Abstract:
A metering valve for dispensing a fluid, said metering valve comprising a valve body ( 10 ) and a valve member ( 20 ) mounted to slide relative to said valve body ( 10 ) between a rest position and a dispensing position, said valve further comprising a metering chamber ( 11 ) serving to contain the metered quantity or “dose” of fluid discharged each time the valve is actuated, said metering valve being characterized in that, when it is in the rest position, said metering chamber ( 11 ) is at atmospheric pressure.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of pending U.S. provisional patent application Serial No. 60/485,387, filed Jul. 9, 2003, and priority under 35 U.S.C. §119(a)-(d) of French patent application No. FR-03.05857, filed May 15, 2003. 
     
    
     
       TECHNICAL FIELD  
         [0002]    The present invention relates to a metering valve and to a fluid dispenser device including such a valve.  
         BACKGROUND OF THE INVENTION  
         [0003]    Metering valves are well known from the state of the art, in particular for dispensing fluids in liquid or powder form. The fluid is generally associated with a propellant gas, and actuating the valve makes it possible to dispense a metered quantity or “dose” of fluid by means of said propellant gas. A metering valve generally includes a valve body defining a metering chamber, the valve member sliding in said metering chamber between a rest position and a dispensing position. When the valve member is in the rest position, said valve member is not connected to the inside of the metering chamber, and the metering chamber is connected to the reservoir so that it can be filled, generally by gravity, with the fluid and with the propellant gas, so as to define the dose of fluid to be dispensed the next time the valve is actuated. When the valve is actuated, the valve member is pushed into the valve body, and the passageway between the metering chamber and the reservoir is closed. Then, when the valve member reaches the vicinity of its dispensing position, the metering chamber is connected to the dispensing orifice of the valve member, thereby enabling the dose of fluid contained in the metering chamber to be discharged through the dispensing orifice of the valve member. When the user ceases to press on the valve member, said valve member is returned automatically to its rest position by a return spring, and, during this operation, the metering chamber fills again with the fluid and with the propellant gas, generally by gravity when the valve is a valve used in the upside down position, i.e. with the metering valve under the reservoir. In known metering valves, the metering chamber is thus at the same pressure as the reservoir when the valve is in the rest position because said chamber is connected directly to said reservoir. This implies high stresses on the gaskets provided at the metering chamber, and risks causing fluid to return towards the reservoir during storage, when the valve is stored in the upright position. In order to avoid such fluid return from the metering chamber to the reservoir while the valve is being stored in the upright position, and thus in order to avoid reducing the next dose, the valve member is generally provided with internal channels of complex shapes, e.g. siphon shaped, but because of the pressure existing in the metering chamber, sustaining the full dose, and therefore metering accuracy are not absolutely guaranteed.  
           [0004]    In addition, in known metering valves, the return spring of the valve member is disposed in the body of the valve, and generally at the passageway connecting the metering chamber to the reservoir. The spring is thus in contact with the fluid and with the propellant gas. Depending on the material of the spring (generally metal) and on the type of the fluid, this can degrade said fluid.  
         SUMMARY OF THE INVENTION  
         [0005]    An object of the present invention is to provide a metering valve that does not reproduce the above-mentioned drawbacks.  
           [0006]    More particularly, an object of the present invention is to provide a metering valve that guarantees absolute metering accuracy each time the valve is actuated, as well as full dose reproducibility each time it is actuated.  
           [0007]    An object of the present invention is also to provide such a metering valve in which metering accuracy and dose reproducibility are independent of the time for which the valve is stored between occasions on which it is actuated.  
           [0008]    Another object of the present invention is to provide such a valve that avoids any risk of degrading the fluid, even when the valve is stored for a prolonged period.  
           [0009]    An object of the present invention is also to provide such a metering valve that is simple and inexpensive to manufacture and to assemble, and that is reliable to use.  
           [0010]    The present invention therefore provides a metering valve for dispensing a fluid, said metering valve comprising a valve body and a valve member mounted to slide relative to said valve body between a rest position and a dispensing position, said valve further comprising a metering chamber serving to contain the metered quantity or “dose” of fluid discharged each time the valve is actuated, said metering valve being characterized in that, when it is in the rest position, said metering chamber is at atmospheric pressure.  
           [0011]    Advantageously, the valve further comprises a filling chamber connected firstly to a fluid reservoir and secondly to said metering chamber, the passageway between the metering chamber and the filling chamber being closed when the valve is in the rest position and in the dispensing position, said passageway being open when the valve moves between its rest position and its dispensing position.  
           [0012]    Advantageously, said filling chamber is connected to said fluid reservoir when the valve is in the rest position, the passageway between the filling chamber and the reservoir being closed when the valve is not in the rest position.  
           [0013]    Advantageously, the metering chamber fills when the valve member moves from its rest position to its dispensing position.  
           [0014]    Advantageously, said valve member is provided with a link channel having an inlet and an outlet that is offset axially relative to said inlet, said link channel lying entirely within the metering chamber in the rest position, lying entirely within the filling chamber in the dispensing position, and connecting said metering chamber to said filling chamber when the valve member is between its rest position and its dispensing position, said inlet then being disposed in the filling chamber, and said outlet being disposed in said metering chamber.  
           [0015]    Advantageously, the fluid contained in the metering chamber is discharged when the valve member reaches its dispensing position.  
           [0016]    Advantageously, a spring urges the valve member towards its rest position, said spring being disposed out of any contact with said fluid.  
           [0017]    Advantageously, the valve body further comprises a spring chamber isolated from any contact with the fluid, the valve member passing through said spring chamber, and the spring being disposed in said spring chamber around said valve member.  
           [0018]    Advantageously, the valve member is provided with a central discharge channel connecting the dispensing orifice of the valve member to an opening that opens out into the metering chamber when the valve member is in the dispensing position, said opening being isolated from said metering chamber when the valve member is not in the dispensing position.  
           [0019]    Advantageously, the valve body comprises a spring chamber, a metering chamber, and a filling chamber, the spring chamber being separated from the metering chamber by a first transverse wall, the metering chamber being separated from the filling chamber by a second transverse wall, and the filling chamber being separated from the reservoir by a third transverse wall, said valve member sliding through said spring chamber, said metering chamber, and said filling chamber between its rest position and its filling position, by passing in leaktight manner through said first, second, and third transverse walls.  
           [0020]    The present invention also provides a fluid dispenser device including a metering valve as described above. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    Other characteristics and advantages of the present invention appear more clearly from the following detailed description of a particular embodiment of it, given with reference to the accompanying drawings which are given by way of non-limiting example, and in which:  
         [0022]    [0022]FIG. 1 is a diagrammatic section view of a metering valve of the present invention, when the valve is in the rest position;  
         [0023]    [0023]FIG. 2 is a view similar to the view in FIG. 1, when the valve is in an intermediate position, between the rest position and the dispensing position; and  
         [0024]    [0024]FIG. 3 is a view similar to the views of FIGS. 1 and 2, when the valve is in the dispensing position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]    The figures show a metering valve including a valve body  10 . The valve is assembled to a reservoir (not shown) which contains fluid, e.g. a liquid or a powder, generally associated with a propellant gas serving to enable the fluid to be dispensed through said valve. The valve body  10  may be assembled to said reservoir (not shown) by means of a fixing ring or of a fixing cap, in particular a crimp-on cap  5 , preferably with a valve member gasket  6  being interposed between the valve body  10  and said crimp-on cap  5 , and with a neck gasket (not shown) being interposed between the neck of the reservoir (not shown) and said crimp-on cap  5 . In the example shown in the figures, the valve body  10  has a thicker end edge  7  that serves to be fixed into said crimp-on cap  5 . Optionally, in particular when the valve is designed to be used in the upside down position, as it is in the example shown in the figures, the valve body  10  may be associated with a packing ring (not shown) serving to pack the dead volume between the reservoir neck and the crimp-on cap  5  at least in part, and/or to limit the contact between the fluid and the valve member gasket  6 .  
         [0026]    In the present invention, the valve body  10  includes a metering chamber  11  serving to contain a dose of fluid, which dose of fluid is dispensed whenever the valve is actuated. In the present invention, said metering chamber  11  is at atmospheric pressure when the valve is in the rest position. In other words, the metering chamber  11  is isolated from the fluid reservoir when the valve is in the rest position, so that no extra pressure is exerted on the gaskets defining said metering chamber  11  during storage, and so that there is no risk of the dose of fluid being reduced due to prolonged storage because, during storage, the metering chamber  11  is empty and does not contain any fluid. In the present invention, the metering chamber  11  fills only when the valve member  20 , which slides in the valve body  10 , moves from its rest position (shown in FIG. 1) to its dispensing position (shown in FIG. 3). The metering chamber  11  is filled between said rest position and said filling position, in the intermediate position shown in FIG. 2. For this purpose, the valve member  20  has a link channel  15  forming a passageway between the metering chamber  11  and a filling chamber  12  provided in the valve body  10 . The link channel is closed when the valve is in the rest position, in which said channel is disposed entirely within the metering chamber  11 . Similarly, said channel  15  is closed when the valve is in the dispensing position in which said channel is disposed entirely within the filling chamber  12 . It is only in the intermediate position shown in FIG. 2 that the link channel  15  connects the filling chamber  12  to the metering chamber  11 . As shown in the figure, the link channel  15  may have an inlet  15   a  and an outlet  15   b,  said inlet  15   a  being disposed in the filling chamber  12  and said outlet  15   b  being disposed in the metering chamber  11 , when the valve is in the intermediate position. When the valve member  20  reaches the intermediate position in which the link channel  15  connects the metering chamber  11  to the filling chamber  12 , the metering chamber  11  fills very rapidly due to the difference in pressure between the metering chamber and the filling chamber. Advantageously, said difference in pressure detaches any active fluid that is stuck to the walls of the filling chamber  12 , thereby guaranteeing that a full dose of active fluid is dispensed each time the valve is actuated.  
         [0027]    Preferably, the filling chamber  12  is connected to the reservoir (not shown) when the valve is in the rest position. Conversely, whenever the valve member  20  is actuated and it is moved axially inside the valve body, the passageway  16  between the filling chamber  12  and the reservoir is closed, thereby isolating said filling chamber  12  from said reservoir. Advantageously, the volume of the filling chamber  12  corresponds to the volume of the metering chamber  11 , so that, when the valve member goes into the intermediate position, the entire contents of the filling chamber  12  is emptied into the metering chamber  11  via the link channel  15 .  
         [0028]    In known manner, the valve member  20  is provided with an axial discharge channel  21  that opens out in a dispensing orifice  22 , said discharge channel  21  having an inlet orifice  23 . The inlet orifice  23 , which is generally radial, is organized to open out in the metering chamber  11  when the valve member is in the dispensing position. This means that the dose-of fluid contained in the metering chamber  11  is discharged through the valve member  20  when said valve member reaches the dispensing position, which is shown in FIG. 3, and which corresponds to the position in which the valve member  20  is pushed into the valve body  10 . When the valve member  20  returns from its dispensing position to its rest position, the link channel  15  goes back through the intermediate position in which it connects the filling chamber  12  to the metering chamber  11 . However, during this return stroke, the filling chamber  12  is empty and is isolated from the reservoir, as is the metering chamber  11 , so that said passageway causes no modification in the state of said chambers, and in particular does not fill the metering chamber  11 . Thus, when the valve member  20  comes into the vicinity of its rest position again, the metering chamber  11  is still at atmospheric pressure, as it was after the dose was dispensed when the valve was actuated the preceding time. The metering chamber  11  is thus at atmospheric pressure when the valve is in the rest position. Conversely, when the valve member  20  comes into its rest position, the filling chamber  12  is once again connected to the reservoir (not shown) via the passageway  16 , which enables said filling chamber  12  to be filled, in particular by gravity when the valve is used in the upside down position.  
         [0029]    Advantageously, the valve body  10  also includes a spring chamber  13  in which the spring  25  that urges the valve member  20  into its rest position is disposed. Advantageously, said spring  25  is disposed out of any contact with the fluid, as shown in the figures. This is obtained because the spring chamber  13  is disposed in the valve body  10  while being separated in leaktight manner from the metering chamber  11 , the valve member sliding in leaktight manner in said spring chamber  13 , and the spring  25  being disposed around said valve member  20  in said spring chamber  13 . Advantageously, the spring chamber  13  is separated from the metering chamber  11  by a first transverse wall  31  that is preferably associated with a sealing gasket against which said valve member  20  slides in leaktight manner. Similarly, said metering chamber  11  is separated in leaktight manner from the filling chamber  12  by a second transverse wall  32  which is also preferably associated with a gasket against which said valve member  20  slides in leaktight manner. Finally, the filling chamber  12  may also be advantageously separated from the reservoir (not shown) by a third wall  33 , also preferably associated with a gasket against which said valve member  20  slides in leaktight manner. Thus, the only link between the reservoir and the filling chamber  12  is provided by the passageway  16  which is closed as soon as the valve member  20  is no longer in the rest position. The only link between the filling chamber  12  and the metering chamber  11  is provided by means of the link channel  15 , which link channel is open only when the valve member  20  is in the intermediate position situated between its rest position and its dispensing position. Finally, the spring chamber  13  is never connected to the metering chamber  11 , or to the filling chamber  12 , or to the reservoir, so that the spring  25  is completely isolated from any contact with the fluid.  
         [0030]    This embodiment is particularly advantageous in that it guarantees firstly that the metering chamber  11  is at atmospheric pressure when the valve is in the rest position, which is particularly advantageous, in particular when the times between two occasions on which the valve is actuated are relatively long, and secondly that the spring  25  is never in contact with the fluid, thereby avoiding any risk of the fluid being degraded due to contact with the spring, which is generally made of metal.  
         [0031]    It should be noted that the spring may also be disposed at the bottom of the valve body, e.g. in the filling chamber, so as to limit the number of gaskets. In which case however, it is in contact with the fluid.  
         [0032]    The present invention thus makes it possible to obtain a metering valve that is particularly reliable, that guarantees that the dose is reproduced exactly and in full each time the valve is actuated while also being simple in construction and reliable to operate.  
         [0033]    Although the present invention is described with reference to a particular embodiment of it, it is naturally not limited to the embodiment shown in the drawings, but rather the person skilled in the art may make any necessary modifications to it without going beyond the ambit of the present invention, as defined by the accompanying claims.