Abstract:
A regulator, valve and regulator system for regulation of pressure and flow of gas from a source to the environment, such as from a highly pressurized oxygen source in an emergency life support system to the surrounding environment. The regulator includes redundant flow paths and redundant stages for reliable control of gas pressure from the source. The valve includes a unique valve seat assembly and a bonnet assembly sealed both from the environment and from the gas flowing through the valve for control of flow of gas from the source.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/671,276 filed Jul. 13, 2012, which is hereby incorporated herein by reference. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates to an apparatus for regulation of pressure and flow of gas from a source to the environment, and particularly to a regulator having redundant flow paths and redundant stages for reliable control of gas pressure from a source, and also to a valve having a unique valve seat assembly and a bonnet assembly sealed both from the environment and from the gas flowing through the valve for control of flow of gas from a source. 
       BACKGROUND 
       [0003]    Flow systems for delivering pressure and flow from a source often encounter problems such as blockages, leakage, pressure fluctuations, and component failure. Current systems are often critical systems and are not made to deal with most or all of these problems. 
         [0004]    For example, lifesaving systems help mitigate the risks associated with mining operations. These systems take the form of enclosures with breathing oxygen available in the event the local atmosphere becomes contaminated. The oxygen delivery systems use highly pressurized oxygen, typically greater than 4500 psi, to store enough oxygen to sustain a large crew of miners for up to 4 days. 
         [0005]    In the event of an emergency, the system provides a continuous flow of oxygen. Existing systems have experienced problems that can affect the performance primary functions. For example, ice blockage or debris in the flow path can lead to flow issues. Moreover, because the systems are only active during emergencies, operator maintenance or even intervention may be impossible during use. 
         [0006]    It would be preferable if such systems were less likely to experience problems, particularly during emergencies. 
       SUMMARY OF THE INVENTION 
       [0007]    There is provided a gas supply system for delivering a continuous stream of gas from a source, the gas supply system including a regulator/regulator system and valve. According to one aspect of the invention, the regulator/regulator system may have primary and secondary redundant flow paths machined within the same regulator body such that there are no additional fittings or leak paths. According to another aspect of the invention, a second stage regulator, also plumbed with primary and secondary flow paths, may be included. The second regulator may be capable of maintaining a safe delivery pressure if a first regulator fails in a full open condition. According to a further aspect of the invention, the valve includes a valve keeper for retaining a valve seat and which minimizes direct impact of the high velocity flow on the valve seat material, as is preferred for sealing the valve. According to another aspect of the invention, valve materials coming in contact with the oxygen or air flow stream are materials known to minimize the risk of fire associated with oxygen. Materials exposed to the external environment are resistant to corrosive atmospheres. According to still another aspect of the invention, a sealed bonnet system of the valve protects internal components from the external environment and from high velocity flow through the valve. According to yet another aspect of the invention, the risk of fire is further reduced by isolating the valve stem threads and eliminating springs from the oxygen or air flow stream. 
         [0008]    Accordingly, there is provided a gas supply assembly for controlling a flow and regulating a pressure of gas from a source. The assembly comprises a valve for controlling the flow of gas from at least one gas vessel. The valve comprises a body having an inlet passage and an outlet passage, wherein the inlet passage is in fluidic communication with a valve chamber; a valve piston associated with the valve chamber and receiving a valve keeper and a valve seat, wherein the valve keeper is positioned in the path of the flow into the valve chamber and is impacted upon by the flow; and a bonnet assembly for engaging with the valve piston and isolating at least part of at least one component from flow through the body and from the environment, wherein the bonnet assembly is adapted to move the valve piston within the valve chamber causing the valve seat to engage or disengage the sidewall. The assembly also includes a regulator for regulating the pressure of a gas from the at least one gas vessel, connected downstream of the valve. The regulator comprises a housing; a primary flow path and a secondary flow path within the housing, the primary flow path providing for flow from the inlet to the outlet through a primary chamber, and the secondary flow path providing for flow from the inlet to the outlet through a secondary chamber; a connecting passage providing fluidic communication between the primary chamber, the secondary chamber, and the outlet; a primary valve system housed within the primary chamber for opening and closing the primary flow path; a secondary valve system housed within the secondary chamber for opening and closing the secondary flow path; a primary biasing element housed within the primary chamber and engaging the primary valve system; and a secondary biasing element housed within the secondary chamber and engaging the secondary valve system. Each of the biasing elements is adapted to bias the respective valve system in an open position allowing flow from the inlet to the outlet, and is also adapted to close the respective valve system when exposed to a pressure at the outlet sufficient to create a force equal to or greater than a biasing force of the respective biasing element. 
         [0009]    The primary biasing element and the secondary biasing element may be adjusted to different biasing forces and/or the primary biasing element may be adjusted to a primary biasing force greater than a secondary biasing force of the secondary biasing element. 
         [0010]    The primary biasing element and the secondary biasing element may be adjusted such that when gas flows in the inlet and out the outlet, the primary biasing force of the primary biasing element overcomes the pressure resulting from flow from the inlet and pressure at the outlet such that the primary valve system is open, and the pressure resulting from flow from the inlet and pressure at the outlet overcome the secondary biasing force of the secondary biasing element closing the secondary valve system. 
         [0011]    A restriction of the primary flow path may cause a decrease of the pressure resulting from flow from the outlet, thereby causing the secondary biasing force of the secondary biasing element to overcome the pressure resulting from flow from the outlet opening the secondary valve system. In a preferred arrangement, no operator intervention is required to open the secondary valve system. 
         [0012]    The primary valve system may comprise a primary valve member centrally deposed to a primary valve seat and engaged with the primary biasing element such that an increase of the pressure resulting from flow to the primary chamber causes the primary valve member to move axially towards the primary valve seat, and a decrease of the pressure resulting from flow from the primary chamber causes the primary valve member to move axially away from the primary valve seat. 
         [0013]    The secondary valve system may comprise a secondary valve member centrally deposed to a secondary valve seat and engaged with the secondary biasing element such that an increase of the pressure resulting from flow to the secondary chamber causes the secondary valve member to move axially towards the secondary valve seat, and a decrease of the pressure resulting from flow from the secondary chamber causes the secondary valve member to move axially away from the secondary valve seat. 
         [0014]    The connecting passage may form part of at least one of the primary flow path or the secondary flow path. 
         [0015]    At least one of the primary valve seat or the secondary valve seat may comprise at least one of a nickel alloy or a polyimide-based plastic. 
         [0016]    The primary biasing element may be sealed off from flow through the primary flow path and from the environment by at least one primary sealing element. 
         [0017]    The at least one primary sealing element and/or secondary sealing element may comprise a fluoroelastomer, polytetrafluoroethylene, silicone, or fluoropolymer. 
         [0018]    The secondary biasing element may be sealed off from flow through the secondary flow path and from the environment by at least one secondary sealing element. 
         [0019]    A passageway may provide for fluidic communication between the inlet passage and the valve chamber and may have an opening, wherein the valve keeper has a diameter at least as great as a diameter of the opening. 
         [0020]    The valve keeper may be centrally deposed to the valve seat and/or may retain the valve seat in the valve piston. 
         [0021]    The valve piston may have a bore for receiving the valve keeper, the valve keeper may have a contact surface positioned in the path of the flow into the valve chamber, and/or the valve keeper may have an orifice extending through the valve keeper from the contact surface to the bore. 
         [0022]    At least one of the valve keeper ( 416 ) or the valve seat ( 418 ) may comprise at least one of a nickel alloy or a polyimide-based polymer. 
         [0023]    The at least one component may be isolated from flow through the body and from the environment by at least one sealing element. 
         [0024]    The at least one sealing element may comprise at least one of a fluoroelastomer, a polytetrafluoroethylene, a silicone, or a fluoropolymer. 
         [0025]    The at least one component comprises at least one of a stem extending through the bonnet assembly and engaged with the body and the valve piston; or the valve piston engaged with the stem. 
         [0026]    The at least one component may include threads. 
         [0027]    The bonnet assembly may comprise an upper bonnet cap engaged with the body; a stem extending through the upper bonnet cap and engaged with the valve piston; a lower bonnet portion configured to receive the valve piston and engaged with the upper bonnet cap and the body; and a connecting element outside the bonnet assembly connecting an operator member outside the bonnet assembly to the stem; wherein rotation of the operator member causes rotation of the stem, thereby causing the valve piston to move within the bonnet assembly, thereby causing the valve seat to engage or disengage the sidewall of the valve chamber. 
         [0028]    The valve piston may be comprised of a lower valve piston body for receiving the valve keeper and the valve seat and having the bore; and an upper driver body connected to a stem and engaged with the lower valve piston body, wherein the stem extends through the bonnet assembly and engages with the body. 
         [0029]    According to a further aspect of the invention, a regulator system for regulating the pressure of a gas from the at least one gas vessel, connected downstream of the valve, wherein the regulator system comprises a first regulator as above described and a second regulator connected in series with the first regulator, with an outlet of the first regulator in fluidic communication with an inlet of the second regulator. 
         [0030]    The invention also provides a method of using a regulator as herein described for controlling the pressure resulting from a gas flowing from a source, the method comprising the steps of adjusting at least one of the primary biasing element or the secondary biasing element such that the primary biasing element has a primary biasing force greater than a secondary biasing force of the secondary biasing element. 
         [0031]    According to still another aspect of the invention, a regulator for regulating the pressure of a gas from a source, comprises a housing; a primary flow path and a secondary flow path within the housing, the primary flow path providing for flow from an inlet to an outlet through a primary chamber, and the secondary flow path providing for flow from the inlet to the outlet through a secondary chamber; and a connecting passage providing fluidic communication between the primary chamber, the secondary chamber, and the outlet; a primary valve system housed within the primary chamber for opening and closing the primary flow path, and a secondary valve system housed within the secondary chamber for opening and closing the secondary flow path; a primary biasing element housed within the primary chamber and engaging the primary valve system, and a secondary biasing element housed within the secondary chamber and engaging the secondary valve system; wherein each of the biasing elements is adapted to bias the respective valve system in an open position allowing flow from the inlet to the outlet, and is also adapted to close the respective valve system when exposed to a pressure at the outlet sufficient to create a force equal to or greater than a biasing force of the respective biasing element. 
         [0032]    According to yet a further aspect of the invention, a valve for controlling a flow of a gas from a source comprises a body having an inlet passage and an outlet passage, wherein the inlet passage is in fluidic communication with a valve chamber; a valve piston associated with the valve chamber and receiving a valve keeper and a valve seat, wherein the valve seat cooperates with a sidewall of the valve chamber to seal off the flow to the valve chamber, and wherein the valve keeper is positioned in the path of the flow into the valve chamber and is impacted upon by the flow; and a bonnet assembly for engaging with the valve piston and isolating at least part of at least one component from flow through the body and from the environment, wherein the bonnet assembly is adapted to move the valve piston within the valve chamber causing the valve seat to engage or disengage the sidewall. 
         [0033]    The foregoing and other aspects and features of the invention are hereinafter described in reference to the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1  is a schematic diagram of a gas supply system; 
           [0035]      FIG. 2  is a cross-sectional view of a regulator of the gas supply system of  FIG. 1 ; 
           [0036]      FIG. 3  is a cross-sectional view of a regulator system of the gas supply system of  FIG. 1 ; and 
           [0037]      FIGS. 4 through 8  are perspective views of a valve of the gas supply system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0038]    Flow systems for delivering pressure and flow from a source are often critical systems relied upon for safety. For example, oxygen-delivering lifesaving systems are in place to provide emergency oxygen to a crew of miners in the case of an emergency. These lifesaving systems often take the form of enclosures providing breathing oxygen that is available in the event the local atmosphere becomes contaminated. 
         [0039]    The present invention relates to regulators or regulator systems for assisting with delivery of gases, and preferably to regulators and regulator systems having particular application for the delivery of oxygen to miners and the like in the case of an emergency. The regulator or regulator system provides for backup flow passages that enable a continuous supply of gas, in particular oxygen or air, if the pressure in the primary flow path drops. The secondary flow path may be engaged without operator intervention. The primary and secondary flow paths may be machined within the same regulator body, for example, to minimize fittings and leak paths. 
         [0040]    Additionally, a second stage regulator, also plumbed with primary and secondary flow paths, may be included. The second stage regulator may be capable of maintaining a safe delivery pressure even if a connected regulator fails in a full open condition. 
         [0041]    The present invention also relates to valves and a system for assisting with delivery of liquids, gases, or a combination thereof using valves. The valve may provide for reduced risk of fire associated with high pressure oxygen and air while providing resistance to corrosive environments, such as in mines, chemical plants, or marine environments. 
         [0042]    The portions of the valve coming in contact with the air flow stream, such as an oxygen stream, may be made of materials known to minimize the risk of fire associated with the respective air flow stream. 
         [0043]    The portion of the valve exposed to the external environment may be resistant to corrosive atmospheres. 
         [0044]    A sealed bonnet system protects internal components from the external environment and from high velocity flow through the valve. 
         [0045]    In addition, the valve stem threads may be isolated. 
         [0046]    Also, the valve may include a springless design. 
         [0047]    Additionally, a valve keeper may be included to minimize direct impact of the high velocity flow on the valve seat material. 
         [0048]    Turning first to  FIG. 1 , a schematic diagram of a system  100  for the delivery of gases to a device  101  for receiving, mixing, and/or delivering said gases to the environment is shown.  FIG. 1  represents an ideal system having a gas assembly  102   a  for delivering a first gas, such as air, and a gas assembly  102   b  for delivering another gas, such as oxygen. As shown, each assembly  102   x  (x is used to denote either a or b in the respective systems) may include a gas vessel  104   x  and a valve  400   x  connected in series downstream of the gas vessel  104   x  for controlling a flow of gas, as separately shown in  FIGS. 4  through  8 . The device may, for example, mix gases from different sources for supply to an enclosed environment, such as mine tunnel. 
         [0049]    It will be appreciated that “x” is used herein as a place holder to generally refer to any other specific component such as “a” or “b.” For example, assembly  102   x  may generally refer to either of assembly  102   a  or assembly  102   b.    
         [0050]    The valve  400   x  as shown is connected in the gas assembly  102   x  upstream of an outlet of the system  106   x.  Each assembly  102   x  may also include a regulator  200   x  or a regulator assembly  300   x  connected in series downstream of the gas vessel  104   x  for regulating the pressure of a gas, as separately shown in  FIGS. 2 and 3 , respectively, and also previously described. The regulator  200   x  or regulator system  300   x  is connected in the gas assembly  102   x  upstream of an outlet of the system  106   x.    
         [0051]    Additionally, each assembly  102   x  may include a filter  108   x  interposed in series between the valve  400   x  and the regulator  200   x  or the regulator system  300   x.    
         [0052]    Each assembly  102   x  may also include a filter  108   x  interposed in series between the regulator  200   x  or the regulator system  300   x  and the outlet of the system  106   x.    
         [0053]    The outlets  106   a  and  106   b  may be combined or may be separate. 
         [0054]    Turning next to  FIG. 2 , a cross-sectional view of a regulator, such as regulator  200   c  or  200   d,  for controlling the pressure resulting from the flow of gas from a source is illustrated. The regulator  200   x  has a single housing  250  with a single inlet  254  and a single outlet  256 . The housing  250  contains a primary flow path  252   a  and a secondary flow path  252   b.  The use of a single housing  250  for the primary flow path  252   a  and secondary flow path  252   b  may advantageously eliminate the T-fittings and connectors that would otherwise be present in such a system, thereby reducing the number of potential interfaces where leakage may occur. 
         [0055]    The primary flow path  252   a  and the secondary flow path  252   b  provide for flow from the inlet  254  to the outlet  256 . It will be understood by those of ordinary skill in the art that as gas initially flows into the inlet  254  of the regulator  200 , it will flow through both of the primary flow path  252   a  and the secondary flow path  252   b.    
         [0056]    Turning first to the primary flow path  252   a,  gas will flow past the primary valve system  262   a  for opening and closing the primary flow path  252   a.  The primary valve system  262   a  includes a primary valve seat  268   a  and a primary valve member  266   a.  The primary valve member  266   a  provides for a seal against the primary valve seat  268   a  and for closure of the primary flow path  252   a.    
         [0057]    Gas from the inlet  254  will thus initially flow past the primary valve seat  268   a  and into the primary chamber  258   a.  The gas will communicate with a primary biasing element  264   a  housed within the primary chamber  258   a.    
         [0058]    The primary biasing element  264   a  may be adjustable to a primary biasing force. 
         [0059]    The primary biasing element  264   a  may also be adapted to engage the primary valve system  262   a  and to provide for the opening and closing of the primary valve system  262   a  via compression and relaxation of the primary biasing element  264   a.  Particularly, movement of the primary valve member  266   a  towards the primary valve seat  268   a  may be provided by a compression of the primary biasing element  264   a  when exposed to a pressure of the gas flowing from the inlet  254 . Alternatively, movement of the primary valve member  266   a  away from the primary valve seat  268   b  may be provided by a relaxation of the primary biasing element  264   a  when exposed to a reduced pressure or no pressure due to reduced flow or no flow from the inlet  254 . 
         [0060]    A primary valve spring  267   a  may be present in the primary valve system  262   a  and may be engaged with the primary valve member  266   a.  The primary valve spring  267   a  may provide a force to the primary valve member  266   a  to maintain seal against the primary valve seat  268   a.  Specifically, this action may occur when the force resulting from pressure of the gas flowing from the inlet  254  overcomes the biasing force of the primary biasing element  264   a.  For example, the primary biasing element  264   a  may be adjusted to a predetermined primary biasing force that may be overcome by the force resulting from the gas flowing from the inlet  254 . 
         [0061]    The primary valve member  266   a  may be centrally deposed to the primary valve seat  268   a,  which may be annular in shape as shown or of any other suitable shape, in order to provide efficient sealing of the primary valve member  266   a  against the primary valve seat  268   a.    
         [0062]    The primary valve seat  268   a  may be made of a nickel alloy or a polyimide-based plastic, such as Monel or Vespel, or may be made of any other suitable material. 
         [0063]    The primary biasing element  264   a  may have multiple elements allowing it to compress and relax when acted upon by a pressure of gas flowing through the regulator. As shown, the multiple components of the primary biasing element  264   a  include a primary cap portion  280   a  engaging the housing  250 . A primary regulator piston  282   a  engages both the housing  250  and the primary cap portion  280   a.  A primary spring  284   a  is interposed between a primary first spring retainer  286   a  and a primary second spring retainer  288   a,  the spring retainers themselves floating interposed between the primary regulator piston  282   a  and the primary cap portion  280   a.    
         [0064]    The spring retainers may be floating by way of cylindrical or ball protrusions  290   a,  wherein at least one of the cylindrical or ball protrusions  290   a  is deposed on an end of a primary adjustment stem  292   a.  The protrusions  290   a  may also be of any other suitable shape. 
         [0065]    The primary adjustment stem  292   a  is preferably threaded through the primary cap portion  280   a,  wherein rotation of the primary adjustment stem  292   a  causes adjustment of the distance between the primary first spring retainer  286   a  and the primary second spring retainer  288   a,  thereby enabling adjustment of the primary biasing force of the primary biasing element  264   a.    
         [0066]    Further, the primary cap portion  280   a  may be threaded to the housing  250  or may be engaged with the housing  250  by a primary collar  294   a,  itself attached to the housing  250  via cooperating threading of the housing  250  and cap portion  280   a,  or via other suitable structure. 
         [0067]    Additionally, according to another aspect of the invention, the internal elements of the primary biasing element  264   a  are sealed off from flow through the primary flow path  252   a  and from the environment by at least one primary sealing element  270   a.    
         [0068]    The internal elements of the primary biasing element  264   a  may include, for example, the primary spring  284   a,  the primary first spring retainer  286   a,  the primary second spring retainer  288   a,  and the primary cylindrical or ball protrusions  290   a.  As shown, primary sealing elements  270   a  are disposed between the primary regulator piston  282   a  and the housing  250  and also between the primary regulator piston  282   a  and the primary cap portion  280   a . One or more of the sealing elements  270   a  may be made of a fluoroelastomer, a polytetrafluoroethylene, a silicone, or a fluoropolymer, such as Teflon or Viton, or may be made of any other suitable material. 
         [0069]    Accordingly, in use of the regulator  200   x,  gas will flow from the inlet  254 , past the spring  267   a  and valve seat  268   a  and into the primary valve chamber  258   a,  where it may act upon the primary biasing element  264   a.  Such action may overcome the predetermined biasing force of the biasing element  264   a , causing compression of the biasing element  264 , and allowing the primary valve member  266   a  to move towards the primary valve seat  268   a  via the spring  267   a . The primary valve system  262   a  will thereby be caused to fully close until the force resulting from pressure of the gas flowing from the inlet  254  is reduced to a level lower than the primary biasing force. 
         [0070]    In addition, opening of the primary valve system  262   a  via movement of the primary valve member  266   a  away from the primary valve seat  268   a  may be provided by a relaxation of the primary biasing element  264   a.  Specifically, this action may occur when the primary biasing element  264   a  is exposed to a decreasing force resulting from pressure of gas flowing from the primary chamber  258   a  to the outlet  256 . The primary biasing force of the primary biasing element  264   a  may thereby overcome the decreasing pressure within the primary chamber  258   a,  and may also thereby overcome the primary valve spring  267   a  allowing the primary valve member  266   a  to move away from the primary valve seat  268   a.  The primary valve system  262   a  may thereby be caused to reopen and again allow flow of gas from the inlet  254  into the primary chamber  258   a  until a force resulting from pressure of the gas flowing from the inlet  254  again overcomes the primary biasing force of the primary biasing element  264   a.  This sequence will continue allowing for regulation of the pressure of a gas flowing through the primary flow path  252   a  from the inlet  254  to the outlet  256 . 
         [0071]    Turning now to the secondary flow path  252   b,  the same sequence initially occurs whereby the pressure resulting from the flow of gas from the inlet  254  past a secondary valve system  262   b  and into a secondary chamber  258   b  causes a secondary biasing element  264   b  to close the secondary valve system  262   b.  As illustrated, the secondary biasing element  264   b,  which may be adjustable to a secondary biasing force, engages the secondary valve member  266   b  of the secondary valve system  262   b  causing it to move towards the secondary valve seat  268   b,  also of the secondary valve system  262   b,  as the secondary biasing element  264   b  compresses. 
         [0072]    The secondary valve member  266   b  and secondary valve seat  268   b  may be made of the same suitable materials as the primary valve member  266   a  and primary valve seat  268   a,  respectively, or may be made of other suitable material. 
         [0073]    As in the primary flow path  252   a,  a secondary valve spring  267   b  in the secondary flow path  252   b,  in association with the secondary valve system  262   b , may provide a force to the secondary valve member  266   b,  enabling it to maintain seal against the secondary valve seat  268   b.    
         [0074]    Similar to the primary biasing element  264   a,  the secondary biasing element  264   b,  may include a secondary cap portion  280   b,  a secondary collar  294   b,  a secondary regulator piston  282   b,  a secondary spring  284   b,  a secondary first spring retainer  286   b,  a secondary second spring retainer  288   b,  secondary cylindrical or ball protrusions  290   b,  and a secondary adjustment stem  292   b.    
         [0075]    Further, the internal elements of the secondary biasing element  264   b , respectively, are sealed off from flow through the secondary flow path  252   b  and from the environment by at least one secondary sealing element  270   b  made of the same or different suitable material as the primary sealing element  270   a.    
         [0076]    Like the primary biasing element  264   a,  the secondary biasing element  264   b  may have an adjustable biasing force. If the secondary biasing element  264   b  has a secondary biasing force equal to the primary biasing force of the primary biasing element  264   a,  gas will flow through both the primary flow path  252   a  and the secondary flow path  252   b.  Those with ordinary skill in the art will recognize that if the primary biasing element  264   a  has a primary biasing force greater than the secondary biasing force of the secondary biasing element  264   b , only flow through the primary flow path  252   a  will occur. Particularly, when used with a high pressure gas, when the biasing elements are adjusted for use with the high pressure gas, and when the primary biasing force is adjusted to be greater than the secondary biasing force, high pressure flow from the inlet  254  will cause the primary valve system  262   a  to cycle between open and closed states while maintaining closure of the secondary valve system  262   b.    
         [0077]    A connecting passage  260  provides fluidic communication, including communication of gases, liquid, or a combination thereof, between the primary chamber  258   a  and the secondary chamber  258   b.    
         [0078]    The connecting passage  260  may be part of one or both of the primary flow path  252   a  or the secondary flow path  252   b.    
         [0079]    In addition, the connecting passage  260  may provide an alternative path for fluidic communication between the primary chamber  258   a  and the secondary chamber  258   b  that is separate from one or both of the primary flow path  252   a  or the secondary flow path  252   b.    
         [0080]    As such, a pressure from the outlet  256  may cause a pressure within the primary chamber  258   a  to equalize with a pressure within the secondary chamber  258   b.  Such equalization will be controlled by the greater of the primary biasing force of the primary biasing element  264   a  or the secondary biasing force of the secondary biasing element  264   b.  In the case that the primary biasing force is greater than the secondary biasing force, the resulting pressure in the connecting passage  260 , from the outlet  256 , will overcome the secondary biasing force. The secondary biasing element  264   b  will be thereby caused to compress moving the secondary valve member  266   b  towards the secondary valve seat  268   b  and closing the secondary valve system  262   b.  The secondary valve system  262   b  and the secondary flow path  252   b  will remain closed until gas flow out of the regulator  200   x  through the outlet  256  results in a decrease in pressure in the secondary chamber  258   b.    
         [0081]    The presence of two flow paths, including the primary flow path  252   a  and the secondary flow path  252   b,  may be particularly advantageous if flow to the primary flow path  252   a  becomes blocked. Blockage may be caused, for example, by ice build-up caused by use in low temperature situations or by use with high pressure gases, the pressure drop between the inlet and the outlet having the effect of cooling the system to below the freezing temperature of liquids in the surrounding environment, such as water. 
         [0082]    The system may be configured, such as by making the primary biasing force greater than the secondary biasing force, so that no operator intervention is required to open the secondary valve system  262   b,  in the case of a blockage in the primary valve system  262   a.  Such partial or full blockage of the primary flow path  252   a  will result in an opening of the secondary flow path  252   b  from its normally closed position previously described. 
         [0083]    Particularly, a restriction of the primary flow path  252   a  will cause a reduction in flow from the primary chamber  258   a  and thus also cause less flow through the outlet  256 , thereby causing a reduction in pressure acting upon the secondary biasing element  264   b  within the secondary chamber  258   b  via the connection passage  260 . As a result, the secondary biasing force of the secondary biasing element  264   b  will overcome the pressure in the secondary chamber  258   b  causing the secondary biasing element  264   b  to relax. The secondary valve member  266   b  will be caused to move away from the secondary valve seat  268   b  opening the secondary flow path  252   b.  The regulator therefore provides backup flow passages that will enable a continuous supply of gas if the pressure of the primary flow path  252   a  drops due to a partial or complete blockage of the primary flow path  252   a.    
         [0084]    It will be understood by those of ordinary skill in the art that a method for using the regulator  200   x  may include adjusting at least one of the primary biasing element  264   a  or the secondary biasing element  264   b  such that the primary biasing element  264   a  has a biasing force greater than a biasing force of the secondary biasing element  264   b.    
         [0085]    Turning next to  FIG. 3 , a cross-sectional view of a regulator system  300   x  for controlling the pressure of resulting from a flow of gas from a source is illustrated. The regulator system as shown includes two regulators  200   c - d  as depicted in  FIG. 2  at  200   x , including any of the aspects previously recited. The two regulators  200   c - d  are connected in series, whereby the outlet  256   c  of the first regulator  200   c  is in fluidic communication with the inlet  254   d  of the second regulator  200   d  via a connection member  302 . Additionally, it will be understood by one of ordinary skill in the art that more than two regulators may be connected in the same manner. 
         [0086]    The regulator system  300   x  provides for backup regulation that enables a continuous regulated supply of gas if any regulator fails in the open position, whereby each biasing element  264   a - b  (see  FIG. 2 ) causes each valve system  262   a - b  (see  FIG. 2 ) to remain open. The result is that combined with the redundancy of multiple flow paths, the regulator system  300   x  can function when there is either a blocked flow path or a complete failure of at least one regulator  200   x  of the regulator system  300   x.    
         [0087]    In use, at least two regulators  200   x  as depicted in  FIG. 2 , and including any of the aspect previously recited, may be connected in series, such as via a connection member  302 , whereby the outlet  256   c  of the first regulator  200   c  coming into contact with a gas from a source is in fluidic communication with the inlet  254   d  of the second regulator  200   d  subsequently coming into contact with the gas from a source. Additionally, the primary biasing element  264   a  and the secondary biasing element  264   b  of each regulator  200   x  may be adjusted, whereby for each regulator  200   x,  the respective primary biasing element  264   a  is adjusted to a primary biasing force that is greater than the secondary biasing force of the respective secondary biasing element  264   b.    
         [0088]    Turning next to  FIGS. 4 through 8 , a valve, such as valve  400   x,  for controlling a flow of a gas from a source is illustrated. The valve  400   x  has a body  401 , which has an inlet passage  402  and an outlet passage  404 . The inlet passage  402  is in fluidic communication with a valve chamber  408 , such as via a passageway  406 . 
         [0089]    A valve piston  426  within the valve chamber  408  may be adapted to receive both a valve keeper  416  and a valve seat  418  into a bore  414  of the valve piston  426 . The valve seat  418  communicates with a sidewall  420  of the body  401 , enabling shut off and control of flow from the inlet passage  402  to the outlet passage  404 . For example, the valve seat  418  may engage and disengage the sidewall  420 . As shown, the valve seat  418  may be annular in shape, although it may be of any other suitable shape, and may be carried by the valve keeper  416  centrally deposed to the valve seat  418 . 
         [0090]    The valve keeper  416  may have an orifice  432  that extends through the valve keeper  416  from a contact surface  422  of the valve keeper  416 , in direct contact with the flow of gas from the inlet passage  402 , to the bore  414 . The orifice  432  may permit gas or air to escape the bore  414  upon insertion of the valve keeper  416  into the bore  414  during manufacturing. The orifice  432  therefore reduces a risk that air trapped in the bore  414  will expand when heated, causing the valve keeper  416  to move away from the valve piston  426 . 
         [0091]    The  400   x  valve may be configured such that the valve keeper  416 , and not the valve seat  418 , is positioned in the path of the flow into the valve chamber  408  and is the initial impact point for the flow. Direct impingement of the flow velocity and high velocity particles on the valve seat  418  may thus be minimized. 
         [0092]    When such a valve  400   x  is used in a critical flow system, such as a lifesaving system for delivering oxygen, the risk of gas-related fire, such as oxygen-related fire, may be reduced. 
         [0093]    In addition, the valve keeper  416  may have a diameter at least as great as a diameter of an opening  410  of the passageway  406  into the valve chamber  408 , which may further reduce the risk of gas-related fire. 
         [0094]    In this arrangement, the valve seat  418  may be made from a non-metal such that it provides for a more efficient seal with the body  401 , and the valve keeper  416  may be made from a metal such that it is more durable, though they may also be made from any other suitable material. 
         [0095]    For example, the valve keeper  416  may be made from a nickel alloy such as Monel, and the valve seat  418  may be made from a polyimide-based polymer such as Vespel. 
         [0096]    Additionally, both the valve keeper  416  and the valve seat  418  may be wetted by the flow through the valve and may be made from materials known to reduce the risk of fire associated with gases used with the valve  400   x,  such as oxygen in the case of a lifesaving system. 
         [0097]    According to another aspect of the invention, a bonnet assembly  424  is partially retained in the valve chamber  408 . The bonnet assembly  424  provides for engagement with the valve piston  426  and is adapted to move the valve piston  426  within the valve chamber  408 . This movement causes the valve seat  418  to engage or disengage the sidewall  420  of the body  401 , opening or closing the valve  400   x,  and controlling a flow of gas from the inlet passage  402  to the outlet passage  404 . 
         [0098]    Additionally, the bonnet assembly  224  may provide for isolation of at least part of an isolated component from flow through the body  401  via at least one sealing element  428 . 
         [0099]    The at least one sealing element  428  may be made of a fluoroelastomer, a polytetrafluoroethylene, a silicone, or a fluoropolymer, such as Teflon or Viton, or of any other suitable material, and may isolate at least part of a an isolated component from a possibly corrosive external environment. 
         [0100]    The at least one isolated component may include a stem  452  extending through the bonnet assembly  424  and engaged with both the body  401  and the valve piston  426 , or it may include the valve piston  426  engaged with the stem  452 . 
         [0101]    Particularly, the isolated component may include wear parts, e.g., threads, springs, and other aspects of the bonnet assembly  424  that may generate particles and heat due to friction with gas flow. In this manner, the wear parts such as threads  430  of the stem  452 , for engaging with threads  431  of the valve piston  426 , may be isolated. 
         [0102]    Particles generated in other cylinder valves due to wear parts may result in fire in downstream system features due to high velocity impact. 
         [0103]    In the valve  400   x,  for use in a critical flow system, such as a lifesaving system, isolating wear parts may instead reduce the risk of fire. Further, by isolating parts of or whole wear parts, internal features or parts of the bonnet assembly  424  may be made of cheaper materials, while external parts of the bonnet assembly may be made of materials more resistant to corrosive atmospheres or high velocity flow of gases through the valve  400   x.    
         [0104]    The valve piston  426 , one of the isolated components, may include multiple connected elements. As shown, the valve piston  426  includes a lower valve piston body  412 , e.g. a poppet, for receiving the valve keeper  416  and the valve seat  418  and having the bore  414 . The valve piston  426  may also include an upper driver body  454  connected to the stem  452  via the threads  430  and  431  and engaged with the lower valve piston body  412 . Therefore, as shown, part of the lower valve piston body  412  and the entirety of the upper driver body  454  are isolated from the external environment and flow through the body  401 . 
         [0105]    The bonnet assembly  424  includes several bonnet components. An upper bonnet cap  450  is engaged with the body  401 . The stem  452 , also a component of the bonnet assembly  424 , extends through the upper bonnet cap  450  and engages with the valve piston  426 . 
         [0106]    In addition, the bonnet assembly  424  may include a lower bonnet portion  456  configured to receive the valve piston  426  and engaged with the upper bonnet cap  450  and the body  401 . 
         [0107]    The lower bonnet portion  456  may be connected, such as by threads, to the lower valve piston body  412  of the valve piston  426 . 
         [0108]    The bonnet assembly  424  may also include sealing elements  468 , such as gaskets, bearings, washers, or other suitable elements, to separate the stem  452  from and cushion the stem  452  against other bonnet components, such as the upper bonnet cap  450  and the lower bonnet portion  456 . 
         [0109]    Additional sealing elements  468  may be disposed between the upper bonnet cap  450  and the stem  452 , between the upper bonnet cap  450  and the body  401 , and between the lower bonnet portion  456  and the body  401 . Sealing elements  468  may also be disposed between the lower bonnet portion  456  and the valve piston  426 , or more specifically between the lower bonnet portion  456  and both the lower valve piston body  412  and the upper driver body  454  of the valve piston  426 . 
         [0110]    A safety plug  462  may be received in a secondary passageway  464 , providing a possible path of relief for gas flow prior to entrance into the valve chamber  408 , thereby providing a path for release of gas from the valve  400   x  in the case of a possible increase in the pressure of gas entering the inlet passage  402 . 
         [0111]    The valve  400   x  may also include an external leak test port  466  in the upper bonnet cap  450  and an internal leak test port  470  in the lower bonnet portion  456  to provide paths for trapped gas, such as air. Such paths may allow the trapped gas to escape in the case of gas expansion due to application involving or causing high temperatures of the valve  400   x.    
         [0112]    A connecting element  458 , such as a screw, disposed at least partially outside the bonnet assembly  424  connects an operator member  460 , such as a handle, also outside the bonnet assembly  424 , to the stem  452 . As shown, rotation of the operator member  460  causes rotation of the stem  452 , thereby causing the valve piston  426  to move within the bonnet assembly  424 , which in turn causes the valve seat  418  to engage or disengage the sidewall  420  of the valve chamber  408 . More specifically, rotation of the stem  452  causes the upper driver body  454  to move axially, thereby causing the lower valve piston body  412  to move axially. Accordingly, one of ordinary skill will realize that the bonnet assembly may include an anti-rotation feature, not specifically shown. 
         [0113]    Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the drawings. In particular, in regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent). In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application. The use of “comprising” or “comprise” herein is intended to include the recited components without exclusion of other components.