Abstract: The plug is formed of fibrous material held together by a wax binder in the form of a cylindrical body. The body is adapted to fit closely into the bore of an open-ended pipeline. The body has a reduced diameter inner end portion. A thick band of asphalt-base sealant is applied to the inner surface of the pipe at the location to be taken up by the reduced diameter portion. The vertical inner end surface of the plug is also coated with the sealant. When the plug is inserted into the line, its close fit holds it in place and the sealant seals across the bore. The plug functions to isolate residual hydrocarbon vapors in the line while a new section of pipe is tied in. The plug disintegrates when contacted with the subsequent oil flow.

Abstract: The tightener comprises a scissor clamp having first and second arms pivotally connected at their upper ends. At their lower ends, the arms are pivotally connected with the ends of a loop of chain that encircles a pair of semi-circular steel shells encircling a pipeline. The rod of a cylinder is pivotally connected to move the front arm toward the rear arm. The cylinder is positioned to operate generally perpendicularly relative to the arms.

Abstract: A process is provided for heat treating an annular martensitic heat-affected zone. The heat-affected zone is commonly created in the outer segment of a pipeline wall as a result of applying a circumferential fillet weld to the pipe. The embrittled zone creates a weakness in the pipe wall and it is therefore desirable to heat treat it. The heat-treating process is carried out in connection with a situation where the pipeline has an open end located close to the weld and a plug has been inserted in the bore of the line to isolate the main part of the line from the pipe end having the weld. An expandable and contractable insulating ring is inserted into the pipe bore. The ring is associated with a closure member which blanks and seals the open end of the pipe. The isolating plug is removed and the ring is positioned beneath the weld and expanded to abut the pipe wall. A final circumferential weld or bead is then applied to the existing weld, which causes heating of the martensitic zone.

Abstract: The vapor plug can be inserted into an open end of a pipeline. It comprises a hydraulic cylinder carrying a vertically disposed, elastic, resilient seal ring. The cylinder may be hydraulically actuated to expand the ring radially to seal the bore of the line. The hydraulic lines to and from the cylinder chamber may be blocked to lock the plug in the expanded mode. A plunger valve, responsive to pipeline pressure, controls a hydraulic fluid passage connecting the ends of the cylinder chamber. When the plunger valve is in the closed mode, it prevents fluid moving between the chamber ends. When the valve is moved by pipeline pressure to the open mode, fluid can move freely between the chamber ends, thereby permitting the ring seal to contract, to unseal the bore. The plug may then be pumped down the line and recovered at a pig trap.