Fluid flow control valve

Abstract

The invention provides a fluid flow control valve ( 1 ) comprising a cylindrical inlet chamber ( 2 ) having a fluid inlet aperture ( 3 ) and a coaxial waisted cylindrical outlet chamber ( 4 ) having a fluid outlet aperture ( 5 ), said inlet chamber containing a coaxial cylindrical cage ( 6 ) opening into said outlet chamber and said cage having in its cylinder wall at least one valve aperture ( 7 ) to allow fluid to pass from said fluid inlet aperture into said outlet chamber, said control valve further comprising a coaxial cylindrical plug ( 10 ) movable axially relative to said cage to close and open said valve aperture and a valve actuator ( 9, 11, 12, 13 ) operable to move said plug or cage relative to each other whereby to close or open said valve aperture, wherein said valve aperture is arranged to provide fluid exiting said cage from said inlet chamber with a velocity component tangential to the cylindrical axis ( 31 ) of said cage.

1 - 20 . (canceled) 
     
     
         21 . A fluid flow control valve comprising:
 an inlet chamber having a fluid inlet aperture;   a coaxial outlet chamber having a fluid outlet aperture;   a coaxial cage contained by said inlet chamber, said cage opening into said outlet chamber, said cage comprising a wall having a valve aperture to allow fluid to pass from said fluid inlet aperture into said outlet chamber;   wherein said outlet chamber is waisted such that in a flow direction from said cage to said fluid outlet aperture the outlet chamber decreases in cross-sectional area to a reduced internal diameter and increases in cross-sectional area from the reduced internal diameter to the fluid outlet aperture to define a waist of said outlet chamber; and   a coaxial plug movable axially relative to said cage to close and open said valve aperture and a valve actuator operable to move said plug or cage relative to each other to close or open said valve aperture;   wherein said valve aperture is arranged to provide fluid passing through said cage from said inlet chamber with a velocity component tangential to a central axis of said cage.   
     
     
         22 . A valve as claimed in  claim 21 , wherein the inlet aperture and/or inlet chamber are so formed that fluid flowing from said inlet aperture to said valve aperture is given a velocity component tangential to the central axis of said cage. 
     
     
         23 . A valve as claimed in  claim 21 , wherein said velocity component is both axially and tangentially oriented relative to the central axis of said cage such that said velocity component does not intersect the central axis and is not parallel to the central axis, and wherein said velocity component is oriented at an angle relative to a plane perpendicular to said central axis. 
     
     
         24 . A valve as claimed in  claim 21 , wherein a vortex breaker is positioned in said outlet chamber downstream of the waisted portion thereof. 
     
     
         25 . A valve as claimed in  claim 24 , wherein said vortex breaker comprises radially and axially extending vanes the fluid impact surfaces whereof are at a progressively decreasing angle relative to the axis of said outlet chamber from the end proximal to said cage to the end distal to said cage. 
     
     
         26 . A valve as claimed in  claim 21 , wherein said fluid inlet aperture and said fluid outlet aperture are substantially coaxial with said inlet and outlet chambers. 
     
     
         27 . A valve as claimed in  claim 21 , wherein said outlet chamber is substantially free from intrusive structural elements in the fluid flow path from said cage to the waist of said outlet chamber. 
     
     
         28 . A valve as claimed in  claim 21 , wherein an angle between a flow axis through said valve aperture in a plane perpendicular to the central axis of said cage and a radius from the axis of said cage to a center of said aperture is 35 to 88 degrees. 
     
     
         29 . A valve as claimed in  claim 21 , wherein an angle between a flow axis through said valve aperture and a plane perpendicular to the central axis of said cage at a center of said aperture is 5 to 70 degrees. 
     
     
         30 . A control valve comprising an inlet chamber comprising:
 a chamber sidewall having an inlet aperture therein, and an outlet aperture downstream of the inlet aperture; and   a coaxial cage contained by said inlet chamber and comprising a cage sidewall having therein a valve aperture oriented in a tangential direction with respect to a central axis of said cage, wherein the coaxial cage is open in a direction facing said outlet aperture;   wherein said plug is axially movable to permit or prevent fluid flow from said inlet aperture through said valve aperture and out through said outlet aperture.   
     
     
         31 . A valve comprising a plug and a cage, wherein the cage comprises a plurality of apertures oriented axially and tangentially relative to a central axis of said cage such that fluid passing through said apertures is provided with a velocity component that does not intersect the central axis and is not parallel to the central axis, and wherein said velocity component is oriented at an angle relative to a plane perpendicular to said central axis. 
     
     
         32 . A valve as claimed in  claim 31 , wherein an angle between a flow axis through said apertures in a plane perpendicular to the central axis of said cage and a radius from the central axis of said cage to a center of said apertures is 35 to 88 degrees. 
     
     
         33 . A valve as claimed in  claim 31 , wherein an angle between a flow axis through said apertures and a plane perpendicular to the central axis of said cage at a center of said apertures is 5 to 70 degrees.