FR2757786A1 - LIQUID PACKAGING ASSEMBLY, ESPECIALLY A COSMETIC PRODUCT OR A MEDICINAL PRODUCT - Google Patents

Abstract

The system disclosed includes a receptacle (14) containing the liquid, which is connected to means (16) of distribution of the liquid operated by a push button (34). These means (16) of distribution comprise an air compression chamber (24) with at least one opening (72) for the admission of ambient air, as well as at least one opening (90) for the evacuation of compressed air; the volume of the compression chamber (24) varies with the operation of the push button. The liquid is contained in the receptacle (14) at a pressure of a predetermined value, which is higher than the ambient pressure, by means of air under pressure contained in the receptacle (14). The opening (90) for the evacuation of compressed air is linked to the receptacle (14) so as to substantially maintain the air pressure in the receptacle following the operation of the push button (34) to distribute an amount of liquid.

Description

 The present invention relates to a liquid packaging assembly.

 In what follows, by liquid is meant a practically incompressible more or less viscous fluid.

 The invention applies in particular to the packaging of cosmetic products or of drugs, in particular in the form of a solution such as a perfume, an eau de toilette, etc., or of an emulsion such as a milk, cream, etc ...

 Already known in the prior art a liquid packaging assembly, of the type comprising a container containing the liquid connected to liquid distribution means controlled by a pusher intended to be actuated by the user, the distribution means comprising an air compression chamber for assisting the propulsion of the liquid comprising at least one air inlet orifice at atmospheric pressure and at least one compressed air outlet orifice, the volume of the compression chamber varying by actuation of the pusher.

 A packaging assembly of this type is described for example in FR-A-2,719,789 (FR-A-94 05,755).

 In the packaging assembly described in this document, the liquid contained in the container is maintained at atmospheric pressure.

 The object of the invention is to optimize the distribution of the liquid by conditioning the latter at a pressure higher than atmospheric pressure, this without the conditioning pressure decreasing as the container becomes empty.

 To this end, the subject of the invention is a liquid conditioning assembly, of the aforementioned type, characterized in that the liquid is maintained in the container at a pressure of predetermined value, greater than atmospheric pressure, by means of air under pressure contained in the container, and in that the compressed air discharge orifice communicates with the container so as to substantially maintain the air pressure in this container after actuation of the pusher to dispense a amount of liquid.

According to the characteristics of different embodiments of the invention
- the discharge orifice is provided with a non-return valve opening when the air pressure in the compression chamber reaches that of the air in the container;
the dispensing means include means for spraying liquid, forming a nozzle, a rectilinear liquid passage conduit connecting, from upstream to downstream, the container to the nozzle, extending substantially parallel to the axial direction of movement of the pusher and integral with the movements of this pusher, a tubular drawer mounted to slide around the liquid conduit, between a first position for isolating an upstream end of the liquid conduit from the container and a second position for placing this end in communication upstream of the liquid conduit with the container, a first piston secured to the drawer, in contact with the liquid of the container, and a bracing spring for the pusher and the drawer resiliently recalling this drawer towards its first isolation position, the spring d 'bracing being dimensioned to balance the predetermined value of the pressure of the liquid exerted on the first piston;
the upstream end of the liquid conduit comprises at least one hole for placing this liquid conduit in communication with the container, opening onto the external contour of this liquid conduit, so that the bore is, respectively, closed by the internal contour of the drawer, when the latter is in its first position, and released from the drawer, when the latter is in its second position
the distribution means further comprise a second piston integral with the drawer, delimiting the compression chamber in which the air intake orifice is formed, this intake orifice being provided with a non-return valve s' opening when the air pressure in the compression chamber is lower than atmospheric pressure
the distribution means also comprise a liquid metering chamber, of variable volume under the effect of the displacement of the pusher, delimited by the first piston, the liquid conduit being placed in communication with the container by connection of the upstream end of this liquid conduit with the metering chamber, this metering chamber being provided with a closable liquid intake orifice when the volume of this metering chamber substantially reaches the volume of liquid to be metered, the sliding drawer with a clearance radial along the liquid conduit, so as to delimit between this liquid conduit and this drawer an annular air passage channel connecting, from upstream to downstream, the air compression chamber to the nozzle, the channel d air being, on the one hand, isolated from the compression chamber when the drawer is in its first position, and on the other hand, placed in communication with the compression chamber when the drawer is in its second position sition, the compressed air evacuated in the air channel allowing the suction of the liquid contained in the metering chamber by Venturi effect, the slide moving to its second position under the effect of the closure of the orifice 'admission of liquid into the dosing chamber;
- the liquid inlet orifice can be closed off by a plunger extending the upstream end of the liquid conduit
the liquid conduit and the drawer comprise complementary shoulders formed, respectively, on the external contour of the liquid conduit and on the internal contour of the drawer, intended to come into abutment against one another when the drawer is in its first position so as to isolate the air channel from the compression chamber
- the container comprises a flexible pocket containing the liquid, connected to a liquid intake duct of the distribution means, surrounded by the pressurized air contained in the container
- the liquid and the pressurized air are contained in the same volume delimited by the container
- The predetermined value of the pressure of the liquid and the air in the container is substantially equal to 2.5 bars.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the drawings in which:
- Figures 1 and 2 are views in longitudinal section of a packaging assembly according to a first embodiment of the invention, showing the pusher, respectively, in a rest position and in an intermediate active position;
- Figure 3 is a view similar to the previous figures, on an enlarged scale, in which the pusher is in a final active position
- Figure 4 is a bottom view of a connector connecting the liquid bag to the liquid intake duct
- Figure 5 is a sectional view along line 5-5 of Figure 4
- Figure 6 is an axial sectional view, on an enlarged scale, of a non-return valve for the orifice for discharging compressed air towards the container
- Figures 7 and 8 are partial views, on an enlarged scale, similar to Figures 1 and 2, of an alternative embodiment of the liquid distribution means;
- Figure 9 is a view similar to Figure 1 of a packaging assembly according to a second embodiment of the invention.

 There is shown in Figures 1 to 3 an assembly 12 for packaging liquid, according to a first embodiment of the invention.

 The liquid is constituted, for example, by a cosmetic product or by a medicament, in the form of a solution such as a perfume, an eau de toilette, etc., or of an emulsion such as a milk , a cream, etc. The liquid is more or less viscous.

 The packaging assembly 12 has a generally cylindrical shape of axis X.

 The packaging assembly 12 comprises a rigid container 14, preferably resistant to a pressure of 3 bars, surmounted by means 16 of liquid distribution. It will be noted that the container 14 can have very varied shapes other than the general cylindrical shape shown.

 The conventional elements of these distribution means 16 will be specified below, which are moreover described in detail in FR-A-2,719,789 (FR-A-94 05 755).

 Conventionally, the distribution means 16 comprise fixed 18 and mobile 20 parts.

 The fixed part 18 comprises a fixed member 22 of generally stepped tubular shape.

 The fixed member 22 successively comprises, from its widest end to its narrowest end, a first section delimiting a first air compression chamber 24, a second section delimiting a second metering chamber 26 liquid and a third section delimiting a conduit 28 for admitting liquid into the distribution means 16.

 The member 22 also includes a fixing flange 30 extending between its first and second sections. This flange 30 separates a part external to the container 14 from the member 22 (first section) from an internal part to the container 14 from the member 22 (second and third sections).

 The collar 30 is tightly fixed on the free end of a neck 32 of the container, by means of a crimping ring 36.

 The movable part 20 comprises a pusher 34 for controlling the distribution means 16 intended to be actuated by a user.

 The pusher 34 is axially movable relative to the fixed part 18, between a rest position, as shown in FIG. 1, and a final active position, as shown in FIG. 3.

 The plunger 34 is resiliently returned to its rest position by a spring 36 interposed between this plunger 34 and a fixed element 38.

 The fixed element 38 is attached to the first section of the fixed member 22 and forms, at the same time, a support seat for the spring 36 and a travel end stop of the pusher 34 in the rest position.

 Liquid spraying means, forming a nozzle 40, are arranged in the pusher 34.

For more details on the structure and operation of these means 40, reference may be made to
FR-A-2 719 789 (FR-A-94 05 755).

 The movable part 20 also comprises a rectilinear conduit 42 for the passage of liquid, provided with upstream 42A and downstream 42B ends.

 The liquid conduit 42, integral with the displacements of the pusher 34, extends substantially parallel to the direction of these displacements, preferably coaxially with the axis X '.

 The liquid conduit 42 connects, from upstream to downstream, the second metering chamber 26 to the nozzle 40.

 A tubular drawer 44 is slidably mounted, with a radial clearance, around the liquid conduit 42.

 This drawer 44 is movable between a first position for isolating the upstream end 42A of the liquid conduit with respect to the second metering chamber 26, as shown in FIGS. 1 and 2, and a second position for placing in communication. with the second metering chamber 26 of the upstream end 42A of the liquid conduit, as shown in FIG. 3.

 The axial stroke of the drawer 44 is limited, on the one hand, by complementary stops 46, 48, formed on the pusher 34 and the downstream end 44B of the drawer, close to the pusher, and on the other hand, by additional shoulders 50, 52, formed on the external contour of the liquid conduit 42 and the internal contour of the drawer 44.

 The stops 46,48 and the shoulders 50,52 are preferably delimited by frustoconical surfaces centered on the axis X.

 The downstream end 44A of the drawer, remote from the pusher 34, delimits a first piston 54 sliding in the second metering chamber 26, so as to vary the volume of this second chamber 26. The first piston 54, delimiting the chamber 26, is therefore in contact with the liquid it contains.

 A spring 56 for bracing the pusher 34 and the drawer 44 resiliently recalls this drawer towards its first isolation position.

 The upstream end 42A of the liquid conduit 42 comprises at least one radial bore 58, preferably two, intended to put this conduit 42 in communication with the second metering chamber 22.

 The holes 58 open onto the external contour of the liquid conduit 42. Thus, the holes 58 are closed by the internal contour of the drawer 44, when the latter is in its first position, and released from the drawer 44, when the latter is in its second position.

 Preferably, the internal contour of the upstream end 44A of the drawer is provided with a bead 60 allowing the tight sealing of the holes 58.

 The second metering chamber 26 is provided with a liquid intake orifice 62 delimited by the free end of a neck 64 extending the conduit 28 inside this chamber 26.

 The liquid inlet orifice 62 is closable by a plunger 66 extending the upstream end 42A of the liquid conduit.

 The plunger 66 has an end portion 66A (axially grooved) and a portion 66B (of smooth contour) for connection with the liquid conduit 42.

 When the volume of liquid in the second chamber 26 substantially reaches the volume of liquid to be dosed, the inlet orifice 62 is closed by contact with the connecting portion 66B of the plunger. Preferably, the obturation of the intake orifice 62 is sealed by a bead 68 formed on this orifice 62.

 A second piston 70, integral with the drawer 44, delimits the first compression chamber 24 and slides in the latter by actuation of the pusher 34, so as to vary its volume. This second piston 70 is provided with at least one axial orifice 72 for admission of atmospheric air, preferably several admission orifices 72 spaced circumferentially between them.

 The air intake orifices 72 are provided with a common check valve 74 opening when the air pressure in the first compression chamber 24 is lower than atmospheric pressure.

 The air which is compressed in the first chamber 24 is intended to assist the propulsion of the liquid.

 An annular air passage channel 76 is delimited by the external surface of the liquid conduit 42 and the internal surface of the drawer 44.

 The first compression chamber 24 communicates with this air channel 76 by means of at least one radial bore 78 formed in the drawer 44. As a result, the air channel 76 connects, from upstream to downstream, the first compression chamber 24 at the nozzle 40.

 When the drawer 44 is in its first position, the complementary shoulders 50, 52 are in abutment against one another, so as to isolate the air channel 76 from the first compression chamber 24.

 When the drawer is in its second position, the complementary stops 46,48 are in abutment against one another, while the complementary shoulders 50,52 are axially spaced from one another, so as to bring communication the air channel 76 with the first compression chamber 24.

 The elements of the packaging assembly will be described below, in particular the elements of the distribution means 16, which are more specific to the invention.

 The container 14 comprises a flexible pocket 80 containing the liquid, connected by a connector 82 to the conduit 28 for admitting the liquid. The pocket 80 is surrounded by pressurized air occupying the remaining volume of the container 14.

 As a variant, the pocket 80 can be connected directly to the conduit 28 for admitting liquid.

 The pressurized air makes it possible to maintain the liquid at a pressure of predetermined value, greater than atmospheric pressure, for example equal to approximately 2.5 bars.

 It will be noted that the bracing spring 56 is dimensioned to balance the predetermined value of the pressure of the liquid exerted on the first piston 54.

 Thus, one can choose for example a bracing spring 56 exerting a minimum force of 2.5 kg for an area of the first piston 54 substantially equal to 1 cm2.

 The pocket 80 is made for example of plastic or of a complex material comprising at least one layer of plastic.

 Referring more particularly to Figures 4 and 5, in which the connector 82 is shown in more detail, it can be seen that the latter comprises a female end piece 84, of circular section, force fitted on the free end of the conduit 28 ' liquid inlet, and a male endpiece 86, of flattened section, for example in the shape of a diamond, on which are welded lips 88 of the pocket 80 delimiting a drain opening of the latter.

 As a variant, the male endpiece 86 can be extended, inside the pocket 80, by a plunger tube integrally formed or attached to this endpiece 86, extending substantially to the bottom of the pocket. The dip tube makes it possible to avoid undesirable cavitation effects, in particular when the liquid contained in the bag is very viscous.

 The first compression chamber 24 is connected to the volume of the container 14 containing the air under pressure by means of at least one axial orifice 90 for discharging compressed air, preferably several orifices 90 spaced circumferentially between them.

 The discharge orifices 90 are provided with a common non-return valve 92 opening when the air pressure in the first compression chamber 24 reaches at least that of the air in the container 14.

 Referring to Figure 6, in which the non-return valve 92 is shown in more detail, it can be seen that the latter has the general shape of a bowl pierced at its center comprising a fixing flange 94 and a pierced bottom 96 connected to the rest of the bowl by a thinning 98 of its wall.

 The flange 94 of the valve is interposed and clamped between the flange 30 of the fixed member 22 and the neck 32 of the container 14.

 The drilled bottom 96 is movable elastically, substantially axially, between a position for closing the discharge orifices 90, as shown in particular in FIG. 1, and an open position for these orifices 90, as shown in the figure. 2.

 The air outlet orifices 90 are formed in the fixed member 82 and preferably open out between sealing projections 99 of this member 82 against which the valve 92 comes to bear when it is in the position of shutter.

 The compressed air discharge orifices 90 make it possible to maintain the air pressure in the container 14 following actuation of the pusher 34 to dispense a quantity of liquid, as will appear more clearly on reading the operation of the packaging assembly 12 which will be described below.

 Initially, the piston 34 is in the rest position, as shown in Figure 1 (upper position considering this figure).

 The liquid conduit 42, integral with the movements of the pusher 34, is in an initial position for opening the orifice 62 for admission into the second metering chamber 26. In fact, in this initial position, the grooved part 66A of the plunger 66 extends through the liquid inlet orifice 62 allowing the passage of liquid through this orifice 62.

 The drawer 44 is in its first position for isolating the liquid conduit 42 from the second metering chamber 26.

 To withdraw a quantity of liquid, the user presses the plunger 34 so as to move it towards an active position, downwards, by considering FIGS. 1 to 3.

 The liquid conduit 42 moves downward, together with the pusher 34.

 Similarly, the drawer 44 moves downward together with the pusher 34 and the liquid conduit 42, because the bracing spring 56 compensates for the pressure of the liquid contained in the pocket 80 and the second metering chamber 26.

 The first piston 54, sinking into the second metering chamber 26, delivers a certain amount of liquid into the pocket 80.

 The second piston 70 sinks into the first chamber 24 so as to compress the air contained therein.

 The plunger 34 then reaches an intermediate active position, as shown in FIG. 2, in which, on the one hand, the air pressure in the first compression chamber 24 becomes greater than the air pressure in the container 14, so that the valve 92 of the air discharge orifices 90 opens, and on the other hand, the portion 66B of the plunger 66 closes the orifice 62 for admitting liquid into the second chamber 26, thereby trapping a metered amount of liquid to be dispensed.

 The opening of the valve 92 allows the introduction into the container 14 of a quantity of compressed air making it possible to substantially maintain the pressure of the air in this container by compensating for the quantity of liquid withdrawn.

 Under the effect of the closure of the liquid inlet orifice 62, and of the incompressibility of this liquid in the second chamber 26, the drawer 44 moves, against the return force of the spring bracing 56, towards its second position for placing the liquid conduit 42 in communication with the second metering chamber 26, as shown in FIG. 3.

 It will be noted that in this last position of the drawer 44, the stops 46, 48 are in abutment against one another while the shoulders 50, 52 are separated from one another so as to put the channel into communication. 76 with the first compression chamber 24.

 The user continuing to exert pressure on the pusher 34, the latter continues its travel until reaching the final active position shown in FIG. 3.

 This latter position is imposed for example, by the cooperation of the free end of the neck 64 with a shoulder 100 delimiting the upstream end 42A of the liquid conduit, or else by cooperation of the widest end of the fixed member 82 with a complementary stop of the pusher 34.

During the stroke of the pusher 44 between its active intermediate and final positions, part of the compressed air in the first chamber 24 is evacuated in the air channel 76 so as to suck in by effect
Venturi (in the nozzle 40) the liquid contained in the second metering chamber 26. The quantity of liquid dosed is thus vaporized by the nozzle 40.

 It will be noted that, during the stroke of the pusher 34 between its intermediate and final active positions, the liquid conduit 42 and the drawer 44 (in its second position) move together with the pusher 34.

 When the pusher 34 is in the final active position, the pressure in the first compression chamber 24 drops, which has the effect of closing the air evacuation valve 92.

 The exhaustion of the liquid 26 contained in the second metering chamber 26 causes the drawer 44 to return to its first position for isolating the liquid conduit 42, under the effect of the bracing spring 56.

 After vaporization of the quantity of liquid dosed, the user releases the plunger 34 which returns to the rest position under the effect of the return spring 36.

 The return of the pusher 34 has the effect of opening the valve 74 for air intake and the orifice 62 for liquid intake, so that the compression chambers 24 and metering 26 are again filled with air. and liquid respectively.

 In Figures 7 and 8, there is shown an alternative embodiment of the distribution means designated by the reference 16A.

 In these figures, elements similar to those of the previous figures are designated by identical references.

 In this case, the first compression chamber 24 no longer communicates with the channel 76 (there is no drilling 78 in the drawer 44), this channel no longer having an air passage function.

 In addition, the second chamber 26 no longer has a dosing function because it permanently communicates with the volume of the pocket 80. In fact, the neck 64 delimiting the orifice 62 for admitting liquid into the second chamber 26 does not have a sealing bead.

 It will be noted that whatever the portion 66A or 66B of the plunger 66 passing through the liquid intake orifice, the latter is not blocked.

 The main differences in operation of this variant will be specified below compared to the first embodiment of the invention described above.

 Initially, the pusher 34 is in its rest position as illustrated in FIG. 7.

 When the user presses the plunger 34, the liquid conduit 42 and the drawer 44 (in its first position) moves jointly with this plunger 34, as in the first embodiment described above.

 When the air pressure in the first chamber 24 becomes higher than that of the air contained in the container 14, the discharge valve 92 opens, as shown in FIG. 8, so as to allow the introduction of pressurized air into the container 14.

 The air overpressure which allows the valve 92 to open is transmitted to the first piston 54 by means of the liquid contained in the bag 80 and in the second chamber 26.

 The effect of this overpressure is to urge the slide 44, against the return force of the bracing spring 56, towards its second position for placing the liquid in communication 42 with the second chamber 26.

 The liquid then flows through this conduit 42 to the nozzle 40 under the effect of its pressure.

 The movement of the pusher 34 continues until reaching a final active position (end of travel) similar to that shown in FIG. 3 concerning the first embodiment of the invention.

 In this end of stroke position of the plunger 34, the air contained in the first chamber 24 is no longer compressed, so that the valve 92 for discharging air closes.

 Due to the closure of this valve 92, the pressure of the liquid is no longer sufficient to oppose the return force of the bracing spring 56, so that the latter brings the drawer 44 back to its first position of isolation.

 The flow of liquid in the conduit 42 is then interrupted.

 When the user releases the plunger 34 the latter returns to its rest position and the first and second chambers 24, 26 are again filled with air and with liquid, respectively.

 FIG. 9 shows a liquid packaging assembly 12A according to a second embodiment of the invention.

 In this figure, elements similar to those of the previous figures are designated by identical references.

 In this case, the liquid and the air are contained in the same volume delimited by the container 14.

 The liquid intake conduit 28 is fitted into an extension conduit 102 extending to the bottom of the container 14.

 The distribution means 16A are of the same type as those of the variant shown in FIGS. 7 and 8.

 It will however be noted that the neck 64, extending the conduit 28 for admitting liquid into the second chamber 26 is substantially wider than this conduit 28, so as to facilitate the passage of the liquid through the intake orifice 62.

 The operation of the packaging assembly 12A is similar to that of the variant illustrated in FIGS. 7 and 8, except that the air and the liquid contained in the container 14 are no longer separated but mixed in the same. container.

 The invention has many advantages.

 In particular, it makes it possible to obtain a liquid conditioning assembly in which this liquid is kept under pressure and propelled by means of air. This avoids the use of conventional propellants not recommended or prohibited, such as perfluorinated compounds.

Claims (11)

 1. Liquid packaging assembly, of the type comprising a container (14) containing the liquid connected to means (16; 16A) of liquid distribution controlled by a pusher (34) intended to be actuated by the user, the means distribution (16; 16A) comprising a chamber (24) for compressing air for assisting the propulsion of the liquid comprising at least one orifice (72) for admission of air at atmospheric pressure and at least one orifice (90 ) for evacuating compressed air, the volume of the compression chamber (24) varying by actuation of the pusher (34), characterized in that the liquid is maintained in the container (14) at a pressure of predetermined value, greater at atmospheric pressure, by means of pressurized air contained in the container (14), and in that the orifice (90) for discharging compressed air communicates with the container (14) so as to substantially maintain the air pressure in this container as a result of actuation of the pusher (34) to dispense a quantity of liquid.  2. Packaging assembly according to claim 1, characterized in that the discharge orifice (90) is provided with a non-return valve (92) opening when the air pressure in the compression chamber (24) reaches that of the air in the container (14).  3. Packaging assembly according to claim 1 or 2, characterized in that the distribution means (16; 16A) comprise  liquid spraying means, forming a nozzle (40),  a rectilinear liquid passage conduit (42) connecting, from upstream to downstream, the container (14) to the nozzle (40), extending substantially parallel to the axial direction of movement of the pusher (34) and integral with the movements from this pusher,  a tubular drawer (44) slidably mounted around the liquid conduit (42), between a first position for isolating an upstream end (42A) of the liquid conduit with respect to the container (14) and a second positioning position communication of this upstream end (42A) of the liquid conduit with the container (14),  a first piston (54) integral with the drawer (44), in contact with the liquid in the container (14), and  a spring (56) for bracing the pusher (34) and the drawer (44) resiliently recalling this drawer towards its first isolation position, the bracing spring (56) being dimensioned to balance the predetermined value of the pressure of the liquid exerted on the first piston (54).  4. Packaging assembly according to claim 3, characterized in that the upstream end (44A) of the liquid conduit comprises at least one hole (58) for placing this liquid conduit (42) in communication with the container (14 ), opening onto the external contour of this liquid conduit (42), so that the bore (78) is, respectively, closed by the internal contour of the drawer (44), when the latter is in its first position, and released of the drawer (44), when the latter is in its second position.  5. Packaging assembly according to claim 3 or 4, characterized in that the distribution means (16; 16A) further comprise a second piston (70) integral with the drawer (44), delimiting the compression chamber (24) in which is formed the air intake port (72), this intake port (72) being provided with a non-return valve (74) opening when the air pressure in the compression (24) is less than atmospheric pressure.  6. Packaging assembly according to any one of claims 3 to 5, characterized in that the distribution means (16) also comprise  a liquid metering chamber (26) of variable volume under the effect of the displacement of the pusher (34), delimited by the first piston (54), the liquid conduit (42) being placed in communication with the container (14 ) by connection of the upstream end (42A) of this liquid conduit with the metering chamber (26), this metering chamber (26) being provided with an orifice (62) for admission of liquid which can be closed when the volume of this metering chamber substantially reaches the volume of liquid to be metered,  the drawer (44) sliding with a radial clearance along the liquid conduit (42), so as to delimit between this liquid conduit (42) and this drawer (44) an annular channel (76) for connecting air passage , from upstream to downstream, the air compression chamber (24) at the nozzle (40),  the air channel (76) being, on the one hand, isolated from the compression chamber (24) when the slide (44) is in its first position, and on the other hand, placed in communication with the compression chamber (24) when the drawer (44) is in its second position,  the compressed air discharged into the air channel (76) allowing the suction of the liquid contained in the metering chamber (26) by the Venturi effect,  the slide (44) moving to its second position under the effect of the closure of the orifice (62) for admitting liquid into the metering chamber (26).  7. A packaging assembly according to claim 6, characterized in that the orifice (62) of liquid inlet is closable by a plunger (66) extending the upstream end (42A) of the liquid conduit (42).  8. Packaging assembly according to claim 6 or 7, characterized in that the liquid conduit (42) and the drawer (44) comprise complementary shoulders (50,52) formed, respectively, on the external contour of the liquid conduit (42) and on the internal contour of the drawer (44), intended to come into abutment against each other when the drawer (44) is in its first position so as to isolate the air channel (76) by relative to the compression chamber (24).  9. Packaging assembly according to any one of the preceding claims, characterized in that the container comprises a flexible pocket (80) containing the liquid, connected to a conduit (28) for admitting liquid to the distribution means (16; 16A), surrounded by the pressurized air contained in the container (14).  10. Packaging assembly according to any one of claims 1 to 5, characterized in that the liquid and the pressurized air are contained in the same volume delimited by the container (14).  11. Packaging assembly according to any one of the preceding claims, characterized in that the predetermined value of the pressure of the liquid and of the air in the container (14) is substantially equal to 2.5 bars.