface of said pipeline and said housing when said housing is placed on said pipeline, said housing being longitudinally divided into at least two sections and having means thereon for conducting fluid to and from said chamber, said means including a plurality of conduits and respective remotely operable valves connected to respective ones of said conduits; providing a plurality of elongated flexible conduits including connector means at opposite ends thereof; providing signal conducting means for said valves for controlling said valves to open and close; carrying said housing from the water surface to said predetermined location in at least two sections; installing said housing around the exterior of said pipeline at said predetermined location and in sealing relationship to said pipeline to form said chamber; connecting said flexible conduits at one end to respective ones of said remotely operable valves; connecting at least one of said flexible conduits at said opposite end thereof to said source of low temperature fluid; operating first and second ones of said valves to open; supplying pressure gas to said chamber through said first valve to purge water from said chamber; closing said second valve to prevent reentry of water into said chamber; and remotely controlling said valves to conduct low temperature fluid to said chamber to freeze said quantity of liquid to form said plug. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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12. In an apparatus for forming a temporary plug in a submarine fluid transmission line by freezing a quantity of liquid at a predetermined location within said transmission line;
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a housing comprising at least two housing sections formed in such a way as to provide for removably mounting said housing around the exterior of said transmission line at said predetermined location to form a chamber around the exterior of said transmission line, first and second fluid conduits in communication with said chamber in said housing, first and second power operated valves connected to said first and second conduits, respectively, for controlling the flow of fluid through said conduits and said chamber, first connector means for releasably connecting said conduits to a source of low temperature fluid, said source comprising a reservoir, and a pump connected to said reservoir for conducting fluid to said chamber by way of said conduit, said housing including a third conduit in communication with said chamber and a third valve in said conduit for conducting water out of said chamber to purge said chamber after installation of said housing around said transmission line; an elongated conduit assembly including at least two separate supply and return conduits and second connector means for releasably connecting said reservoir to said chamber by way of said conduit assembly and said first and second connector means for circulating low temperature fluid through said chamber to freeze said liquid to form said plug; and means for supplying pressure gas through one of said first and second conduits to purge water out of said chamber by way of said third valve and said third conduit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. In an apparatus for forming a temporary plug in a submarine fluid transmission line by freezing a quantity of liquid at a predetermined location within said transmission line;
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a housing comprising at least two housing sections formed in such a way as to provide for removably mounting said housing around the exterior of said transmission line at said predetermined location to form a chamber around the exterior of said transmission line, first and second fluid conduits in communication with said chamber in said housing, first and second power operated valves connected to said first and second conduits, respectively, for controlling the flow of fluid through said conduits and said chamber, first connector means for releasably connecting said conduits to a source of low temperature fluid, said source comprising a reservoir, and a pump connected to said reservoir for conducting fluid to said chamber by way of said conduits; an elongated conduit assembly including at least two separate supply and return conduits and second connector means for releasably connecting said reservoir to said chamber by way of said conduit assembly and said first and second connector means for circulating low temperature fluid through said chamber to freeze said liquid to form said plug; and means for supplying pressure gas from said source of low temperature fluid for purging water out of said chamber including a pressure gas supply circuit in communication with said reservoir, said circuit including a heat exchanger for heating said low temperature fluid to convert said fluid to a gaseous state, a compressor in said circuit for compressing said gas, and valve means for switching said compressor into communication with one of said first and second conduits for conducting pressure gas to said chamber. - View Dependent Claims (23, 24)
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Specification