Abstract: A top entry ball valve comprises a housing having an interior cavity sufficiently large to receive a conventional ball and conventional seat rings through an opening in the housing. After the ball/seat package has been inserted into the cavity, a cam arrangement is used to axially load the seat rings. The cam arrangement comprises a pair of circular cams, each having an undulating annular surface, which are disposed in the housing cavity adjacent one of the seat rings with the respective undulating annular surfaces of the cams being in closely adjacent facing relation to one another. After assembly of the valve, one of the circular cams is rotated relative to the other cam to vary the rotational positions of the undulating annular surfaces relative to one another thereby to vary the axial positions of the circular cams relative to one another and relative to the ball and seat rings.

Abstract: A ball valve having improved inherent rangeability comprises a floating ball of conventional design that is rotatable through substantially 90.degree. between a pair of seats respectively located adjacent the upstream and downstream sides of the valve within a valve housing. At least one of the seats is a one-piece lubricant-impregnated metal seat configured to provide a concave central surface portion that makes full-face direct sealing contact with the ball, and which defines multiple spaced holes that extend through the seat to increase the fluid-to-metal contact of fluid passing through the seat thereby to reduce the pressure between the upstream and downstream sides of the valve. The pattern of holes may be such as to cause the valve to exhibit an equal percentage of flow characteristic for at least a portion of the ball rotation and/or a linear flow characteristic for at least a portion of the ball rotation.

Abstract: A ball valve of the type comprising a housing having a ball mounted for 90.degree. rotation therein between open and closed valve positions utilizes a ball whose exterior surface is shaped to define two noncoaxial hemispherical surface portions of like size and shape that are integrated with one another and offset from one another along a plane that is oriented at substantially 45.degree. to an axially directed bore in the ball. The hemispherical surface portions of the ball are in touching engagement with a pair of annular seat rings in the housing in the open position of the valve, and engage the seat rings with increasing force as the ball is rotated from the open position to the closed position of the valve.

Abstract: A valve seat for ball valves comprises a ring-shaped or annular body fabricated of sintered metal particles having interparticulate spaces which are substantially completely filled with graphite. The seat is fabricated by pumping a dispersion of colloidal graphite in a liquid carrier through the matrix of a preformed ring-shaped sintered metal body, thereafter heating the body to drive off any portion of the liquid carrier which remains in the interparticulate spaces of the body, and then coining the body to collapse any voids which remain in the body and to mechanically bind into the body the graphite which has been trapped in said interparticulate spaces during the pumping step.

Abstract: Apparatus for generating linear motion comprises a body on one end of which is mounted a cylinder. A piston in the cylinder is joined to an actuating beam extending into the body. The actuating beam has moving surfaces that cooperate with fixed surfaces in the body to define a linear bearing. Fluid under pressure is introduced through a duct in the body to a port in the fixed surface of the linear bearing. It enters the space in the cylinder above the piston via a port in a moving surface of the actuating beam which leads to a duct in the actuating beam that opens through the crown of the piston. A resilient sealing member between the fixed and moving surface of the linear bearing maintains fluid-tight communication between the fixed and movable part over their range of relative movement. The actuating beam may carry a rack that drives a pinion through ninety degrees as the piston travels, and two opposed cylinders may be provided to give a reciprocatory movement, or a spring return may be provided.

Abstract: An electronic controller is provided to control the energization of an electrical actuator to readjust a valve which controls the flow of a fluid in a controllable process. The controller is responsive to two signals, one of which is produced by a process sensor to represent the instantaneous magnitude of a predetermined process parameter and the second of which constitutes a set signal representative of a desired magnitude of the parameter. The signals are compared, and the sense of any resulting error signal is used to control the direction of movement of the actuator while the instantaneous magnitude of the error signal, during a succession of equal time intervals, is used to control the rate of movement of the actuator by controlling the extent of movement of the actuator during each of the time intervals.

Abstract: An annular seat for use in a ball valve has two groups of pressure relief passageways each of which extends completely through the seat between its front and rear faces. The relief passageways in one group are located adjacent the outer periphery of the seat. The passageways in the second group are located radially inward of the passageways in the first group, and extend between the rear face of the seat and a curved sealing surface on the front face of the seat. A pair of such seats are disposed in a ball valve housing adjacent opposite sides of a rotatable ball. The interior seat support surfaces in the housing have machined recesses adjacent the central axial fluid passageway through each seat, to facilitate lip flexure of the seats. The overall arrangement provides a bidirectional valve which seals on the downstream side only of the valve, and which relieves excessive cavity pressure in the valve past the upstream seat.

Abstract: A pneumatic valve actuator having a rotatable output shaft is provided with a valve positioner comprising an axially displaceable spool valve and a pneumatic transducer responsive to applied signal air pressure for displacing the spool valve away from a neutral position to effect rotation of the actuator output shaft. The actuator output shaft is gear-connected to an element which rotates with the output shaft, and an elongated cantilever beam spring attached at one end to the rotatable element extends in a direction transverse to the axis of rotation of said element to the transducer for providing a feedback force which balances the control signal responsive transducer force when the actuator output shaft has rotated to a desired position.