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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

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.

대표청구항 ▼

Apparatus for freezing a slug of liquid in a section of fluid transmission line comprising, in combination: a detachable housing having side portions for enclosing a section of the transmission line and end portions for engaging in sealing relation with opposite ends of the transmission line section

Apparatus for freezing a slug of liquid in a section of fluid transmission line comprising, in combination: a detachable housing having side portions for enclosing a section of the transmission line and end portions for engaging in sealing relation with opposite ends of the transmission line section, the side and end portions defining a cooling chamber when assembled around the transmission line, the cooling chamber being operable when filled by discharging cryogenic cooling fluid from spaced fluid distribution means, to confine a volume of said cryogenic cooling fluid in its liquid phase in intimate contact with the exterior surface of the section of transmission line enclosed by the housing, said detachable housing including inlet port means for admitting said cryogenic cooling fluid into the cooling chamber and exhaust port means for discharging said cryogenic cooling fluid out of the cooling chamber; and, said fluid distribution means including header means radially spaced from the transmission line and connected in fluid communication with the inlet port means for discharging said cryogenic cooling fluid into the cooling chamber and onto the enclosed surface of the transmission line.