摘要:
Un assemblage (17) d'une garniture de cage d'une vanne pour des vannes de commande d'anticavitation comprend une pluralité de manchons cylindriques emboîtés concentriquement (23, 25-29 et 41-46) avec des canaux annulaires d'étranglement d'écoulement de fluide (39, 47) définis entre des manchons adjacents. Chaque manchon possède un nombre identique de trous de plénum radiaux (38, 49) contenus dans le manchon et qui servent de chambre d'expansion, chaque trou de plénum intersectant au moins un canal d'étranglement d'écoulement pour obtenir des chemins d'écoulement de fluide tortueux de trous de plénum d'expansion et de canaux annulaires d'étranglement en alternance radialement au travers de l'assemblage de cage. La surface de section des canaux augmente d'un manchon à l'autre dans le sens d'écoulement du fluide pour obtenir une réduction étagée et progressive de la pression au fur et à mesure que l'écoulement avance au travers de l'assemblage de cage. La surface des trous de plénum est beaucoup plus grande que la surface de section totale de tous les canaux annulaires intersectant le trou de plénum de sorte que les canaux sont toujours des étranglements d'écoulement et les trous de plénum sont des chambres d'expansion.
摘要:
An integrated process control valve includes a fluid valve body having an inlet for receiving fluid, an outlet for discharging fluid, a fluid flow passage connecting the inlet and outlet, and a controllable throttling element which is moveable to selectively vary the flow rate of fluid through the fluid flow passage. The valve also includes an actuator coupled to the valve body and responsive to control signals for selectively moving the throttling element, a first pressure sensor disposed at the inlet of the valve body for producing a first signal representing the pressure of the fluid at the inlet, a second pressure sensor disposed at the outlet of the valve body for producing a second signal representing the pressure of the fluid at the outlet, a position sensor for producing a position signal indicating the position of the throttling element, and a utilization device for receiving the signals and either producing a display representing the signal values and/or producing control signals for supply to the actuator to cause the actuator to move the throttling element to thereby vary the fluid pressure at the inlet and outlet of the valve body. The control signals include pneumatic signals for developing pressures in the actuator to cause the actuator to move the throttling element. Sensors are provided for detecting the values of the pneumatic signals which may be displayed by the utilization device along with the display of representations of the other signal values, including the position signal values.
摘要:
A valve control system for positioning a valve in response to a command signal. The valve control system comprises a sensor for detecting the position of the valve and for generating an outer feedback signal, a valve location command circuit for comparing the command signal to the outer feedback signal to generate a correction signal, an actuator for positioning the valve in response to pneumatic pressure, a spool slidably disposed within a block to direct pneumatic pressure to the actuator, a spool positioning device for moving the spool to a desired position, a spool sensor for detecting the current position of the spool and generating an inner feedback signal, and a spool location command for comparing the correction signal to the inner feedback signal to generate a spool positioning signal to direct the spool positioning device to move the spool to the desired position.
摘要:
A valve control system for positioning a valve in response to a command signal. The valve control system comprises a sensor for detecting the position of the valve and for generating an outer feedback signal, a valve location command circuit for comparing the command signal to the outer feedback signal to generate a correction signal, an actuator for positioning the valve in response to pneumatic pressure, a spool slidably disposed within a block to direct pneumatic pressure to the actuator, a spool positioning device for moving the spool to a desired position, a spool sensor for detecting the current position of the spool and generating an inner feedback signal, and a spool location command for comparing the correction signal to the inner feedback signal to generate a spool positioning signal to direct the spool positioning device to move the spool to the desired position.
摘要:
A valve trim cage assembly (17) for anti-cavitation control valves compises a plurality of concentrically nested, cylindrical sleeves (23, 25-29 and 41-46) with fluid flow constricting annular channels (39, 47) defined between adjacent sleeves. Each sleeve has an identical multiplicity of radial plenum holes (38, 49) contained therein which serve as expansion chambers, each plenum hole intersecting at least one flow constricting channel to provide tortuous fluid flow paths of alternating expansion plenum holes and constricted annular channels radially through the cage assembly. The cross sectional area of the channels increase from sleeve to sleeve in the direction of fluid flow to provide staged and gradually decreasing pressure reduction as the flow proceeds through the cage assembly. The area of the plenum holes is much greater than the total cross sectional area of all annular channels intersecting the plenum hole such that the channels are always flow restricting and the plenums are expansion chambers.