Abstract:
A fluid regulating device includes a valve disc and a valve port adapted to provide a secondary seal during an obstructed closing operation, whereby the valve disc directly engages a housing component of the valve port to maximize the integrity of the secondary seal and advantageously reduce the size and complexity of existing valve ports. The valve port comprises a housing and a cartridge slidably disposed in the housing. The valve disc directly engages a primary seat carried by the cartridge during a normal closing operation. During an obstructed closing operation, however, the cartridge is pushed into the housing such that the valve disc directly engages a secondary seat carried by the housing at a location that is downstream of the cartridge.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The priority benefit of U.S. Provisional Patent Application No. 60/913,121, entitled “Secondary Seat for Gas Regulator,” filed Apr. 20, 2007, is claimed and the entire contents thereof are expressly incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to gas regulators, and more particularly, to gas regulators having regulator valves with primary and secondary seats for closing the flow of fluid through the regulator. 
     BACKGROUND 
     The pressure at which typical gas distribution systems supply gas may vary according to the demands placed on the system, the climate, the source of supply, and/or other factors. However, most end-user facilities equipped with gas appliances such as furnaces, ovens, etc., require the gas to be delivered in accordance with a predetermined pressure, and at or below a maximum capacity of a gas regulator that may be installed in the system. Such gas regulators are implemented into these distribution systems to ensure that the delivered gas meets the requirements of the end-user facilities. Conventional gas regulators generally include a closed-loop control actuator for sensing and controlling the pressure of the delivered gas. 
     In addition to a closed loop control, some conventional gas regulators include a relief valve. The relief valve is adapted to provide over pressure protection when the regulator or some other component of the fluid distribution system fails, for example. Accordingly, in the event the delivery pressure rises above a predetermined threshold pressure, the relief valve opens to exhaust at least a portion of the gas to the atmosphere, thereby reducing the pressure in the system. 
       FIGS. 1 and 1A  depict one conventional gas regulator  10 . The regulator  10  generally comprises an actuator  12  and a regulator valve  14 . The regulator valve  14  defines an inlet  16 , an outlet  18 , and a throat  11 . The inlet  16  is for receiving gas from a gas distribution system, for example. The outlet  18  is for delivering gas to an end-user facility such as a factory, a restaurant, an apartment building, etc. having one or more appliances, for example. Additionally, the regulator valve  14  includes a valve port  36  carried by the throat  11  and disposed between the inlet  16  and the outlet  18 . Gas must pass through the valve port  36  to travel between the inlet  16  and the outlet  18  of the regulator valve  14 . 
     The actuator  12  is coupled to the regulator valve  14  to ensure that the pressure at the outlet  18  of the regulator valve  14 , i.e., the outlet pressure, is in accordance with a desired outlet or control pressure. The actuator  12  is therefore in fluid communication with the regulator valve  14  via a valve mouth  34  and an actuator mouth  20 . The actuator  12  includes a control assembly  22  for sensing and regulating the outlet pressure of the regulator valve  14 . Specifically, the control assembly  22  includes a diaphragm  24 , a piston  32 , and a control arm  26  having a valve disc  28 . The conventional valve disc  28  includes a generally cylindrical body  25  and a sealing insert  29  fixed to the body  25 . The diaphragm  24  senses the outlet pressure of the regulator valve  14 . The control assembly  22  further includes a control spring  30  in engagement with a top-side of the diaphragm  24  to offset the sensed outlet pressure. Accordingly, the desired outlet pressure, which may also be referred to as the control pressure, is set by the selection of the control spring  30 . 
     The diaphragm  24  is operably coupled to the control arm  26 , and therefore the valve disc  28 , via the piston  32 , controls the opening of the regulator valve  14  based on the sensed outlet pressure. For example, when an end user operates an appliance, such as a furnace that places a demand on the gas distribution system downstream of the regulator  10 , the outlet flow increases, thereby decreasing the outlet pressure. Accordingly, the diaphragm  24  senses this decreased outlet pressure. This allows the control spring  30  to expand and move the piston  32  and the right-side of the control arm  26  downward, relative to the orientation of  FIG. 1 . This displacement of the control arm  26  moves the valve disc  28  away from the valve port  36  to open the regulator valve  14 . So configured, the appliance may draw gas through the valve port  36  toward the outlet  18  of the regulator valve  14 , as demand may be required for operation. 
       FIG. 1A  depicts the conventional valve port  36  of the conventional regulator  10 . The valve port  36  generally includes a housing  60 , a cartridge  62 , and a spring  64 . The cartridge  62  is slidably disposed within the housing  60  such that the valve port  36  is adapted for providing both a primary seal and a back-up, or secondary, seal, as will be described. The spring  64  biases the cartridge  62  into the position depicted in  FIG. 1A , which corresponds to the valve port  36  providing the primary seal. 
     The housing  60  includes a hollow, generally cylindrical housing having a hexagonal nut portion  66 , a body portion  68 , and a curtain portion  70 . The body portion  68  includes an internal bore  74  defining a step  76  and a ring-shaped recess  78 . The ring-shaped recess  78  contains an o-ring  83  for providing a pneumatic seal between the housing  60  and the cartridge  62 . The body portion  68  further includes a plurality of external threads  72  for being threadably coupled into the regulator valve  14 , as depicted. The nut portion  66  of the housing  62  is therefore adapted to be engaged by a tool such as a pneumatic ratchet to install the valve port  36  into the throat  11  of the regulator valve  14 . The curtain portion  70  includes a plate  80  spaced from the body portion  68  of the housing  62  by a pair of legs  82 . The plate  80  carries a secondary seat  71  including a rubber surface  73 , for example. So configured, the curtain portion  70  defines a pair of windows  84  in the housing  60 . The windows  84  allow for the flow of gas into the valve port  36  and through the regulator valve  14 . 
     The cartridge  62  of the conventional valve port  36  depicted in  FIG. 1A  includes a hollow, generally cylindrical member defining a central orifice  88  therethrough. The cartridge  62  includes a first portion  62   a  and a second portion  62   b . A diameter of the first portion  62   a  is slightly smaller than a diameter of the second portion  62   b . Therefore, a shoulder  86  is disposed between the first and second portions  62   a ,  62   b . The shoulder  86  abuts the step  76  of the housing  60  in the depicted position, thereby limiting the displacement of the cartridge  62  in the direction indicated by the arrow A in  FIG. 1A . 
     Moreover, the first portion  62   a  of the cartridge  62  includes an outlet end  90  defining an externally chamfered surface  92  and a primary seat  94 . The primary seat  94  is adapted to be sealingly engaged by the valve disc  28 , as depicted, to stop the flow of gas through the regulator valve  14 . The second portion  62   b  includes an inlet end  96  defining an internally chamfered surface  98  and a seating surface  95 . The seating surface  95  is adapted to engage the rubber surface  73  of the secondary seat  71  upon the primary seat  94  failing to provide an adequate seal to close the valve port  36 . 
     For example, during use, debris or some other type of foreign material may become lodged between the valve disc  28  and the primary seat  94  when the valve disc  28  attempts to seal against the primary seal  94 . Thus, the primary seal fails to stop the flow of gas through the valve port  36  and the pressure downstream of the regulator  10 , i.e., the outlet pressure, increases. This increase is sensed by the diaphragm  24  which further causes the valve disc  28  to be forced toward the valve port  36 . This force eventually overcomes the force of the spring  64  in the valve port  36  and displaces the cartridge  62  relative to the housing  60  in a direction opposite the arrow A. Continued displacement causes the seating surface  95  on the second portion  62   b  of the cartridge  62  to engage the rubber surface  73  of the secondary seat  71  carried by the plate  80  of the curtain portion  70 . So configured, the secondary seat  71  of the cartridge  62  seals the inlet end  96  and blocks the flow of gas from passing through the windows  84  in the housing  60 , thereby preventing gas from flowing through the regulator valve  14 . Moreover, the o-ring  83  seals any path for gas to penetrate the windows  84  and leak between the cartridge  62  and the housing  60  of the valve port  36 . Once a downstream demand is placed back on the system however, the diaphragm  24  senses a decrease in outlet pressure and moves the valve disc  28  away from the valve port  36 . The spring  64  biases the cartridge  62  back to the position depicted in  FIG. 1A  and any debris previously lodged between the valve disc  28  and the primary seat  94  likely releases and flows downstream of the regulator valve  14 . Thus, the conventional regulator  10  and the conventional valve port  36  provide a secondary seal to back-up any failure or obstruction with the primary seal. 
     Additionally, as mentioned above, the conventional regulator  10  depicted in  FIG. 1  further functions as a relief valve. Specifically, the control assembly  22  includes a relief spring  40  and a release valve  42 . The diaphragm  24  includes an opening  44  through a central portion thereof and the piston  32  includes a sealing cup  38 . The relief spring  40  is disposed between the piston  32  and the diaphragm  24  to bias the diaphragm  24  against the sealing cup  38  to close the opening  44 , during normal operation. Upon the occurrence of a failure such as a break in the control arm  26 , for example, the control assembly  22  is no longer in direct control of the valve disc  28  and the inlet flow will move the valve disc  28  into an extreme open position. This allows a maximum amount of gas to flow into the actuator  12 . Thus, as the gas fills the actuator  12 , pressure builds against the diaphragm  24  forcing the diaphragm  24  away from the sealing cup  38 , thereby exposing the opening  44 . The gas therefore flows through the opening  44  in the diaphragm  24  and toward the release valve  42 . The release valve  42  includes a valve plug  46  and a release spring  54  biasing the valve plug  46  into a closed position, as depicted in  FIG. 1 . Upon the pressure within the actuator  12  and adjacent the release valve  42  reaching a predetermined threshold pressure, the valve plug  46  displaces upward against the bias of the release spring  54  and opens, thereby exhausting gas into the atmosphere and reducing the pressure in the regulator  10 . 
     One consideration in selecting a regulator for use in a particular application includes maximizing flow capacity at the set outlet, or control, pressure. However, due to structural constraints, the conventional valve port  36  is limited as to how large of a diameter the orifice  88  may have. For example, one conventional embodiment of the valve port  36  may include an orifice  88  with a maximum diameter of seven-eighths of an inch, i.e., ⅞″. 
     For example, the dimensions of the housing  60  of the valve port  36  are oftentimes prescribed by the amount of torque used to install the valve port  36  into the regulator valve  14 . Specifically, as mentioned above, the valve port  36  may be installed with a pneumatic ratchet. If the sidewall of the body portion  68  of the housing  60  adjacent to the threads  72  is too thin, then the torque generated by the pneumatic ratchet may shear the housing  60 . Accordingly, the thickness of the housing  60 , which impacts the diameter of the orifice  88  in the cartridge  62 , and therefore the maximum flow capacity, is limited based on the prescribed thickness of the sidewall of the housing  60 . Additionally, as described above, the conventional port  36  requires the recess  78  in the housing  60  for accommodating the o-ring  83 , which prevents leakage when utilizing the secondary seal. The position and geometry of the recess  78  may further compromise the structural integrity of the sidewall of the housing  60 , and therefore, must be considered in designing the thickness of the housing  60 . 
     Moreover, to maximize flow capacity of the valve port  36 , the windows  84  must be positioned substantially within the flow of gas from the inlet  16 . Thus, housing  60  of the valve port  36  is dimensioned such that the curtain portion  70  and the plate  80  carrying the secondary seat  71  extend well beyond the throat  11  of the regulator valve  14 . So configured, the cartridge  62  must be suitably dimensioned to slide from the position depicted in  FIG. 1A  to a position where the seating surface  95  is in engagement with the secondary seat  71  upon the occurrence of a failure, as described above. Such dimensions add to the size and cost of the overall valve port  36 . 
     SUMMARY 
     The present invention provides a fluid regulating device and/or a valve port for a fluid regulating device. The fluid regulating device generally comprises an actuator and a valve body. The actuator includes a moveable valve disc. The valve port is disposed within the valve body. The actuator displaces the valve disc relative to the valve port for controlling the flow of fluid through the valve body. The valve port includes a cartridge slidably disposed within a housing. The cartridge includes a primary seat for engagement with the valve disc to provide a primary seal to stop flow through the valve body when there is no demand on the system. Moreover, the housing includes a nose portion such that in the event there is an obstruction between the valve disc and the primary seat, the cartridge slides into the housing and the valve disc sealingly engages the nose portion on the housing to provide a back-up seal or secondary seal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side cross-sectional view of a conventional regulator including a conventional valve port; 
         FIG. 1A  is a side cross-sectional view of a regulator valve of the regulator of  FIG. 1  including the conventional valve port and taken from circle I-A of  FIG. 1 ; 
         FIG. 2  is a side cross-sectional view of a regulator including a first embodiment of a valve port constructed in accordance with the principles of the present invention; 
         FIG. 2A  is a side cross-sectional view of a regulator valve of the regulator of  FIG. 2  illustrating the valve port providing a primary seal and taken from circle II-A of  FIG. 2 ; 
         FIG. 2B  is a side cross-sectional view of the regulator valve of  FIG. 2A  illustrating the valve port providing a secondary seal; 
         FIG. 3  is a side cross-sectional view of a second embodiment of a valve port constructed in accordance with the principles of the present invention; 
         FIG. 4  is a partial side cross-sectional view of a third embodiment of a valve port constructed in accordance with the principles of the present invention; and 
         FIG. 5  is a partial side cross-sectional view of a fourth embodiment of a valve port constructed in accordance with the principles of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  depicts a gas regulator  100  constructed in accordance with one embodiment of the present invention. The gas regulator  100  generally includes an actuator  102  and a regulator valve  104 . The regulator valve  104  includes an inlet  106  for receiving gas from a gas distribution system, for example, and an outlet  108  for delivering gas to a facility having one or more appliances, for example. The actuator  102  is coupled to the regulator valve  104  and includes a control assembly  122  having a control element  127 . During a first or normal operational mode, the control assembly  122  senses the pressure at the outlet  108  of the regulator valve  104 , i.e., the outlet pressure, and controls a position of the control element  127  such that the outlet pressure approximately equals a predetermined control pressure. Additionally, upon the occurrence of a failure in the system such as a breakage of one of the components of the control assembly  122 , the regulator  100  performs a relief function that is generally similar to the relief function described above with reference to the relief valve  42  of the regulator  10  depicted in  FIG. 1 . 
     With continued reference to  FIG. 2 , the regulator valve  104  further defines a throat  110  and a valve mouth  112 . The throat  110  is disposed between the inlet  106  and the outlet  108  accommodates a valve port  136 . The valve mouth  112  defines an opening  114  disposed along an axis that is generally perpendicular to an axis of the inlet  106  and outlet  108  of the regulator valve  104 . The valve port  136  defines a flow path  148  along an elongated orifice  288  (identified in  FIG. 2A ) that extends between an inlet end  150  and an outlet end  152 . Gas must travel through the orifice  288  in the valve port  136  to travel between the inlet  106  and the outlet  108  of the regulator valve  104 . The valve port  136  is removable from the regulator valve  104  such that it may be replaced with a different valve port having a different configuration to tailor operational and flow characteristics of the regulator valve  104  to a specific application. 
     The actuator  102  includes a housing  116  and the control assembly  122 , as mentioned above. The housing  116  includes an upper housing component  116   a  and a lower housing component  116   b  secured together with a plurality of fasteners, for example. The lower housing component  116   b  defines a control cavity  118  and an actuator mouth  120 . The actuator mouth  120  is connected to the valve mouth  112  of the regulator valve  104  to provide fluid communication between the actuator  102  and the regulator valve  104 . In the disclosed embodiment, the regulator  100  includes a collar  111  securing the mouths  112 ,  120  together. The upper housing component  116   a  defines a relief cavity  134  and an exhaust port  156 . The upper housing component  116   a  further defines a tower portion  158  for accommodating a portion of the control assembly  122 , as will be described. 
     The control assembly  122  includes a diaphragm subassembly  121 , a disc subassembly  123 , and a release valve  142 . The diaphragm subassembly  121  includes a diaphragm  124 , a piston  132 , a control spring  130 , a relief spring  140 , a combination spring seat  164 , a relief spring seat  166 , a control spring seat  160 , and a piston guide  159 . 
     More particularly, the diaphragm  124  includes a disc-shaped diaphragm defining an opening  144  through a central portion thereof. The diaphragm  124  is constructed of a flexible, substantially air-tight, material and its periphery is sealingly secured between the upper and lower housing components  116   a ,  116   b  of the housing  116 . The diaphragm  124  therefore separates the relief cavity  134  from the control cavity  118 . 
     The combination spring seat  164  is disposed on top of the diaphragm  124  and defines an opening  170  positioned concentric with the opening  144  in the diaphragm  124 . As depicted in  FIG. 2 , the combination spring seat  164  supports the control spring  130  and the relief spring  140 . 
     The piston  132  of the disclosed embodiment includes a generally elongated rod-shaped member having a sealing cup portion  138 , a yoke  172 , a threaded portion  174 , and a guide portion  175 . The sealing cup portion  138  is concaved and generally disc-shaped and extends circumferentially about a mid-portion of the piston  132 , and is located just below the diaphragm  124 . The yoke  172  includes a cavity adapted to accommodate a coupler  135  which connects to a portion of the disc subassembly  123  to enable attachment between the diaphragm subassembly  121  and the disc subassembly  123 , as will be described. 
     The guide portion  175  and the threaded portion  174  of the piston  132  are disposed through the openings  144 ,  170  in the diaphragm  124  and the combination spring seat  164 , respectively. The guide portion  175  of the piston  132  is slidably disposed in a cavity in the piston guide  159 , which maintains the axial alignment of the piston  132  relative to the remainder of the control assembly  122 . The relief spring  140 , the relief spring seat  166 , and a nut  176 , are disposed on the threaded portion  174  of the piston  132 . The nut  176  retains the relief spring  140  between the combination spring seat  164  and the relief spring seat  166 . The control spring  130  is disposed on top of the combination spring seat  164 , as mentioned, and within the tower portion  158  of the upper housing component  116   a . The control spring seat  160  is threaded into the tower portion  158  and compresses the control spring  130  against the combination spring seat  164 . In the disclosed embodiment, the control spring  130  and the relief spring  140  include compression coil springs. Accordingly, the control spring  130  is grounded against the upper housing component  116   a  and applies a downward force to the combination spring seat  164  and the diaphragm  124 . The relief spring  140  is grounded against the combination spring seat  164  and applies an upward force to the relief spring seat  166 , which in turn is applied to the piston  132 . In the disclosed embodiment, the force generated by the control spring  130  is adjustable by adjusting the position of the control spring seat  160  in the tower portion  158 , and therefore the control pressure of the regulator  100  is also adjustable. 
     The control spring  130  acts against the pressure in the control cavity  118 , which is sensed by the diaphragm  124 . As stated, this pressure is the same pressure as that which exists at the outlet  108  of the regulator valve  104 . Accordingly, the force applied by the control spring  130  sets the outlet pressure to a desired, or control pressure for the regulator  100 . The diaphragm subassembly  121  is operably coupled to the disc subassembly  123 , as mentioned above, via the yoke portion  172  of the piston  132  and the coupler  135 . 
     Specifically, the disc subassembly  123  includes a control aim  126  and a stem guide  162 . The control arm  126  includes a stem  178 , a lever  180 , and the control element  127 . The control element  127  of the disclosed embodiment includes a valve disc  128  with a seating surface  188 . The valve disc  128  may be similar to the valve disc  28  described above with reference to  FIG. 1 , for example. The stem  178 , lever  180 , and valve disc  128  are constructed separately and assembled to form the control arm  126 . Specifically, the stem  178  is a generally linear rod having a nose  178   a  and a recess  178   b , which in the disclosed embodiment is generally rectangular. The lever  180  is a slightly curved rod and includes a fulcrum end  180   a  and a free end  180   b . The fulcrum end  180   a  includes an aperture  184  receiving a pivot pin  186  carried by the lower housing component  116   b . The fulcrum end  180   a  also includes a knuckle  187  having an elliptical cross-section and disposed within the recess  178   b  of the stem  178 . The free end  180   b  is received between a top portion  135   a  and a pin  135   b  of the coupler  135  that is attached to the yoke  172  of the piston  132 . Thus, the coupler  135  operably connects the disc subassembly  123  to the diaphragm subassembly  121 . 
     The stem guide  162  includes a generally cylindrical outer portion  162   a , a generally cylindrical inner portion  162   b , and a plurality of radial webs  162   c  connecting the inner and outer portions  162   b ,  162   a . The outer portion  162   a  of the stem guide  162  is sized and configured to fit within the mouths  112 ,  120  of the regulator valve  104  and lower housing component  116   b , respectively. The inner portion  162   b  is sized and configured to slidably retain the stem portion  178  of the control arm  126 . Thus, the stem guide  162  serves to maintain the alignment of the regulator valve  104 , the actuator housing  116 , and the control assembly  122 , and more particularly, the stem  178  of the control arm  126  of the control assembly  122 . 
       FIG. 2  depicts the regulator  100  in a normally operational closed position, where there is no demand placed on the system downstream of the regulator  100 . Therefore, the seating surface  188  of the valve disc  128  sealingly engages the outlet end  152  of the valve port  136 . So configured, gas does not flow through the valve port  136 . This configuration is achieved because the outlet pressure, which corresponds to the pressure in the control cavity  118  of the housing  116  and sensed by the diaphragm  124 , is greater than the force applied by the control spring  130 . Accordingly, the outlet pressure forces the diaphragm  124  and the piston  132  into the closed position depicted. 
     However, in the event that an operating demand is placed on the gas distribution system, e.g., a user begins operating an appliance such as a furnace, a stove, etc., the appliance draws gas flow from the control cavity  118  of the regulator  100 , thereby reducing the pressure that is sensed by the diaphragm  124 . As the pressure sensed by the diaphragm  124  decreases, a force imbalance occurs between a control spring force and an outlet pressure force on the diaphragm  124  such that the control spring  130  expands and displaces the diaphragm  124  and piston  132  downward, relative to the housing  116 . This causes the lever  180  to pivot in the clockwise direction about the pivot pin  186 , which, in turn, rotates the knuckle  187  relative to the recess  178   b  in the stem  178 . This moves the valve disc  128  away from the outlet end  152  of the valve port  136  to open the regulator valve  104 . So configured, the gas distribution system is able to deliver gas to the downstream appliance through the regulator valve  104  at a control pressure that is set by the control spring  130 . Additionally, the diaphragm subassembly  121  continues to sense the outlet pressure of the regulator valve  104 . As long as the outlet pressure remains approximately equal to the control pressure, the control assembly  122  will balance the valve disc  128  in an open position away from the outlet end  152  of the valve port  136 . 
     For example, if the outlet flow, i.e., the demand, increases, thereby decreasing the outlet pressure below the control pressure, the diaphragm senses the decreased outlet pressure and the spring  130  expands and moves the diaphragm  124  and piston  132  downward to further move the control element  127  away from the valve port  136  and further open the regulator valve  104 . Alternatively, however, if the outlet flow, i.e., the demand, decreases, thereby increasing the outlet pressure above the control pressure set by the control spring  130 , the diaphragm  124  senses the increased outlet pressure and moves upward against the bias of the control spring  130 . Furthermore, in the event that the downstream demand completely stops, gas will continue to flow through the regulator valve  104  such that the downstream pressure sufficiently increases to move the valve disc  128  into engagement with the outlet end  152  of the valve port  136 . 
       FIG. 2A  depicts one embodiment of the valve port  136  constructed in accordance with the principles of the present invention. The valve port  136  generally includes a housing  260 , a cartridge  262 , and a spring  264 . The cartridge  262  is slidably disposed within the housing  260  between a first position, which is depicted in  FIG. 2A , and a second position, which is depicted in  FIG. 2B . So configured, the valve port  136  is adapted for providing both a primary seal and a back-up, or secondary, seal, as will be described. The spring  264  biases the cartridge  262  into the first position depicted in  FIG. 2A , which corresponds to a position for providing the primary seal. 
     The housing  260  includes a generally cylindrical housing having a nose  265 , a hexagonal nut portion  266 , a body portion  268 , and a curtain portion  270 . The nose  265 , the nut portion  266 , and the body portion  268  cooperatively, or in combination, define an internal cavity  274 . The internal cavity  274  includes a first portion  274   a  and a second portion  274   b . The diameter of the first portion  274   a  is smaller than the diameter of the second portion  274   b . Thus, the body portion  268  includes a step surface  276  disposed between the first and second portions  274   a ,  274   b.    
     The first portion  274   a  extends longitudinally from the nose  265  of the housing  260 , through the nut portion  266 , and terminates at the second portion  274   b  of the internal cavity  274 . The second portion  274   b  extends longitudinally from the termination of the first portion  274   a  to the curtain portion  270  of the housing  260 . The curtain portion  270  includes a plate  280  spaced from the body portion  268  of the housing  262  by a pair of legs  282 . The plate  280  of the disclosed embodiment includes a solid circular plate that serves as a spring seat  271 . So configured, the curtain portion  270  defines a pair of windows  284  in the housing  260  for allowing gas to flow into the valve port  136 . 
     Additionally, the body portion  268  further includes a plurality of external threads  272  for being threadably coupled into the throat  110  of the regulator valve  104 , as depicted. The nut portion  266  of the housing  262  is therefore adapted to be engaged by a tool such as a pneumatic ratchet to install the valve port  136  into the regulator valve  104 . 
     The cartridge  262  of the valve port  136  disclosed in  FIGS. 2 ,  2 A, and  2 B includes a conduit portion  262   a  and a flange portion  262   b . The conduit portion  262   a  is generally cylindrical and defines an elongated central orifice  288  along the flow path  148 . The central orifice  288  is adapted to accommodate the flow of fluid between the inlet  116  and the outlet  118  of the regulator valve  104 . Moreover, the conduit portion  262   a  carries the outlet end  152  of the valve port  136  and an externally chamfered surface  292 . The outlet end  152  serves as a primary seat  294 , which is adapted to be sealingly engaged by the valve disc  128  to stop the flow of gas through the regulator valve  104 , during a normally operational condition, as depicted in  FIG. 2A , for example. 
     The flange portion  262   b  is a solid disc-shaped member extending circumferentially about the conduit portion  262   a . The flange portion  262   b  includes a stop surface  285  and a spring seat surface  287 , which is opposite the stop surface  285 . The spring  264 , which may include a compression coil spring, is retained between the spring seat surface  287  of the flange portion  262   b  of the cartridge  262  and the spring seat  271  of the curtain portion  270  of the housing  260 . Thus, the spring  264  biases the cartridge  262  into the first position depicted in  FIGS. 2 and 2A , which includes the outlet end  152  of the cartridge  262  extending outward beyond the nose  265  of the housing  260 . In this position, the stop surface  285  abuts the step surface  276  of the housing  260  to limit the displacement of the cartridge  262  away from the spring  264 . 
       FIGS. 2A and 2B  depict one embodiment of the valve port  136  that may include a pneumatic seal such as an o-ring  283  positioned between the stop surface  285  of the cartridge  262  and the spring seat surface  276  of the housing  260 . Although not necessary, such an o-ring  283  can provide an added seal between the cartridge  262  and the housing  260  when the cartridge  262  is the first position, as depicted in  FIG. 2A . The o-ring  283  does not provide a sealing function when the cartridge  262  is in the second position, which includes the flange portion  262   b  of the cartridge  262  moved away and spaced from the step surface  276  of the housing  260  and the outlet end  152  of the cartridge  262  retracted into the nose  265  of the housing  260 , as depicted in  FIG. 2B . 
     As mentioned above, the housing  160  of the present embodiment of the valve port  136  includes a nose  265 . The nose  265  generally includes a raised portion extending from the nut portion  266  of the housing  260  adjacent to the first portion  274   a  of the internal cavity  274  and the outlet end  152  of the cartridge  262 . The nose  265  includes a first frustoconical  265   a  portion and a second frustoconical portion  265   b  disposed inside and concentric with the first frustoconical portion  265   a . The first frustoconical portion  265   a  converges away from the nut portion  266  of the housing  260  at a first angle α. The second frustoconical portion  265   b  converges away from the nut portion  266  of the housing  260  at a second angle β. In the disclosed embodiment, the first angle α is greater than the second angle β. However, in an alternative embodiment, the first angle α may be equal to or even less than the second angle β. In any respect, the second frustoconical portion  265   b , by virtue of extending further away from the nut portion  266  than the first frustoconical portion  265   a , defines a secondary seat  267 , which is adapted to be engaged by the valve disc  128  under certain failure conditions. 
     For example, during operation, debris or some other type of foreign material, which may be identified by reference numeral  101  in  FIG. 2B , may become lodged between the valve disc  128  and the primary seat  294  when the regulator  100  attempts to seal the valve disc  128  against the primary seat  294 . Thus, gas continues to flow through the valve port  136 , thereby increasing the pressure downstream of the regulator  100 , i.e., the outlet pressure. This increase is sensed by the diaphragm  124  which further causes the valve disc  128  to be forced toward the valve port  136 . This force eventually overcomes the force of the spring  264  in the valve port  136  and displaces the cartridge  262  relative to the housing  260 . Continued displacement causes the cartridge  262  to be forced into the second position, as depicted in  FIG. 2B , such that outlet end  152  of the cartridge  262  is retracted into the nose  265  and the valve disc  128  engages the secondary seat  267 . So configured, the valve disc  128  seals against the secondary seat  267  and prevents the flow of gas through the cartridge  262 , and therefore through the regulator valve  104 . 
     Thus, the regulator  100  and the valve port  136  of the embodiment depicted in  FIGS. 2 ,  2 A, and  2 B advantageously provides the secondary seat  267  on the housing  260  downstream of the cartridge  262 . This portion of the housing  260  is directly coupled to the regulator valve  104  and has more structural integrity than the conventional secondary seat  71 , which is supported by the curtain portion  70  of the conventional valve port  36  described above with reference to  FIGS. 1 and 1A . 
     Furthermore, the secondary seat  267  of the housing  260  of the valve port  136  eliminates any potential for a leakage path between the cartridge  262  and the housing  260  when the valve disc  128  engages the secondary seat  267 . In contrast, when the cartridge  62  of the conventional valve port  36  depicted in  FIGS. 1 and 1A  sealingly engages the secondary valve seat  71 , the o-ring  83  is required to prevent leakage between the cartridge  62  and the housing  60 . Moreover, the o-ring  83  of the conventional valve port  36  requires the recess  78 . As mentioned above, the recess  78  affects the structural integrity of the housing  60 , particularly with respect to installation with a tool such as a pneumatic ratchet. Specifically, the inclusion of the o-ring  83  and therefore the recess  78  requires a sidewall thickness for the housing  60  that could otherwise be reduced. This thickened sidewall of the conventional housing  60  limits the maximum diameter of the orifice  88  and therefore the maximum flow capacity of the valve port  36 . Accordingly, the potential range of flow capacities for the conventional valve port  36  is reduced. 
     Although, the valve port  136  of the present invention has been described as maybe including the o-ring  283 , the valve port  136  neither requires such an o-ring nor a recess that compromises the strength of the housing  260 . For example, the o-ring  283  is not positioned about an outer radial sidewall of the cartridge  262 , but rather, it is positioned between the stop surface  285  of the flange portion  262   b  and the step surface  276  of the housing  260 . So positioned, the o-ring  283  does not affect the thickness of the sidewall of the housing  260  in the manner that the recess  78  and o-ring  83  of the conventional valve port  36  affect the thickness of the conventional housing  60 . 
     Furthermore, the o-ring  283  only provides a pneumatic seal between the cartridge  262  and the housing  260  when the cartridge  262  is in the normal operating position depicted in  FIGS. 2 and 2A , for example. When the valve disc  128  moves the cartridge  262  into the housing  260  and engages the secondary seat  267 , as depicted in  FIG. 2B , the o-ring  283  provides no sealing function. In fact, as mentioned above, an alternative embodiment of the valve port  136  may not require such a pneumatic seal. 
     Therefore, because the valve port  136  of the present embodiment of the present invention does not require a pneumatic seal similar to the o-ring  83  of the conventional valve port  36 , the valve port  136  provides for a greater range of flow capacities, and more particularly, a greater maximum flow capacity. For example,  FIG. 3  depicts a second embodiment of a valve port  236  constructed in accordance with the principles of the present invention. The valve port  236  is similar to the valve port  136  described above with reference to  FIGS. 2A and 2B . 
     Specifically, the valve port  236  depicted in  FIG. 3  includes a housing  360 , a cartridge  362 , and a spring  364 . The cartridge  362  is slidably disposed within the housing  360  similar to the cartridge  262  discussed above with reference to  FIGS. 2A and 2B . So configured, the valve port  236  is adapted for providing both a primary seal and a back-up, or secondary, seal. The spring  364  biases the cartridge  362  into the position depicted in  FIG. 3 , which corresponds to a position for providing the primary seal. 
     The housing  360  includes a generally cylindrical housing having a nose  365 , a hexagonal nut portion  366 , a body portion  368 , and a curtain portion  370 . The nose  365 , the nut portion  366 , and the body portion  368  cooperatively, or in combination, define an internal cavity  374 . The internal cavity  374  includes a first portion  374   a  and a second portion  374   b . The diameter of the first portion  374   a  is only slightly smaller than the diameter of the second portion  374   b  in the embodiment of the valve port  236  depicted in  FIG. 3 . Thus, the body portion  368  includes a step surface  376  disposed between the first and second portions  374   a ,  374   b.    
     The first portion  374   a  extends longitudinally from the nose  365  of the housing  360 , through the nut portion  366 , and terminates at the second portion  374   b  of the internal cavity  374 . The second portion  374   b  extends longitudinally from the termination of the first portion  374   a  to the curtain portion  370  of the housing  360 . The curtain portion  370  includes a plate  380  spaced from the body portion  368  of the housing  362  by a pair of legs  382 . The plate  380  of the disclosed embodiment includes a solid circular plate that serves as a spring seat  371 . So configured, the curtain portion  370  defines a pair of windows  384  in the housing  360  for allowing gas to flow into the valve port  236 . 
     Additionally, the body portion  368  further includes a plurality of external threads  372  for being threadably coupled into the throat  110  of the regulator valve  104 , as depicted in  FIG. 2 , for example. The nut portion  366  of the housing  362  is therefore adapted to be engaged by a tool such as a pneumatic ratchet to install the valve port  236  into the regulator valve  104 . 
     The cartridge  362  of the valve port  236  disclosed in  FIG. 3  includes a conduit portion  362   a  and a flange portion  362   b . The conduit portion  362   a  is generally cylindrical and defines an elongated central orifice  388  along the flow path  148 . The central orifice  388  is adapted to accommodate the flow of fluid between the inlet  116  and the outlet  118  of the regulator valve  104 . Moreover, the conduit portion  362   a  carries the outlet end  152  of the valve port  236 , as described above with reference to  FIG. 2 , and an externally chamfered surface  392 . The outlet end  152  serves as a primary seat  394 , which is adapted to be sealingly engaged by the valve disc  128  to stop the flow of gas through the regulator valve  104 . 
     The flange portion  362   b  is a solid disc-shaped member extending circumferentially about the flow portion  362   a . The flange portion  362   b  includes a stop surface  385  and a spring seat surface  387 , which is opposite the stop surface  385 . The spring  364 , which may include a compression coil spring, is retained between the spring seat surface  387  of the flange portion  362   b  of the cartridge  362  and the spring seat  371  of the curtain portion  370  of the housing  360 . Thus, the spring  364  biases the cartridge  362  into the position depicted in  FIG. 3 . The stop surface  385  abuts the step surface  376  of the housing  360  to limit the displacement of the cartridge  362  away from the spring  364 . 
       FIG. 3  depicts an embodiment of the valve port  236  that does not include a pneumatic seal disposed between the cartridge  362  and the housing  360 . Such a pneumatic seal is not necessary, as discussed above with reference to the previous embodiment of the valve port  136  depicted in  FIGS. 2 ,  2 A and  2 B. 
     As mentioned above, the housing  360  of the present embodiment of the valve port  236  includes a nose  365 . The nose  365  generally includes a raised portion extending from the nut portion  366  of the housing  360  adjacent to the first portion  374   a  of the internal cavity  374  and the outlet end  152  of the valve port  236 . The nose  365  includes a first frustoconical  365   a  portion and a second frustoconical portion  365   b  disposed inside and concentric with the first frustoconical portion  365   a . The first frustoconical portion  365   a  converges away from the nut portion  366  of the housing  360  at a first angle α. The second frustoconical portion  365   b  converges away from the nut portion  366  of the housing  360  at a second angle β. In the disclosed embodiment, the first angle α is greater than the second angle β. However, in an alternative embodiment, the first angle α may be equal to or even less than the second angle β. In any respect, the second frustoconical portion  365   b , by virtue of extending further away from the nut portion  366  than the first frustoconical portion  365   a , defines a secondary seat  367 , which is adapted to be engaged by the valve disc  128  under certain failure conditions, such as debris becoming lodged between the valve disc  128  and the primary seat  394 , similar to that described above with reference to the previous embodiment of the valve port  136  depicted in  FIGS. 2 ,  2 A, and  2 B. 
     Accordingly, the diameter of the orifice  388  of the present embodiment of the valve port  236  is larger than the diameter of the orifice  288  of the valve port  136  described above with reference to  FIGS. 2 ,  2 A, and  2 B. Moreover, the diameter of the orifice  388  of the present embodiment of the valve port  236  is advantageously larger than the diameter of the orifice  88  of the conventional valve port  36  described above with reference to  FIGS. 1 and 1A . So configured, the valve port  236  of the embodiment depicted in  FIG. 3  has a flow capacity substantially greater than a flow capacity of the previous embodiment of the valve port  136 , as well as the conventional valve port  36 . 
     The increased diameter of the orifice  388  of the valve port  236  depicted in  FIG. 3  translates into an increased diameter of the conduit portion  362   a  of the cartridge  362 , as well as the nose  365  of the housing  360 . Nevertheless, the cartridge  362  and housing  360  of the embodiment depicted in  FIG. 3  operate in a similar manner to the cartridge  262  and housing  260  of the valve port  136  described with reference to  FIGS. 2 ,  2 A, and  2 B. 
     In one embodiment, the orifice  388  of the embodiment of the valve port  236  depicted in  FIG. 3  may have a maximum diameter of approximately one and three-eighths inches, i.e., 1⅜″. This is made possible by the elimination of the need for a recess for accommodating an o-ring between the outer radial surface of the cartridge  362  and the housing  360 , which correlates to a decrease in the overall thickness of the sidewall of the housing  360 . 
     Thus, the present invention advantageously provides for a versatile valve port having increased flow capacity and increased structural integrity while performing a secondary sealing function. While the various embodiments of the valve port  136 ,  236  constructed in accordance with the present invention have thus far been described as including a housing  260 ,  360  with a nose  265 ,  365  comprising first and second frustoconical portions  265   a ,  265   b ,  365   a ,  365   b , as well as a cartridge  262 ,  362  having an outlet end  152  with a single externally chamfered surface  292 ,  392  adjacent a primary seat  294 ,  394 , alternative embodiments may include different geometrical configurations. 
     For example,  FIG. 4  depicts a partial cross-section of one alternative embodiment of a valve port  436  constructed in accordance with the principles of the present invention and including a housing  460  and a cartridge  462 . The housing  460  and cartridge  462  are adapted to be arranged in operation with a spring such as springs  264 ,  364  described above with reference to  FIGS. 2-3 . 
     The housing  460  includes a nose  465 , a nut portion  466 , and a body portion  468 . The housing  460  may also include a curtain portion similar to the curtain portions  270 ,  370  described above with reference to  FIGS. 2-3 . The nose  465  of the housing  460  generally includes a bead extending circumferentially around the outlet end  152  of the valve port  436 . The nose  465  may include a rubber bead, a steel bead, or a bead constructed of generally any material. The nose  465  may even include an o-ring attached to the nut portion  466  of the housing  460 . 
       FIG. 4  depicts only a conduit portion  462   a  of the cartridge  462 . The conduit portion  462   a  is generally cylindrical and defines an elongated central orifice  488  along the flow path  148 . Moreover, the conduit portion  462   a  carries the outlet end  152  of the valve port  436 . The outlet end  152  serves as a primary seat  494 , which is adapted to be sealingly engaged by the valve disc  128  to stop the flow of gas through the regulator valve  104 . The specific embodiment of the outlet end  152  of the cartridge  462  includes first and second externally chamfered surfaces  492   a ,  492   b  separated by a planar surface  492   c . The first externally chamfered surface  492   a  is disposed at an angle α relative to the planar surface  492   c . The second externally chamfered surface  492   b  is disposed at an angle β relative to the planar surface  492   c . In the disclosed embodiment, the angle α is greater than the angle β. However, in alternative embodiments, the angle α may be less than or equal to the angle β. 
       FIG. 5  depicts yet another embodiment of a valve port  536  constructed in accordance with the present invention. Similar to the valve ports  136 ,  236 ,  436  described above, the valve port  536  includes a housing  560  and a cartridge  562 . The housing  560  and cartridge  562  are adapted to be arranged in operation with a spring such as springs  264 ,  364  described above with reference to  FIGS. 2-3 . 
     The housing  560  includes a nose  565 , a nut portion  566 , and a body portion  568 . The housing  560  may also include a curtain portion similar to the curtain portions  270 ,  370  described above with reference to  FIGS. 2-3 . The nose  565  of the housing  560  generally includes a single frustoconical protrusion extending circumferentially around the outlet end  152  of the valve port  536 . 
       FIG. 5  depicts only a conduit portion  562   a  of the cartridge  562 . The conduit portion  562   a  is generally cylindrical and defines an elongated central orifice  588  along the flow path  148 . Moreover, the conduit portion  562   a  carries the outlet end  152  of the valve port  536 . The outlet end  152  serves as a primary seat  594 , which is adapted to be sealingly engaged by the valve disc  128  to stop the flow of gas through the regulator valve  104 . The specific embodiment of the outlet end  152  of the cartridge  562  includes an externally chamfered surface  592   a  and a planar surface  592   b . The externally chamfered surface  592   a  is disposed at an angle α relative to the planar surface  592   b . Additionally, as depicted in  FIG. 5 , the valve port  536  may include a pneumatic seal such as an o-ring  583  disposed between the cartridge  562  and the housing  560 . However, as described above with reference to the valve port  136  described with reference to  FIGS. 2 ,  2 A, and  2 B, such a pneumatic seal is no required to seal a leakage path when the valve port  536  provides a secondary seal with a valve disc  128  because the valve disc  128  actually seals against the nose  565  of the housing  560  upstream of the cartridge  562 . 
     Therefore, regardless of the specific geometry of the various components of the valve ports  136 ,  236 ,  436 , and  536  depicted in  FIGS. 2-5 , the valve ports  136 ,  236 ,  436 , and  536  function in a substantially similar manner to advantageously provide a primary seal at an outlet end  152  of the valve ports  136 ,  236 ,  436 , and  536  and a secondary seal against a nose  165 ,  265 ,  465 , and  565  of the respective housings  260 ,  360 ,  460 , and  560 . At least one advantage of this configuration includes a more compact housing dimensions from the top of the noses  265 ,  364 ,  465 ,  565  to the bottom of the curtain portions  270 ,  370 ,  470 , and  570 , relative to the conventional valve port  36  described above with reference to  FIGS. 1 and 1A . This reduced dimension helps reduce material, weight, packaging, and cost of the overall valve port  136 ,  236 ,  436 ,  536 . 
     Moreover, the regulator  100  described herein is merely one example of a fluid control device incorporating the principles of the present invention. Other fluid control devices such as control valves may also benefit from the structures and/or advantages of the present invention.