Abstract:
Apparatus to increase the fluid flow in a valve are disclosed. An example apparatus includes a valve body having a fluid passageway, a valve cage located in the passageway and including a wall having an outer surface and an inner surface defining a cage bore with an axis. The wall has at least one flow zone comprising a plurality of through openings, each through opening extending between the inner and outer surfaces to define an opening axis extending through the wall. The opening axis is disposed at a non-orthogonal angle with respect to a reference plane disposed orthogonal to the axis of the cage bore. A valve plug is axially slidable in the cage bore.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    This disclosure relates generally to apparatus to increase fluid flow in a valve and, more particularly, to apparatus to increase the fluid flow in a fluid passageway through a valve cage of a fluid control valve. 
       BACKGROUND 
       [0002]    Processing plants use control valves in a wide variety of applications such as, for example, controlling product flow in a food processing plant, maintaining fluid levels in large tank farms, etc. Automated control valves are used to manage the product flow or to maintain the fluid levels by functioning like a variable passage. The amount of fluid flowing through a valve body of the control valve can be accurately controlled by precise movement of a valve control member (e.g., a plug). The fluid flow capacity of the control valve can be increased by enlarging the size of the control valve. However, this typically increases the cost of the control valve. 
       SUMMARY 
       [0003]    An apparatus to increase fluid flow in a valve comprises a valve body having a fluid passageway, a valve cage located in the passageway, and a valve plug axially slidable in the cage bore. The valve cage includes a wall having an inner surface and an outer surface, the inner surface defining a cage bore having an axis. The wall has at least one flow zone comprising a plurality of through openings each extending between the inner and outer surfaces to define an opening axis extending through the wall. Each opening axis is disposed at a non-orthogonal angle with respect to a reference plane disposed orthogonal to the axis of the cage bore, and each opening is spaced-apart from an adjacent opening. 
         [0004]    Additionally, an apparatus to increase fluid flow in a valve includes a valve body having a fluid passageway, a valve cage located in the passageway, and a valve plug axially slidable in the cage bore. The valve cage comprises a wall having an inner surface and an outer surface, the inner surface defining a cage bore having an axis, and the wall having at least one flow zone comprising a plurality of through openings each having a curved axis extending between the inner and outer surfaces. Each through opening is spaced-apart from an adjacent opening. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a partially cut-away schematic illustration of a known valve assembly. 
           [0006]      FIG. 2  is an enlarged illustration of the valve cage of the known valve assembly of  FIG. 1 . 
           [0007]      FIG. 3  is partially cut-away schematic illustration of an example valve assembly. 
           [0008]      FIG. 4  is partially cut-away schematic illustration of an example valve assembly. 
           [0009]      FIG. 5  is an enlarged illustration of a portion of another example valve assembly. 
           [0010]      FIG. 6  is an enlarged illustration of a portion of yet another example valve assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    In general, the example apparatus to increase fluid flow in a valve described herein may be utilized for fluid flow in various types of assemblies or devices. Additionally, while the examples disclosed herein are described in connection with the control of product flow for the processing industry, the examples described herein may be more generally applicable to a variety of control operations for different purposes. 
         [0012]      FIG. 1  is a partially cut-away schematic illustration of a known control valve assembly  10 . The control valve assembly  10  includes a valve body  11  having an inlet port  12  and an outlet port  14 , a valve cage  16 , a valve plug assembly  18  and a bonnet assembly  20 . In other control valve assemblies, the inlet and the outlet may be reversed whereby fluid flows in an opposite direction. The valve cage  16  has a cylindrical wall  22  defining a bore  24  located along an axis A. The valve cage  16  defines a valve seat  26  having one or more fluid flow zones  28 , which enable fluid flow between an exterior wall surface  32  and an interior wall surface  34  of the cylindrical wall  22 . The valve plug assembly  18  includes a generally cylindrical-shaped valve plug  40  slidably disposed within the bore  24  and attached to a stem  42 . As shown clearly in  FIG. 1 , fluid flow through the valve body  11  is determined by the position of the valve plug assembly  18  in the valve cage  16 . For purposes of illustrations, the left half of the valve plug assembly  18  is depicted in a closed fluid flow position and the right half of the valve plug assembly  18  is depicted in an open fluid flow position. 
         [0013]    Referring to  FIGS. 1 and 2 , each fluid flow zone  28  includes a plurality of spaced-apart slots  29  extending between the exterior wall surface  32  and the interior wall surface  34  of the valve cage  16 . Each slot  29  is generally rectangular in shape and has a longitudinal axis  50  extending circumferentially relative to the valve cage  16  and oriented at an angle C relative to a reference plane B extending orthogonally relative to the axis A. Each slot  29  also has an opening or slot axis S extending radially relative to the axis A. The slots  29  extend straight through the cylindrical wall  22  of the valve cage  16  such that each slot axis S lies either in or parallel to the reference plane B. 
         [0014]    The slots  29  present fluid flow passages requiring abrupt changes of direction of the fluid flowing from the inlet  12  to the outlet  14  via the slots  29  (see  FIG. 1 ). The fluid must change direction as it flows through the slots  29  to the outlet port  14 . The change of direction of fluid flow results from the fluid being directed by the slots  29  straight through the wall  22  from the interior wall surface  34  to the exterior wall surface  36 . In other words, the fluid flow through each slot  29  is in a direction lying either in or parallel to the reference plane B. Typically, a change in the direction of fluid flow is accompanied losses of fluid flow velocity, fluid pressure, and the volume of fluid flow. An increase in the fluid flow capacity of the control valve assembly  10  can be accomplished by enlarging the size of the control valve assembly  10 . However, this increases the cost of the control valve assembly  10 . 
         [0015]    Example apparatus to increase the fluid flow in a valve are illustrated in  FIGS. 3-6 . Structural elements which are similar to elements in  FIGS. 1 and 2  are indicated in  FIGS. 3-6  by reference numerals increased by 100, 200, 300 or 400, respectively. 
         [0016]      FIG. 3  is a partially cut-away schematic illustration of an example control valve assembly  100 . The example control valve assembly  100  includes a valve body  106  having an inlet port  112  and an outlet port  114 , a valve cage  116 , a valve plug assembly  118  and a bonnet assembly  120 . The valve cage  116  is a sleeve-like structure having a cylindrical wall  122  defining a bore  124  located along an axis Y. The valve cage  116  defines a valve seat  126  having one or more fluid flow zones  130 , which enable fluid flow between an outer surface  132  and an inner surface  134  of the cylindrical wall  122 . The valve plug assembly  118  includes a generally cylindrical-shaped valve plug  140  slidably disposed within the bore  124  and attached to a stem  142 . 
         [0017]    Each fluid flow zone  130  includes a plurality of spaced-apart through openings  136  extending between the outer surface  132  and the inner surface  134 . Preferably, the through openings  136  in each fluid flow zone  130  are spaced-apart from and parallel to one another. The through openings  136  may be disposed in any type of pattern in the cylindrical wall  122 . Each through opening  136  is generally annular in shape, but may have other shapes such as, for example, rectangular, oblong, oval, parallel-piped, diamond-shaped, etc. As depicted in  FIG. 3 , a reference plane X extends orthogonally relative to the axis Y. Each through opening  136  defines an opening axis R extending through the wall  122 . The opening axis R is disposed at a non-orthogonal angle such as, for example, a non-orthogonal angle D illustrated in  FIG. 3 , relative to the reference plane X. In  FIG. 3 , the illustrated non-orthogonal angle D is 45°. However, other angles greater than 0° may be utilized for positioning the through openings  136  in the wall  122 . The direction of fluid flow between the inlet port  112  and the outlet port  114  determines the desired angle of the opening axis R relative to the reference plane X. 
         [0018]    The extent that the non-orthogonal angle D varies from the reference plane X may determine how many through openings  136  can be located in the valve cage  116 . Thus, the non-orthogonal angle D is preferably, but not necessarily, in the range of 5-85°. The non-orthogonal angle D also determines the quantity of fluid that may flow through each through opening  136 . By disposing the opening axis R of the through opening  136  at the non-orthogonal angle D relative to the reference plane X, the opening axis R is oriented along the direction of fluid flow from the inlet port  112  to the outlet port  114 . Such an orientation produces a more efficient and/or less turbulent fluid flow through the through openings  136 , as compared to the fluid flow through slots having a longitudinal axis either in or parallel to a reference plane orthogonal to the bore axis (e.g., see  FIG. 2  where each opening  29  has a longitudinal axis S that is either in or parallel to the reference plane B). The more efficient and/or less turbulent fluid flow through the through openings  136  results in an increase in fluid flow capacity of the example valve assembly  100  without requiring an increase the overall size and cost of the example valve assembly  100 . 
         [0019]      FIG. 4  is a partially cut-away schematic illustration of an example control valve assembly  200 . The example control valve assembly  200  includes a valve body  206  having an inlet port  212  and an outlet port  214 , a valve cage  216 , a valve plug assembly  218  and a bonnet assembly  220 . The valve cage  216  is a sleeve-like structure having a cylindrical wall  222  defining a bore  224  located along an axis Y. The valve cage  216  defines a valve seat  226  having one or more fluid flow zones  230 , which enable fluid flow between an outer surface  232  and an inner surface  234  of the cylindrical wall  222 . The valve plug assembly  218  includes a generally cylindrical-shaped valve plug  240  slidably disposed within the bore  224  and attached to a stem  242 . 
         [0020]    Each fluid flow zone  230  includes a plurality of spaced-apart through openings  236  extending between the outer surface  232  and the inner surface  234 . Preferably, the through openings  236  in each fluid flow zone  230  are spaced-apart from and parallel to one another. The through openings  236  may be disposed in any type of pattern in the cylindrical wall  222 . Each through opening  236  is generally rectangular in shape, but may have other slot-like shapes such as, for example, oblong, oval, parallel-piped, diamond-shaped, etc. As depicted in  FIG. 4 , a reference plane X extends orthogonally relative to the axis Y. Each through opening  236  defines an opening axis T extending through the wall  222 . The opening axis T is disposed at a non-orthogonal angle such as, for example, a non-orthogonal angle E illustrated in  FIG. 4 , relative to the reference plane X. In  FIG. 4 , the illustrated non-orthogonal angle E is 45°. However, other angles greater than 0° may be utilized for positioning the through openings  236  in the wall  222 . The direction of fluid flow between the inlet port  212  and the outlet port  214  determines the desired angle of the opening axis T relative to the reference plane X. 
         [0021]    The extent that the non-orthogonal angle E varies from the reference plane X may determine how many through openings  236  can be located in the valve cage  216 . Thus, the non-orthogonal angle E is preferably, but not necessarily, in the range of 5-85°. The non-orthogonal angle E also determines the quantity of fluid that may flow through each through opening  236 . By disposing the opening axis T of the through opening  236  at the non-orthogonal angle E relative to the reference plane X, the opening axis T is oriented along the direction of fluid flow from the inlet port  212  to the outlet port  214 . As previously described herein, such an orientation produces a more efficient and/or less turbulent fluid flow through the through openings  236 , as compared to the fluid flow through slots having a longitudinal axis either in or parallel to a reference plane orthogonal to the bore axis (e.g., see  FIG. 2  where each opening  29  has a longitudinal axis S that is either in or parallel to the reference plane B). The more efficient and/or less turbulent fluid flow through the through openings  236  results in an increase in fluid flow capacity of the example valve assembly  200  without requiring an increase the overall size and cost of the example valve assembly  200 . 
         [0022]      FIG. 5  is an enlarged illustration of a portion of another example valve assembly  300 . A generally cylindrical-shaped valve plug  340  is slidably disposed within a bore  324  (about the axis Y) of a valve cage  316 . The valve cage  316  includes a cylindrical wall  322  having an outer surface  332  and an inner surface  334 . A flow zone  330  includes through openings  336  that extend between the outer surface  332  and the inner surface  334  to enable fluid flow through the openings  336  as the valve plug  340  is moved relative to the valve cage  316 . The through openings  336  in the fluid flow zone  330  are spaced-apart from and parallel to one another. However, the through openings  336  may be disposed in any type of pattern in the cylindrical wall  322 . 
         [0023]    Each through opening  336  is generally annular in shape, but may have other shapes such as, for example, rectangular, oblong, oval, parallel-piped, diamond-shaped, etc. As depicted in  FIG. 5 , the reference plane X extends orthogonally relative to the axis Y. Each through opening  336  defines an opening axis U extending through the wall  322 . The opening axis U is disposed at a non-orthogonal angle such as, for example, a non-orthogonal angle F illustrated in  FIG. 5 , relative to the reference plane X. In  FIG. 5 , the illustrated non-orthogonal angle F is 45°. However, other angles greater than 0° may be utilized for positioning the through openings  336  in the wall  322 . Similar to the range disclosed for the non-orthogonal angle E in  FIG. 4 , the non-orthogonal angle F in  FIG. 5  is preferably, but not necessarily, in the range of 5-85°. 
         [0024]    The through openings  336  each include an enlarged or chamfered area  338  at the outer surface  332 . In some circumstances, a sharp corner or edge at the interface of a through opening  336  with the outer surface  332  may result in turbulence in the fluid flow and a corresponding decrease in fluid flow capacity. The presence of the enlarged or chamfered areas  338  at the interfaces of the through openings  336  with the outer surface  332  minimizes the possibility of turbulent fluid flow and provides a relatively smooth fluid flow through the through openings  336 . The smooth fluid flow through the through openings  336  results in an increase in fluid flow capacity of the example valve assembly  300  without requiring an increase the overall size and cost of the valve example valve assembly  300 . 
         [0025]      FIG. 6  is an enlarged illustration of a portion of yet another example valve assembly  400 . A generally cylindrical-shaped valve plug  440  is slidably disposed within a bore  424  (about the axis Y) of a valve cage  416 . The valve cage  416  includes a cylindrical wall  422  having an outer surface  432  and an inner surface  434 . A flow zone  430  includes curved through openings  437  that extend between the outer surface  432  and the inner surface  434  to enable fluid flow through the curved through openings  437  as the valve plug  440  is displaced relative to the to the valve cage  416 . The curved through openings  437  in the fluid flow zone  430  are spaced-apart from and parallel to one another. However, the curved through openings  437  may be disposed in any type of pattern in the cylindrical wall  422 . 
         [0026]    Each curved through opening  437  is generally annular in shape, but may have other shapes such as, for example, rectangular, oblong, oval, circular, parallel-piped, diamond-shaped, etc. As depicted in  FIG. 6 , the reference plane X extends orthogonally relative to the axis Y. Each curved through opening  437  defines an opening axis V extending through the wall  422 . The opening axis V is curved or nonplanar relative to the reference plane X. The curved through openings  437  each provide a smooth transition for fluid flow between the outer surface  432  and the inner surface  434  and, by directing the fluid flow through a curved through opening  437 , the valve cage  416  may provide an enhanced fluid flow capacity. 
         [0027]    The curved through openings  437  also each include an enlarged or chamfered area  438  at the outer surface  432 . As similarly described in connection with  FIG. 5 , the presence of the enlarged or chamfered areas  438  at the interfaces of the curved through openings  437  with the outer surface  432  minimizes the possibility of turbulent fluid flow and provides a relatively smooth (i.e., relatively low turbulence) fluid flow through the curved through openings  437 . The smooth fluid flow through the curved through openings  437  results in an increase in fluid flow capacity of the example valve assembly  400  without requiring an increase the overall size and cost of the valve example valve assembly  400 . 
         [0028]    Although certain example apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.