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.Butterfly Valves 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.Forged Steel Valves The valve body is so constructed that the downstream plate thereof may be secured in assembly with the upstream plate by bolts extending through an upstream pipe flange, thereby allowing the valve mechanism to be employed in the absence of any abutting relationship with a downstream pipe flange.BALANCING VALVES The pressure enhancing feature of the annular sealing element also induces pressure enhanced sealing about a valve stem and trunnion that support the butterfly element for rotation within the flow passage of the valve. A high pressure butterfly valve having pressure enhanced sealing, said butterfly valve comprising: a valve body being connectable to a flow line and being formed to define a flow passage; said valve body defining an annular seal chamber having an annular seal aperture of smaller dimension than the dimension of said seal chamber; valve stem means being rotatably supported by said valve body and having a valve operating portion thereof extending externally of said valve body, said valve stem means having a butterfly disc engaging portion disposed within said flow passage; a butterfly element being positioned within said flow passage and being supported for rotation between open and closed positions by said valve stem means, said butterfly element having an outer periphery that is positioned in juxtaposed relation with said annular seal aperture in the closed position of said butterfly element; an annular sealing element being located within said seal chamber and being formed to define an annular pressure receiving base portion and a seal portion, said seal portion extending through said annular seal aperture into said flow passage and having sealing engagement with the periphery of said butterfly element in the closed position of said butterfly element; passage means being defined by said valve body and communicating fluid pressure from said flow passage upstream of said butterfly element to said seal chamber, said pressure receiving base portion defining an annular groove that faces upstream and receives fluid pressure from said passage means; said sealing portion of said sealing element being urged toward said periphery of said valve disc responsive to pressure acting within said annular groove; and stem seal means being formed integrally with said sealing element and being in sealing engagement with said valve stem means, the sealing ability of said stem seal means also being enhanced by fluid pressure within said annular groove. A preferred embodiment of the present invention may conveniently take the form of a two-piece split valve body that is adapted to be interposed between the flanges of a pair of flanged pipe sections and which is maintained in position by bolts that extend both through the flanges and through mating bolt apertures formed in the valve body construction. The split valve body is defined by a pair of body plates that are of generally circular disc-like configuration and are formed to define semi-cylindrical stem and trunnion receptacles that define stem and trunnion passages when the body sections are placed in assembly. The annular disc-like body plates are also machined to define annular grooves that interfit to define an annular seal chamber within which may be received an annular sealing element to establish sealing about the periphery of a butterfly valve disc in the closed position thereof. An annular sealing portion of the sealing element extends through an internal groove defined by the valve body construction for engagement with the sealing surface of the disc. The configuration of the groove and sealing element is such that a major base portion of the sealing element is retained within an enlarged seal chamber and is prevented by annular shoulders from being extruded into the flow passage by the pressure of the fluid controlled by the valve. At least one of the valve body plates is formed to define pressure-introducing passages that conduct upstream line pressure through the valve body construction into the annular seal chamber, thereby allowing line pressure to act upon the sealing element in such manner as to urge the sealing portion thereof into sealing engagement with the periphery of the valve disc. As pressure increases, the sealing ability of the sealing element is enhanced in direct proportion thereto. The base portion of the sealing element is of generally U-shaped cross-sectional configuration defining an annular cup that faces upstream and receives the pressure introduced through the pressure introduction passages. An outer peripheral portion of the cup-like U-shaped base portion of the sealing element cooperates with each of the valve body plates to define seals therewith and prevent any leakage in the joint established between the assembled valve body plates.

MORE NEWS