FR2645509A1 - Assembly for dispensing a liquid or a milk in a small drop - Google Patents

Abstract

With a view to releasing a relatively liquid product in the form of a divided drop of the order of ten microlitres, the present invention utilises a known metering pump. Provision is however made to integrate it with an original dispensing assembly. The pump body is in fact made integral with a container 1 having an open side 18. The end-piece/pusher 2 is extended, for its part, into a covering 27 adapted to receive the container 1 whilst leaving its open side 18 accessible. The manufacturer of the product to be released need then only fill the container 1 and close it using, among other things, a crimped cap 7. The dispensing assembly can then be delivered to the final user, for example a patient who requires eye treatment by applying a layer of product in the tear duct without excess wastage.

Description

 The present invention relates to an assembly containing a reserve of a product whose consistency ranges from that of water to that of milk and making it possible to distribute this product drop by drop. Each drop also corresponds to a small volume of the order of ten microliters. Finally, it is emitted with a pressure slightly higher than atmospheric pressure so that an effect of dividing the drop can be obtained.

 A set of this kind is already known. A description will be found in French patent application no. 88-16867 filed on December 20, 1988. n uses a metering pump of a very specific type although conventionally composed by a pump body comprising a pump chamber, a piston sliding in the chamber and extended outside of the latter by a rod pierced with an emission channel which can communicate with the chamber as well as a nozzle made integral with the rod and having an orifice emission in the extension of the rod channel.

 Its originality resides first of all in the inlet valve of the chamber which is constituted by the direct collaboration of the enclosure of the chamber in the form of a sealing lip with the piston engaging or emerging from the chamber according to the case. This arrangement allows the distribution of a drop, the volume of which, determined by the capacity of the chamber, is very small. Furthermore, the piston is returned to its rest position, inlet valve closed, by elastic means arranged between the pump body and the nozzle. This avoids inter alia any contact of these elastic means with the liquid to be dispensed. Finally, an outlet valve is placed between the end of the emitting channel of the rod and the emitting orifice of the nozzle in order to guarantee a slight precompression of the drop dispensed.

 In the prior art, this metering pump is however associated with a bottle on which the pump body is mounted in leaktight manner. In addition, a gripping unit is provided to facilitate actuation of the dosing pump, the size of which, as the volume of the drops to be emitted, is very small. This results in a distribution assembly, the assembly of which at the product manufacturer requires several operations, for example: I / filling the bottle, 2 / crimping the pump body on the filled bottle, 3 / fitting the bottle with its pump in the grip box.

When it comes to assembling millions of distribution sets in this way, the number of these operations quickly becomes economically constraining. So it is interesting to get rid of even one of them.

 This is how the present invention aims to integrate the metering pump of the prior art described above within a distribution assembly whose filling and final packaging require at most two operations.

To this end is designed an assembly for distributing a liquid or milk-like product per drop of small volume comprising: - a pump body which encloses a pump chamber having a bottomless enclosure, - a piston adapted to engage and to slide tightly in said enclosure, a
rod passing through said pump body being integral with said piston and being pierced with a
central canal communicating with a conduit which opens laterally to the root of
said rod under said piston, - a nozzle adapted to be tightly secured to said rod and having an orifice
emission, - elastic means arranged between said pump body and said nozzle for
oppose the disengagement of said piston from said enclosure, - as well as an outlet valve disposed between said emission channel of said rod and said
orifice of emission of said nozzle, oractérise in that: Said pump body extends around said enclosure of said chamber
pump in an open container on the side opposite said pump body to be filled
of said product; in that 2 / said end piece extends around said rod of said piston in an envelope adapted to
receiving said container with a clearance compatible with a relative sliding of said
container and said envelope, said envelope being further provided with means
abutment to limit said relative sliding; and in that 3 / said open side of said container is closed by sufficiently closing means
solid to receive pressure from a finger of a user while said
envelope has gripping means for applying two other fingers
said user who can. compress said elastic means in order to
induce remission of a drop of said product through said emission orifice.

 In order to ensure sealing of the pump chamber, in particular at the point where the rod passes through the pump body, said container is made of a plastic material with a flexibility comparable to that of low density polyethylene, said pump body then comprising a thin sealing lip oriented towards the inside of said chamber to apply to said rod passing through said pump body, said rod also having an annular cutout in which opens said lateral duct. Thus the fine lip of the pump body is kept folded against the piston when the distribution assembly is at rest. As a result of the aging of the plastic material which is accompanied by a creep of the lip, tends rather to it give a shape guaranteeing, during actuation of the pump, an increasingly effective seal. The annular cutout of the rod also prevents the thin lip from catching within the lateral mouth of the duct.

 Advantageously, said container widens from said enclosure in a truncated cone so that there is a minimum internal volume between said container and said enclosure. From the soffe the amount of product remaining after the container has been emptied by the pump is as small as possible.

 According to one embodiment of the present dispensing assembly, said means for closing said container consist of a capsule which is crimped after said container is filled with product for half of its capacity. According to another embodiment, said means for closing said container consist of a snap-on cover, an air vent being provided between said open side of said container and said cover and a scraper piston being also sealingly engaged in said container to separate said product from ambient air regardless of the filling rate of said container. In this latest version of the present invention, the dispensing assembly can be actuated regardless of its orientation relative to the vertical.

 Preferably, said container protrudes from said envelope when said elastic means are at rest, said container comprising tear-off tamper-evident tabs providing a stop for said envelope to prevent said relative sliding.

 Advantageously, said stop means consist of several partitions integral with said envelope. Said elastic means then consist for example of a helical spring surrounding said rod, said spring being held externally by said partitions.

 Finally, it may be advantageous for said emission orifice to be part of a nozzle integrated into said nozzle.

 Other characteristics and advantages of the invention will appear in the light of the following description of two embodiments given by way of nonlimiting examples. These are further illustrated by the accompanying drawings which represent on a scale approximately three and a half times larger than reality: - in Figure 1, an axial section of a first embodiment of this set of dispensing in its rest position, - in Figure 2, an axial section of the embodiment of Figure 1, but this time when a user compresses the present set to the maximum, - in Figure 3, an axial section d 'a second embodiment of the present assembly in its rest position.

 The dispensing assembly according to the present invention which is shown in Figure 1 firstly consists of a container 1 advantageously made of a relatively flexible plastic material such as low density polyethylene. This container 1 admits for example the shape of a right cylinder of a priori arbitrary height. At one of its ends, the cylinder in question is open, its edge 18 preferably having an annular relief 16. By means of a notch 17 formed on the outer surface of the container near the edge 18, a capsule 7 (made of deformable metal for example) can thus be crimped around the edge 18 in order to seal the open end of the container 1 .

 At its other end, the container 1 preferably narrows along a truncated cone 15. At the bottom of the truncated cone 15, a thick annular lip projects towards the interior of the container. This in fact constitutes the enclosure 11 of a pump chamber according to a known characteristic of the dosing pumps mentioned at the start. However, it is now integral with the container 1 which therefore incorporates the pump body. Concentrically to the enclosure 11 is formed a hole passing right through the bottom of the truncated cone 15. The wall 12 of this hole finds advantage in presenting, on the inner side of the container 1, a very thin lip 13 of sealing and, on the outside, a sealing sleeve 14.

 In fact, according to the known structure of the dosing pumps mentioned above, a rod 32 has passed through the hole in order to slide therein in a perfectly sealed manner.

The rod 32 is also secured to a piston 31 of slightly larger section in order to circulate in the enclosure 11 while its sliding surface remains in sealed contact with the enclosure 11. The enclosure 11 is, according to a principle known, rather flared at its root on the bottom of the truncated cone 15. This results in a reduction in the contact surface of the piston 31 on the enclosure 11 which is more favorable to good sealing.

 The rod 32 is also pierced with an axial channel 34. The latter communicates with a conduit 35 opening laterally to the surface of the rod 32 just at the base of the piston 31. A small annular cutout 36 is made around the rod 32 at the mouth of the conduit 35 and over a height of barely larger than this mouth. Thus, the thin sealing lip 13 disposed at the wall 12 of the hole in the bottom of the container 1 does not run the risk of being trapped in the mouth of the conduit 35 when the rod 32 comes and goes.

 In accordance with the anterior binder dosing pump, the free end of the rod 32 is adapted to take place within a hollow tube 21 secured to a nozzle 2.

For this purpose, the rod 32 has for example a series of asperities 33 on its lateral surface. They then collaborate with a complementary series of grooves 22 on the internal surface of the tube 21 as soon as the rod 32 is forcibly engaged in the free end of this tube 21. At its other end, there is a bottom pierced with a orifice 24.

Thus, between this bottom and the rod 32, is formed a chamber in which is housed in known manner a small part acting as a valve 5. This part, advantageously symmetrical to facilitate its positioning, for example consists of two hemispheres between which extend one or more flexible balusters. A hemisphere is then arranged so that it closes the channel 34 of the rod 32 and the other, the orifice 24 of the end piece 2.

 As shown in FIG. 1, the orifice 24 may correspond to a simple perforation of the bottom of the hollow tube 21 of the end piece 2 with, on the inside, ribs 23 arranged radially and, on the outside, a bevel 25 annular arranged recessed from the outer surface of the nozzle. The interest of these elements will appear further on in the description of the operation of the distribution assembly. For the time being, we will limit ourselves to indicating that various types of known sprinklers (barn shutter, spraying, etc.) are capable of adapting to the nozzle 2 at its orifice 24 in order to apply the present together for all kinds of uses.

 the part of the nozzle 2 which has just been described already exists in the dosing pumps mentioned at the start. According to the present invention, it is characteristic that this part now consists of a single window with an envelope 27 also serving as a pusher. Indeed, the bottom of the tube 21 extends laterally around this tube and widens gradually to finally wrap the right cylinder of the container I. Outside the casing 27 of the push-piece 2, protrudes a grasping crown 26. Inside its flared section extend partitions 28. The latter can participate, with the outer surface of the tube 21, in guiding a return spring 4 disposed axially between the push-piece 2 and the body container. Finally, a cap 6 is advantageously provided for forcibly engaging the casing 27 of the push-piece 2 and protecting its orifice 24.

 The distribution assembly, the structure of which has just been detailed, is rather delivered to the manufacturer of product to be distributed, for example a pharmacist, devoid of its capsule 7. The manufacturer then pours product into the container-body of pump I then let it rest pump at the bottom. It is preferable that the quantity of product thus poured is limited to half the capacity of the container. Then, the manufacturer crimps the capsule 7 without changing the orientation of the distribution assembly. After these two operations only, the latter is ready to be delivered to the end user.

 The user in question is for example a patient wishing to administer one drop at a time of the product. Certain eye treatments indeed require such administrations with a dose just sufficient to spread over the surface of the eye and thus avoiding the elimination of an excess of product by the lacrimal duct. In this case, the user must remove the cap 6 and take the dispensing assembly between three fingers, the thumb and middle finger advantageously applying to the crown 26 of the push-piece 2 while the index finger presses. the bottom of the capsule 7. The assembly is also held with the orifice 24 downwards.

 From there, the actuation of the distribution assembly takes place in a similar manner to that of the distributors of the prior art provided with the preceding metering pumps. When, in fact, the user pushes the container-pump body 1 within the push-piece 2, the latter offering good guidance to the container, the return spring 4 compresses and the piston rod 3 rises inside the container. The piston 31 then tends to come out of the enclosure 1 I of the pump chamber while the free space between the base of the piston 31 and the bottom of the truncated cone 15 increases. The mouth of the conduit 35 emerges at the same time from the thin sealing lip 13. Assuming that the pump is primed, that is to say that the product already fills the channel 34, the latter then sees its pressure decrease as the pump chamber increases in volume.

 This is so until the container-body of the pump 1 abuts against the partitions 28 of the push-back pad 2. The distribution assembly is therefore found in the configuration of FIG. 2. It is noted that the length of the rod 32 is adjusted relative to the stroke of the container 1 1 in the nozzle 2 so that the piston 31-comes out completely from the enclosure 1 1 of the pump chamber. With the opening of the corresponding intake valve, the relative vacuum created in the pump chamber then causes a suction of the product. Provided that he bathes the enclosure 11, he enters the chamber and fills it. Note that, during the development of the phenomena reported so far, the valve 5 remains closed and isolates the entire product from outside.

 Then, when the user releases his effort and therefore authorizes the return spring 4 to relax, the piston 31 again engages in the enclosure 11. Thanks to the seal which is restored between the enclosure and the piston, closing so this intake valve, the pump chamber is therefore isolated. Immediately after, begins a decrease in its volume determined by the space in the enclosure 1 1 between the base of the piston 31 and the bottom of the truncated cone 15 of the container-body of the pompel. This results in an increase in the pressure of the product trapped in the chamber. By its flexibility, the lip 13 of the bottom of the truncated cone 15 of the container-pump body 1 also prevents any leakage of the product under pressure between the wall 12 and the rod 32. On the contrary, the pressure prevailing in the chamber applies this lip 13 to the rod 32 and this over a relatively large surface.

 However, in this transient phase, the mouth of the duct 35 is free so that the pressure of the product is communicated up to the valve 5. Given the design of the latter, it already opens for a pressure relatively little greater than atmospheric pressure. However, this is enough to guarantee a certain emission force to the product. The ribs 23 then complete its division before being expelled through the orifice 24 of the push-button erAbout 2. The beveled end of the orifice 24 also ensures detachment of the dropper.

 This is how the distribution assembly returns to its rest position according to FIG. 1. The volume of liquid expelled by the pumping device results in the creation or the accentuation of a depression in the container. In practice, this is not otherwise troublesome insofar as the air initially present in the container is in sufficient quantity (generally half of its capacity). The emptying of the container corresponds in this case to a final pressure of about half a bar which is entirely acceptable for the overall tightness of the container taking into account the presence of the sleeve 14. This is also insufficient to take off the enclosure 1 i of the piston 31 or else the lip 13 of the mouth of the conduit 35. Thus the channel 34 remains filled with liquid in order to ensure correct emission during the subsequent actuation of the pump. Furthermore, for greater safety, especially when the dispensing assembly has aged somewhat, the lip 13 is kept at rest curved against the base of the piston 31.

Its creep over time therefore tends more in the direction of an increasingly effective seal.

 The initiation of the embodiment which has just been detailed, however, imposes certain conditions for dimensioning the pump chamber. During the first actuation, while the channel 34 is still filled with air, a lower vacuum is established in the chamber. After opening its intake valve, it fills rather by gravity while the air is not significantly expelled from channel 34.

Priming is then possible only if the maximum capacity of the chamber is large enough compared to that of the canai. In practice, this imposes a lower limit on the size of the drops emitted around 5 microliters. Below this value, the initial air contained in the channel 34 could be compressed to offer space for the product coming from the pump chamber without creating an overpressure capable of opening the outlet valve 5.

 In the context of the present invention, it is however possible to overcome this limitation. The distribution assembly as shown in Figures 1 and 2 can indeed be filled, intake valve open. The manufacturer of liquid will have for this purpose the assembly in a receptacle now compressed the return spring 4.

While the piston 31 thus remains free from the enclosure 11, the product will be introduced into the channel 34 and will remain trapped there so soon the spring 4 again relaxed. However, provision should be made to fill the pump body container 1 with slightly pressurized product in order to correctly expel the air initially present in the channel 34 unless the size of the latter is sufficient to avoid the effects of capillary tension.

 Another embodiment of the present dispensing assembly is shown in axial section and in the rest position in FIG. 3. It differs from the previous one in the closure system of the container-pump body 1. This time, the product to be emitted is enclosed therein without air, a scraper piston 8 closing the open end of the container. A cover 7 is also snapped on over this end, the edge 18 of which has notches 19 for venting. Thus, a bearing surface is offered for actuating the dispensing assembly while the scraper piston 8 sinks into the container as it is emptied. Therefore, it is not imperative to keep the pump distribution assembly down to emit a drop of product.

 This second embodiment is advantageous when the product to be distributed must, for example, remain sheltered from air in order to avoid its chemical deterioration ... Compared with the first assembly mentioned here, it however results in greater loss of product. When the scraper piston 8 comes into contact with the piston 31, actuation of the dosing pump becomes impossible. Also the product remaining around the piston 31 can not be extracted from the container. In the absence of a scraper piston 8, the extraction of the product from the pump can continue on the contrary until the surface of the liquid drops below the edge of the enclosure 11. The truncated cone shape 15 of the pump body-container 1 also makes it possible to minimize the amount of product remaining in this dead volume. For the same purpose, it is also possible to give the scraper piston 8 a shape complementary to the piston 31.

 In one embodiment as in the other, tamper-evident tabs 1 8 can be molded onto the pump body container 1 as shown in FIG. 3. Although easily torn off by shearing, these tabs 18 have good compressive strength. Also, as long as a user has not deliberately removed them, they prevent any actuation of the dispensing assembly by providing a stop for the push-end piece 2. Likewise, they greatly facilitate the crimping operation of the capsule. or snap-on the cover made at the manufacturer of the product to be issued.

  Finally, it will be understood that the height of the container 1 and of its end piece 2 is a priori arbitrary. In particular, it is entirely conceivable that the container has the shape of a pipette. And many other variants will appear to those skilled in the art depending on the applications that interest him without departing from the object of the present invention mentioned in the following claims.

Claims (9)

Claims:  emission orifice (24).  elastic (4) in order to cause the emission of a drop of said product by said  two other fingers of said user who can thus compress said means  that said envelope (27) comprises gripping means (26) for applying  strong enough to receive pressure from a user's finger while  relative; and in that 3 / said open side (18) of said container (1) is closed by closing means (7)  (27) being moreover provided with stop means (28) for limiting said sliding  relative sliding of said container (1) and said envelope (27), said envelope  envelope (27) adapted to receive said container (1) with a clearance compatible with a  be filled with said product; in that 2 / said end piece (2) extends around said rod (32) of said piston (31) in one  pump in a container (1) open on the side (18) opposite said pump body for  (32) and said orifice (24) emitting said nozzle (2), characterized in that: Said pump body extends around said enclosure (11) of said chamber  to oppose the disengagement of said piston (31) from said enclosure (11), - as well as an outlet valve (5) disposed between said channel (34) emitting said rod  an emission orifice (24), elastic means (4) disposed between said pump body and said nozzle (2)  opens laterally to the mucin of said rod (32) under said piston (31), - a nozzle (2) adapted to be tightly secured to said rod (32) and having  being pierced with a central channel (34) communicating with a conduit (35) which  (II), a rod (32) passing through said pump body being integral with said piston (31) and  bottom, - a piston (31) adapted to engage and slide in leaktight manner in said enclosure  I.- Distribution assembly of a liquid or milk-like product per drop of small volume comprising: - a pump body which encloses a pump chamber having an enclosure (11) without  2. A dispensing assembly according to claim 1, characterized in that said container (1) consists of a plastic material of a flexibility comparable to that of low density polyethylene, said pump body then comprising a thin lip (13 ) sealing directed towards the inside of said chamber to apply to said rod (32) passing through said pump body, said rod (32) also having an annular cutout (36) into which opens said conduit (35) lateral.  3. A dispensing assembly according to claim 1 or claim 2, characterized in that said container (1) widens from said enclosure (it) in a truncated cone (15) so that there is an interior volume minimum between said container (1) and said enclosure (II).  4. A dispensing assembly according to any one of claims I to 3, characterized in that said closing means (7) of said container (1) consist of a capsule which is crimped after said container (1) is filled with produced for half of its capacity.  5. A dispensing assembly according to any one of claims I to 3, characterized in that said closing means (7) of said container (1) consist of a snap-on cover, an air vent (19) being provided between said open side (18) of said container (1) and said cover (7) and a scraper piston (8) being also sealingly engaged in said container (1) to separate said product from ambient air whatever the filling rate of said container (l)  6. A dispensing assembly according to any one of the preceding claims, characterized in that said container (1) protrudes from said envelope (27) when said elastic means (4) are at rest, said container (1) comprising tabs (18) tear-away tamper-evident offering a stop for said envelope (27) to prevent said relative sliding.  7. A dispensing assembly according to any one of the preceding claims, characterized in that said stop means (28) consist of several partitions integral with said envelope (27).  8. A dispensing assembly according to claim 7, characterized in that said elastic means (4) consist of a helical spring surrounding said rod (32), said spring being held externally by said partitions.  9. A distribution assembly according to any one of the preceding claims, characterized in that said orifice (24) of emission forms part of a nozzle integrated into said nozzle (2).