The present invention relates to an assembly for containing and dispensing a liquid, comprising:
         a container for containing the liquid;   a liquid dispensing device arranged at the outlet of the container, comprising:   a spout through which liquid can pass out and air can come in; and   means for filtering liquid and air passing through the spout; and   a cap for closing the container.       

     The invention applies in particular, but not exclusively, to assemblies for containing and dispensing collyrium in the form of an aqueous solution, the sterility of which must be ensured. 
     The filtering means prevent the penetration of contaminating agents into the container before the membrane. 
     An object of the invention is to provide an assembly for containing and dispensing a liquid limiting the risk of dispensing contaminated liquid. 
     For this purpose, the invention proposes an assembly for containing and dispensing a liquid of the above-mentioned type, characterised in that it comprises means for encouraging the entry of air and/or the return of a residual quantity of liquid trapped in the spout after dispensing some liquid, through the filtering means, into the container. 
     According to other embodiments, the containing assembly has one or more of the following features, taken in isolation or according to all of the combinations technically possible:
         the means for increasing the entry of air and/or the return of a residual quantity of liquid comprise sealing means capable of closing in a sealed manner a space located between the spout and the partially-closed cap, the volume of which decreases as closure of the cap progresses, so as to create an overpressure in the spout downstream of the filtering means, due to the cap being closed;   the sealing means comprise a sealing lip which is integral with the spout and comes into sealed contact with an internal sealing bearing surface of the cap as the cap is closed;   the lip is integral with a part of the tubular spout having a longitudinal axis;   the lip protrudes beyond the part, said lip being inclined in relation to the longitudinal axis, radially outwards and axially towards a bottom of the cap;   the cap comprises a bottom coming into sealed contact with an outlet orifice of the spout when the cap is completely closed;   the filtering means comprise at least one microporous filtering membrane extending through a passage for the circulation of liquid and air through the spout;   the microporous filtering membrane comprises at least one liquophilic region and at least one liquophobic region;   the membrane is secured between two mutually-fixed parts of the spout;   the means for increasing the entry of air and/or the return of a residual quantity of liquid comprise a layer of porous liquophobic material, capable of being passed through by a liquid, in contact with an upstream face of the membrane; and   the means of filtration comprise one microporous filtering membrane.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the invention will emerge from the following description, given purely by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic cross-section of a containing and dispensing assembly according to the invention: 
         FIGS. 2 to 4  are partial enlarged views of the containing and dispensing assembly shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The containing and dispensing assembly  2  shown in  FIG. 1  comprises a container  4  for holding collyrium in the form of an aqueous solution, a device  6  for dispensing collyrium and a device  8  for closing the container  4 . 
     The container  4  in the embodiment illustrated is a bottle made of a plastics material, containing collyrium which has not been shown in the Figures. 
     The container  4  comprises a hollow body  10  lengthened by an upper neck  12  which extends along a vertical longitudinal axis L to an outlet orifice  13 . 
     In a conventional manner, the walls of the body  10  are resiliently deformable under the action of a transverse force so as to cause a reduction in the internal volume of the body  10 , and thus enable the expulsion of the collyrium through the neck  12 . 
     The closing device  8  comprises a cap  14  and an integral tamper-proof ring  16 . 
     Conventionally, the neck  12  has external contours such as threads, enabling connection to the cap  14 , which has complementary tapping, and the tamper-proof ring  16  is connected in translation along the axis L to a contour in the neck  12 , for example a rib  18 . 
     The dispensing device  6  comprises a spout  20  through which liquid can pass out and air can come in, accommodated partly in the neck  12  through the orifice  13 . 
     In the rest of the description, the words &lt;&lt;upstream&gt;&gt; and &lt;&lt;downstream&gt;&gt; shall be understood to relate to the direction of flow of the collyrium through the neck  12  and the spout  20  from inside the body  10  towards the outside, as illustrated by an arrow A in  FIG. 1 . 
     The spout  20  comprises two parts  22  and  24  superimposed along the axis L and defining a passage  26  for the circulation of collyrium and air, the passage passing through the spout  20  along axis L from an orifice  26   a  opening into the body  10  to an orifice  26   b  opening to the outside. 
     The lower part  24  is connected in a sealed manner to the orifice  13 . 
     The device  6  comprises a microporous membrane  28  to filter liquid and air extending across the passage  26 . 
     The membrane  28  is mounted in the spout  20  being secured between the part  22  and the part  24 . In a known manner, the membrane  28  has liquophilic regions and liquophobic regions. 
     The part  22  is arranged so as to prevent the formation of a jet of liquid so as to enable drop-by-drop dispensing of the collyrium. For this purpose, the portion  29  of the passage  26 , located downstream of the membrane  28  and defined in the part  22 , has a restriction  30 , from upstream to downstream, followed by a diffuser  31  flaring out to the orifice  26   b  located at one free end  34  of a nipple  35  of the part  22  extending so as to protrude along the axis L from a base  36  in the form of a disc of the part  22 , connected to the part  24 . 
     The part  24  comprises a tubular sleeve  37  inserted partially in a sealed manner into the neck  12 , and a circumferentially continuous annular resilient lip  38  integral with the sleeve  37 , and extending so as to protrude radially outwards from the sleeve  37 , outside the neck  12 . 
     The device  6  comprises a block  39  of porous material with open cells, for example a compressible foam, allowing the passage of liquid and possessing liquophobic properties, in contact with an upstream face  28   a  of the membrane  28 . The block  39  extends across the entire section of the passage  26 . 
     The operation of the assembly  2  is described below with reference to  FIGS. 2 to 4  illustrating the assembly  2  in different configurations. 
     As shown in  FIG. 2 , the cap  14  is screwed onto the neck  12  so as to close the container  4 . To open the container  4 , the user unscrews the cap  14 . 
     On first use, the user unscrews the cap  14  which breaks the connection between the cap  14  and the ring  16  since the latter is retained by the rib  18 . This break indicates to the user that the flask has not been previously used. On subsequent use, the connection between the cap  14  and the ring  16  is already broken, and the cap  14  is unscrewed more easily. 
     Once the cap  14  is removed ( FIG. 3 ), the user turns the container  4  upside-down, and presses the walls of the body  10  so as to expel the collyrium through the neck  12  and the device  6  by forcing its passage through the block  39  and the membrane  28 . 
     Once dispensing has been completed, the user releases the walls of the body  10 , which are brought back to their original shape by resilience. This causes a vacuum in the body  10  in relation to the outside, tending to aspirate a residual quantity of liquid present in the portion  29  and outside air through the membrane  28 . 
     The user then screws the cap  16  back ( FIG. 2 ) until it is completely closed, that is, until a bottom  40  of the cap  14  is in sealed contact with the orifice  26   b , which interrupts the re-aspiration of collyrium and the aspiration of air. 
     The aspiration of the residual quantity of liquid in the portion  29  prevents the stagnation of this liquid in the portion  29  between two uses. The aspiration of outside air enables the volume of collyrium dispensed to be replaced. 
     The aspirated liquid preferably passes through the liquophilic regions of the membrane  28  thus being filtered through it, and the aspirated air preferably passes through the liquophobic regions of the membrane  28  thus being filtered through it. 
     Due to the small porous surface offered by the membrane  28  to the air and the collyrium, the membrane  28  constitutes a brake on the re-aspiration of the residual quantity of collyrium and the aspiration of air. The resilience of the walls of the body  10  is not generally sufficient to ensure the complete re-aspiration of the residual quantity of collyrium located in the portion  29  before the complete closure of the cap  14 . 
     Consequently there is a risk that a quantity of collyrium may be trapped in the portion  29  and that contaminating agents may develop in this quantity of trapped collyrium, which would be dispensed first when next dispensing takes place. 
     Furthermore, if the body  10  does not aspirate sufficient air before the cap  14  is closed, a depression exists inside the body and it is necessary to apply a greater force on the walls of the body  10 , when next dispensing collyrium, in order to deform the body  10  sufficiently for drops of collyrium to come out of the device  6 . 
     The lip  38  and the block  39  limit these risks by increasing the entry of air and the re-aspiration of the quantity of collyrium trapped after dispensing. 
     Indeed, at the start of closing the cap  14  ( FIG. 4 ), the lip  38  comes into sealed contact at its free end with a cylindrical seating internal bearing surface  41  with an axis L of the cap  14 . The lip  38  thus closes in a sealed manner a space  42  located between the spout  20  and the bottom  40  of the partially closed cap  14 . 
     In this position, the end  34  is located at a distance from the bottom  40 , in such a way that the orifice  26   b  is still open and the passage  26  communicates with the space  42 . 
     On continuing to close the cap  14 , the lip  38  slides along the bearing surface  41  of the cap  14  which moves along the axis L in relation to the lip  38 , and the volume of the space  42  gradually diminishes. An overpressure then occurs in the space  42  and in the portion  29  in relation to the pressure existing upstream of the membrane  28 . 
     This overpressure gradually increases and pushes the quantity of collyrium trapped in the portion  29  and air through the membrane  28 . This thus encourages the re-aspiration of collyrium and the aspiration of air into the container  4  before the complete closure of the cap  14 . 
     It will be noted that the lip  38  is inclined in relation to the axis L and extends axially towards the bottom  40 . This results in an effective seal due to the fact that the overpressure in the space  42  tends to flatten the lip  38  against the bearing surface  41 . 
     Furthermore, the block  39  prevents the formation of a film of collyrium, held by capillary action on the upstream face  28   a  of the membrane  28 . Such a film would prevent the aspiration of air and also the re-aspiration of some of the trapped collyrium by obstructing the pores of the membrane  28 . 
     The block  39 , due to the fact that it is porous and liquophobic, causes the grouping or coalescence of the collyrium held on the membrane  28  into drops which are formed in the porosities of the block  39 . The block  39  thus encourages the re-aspiration of collyrium from the upstream side of the membrane  28 , as well as the entry of air into the body  10  by freeing channels for the circulation of air between the drops of collyrium, inside the block  39 . 
     The block  39  is made, for example, of a polyurethane open-cell foam (PUR), PTFE, PVC, polyester, polyether, polyethylene or polypropylene. The block  39  has, for example, a porosity of 10 to 100 PPI (pores per inch). 
     The assembly  2  thus encourages the re-aspiration of collyrium and the aspiration of air into the container  4  before it is closed. The assembly  2  thus allows the quantity of collyrium trapped downstream of the membrane, and consequently the risk of contamination, to be limited. 
     The aspiration of the quantity of trapped collyrium and the aspiration of air are particularly effective due to the fact that the force exerted by the user to close the cap  14  is used to force the entry of collyrium and the entry of air through the membrane  28 . 
     The block  39  and the lip  38  can be used independently of each other while retaining their respective advantages, to encourage the aspiration of collyrium and/or air into the container. 
     The invention thus generally relates to an assembly for containing and dispensing a liquid, comprising a container for containing the liquid, and a liquid dispensing device, comprising a spout through which liquid can pass out and air can come in, and means for filtering liquid and air passing through the spout, and a cap for closing the container, the assembly also comprising sealing means capable of closing in a sealed manner a space located between the spout and the partially closed cap, the volume of which decreases as closure of the cap progresses, so as to create an overpressure in the spout downstream of the filtering means, due to the cap being closed. 
     The invention also generally relates to an assembly for containing and dispensing a liquid, comprising a container for containing liquid, and a liquid dispensing device, comprising a spout through which liquid can pass out and air can come in, and means for filtering liquid and air passing through the spout, and a cap for closing the container, the assembly also comprising a layer of liquophobic porous material, in contact with an upstream face of the membrane. 
     The invention applies to assemblies for containing and dispensing collyrium, and more generally to assemblies for containing and dispensing a liquid, the sterility of which must be maintained.
This assembly is of the type including: a container ( 4) for containing the liquid; a liquid dispensing device ( 6), including: a spout ( 20) through which liquid can pass out and air can come in; and elements ( 28) for filtering liquid and air passing through the spout ( 20); and a cap ( 14) for closing the container ( 4). One feature of the invention is that the assembly includes elements ( 38, 41, 39) for encouraging the entrance of air and/or the return of a residual quantity of liquid trapped in the spout ( 20) after dispensing some liquid, through the filtering elements ( 28), into the container ( 4).