Abstract: A mechanism is provided for torch cutting openings in pipes wherein the openings are dimensioned according to the size of other pipes to be connected by welding at the opening. The mechanism comprises a frame structure which is adapted to be secured in immovable relation to the pipe in which the opening is to be cut and wherein the frame structure supports locator means which establishes an axis of rotation relative to the pipe about which an opening is to be cut. The apparatus incorporates a pipe contour tracking mechanism which is efficiently adjusted for the size of the pipe opening to be cut and the size of the pipe in which the opening is to be cut. For each 360.degree. rotation of the cutting torch, the pipe contour tracking mechanism induces two-cycle linear oscillation of the torch, thus causing the cutting tip of the torch to be maintained in accurately spaced relation with the surface of the pipe as the torch is revolved 360.degree. about its axis of rotation during the hole cutting operation.

Abstract: A high-pressure butterfly valve having pressure enhanced sealing which comprises a valve body defined by a pair of interfitting body plates that are retained in assembly by bolts that also secure the valve mechanism into a flow line. The interfitting valve plates also cooperate to define a seal recess within which is received annular sealing means that provide a peripheral seal about a butterfly disc that is rotatably supported within a flow passage defined by the valve body plates. The annular sealing means also includes a pressure-responsive portion that is energized by pressure upstream of the butterfly element and which is directly responsive to pressure to urge the sealing portion thereof into sealing engagement with the periphery of the butterfly element.

Abstract: A high-pressure butterfly valve having pressure enhanced sealing which comprises a valve body defined by a pair of interfitting body plates that are retained in assembly by bolts that also secure the valve mechanism into a flow line. The interfitting valve plates also cooperate to define a seal recess within which is received an annular sealing element that provides a peripheral seal about a butterfly disc that is rotatably supported within a flow passage defined by the valve body plates. The annular sealing element also includes a pressure-responsive portion that is energized by pressure upstream of the butterfly element and which is directly responsive to pressure to urge the sealing portion thereof into sealing engagement with the periphery of the butterfly element.