Abstract:
A valve assembly ( 10 ) able to be mounted with a liquid container, the valve assembly comprising: a housing ( 20 ) having a passageway ( 60 ) that extends through the housing; a breather float valve ( 80 ) mounted within the housing, the breather float valve movable between an open position to allow gas to pass through the passageway and a closed position that prevents liquid from passing through the passageway; a liquid inlet ( 30 ), forming part of the housing, the liquid inlet allowing fluid to pass into the housing; and an inlet float valve ( 41 ) mounted within the housing, the inlet float valve movable between an open position that permits the flow of liquid through the liquid inlet and a closed position that prevents the flow of fluid through the liquid inlet.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to a valve assembly. In particular, the invention relates to a valve assembly used to protect fuel tanks from being overfilled with fuel and therefore the invention will be described in this context. However, it is envisaged that the valve assembly may be used to protect the other types of containers from being overfilled with other types of fluid. 
       BACKGROUND OF THE INVENTION 
       [0002]    For many years large machinery fitted with fuel tanks have been equipped with fast fill systems to enable rapid filing of large capacity fuel tanks. The existing fast fill fuel systems rely on an air vent that prevents air from escaping the fuel tank when the required level of fuel has been attained. This causes pressure in the fuel tank to increase to a level that automatic shuts-off a fuel supply nozzle. 
         [0003]    A major concern of this system is that when the fuel level activates the shut-off for the fuel supply nozzle, the shut-off can be overridden and fuel can continue to be forced into the fuel tank above the normal level. This can cause the fuel tank to rupture from the high pressure attained when filling. 
         [0004]    U.S. Pat. No. 6,311,723, (by the applicant), has addressed this problem by devising a flow control valve assembly that prevents the build up of pressure within the fuel tank during and after filing. The flow control valve assembly also prevents the supply fuel nozzle from being overridden thus preventing the possibility of overfilling. U.S. Pat. No. 6,311,723 is hereby incorporated by reference. 
         [0005]    The control valve assembly of U.S. Pat. No. 6,311,723 uses float valve to determine when the level of fuel in the fuel tank is at a desired level. When the desired level of fuel has been attained, the float valve is used to block the flow of fuel through a bleed pipe to stop the flow of fuel through a control valve. An open breather is provided within the fuel tank to allow gas to escape from the fuel tank during filling to prevent the fuel tank rupturing. 
         [0006]    The flow control valve assembly operates very effectively on machinery that is predominately stationary. However, when the control valve assembly is mounted to vehicles&#39; fuel tanks, such as those located in trucks and excavators, some difficulties may experienced during movement of the vehicle. 
         [0007]    One problem that may be experience is that the float valve may become broken. The float valve comprises a float that is mounted on a pivotally movable elongate arm. This arm can break due to the large forces that are exerted on the arm by the surging fuel caused by movement of the vehicle. 
         [0008]    In the event that the control valve assembly fails, in this or any other manner, the fuel supply nozzle will continue to fill the tank and pass fuel through the open breather until the nozzle is shut-off manually. This may lead to many hundreds or even thousands of litres of fuel being wasted and the spilt fuel being disposed. 
         [0009]    Another problem that occurs is fuel is passed through the open breather during movement of the vehicle. Fuel surges cause fuel to flow through the open breather and escape the fuel tank. Again, this wastes fuel and is environmentally unfriendly. Further, the spilt fuel also creates a fire vehicle hazard. 
       OBJECT OF THE INVENTION 
       [0010]    It is an object of the invention to overcome or alleviate one or more of the above disadvantages or to provide the consumer with a useful or commercial choice. 
       SUMMARY OF THE INVENTION 
       [0011]    In one form, although not necessarily the only or broadest form, the invention resides in a valve assembly able to be mounted with a liquid container, the valve assembly comprising: 
         [0012]    a housing having a passageway that extends through the housing; 
         [0013]    a breather float valve mounted within the housing, the breather float valve movable between an open position to allow gas to pass through the passageway and a closed position that prevents liquid from passing through the passageway; 
         [0014]    an liquid inlet, forming part of the housing, the liquid inlet allowing fluid to pass into the housing; and 
         [0015]    an inlet float valve mounted within the housing, the inlet float valve movable between an open position that permits the flow of liquid through the liquid inlet and a closed position that prevents the flow of fluid through the liquid inlet. 
         [0016]    Preferably, the valve assembly also includes a relief valve that is movable between an open position and a closed position to allow pressure to be relieved from the container. 
         [0017]    Preferably, the housing is cylindrical. 
         [0018]    Preferably, the float valve includes a float and a stem. A valve seal may be located adjacent the end of the stem. 
         [0019]    Preferably, a fuel chamber is located adjacent the inlet in which fuel is passed. A shelter may be provided within the fuel chamber in which an end of the stem is located when the float valve assembly is in the open position 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Embodiment of the invention will be described with reference to the accompanying drawings in which: 
           [0021]      FIG. 1  is a section side view of a valve assembly with a breather float valve and an inlet float valve in an open position according to a first embodiment of the invention; 
           [0022]      FIG. 2  is a section side view of the valve assembly of  FIG. 1  with the breather float valve and the inlet float valve in a closed position; and 
           [0023]      FIG. 3  is a section side view of the valve assembly of  FIG. 1  with a relief valve in an open position. 
           [0024]      FIG. 4  is a sectional side view of the valve assembly of with a breather float valve in an open position according to a second embodiment of the invention; 
           [0025]      FIG. 5  is a sectional side view if the valve assembly of  FIG. 4  with a breather float valve in a closed position; and 
           [0026]      FIG. 6  is a schematic representation of the valve assembly connected to a control valve. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0027]      FIG. 1  shows a valve assembly  10  that is primarily used in a fuel tank  1 . The valve assembly  10  is normally used in conjunction with a control valve  2 , as described in U.S. Pat. No. 6,311,723, to prevent fuel from entering the fuel tank when the fuel tank has reached a predetermined level.  FIG. 6  shows the valve assembly  10  connected to the control valve  2  via a bleed pipe  3 . The control valve  2  is connected to a fuel pump  4  and supply tank  5 . 
         [0028]    The valve assembly  10  comprises a housing  20  that is hollow and substantially cylindrical in shape. The housing  20  has several fuel holes  21  located along its length that allow fuel located within the fuel tank to pass in and out of the housing  20 . 
         [0029]    An inlet  30  is provided at a lower end of the housing  20  through which passes fuel. The inlet  30  is fluidly connected to two separate screw threaded apertures  31  and  32 . The bleed pipe  3  is connected to one of the apertures  31  or  32 . The bleed pipe is fluidly connected to the control valve to activate the control valve as, disclosed in U.S. Pat. No. 6,311,723. The screw-threaded apertures  31  and  32  allow the bleed pipe to be connected outside or inside the fuel tank. 
         [0030]    An inlet float valve  40  is housed in a lower end of the housing  20 . The inlet float valve  40  is formed from a inlet float  41  and stem  42 . A valve seal  43  is located adjacent the end of the stem  42  for sealing the inlet  30 . 
         [0031]    The inlet float valve  40  is mounted within the housing so that the stem  42  can reciprocate between an open position, in which fuel is able to pass through the bleed pipe  3  and through the inlet  30  into the fuel tank  1 , and a closed position that prevents the flow of fuel through the inlet. 
         [0032]    A fuel chamber  50  is located between the inlet  30  and the apertures  31  and  32 . The fuel chamber  50  provides a shelter  51  in which an end of the stem  42  is located when the inlet float valve  40  is in the open position. 
         [0033]    The top of the housing  20  is open so that a passageway  60  is provided between the inside and outside of the fuel tank. This allows gas to pass from within the fuel tank to the atmosphere so that the fuel tank does not rupture during filling of the fuel tank. A relief plate  71  is positioned within an upper end of the housing  20 . Breather holes  72  are located within the relief plate  71 . The breather holes  72  form part of the passageway  60 . 
         [0034]    A breather float valve  80  is provided adjacent the breather holes. The breather float valve  80  is formed from a breather float  81  and a rod  82 . A platform  83  and the relief plate  71  guide rod  82 . The float  81  is able to reciprocate along the length of the rod  82  between the relief plate  71  and the platform  83 . The rod  82  is fixed to the float  81  with circlips. 
         [0035]    The breather float valve  80  is in an open position when the breather float  81  is located adjacent the platform  83  and gas is free to pass through the breather holes  72 . The breather float valve  80  is in a closed position when the breather float  81  is located over the breather holes  72  and fuel cannot pass through the breather holes  72 . 
         [0036]    A relief valve  70  is formed adjacent a top end of the housing  20 . The relief valve  70  is formed from the relief plate  71 , a spring  73  and a cap  74 . The relief plate is able to move within a skirt  22  formed at the top of the housing  20 . The skirt  22  has a number of circumferentially spaced relief holes  23 . The spring  73  holds the relief plate at the base of the skirt  22 . The spring  73  is held in position by a cap  74  that is located over the housing  20 . 
         [0037]    In use, the valve assembly  10  has a number of functions. In a fuelling normal operation, the inlet float valve  40  is in the open position such that the stem  42  sits within the shelter  51  as shown in  FIG. 1 . The bleed pipe  3  passes fuel in to the fuel chamber  50 . The fuel then passes through the inlet  30 , into the housing  20  and out the fuel holes  21  into the fuel tank. Any turbulence that is created by the fuel passing through the fuel chamber  50  does effect the valve seal  43  as it is located within the shelter  51 . 
         [0038]    As the fuel tank fills with fuel, the passageway  60  of the housing  20  also fills with fuel to the same level. The inlet float  41  rises within the housing until the valve seal  43  blocks the inlet  30  as shown in  FIG. 2 . The pressure of the fuel within the bleed pipe, as well as the fuel within the tank acting on float, maintains the valve seal  43  in position within the inlet  30 . Once the inlet  30  is blocked, the bleed pipe  3  fills with fuel causing the control valve  2  to become closed and prevents further filling of the fuel tank. 
         [0039]    When the vehicle is moving, the housing  20  prevents damage of the inlet float valve  40 . The impact forces created by surging fuel within the fuel tank impact the housing  20  not the inlet float valve  40 . 
         [0040]    However, the surging fuel can still extend up passageway  60  and up to the breather holes  72 . The breather float valve  80  prevents this surging fuel from escaping through the breather holes  72  as the breather float  81  moves with the surging fuel blocking the breather holes  72  as shown in  FIG. 2 . 
         [0041]    The breather float valve  80  also provides a fail safe during fuelling of the fuel tank. If the bleed pipe  3  is severed or the control valve fails or the inlet float valve fails, then a fuel supply nozzle (not shown) will continue to pump fuel into the fuel tank. The fuel tank will fill with fuel until the breather float  81  moves to the closed position to block the breather holes  72 . The continued fuelling of the fuel tank creates pressure within the fuel tank. When the fuel tank reaches a fuel nozzle shut off pressure, then the fuel supply nozzle will shut-off stopping the fuel tank from rupturing. 
         [0042]    If the fuel supply nozzle does not shut off automatically due to a mechanical fault, then the fuel supply nozzle will continue to supply fuel to the fuel tank. This causes the pressure within the fuel tank to increase. At a pressure less than the rupture pressure of the tank, the pressure relief valve is opened as shown in  FIG. 3 . This occurs when the fuel tank pressure becomes greater than the spring pressure causing the relief plate  71  to move upwardly until it passes over the relief holes  23  in skirt  22 . Fuel then passes from the tank, through the relief holes  23 , into the cap  74  and through a cap hole  75 . The fuel flowing from the cap  74  will indicate to an operator to shut the fuel supply nozzle off manually. 
         [0043]      FIG. 4  and  FIG. 5  show a second embodiment of a valve assembly  10 . In this embodiment, a breather float valve spring  84  is mounted around the rod  82  on the modified platform  83  below the breather float  81 . The breather float valve spring  84  engages the breather float  81 . 
         [0044]    The breather float valve spring  84  assists in moving the breather float  81  to the closed position in the event of a vehicle roll over. The breather float  81  is of sufficient weight to compress the breather float valve spring  84  when the valve assembly is in a substantially vertical position. However, during a roll over, less force is applied by the breather float  81  on the breather float valve spring  84  when the valve assembly  10  moves from a substantially vertical position to a substantially horizontal position. Therefore, the breather float valve spring  84  causes the breather float  81  to move to the closed position so that fuel cannot escape from the tank through the breather holes  72  in the event of a vehicle roll over. 
         [0045]    The valve assemble provides a number of advantages. Firstly, the valve assembly is not damaged by surging fuel making the valve assembly suitable for use in vehicles. Secondly, the breather float valve prevents fuel from escaping the valve assembly when the fuel surges within the fuel tank during movement of the vehicle. Thirdly, in the event of failure of the inlet float valve, control valve or bleed pipe, the breather float valve prevents the loss of fuel by blocking the breather holes causing pressure build up within the fuel tank and thus causing the fuel supply nozzle to shut off. Lastly, the pressure relief valve prevents the fuel tank from rupturing from over pressurising of the fuel tank. 
         [0046]    The valve assembly can be easily retro fitted or fitted into existing tanks. It is sized to fit into holes that are located in tanks for existing systems. 
         [0047]    It should be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit or scope of the invention.