EP2616352A2

EP2616352A2 - Head for dispensing a liquid as a drip

Info

Publication number: EP2616352A2
Application number: EP11755118.4A
Authority: EP
Inventors: Alain Defemme; Fabrice Mercier
Original assignee: Laboratoires Thea SAS
Current assignee: Laboratoires Thea SAS
Priority date: 2010-07-30
Filing date: 2011-07-28
Publication date: 2013-07-24
Anticipated expiration: 2031-07-28
Also published as: DK2616352T3; US20130134186A1; SG187245A1; UA107246C2; AU2011284419B2; BR112013001352A2; PT2616352E; WO2012014050A2; CY1115527T1; TW201206405A; AU2011284419A1; AR082421A1; EA022373B1; KR20130099018A; CA2806512A1; CL2013000276A1; CN103038142A; FR2963329B1; ES2493215T3; CN103038142B

Abstract

The invention relates to a head for dispensing liquid as a drip, comprising a nozzle onto which a channel for ejecting the liquid leads, wherein air sucked in from the outside is returned through said channel in the opposite direction. In the nozzle, on the ejection channel, the drip dispensing head of the invention comprises a valve functioning as a non-return valve for the circulation of the liquid being ejected. The mobile disc of said valve is produced so as to selectively enable air to pass through the valve when the disc is bearing against the seat thereof in a position for closing the liquid ejection channel. The disc is returned to said position by negative pressure applied upstream, which tends to suck in outside air. The disc is advantageously made of a microporous material, which provides antibacterial filtering of the return air.

Description

DISPENSING HEAD OF LIQUID DROP WITH DROP

The present invention relates to the design and production of bottles that serve to drip a liquid contained in a sealed tank. It relates more particularly to bottles closed by a drop dispensing head through which the air entering the reservoir to replace a liquid fraction that has been extracted borrows the same path as the previously expelled liquid.

Flasks of this type have been described under several concrete embodiments in different prior patents of the same plaintiff company. In these bottles, a bifunctional membrane is disposed at one end of the expulsion channel, upstream of the path of the expelled liquid, to allow alternation between the passage of the expelled liquid and the passage of the incoming air. The same membrane serves as an anti-bacterial membrane, preventing the passage of impurities during the return of air into the bottle. A constant objective of the applicant is to provide bottles allowing no external contamination of the liquid contained in the tank. It is also a constant objective of the Applicant to ensure a distribution of regular drops and properly calibrated, without sagging, which contributes to a good control of the alternation between the fluid flows through a single channel, liquid flow in one direction, airflow in the opposite direction.

It is in this context that the invention aims to provide a dispensing head which is more efficient in its role dropper and in the preservation of the sterility of the liquid while being particularly simple construction and inexpensive to manufacture.

For this purpose, the invention of equipping the dispensing head with a tip pierced with a liquid expulsion channel through which is also performed the air return in the opposite direction on the path of which is disposed a valve shutter freely movable under the effect of the fluid pressures exerted on it in said channel which is mounted to operate as a non-return valve with respect to the circulation of the expelled liquid and which is designed so as to allow it to pass through selectively by the admitted air from the outside when it is applied to its seat in the position closing said channel to the circulation of the liquid.

The passage selectivity of the gas stream in the presence of an aqueous liquid is advantageously obtained by producing the shutter in the form of a porous mass of a hydrophobic material. The hydrophobic nature of the material prevents the shutter of the valve from being impregnated with liquid in the closed position of the channel remains impregnated by the liquid passing in contact with it during the liquid expulsion step, which could cause its obstruction to to the air return.

In the preferred embodiments of the invention, said shutter is made microporous in the mass and consists of a hydrophobic material whose porosity is sufficiently fine so that the shutter then provides anti-bacterial filtration of the air. crossing. It is remarkable that under the usual operating conditions of ophthalmic droplet bottles, for example, the presence of a valve thus designed, as proposed by the invention, makes it possible at the same time to control the suction of the outside air in the nozzle channel after the expulsion of a dose of liquid and to prevent that there is a risk of bacterial contamination by the penetrating air and the internal side.

According to a characteristic of the invention, the end of the nozzle comprises a droplet liquid expulsion orifice which is surrounded externally by a peripheral bead. In a manner in itself conventional, thereby ensures the stall of the drop of liquid output of the nozzle, allowing a repeatable calibration of successive drops.

According to secondary features of the invention, the nozzle comprises a cavity formed in the path of the expulsion channel in which the shutter is housed, at least in part. The shutter is thus retained in the dispensing head during its movements between the open position of the valve for the passage of the liquid being expelled and closed position, allowing only the air sucked back. In the preferred embodiments of the dispensing head according to the invention, the valve is of the type of a ball valve, the ball valve being then, in its entirety, freely movable within the receiving cavity. The concept of ball preferably refers to a shutter spherical shape, which can move freely in the cavity and move isotropically in all directions within the cavity, but the spherical shape is not strictly limiting in the implementation of the invention, and oval or oblong forms in particular may also be suitable. In other embodiments, the shutter may have a pion-shaped shape with two bulging parts on either side of a neck so as to be partly lodged in the cavity and partly outside, beyond the terminal orifice of the expulsion channel, being guided axially in its movements at this orifice. According to a secondary characteristic of the invention, centripetal channels are hollowed out superficially in the walls of the receiving cavity of the shutter, all around the expulsion orifice. Their role is to pass the liquid around the shutter in the open valve position, ensuring the distribution of the liquid flow for the formation of a drop to be delivered. They are provided away from the surface forming the seat on which the shutter is applied when the valve is in the closed position, so as not to interfere with the role of the valve vis-à-vis the air flow, which consists to prohibit the passage to any return of outside air other than through the shutter. The solution proposed by the invention is advantageously combined with the presence of an antibacterial filter membrane interposed at the base of the nozzle across the dispensing head. Such a membrane is conventionally used in the ophthalmic drop bottles of the Applicant to prevent contamination of the liquid contained in reserve in the flask by bacteria from outside. The valve proposed here, in the case of an obturator filtering antibacterial, performs a filtration complementary to the air for the one that enters the part of the dispensing head which is located in the dropper tip, in downstream of the filter membrane (the downstream side being defined with respect to the direction of circulation of the liquid at the expulsion). The flap contributes on the other hand to the alternation between liquid flow and air flow provided by a diaphragm mounted upstream, at the base of the nozzle, across the passage of the incoming air and the expelled liquid, when it is made in part hydrophilic and partly hydrophobic, as it is in itself conventional for this purpose. Thus, the dispensing head according to the invention makes it possible to have a valve which ensures both this alternation of the flows and the anti-bacterial filtration on the path of the re-entering air after the expulsion of the liquid, in a manner complementary to the same functions implemented pa anti-bacterial membrane made partially hydrophilic and partially hydrophobic.

As part of the implementation of the features that are set forth herein, the invention also relates to a drip liquid distribution head having a flux regulator pad housed in the body of a head mounting insert dispenser in the neck of a bottle and preceding the dropper tip on the expulsion path of the liquid, and a bottle for packaging a liquid to be dispensed drop by drop, comprising such a dispensing head and a liquid storage tank whose peripheral walls are elastically reversible deformation to cause the expulsion of liquid from the tank and allow the suction of outside air to replace the liquid expelled from the tank. As has been explained in the prior art documents filed by the applicant company, the flux regulator buffer not only acts to regulate the flow of liquid pushed out of the reservoir during the compression of the deformable walls, but it also effect on the airflow during the return of the walls to their original state concerning the balancing of the pressures between upstream side and downstream side. Therefore, its presence also contributes to the proper functioning of the valve provided by the invention, when the shutter moves from the closed position to the open position under the effect of the pressure of the liquid pushed out of the bottle and when it is moves from the open position to the closed position under the effect of the depression created upstream, in the bottle, which sucks the outside air.

It is observed that in such a bottle, the alternation between the expulsion of the liquid to be dispensed and the return of air and the purification of the air entering the dispensing head to the bottle are carried out on several levels, between the microporous buffer, the flapper with sound shutter driven into the mouthpiece by the fact of the pressure effects exerted on it in the axial direction of the channel, and the intermediate bifunctional membrane between them.

Other characteristics and advantages of the invention will emerge more precisely from the description which follows, a description illustrated by the following figures:

- Figure 1 which shows in axial section a bottle according to the invention;

FIG 1A which exploded the different components of the bottle of Figure 1, seen in axial section;

FIG 2 which represents in axial section the drop delivery nozzle of the bottle of Figure 1;

FIG 3 is a sectional view along A-A of the tip of Figure 2, making particularly visible its internal channels;

and FIG. 4 which represents an alternative embodiment of the end piece, in a view similar to that of FIG. 2, with the associated cap represented in dotted lines.

A bottle for packaging a liquid to be dispensed drop by drop is illustrated in FIGS. 1 and 1A in the form of a bottle intended more particularly for packaging an eye drop. The composition of the latter may advantageously meet a formula devoid of preservative, because of the quality of the antibacterial preservation provided according to the invention.

This bottle according to the invention comprises a receptacle 2 providing inside a liquid storage tank 8, and a liquid dispensing head 4 mounted in a neck 10 of the container at one end of said tank by closing the latter. A removable cap 6 is provided to cover the dispensing head when the user does not use the bottle. The neck 10 has on its outer surface a thread adapted to cooperate with a thread of the removable cap to allow the closure of the bottle. The reservoir 8 comprises a cylindrical peripheral wall with reversible elastic deformation. This allows a distribution of the liquid from a manual compression exerted on the wall by the user, the wall returning spontaneously to its original shape by admission of air after this compression. The return of air to compensate for each drop of liquid expelled is effected in the reverse path of this expulsion through the dispensing head mounted in the neck of the bottle, passing in particular a same central channel for the circulation of air and the circulation of liquid. No other air intake is possible; in particular, there is no pressure equalizing hole through the outer wall of the bottle opening into the liquid reservoir.

The drip liquid dispensing head comprises a part internal to the bottle, formed by an insert 12 which is disposed inside the neck 10, and an external part forming a drop delivery nozzle 14 (or tip drops). A flux regulating pad 16 is interposed across the central duct passing through the dispensing head, into the hollow body of the insert 12, while an antibacterial filter membrane 18, also interposed across the central duct, is disposed to the base of the mouthpiece; it is enclosed at its periphery between the insert and the tip. It is understood that the insert 12 is a mounting bracket for the buffer 16 and the membrane 18, and that it is itself fixed and sealed mounting on the bottle.

On the upper edge of the insert is formed a peripheral ring 17 which acts as a translation stop stop during assembly by force-fitting the insert inside the neck of the bottle. This is made possible by the slight capacity of elastic deformation of the material constituting the insert. The tightness at the interlocking connection is completed by the presence of circular ring rods 15, called gadroons, formed at the periphery of the insert. These rods are preferably integral with the insert, in the same step of manufacturing by molding. They ensure the sealing of contact with the inner wall of the neck and they ensure the tight fitting of the insert mentioned above. The insert has a generally cylindrical shape and houses in its inner recess the flux regulating pad 16, which is shaped cylindrical wedding that of the recess. The junction between the two parts is tight as explained above, both with respect to the liquid and with respect to the air.

The pad 16 is made of a microporous material based on a hydrophobic material, which is in particular in the form of a felt having a polyethylene frame. As a result, it is not impregnated by the liquid that passes through it and it does not tend to retain within it traces of liquid that would clog its pores by closing them to the subsequent air circulation. Its regulating role of flow comes from its microporous structure. It is exercised in the direction of liquid circulation to prevent the passage of the liquid from the tank to the nozzle in the absence of sufficient compression of the container wall, when manually pressed on the flexible wall of the tank to force the liquid through the buffer. In the direction of the gas circulation it causes a pressure drop in the path of the intake of air sucked by the same way, which slows the balancing of the pressures between the inside and the outside of the bottle when, the compression the reservoir having ceased, the tank swells by spontaneous return of its walls to the original shape, while the removable cap is not yet in place in closing the dropper tip. In one example of such a flux regulator pad, in itself conventional, its structure is that of a felted yarn of fibers, under a density corresponding to a pore diameter of the order of 50 microns.

The antibacterial filter membrane 18, having a bifunctional capacity for a hydrophilic part and a hydrophobic portion, is disposed downstream of the pad and upstream of the nozzle, across the passage of the air entering from the outside through the mouthpiece. and the passage of liquid exiting the reservoir to the nozzle. The bifunctional nature of the membrane makes it possible to ensure alternating passage of the liquid in one direction and air in the other direction. The same membrane serves as an anti-bacterial membrane by preventing the passage of impurities during the return of air into the vial. This membrane is fixed on its periphery by thermal welding between a peripheral ring of the base of the tip and a cooperating surface of the insert. The membrane may be made of a polymeric material, based for example on polyether sulfone, which is normally hydrophilic but rendered hydrophobic on a only part of the surface of the membrane. It has a mesh size of the order of 0.1 to 0.2 micrometers.

The cap 6 is adapted to be screwed in a known manner on the neck of the bottle, and it closes in this screwed position the end of the expulsion channel. By thus closing the inside of the dispensing head to the air outside the bottle, the introduction of the cap also makes it possible to prevent drying of the dispensing head which could cause a sticking phenomenon of the valve.

The cap 6 is formed of a hollow cylinder closed at one end and having inside the cylinder a central pin 61 projecting from the radial end wall 62. The cap further comprises two concentric chimneys 63 and 64 between the central pin and the peripheral side wall 65. The central pin is intended to cooperate with the terminal orifice of the expulsion channel of the nozzle to close it while the chimneys 63 and 64 are intended to bear against the surfaces external of this nozzle, one bearing radially on the periphery of its slender axial portion, the other bearing axially on the transverse face of its base.

We will now describe in detail the dropper tip of the dispensing head, based in particular on Figures 2 and 3.

The tip 14 is pierced at its center with an axial duct 22 which extends from its base 23 to an expulsion orifice 24 of the liquid, situated at the end of its slender axial portion, in the end wall. upper 25, when we consider the bottle placed vertically. The base of the tip is hollowed on its inner face with grooves 3 which facilitate the drainage of the liquid from the entire surface of the membrane 18 to the expulsion orifice.

A peripheral bead 29 is formed at the end of the tip, projecting from the upper end wall outwardly of the tip, around the expulsion orifice. When liquid is expelled through the orifice, the peripheral bead is used to promote the stall of the drop, more particularly to repeatedly obtain a calibrated drop at each delivery. A central core 30 extends inside the body of the nozzle from the base 23 towards the upper end wall. This core has a shape complementary to that of the axial duct in which it is housed, that is to say a circular section, generally cylindrical or frustoconical. Its outer diameter is adjusted to the inner diameter of the tip body, where it is forced back, so that there can not circulate here air or liquid around him. It is against pierced along its central axis to form the expulsion channel 32 through which the liquid is delivered drop by drop in operation. The axial dimension of the core is smaller than the axial dimension of the central conduit, so that the upper end surface of the core extends away from the upper end wall of the hub when the core is in place in the tip.

A spherical cavity 33 is then formed, delimited by the inner surface of the walls of the tip body and by that of its inner core at its upper end. The cavity is arranged on the path of the expulsion channel 32, close to the expulsion orifice 24. The cavity opens upstream on the central channel and downstream on the expulsion orifice, so that the liquid expelled from the bottle by the expulsion channel is passed through this cavity, as well as the air brought to enter the bottle in compensation.

The tip is equipped with a ball valve 28 which is constituted at the end of the expulsion channel and which has a ball valve freely movable in the cavity 33. It is observed that the upper end surface of the core 30 has a spherical profile adapted to form a valve seat 36, adapted to cooperate with a spherical ball constituting the movable shutter of the valve, by sealing contact on an annular zone around the mouth of the channel.

In the embodiment of the invention illustrated in FIGS. 1 and 2, the shutter of the ball valve has the shape of a real ball of spherical shape which is entirely lodged in the cavity. This ball is movable in the cavity between two end positions, axially opposite, a first position or closed position of closure in which the ball rests on the valve seat formed by the end surface of the core, the upstream side of the cavity 33, and a second position or open dispensing position in which the ball is in abutment against the upper end wall of the nozzle, the downstream side of the cavity.

The shutter of the valve is made of a porous material of hydrophobic nature. The pore diameter here is less than 0.2 μ ^η τι, allowing anti-bacterial filtration of the air that is passed through the shutter. For this purpose, it may also be provided, in a variant, to impart to the valve an anti-bacterial treatment by the use of a polymeric material with intrinsic bactericidal effect, as may be especially polymeric materials incorporating silver ions. The ball is adapted to rest on the valve seat 36 formed at the bottom of the cavity (the bottle being considered placed vertically) when no pressure is exerted on the walls with reversible elastic deformation of the container. The valve seat has a curved radius profile adapted to that of the ball so that there is no air passage possible between the ball and the upper end surface of the core when the ball is in support on his seat. This complementarity of the spherical shapes is particularly interesting in the present case of a ball shutter freely movable in any direction in the cavity, without any other solicitation than the effects of fluid pressure. When the valve is in its closed position, the ball resting on its seat, the liquid expulsion circuit is closed. Manual pressure on the deformable walls of the container causes the ball to move away from its seat under the pressure of the liquid pushed out of the bottle, which allows the exit of this liquid pushed bypassing the shutter to the orifice expulsion. It should be noted that a simple inversion of the bottle can not cause this displacement of the ball, because of the presence of the flux regulating buffer.

After the liquid distribution, the release of the stress on the deformable walls of the container there is a vacuum that tends to suck the outside air while causing the closure of the valve, and the ball taking up place on his seat, the traces of undispensed liquid are recalled inside the bottle and the outside air is sucked through the shutter of the closed valve. It is observed that the excess volume of liquid to be recalled inside the bottle is tiny. When all the liquid has passed under the ball, the seal is then completely ensured since the ball can rest entirely against the seat. The porous character of the valve ensures, he, a passage of air through the valve in all circumstances, and in particular when the valve is in the closed position, that is to say when there is more residual fluid between the seat and the ball valve.

In the closed position, when the liquid distribution is finished, there is thus a passage of filtered air through the ball to allow the tank to be filled with air in compensation for the liquid expelled, after the passage of the liquid. in excess to the tank. It is important on the one hand to allow the passage of air inwards after dispensing so that the bottle returns to its original shape and allows the subsequent correct distribution of liquid, and on the other hand to preserve the sterility of the product still present inside the container.

By moving from open position to closed position and vice versa, the valve already ensures by itself, at the level of the dropper tip, the alternation between liquid flow and air flow. The same alternation is ensured by the bifunctional membrane. The valve also has the effect, by the fineness of the chosen porosity, to block the bacteria present in the outside air while allowing the filtered air to pass, just as the bifunctional membrane is made to do further.

As just described, the ball is adapted to move from a closed position against the seat of the valve to an open position of the liquid expulsion conduit in which the ball abuts against the wall of the valve. upper end of the tip against the expulsion port. The size of the cavity 33 and the dimension of the ball are determined so that the displacement of the ball from one position to the other remains low, just sufficient to perform the valve function, in a compromise advantageous with the need for a quick return of the ball on its seat to close the way to the outside air.

Centripetal channels 38 are formed by grooves cut in the wall delimiting the cavity, inside the tip. They are present in the upper half of this cavity, that is to say the half near the expulsion orifice, and they open on the expulsion orifice. In this way, these channels are intended to ensure distribution of the liquid outlet flow all around the valve ball when the ball is positioned in front of the orifice. Due to their small section and the effects of capillarity, they hardly allow air to enter prematurely after being filled with liquid. As illustrated in Figure 3, these channels are angularly distributed over the entire cavity.

The constituent elements of the dispensing head are generally made of a plastic material compatible with the application for the preservation of an ophthalmic solution. They are each made of polymer of the family of polyethylenes.

Advantageously, the tip incorporates in the mass a polymer carrying ions with bactericidal effect. The latter is chosen to be compatible with the conventional plastic material of the tip. For this reason alone, it is preferably based on polyethylene. It is commercially available in the form of powder or granules or beads, ready to be incorporated into the molding composition of the tip. The bactericidal agent is preferably composed of silver ions, which are carried by the macromolecules of polymer.

The tip according to the invention is manufactured according to a conventional molding process. At the end of the molding, the bactericidal agent is present throughout the mass of the tip, and in particular both on its external surface may come into contact with the eyes or the hands of the user, as on its internal surface delimiting its central channel.

The central core of the tip is made by a molding process, from the same base material, especially polyethylene, that the body of the tip that surrounds it. Since the valve disposed downstream of the core blocks the return of liquid and provides anti-bacterial filtration on the air return in compensation, it is conceivable not to perform an antibacterial treatment of the core. However, such a treatment can be performed and the nucleus then advantageously comprises a bactericidal agent different from that contained in the body to have effect on the outer surface of the tip. This bactericidal agent is, for example, triclosan, a compound which has a broad anti-bacterial spectrum. We will now describe the mounting of the dispensing head according to the invention.

The ball is mounted inside the nozzle, inserting it by the base and making it go up through the axial duct. The ball is brought into abutment against the inner face of the upper end wall of the tip. The core is then inserted into the conduit by force engagement. An annular groove (not shown) formed at the base of the core, comes opposite a boss (also not shown) complementary shape to the shape of the groove. The two elements cooperate by an elastic latching effect, to ensure a solid retention of the core inside the channel.

The cavity of the ball valve is thus formed, delimited by the upper end wall and the side walls of the nozzle and the end surface of the core. The ball is trapped in the cavity, freely movable between the two axially opposite end positions in the path of the central channel where it abuts against the wall of the cavity.

Finally, the membrane is positioned on the base of the nozzle and the membrane is welded to its periphery, before welding the assembly thus formed to the insert.

The vial thus formed is used for the drip distribution of a liquid. The user removes the cap and then presses the walls of the tank to let out the drops of liquid. After use, the cap is put back in place. As is apparent from Figure 1, the cap contributes by its central pin 61 which closes the expulsion port to bring and maintain the shutter of the valve against its seat.

We will now describe an alternative embodiment, illustrated in Figure 4, wherein a dispensing nozzle 1 14 is substantially similar to the tip 14 described above except that the shape of the valve 128 differs. In this variant, the ball of the valve is replaced by a pin 40 with a head 42 adapted to be housed in the cavity and a frustoconical portion 44 which cooperates with the outer face of the expulsion orifice. It will be understood that in this variant embodiment, the expulsion orifice has a section different from the section of the orifice of the embodiment described above, with the walls defining this orifice which are bevelled and which are thus adapted to cooperate with the frustoconical portion of the valve.

The mounting of the valve 128 (more accurately its movable shutter) is by press fitting through the expulsion orifice until the head is found in the cavity. In fact, advantageously, no core is provided in the mouthpiece, as has been shown in FIG. 4, the expulsion channel being formed directly by a bore in the center of the mouthpiece. The cavity 33 is thus formed solely by internal walls of the nozzle, without the presence of a core. For the sake of ease of realization, it is possible to provide a cut-off end in two parts, each part comprising a hollow forming the cavity when

75 the parts are assembled against each other. It is also possible to provide two parts to be assembled one on the other, with an upper part which includes the seat and the valve and a lower part which forms the central channel.

In use, the frustoconical portion of the valve coming out of the nozzle 0 is adapted to close the expulsion orifice from the outside of the nozzle when the excess liquid and then the air are recalled inside of the bottle. It is here the frustoconical portion 44 and the upper end wall of the nozzle 125 which respectively form the shutter and the seat of the valve. The seal is made between the frustoconical portion and the upper end wall of the nozzle, the outer side of the nozzle, unlike the previously described embodiment where the seal was on a seat inside the cavity .

Since the head has only an abutment role, its shape and dimension are less important than in the embodiment previously described. The ovoid shape of the head shown in FIG. 4 makes it easier to press fit into the expulsion orifice, the diameter being sufficient to form a stop against the wall when the head is in the cavity and the head being flattened. to reduce the weight of the whole. It is observed here that the shutter of the valve is linearly guided in its 5 displacements, this to its crossing of the wall of the nozzle at the level of the expulsion orifice. The shutter of the valve moves as before following pressure effects only, an overpressure on the upstream side to eject liquid tending to push it out of its seat, and conversely, the appearance of a suction vacuum l Outside air tends to press the valve into sealed contact against its seat, forcing the air drawn in from outside to pass through the shutter. In this variant, the closed position is obtained by the contact of the frustoconical portion 44 of the movable shutter on the bevelled walls 126 defining the orifice while the dispensing position is obtained by the contact of the head against the face. internal of the upper end wall of the nozzle, which forms a stop means to move the valve shutter.

The valve is also made of a hydrophobic porous material. As before, the porosity fineness is chosen to ensure the bacterial filtration of the outside air entering the bottle, while the hydrophobic nature of the material makes it possible to ensure that the valve in the closed position of the channel can be traversed by the return air flow.

The tip also differs in that no bead is provided for the stall and the calibration of the drop. This is the valve shutter in its outer frustoconical portion that provides this function.

In addition, the presence of the valve in the expulsion orifice implies a different form of cap, shown in dashed lines in FIG. 4. The cap does not include a central pin. However, as before, the pressure of the inner chimney against the outer wall of the nozzle on its periphery tends to push the air sucked inwardly of the bottle and to press the shutter against its seat.

The foregoing description clearly explains how the invention makes it possible to achieve the objectives it has set for itself, thanks to the valve made according to the invention for managing the alternation between the passage of the liquid expelled from the bottle and the passage of the liquid. air sucked by the same way in compensation for the liquid consumed. The microporous structure of the solid material constituting the shutter of the valve and its hydrophobic nature in the mass have the consequence that it is selectively allowed to pass through the air while it is impermeable to water. When it is pushed outward by the liquid being expelled and it abuts on the walls of the cavity which holds it, the liquid can not cross but can circulate around him and pass through the capillary section passages which are provided for this purpose to the terminal orifice. When conversely a depression in the bottle attracts the shutter by sucking air from outside, it abuts at the bottom of its cavity, and in this closed valve position, it is in sealing contact on the wall of the cavity all around the outlet of the axial channel of the nozzle. Therefore, not passing around but through the shutter, only the outside air can nevertheless enter the bottle to occupy the volume left vacant by the liquid that has been extracted.

However, the embodiments which have been described in detail above are not limiting of the invention. In any event, the invention can not be limited to the embodiments specifically described in this document, and extends in particular to all equivalent means and to any technically operating combination of these means.

Claims

A drip-liquid dispensing head having a nozzle (14; 114) pierced with a liquid expulsion channel (32) through which the return air is also effected, characterized in that it comprises, at the end of the nozzle, a valve operating as a non-return valve by closing said channel with respect to the circulation of liquid, said valve comprising a shutter (34; 40) which is retained in a cavity receiver (33) formed in the path of said channel and which is movable relative to a seat (36; 126) against which it is applied in the closed position of the valve under the sole effect of the pressure differences exerted on it, said shutter being made to be selectively traversed by air when applied against said seat.

2. Drop dispensing head according to claim 1, characterized in that the shutter of the valve (34; 40) is made of a porous material of fineness such that it constitutes an anti-bacterial filter.

3. Dispensing head according to claim 1 or 2, characterized in that the shutter of the valve (34; 40) is made of a hydrophobic material.

4. Dispensing head according to one of the preceding claims, characterized in that the end of the nozzle comprises a drip orifice (24) of liquid which is surrounded by a peripheral bead (29).

5. Dispensing head according to one of the preceding claims, characterized in that the shutter of the valve (34; 40) is adapted to move axially in said cavity (33).

6. Dispensing head according to one of the preceding claims, characterized in that the shutter of the valve has a spherical ball shape (34), which is fully housed in said cavity (33) where it is freely movable in all directions .

7. Dispensing head according to one of the preceding claims, characterized in that the shutter of the valve has a pin-like shape (40) having a head (42) which is adapted to be housed in the cavity (33) and a frustoconical portion (44) extending out of the cavity and cooperating with the tip end.

8. Dispensing head according to one of the preceding claims, characterized in that centripetal grooves (38) are formed in the walls of the cavity (33) to form capillary channels delivering passage to the liquid as the shutter abuts on the wall of the cavity in the open position of the valve.

9. Dispensing head according to one of the preceding claims, characterized in that a bifunctional membrane (18), which is partly hydrophilic and partly hydrophobic, is mounted at the base of the tip (14; 1 14). said membrane preferably being anti-bacterial filtering effect for outdoor air.

10. Dispensing head according to one of the preceding claims, characterized in that the head comprises a flux regulator pad (16) housed in the body of an insert (12) preceding the tip (14) on the path d expulsion of the liquid, said buffer being advantageously made of a hydrophobic material.

1 1. Dispensing head according to one of the preceding claims, characterized in that the shutter retaining cavity is formed between the free end of the pierced end of an orifice for expulsion of the drops and a central core occupying the inside the body of the tip which is pierced axially of the liquid expulsion channel.

12. Packaging bottle of a liquid to be dispensed drop by drop, characterized in that it comprises a dispensing head according to claim 10 and a liquid storage tank (2) whose peripheral walls are elastically reversible deformation for promote the expulsion of liquid from the tank and allow the return of air in replacing the expelled liquid in this tank, the buffer (16) providing a regulation of the liquid flow expelled from the reservoir during the compression of the deformable walls and creating a pressure drop on the air intake in balancing the pressures between the interior and the outside of the bottle.