Abstract: A sealing system for pressurized flanged joints such as for use in flow line systems, wellhead assemblies, vessel joints, etc. The flanges of the pressure containing system are formed to define circular seal grooves having oppositely tapered circular side walls. Ring seal means is provided having a cross-sectional configuration that tapers from a large dimension intermediate the axially extremities to smaller dimensions at each of the axial extremities, thus defining tapered seal surfaces for sealing engagement with respective side walls of the seal grooves. The ring seals may define a passage means communicating the axial extremities and may also define yieldable resilient sealing lips thus enabling radial yielding of the sealing lips as the tapered side walls of the seal grooves are urged into sealing engagement with the seal ring. The sealing lips of flexible nature may be defined by the ring seal at the axial extremities or at either of the inner and outer peripheries of the ring seal.

Abstract: A pressure balanced gate valve mechanism wherein a closed loop fluid interchange system interconnects the valve actuator stem area of the valve mechanism with the pressure balancing stem area and functions to accomodate volumetric changes to prevent the development of a hydraulic lock that might otherwise prevent or retard opening and closing movement of the valve mechanism. Internal back-face seating arrangements with combination metal-to-metal and elastomeric sealing elements establish seals between the valve stem and bonnet at one gate position and between the pressure balancing stem and valve body structure at the opposite gate position. An externally threaded portion of the valve bonnet is receivable within internally threaded receiver openings of a plurality of different actuator systems, including manual, mechanical, hydraulic and pneumatic actuator systems. The actuator systems are field interchangeable with the valve in service and under pressure.

Abstract: An expanding gate valve according to the present invention includes a gate system incorporating a pair of segments, one segment being formed to define opening cam surface means and the other segment being formed to define closed cam surface means. Spreader means is positioned in stationary manner within the valve chamber of the valve and includes opening and closing cam surface means that is engageable respectively with the cam surface means of the segments to achieve wedging, mechanically energized sealing enhancement between the segments and the valve seats as the gate segments reach the open or closed positions thereof during operation. The body structure of the valve is formed to define a valve chamber of generally cylindrical configuration within which may be located a pair of partially cylindrical seat carrier elements that properly position a pair of seat rings in relation to the valve body and the planar sealing surfaces of the gate segments.

Abstract: A sealing assembly for sealing the annulus between a wellhead and a casing hanger in which the assembly includes a recess for receiving a sealing element in which the recess includes a tapered surface and a tapered seat for coacting with a seal for setting the seal with a small setting force. A resilient sealing element is positioned in the recess and tapers downwardly and outwardly at a lower end. The sealing element is compressed in the recess to form a seal requiring only a low seating load and unseats with a low unseating load. An expandable metal ring is positioned in the lower outside portion of the sealing element to reduce extrusion of the element when set. A non-extrusive protective covering is positioned around the top, the outside and the outer portion of the bottom of the sealing element to protect it as it moves downhole in a well. Various seal modifications provide wedge actuated lip seals to increase the sealing area.