Patent Publication Number: US-8528838-B2

Title: Push-button for a pressurized liquid distribution system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority of French patent application No. 09 01358 filed on Mar. 23, 2009, the content of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a push-button for a pressurised liquid distribution system, as well as such a distribution system. 
     BACKGROUND OF THE INVENTION 
     In one particular application, the distribution system is intended to equip bottles used in perfumery, cosmetics or for pharmaceutical treatments. As a matter of fact, this type of bottle contains a liquid which is delivered under pressure by a manually operated pump or valve by means of a push-button which is designed to enable spraying of the liquid. 
     Such push-buttons are conventionally made in two parts: an operating body and a spray nozzle that are combined together to form the push-button. In particular, the spray nozzle can be designed so as to form an aerosol with the liquid, in particular by defining a so-called vortex chamber. 
     To accomplish this, the vortex chamber is designed to make the liquid spin very rapidly so as to give it speed. Thus, by providing for the vortex chamber to be extended at the centre thereof via a distribution opening, the liquid can escape at high speed while fractionating itself into fine droplets forming the aerosol. 
     However, since this fractionation occurs in an uncontrolled manner, the aerosol consists of droplets of widely varied sizes. For example, for a pump or a valve supplying a push-button with a stream of alcohol under a pressure of 5 bars, and a 0.3-mm outlet opening, the aerosol commonly consists of droplets having a diameter of between 5 μm and 300 μm. 
     Such being the case, the large droplets are heavier than the smaller ones and follow a different distribution path, and are capable of causing indelible stains in the case of perfumes. Therefore, the small droplets are the lightest ones and can be inhaled, which may be the desired objective in the case of medications, but which can have an undesirable effect in the case of toxic products. Furthermore, in the case of medications which must be dispensed according to a precise dosage regimen, the location of application, e.g. inside the respiratory system, depends on the size of the droplets, and the large disparity in sizes distorts the treatment. 
     Furthermore, the size of the droplets derived from a vortex chamber depends in part on the force and speed with which the user operates the pump by pressing on the push-button with his finger, because the pressure induced depends on it. 
     Furthermore, and in particular because of the effects of the centrifugal force at the outlet of the vortex chamber, the aerosol has a tendency to be hollow with a substantially conical envelope which consists of the majority of the droplets, while there are few of same on the inside of the cone. In particular, this distribution of the droplets can be harmful in the case of dermal applications. 
     In order to solve the aforementioned problems, in particular the document FR-2 903 328 proposes to use a non-vortex nozzle which is provided with a micro-screen to ensure the calibration and spatial distribution of the droplets. 
     However, this embodiment necessitates flow areas through the micro-screen which are extremely small, in particular of the order of 6 μm in diameter, which requires fine filtration of the liquid in order to avoid clogging problems. Furthermore, the difficulty of producing and assembling these micro-screens in the body remains considerable. 
     A push-button is also known, in particular from the document FR-2 915 470, which includes a distribution chamber which is provided with channels each converging towards an outlet opening, said convergent channels being designed to enable the impaction of the liquid jets dispensed by said openings. Thus, during the impaction of the jets dispensed at high speed, an aerosol is formed, without the use of a vortex chamber. 
     In order to supply the convergent channels with liquid, the prior art proposes to equip the distribution chamber with an annular channel from which said convergent channels extend. This solution enables distribution of the streams of liquid introduced into each channel but poses a certain number of problems. 
     In particular, the liquid introduced into the annular channel under pressure becomes turbulent, which does not enable the streams of liquid introduced into the convergent channels to be stabilised. Furthermore, the speed of the liquid stream introduced remains low, which, while limiting the impaction energy of the liquid jets dispensed, does not enable an aerosol of optimum quality to be produced, in particular with respect to the fineness, calibration and spatial distribution of the droplets comprised in the same. 
     In addition, the supplying of the convergent channels according to the prior art does not enable fractionation of the dose of liquid to be dispensed, i.e. delivery of only a portion of the dose provided by the pump. As a matter of fact, the bearing-down stroke of the push-button is carried out too quickly, in particular of the order of 0.2 second for 100 μl, in order to be capable of being interrupted by the user. 
     The invention aims to solve the problems of the prior art, in particular by proposing a push-button which enables the dispensing of an aerosol formed of droplets having improved calibration and spatial distribution, and does so while increasing the production time for said aerosol. 
     SUMMARY OF THE INVENTION 
     To that end, and according to a first aspect, the invention proposes a push-button for a pressurised liquid distribution system, said push-button comprising a body onto which an end piece is mounted around an insert so as to form a distribution chamber between said end piece and said insert, said distribution chamber being in communication with a supply channel intended to be mounted on a feed tube for the pressurised liquid, said distribution chamber being successively connected to upstream channels, downstream channels and distribution channels, said distribution channels each converging towards an outlet opening while being designed to enable the impaction of the liquid jets dispensed by said openings, the upstream and downstream channels extending longitudinally while forming an upstream and downstream fluid flow section, respectively, in the distribution chamber, said downstream section having an average transverse surface which is less than the average transverse surface of the upstream section. 
     According to a second aspect, the invention proposes a pressurised liquid distribution system comprising a pressurised device for withdrawing the liquid, on which such a push-button is mounted, the distribution chamber being in communication with the feed tube for the pressurised liquid coming from said withdrawing device, so as to enable the liquid to be sprayed via impaction of the jets coming from the distribution channels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects and advantages of the invention will become apparent in the following description, which is made with reference to the appended figures, in which: 
         FIG. 1  is a partial perspective view of a distribution system according to the invention, said system being mounted on the mouth of a bottle; 
         FIG. 2  is an enlarged view of  FIG. 1  showing the dispensing end of the push-button; 
         FIG. 3  are longitudinal sectional views of a push-button according to an embodiment of the invention, respectively, in which the envelope of the dispensed liquid is diagrammed; 
         FIG. 4  is a perspective view of an insert according to a first embodiment of the invention; 
         FIG. 5  are longitudinal sectional ( FIG. 5   a ) and bottom ( FIG. 5   b ) views, respectively, of an end piece intended to be mounted around the insert according to  FIG. 4 ; 
         FIG. 6  is a perspective view of an insert according to a second embodiment of the invention; 
         FIG. 7  are longitudinal sectional ( FIG. 7   a ) and quarter-sectional ( FIG. 7   b ) views, respectively, of an end piece intended to be mounted around the insert of  FIG. 6 ; 
         FIG. 8  is a longitudinal sectional view of a push-button according to another embodiment of the invention; 
         FIG. 9  is a perspective view of the insert of the push-button according to  FIG. 8 ; 
         FIG. 10  is a longitudinal sectional view of the end piece intended to be mounted around the insert according to  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A push-button  1  for a pressurised liquid distribution system is described below in connection with the figures, said liquid potentially being of any type, which is used, in particular, in perfumery, cosmetics or for pharmaceutical treatments. 
     The distribution system likewise includes a pressurised device  2  for withdrawing the liquid, which is operated manually by means of the push-button  1 . In particular, the withdrawing device  2  can include a pump or a valve, in the case where the liquid is packaged under pressure. 
     In connection with  FIG. 1 , the push-button  1  is mounted on a feed tube for the pressurised liquid coming from the withdrawing device  2 , the distribution system being mounted on the mouth of a bottle  3  containing the liquid so as to supply the push-button  1  with said pressurised liquid. 
     The push-button  1  includes a body having an annular-like skirt  4 , which surrounds a housing  5  for mounting onto the feed tube for the pressurised liquid. In addition, the push-button  1  includes an upper region  6  enabling the user to exert finger pressure on said push-button so as to be capable of moving same axially in order to actuate the withdrawing device  2 . 
     The push-button  1  likewise includes an end piece  7 , which is mounted around an insert  8  so as to form a distribution chamber between said end piece and said insert. In the embodiments shown, the body of the push-button  1  has a housing  9  in which the insert  8  is arranged in order to enable the liquid to be sprayed laterally relative to the body of said push-button. 
     The insert  8  can be made integral with the body of the push-button  1  ( FIG. 3   a ) or inserted into the housing  9  ( FIGS. 3   b ,  8 ). In addition, the exterior wall of the end piece  7  has an anchoring ring  7   a  in the wall of the housing  9  so as to enable said end piece to be connected in said housing. 
     The distribution chamber is in communication with a supply channel  10  the upstream portion  10   a  of which terminates in the housing  5  for mounting onto the feed tube for the pressurised liquid. In the embodiments shown, the upstream portion  10   a  is coaxial with the housing  5  and the supply channel  10  has a downstream portion  10   b,  which is perpendicular to said housing. According to another embodiment, e.g. for a nosepiece, the downstream portion  10   b  can have an axis which is parallel to that of the upstream portion  10   a.    
     The distribution chamber is successively connected to upstream channels  11 , downstream channels  12  and distribution channels  13 . In order to enable the liquid to be sprayed while forming an aerosol, the distribution channels  13  each converge towards an outlet opening  14 , while being designed to enable the impaction of the liquid jets dispensed by said openings. In particular, the distribution channels  13  can converge at a point C, at an angle of the order of 70°, so as to produce the aerosol A in immediate proximity to the outlet openings  14 . 
     In the figures, the upstream  11  and downstream  12  channels are formed in the free space which is formed at the interface between an interior wall of the end piece  7  and an exterior wall of the insert  8 , a concave impression being formed on at least one of said walls so as to be closed by the other wall while defining said channels. 
     In particular, the impression can be made concave on one wall, and the other wall has a complementary surface which closes said concavities radially so as to form the channels  11 ,  12  along said concavities. In the embodiments shown, the concavities are made on the exterior wall of the insert  8 , and the interior wall of the end piece  7  is rotating, however the reverse configuration is foreseeable. 
     In  FIGS. 1 to 7 , the insert  8  has a base  15  over which a rod  16  extends, the exterior wall of said insert then comprising an upstream bearing surface  15   a  formed around said base and a downstream bearing surface  16   a  formed around said rod. Furthermore, the outside diameter of the upstream bearing surface  15   a  of the base  15  is greater than the outside diameter of the downstream bearing surface  16   a  of the rod  16 . 
     In the same way, the interior wall of the end piece  7  has an upstream bearing surface  17  and a downstream bearing surface  18  which are arranged opposite to those of the insert  8 , in order to form therebetween the upstream  11  and downstream  12  channels, respectively. In particular, the inside diameter of the upstream bearing surface  17  is greater than the inside diameter of the downstream bearing surface  18 . 
     Two embodiments are described below, in connection with  FIGS. 4 to 7 , for forming the upstream channels  11  around the base  15  and the downstream channels  12  around the rod  16 . The upstream  11  and downstream  12  channels extend longitudinally over the bearing surfaces  15   a,    16   a  while forming an upstream and downstream flow area, respectively, for the fluid in the distribution chamber, said areas having an average transverse surface which corresponds to the average of the transverse surfaces across which the fluid flows in the channels  11 ,  12 . In particular, the transverse surface of the upstream and downstream areas corresponds to the sum of the transverse surfaces of the upstream  11  and downstream  12  channels, respectively. 
     The invention provides for the average transverse surface of the downstream area to be less than the average transverse surface of the upstream area. Thus, the speed of the liquid increases from upstream to downstream so as to be capable of supplying the convergent channels  13  with a liquid flow the speed of which is considerable. This results in a significant degree of impaction energy, thereby enabling production of an aerosol A consisting of a uniform spatial distribution of airborne droplets, the size of said droplets being small and uniform. In particular, the aerosol A may then have the appearance of a plume of smoke. 
     Furthermore, due to the passage of the liquid in a downstream area having a small transverse surface compared to that of the upstream area, the distribution time of a dose of liquid over the operating stroke of the push-button  1  is increased. In particular, the distribution time for a 100-μl dose may be between 0.5 and 2 seconds, so as to allow the user the possibility of interrupting the dispensing of the aerosol A during operation. 
     The upstream bearing surface  15   a  of the base  15  has knurls  19  which extend longitudinally in relief over the cylindrical rotating surface of said bearing surface, an upstream channel  11  being formed between two adjacent knurls  19 . Each knurl  19  has a central region  19   a  the outside diameter of which corresponds substantially to that of the upstream bearing surface  17  of the end piece  7 , so as to enable said end piece to be centred over and fitted onto said knurls. 
     Upstream from the knurls  19 , the base has a cylindrical crown  20  around which an annular channel  21  of the distribution chamber is formed while being interposed between the upstream portion  10   b  of the supply channel  10  and the upstream channels  11 . Thus, the pressurised liquid coming from the feed tube passes into the supply channel  10  in order to fill the annular channel  21 . Because of the changes in direction, the stream of liquid is then turbulent, and passes next into the upstream channels  11  inside of which it stabilises, and then accelerates in the downstream channels  12  before supplying the distribution channels  13 . 
     In addition, in the embodiments shown, the downstream bearing surface  16   a  of the rod  16  has longitudinal grooves in which a downstream channel  12  is formed, respectively, said grooves being in communication with the upstream channels  11 . 
     In the first embodiment ( FIGS. 4 and 5 ), the knurls  19  have a truncated cone-shaped downstream region  19   b  which extends up to the radial joining surface between the base  15  and the rod  16 , the complementary region of the end piece  7  being designed to form an intermediate channel  22 , which is interposed between the upstream  11  and downstream  12  channels. 
     In particular, the joining region is annular so as to be capable of forming an annular intermediate channel  22  in which the upstream  11  and downstream  12  channels terminate. In  FIGS. 4 and 5 , the end piece  7  has integral bridges  23 , which are designed to break up the annular channel so as to form several intermediate connecting channels  22  between the upstream  11  and downstream  12  channels. 
     Furthermore, the number of upstream channels  11  is different from that of the downstream channels  12 , since four upstream channels  11  communicate with three downstream channels  12 . According to the first embodiment, the difference in the transverse surface between the upstream and downstream areas is thus obtained by providing for more upstream channels  11  than downstream channels  12 . As an alternative to this embodiment, an identical number of upstream  11  and downstream  12  channels can be formed and, as shown, the width of the upstream channels  11  is greater than that of the downstream channels  12 , so as to increase the speed of the liquid from the upstream area to the downstream area of the distribution chamber. 
     In the second embodiment ( FIGS. 6 and 7 ), the number of upstream channels  11  is equal to the number of downstream channels  12 , each upstream channel  11  being in longitudinal alignment with a downstream channel  12 , so as to limit the head loss at the junction between these channels  11 ,  12 . 
     To accomplish this, the grooves of the rod  16  extend between the knurls  19 , and the difference in transverse surface area between the area of the upstream  11  and downstream  12  channels is obtained by a greater depth of the upstream channels  11 . 
     In the embodiments shown, the end of each downstream channel  12  has a truncated cone-shaped geometry, which is designed to form a distribution channel  13 . The distribution channels  13 , e.g. numbering three, are very small, e.g. having an approximate width of 60 μm and a depth of 70 μm for a device for withdrawing a 100-μl dose under a pressure of 5 bars. 
     More precisely, the end piece  7  has a seat  24  perforated with an opening  25  on which the end  26  of the rod  16  is butt-mounted, said seat and said end each having a truncated cone-shaped geometry so as to form the distribution channels  13  and the outlet openings  14  between said geometries. 
     Furthermore, in order to further increase the speed of the liquid jets dispensed by the outlet openings  14 , it is possible to provide for the distribution channels  13  to have a cross-sectional area the transverse surface of which decreases from upstream to downstream. 
     In connection with  FIGS. 8 to 10 , the upstream  11  and downstream  12  channels are formed as concave on a rotating cylindrical bearing surface  30  of the insert  8 , said bearing surface having an outside diameter corresponding substantially to that of an inside bearing surface  31  of the end piece  7 , so as to enable the centring and formation of the channels  11 ,  12  between said bearing surfaces. 
     In this embodiment, the difference in the average transverse surface between the cross-sectional area of the upstream  11  and downstream  12  channels is obtained by providing for the downstream channels  12  to have a variable width. In particular, in the embodiment shown, the transverse surface of the upstream cross-sectional area decreases from the transverse surface of the cross-sectional area of the upstream channels  11  to the transverse surface of the cross-sectional area of the distribution channels  13 . As an alternative not shown, the depth of the upstream channels  11  can in addition be greater than that of the downstream channels  12 , so as to further increase the difference in average transverse surface between the fluid flow areas in said channels. 
     In addition, as in the embodiments of  FIGS. 1 to 7 , the bearing surface  30  has a cylindrical crown  20  around which the annular channel  21  of the distribution chamber is formed. Furthermore, the end piece  7  has a seat  24  perforated with an opening  25  on which the end of the insert  8  is butt-mounted, said seat and said end each having a truncated cone-shaped geometry so as to form the distribution channels  13  and the outlet openings  14  between said geometries.