Abstract: Methods and apparatus for sealing an aperture that provides fluid communication between a second and first chamber of a dual chamber orifice fitting. A sealing assembly comprises a closure member that is rotatably moveable between an open and closed position relative to the aperture. A secondary seal is disposed within a recessed portion on a sealing face of the closure member.

Abstract: Apparatus and methods for operating a dual chamber orifice fitting. The dual chamber orifice fitting comprises a body having a lower chamber and a top having an upper chamber. An aperture connects the upper chamber to the lower chamber. A closure member is pivotally mounted to the fitting and pivots about a first axis between a first position and a second position. A pivot arm is rotatably mounted to the body and engages the closure member so that rotation of the pivot arm about a second axis pivots said closure member about the first axis between the first and second positions.

Abstract: Apparatus and methods for operating a valve assembly for a dual chamber orifice fitting. The dual chamber orifice fitting comprises a body attached to a top. A passageway connects between the body and the top and allows an orifice plate carrier to move between the body and the top. A valve assembly selectably closes the passageway. Embodiments of the valve assembly comprise a seat, a plug, and a stem. The valve assembly has a closed position, wherein a curved outer surface of the plug sealingly engages a curved sealing surface of the seat and prohibits fluid communication through the passageway. The valve assembly has an open position, wherein a plug aperture is aligned with a seat aperture to allow the orifice plate carrier to move through the passageway.

Abstract: A dual chamber orifice fitting, including a body with a lower chamber in fluid communication with a pipeline and a top with an upper chamber in fluid communication with the lower chamber. A valve assembly closes to hydraulically isolate the upper chamber from the lower chamber and opens to allow an orifice plate carrier to move between the chambers. When the orifice plate carrier is in the lower chamber is can be aligned with the flowbore of the pipeline. The orifice plate carrier can be removed from the fitting through the upper chamber. In the preferred embodiments, at least one of either the upper or lower chambers has a non-rectangular cross-section. The body and top may also have a curved outer surface to accommodate the non-rectangular cross-section of the interior chambers.

Abstract: Methods and apparatus for positioning an orifice plate within a body having a straight flowbore. One embodiment includes a carrier supporting the orifice plate and a drive member operable to engage the carrier and move the carrier along a first axis perpendicular to the flowbore. The drive member is also operable to limit the movement of the carrier along a second axis perpendicular to the flowbore and perpendicular to the first axis. A pin is operable to engage the carrier so as to limit movement along the first axis.