Foldable, Double-Block and Bleed Plugging Tool

摘要

An isolation tool for temporarily isolating a section of pipeline has foldable semi-circular sealing element halves that, when unfolded, combine to form a primary and secondary sealing element. The element halves unfold by rotating an inner bar about an outer bar. A bleed hole permits any fluid which leaks past the primary sealing element and into the annular space between the sealing elements to enter a longitudinal bleed passageway located within the tool itself, thereby eliminating the need for a bleed port or valve to be welded onto the pipeline. The tool, which is pressure balanced, is well adapted for use in applications in which the lateral access opening is significantly smaller in diameter than the pipe diameter.

主权项

1. An isolation tool for temporarily isolating a section of pipeline, the isolation tool comprising:
an inner bar and an outer bar, the inner bar being arranged for rotation about the outer bar; a longitudinal bleed passageway located within the inner bar; a set of spaced-apart semi-circular sealing element halves connected to each bar; a plate located between the semi-circular sealing element halves and having a bleed hole; a longitudinal bleed passageway located within at least one of the inner bar and the outer bar and in communication with the bleed hole;wherein a circular primary sealing element and a secondary sealing element is formed as the inner bar rotates about the outer bar to bring each set of spaced-apart semi-circular sealing element halves into engagement with the other.