Patent Publication Number: US-2016238149-A1

Title: Fluid valve apparatus having enclosed seals

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent arises from a continuation of U.S. patent application Ser. No. 13/953,411, filed on Jul. 29, 2013, titled Fluid Valve Apparatus having Enclosed Seals, which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates generally to valves and, more particularly, to fluid valve apparatus having enclosed seals. 
     BACKGROUND 
     Control valves (e.g., sliding stem valves, rotary valves, axial flow valves, globe valves, etc.) are commonly used in industrial processes (e.g., oil and gas pipeline distribution systems and chemical processing plants) to control the flow of process fluids. To control fluid flow, a control valve often employs a flow control member (e.g., a plate, a disk, a plug, etc.) that moves relative to a valve seat positioned in a valve body of the control valve. For example, a control valve having a relatively tight shut-off capability provides shut-off control such that substantially no fluid flows through the control valve when the flow control member sealingly engages the valve seat. Fluid flow may be allowed and/or increased as the flow control member moves and/or rotates away from the valve seat. 
     Some known control valves employ a seal as part of the valve seat and/or the control flow member (e.g., along a peripheral edge of the flow control member) to effect and/or improve a seal between the flow control member and the valve seat. Typically, industrial process conditions, such as pressure conditions, operation temperatures, and the type of process fluids dictate the type of seals that may be used. For example, soft seals composed of elastomers (e.g., EPDM) or fluoropolymers (e.g., PTFE) allow the flow control member to engage the valve seat more tightly and, thus, provide improved sealing characteristics to help prevent or restrict fluid flow through the control valve (i.e., provide relatively tight shut-off or seal characteristics). However, soft seals composed of elastomers or fluoropolymers have lower temperature and/or erosion resistance characteristics compared to, for example, seals composed of metal. For example, some soft seals may become damaged when used with process fluids having temperatures greater than 600° F. and/or may erode when used with process fluids having significant fluid pressures or velocities. Thus, such known seals can be used in a limited temperature range and/or with flows having a limited pressure or velocity range. 
     Seals composed of metal, on the other hand, provide greater resistance to temperature and erosion compared to soft seals. While such known metal seals have greater resistance to high temperatures and erosion, such known metal seals provide inferior sealing capabilities compared to soft seals and, thus, metal seals may not meet desired shut-off capability and/or classification. In some applications, control valves employ a laminated seal composed of graphite and stainless steel. Although such known laminated graphite seals enable a relatively tight shut-off over a wide temperature range, portions of the graphite layers that remain exposed to the process fluids having relatively high pressures or velocities may be susceptible to erosion. 
     SUMMARY 
     An example includes a seal having an inner core composed of a first material and an outer sheath composed of a second material different than the first material, a carrier having a first portion and a second portion extending from the first portion. The first portion couples to the seal. The second portion clamps between a retainer and a valve body of a fluid valve to couple the seal to the valve body. A first surface of the second portion engages the retainer and a second surface of the second portion opposite the first surface engages the valve body when the second portion of the carrier is clamped between the retainer and the valve body. 
     Another example apparatus includes a valve body defining a fluid flow passageway between an inlet and an outlet. A flow control member is positioned in the fluid flow passageway to control fluid flow between the inlet and the outlet. A retainer is removably coupled to the valve body. A seal assembly is positioned between the retainer and the flow control member. The flow control member is to engage the seal assembly to restrict or prevent fluid flow through the fluid flow passageway. The seal assembly includes a seal and a carrier coupled to the seal. The carrier is to enable the seal to compress or deflect when the flow control member engages the seal. The carrier is to urge the seal radially inward toward a center of the fluid flow passageway and toward a sealing edge of the flow control member to provide a sufficiently tight seal between the seal and the sealing edge of the flow control member. The carrier has a first end and a second end. The first end is coupled to the seal and the second end is clamped between the retainer and the valve body. 
     Another example apparatus includes a flow control member positioned between an inlet and an outlet of a fluid flow passageway of a fluid valve. A retainer is removably coupled to a valve body of the fluid valve. A seal assembly is positioned within the fluid flow passageway. The seal assembly includes a seal having an annular ring composed of a first material and an outer sheath composed of a second material different than the first material, and a carrier coupled to the seal. The carrier having a first portion to support the seal and a second portion to be clamped between the retainer and the valve body to suspend the seal in the fluid flow passageway adjacent a sealing surface of the flow control member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a fluid valve constructed in accordance with the teachings disclosed herein. 
         FIG. 2  is a partial cross-sectional view of the example fluid valve shown in  FIG. 1 . 
         FIG. 3  is an enlarged view of the example fluid valve shown in  FIG. 2 . 
         FIG. 4  is a partial cross-sectional view of another example fluid valve constructed in accordance with the teachings disclosed herein. 
         FIG. 5  is a partial cross-sectional view of the example fluid valve of  FIG. 4 . 
         FIG. 6  is a partial cross-sectional view of another example fluid valve constructed in accordance with the teachings disclosed herein. 
         FIG. 7  is a partial cross-sectional, enlarged view of the example fluid valve of  FIG. 6 , but implemented with another example seal disclosed herein. 
         FIG. 8  illustrates another example fluid valve constructed in accordance with the teachings disclosed herein. 
         FIG. 9  is a partial cross-sectional view of the example fluid valve of  FIG. 8  shown in a closed position. 
         FIG. 10  is a partial, enlarged view of the fluid valve of  FIGS. 8 and 9 . 
         FIG. 11  illustrates another fluid valve constructed in accordance with the teachings disclosed herein. 
         FIGS. 12A and 12B  illustrate another fluid valve constructed in accordance with the teachings disclosed herein. 
     
    
    
     Certain examples are shown above in the identified figures and described below in detail. In describing these examples, like or identical reference numbers are used to identify the same or similar elements. The figures are not necessarily to scale. Certain features and views of the figures may be exaggerated in scale or may be in schematic form for clarity or conciseness. Additionally, several examples have been described throughout this specification. Any features from any example may replace, be included with, or otherwise combine with other features from other examples. 
     DETAILED DESCRIPTION 
     The example fluid valves disclosed herein employ movable flow control members having a sealing surface to sealingly engage a valve seat of the fluid valve. More specifically, the example flow control member may include a retainer removably coupled to a body to define a sealing cavity of the flow control member. A seal or seal assembly is positioned within the sealing cavity and may be clamped between the body of the flow control member and the retainer to define the sealing surface of the flow control member. In some examples, the example flow control members disclosed herein may employ a locking or breakout prevention feature, which prevents the seal or seal assembly from loosening or becoming dislodged from the sealing cavity when the flow control member moves to an open position under a relatively high pressure fluid flow. In some examples, the locking feature may be provided by a clamping plate or surface of the seal or seal assembly that is captured or pinched between a wall or surface of the retainer and a wall or surface of the body to provide an increased holding force when the retainer is coupled to the body. In some examples, the seal or seal assembly may include one or more shoulders that are positioned in channels or grooves formed in the retainer and/or the body of the flow control member to retain the seal or the seal assembly within a sealing cavity of the flow control member. 
     The example seal or seal assembly disclosed herein may include a first seal portion (e.g., a graphite seal) encased or wrapped (e.g., fully or partially) with a second seal portion (e.g., a protective sheath, film or strip of material). The second seal portion is a relatively thin layer of material compared to the first seal portion and protects the first seal portion from damage that may otherwise occur when the first seal portion is exposed to process fluids having relatively high temperatures and/or pressures or velocities. 
     The example second seal portion disclosed herein may be composed of metal or any other material that provides greater resistance to high temperatures and/or erosion than provided by the first seal portion. Additionally, while the second seal portion provides protection to the first seal portion, the second seal portion is relatively thin compared to the first seal portion so that the second seal portion can conform, bend, flex and/or otherwise seal against a sealing surface of a fluid device. As a result, the relatively thin second seal portion enables the first seal portion to resiliently deform to cause the second seal portion to seal against a sealing surface of a fluid valve to provide a shut-off that is substantially equivalent to a shut-off capability typically provided by the first seal portion. Thus, although the second seal portion surrounds a sealing surface of the first seal portion, the second seal portion does not degrade or affect the sealing capabilities of the first seal portion. In other words, even though the second seal portion is positioned between the first seal portion and the seating surface of the fluid valve, the seal assembly provides a sealing capability of the first seal portion. Thus, the example seal assembly disclosed herein may provide greater temperature and/or erosion resistance while providing a relatively tight shut-off capability (e.g., a shut-off capability otherwise provided by a first seal portion composed of expanded graphite material). 
     An example seal that may be incorporated with the example fluid valves disclosed herein is described in U.S. Pat. No. 4,457,491, which is incorporated herein by reference in its entirety. 
       FIG. 1  depicts a fluid or rotary valve  100  constructed in accordance with the teachings disclosed herein. The rotary valve  100  shown in  FIG. 1  may, for example, be used to control process fluids, such as natural gas, oil, water, etc. over a wide range of temperatures and/or fluid pressures. As shown in  FIG. 1 , the rotary valve  100  defines a fluid flow passageway  102  between an inlet  104  and an outlet  106  and a movable flow control member  108  (e.g., a disk) is interposed in the fluid flow passageway  102  to control fluid flow through the fluid flow passageway  102 . More specifically, the flow control member  108  is operatively coupled to an actuator (not shown) (e.g., a manual actuator, a pneumatic actuator, etc.) via a valve shaft  110  that causes the flow control member  108  to move (e.g., rotate, turn, etc.) relative to a seating surface  114  (e.g., a seat ring) of the fluid flow passageway  102  between an open position and a closed position. 
     When the flow control member  108  is in the closed position, a sealing surface  116  of the flow control member  108  engages the seating surface  114  (e.g., a seat ring) of the rotary valve  100  to prevent or restrict fluid flow through the fluid flow passageway  102 . The sealing surface  116  of the illustrated example is defined by a seal or seal assembly  118 . The flow control member  108  of the illustrated example includes a retainer  120  removably coupled to a body  124  of the flow control member  108  via a plurality of fasteners  122  to retain or clamp the seal  118  to the body  124 . 
       FIG. 2  is a cross-sectional view of a portion of the example rotary valve  100  of  FIG. 1  showing the flow control member  108  in a closed position  200 . The flow control member  108  of the illustrated example comprises a butterfly valve disk  202 . When the retainer  120  is coupled to the body  124 , the retainer  120  and the body  124  define a sealing cavity  204 . The sealing cavity  204  of the illustrated example is defined adjacent an outer peripheral edge  206  of the body  124  and/or the retainer  120 . More specifically, the sealing cavity  204  defines an annular groove or slot  208  between the retainer  120  and the body  124 . As shown in this example, the annular groove  208  is formed or provided on an inner surface  210  of the retainer  120 . Additionally or alternatively, in other examples, the annular groove  208  may be positioned on the body  124  of the disk  202 . 
     The seal  118  of the illustrated example is positioned, clamped or otherwise retained within the sealing cavity  204  via the retainer  120 . The seal  118  of the illustrated example is an annular ring that at least partially protrudes from the sealing cavity  204  relative to the peripheral edge  206  of the flow control member  108  to sealingly engage the seating surface  114  of the rotary valve  100 . 
       FIG. 3  is an enlarged view of a portion of the rotary valve  100  shown in  FIGS. 1 and 2 . The seal  118  of the illustrated example includes a first seal portion  302  composed of a first material and a second seal portion  304  composed of a second material different than the first material. The first seal portion  302  is an inner core or layer composed of the first material and the second seal portion  304  is an outer layer composed of the second material. More specifically, the first seal portion  302  of the illustrated example is substantially encased or enclosed by the second seal portion  304 . In other words, the second seal portion  304  substantially surrounds a perimeter of the first seal portion  302  such that a gap  306  between ends  308 ,  310  of the second seal portion  304  is provided to expose a portion of the first seal portion  302 . In this manner, the gap  306  of the illustrated example allows the first seal portion  302  to expand, for example, when the flow control member  108  is in the closed position  200  and the seal  118  is sealingly engaged with the seating surface  114 . In other examples, the second seal portion  304  may enclose or encase (e.g., completely enclosed) the first seal portion  302  such that the ends  308 ,  310  of the second seal portion  304  engage or overlap one another such that no portion of the first seal portion  302  is exposed. 
     The first seal portion  302  of the illustrated example is a core  312  composed of graphite or expanded graphite material having flexible, resilient characteristics. The second seal portion  304  is a thin metal sheet, strip, cover or sheath  314  that conforms to a profile of the core  312 . The sheath  314  of the illustrated example is composed of a metallic material and is relatively thin compared to the core  312 . The second seal portion of the illustrated example may be composed of stainless steel, an alloy, and/or any other material (e.g., a non-metallic or plastic material) that may be used to improve temperature and erosion resistance of the first seal portion. In particular, the sheath  314  has a thickness that is significantly thinner than a thickness of the core  312  such that the core  312  causes the sheath  314  to conform to seating surface  114  of the rotary valve  100  when the flow control member  108  sealingly engages the seating surface  114 . In the illustrated example, the core  312  comprises a curved surface  316  having a radius to conform to a radius of the seating surface  114  of the rotary valve  100 . When the seal  118  is in sealing engagement with the seating surface  114 , the second seal portion  304  or sheath  314  transfers a load between the seating surface  114  and the first seal portion  302 . In operation, the sheath  314  protects the core  312  from damage and/or erosion when the seal  118  is exposed to process fluids having relatively high temperatures and/or pressures or velocities that would otherwise damage and/or erode the core  312  absent the sheath  314 . 
       FIG. 4  illustrates another example rotary valve  400  disclosed herein.  FIG. 5  is an enlarged view of a portion of the example rotary valve  400  of  FIG. 4 . The example rotary valve  400  is substantially similar to the rotary valve  100  of  FIGS. 1-4 , but is implemented with another example seal  402  disclosed herein. 
     The example rotary valve  400  includes a flow control member  404  having a retainer  406  coupled to a body  408  to define a sealing cavity  410  about a peripheral edge  412  of the retainer  406  and/or the body  408 . The seal  402  of the illustrated example is positioned or clamped within the sealing cavity  410 . The seal  402  includes a first seal portion  414  composed of a first material (e.g., graphite) encased, wrapped or enclosed with a second seal portion  416  composed of a second material (e.g., stainless steel) different than the first material. For example, the first seal portion  414  defines a core or an annular ring  418  and is substantially similar to the first seal portion  302  of the example rotary valve  100  of  FIGS. 1-4 . 
     The second seal portion  416  of the illustrated example includes a blowout prevention or locking feature  420 . More specifically, the second seal portion  416  defines an annular strip, sheet or sheath  422  (e.g., a unitary strip) that includes an edge  424  (e.g., an outer edge) wrapped, crimped or otherwise formed around at least a portion of the first seal portion  414 , and an intermediate portion  426  (e.g., a strip of material or a circular plate) extending across at least a portion of an opening  428  defined by the annular ring  418 . For example, the intermediate portion  426  of the second seal portion  416  forms a substantially circular plate to attach or clamp the seal  402  to the flow control member  404 . More specifically, the intermediate portion  426  is clamped or captured between a wall or surface  406   a  of the retainer  406  and a wall or surface  408   a  the body  408 . In some examples, the intermediate portion  426  may include one or more openings  430  to receive a fastener  432  of the retainer  406 . 
     During operation, a temporary suction or vacuum may occur at an interface between the seal  402  and a seating surface  434  when the flow control member  404  is moved to an open position (e.g., moves away from the seating surface  434  of the rotary valve  400 ) while exposed to high pressure fluids. As a result, there is a risk of the seal  402  being loosened, sucked or pulled out from the sealing cavity  410  by the fluid forces (e.g., a vacuum) overcoming the frictional or clamping forces provided by the retainer  406  and the body  408 . In some instances, such blowout can result in the loss of tight shut-off capability, thereby allowing fluid to flow through the rotary valve  400  when the flow control member  404  is in sealing engagement the seating surface  434  of the rotary valve  400 . 
     However, the intermediate portion  426  being clamped between the retainer  406  and the body  408  of the flow control member  404  reduces the risk of the seal  402  becoming loose or dislodged from the sealing cavity  410  of the flow control member  404 . Therefore, the intermediate portion  426  of the second seal portion  416  provides a blowout prevention feature by increasing a clamping or holding force provided by the retainer  406  and the body  408  to significantly reduce the likelihood of the seal  402  (e.g., the first seal portion  416 ) becoming loose or dislodged from the sealing cavity  410  when the rotary valve  400  is moved to an open position while exposed to process fluids having relatively high pressures. 
       FIG. 6  illustrates another example rotary valve  600  constructed in accordance with the teachings disclosed herein. The example rotary valve  600  includes a flow control member  602  having a retainer  604  coupled to a body  606  of the flow control member  602  to define a sealing cavity  608  about a peripheral edge  610  of the retainer  604  and/or the body  606 . A seal  612  of the illustrated example is positioned or clamped within the sealing cavity  608 . The seal  612  includes a first seal portion  614  composed of a first material (e.g., graphite) encased, wrapped or enclosed with a second seal portion  616  composed of a second material (e.g., stainless steel) different than the first material. 
     Similar to the rotary valve  400  of  FIGS. 4 and 5 , the example seal  612  of the illustrated example includes a blowout prevention or locking feature  618  to reduce the risk of the seal  612  loosening or becoming dislodged from the sealing cavity  608  of the flow control member  602  when the rotary valve  600  is exposed to high pressure and/or high velocity process fluids. In the illustrated example, both the first and second seal portions  614 ,  616  define the locking feature  618 . The first seal portion  614  defines a core having annular ring-shaped profile. The first seal portion  614  also defines a protruding shoulder, lip or leg  620  to help retain the seal  612  within the sealing cavity  608  of the flow control member  602 . In particular, the first seal portion  614  defines an L-shaped cross-sectional profile. The second seal portion  616  (e.g., a relatively thin strip of material composed of metal) wraps around the shoulder portion  620  of the first seal portion  614 . 
     The retainer  604  of the illustrated example includes a groove, slot or channel  622  to receive the shoulder  620  of the first seal portion  614  when the retainer  604  is coupled to the body  606 . As a result, the shoulder  620  of the first seal portion  614  engages a shoulder or wall  624  defined by the channel  622  to help retain or maintain the seal  612  in the sealing cavity  608  during operation of the rotary valve  600 . In other examples, the body  606  may include a groove or channel instead of the retainer  604  to receive the shoulder  620  of the first seal portion  614 . In yet other examples, the seal  612  may include another shoulder or leg (e.g., opposite and similar to the shoulder  620 ) such that both the channel  622  in the retainer  604  and a channel in the body  606  receive respective shoulders of the seal  612  to help retain the seal  612  in the sealing cavity  608  (e.g., a T-shaped seal). 
       FIG. 7  is an enlarged view of a portion of the example rotary valve  600  of  FIG. 6 , but implemented with another example seal  700 . The example seal  700  of  FIG. 7  includes a blowout prevention or locking feature  702  that is a combination of the locking feature  420  of  FIGS. 4 and 5  and the locking feature  618  of  FIG. 6 . More specifically, the seal  700  includes a first seal portion  704  that is encased with a second seal portion  706 . The first seal portion  704  includes a lip or shoulder  708  similar to the shoulder  620  of the seal  612  shown in  FIG. 6  and the second seal portion  706  includes an intermediate portion  710  similar to the intermediate portion  426  of the example seal  402  of  FIGS. 4 and 5 . 
       FIG. 8  illustrates another example rotary valve  800  disclosed herein. As shown in  FIG. 8 , the rotary valve  800  includes a movable flow control member  802  (e.g., a movable disk) positioned within a passageway  804  defined by a valve body  806  of the rotary valve  800  at which a relatively high pressure fluid may be presented. The rotary valve  800  includes a retainer ring  808  coupled to the valve body  806  to retain a seal ring assembly  810  within the valve body  806 . 
     To control the flow of process fluid through the passageway  804 , the flow control member  802  is operatively coupled to an actuator (not shown)(e.g., a manual actuator, a pneumatic actuator, etc.) via a valve shaft  812 . For example, the actuator moves the flow control member  802  relative to the seal ring assembly  810  in response to a control signal from a process controller, which may be part of a distributed control system (neither of which are shown). During operation, the actuator moves or rotates the flow control member  802  relative to the seal ring assembly  810  between a closed position to prevent fluid flow through the passageway  804  and an open position to allow fluid flow through the passageway  804 . 
       FIG. 9  is a cross-sectional view of a portion of the example rotary valve  800  of  FIG. 8  shown in a closed position  902 . In the closed position  902 , a sealing edge  904  (e.g., a peripheral edge) of the flow control member  802  sealingly engages the seal ring assembly  810  to prevent or restrict fluid flow through the passageway  804 . The seal ring assembly  810  of the illustrated example includes a seal  906  coupled to a carrier  908 . The carrier  908  may be composed of metal (e.g., stainless steel) and provides a spring or biasing effect to the seal  906 . In the illustrated example, a portion of the carrier  908  is positioned or clamped between the retainer  808  and the valve body  806  and couples the seal  906  to the valve body  806 . 
     As the flow control member  802  moves or rotates to the closed position  902 , the sealing edge  904  of the flow control member  802  engages or slides against the seal  906  and into the closed position  902 . The carrier  908  allows the seal  906  to compress or deflect as the flow control member  802  is rotated into the closed position  902  and the carrier  908  biases the seal  906  radially inward (e.g., toward a center of the valve body  806 ) and against the sealing edge  904  of the flow control member  802  to create a sufficiently tight seal between the seal  906  and the sealing edge  904 . Additionally, the example seal  906  and the carrier  908  provide a pressure-assisted seal. In particular, a pressure differential across the flow control member  802  provided by an inlet pressure that is greater than an outlet pressure provides an unbalanced force at an inlet side of the carrier  908  and the seal  906  that helps assist or bias (e.g., push) the seal  906  against the sealing edge  904 . 
       FIG. 10  illustrates an enlarged portion of the example rotary valve  800  of  FIGS. 8 and 9 . The seal  906  of the illustrated example includes a first seal portion  1002  composed of a first material and a second seal portion  1004  composed of a second material different than the first material. For example, the first seal portion  1002  is an inner core composed of graphite material and the second seal portion  1004  is an outer layer or protective sheath composed of metal (e.g., stainless steel, a nickel based alloy, etc.). More specifically, the first seal portion  1002  of the illustrated example is substantially encased or enclosed by the second seal portion  1004 . Further, the second seal portion  1004  is relatively thin compared to a thickness of the first seal portion  1002 . The seal  906  of the illustrated example is substantially similar to the seal  118  disclosed in connection with  FIGS. 1-4  and the structure and function is substantially similar to the structure and function of the example seal  118 . For example, in operation, the second seal portion  1004  protects the first seal portion  1002  from damage and/or erosion when the seal  906  is exposed to process fluids having relatively high temperatures and/or pressures or velocities that would otherwise damage and/or erode the first seal portion  1002  absent the second seal portion  1004 . As shown in the illustrated example, the seal  906  is attached to an end  1006  of the carrier  908  via a weld  1008 . However, in other examples, the seal  906  may be coupled to the carrier  908  via a mechanical fastener, a chemical fastener such as adhesive, and/or any other suitable fastener(s) or method(s). 
     The example seals disclosed herein are not limited to rotary valves. In some examples, the seals disclosed herein may be employed with linear valves such as sliding stem valves. For example,  FIG. 11  illustrates a linear valve  1100  that may be configured with any one of the example seals  118 ,  402 ,  612  and  700  disclosed herein. The linear valve  1100  includes a valve plug  1102  positioned within a fluid flow passageway  1104  of a valve body  1106  and moves relative to a valve seat  1108  to control the flow of fluid through the passageway  1104 . The valve plug  1102  of the illustrated example includes a retainer  1110  coupled to a plug body  1112 . The retainer  1110  and the plug body  1112  define a sealing cavity  1114  to receive a seal  1116 . For example, the seal  1116  of the illustrated example is substantially similar to the seal  402  of  FIGS. 4 and 5 . The retainer  1110  clamps or otherwise couples the seal  1116  to the plug body  1112 . In other examples, the retainer  1110  and/or the plug body  1112  may be configured to receive any one of the example seals  118 ,  612  and  700  disclosed herein. 
       FIGS. 12A and 12B  illustrate another example linear valve  1200  that may be configured with an example seal  1202  disclosed herein. In the illustrated example, the linear valve  1200  includes a valve body  1204  defining a fluid flow passageway  1206 . A seat ring  1208  is positioned within the passageway  1206  and includes an opening  1210  defining an orifice of the passageway  1206 . A flow control member  1212  moves within a retainer or cage  1214  and relative to the seat ring  1208  to control fluid flow through the valve  1200 . Referring to  FIG. 12B , the cage  1214  is engaged with or coupled to the seat ring  1208  to retain the seat ring  1208  in the valve body  1204 . In the illustrated example, the cage  1214  includes a recessed portion  1216  (e.g., a notched portion adjacent an end of the cage  1214 ) to define a sealing cavity  1218  to receive the seal  1202 . Thus, the cage  1214  clamps or otherwise holds the seal  1202  against the seat ring  1208 . The seal  1202  of the illustrated example includes a first portion or sheath  1220  substantially surrounding a second portion or core  1222  and is captured between respective clamping surfaces  1214   a ,  1208   a  of the cage  1214  and the seat ring  1208  to help retain the seal  1202  in the sealing cavity  1218 . In other examples, the cage  1214  and/or the seat ring  1208  may be configured to receive any one of the example seals  118 ,  612  and  700  disclosed herein. 
     Although certain example methods, apparatus and articles of manufacture have been disclosed 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 claims of this patent.