Abstract:
A pushbutton for a system for dispensing a pressurized substance, the pushbutton including a body having a housing provided with an anvil around which a spray nozzle is mounted so as to form a substance dispensing path between the housing and a swirl array including a swirl chamber provided with a dispensing port as well as at least one supply duct for the chamber, the swirl chamber being defined by a side surface having a frusto-conical shape relative to which the supply duct(s) extend(s) in a transverse plane, the side surface tapering from an upstream end into which the downstream end of the supply duct(s) tangentially extends, to a downstream supply opening of the dispensing port, the dispensing port having an outlet size that is equal to the internal size of the downstream opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of pending International Patent Application PCT/FR2010/000726 filed on Nov. 2, 2010 which designates the United States and claims priority from French Patent Application 0905366 filed on Nov. 6, 2009, the content of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a push-button for a system for dispensing a product under pressure, as well as such a dispensing system. 
     BACKGROUND OF THE INVENTION 
     In a particular application, the dispensing system is intended to be provided on bottles used in perfumery, in cosmetics or for pharmaceutical treatments. Indeed, this type of bottle contains a product which is returned by a dispensing system comprising a device for sampling under pressure of said product, said system being actuated by a push-button in order to allow for the spraying of the product. In particular, the system for sampling comprises a pump or a valve with manual actuation by the intermediary of the push-button. 
     Such push-buttons are conventionally carried out in two portions: an actuator body and a spray nozzle for the product which are associated together to form a vortex unit comprising a vortex chamber provided with a dispensing orifice as well as with at least one supply channel of said chamber. 
     In particular, the supply channels exit tangentially in the vortex chamber which is cylindrical of revolution in order to rotate the product very rapidly, the dispensing orifice having a reduced diameter in relation to that of said chamber so that the product in rotation escapes through said orifice with a speed that is sufficient to be broken up into droplets forming the aerosol. 
     However, as this breaking up takes place in an uncontrolled manner, the aerosol is constituted of droplets of highly varied size. For example, for a pump or a valve supplying a push-button with a flow of alcohol under a pressure of 5 bars, and an outlet orifice of 0.3 mm, the aerosol is commonly constituted of droplets of a diameter between 5 μm and 300 μm. 
     However, the large droplets are heavier than the smallest ones and follow a different dispensing trajectory, which can cause indelible stains in the case of perfumes. Also, the small droplets are the lightest and can be inhaled, which may be the objective sought in the case of medications, but which can be an undesirable effect in the case of toxic products. Furthermore, in the case of medications which must be dispensed according to a precise dosage, the location of application, for example inside the respiratory system, depends on the size of the droplets, and the high disparity of sizes misrepresents the treatment. 
     Moreover, the size of the droplets coming from a vortex chamber depends in part on the force and on the speed with which the user actuates the pump by pressing on the push-button with his finger, as the induced pressure depends on this. 
     Furthermore, in particular due to the effects of the centrifugal force at the outlet of the vortex chamber, the aerosol has a tendency to be hollow with a substantially tapered shell which is constituted of most of the droplets although there are few inside the cone. In particular, this distribution of droplets can be detrimental for dermal applications. 
     It is known moreover, in particular from document FR-2 915 470, a push-button comprising a dispensing chamber which is provided with channels each converging towards an outlet orifice, said converging channels being arranged in order to allow for the impaction of the streams of product dispensed by said orifices. As such, during the impaction of the streams dispensed at high speed, an aerosol is formed without having recourse to a vortex chamber. 
     However, to produce such an aerosol by satisfactorily controlling the calibration and the spatial distribution of the droplets, it is necessary to form identical streams and of which the convergence is perfect, which is very difficult to carry out industrially at the interface between the actuator body and the nozzle mounted in said body. This results in that the streams can cross without impacting one another or in impacting one another only partially, which degrades the calibration and the spatial distribution of the droplets formed. 
     Moreover, the supply of the converging conduits or of the vortex chamber according to prior art does not allow for a breaking up of the dose of product to be dispensed, i.e. to return only a portion of the dose provided by the pump. Indeed, the travel of the pressing of the push-button is carried out too quickly, in particular by a magnitude of 0.2 seconds for 120 μl, to be able to be interrupted by the user. 
     SUMMARY OF THE INVENTION 
     The invention aims to resolve the problems of prior art by proposing in particular a push-button making it possible to dispense an aerosol formed of droplets having an improved calibration and spatial distribution, and this by increasing the duration of the production of said aerosol. 
     To this effect, and according to a first aspect, the invention proposes a push-button for a system for dispensing a product under pressure, said push-button comprising a body having a mounting well on a feed tube for the product under pressure and a housing in communication with said well, said housing being provided with an anvil around which a spray nozzle is mounted in such a way as to form a dispensing path for the product between said housing and a vortex unit comprising a vortex chamber provided with a dispensing orifice as well as least one supply channel of said chamber, said vortex chamber being delimited by a lateral surface having a tapered geometry in relation to which the supply channel or channels extend in a transversal plane, said lateral surface converging from an upstream end wherein tangentially exits the downstream end of the supply channel or channels towards a downstream opening for supplying the dispensing orifice, said dispensing orifice has an outlet dimension which is equal to the internal dimension of said downstream opening. 
     According to a second aspect, the invention proposes a dispensing system for a product under pressure, comprising a system for sampling provided with a feed tube for the product under pressure whereon the well of a push-button is mounted to allow for the spraying of the product. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objectives and advantages of the invention shall appear in the following description, provided in reference to the annexed figures wherein: 
         FIG. 1  is a partial longitudinal section view of a bottle provided with a dispensing system according to an embodiment of the invention; 
         FIG. 2  is a partial longitudinal section view of the push-button of  FIG. 1 ; and 
         FIG. 3  are views of the nozzle of the push-button according to the  FIG. 2 , respectively as a cutaway view ( FIG. 3   a ) and of the internal portion ( FIG. 3   b ). 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In relation with the figures, a push-button for a dispensing system for a product in particular liquid under pressure is described hereinbelow, said product able to be of any nature, in particular used in perfumery, in cosmetics or for pharmaceutical treatments. 
     The push-button comprises a body  1  having an annular skirt  2  which surrounds a well  3  for the mounting of the push-button on a feed tube  4  of the product under pressure. Moreover, the push-button comprises an upper zone  5  allowing the user to exert a finger press on said push-button in order to be able to displace it axially. In the embodiment shown, the push-button is provided with a trim  6  for aspect that surrounds the body  1  and whereon is formed the upper zone  5  for pressing. 
     In relation with  FIG. 1 , the dispensing system comprises a system for sampling  6  provided with a feed tube  4  of the product under pressure which is inserted in a sealed manner in the well  3 . In a known manner, the dispensing system further comprises means for mounting  7  on a bottle  8  containing the product and means for sampling  9  the product inside of said bottle which are arranged to supply the feed tube  4  with product under pressure. 
     The system for sampling  6  can include a pump with manual actuation or, in the case where the product is conditioned under pressure in the bottle  8 , a valve with manual actuation. As such, during a manual displacement of the push-button, the pump or the valve is actuated to supply the feed tube  4  with product under pressure. 
     The body  1  also has an annular housing  10  which is in communication with the well  3 . In the embodiment shown, the housing  10  has an axis perpendicular to that of the mounting well  3  in order to make possible a lateral spraying of the product relatively to the body  1  of the push-button. In an alternative not shown, the housing  10  can be collinear to the well  3 , in particular for a push-button forming a nasal spray tip. 
     The housing  10  is provided with an anvil  11  around which a spray nozzle  12  is mounted in such a way as to form a dispensing path for the product under pressure between said housing and a vortex unit. To do this, the anvil  11  extends from the bottom of the housing  10  by leaving a communication channel  13  between the well  3  and said housing. 
     In the embodiment shown, the nozzle  12  has a cylindrical lateral wall  14  of revolution which is closed towards the front by a proximal wall  15 . The association of the nozzle  12  in the housing  10  is carried out by press fitting of the external face of the lateral wall  14 , the rear edge of said external face being furthermore provided with a radial protrusion  16  for anchoring the nozzle  12  in said housing. 
     Furthermore, a print of the vortex unit is formed in a hollow in the proximal wall  15  and the anvil  11  has a planar distal wall  17  whereon the proximal wall  15  of the nozzle  12  is pressing against in order to delimit the vortex unit between them. In an alternative not shown, a print of the vortex unit can be formed directly on a wall of the housing  10 , in particular for a nasal spray tip. In another alternative not shown, the distal wall  17  can have a convexity turned towards the interior of the vortex unit. 
     Advantageously, the nozzle  12  and the body  1  are carried out by moulding, in particular from a different thermoplastic material. Furthermore, the material forming the nozzle  12  has a rigidity which is higher than the rigidity of the material forming the body  1 . As such, the substantial stiffness of the nozzle  12  makes it possible to prevent it from deforming when it is mounted in the housing  10  in such a way as to guarantee the geometry of the vortex unit. Furthermore, the less substantial stiffness of the body  1  allows for an improved seal between the well  3  for mounting and the feed tube  4 . 
     In the example embodiment, the body  1  is made of polyolefin and the nozzle  12  is made of cycloolefin copolymer (COC), poly(oxymethylene) or poly(butylene terephthalate). 
     In the embodiment shown, the dispensing path has successively in communication from upstream to downstream:
         an upstream annular conduit  30  in communication with the channel  13 , said annual conduit being formed between the rear portion of the internal face of the lateral wall  14  of the nozzle  12  and the portion of the external face of the lateral wall of the anvil  11  which is arranged across from it;   four axial conduits  18  formed between four spacers  19  which extend over the internal face of the lateral wall  14  of the nozzle  12 , said spacers having a free wall  20  which is press-fit on the external face of the lateral wall of the anvil  11 ;   a downstream annular conduit  21  formed between the proximal wall  15  of the nozzle  12  and the distal wall  17  of the anvil  11 .       

     On the downstream side, the dispensing path supplies with product under pressure the vortex unit which comprises a vortex chamber  22  provided with a dispensing orifice  23  as well as with at least one supply channel  24  of said chamber. More precisely, in the embodiment shown, the supply channels  24  communicate with the downstream annular conduit  21 . In particular, this embodiment makes it possible to limit the length of the supply channels  24  in order to reduce the induced head losses. 
     The vortex chamber  22  is delimited by a lateral surface  25  having a tapered geometry which extends along a dispensing axis D, the dispensing channels  24  extending in a transversal plane in relation to said dispensing axis. In the description, the terms of positioning in space are defined in relation to the dispensing axis. 
     In the embodiment shown, the tapered geometry is of revolution around the dispensing axis D, an internal dimension of said geometry thus corresponding to a diameter. In an alternative not shown, the tapered geometry can be of polygonal section, an internal dimension of said geometry thus corresponding to a diameter of the shell inscribed in said geometry. 
     The lateral surface  25  converges from an upstream end  26  wherein exits tangentially the downstream end of the supply channels  24  towards a downstream opening  27  for supplying the dispensing orifice  23 . Furthermore, the dispensing orifice  23  has an outlet dimension which is equal to the internal dimension of the downstream opening  27 . Advantageously, the angle of convergence of the lateral surface  25  can be between 30° and 50°, in particular of a magnitude of 45°. Moreover, in the embodiment shown, the upstream end  26  has a cylindrical geometry of revolution wherein the downstream end of the supply channels  24  exits tangentially. 
     As such, during the dispensing of the product under pressure, the tangential supply of the vortex chamber  22  makes it possible to put the product into rotation in the upstream end  26  of said chamber, the product is then thrust and pushed in rotation along the lateral surface  25  of said chamber by forming a pool of product of which the speed of rotation increases and which converges towards the downstream opening  27 , then said converging pool can escape through the dispensing orifice  23  without being deformed in such a way as to be able to be impacted to form the aerosol. 
     This embodiment therefore makes it possible to combine the advantages of the use of a vortex chamber  22  with that of the impaction of the product, without having the disadvantages therein, in particular relatively to the dispersion of sizes of droplets and to the risks of non-impaction of the product. The impaction of the swirling pool makes possible in particular the carrying out of an aerosol formed from a uniform spatial distribution of droplets in suspension in the air, the size of said droplets being small and uniform. In particular, the aerosol can then have the appearance of a plume of smoke with droplet sizes between 10 μm and 60 μm with an average of 35 μm for an alcoholic product, and this regardless of the pressing force that the user exerts on the push-button. 
     In the embodiment shown, the vortex unit has two supply channels  24  of the vortex chamber  22 , said channels being arranged symmetrically in relation to the dispensing axis D. 
     Moreover, to tangentially supply the vortex chamber  22  by causing the product to turn along its lateral surface  25 , each channel  24  has a U-shaped section which is delimited between an exterior wall  28  and an interior wall  29 . The exterior wall  28  is tangent to the upstream end  26  and the interior wall  29  is offset from it by a distance less than 30% of the internal dimension of the upstream end  26  in such a way as to avoid an impaction of the product in said upstream end. 
     In the embodiment shown, the interior wall  29  is parallel to the exterior wall  28 . In an alternative not shown, the interior wall  29  has an angle of convergence with the exterior wall  28  in the upstream-downstream direction, the offset between said walls then being measured on the section of exiting of the channels  24  in the upstream end  26 . 
     Alternatively, more than two supply channels  24  can be provided, in particular three channels  24  arranged symmetrically in relation to the dispensing axis D, or a single channel  24  can be provided to tangentially supply the vortex chamber  22 . 
     Moreover, the downstream end of the supply channel  24  or all of the downstream ends of each of the supply channels  24  forms a supply section of the vortex chamber  22 . In order to increase the duration of dispensing of a dose of product on the actuating stroke of the push-button, it can be provided that this supply section be low relatively to the interior surface of the upstream end  26 . In particular, the surface of the supply section can be less than 10% of the interior surface of the upstream end  26 . 
     Preferentially, the surface of the supply section can be between 0.01 mm 2  and 0.03 mm 2 . In an example embodiment, the internal dimension of the upstream end  26  is 0.6 mm, or an interior surface of 0.28 mm 2 , and each channel  24  has a width and a depth of 0.1 mm, or a surface of 0.02 mm 2  for the supply section. Alternatively, the channels  24  can have a width of 70 μm and a depth of 130 μm. 
     Furthermore, the fact of the passing of the product in a reduced supply section, the duration of dispensing is increased. For example, for a dose of 120 μl the duration of dispensing can be between 0.5 and 2 seconds in such a way as to allow the possibility for the user to interrupt the dispensing of the aerosol during actuation. 
     In the embodiment shown, the downstream opening  27  of the vortex chamber is surmounted by a dispensing orifice  23  having a cylindrical geometry of revolution around the dispensing axis D, the internal dimension of said orifice being equal to the internal dimension of the downstream opening  27 . 
     Advantageously, the axial dimension of the dispensing orifice  23  is low in relation to its internal dimension, in such a way as to not disturb the convergence of the swirling pool. In particular, the axial dimension of the dispensing orifice  23  can be less than 50% of its internal dimension. 
     In an alternative not shown, the downstream opening  27  of the vortex chamber  22  can form a dispensing orifice  23 . 
     The creating of the aerosol is particularly satisfactory when the internal dimension of the downstream opening  27  is low relatively to the internal dimension of the upstream end  26 , in such a way that the impaction of the pool is carried out as close as possible to the dispensing orifice  23 . In particular, the internal dimension of the downstream opening  27  can be less than 50% of the internal dimension of the upstream end  26 , more precisely by being between 20% and 40% of said internal dimension. 
     Preferentially, the axial dimension of the vortex chamber  22  is relatively substantial, in particular of a magnitude of or greater than the internal dimension of the upstream end  26 , in such a way as to allow for the establishment of the swirling pool along the lateral surface  25  of said vortex chamber and to confer a progressive convergence. In particular, the axial dimension of the vortex chamber  22  is at least equal to 80% of the internal dimension of the upstream end  26 , more precisely being between 90% and 200% of said internal dimension. 
     According to a particular embodiment in relation with a product of which the dispensing pressure is between 5 and 7 bars, the internal dimension of the upstream end  26  is 0.6 mm, the internal dimension of the downstream end  27  is less than or equal to 0.24 mm by being in particular between 0.15 mm and 0.24 mm, the axial dimension of the vortex chamber  22  is at least equal to 0.55 mm, the axial dimension of the dispensing orifice  23  is less than 0.10 mm.