Abstract:
A flow control valve for use in oxygen systems. The flow control valve has a body within an inlet and an outlet. A seat is located within the body and a ball retainer is located within the body. The ball retainer is able to capture a ball. The flow control valve also has biasing means connected to the ball retainer. Furthermore, the biasing means is movable between a flow and a non-flow position. The ball retainer is in a closed position when the ball, captured by the ball retainer, engages the seat to prevent gas flowing through the seat.

Description:
FIELD OF THE INVENTION 
     THIS INVENTION relates to a flow control valve. In particular, the invention relates to a flow control valve for use in oxygen-enriched environments and will therefore be described in this context. Oxygen-enriched environments include, but are not limited to, systems using low and high-pressure pure oxygen, high-pressure air and oxygen/nitrogen mixes with higher oxygen concentrations than standard temperature and pressure breathing air. However, it will be appreciated that the flow control valve may be used for other applications. 
     BACKGROUND OF THE INVENTION 
     Oxygen and high-pressure air valves are used in many applications including oxygen tanks, SCUBA systems, filling stations, space capsules, in-home liquid oxygen tank systems, fuel pipe oxygen systems, aeroplane pilots&#39; breathing apparatus, hospital breathing apparatus, steel, chemical and cold gasification plants, oxygen powered engines or any other associated processes. If oxygen is not properly controlled or used with equipment not specifically designed for oxygen, then accidents resulting in system failure and/or loss of plant, severe injury and death may occur. 
     Oxygen is an oxidising gas that vigorously supports burning. As a result, almost all materials are flammable and will burn actively at high temperatures in the presence of oxygen. Some materials which do not burn in air, will readily burn in oxygen-enriched atmospheres. In extreme cases, some materials may spontaneously burn in an oxygen-enriched environment if any heat generating mechanism is present and, if the concentration of this oxygen is sufficiently high, the burning of these materials may propagate to adjacent materials and devices. 
     Contaminants in oxygen systems are especially prone to ignite adjacent metallic and non-metallic materials and therefore greatly increase the potential for fire. When gas is compressed quickly inside a closed system such as a container or piping or a valve, the temperatures of the gas and adjacent materials can rise sharply. In an oxygen system, this rise in temperature can be high enough to cause ignition of contaminants such as oil, grease, solvents and materials such as dust, lint, metal chips, many organic and most non-metallic materials. Oxygen flowing at high speed through a valve or piping systems can also propel contaminants or particles with such force that friction or impact between the particles and/or system components can raise the temperature to ignition point of the contaminants, particles, or metallic system components, resulting in a major incident. It should also be appreciated that other ignition mechanisms are recognised to be present in these systems such as gas flow friction, mechanical friction, mechanical impact, electrical spikes and lightning strikes. 
     Ideally, cylinders, piping valves regulators, flame eaters and all other devices used in these systems will be constructed of non-flammable materials such as gold, silver (noble materials) and oxide ceramics. However, due to economic constraints and in order to achieve a non-leaking oxygen system, resilient sealing materials typically made of plastics, synthetic rubbers or some soft metals are often used. Unfortunately, these materials are less resistant to ignition than other metallic materials. Accordingly, materials with more favorable ignition and burning characteristics often result in leakages. 
     OBJECT OF THE INVENTION 
     It is an objection of the invention to overcome or alleviate one or more of the above disadvantages or provide the consumer with a useful commercial choice. 
     SUMMARY OF THE INVENTION 
     In one form, although not necessarily the only or broadest form, the invention resides in a flow control valve for use in oxygen systems, the flow control valve comprising: 
     a body having an inlet and an outlet; 
     a seat located within the body; 
     a ball retainer located within the body and able to capture a ball, 
     a biasing means connected to the ball retainer, the biasing means movable between a flow and a non-flow position; 
     wherein the ball retainer is in its closed position when the ball, captured by the ball retainer, engages the seat to prevent gas flowing through the seat. 
     A seat retainer may be used to hold the seat in a desired position. 
     Preferably at least the body, seat, ball retainer and biasing member are all made from a nickel based alloy or copper based alloy. Typically, brass is the copper based alloy. Preferably, UNS C38500 brass is used to manufacture at least the seat. 
     Preferably the threshold pressure of the materials that the body, seat, ball retainer and spring retainer are made of is greater than 25 MPA. More preferably, the threshold pressure of the materials is greater than 40 MPA. The threshold pressure is defined in ASTM (American Society for Testing and Materials) G 124 Standard Test Method for “Determining the Combustion Behaviour of Metallic Materials in Oxygen-Enriched Atmospheres”. 
     Preferably the ball is made from corundum. 
     The ball is typically made from aluminium oxide such as a ceramic or synthetic sapphire. However, it is envisaged that other metallics, oxides or other hard materials may be used and may be produced through various other process. 
     Preferably the hardness of the ball is preferably above 7 on Mohs hardness scale. More preferably, the hardness of the ball is preferably above 8 on Mohs hardness scale. Most preferably, the hardness of the ball is preferably above 9 on Mohs hardness scale. 
     Preferably, the surface finish is better than AFBMA (Anti-Friction Bearing Manufacturers Association) Grade 200. More preferably, the surface finish is better than AFBMA Grade 100. Most preferably, the surface finish is better than AFBMA Grade 50. 
     The biasing means is typically a spring. Normally the spring is a helical spring. Preferably the spring is made from wire that has a gauge of less than 3 millimeters. More preferably the spring is made from wire that has a gauge of less than 2 millimeters. Most preferably, the spring is made from wire that has a gauge of less than 1 millimeters. The spring may be fully compressed when the valve is opened. 
     Preferably, the spring prevents the ball retainer from moving more than 3 millimeters. More preferably, the spring prevents the ball retainer from moving more than 1 millimeters. Most preferably, the spring prevents the ball retainer from moving more than 0.5 millimeters. 
     A spring retainer may be used to hold and/or guide the spring within the body. 
     A lock device may be used to hold the spring retainer in a desired position within the body. 
     A filter may be located within the body. The filter may be located adjacent the seat. 
     An internal passageway of the body may by threaded. Accordingly, the seat retainer, spring retainer and lock device may all be also threaded. Engagement of the threads between the internal passageway of the body and the external threads of the seat retainer, spring retainer and lock device may be used to locate the seat retainer, spring retainer and lock device in their desired locations. 
     Preferably, the valve has a cracking pressure of less than 50 psi. More preferably, the valve has a cracking pressure of less than 40 psi. Most preferably, the valve has a cracking pressure of less than 30 psi. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the invention will be described with reference to the accompanying drawings in which: 
         FIG. 1  shows a side sectional view of a flow control valve according to the embodiment of the invention. 
         FIG. 2  shows a perspective view of a flow control valve body; 
         FIG. 3  shows a perspective view of a filter; 
         FIG. 3A  shows a further perspective view of the filter at  FIG. 3 ; 
         FIG. 4  shows a perspective view of a seat; 
         FIG. 4A  shows a further perspective view of the seat at  FIG. 4 ; 
         FIG. 5  shows a perspective view of a ball; 
         FIG. 6  shows a perspective view of a seat retainer; 
         FIG. 6A  shows a further perspective view of the seat retainer at  FIG. 6 ; 
         FIG. 7  shows a perspective view of a ball retainer; 
         FIG. 7A  shows a further perspective view of the ball retainer at  FIG. 7 ; 
         FIG. 8  shows a perspective view of a spring; 
         FIG. 9  shows a perspective view of a spring retainer; 
         FIG. 10  shows a perspective view of a lock device; 
         FIG. 11  shows a perspective view of a dust cap; 
         FIG. 12  shows a perspective view of a dust cap plug; 
         FIG. 13  shows a perspective view of a housing; 
         FIG. 14  shows a perspective view of the flow control valve of  FIG. 1 . and 
         FIG. 15  shows an exploded perspective view of the flow control valve of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIGS. 1 ,  14  and  15  shows a flow control valve  10  for use in a high pressure oxygen system. In particular, the flow control valve  10  shown in  FIGS. 1 ,  14  and  15  is for use with aircraft so that oxygen cylinders that are carried within the aircraft can be filled quickly, easily and safely. The flow control valve  10  includes a valve body  20 , filter  30 , seat  40 , ball  50 , seat retainer  60 , ball retainer  70 , spring  80 , spring retainer  90 , lock device  100 , dust cap  110 , dust cap plug  120  and housing  130 . 
     The valve body  20 , shown in  FIG. 2 , has a central passageway  21  that allows oxygen to flow from an inlet  22  to an outlet  23  through the valve body  20 . An inlet stem  24  is located adjacent the inlet  22  whilst an outlet stem  25  is located adjacent the outlet  23 . A hexagonal head  26  separates the inlet stem  24  from the outlet stem  25 . Both the inlet stem  24  and outlet stem  25  have an external thread. The outlet stem  25  also has an internal thread that extends along the passageway  23 . A lip  27  and a support  28  are located within the passageway  23 . 
     The filter  30  is shown in more detail in  FIG. 3  and  FIG. 3A . The filter  30  is made from sintered bronze and has a conical section  31  having a depending skirt  32 . The filter  30  filters any impurities located within the oxygen that flows through the passageway  23 . 
     The seat  40  shown in  FIG. 4  and  FIG. 4A  is made from brass and is substantially cylindrical in shape. A hole  41  extends through the seat  40  with a face  42  of the hole  41  being substantially perpendicular with the front face  43  of the seat  40 . A groove  44  is located on one side of the seat  40  to ensure the correct placement of the seat  40  within the valve body  20 . 
       FIG. 5  shows a ball  50  that is made from an alumina (aluminium oxide) that is formed into a synthetic sapphire (corundum). The surface finish of the ball  50  is very high and has a AFBMA grade of better than 100 (typically better than 25) with the hardness being 9 in Mohs hardness scale. It should be appreciated that the hardness necessary for the ball  50  is above 7 in the Mohs hardness scale and have a surface finish above AFBMA grade 200. 
       FIG. 6  shows a seat retainer  60  formed from Monel™. The seat retainer  60  is cylindrical in shape and has an external thread located around the edge of the seat retainer  60 . The seat retainer is hollow and has a hexagonal recess  61  located in the top of the seat retainer  60 . 
       FIG. 7  and  FIG. 7A  shows a ball retainer  70  made from Monel™. The ball retainer  70  includes a head  71  having a rearwardly extending boss  72 . A semi-spherical cup  73  is located within the head and has a diameter commensurate with respect to the ball  50 . Three flutes  74  extend longitudinally through the head  71  and boss  72 . It should be appreciated that the number of flutes  74  may be varied in accordance with oxygen flow requirements. 
       FIG. 8  shows the spring  80  in further detail. The spring  80  is a helical spring and is made from Nickel 200™. The wire that is used to produce the spring has a gauge of 0.8 millimeters. The spring  80  can be tensioned as desired depending on the required break pressure or cracking pressure. The most desirable cracking pressure is between 20 to 30 psi. 
       FIG. 9  shows a spring retainer  90  made from Monel™. The spring retainer  90  is cylindrical in shape and has an external thread. The spring retainer  90  also includes an outwardly extending boss  91 . A square aperture  92  extends through the spring retainer  90 . 
       FIG. 10  shows a lock device  190  that again is made from Monel™. The lock device is cylindrical in shape and has an external thread. A square aperture  101  extends through the lock device. 
       FIGS. 11 and 12  show a dust cap  110  and a dust cap plug  120  respectively. The dust cap plug  120  fits within the dust cap  110 . The dust cap  110  includes an internal thread  111  so that the dust cap  110  can be screwed on to the inlet stem  24  This causes the dust cap plug  120  to cover the inlet  24 . It should appreciated that the dust cap  110  and dust cap plug  120  can be of varying configurations and are not essential to the operation of the valve  10 . 
       FIG. 13  shows a housing  130  made from brass. The housing includes a housing member  131  having a depending flange  132 . An internal thread extends within the housing member  131 . A bore  133  extends through the housing body to allow oxygen that passes from the outlet  23  to flow to an accompanying device such as an oxygen storage cylinder (not shown). It should be appreciated that the housing  130  is not essential to the operation of the valve  10 , especially when the valve  10  is to be used in and in line high pressure oxygen system. 
     In order to assemble the flow control valve  10 , the filter  30  is dropped into the passageway  21  via the outlet  23 . The filter  30  sits within the passageway  21  so that the depending skirt abuts the lip  27  within the passageway  21 . The seat  40  is then dropped into the passageway  21  via the outlet  23  ensuring that the groove  44  located on the front face  43  of the seat  40  faces upwardly. The seat  40  sits on the support  28  located within the passageway  21 . The seat retainer  60  is then screwed into the passageway  21  with the external thread of the seat retainer  60  engaging the internal thread of the outlet stem  25 . A standard tool, such as an Allan key, is placed within the hexagonal recess to screw the seat retainer  60  into the passageway  21 . 
     The next step in assembly of the flow control valve  60  is to locate the boss  74  of the ball retainer  70  with the helical spring. The ball  50  is then placed within the semi-spherical cup. The ball  50 , ball retainer  70  and spring  80  are then placed into the passageway  21  until the ball  50  abuts against the hole  41  located within the seat  40 . 
     A spring retainer  90  is then placed within the passageway  21  and screwed into the passageway via its external thread mating within the internal thread of the outlet stem  23 . The square aperture  92  of the spring retainer  90  is used for placement of a specialized square tool. The spring retainer is screwed to a desired tension based on a required cracking pressure of the flow control valve  10 . Further, the spring retainer is screwed until the spring  80  is compressed to just before its maximum compression so that the ball  50  and the ball retainer  70  is only able to move approximately 0.5 millimeters during opening and closing of the valve  10 . The boss  91 , located on the spring retainer  90 , locates within the spring  80 . A lock device  100  is then screwed into the passageway  21  via the external thread of the lock device mating with the internal thread of the outlet stem  25 . The lock device  100  is screwed within the passageway  21  until it contacts the spring retainer  90  to hold the spring retainer  90  in a desired location. 
     The outlet stem  25  of the body  20  is then screwed into the housing  130  via the internal thread of the housing  130 . The body  20  is screwed into the housing  130  until the hexagonal head  26  abuts against the housing  130  to ensure the sealing of the body  20  with respect to the housing  130 . A dust cap  120  is then screwed on to the inlet stem via the threads of both the dust cap and the inlet stem, until the dust cap lug  120  covers the inlet  22 . 
     In use, the dust cap  110  and dust cap plug  120  are removed from the inlet stem  24 . An oxygen supply (not shown) is then connected to the inlet stem  24  and oxygen is fed through from the inlet  22  into the passageway  21 . High pressure oxygen passes through the filter  30  until there is sufficient pressure to force the ball  50  and ball retainer  70  against the spring  80  toward the outlet  23 . During opening of the valve, the spring  80  is full compressed to allow oxygen to pass through the hole  41  in the seat  40  and through the flutes  74  located within the ball retainer  70 . Oxygen is then able to pass through the spring retainer  130  and lock device  100  through the outlet  23  and through the respective bore in the housing  130 . 
     The above valve provides a valve that can operate with low or zero leak rates for an extended period of service in an oxygen system. Further, as the there are no “soft” seals (non-metallics) located within the valve and the elements of the valve will not support burning in their use environment, the likelihood of the valve igniting or burning is extremely low. Further, its ability to ignite adjacent components or materials or surroundings is extremely low providing an additional level of safety. 
     The valve provides a safe alternative to currently available products whilst offering improved functionality and performance in many situations. The principle of the valve&#39;s operation can be applied to various different checking devices for use in oxygen-enriched atmospheres such as, but not limited to, in line flow control valves, pressure relief valves, flame arrestors, manifold flow control valves, excess flow control valves and ball valves. 
     It should be appreciated that various other changes and/or modification can be made to the embodiment described without departing from the spirit or scope of the invention.