Abstract:
The invention relates to a gas filling and dispensing device that comprises a body to be positioned in the opening of a pressurized gas storage tank, a gas-tapping circuit extending between a first upstream end to be connected to the inside of the tank and a second downstream end to be connected to a gas user, wherein the tapping circuit includes a first insulation valve, the device further including a safety valve subjected to the tank pressure for blocking or selectively opening a passage for the gas from the tank towards a discharge area based on the temperature and/or pressure of the gas in the tank relative to at least one predetermined threshold, characterized in that the discharge area of the safety valve is located upstream from the first insulation valve.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation application of application Ser. No. 12/867,395, filed internationally on Feb. 9, 2009 as a 371 of International PCT Application PCT/FR2009/050202 which claims priority to French Application 0850946, filed Feb. 14, 2008, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a gas filling and dispensing device, to a vessel and to a user circuit provided with such a device. 
       SUMMARY 
       [0003]    The invention relates more specifically to a gas filling and dispensing device comprising a body intended to be positioned in the orifice of a pressurized-gas storage reservoir, a gas withdrawing circuit running between an upstream first end intended to be connected to the inside of the reservoir and a downstream second end intended to be connected to a user of the gas, the withdrawing circuit comprising a first isolating valve, the device further comprising a safety relief valve intended to be subjected to the pressure in the reservoir in order selectively to close off or open a passage for the gas from the reservoir to a discharge zone according to the temperature and/or the pressure of the gas in the reservoir with respect to at least one set threshold. 
         [0004]    Devices or valves, notably those with in-built regulators, for gaseous applications are known. In particular, for vehicle or fuel applications involving gaseous hydrogen, gas storage at very high pressure (700 bar and beyond) is planned. One solution is notably to plan for users to swap empty reservoirs for full reservoirs (particularly in zones where filling stations are inappropriate). 
         [0005]    Current or future regulations anticipate the need for safety exhaust valves (PRDs) to release the gas stored in the reservoir in the event of a shock or fire (with a view to applications in vehicles in particular). 
         [0006]    However, the applicant company has noticed that such a safety pressure relief valve (PRD) could create problems when several reservoirs of this type are being stored in a storage zone prior to use. The problem is that when the gas is flammable or dangerous, such as hydrogen, the activation of one safety pressure relief valve and the creation of a flame could, through a “domino” or “chain reaction” effect, cause the safety relief valves of the adjacent reservoirs to activate. 
         [0007]    To solve this problem, one possible solution is to provide heat screens on the reservoirs or in their storage zone. However, these solutions are expensive and somewhat unsatisfactory. 
         [0008]    It is an object of the present invention to alleviate all or some of the abovementioned disadvantages of the prior art. 
         [0009]    To this end, the gas filling and dispensing device according to the invention, in other respects according to the generic definition given thereof in the above preamble, is essentially characterized in that the discharge zone of the safety relief valve is situated upstream of the first isolating valve. 
         [0010]    Furthermore, some embodiments of the invention may comprise one or more of the following features:
       the withdrawing circuit comprises a pressure regulator, a low-pressure chamber and the first isolating valve which are arranged in series in that order from the upstream to downstream end, the discharge zone of the safety relief valve being situated downstream of the pressure regulator,   the safety relief valve is situated in a pipe having a downstream end connected upstream of the first isolating valve and an upstream end connected, when in position mounted on a reservoir, to the inside of the reservoir,   the gas withdrawing circuit comprises a second isolating valve,   the second isolating valve is arranged between the pressure regulator and the first isolating valve,   the discharge zone of the safety relief valve is situated between the first and second isolating valves,   the safety relief valve comprises a fusible element butting against a member that is able to move selectively between a position of shutting off the passage to the discharge zone when the fusible element is not activated and a position of opening the passage to the discharge zone when the fusible element is activated,   the moving member of the safety relief valve comprises a piston capable of translational movement in the body of the device and a system of seal(s) able to collaborate with a seat formed in said body,   the passage for the gas to a discharge zone comprises a groove, the positions in which the passage to the discharge zone is closed off and opened being defined by the positions of the system of seal(s) relative to the groove,   the moving member of the safety relief valve comprises a piston of the differential type only a determined fraction of the working surface area of which is subjected to the pressure in the reservoir so as to limit the force transmitted by the piston to the fusible element to a set value.       
 
         [0020]    The invention also proposes a pressurized gas vessel comprising, arranged in its orifice, a gas filling and dispensing device according to any one of the features described hereinabove or hereinbelow. 
         [0021]    According to another possible aspect, the applicant company is also proposing an assembly comprising a circuit for using a pressurized gas and a pressurized gas vessel according to any one of the features described hereinabove or hereinbelow, the vessel being selectively connectable to the user circuit via the gas filling and dispensing device, the circuit comprising a mechanism that forms a high-pressure safety relief valve able to discharge the pressurized exhaust gas to the atmosphere or to a set safe zone. 
         [0022]    According to one advantageous possible feature, the user circuit comprises a member (such as a spindle) that has a first position in which the first valve is selectively open (the second valve is closed) and a second position in which the first and second valves are open. 
         [0023]    The invention may also relate to any alternative device or method comprising any combination of the method and/or device features listed hereinabove or hereinbelow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    For a further understanding of the nature and objects for the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein: 
           [0025]      FIG. 1  depicts a perspective and schematic view illustrating one possible embodiment of a gas filling and dispensing device according to the invention, 
           [0026]      FIGS. 2 to 4  schematically depict the structure and operation of three possible and nonlimiting embodiments of the gas filling and dispensing device according to the invention, 
           [0027]      FIG. 5  is a view in longitudinal section of the gas filling and dispensing device of  FIG. 1  on a first plane of section, 
           [0028]      FIG. 6  depicts a view in longitudinal section of the gas filling and dispensing device of  FIG. 1 , in position mounted in a reservoir and on a second plane of section (embodied by the line A-A in  FIG. 5 ), 
           [0029]      FIG. 7  depicts a view in cross section of the gas filling and dispensing device of  FIGS. 1 and 5  on a first plane of section (embodied by the line B-B in  FIG. 5 ), 
           [0030]      FIG. 8  depicts a cross section of the gas filling and dispensing device of  FIGS. 1 and 5  on a second plane of section (embodied by the line C-C in  FIG. 5 ), 
           [0031]      FIG. 9  depicts a view in longitudinal and partial section of the gas filling and dispensing device of  FIGS. 1 ,  2  and  5  to  9  in position coupled to a user component. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0032]    The invention will now be described with reference to  FIGS. 1 to 9  which illustrate entirely nonlimiting application examples. In particular, the invention can also be applied to any other type of device or valve. The invention may notably be applied to the devices described in documents WO 2007/048954 A1 or WO 2007/048957. 
         [0033]    The gas filling and dispensing device comprises an oblong body  1  the lower end of which is intended to be lodged preferably in part in a reservoir. The device notably incorporates a gas pressure-relief portion (pressure regulator  50 ) and a coupling region  101  (such as a screw thread or the like) for fixing it into the neck of a reservoir (cf.  FIGS. 1 ,  5  and  6 ). The upper end of the device forms a head  111  (for example out of the reservoir notably comprising a safety relief valve  55 , a gas filling/withdrawing orifice  301  and connection members  201  which are intended to collaborate with complementary connection members belonging to a user system (which has not been depicted in  FIG. 1 ). 
         [0034]    With reference to  FIG. 5 , the device comprises a withdrawing circuit  20  comprising, from the downstream to upstream direction (that is to say from the external orifice  301  toward the reservoir): a first valve  160 , a second isolating valve  60  and a pressure regulator  50 . 
         [0035]    Of course the device may comprise other members which for the sake of conciseness have not been described. In particular, regarding the detail of the internal arrangement of the device  1  (regulator, filter(s), valve(s)), reference may, for example and entirely nonlimitingly, be made to document WO 2007048957. 
         [0036]      FIG. 2  schematically depicts one possible structure according to the invention. The withdrawing circuit  20  comprises, from the upstream to downstream direction, a filter  120 , a non-return valve  220 , the regulator  50 , the second isolating valve  60  and the first isolating valve  160  (the latter is preferably coupled to quick fit connection means intended to collaborate with a filling/withdrawing tapping of a user system  40 ). The device  1  comprises a filling pipe  240 , preferably distinct from the withdrawing circuit  20 . The filling circuit  240  comprises a valve  140  and has one end connected for example upstream of the filter  120  and another end connected upstream of the first valve  160 . 
         [0037]    The device  1  further comprises a safety relief valve  55  housed in a pipe  155  connected, on the one hand, to the inside of the reservoir  30  (upstream of the filter  120 ) and, on the other hand, upstream of the first valve  160 . 
         [0038]    Thus, any gas that may be discharged by the safety relief valve  55  is directed into the low-pressure chamber which is isolated from the outside by the first valve  160 . This then avoids the release of dangerous/flammable gases to the outside and reduces the risk of external combustion. The gas released by the safety relief valve  55  is rather released to the outside in a controlled fashion via the outlet orifice  301  (the orifice used for withdrawing and preferably also for filling). For example, this discharge gas is discharged by the user member that is connected to the device when it opens the first valve  160  (for example via a system provided for that purpose). This is particularly advantageous from a safety standpoint, particularly in the case of applications that use a fuel containing gaseous hydrogen (vehicles). 
         [0039]      FIGS. 5 to 9  illustrate one nonlimiting exemplary embodiment in greater detail. 
         [0040]    The gas G contained in the reservoir  30  enters the body of the device via a pipe  155  (see  FIGS. 7 and 8 ) comprising a nozzle  37  and opens radially in the region of a moving piston  6  that forms part of the safety relief valve  55  mechanism. 
         [0041]    The piston  6  is subjected to the pressure of the gas in the direction of an end stop comprising a component  8  made of a fusible material such as a eutectic alloy made up, for example, of tin and/or of bismuth and/or of lead and a porous plug  9 . 
         [0042]    As depicted, the piston  6  is preferably of the differential type, that is to say that just part of its surface area (cross-sectional area) is subjected to the pressure of the gas, so as to limit the force transmitted to the fusible material  8 . Of course, any other type of arrangement and geometry of the piston  6  and fusible material  8  may be envisioned. 
         [0043]    The gas emerges around the piston  6  in a circular groove  255  (cf.  FIG. 8 ). Under normal circumstances, the gas remains confined to this groove  255  by means of a pair of O-ring seals  10 ,  12  each associated with an anti-creep ring  11 ,  13 . The seals  10 ,  12  and anti-creep rings  11 ,  13  are carried by the piston  6  and are spaced apart in the longitudinal direction of the piston  6 . The first seal  12  situated on the fusible material side is preferably larger in size than the second seal  10 . This second seal  10  provides sealing towards the outside by preventing gas from escaping there. The first seal  12  provides sealing with respect to the internal circuit of the body of the device. More specifically, the first seal  12  prevents the gas from reaching a second groove  80  which communicates with the low-pressure chamber situated between the two valves  60 ,  160  of the withdrawing circuit  20  (in the example depicted, the piston  6  slides in a direction substantially perpendicular to the longitudinal direction of the withdrawing circuit  20 ). The piston  6  may have a third seal  14  and anti-creep ring assembly on the fusible element  8  side. 
         [0044]    This low-pressure chamber situated downstream of the second valve  60  therefore also receives the gas expanded by the regulator  50  when the second valve  60  is open (for example via a dip member that forms part of the user system, cf.  FIG. 9 ). 
         [0045]    As depicted in  FIG. 6 , this low-pressure chamber is isolated from the outside via the first valve  160  made up of a shutter  33  capable of translational movement and subjected to the action of a return spring  22  returning it towards a position in which the outlet orifice  301  is closed. All the sealing required in order for this valve  160  to function may be afforded by the O-ring seals  24 ,  25 ,  26  and  126  which are associated respectively with the anti-creep rings  27 ,  127 ,  28  and  128 , each of these seal/ring pairs [ 24 ; 27 ], [ 25 ; 127 ], [ 26 ; 28 ] and [ 126 ; 128 ] being housed in a channel of a cannula  23 . Said cannula  23  is contained inside the body of the device  1  via a cover  4  connected to the body of the device  1  by the fixing elements  401  (see  FIG. 1 ). The seal/ring pairs [ 26 ; 28 ] and [ 126 ; 128 ] are situated on the external cylindrical surface of the cannula  23  on each side of radial holes  231  formed in the cannula  23  so as to ensure sealed continuity of the filling pipe  240  between the body of the device  1  and the cannula  23 . The seal/ring pairs [ 25 ; 127 ] and [ 24 ; 27 ] are situated on the internal cylindrical surface of the cannula  23  on each side of the radial holes  231  formed in the cannula  23  so as to ensure sealed continuity of the filling pipe  240  between the reservoir filling tool (when connected) and the cannula  23  or, in the case of the seal/ring pair [ 24 ; 127 ] so as to form a second barrier for gas between the shutter  33  (when it has been returned by the spring  22  to a position in which the orifice  301  is closed) and the cannula  23 . 
         [0046]    When the safety relief valve  55  is active (the pressure and/or the temperature has exceeded a threshold), the fusible material  8  is no longer able to withstand the force transmitted by the piston  6  and moves aside. As a result, under the action of the pressure of the gas, the piston  6  moves toward the volume opened up by the fusible element  8  (to the left in  FIG. 8 ) and the first seal  12  of the piston  6  then enters the second groove  80 , doing away with the sealing with respect to the internal circuit. The gas G from the pipe  155  is then allowed to enter this groove  80  and access the low-pressure chamber upstream of the first valve  160 . 
         [0047]    The piston  6  is dimensioned to prevent the second seal  10  from entering the first groove  255 , so as to maintain sealing at the other end of the piston  6 . 
         [0048]    When the device  1  is not connected to a user system, the seal  24  and the moving shutter  33  prevent gas from escaping to the outside. By contrast, when the device is connected to a user system, a spindle  44  may enter the orifice  301  of the device. The spindle  44  may, for example, have radial orifices  144  at its end to communicate with the low-pressure chamber. The gas then passes, for example, via a central channel formed in the spindle  44 . The seal  24  seals against the spindle  44 . 
         [0049]      FIG. 9  depicts the device  1  connected to a user system  40  of which the spindle  44 , fitted into the orifice  301 , is sealed against the O-ring/anti-creep ring pair [ 24 ; 27 ]. The end of the spindle  44  is in contact with the end of the moving shutter  33 , forcing it to move in the direction of the second valve  60  by overcoming the force of the return spring  22 . The spindle  44  may have two stable and distinct positions. A first stable position in which the spindle  44  causes the moving shutter  33  to move without opening the second valve  60  (the expanded gas from the regulator  50  is not delivered to the user system) and a second position in which the spindle  44  causes the moving shutter  33  to move and open the second valve  60  (the expanded gas from the regulator  50  is delivered to the user system). As soon as the device  1  is connected to a user system  40 , whichever of the two aforementioned stable positions the spindle  44  is occupying, any stream of gas arriving in the low-pressure chamber from the safety relief valve  55  via the pipe  155  is discharged to the outside via the radial orifices  144  and the central channel of the spindle  44 . 
         [0050]      FIG. 3  schematically illustrates the connection between the reservoir  30 /device  1  assembly and a user  40  circuit  100  comprising a safety mechanism  950 . 
         [0051]    The high-pressure gas escaping from the reservoir (contained in the low-pressure chamber in the event of overheating or an anomaly) is managed by the user circuit  100  when the user member  40  opens the first valve  160 . This high-pressure exhaust gas can be discharged to the safety relief valve  950  which, thanks to a discharge shaft or the like, leads the fluid into the atmosphere in a known controlled area (particularly when the circuit  100  forms part of a vehicle). 
         [0052]    When the user member opens the second valve  60 , the expanded gas is then allowed to enter the user circuit  100 . 
         [0053]    Thus, any gas discharged (in the event of a raised pressure or an abnormally high temperature) leaves via the orifice  301  (which is preferably a single orifice) which is also used for filling and possibly for withdrawing. 
         [0054]    The gas thus uses one and the same orifice  301  for filling/withdrawing/discharging in the event of overpressure. This allows for a single connection to the reservoir and therefore simplifies the operations for a user. The gas discharged in the event of overpressure in the reservoir can thus be collected via this orifice toward a user circuit  100 , toward a safe area. This feature is particularly advantageous when the gas is a hazardous gas such as hydrogen. 
         [0055]    Of course, the invention is not restricted to the exemplary embodiment of  FIGS. 5 to 9  any more that it is restricted to the structure of  FIGS. 2 and 3 . Thus, for example,  FIG. 4  illustrates an embodiment variant in which the device has just one isolating valve  60 . In this case, any gas that might be released by the safety relief valve  55  can be directed between the regulator  55  and the valve  60 . 
         [0056]    Of course, it is possible to conceive of other types of arrangement (in which the discharge region of the safety relief valve  55  is upstream of the two valves  60 ,  160  of  FIG. 2 ). 
         [0057]    Likewise, the invention can be applied to a gas filling and distributing device that does not have a pressure regulator  50 . 
         [0058]    It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above.