Abstract:
A control valve has a body having an inlet and outlet, a valve seat between the inlet and outlet, a valve plug, and a cage adjacent the valve seat to provide guidance for the valve plug. The valve plug is movable between a closed position, where the valve plug sealingly engages the valve seat, and an open position, where the valve plug is spaced away from the valve seat. The cage has a circumferential wall having inner and outer surfaces and a plurality of passages formed through the wall. Each passage can have a first portion extending from the inner surface and a second portion extending from the outer surface, where the second portion has a diameter smaller than that of the first portion, can follow a non-linear path from the inner to outer surface, and/or can have a cross-sectional area that varies from the inner to outer surface.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    This disclosure relates generally to control valves and, more particularly, aerodynamic noise reducing cages for control valves. 
       BACKGROUND 
       [0002]    In typical control valves, a valve cage may provide guidance for a valve plug as the valve plug moves from a closed position in which the valve plug sealingly engages a valve seat to an open position in which the valve plug is disposed away from the valve seat. When the valve is in the open position, fluid flows from a valve inlet, passes through a passage between the valve seat and the valve plug, passes through the valve cage, and exits through a valve outlet. In addition to guiding the valve plug, a valve cage can also be used for additional functions, such as noise reduction. 
         [0003]    Referring to  FIG. 1 , a typical control valve  10  is shown. Control valve  10  generally includes a valve body  12  having an inlet  14  and an outlet  16  and a passageway  18  disposed between inlet  14  and outlet  16 . A valve seat  24  is disposed in passageway  18  between inlet  14  and outlet  16  and a solid cage  22  is disposed within valve body  12  adjacent valve seat  24 . A fluid control member, such as valve plug  26 , is positioned within body  12  and is disposed within cage  22 . Valve plug  26  interacts with the valve seat  24  to control fluid flow through the body  12 , such that valve plug  26  sealingly engages valve seat  24  in a closed position and is spaced away from valve seat  24  in an open position. A stem  28  is connected to valve plug  26  at one end and to an actuator  30  at another end. Actuator  30  controls movement of valve plug  26  within cage  22 . The cage  22  is positioned adjacent valve seat  24  and proximate valve plug  26  to provide guidance for valve plug  26 . 
         [0004]    In some gas applications, cage  22  has a plurality of passages  20  formed through a circumferential wall of cage  22 , which are used is to reduce the noise produced as the gas passes through cage  22 . Passages  20  are spaced specifically such that the jets of gas that are produced as the gas exits passages  20  do not converge and produce aerodynamic noise. Cages  22  used in these types of gas applications are typically used in a “flow up” orientation (e.g., the gas enters the center of cage  22  and passes from an inside surface to an outside surface of cage  22 ) and the spacing of passages  20  that is crucial to reduce the aerodynamic noise is on the outer surface of cage  22 . The spacing of passages  20  on the inner surface of cage  22  is also important, as this spacing is used to keep sufficient space between passages  20  to not allow flow to pass through more passages  20  than desired for accurate flow characteristics throughout the travel of valve plug  26 . 
         [0005]    For solid cages  22  used in gas applications where the process conditions produce aerodynamic noise as the medium flows through control valve  11 , drilled holes through the circumferential wall of cage  22  are typically used to form passages  20 . However, drilled hole cages are very cumbersome, time consuming, and costly to produce. Some drilled hole cages may contain thousands of holes and the only real feasible way to produce passages  20  was to drill them with a ⅛ inch drill bit. Acceptance criteria exists that allows a percentage of drill bits to break and be left in the cage and this process requires the use of special drilling machines that have a high degree of accuracy. 
         [0006]    In addition to the spacing of passages  20  on the outer surface of cage  22 , aerodynamic noise can also be reduced by providing a tortured, or non-linear, flow path for passages  20  or to varying the cross-sectional diameter of passages  20  as they pass through the wall of cage  22 . However, with a drilled holes through a solid cage  22 , creating passages  20  having a non-linear flow path or having a variable cross-sectional area is not possible. 
         [0007]    In addition to the noise issues that can be encountered in some gas applications, in some liquid applications, conditions can occur that will produce a condition where the liquid cavitates, which can cause severe damage to control valve  10 . In order to reduce the cavitation that can occur to the point that it does not damage control valve  10  or to direct it to an area that is less susceptible to cavitation damage, passages that decrease in diameter in the direction of fluid flow can be used. 
         [0008]    However, using drilled holes and conventional manufacturing techniques to create passages  20  in a solid cage  22  requires that the holes be step drilled from the outer surface of the cage, which limits these holes to having the larger diameter portion of passage  20  on the outer surface of cage  22  and the smaller diameter portion of passage  20  on the inner surface of cage  22 , since the larger diameter portion has to be drilled from the outside of cage  22 . This limits these types of cages  22  to applications using a “flow down” orientation (e.g., the fluid enters cage  22  from the outer surface and passes from the outside surface to the inside surface of cage  22 ) so that the pressure drops can be reduced as the flow goes through the control valve  10  and then downstream. The overriding reason this is done in this manner is the ability to drill the stepped holes from the outside of cage  22 . As described above, drilling the number of holes required through the wall of cage  22  for this type of application is very cumbersome, time consuming, and costly to produce. 
       BRIEF SUMMARY OF THE DISCLOSURE 
       [0009]    In accordance with one exemplary aspect of the present invention, a control valve comprises a body having an inlet and an outlet, a valve seat positioned in a passageway of the body between the inlet and the outlet, a valve plug positioned within the body, and a cage disposed within the body adjacent the valve seat and proximate the valve plug to provide guidance for the valve plug. The valve plug is movable between a closed position, in which the valve plug sealingly engages the valve seat, and an open position, in which the valve plug is spaced away from the valve seat. The cage comprises a circumferential wall having an inner surface and an outer surface and a plurality of passages formed through the wall and extending between the inner surface and the outer surface. Each of the passages comprises a first portion and a second portion, where the first portion of the passage extends from the inner surface of the wall and has a first diameter and the second portion of the passage extends from the outer surface of the wall and has a second diameter, smaller than the first diameter. 
         [0010]    In accordance with another exemplary aspect of the present invention, a control valve comprises a body having an inlet and an outlet, a valve seat positioned in a passageway of the body between the inlet and the outlet, a valve plug positioned within the body, and a cage disposed within the body adjacent the valve seat and proximate the valve plug to provide guidance for the valve plug. The valve plug is movable between a closed position, in which the valve plug sealingly engages the valve seat, and an open position, in which the valve plug is spaced away from the valve seat. The cage comprises a solid, unitary circumferential wall having an inner surface and an outer surface and a plurality of passages formed through the wall and extending between the inner surface and the outer surface. Each of the passages follows a non-linear path from the inner surface to the outer surface. 
         [0011]    In accordance with another exemplary aspect of the present invention, a control valve comprises a body having an inlet and an outlet, a valve seat positioned in a passageway of the body between the inlet and the outlet, a valve plug positioned within the body, and a cage disposed within the body adjacent the valve seat and proximate the valve plug to provide guidance for the valve plug. The valve plug is movable between a closed position, in which the valve plug sealingly engages the valve seat, and an open position, in which the valve plug is spaced away from the valve seat. The cage comprises a solid, unitary circumferential wall having an inner surface and an outer surface and a plurality of passages formed through the wall and extending between the inner surface and the outer surface. Each of the passages comprises a cross-sectional area that varies in size from the inner surface to the outer surface. 
         [0012]    In accordance with another exemplary aspect of the present invention, a cage for a control valve comprises a circumferential wall having an inner surface and an outer surface and a plurality of passages formed radially through the wall from the inner surface to the outer surface. Each of the passages comprises a first portion and a second portion, where the first portion of the passage extends from the inner surface of the wall and has a first diameter and the second portion of the passage extends from the outer surface of the wall and has a second diameter, smaller than the first diameter. 
         [0013]    In accordance with another exemplary aspect of the present invention, a cage for a control valve comprises a solid, unitary circumferential wall having an inner surface and an outer surface and a plurality of passages formed through the wall and extending between the inner surface and the outer surface. Each of the passages follows a non-linear path from the inner surface to the outer surface. 
         [0014]    In accordance with another exemplary aspect of the present invention, a cage for a control valve comprises a solid, unitary circumferential wall having an inner surface and an outer surface and a plurality of passages formed through the wall and extending between the inner surface and the outer surface. Each of the passages comprises a cross-sectional area that varies in size from the inner surface to the outer surface. 
         [0015]    In further accordance with any one or more of the foregoing exemplary aspects of the present invention, a control valve or cage for a control valve may further include, in any combination, any one or more of the following preferred forms. 
         [0016]    In one preferred form, the circumferential wall of the cage is solid. 
         [0017]    In another preferred form, each of the passages comprises a non-circular cross-sectional area. 
         [0018]    In another preferred form, the cross-sectional area is one of a square, a rectangle, a triangle, an oval, a stars, a polygon, and an irregular shape. 
         [0019]    In another preferred form, a sealed cavity is formed in the wall of the cage. 
         [0020]    In another preferred form, the non-linear path is one of an arcuate path, a helical path, and a stair-stepped shaped path. 
         [0021]    In another preferred form, each of the passages comprises a cross-sectional area that varies from the inner surface to the outer surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a cross-sectional view of an example control valve; 
           [0023]      FIG. 2A  is a cross-sectional view of an example cage that can be used with the control valve of  FIG. 1 ; 
           [0024]      FIG. 2B  is an enlarged portion of the indicated portion of  FIG. 2A ; 
           [0025]      FIG. 3A  is a side view of a second example cage that can be used with the control valve of  FIG. 1 ; 
           [0026]      FIG. 3B  is a perspective view of the example cage of  FIG. 3A  with a portion removed to expose the passages; 
           [0027]      FIG. 3C  is a top cross-sectional view of the cage of  FIG. 3A  taken along the line C-C in  FIG. 3A ; 
           [0028]      FIG. 3D  is a top cross-sectional view of the cage of  FIG. 3A  taken along the line D-D in  FIG. 3A ; 
           [0029]      FIG. 4A  is a side view of a third example cage that can be used with the control valve of  FIG. 1 ; 
           [0030]      FIG. 4B  is a top cross-sectional view of the cage of  FIG. 4A  taken along the line B-B in  FIG. 4A ; 
           [0031]      FIG. 4C  is a top cross-sectional view of the cage of  FIG. 4A  taken along the line C-C in  FIG. 4A ; 
           [0032]      FIG. 5A  is a side view of a fourth example cage that can be used with the control valve of  FIG. 1 ; 
           [0033]      FIG. 5B  is a top cross-sectional view of the cage of  FIG. 5A  taken along the line B-B in  FIG. 5A ; 
           [0034]      FIG. 5C  is a top cross-sectional view of the cage of  FIG. 5A  taken along the line C-C in  FIG. 5A ; 
           [0035]      FIG. 6A  is a side view of a fifth example cage that can be used with the control valve of  FIG. 1 ; 
           [0036]      FIG. 6B  is a top cross-sectional view of the cage of  FIG. 6A  taken along the line B-B in  FIG. 6A ; 
           [0037]      FIG. 6C  is a top cross-sectional view of the cage of  FIG. 6A  taken along the line C-C in  FIG. 6A ; 
           [0038]      FIG. 7A  is a side view of a sixth example cage that can be used with the control valve of  FIG. 1 ; 
           [0039]      FIG. 7B  is a top cross-sectional view of the cage of  FIG. 7A  taken along the line B-B in  FIG. 7A ; 
           [0040]      FIG. 7C  is a top cross-sectional view of the cage of  FIG. 7A  taken along the line C-C in  FIG. 7A ; 
           [0041]      FIG. 8A  is a side view of a seventh example cage that can be used with the control valve of  FIG. 1 ; 
           [0042]      FIG. 8B  is a perspective view of the example cage of  FIG. 8A  with a portion removed to expose the passages; 
           [0043]      FIG. 8C  is a top cross-sectional view of the cage of  FIG. 8A  taken along the line C-C in  FIG. 8A ; 
           [0044]      FIG. 8D  is a top cross-sectional view of the cage of  FIG. 8A  taken along the line D-D in  FIG. 8A ; 
           [0045]      FIG. 9A  is a side view of a eighth example cage that can be used with the control valve of  FIG. 1 ; 
           [0046]      FIG. 9B  is a top cross-sectional view of the cage of  FIG. 9A  taken along the line B-B in  FIG. 9A ; 
           [0047]      FIG. 9C  is a top cross-sectional view of the cage of  FIG. 9A  taken along the line C-C in  FIG. 9A ; 
           [0048]      FIG. 10  is a perspective view of a ninth example cage that can be used with the control valve of  FIG. 1 , with the passages shown in phantom; 
           [0049]      FIG. 11A  is a perspective view of an example cage that can be used with a control valve having side to side fluid flow, with a portion removed to expose the passages; and 
           [0050]      FIG. 11B  is a top cross-sectional view of the cage of  FIG. 11A  taken along the line B-B in  FIG. 11A . 
       
    
    
     DETAILED DESCRIPTION 
       [0051]    Referring to  FIGS. 2A-2B , one example of a cage  100  is shown that can be used with the control valve  10  described above and shown in  FIG. 1 . Cage  100  can be manufactured 0  using Additive Manufacturing Technology, such as direct metal laser sintering, full melt powder bed fusion, etc. Using an Additive Manufacturing Technology process, the 3-dimensional design of cage  100  is divided into multiple layers, for example layers approximately 20-50 microns thick. A powder bed, such as a powder based metal, is then laid down representing the first layer of the design and a laser or electron beam sinters together the design of the first layer. A second powder bed, representing the second layer of the design, is then laid down over the first sintered layer and the second layer is sintered together. This continues layer after layer to form the completed cage  100 . 
         [0052]    Using an Additive Manufacturing Technology process to manufacture cages for control valves allows the freedom to produce passages having various shapes and geometries, and other feature described below, that are not possible using current standard casting or drilling techniques. For example, as described above, cages used in liquid applications can be manufactured having passages that decrease in diameter in the direction of fluid flow to reduce cavitation in the control valve. However, using standard manufacturing techniques, these cages were limited to applications using a “flow down” orientation as the larger diameter portion of each passages could only be drilled/machined on the outer surface of the cage. However, as shown in  FIGS. 2A-2B , cage  100  can now be manufactured having passages that decrease in diameter from the inner surface to the outer surface, allowing cage  100  to be used in applications using a “flow up” orientation, which was not previously possible. 
         [0053]    As shown in  FIGS. 2A-2B , cage  100  generally includes a circumferential wall  102  forming a hollow central bore  112 , within which the valve plug  26  will slide to control fluid flow through cage  100 . Wall  102  defines a first end  104 , an opposing second end  106 , an inner surface  108 , and an opposing outer surface  110 . Passages  114  are formed through wall  102 , extend between inner surface  108  and outer surface  110 , and each have a first portion  116  and a second portion  118 . Passages  114  can be used to characterized fluid flowing through cage  100  by, for example, reducing the pressure of the fluid as it flows through passages  114 . First portion  116  of each passage  114  extends from inner surface  108  partially into wall  102  and has a first diameter D 1 , or cross-sectional area if passages  114  are not circular. Second portion  118  of each passage  114  extends from outer surface  110  partially into wall  102  and a second diameter D 2 , or cross-sectional area if passages  114  are not circular, that is smaller than diameter D 1  of first portion  116 . 
         [0054]    Having passages  114  decrease in diameter from inner surface  108  to outer surface  110 , which was not possible using standard manufacturing methods, means that cage  100  can now be used in liquid applications to reduce cavitation in control valves having a “flow up” orientation, which was not previously possible, and the design is not restricted from a manufacturing standpoint. This can be beneficial as some control valves perform better with increased capacity and control in the “flow up” orientation. In addition, having cages that can be in either “flow up” or “flow down” orientations allows piping flexibility to end users for any given application and provides more flexibility for more seal configurations, which can be flow direction dependent. 
         [0055]    As described above, passages  114  can have a generally circular cross-sectional area with a longitudinal axis that is perpendicular to the longitudinal axis of cage  100 . However, passages can also have other non-circular cross-sectional area, such as square, rectangle, triangle, oval, star, polygon, and irregular shapes. Furthermore, a sealed cavity  120 , such as a “lightning hole” or “weight saver” or manifold, can also be formed in wall  102  of cage  100 , to reduce the weight of cage  100  and save material, which was not possible using standard manufacturing techniques. Even with one or more of the above described features, such as passages  114  with decreasing diameter, passages  114  with non-circular cross sections, and/or sealed cavities  120  formed in wall  102  of cage  100 , using an Additive Manufacturing Technology, wall  102  can still be a solid, unitary structure. 
         [0056]    Referring to  FIGS. 3A-D , a second example of a cage  200  is shown that can be used with the control valve  10  described above and shown in  FIG. 1 . Cage  200  can also be manufactured using an Additive Manufacturing Technology process described in detail above for cage  100 . 
         [0057]    As shown in  FIGS. 3A-D , cage  200  generally includes a solid, unitary circumferential wall  202  forming a hollow central bore  212 , within which the valve plug  26  will slide to control fluid flow through cage  200 . Wall  202  defines a first end  204 , an opposing second end  206 , an inner surface  208 , and an opposing outer surface  210 . Passages  214  are formed through wall  202  and extend between inner surface  208  and outer surface  210 . Passages  214  can be used to characterized fluid flowing through cage  200  by, for example, reducing the pressure of the fluid as it flows through passages  214  or providing a tortured flow path through wall  202  to reduce the velocity of the fluid flowing through cage  200 . 
         [0058]    In the example shown in  FIGS. 3A-D , passages  214  are arcuate and follow a non-linear path from inner surface  208  to outer surface  210  of wall  202 . As can best be seen in  FIGS. 3C-D , passages  214  at vertically adjacent locations in cage  200  can curve in opposite directions, which provides a tortured flow path for the fluid passing through cage  200  and directs the exhaust from each vertically adjacent passages in different directions to avoid convergence of the exhaust paths and avoid producing aerodynamic noise. In the example shown, passages  214  formed in the first row of passages ( FIG. 3C ) curve from right to left and passages  214  formed in the second row of passages ( FIG. 3D ) curve from left to right. Rows of passages  214  will continue to alternate the direction of curvature so that each row of passages will exhaust in a direction different that the adjacent rows. 
         [0059]    As described above, passages  214  can have a generally circular cross-sectional area. However, passages  214  can also have other non-circular cross-sectional areas, such as square, rectangle, triangle, oval, star, polygon, and irregular shapes. In addition, the cross-sectional area of passages  214  can vary from inner surface  208  to outer surface  210 . For example, passages  214  can have a decreasing cross-sectional area from inner surface  208  to outer surface  210 , an increasing cross-section area from inner surface  208  to outer surface  210 , a cross-section area that fluctuates between increased and decreases size, or a cross-sectional area that changes shape as it passes from inner surface  208  to outer surface  210 . Furthermore, a sealed cavity  220 , such as a “lightning hole” or “weight saver” or manifold, can also be formed in wall  202  of cage  200 , to reduce the weight of cage  200  and save material, which was not possible using standard manufacturing techniques. 
         [0060]      FIGS. 4A-C  illustrate a third example of a cage  300  that can be used with the control valve  10  described above and shown in  FIG. 1 . Cage  300  can also be manufactured using an Additive Manufacturing Technology process described in detail above for cage  100 . Cage  300  is identical to cage  200  described above and uses the same reference numbers for identical parts, except that the rows of passages have the opposite curvature from those shown in cage  200 . For example, first row of arcuate, non-linear passages  314  ( FIG. 4B ) curve from left to right, the second row of passages ( FIG. 4C ) curve from right to left, and the rows of passages  314  continue to alternate. 
         [0061]    As described above, passages  314  can have a generally circular cross-sectional area. However, passages  314  can also have other non-circular cross-sectional areas, such as square, rectangle, triangle, oval, star, polygon, and irregular shapes. In addition, the cross-sectional area of passages  314  can vary from inner surface  208  to outer surface  210 . For example, passages  314  can have a decreasing cross-sectional area from inner surface  208  to outer surface  210 , an increasing cross-section area from inner surface  208  to outer surface  210 , a cross-section area that fluctuates between increased and decreases size, or a cross-sectional area that changes shape as it passes from inner surface  208  to outer surface  210 . 
         [0062]      FIGS. 5A-C  illustrate a fourth example of a cage  400  that can be used with the control valve  10  described above and shown in  FIG. 1 . Cage  400  can also be manufactured using an Additive Manufacturing Technology process described in detail above for cage  100 . Cage  400  is similar to cage  200  described above and uses the same reference numbers for identical parts. The main difference is that in each row, passages  414  alternate the direction of curvature from the horizontally adjacent passage  414 . In addition, each alternating vertical row of passages curves has curvature opposite that of the vertically adjacent rows. For example, each arcuate, non-linear passage  414  in the first row ( FIG. 5B ) has the opposite curvature from its two horizontally adjacent passages and each arcuate non-linear passage  414  in the second row ( FIG. 5C ) has the opposite curvature from its two horizontally adjacent passages and from passages  414  in vertically adjacent rows. 
         [0063]    As described above, passages  414  can have a generally circular cross-sectional area. However, passages  414  can also have other non-circular cross-sectional areas, such as square, rectangle, triangle, oval, star, polygon, and irregular shapes. In addition, the cross-sectional area of passages  414  can vary from inner surface  208  to outer surface  210 . For example, passages  414  can have a decreasing cross-sectional area from inner surface  208  to outer surface  210 , an increasing cross-section area from inner surface  208  to outer surface  210 , a cross-section area that fluctuates between increased and decreases size, or a cross-sectional area that changes shape as it passes from inner surface  208  to outer surface  210 . 
         [0064]      FIGS. 6A-C  and  7 A-C illustrate fifth and sixth examples of cages  500 ,  600  that can be used with the control valve  10  described above and shown in  FIG. 1 . Cages  500 ,  600  can also be manufactured using an Additive Manufacturing Technology process described in detail above for cage  100 . Cages  500 ,  600  are identical to cage  200  described above and use the same reference numbers for identical parts, except that passages  514 ,  614  have a more complicated curvature than passages  214  of cage  200 . For example, cage  500  ( FIGS. 6A-C ) has arcuate, non-linear passages  514  in the first row ( FIG. 6B ) that curve from right to left adjacent inner surface  208 , curve left to right in the middle of wall  202 , and curve right to left adjacent outer surface  210 . Conversely, arcuate, non-linear passages  514  in the second row ( FIG. 6C ) curve from left to right adjacent inner surface  208 , curve right to left in the middle of wall  202 , and curve left to right adjacent outer surface  210 . The arcuate, non-linear passages  614  of cage  600  ( FIGS. 7A-C ) have an S-shaped configuration. For example, passages  614  in the first row ( FIG. 7B ) curve from right to left adjacent inner surface  208 , curve left to right and back right to left in the middle of wall  202 , and curve left to right adjacent outer surface  210 . Conversely, passages  614  in the second row ( FIG. 7C ) curve from left to right adjacent inner surface  208 , curve right to left and back left to right in the middle of wall  202 , and curve right to left adjacent outer surface  210 . 
         [0065]    As described above, passages  514 ,  614  can have a generally circular cross-sectional area. However, passages  514 ,  614  can also have other non-circular cross-sectional areas, such as square, rectangle, triangle, oval, star, polygon, and irregular shapes. In addition, the cross-sectional area of passages  514 ,  614  can vary from inner surface  208  to outer surface  210 . For example, passages  514 ,  614  can have a decreasing cross-sectional area from inner surface  208  to outer surface  210 , an increasing cross-section area from inner surface  208  to outer surface  210 , a cross-section area that fluctuates between increased and decreases size, or a cross-sectional area that changes shape as it passes from inner surface  208  to outer surface  210 . 
         [0066]      FIGS. 8A-D  illustrate a seventh example of a cage  700  that can be used with the control valve  10  described above and shown in  FIG. 1 . Cage  700  can also be manufactured using an Additive Manufacturing Technology process described in detail above for cage  100 . Cage  700  is similar to cage  200  described above and uses the same reference numbers for identical parts. 
         [0067]    As shown in  FIGS. 8A-D , cage  700  generally includes a solid, unitary circumferential wall  202  forming a hollow central bore  212 , within which the valve plug  26  will slide to control fluid flow through cage  200 . Wall  202  defines a first end  204 , an opposing second end  206 , an inner surface  208 , and an opposing outer surface  210 . Passages  714  are formed through wall  202  and extend between inner surface  208  and outer surface  210 . Passages  714  can be used to characterized fluid flowing through cage  700  by, for example, reducing the pressure of the fluid as it flows through passages  714  or providing a tortured flow path through wall  202  to reduce the velocity of the fluid flowing through cage  700 . 
         [0068]    In the example shown in  FIGS. 8A-D , passages  714  follow a non-linear, generally stair-stepped shaped path from inner surface  208  to outer surface  210  of wall  202 , which provides a tortured flow path for the fluid passing through cage  700 . For example, as can be seen in  FIGS. 8C-D , passages  714  can extend radially from inner surface  208 , turn approximately 90 degrees and extend generally tangentially, turn approximately 90 degrees in the opposite direction to extend radially, turn approximately 90 degrees in the same direction to extend generally tangentially, and turn approximately 90 degrees in the opposite direction to extend radially to outer surface  210 . In addition, passages  714  in vertically adjacent rows can have stair-stepped shapes that turn in opposite directions. As can be seen in  FIG. 8C , passages  714  in the first row turn right, left, left, right, while passages  714  in the second row ( FIG. 8D ), vertically adjacent the first row, turn left, right, right, left. 
         [0069]    Furthermore, as can be seen in  FIGS. 8C-D , the locations of passages  714  at outer surface  210  can be angularly offset between vertically adjacent rows so that the exhaust from each vertically adjacent passage does not converge, which can be used to avoid producing aerodynamic noise. 
         [0070]    As described above and shown in  FIGS. 8A-D , passages  714  can have a generally square cross-sectional area. However, passages  714  can also have other cross-sectional areas, such as circular, rectangle, triangle, oval, star, polygon, and irregular shapes. In addition, the cross-sectional area of passages  714  can vary from inner surface  208  to outer surface  210 . For example, passages  714  can have a decreasing cross-sectional area from inner surface  208  to outer surface  210 , an increasing cross-section area from inner surface  208  to outer surface  210 , a cross-section area that fluctuates between increased and decreases size, or a cross-sectional area that changes shape as it passes from inner surface  208  to outer surface  210 . Furthermore, a sealed cavity  220 , such as a “lightning hole” or “weight saver” or manifold, can also be formed in wall  202  of cage  700 , to reduce the weight of cage  700  and save material, which was not possible using standard manufacturing techniques. 
         [0071]      FIGS. 9A-C  illustrate an eighth example of a cage  800  that can be used with the control valve  10  described above and shown in  FIG. 1 . Cage  800  can also be manufactured using an Additive Manufacturing Technology process described in detail above for cage  100 . Cage  800  is identical to cage  200  described above and uses the same reference numbers for identical parts, except for passages  814  formed through wall  202 . In cage  800 , passages  814  have a cross-sectional area that varies from inner surface  208  to outer surface  210 . In the example shown, the cross-sectional area of passages  814  increases from inner surface  208  to the center of wall  202  and decreases from the center of wall  202  to outer surface  210 . 
         [0072]    As described above, passages  814  can have a generally circular cross-sectional area. However, passages  814  can also have other non-circular cross-sectional areas, such as square, rectangle, triangle, oval, star, polygon, and irregular shapes. In addition, the cross-sectional area of passages  814  can vary from inner surface  208  to outer surface  210 . For example, passages  814  can have a decreasing cross-sectional area from inner surface  208  to outer surface  210 , an increasing cross-section area from inner surface  208  to outer surface  210 , a cross-section area that fluctuates between increased and decreases size, or a cross-sectional area that changes shape as it passes from inner surface  208  to outer surface  210 . 
         [0073]      FIG. 10  illustrates a ninth example of a cage  900  that can be used with the control valve  10  described above and shown in  FIG. 1 . Cage  900  can also be manufactured using an Additive Manufacturing Technology process described in detail above for cage  100 . Cage  900  is identical to cage  200  described above and uses the same reference numbers for identical parts, except that passages  914  through wall  202  have directional changes in the vertical direction as well as the horizontal direction. In the particular example shown, passages  914  are arcuate and follow a generally helical path through wall  202 . Furthermore, the locations of passages  914  at outer surface  210  can be angularly offset between vertically adjacent rows so that the exhaust from each vertically adjacent passage does not converge, which can be used to avoid producing aerodynamic noise. 
         [0074]    As described above and shown in  FIG. 10 , passages  914  can have a generally circular cross-sectional area. However, passages  914  can also have other non-circular cross-sectional areas, such as square, rectangle, triangle, oval, star, polygon, and irregular shapes. In addition, the cross-sectional area of passages  914  can vary from inner surface  208  to outer surface  210 . For example, passages  914  can have a decreasing cross-sectional area from inner surface  208  to outer surface  210 , an increasing cross-section area from inner surface  208  to outer surface  210 , a cross-section area that fluctuates between increased and decreases size, or a cross-sectional area that changes shape as it passes from inner surface  208  to outer surface  210 . 
         [0075]      FIGS. 11A-B  illustrate an example cage  1000  that can be used in control valves having side to side fluid flow, rather than “flow up” or “flow down” fluid flow as described above for control valve  10 . As shown in  FIG. 11B , in control valves using cage  1000 , the inlet flow F 1  will enter cage  1000  through one side, pass through circumferential wall  1002  into central bore  1012  and the outlet flow F 2  will exit central bore  1012  through the opposite side of cage  1000 . Cage  1000  can also be manufactured using an Additive Manufacturing Technology process described in detail above for cage  100 . 
         [0076]    Cage  1000  generally includes a solid, unitary circumferential wall  1002  forming a hollow central bore  1012 , within which the valve plug  26  will slide to control fluid flow through cage  1000 . Wall  1002  defines a first end  1004 , an opposing second end  1006 , an inner surface  1008 , and an opposing outer surface  1010 . Passages  1014  are formed through wall  1002  and extend between inner surface  1008  and outer surface  1010 . Passages  1014  can be used to characterized fluid flowing through cage  200  by, for example, reducing the pressure of the fluid as it flows through passages  1014  or providing a tortured flow path through wall  1002  to reduce the velocity of the fluid flowing through cage  1000 . 
         [0077]    In the example shown, passages  1014  have both straight portions and arcuate portions and follow a non-linear path from inner surface  1008  to outer surface  1010  of wall  1002  and direct the fluid through cage  1000 . In addition, the locations of passages  1014  at outer surface  1010  can be angularly offset between vertically adjacent rows and each row can be “reversed” from adjacent rows so that the exhaust from each vertically adjacent passage does not converge, which can be used to avoid producing aerodynamic noise. 
         [0078]    As described above, passages  1014  can have a generally circular cross-sectional area. However, passages  1014  can also have other non-circular cross-sectional areas, such as square, rectangle, triangle, oval, star, polygon, and irregular shapes. In addition, the cross-sectional area of passages  1014  can vary from inner surface  1008  to outer surface  1010 . For example, passages  1014  can have a decreasing cross-sectional area from inner surface  1008  to outer surface  1010 , an increasing cross-section area from inner surface  1008  to outer surface  1010 , a cross-section area that fluctuates between increased and decreases size, or a cross-sectional area that changes shape as it passes from inner surface  1008  to outer surface  1010 . Furthermore, a sealed cavity  1020 , such as a “lightning hole” or “weight saver” or manifold, can also be formed in wall  1002  of cage  1000 , to reduce the weight of cage  1000  and save material, which was not possible using standard manufacturing techniques. 
         [0079]    While various embodiments have been described above, this disclosure is not intended to be limited thereto. Variations can be made to the disclosed embodiments that are still within the scope of the appended claims.