Abstract: Apparatus for inserting a flexible bag into the interior of a fluid transmission line to form a plug by filling the bag with a freezable liquid. The apparatus comprises a cylindrical frame member with a flange for mounting the apparatus on a saddle member attached to the transmission line. A first telescoping tubular member is mounted on the frame member and supports second and third telescoping tubular members and provides a cavity for storing the bag in a collapsed condition. The second tubular member is connected to the bag and is operable to eject the bag from the first tubular member into the transmission line interior. The third tubular member is operable to extend into the bag interior, includes a liquid conduit for filling the bag and includes conduits for circulating cooling or heating fluid within the interior of the third tubular member to form a heat exchanger for accelerating the freezing or thawing of the liquid within the bag.

Abstract: A flow stopping plug is formed in a conduit such as a fluid transmission pipeline by tapping a relatively small hole in the side of the pipe directly adjacent the desired location of the plug and inserting a flexible bag through the hole using a radially extendable bag insertion apparatus having a tube containing the bag initially in a collapsed or folded condition. The bag is connected to a conduit assembly which provides for filling the bag with water in the deployed position inside the pipe. After the bag is filled with water, a freezing process is carried out preferably using a cryogenic fluid which is circulated around the exterior of the pipe section directly adjacent to the bag. The conduit assembly connected to the bag may be placed in communication with a source of heating fluid for melting the ice plug formed within the bag after completion of the work process in connection with which the ice plug was deployed.

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.

Abstract: A flow stopping plug is formed in a conduit such as a fluid transmission pipeline by tapping a relatively small hole in the side of the pipe directly adjacent the desired location of the plug and inserting a flexible bag through the hole using a radially extendable bag insertion apparatus having a tube containing the bag initially in a collapsed or folded condition. The bag is connected to a conduit assembly which provides for filling the bag with water in the deployed position inside the pipe. After the bag is filled with water, a freezing process is carried out preferably using a cryogenic fluid which is circulated around the exterior of the pipe section directly adjacent to the bag. The conduit assembly connected to the bag may be placed in communication with a source of heating fluid for melting the ice plug formed within the bag after completion of the work process in connection with which the ice plug was deployed.

Abstract: Temporary plugs are formed in fluid transmission lines by circulating cryogenic fluid through a housing disposed on the exterior of the line to freeze a slug of liquid within the interior of the line. Flow of cryogenic fluid is controlled by sensing the temperature on the surface of the line and sensing the temperature in a housing vent line to indicate a predetermined maximum level of liquid. A temperature sensing and control apparatus is provided which includes dual temperature signal receiving and comparator circuits for operating control valves to open and close at minimum and maximum temperature set points. The control circuitry is operable to open and close the cryogenic fluid control valve in response to variation of the sensed temperature above or below the limit temperatures and in response to a change in temperature indicating an excess level of liquid cryogenic fluid in the chamber formed around the transmission line.

Abstract: Method for freezing a slug of water to form an ice plug in a section of a pipeline for hydrostatic testing purposes. The ice plug is formed by transferring thermal energy from the slug of water through the walls of the pipeline to a cryogenic cooling fluid such as liquid nitrogen. A section of the pipeline is filled with water and is enclosed by an insulated chamber. The chamber is filled with liquid nitrogen to form a pool around the pipeline. The liquid nitrogen is agitated by discharging a stream of nitrogen vapor through the pool. Heat exchange occurs as a result of heat transfer directly from the surface of the pipeline to the liquid nitrogen by the action of convection currents produced by the vigorous agitation of the liquid associated with the motion of the nitrogen vapor. In a preferred embodiment, the liquid nitrogen is diffused over the surface of the pipeline by means of a permeable layer of material which is easily wetted by the liquid nitrogen.

Abstract: Method and apparatus for installing and testing new pipelines or for testing, repairing or modifying existing pipelines without purging products from the line are disclosed. The method is carried out by selectively sealing the pipeline to prevent the flow of products by means of a pipeline freeze pig which features an expandable chamber which is filled with water. A section of fluid transmission line is sealed by positioning the freeze pig within the interior of the section and positioning a refrigeration unit around the exterior of the section enclosing the freeze pig. The water within the expandable enclosure is frozen by circulating a refrigerant through the refrigeration unit. The freeze pig is characterized by a resilient boot enclosure defining the expandable chamber which is secured to an elongated support member. The resilient boot is disposed between first and second flexible flange members which project radially for wiping engagement with the inner wall surface of the transmission line.

Abstract: Apparatus for freezing a slug of liquid to form an ice plug in a section of a pipeline for hydrostatic testing purposes. The ice plug is formed by transferring thermal energy from the slug of liquid through the walls of the pipeline to a cryogenic cooling fluid such as liquid nitrogen. A section of the pipeline is filled with liquid and is enclosed by an insulated housing which defines a cooling chamber. The chamber is filled with liquid nitrogen to form a pool around the pipeline. The liquid nitrogen is agitated by discharging a stream of liquid nitrogen or nitrogen vapor through the pool. Heat exchange occurs as a result of sensible heat transfer directly from the surface of the pipeline to the pool of liquid nitrogen. In a preferred embodiment, the liquid nitrogen is discharged uniformly over the surface of the pipeline as the chamber is filled by means of an insulated header which forms a part of the chamber housing.

Abstract: Apparatus for freezing a slug of water to form an ice plug in a section of a pipeline for hydrostatic testing purposes. The ice plug is formed by transferring thermal energy from the slug of water through the walls of the pipeline to a cryogenic cooling fluid such as liquid nitrogen. A section of the pipeline is filled with water and is enclosed by an insulated chamber. The chamber is filled with liquid nitrogen to form a pool around the pipeline. The liquid nitrogen is agitated by discharging a stream of nitrogen vapor through the pool. Heat exchange occurs as a result of heat transfer directly from the surface of the pipeline to the liquid nitrogen by the action of convection currents produced by the vigorous agitation of the liquid associated with the motion of the nitrogen vapor. In a preferred embodiment, the liquid nitrogen is diffused over the surface of the pipeline by means of a permeable layer of material which is easily wetted by the liquid nitrogen.