CH705799A1 - multi-dose dispensing head with shutter elastic membrane. Original: dispensing head multi-dose perfected. - Google Patents

Abstract

Multi-dose dispensing head, particularly for pharmaceutical products, comprising a dispensing nozzle (21) with shutter (10) housed in a metering chamber (23), in which the shutter housing means comprise a membrane (9) elastically deformable, arranged to seal said chamber (23), and connected to the shutter in such a way as to operate as an elastic suspension element of the shutter itself.

Description

Field of application

[0001] The present invention relates to a dispenser with controlled dosage, also known as dispenser-doser or "multi-dose", particularly for medical or cosmetic applications.

Known art

[0002] In the pharmaceutical or cosmetic sector, there is often the need for a dispenser with controlled dosage, that is, capable of delivering a predetermined and constant quantity of product, for each individual use. Dispensers of this type, also known as "multi-dose", are widely used, for example, for pharmaceutical products for topical use and for which a precise dosage is required, such as ophthalmic solutions.

[0003] A known multi-dose dispenser comprises a precharge volume, or precharge chamber, sized to contain exactly the quantity of product destined to the single dispensing (for example 50 microliters). The delivery is controlled by acting on a mobile unit of a delivery system such as a button contrasted by a spring.

[0004] A technical problem that occurs in multi-dose dispensers is to avoid contamination of the product by external agents, particularly outside air. Contact with external air is harmful not only due to the possible presence of pathogens, but also because contact with oxygen is often detrimental to the product.

[0005] An attempt to eliminate this problem consists in adding the product with a preservative and / or antibacterial; however, this expedient entails an additional cost, the need to intervene on the formulation of the product itself and, moreover, is not always acceptable. The preservative can in fact cause allergic reactions or other discomfort to the user: for example, some not inconsiderable contraindications of the preservatives used in ophthalmic products are known, which therefore advise against using this measure. Another solution consists of dispensers equipped with a spout with a protective filter, but it is also not satisfactory because the barrier effect of the filter is limited by the size of the pores, and in particular a filter is absolutely ineffective against viruses, and because a a small quantity of product that remains downstream of the filter, therefore in contact with the outside, can however contaminate the quantity dispensed.

[0006] There is therefore the need, in dispensers of the type considered here, to maintain the sterility of the product without resorting to preservatives, and therefore to effectively isolate the container from the outside world. In particular, it is necessary to prevent the actuation of the dispensing unit from causing an air inlet and / or an outflow of potentially contaminated product to the container. Other requirements of a multi-dose dispenser are reliability over time, consistency of the quantity supplied, and compatibility with different products both with reference to the state (liquids of various densities, sprays, etc.) and with reference to the composition. In addition, the economic aspect must not be lost sight of. They are in fact non-reusable devices and therefore there is an incentive to reduce the complication, the number of pieces and their cost as much as possible.

[0007] A multi-dose dispenser for liquid products without preservatives is known, for example, from EP 2 152 599. Said dispenser consists of a bottle equipped with a dropper spout and a flexible sheath for sealing the spout. However, it is suitable substantially only for liquid products to be dispensed in drops, ie substantially for aqueous solutions and is not very suitable, for example, for gel preparations; moreover it requires a relatively complex execution of the spout comprising sections with different taper and also comprising the aforesaid sheath.

[0008] The Italian utility model n. 266103, of the same applicants, describes a dispenser-doser comprising a rigid body, for example cylindrical, and a dispensing head screwed or otherwise fixed to the top of the cylindrical body. The cylindrical body contains a tank, the bottom of which is represented by a sealed piston, pushed by a spring against the bottom of the cylindrical body itself, to pressurize the product.

[0009] The dispensing head comprises a cylinder communicating with the tank. Said cylinder is also communicating with a chamber from which a dispensing nozzle departs. The nozzle is closed by a needle valve slidably housed in said chamber, normally closed due to a spring. A dispensing button is integral with the stem of a piston slidable in the cylinder and which, by moving, compresses the product contained in said cylinder and simultaneously closes the communication opening with the tank, substantially isolating said cylinder from said tank. Consequently, the advancement of the piston has the effect of considerably increasing the pressure in the cylinder and in the chamber communicating with it. When a sufficiently high pressure is reached, the force exerted by the product on the needle valve overcomes the thrust of the spring, thus opening the valve and allowing delivery. The quantity of product dispensed substantially depends on the stroke of the piston in the cylinder, and can be adjusted. At the end of the operation a new quantity of product is recalled in the cylinder by the container, without any contact with the external environment. In fact, the immediate re-closure of the needle valve, as soon as the pressure at the end of stroke of the piston decreases, prevents the entry of air into the chamber and the accumulation cylinder.

[0010] This dispenser-doser has a number of advantages, including the possibility of using liquid products of any density, as well as oily solutions, preserving the product from contact with the air. However, it still has room for improvement.

[0011] The needle valve needs a sliding seal on the walls of the chamber, adjacent to the nozzle, in which it is itself housed. The sliding seal can be made with a small o-ring or gasket, but requires a considerable dimensional accuracy of the components. The valve must be guided very precisely in the sliding seat, and the seat of the gasket must be made with minimum tolerances. Furthermore it is necessary to insert a small metal spring compressed between the head of the needle valve and a suitable stop surface.

[0012] All this involves a certain increase in costs. Furthermore, it has been found that the needle valve thus formed could lock up in the presence of a strongly saline solution and / or containing solid corpuscles, or that it tends to form crystals. In fact, the valve is in direct contact with the product and a solid particle, even microscopic in size, can hinder its flow. To try to overcome the problem of blocking or jamming of the needle valve, a second communication path can be provided between the cylinder and the tank, which however must be equipped with a non-return valve, increasing the number of components and the manufacturing cost.

Summary of the invention

[0013] The technical problem underlying the present invention is to overcome the limitations and drawbacks listed above. This object is achieved with a multi-dose dispensing head according to the appended claim 1, i.e. comprising: - a body with at least one product inlet opening; - at least one dispensing nozzle, - a chamber communicating with said opening and with said dispensing nozzle; - actuator means suitable for compressing the product inside said chamber; - a movable obturator housed in said chamber to close said nozzle, and openable due to the pressure in said chamber; characterized in that the shutter housing means comprise an elastically deformable membrane, arranged to seal a section of said chamber, in correspondence of a shutter housing area, and connected to the shutter in such a way as to react elastically to the opening movement of said shutter.

[0014] Said membrane in substance simultaneously acts as an elastic return element of the shutter and as a seal. In other words, said membrane can replace both a conventional return spring and the gasket (O-ring or equivalent) between the shutter and its guide. In some embodiments of the invention, the presence of a further shutter return means is not excluded; however in the preferred versions the membrane acts as the only elastic return element.

[0015] Preferably, the shutter is fixed directly to a portion of said membrane, for example to a central portion surrounded by a sealing region. More preferably, said membrane has a surface portion in communication with the product collection chamber, i.e. directly exposed to the pressure of the product during use. Thus, the pressure induced by the actuator means acts directly on the membrane, deforming it and causing the shutter to open.

[0016] In an even more preferred embodiment, said membrane comprises a shutter supporting region, for example in the central part of the membrane itself, and a sealing region around said supporting region. The sealing region is clamped against an abutment surface of the body, for example by means of a ring nut or equivalent means; the tightening of said membrane region has at the same time the effect of fixing the membrane itself, and consequently also of the movable shutter associated therewith, and of providing a sealing area.

[0017] In a preferred embodiment, the membrane comprises at least one wave or bellows portion, which connects said shutter supporting region to said fastening and sealing region. Said wave essentially acts as a suspension of the movable shutter, between a substantially fixed portion of membrane, for example because it is clamped by the described ring nut, and a portion of a movable membrane together with the shutter itself.

[0018] In the preferred embodiment the membrane has substantially the shape of a disk and the sealing and fixing region is substantially an annular edge or peripheral crown of said disk.

[0019] Advantageously, the membrane is made of plastic or rubber or elastomer, resistant to wear caused by the use of oxidizing or saline substances.

[0020] The shutter is represented for example by a needle valve, with or without a gasket at the nozzle, depending on the need. In a preferred embodiment the pin is guided by a fixed tube, mounted inside said chamber; the head of the pin comprises a blind threaded hole, and the pin is fixed to said membrane by means of a screw passing through a central hole of the membrane itself and engaged in said blind hole.

[0021] The nozzle can have a substantially constant passage section, or a diverging section towards the outlet. Furthermore, the nozzle can be aligned in the axial direction of sliding of the needle valve, or inclined at a suitable angle.

[0022] The actuator means advantageously comprise a sliding piston whose advancement compresses the product in the chamber, and at the same time obstructs the product inlet opening, thus obtaining the compression and subsequent delivery of a controlled volume of product.

[0023] The dispensing head according to the invention is connected to a container of the product, thus forming a multi-dose dispenser. Said container, according to various embodiments, can be rigid or even flexible. In some further embodiments, a dispenser can comprise a double system comprising two tanks for the components of a two-component product; two dispensing heads controlled simultaneously by a single activation key; a common outlet nozzle in which the individual components of the product are mixed.

[0024] An advantage of the invention consists in the considerable constructive simplification. Thanks to the membrane, which acts both as an elastic return element and as a sealing element, precise assembly or sealing between the shutter and its guide is not required, and a sliding seal associated with the shutter is not necessary. The fact of adopting less precise processes, without compromising reliability, allows a considerable reduction in costs. Another advantage is that the needle valve is substantially freed from locking problems. Being able to adopt less strict tolerances, the group becomes less vulnerable to jamming caused by micro-corpuscles or crystals, for example in the presence of a strongly saline product with phenomena of local precipitation and formation of solid micro-granules. Being practically eliminated the risk of jamming (seizing) of the shutter, the construction can be simplified avoiding an additional connection channel between the head and the tank and the relative non-return valve.

[0025] The invention is applicable to a wide range of pharmaceutical products, cosmetics, etc. regardless of their composition and their physical state (density, viscosity, etc.). The invention is applicable, among other things, to products that are presented as aqueous solutions, gels, or in spray. A preferred example of application is represented by multi-dose dispensers of gel ophthalmic products.

[0026] Another advantage of the invention is the fact that the product container can also be flexible, for example in PE, and not necessarily rigid. This is due to the fact that the pressurization of the product is entirely caused by the actuator means, advantageously represented by a piston, of which the head is equipped.

[0027] The actuation is soft and progressive due to the elastic reaction of the membrane to the pressure exerted on it by the product.

[0028] Further advantages of the present invention will become clear from the description given by way of example, with reference to the attached figures.

Brief description of the drawings

[0029] <tb> Fig. 1 is a sectional view of a dispensing head according to a first preferred way of carrying out the present invention. <tb> Fig. 2 <sep> is an enlarged view of a detail of fig. 1. <tb> Fig. 3 is a sectional view of a dispensing head according to another preferred way of carrying out the present invention. <tb> Fig. 4 is a plan view of the inner membrane of the dispensing head of Fig. 1 or of fig. 3. <tb> Fig. 5 <sep> is a section of the membrane of fig. 4. <tb> Fig. 6 shows an example of a dispenser comprising a dispensing head according to the invention. <tb> Fig. 7 <sep> shows an example of a dispenser for a bi-component product according to another application of the invention.

Detailed description of a preferred embodiment

[0030] With reference to fig. 1 is shown in section a dispensing head according to a preferred way of carrying out the invention.

[0031] The head comprises a body generally indicated as 30, preferably of plastic material, which in the example is essentially formed by the union of a half-body 1 and a half-body 2.

[0032] The dispensing head has a product inlet opening 22, which communicates with a chamber 23 through a conduit 20. The dispensing head of Fig. 1, in use, is mounted on a product container, not shown, communicating said opening 22. The container can be rigid or flexible.

[0033] Said chamber 23 communicates with a dispensing nozzle 21, which is closed by a movable shutter, here represented by a needle valve 10 housed in the chamber 23.

[0034] The nozzle 21 in the figure is a divergent duct suitable for dispensing sprays but in other executions, completely equivalent, the dispensing nozzle can have a constant section. The orientation of the nozzle can also vary according to the contingent needs, related to the type of product, the methods of use, etc. for example being axially aligned with the needle valve 10, or inclined.

[0035] The needle valve 10 can be provided with a gasket 13 (fig. 2) for sealing against a seat for entering the nozzle 21; this gasket is optional and can be omitted in other executions of the invention. In some embodiments, the shutter may comprise a zone covered with a deformable material, such as a silicone material, with a gasket effect. For example, the needle valve 10 may comprise a silicone-coated tip in place of said gasket 13.

[0036] The needle valve 10 is designed to open (moving from right to left, in the figure) due to an increase in pressure in the chamber 23.

[0037] In greater detail, the increase in pressure is caused by an actuation button 3 which acts on a piston 4 which is housed in the half-body 1 and is slidable in a cylindrical portion 20a of said duct 20 for communication between the opening 22 and said chamber 23.

[0038] The piston 4 is opposed by a coaxial spring 6 and is provided with at least one seal 5 against the wall of the conduit part 20a. The gasket 5 is on the opposite side of the branch 20 for connection with the chamber 23, with respect to the product inlet opening 22. In the example the gasket 5 is double and is represented by two O-rings.

[0039] Depending on the machining precision, the o-ring gaskets present on the actuator piston 4 may be omitted or replaced by creating an elastic seal ring ("herringbone" type) on the piston itself.

[0040] A screw 7 acts as an element for adjusting the limit switch of the key 3 and of the piston 4.

[0041] Referring now more in detail to the needle valve 10, said valve 10 is slidable in a guide tube 8 which is fixed in a suitable seat of the half-body 2, inside the chamber 23.

[0042] The needle valve 10 is fixed to an elastically deformable membrane 9, by means of a screw 12. Said membrane 9 substantially operates both as an elastic suspension and return element, keeping the valve closed against the filling seat of the nozzle 21 , both as a sealing element for sealing the chamber 23 from the outside world, due to a clamping ring 11 which compresses the edge of the membrane itself. The ring nut 11 in more detail is mounted, for example screwed, in a seat 15 of the half-body 2, closing the chamber 23 from the opposite side of the dispensing nozzle 21.

[0043] In the form shown, the membrane 9 is substantially a disk with a peripheral portion 9a and a central portion 9b connected by a ripple 9c which acts as a suspension. The part 9a, as can be seen, is compressed by the ring 11 against a surface 16 of the half-body 2, thus sealing the chamber 23 with respect to the seat 15 for mounting the ring nut (Fig. 2).

[0044] The pin 10, slidable in the guide 8, is fixed to the central portion of membrane 9b, by means of said screw 12 which engages a blind threaded hole 14 formed in the head of the pin 10. It should be noted that said screw 12 is through in a central hole 9e of the membrane 9; however, another hermetic seal is created due to the compression of the membrane zone 9b, between the head of the pin 10, on one side, and the head of the screw 12, on the opposite side. In this way, the chamber 23 remains perfectly sealed.

[0045] The needle valve 10 slides with sufficient precision inside the guide tube 8, however the coupling is not sealed and has a play, visible in fig. 2, so that the region 24 between the head of the guide 8 and the membrane 9, is in communication with the chamber 23. Consequently the membrane surface indicated as 9d is substantially exposed to the pressure of the product contained in the chamber 23 or in the region 24 with it communicating.

[0046] Basically it will be noted from the figure that the movable element represented by pin 10 and screw 12 can be moved, elastically contrasted by the membrane 9, with respect to the fixed guide 8, with a hermetic seal ensured by the same membrane 9 sealed between the ring nut 11 and supporting surface 16, as well as tightened by the screw 12 in correspondence with the anchorage of the pin 10.

[0047] Fig. 3 shows another preferred embodiment in which the details are indicated with the same references as in Figs. 1-2. In this embodiment it can be seen that the duct 20 has a different course with an "elbow" curve and that the nozzle 21 has a constant rather than a diverging section. In Fig. 3 the nozzle 21 is coaxial to the pin 10 but in other embodiments the nozzle 21 can be "tangential", that is inclined with respect to the axis of the pin. The choice of the type of nozzle and / or its inclination depends on the product and use.

[0048] Figs. 4 and 5 show in more detail the membrane 9 and the respective sealing parts 9a and 9b for anchoring the pin 10, connected by the suspension 9c. The hole 9e is also noted for the screw 12 shown in figs. 1-2.

[0049] Fig. 6 shows a dispensing head, for example in the embodiment of fig. 3, forming part of a multi-dose dispenser 100 comprising a product tank 101 with an opening 102 communicating with the described inlet opening 22 produced in the head.

[0050] Fig. 7 shows an example of application to a dispenser of a two-component product. The dispenser 200 comprises two tanks 201 and 202 for two components of a product, each with an opening 203, 204 which communicates with a dispensing unit according to the invention and, for example, of the type of fig. 1-2 or fig. 3. Each of the groups 31, 32 comprises a respective shutter 10 and membrane 9; preferably the groups 31, 32 are operated simultaneously by pressing a single key 3 and the respective nozzles deliver a predetermined quantity of the component. The components mix at the outlet in the common nozzle 33.

[0051] Returning now to figs 1 and 3, the operation is as follows. In rest conditions, a certain quantity of product is present in the channel 20 and in the chamber 23, in communication through the opening 22 with the produced container.

[0052] By pressing the button 3, the piston 4 slides in the guide section 20a and intercepts and substantially closes the opening 22, thus isolating the channel 20 and the chamber 23. Advancing to the end of its travel, as shown in Fig. 1, the piston 4 acts as a pump-piston, compressing the product. The pressure in the chamber 23 propagates in the zone 24 in contact with the membrane 9 and acts on the face 9d of the membrane. When the pressure exceeds a threshold value, the membrane deforms with displacement (towards the right in the figure) of the portion 9b, which is substantially suspended from the edge 9a by means of the suspension part 9c. With the diaphragm, the pin 10 fixed to it is moved, thus opening the dispensing way produced through the nozzle 21.

[0053] As is apparent to a person skilled in the art, the size of the duct 20, the chamber 23 and the piston 4 determine the quantity dispensed. The output of the product causes a drop in pressure and, consequently, the closure of the pin 10 due to the elasticity of the membrane, which returns to its original shape.

[0054] The division of the body into parts 1 and 2 allows an easy assembly of the guide 8, the pin 10 and the membrane 9. Substantially the components can be easily inserted from the side of the opening 15, and the whole is then closed and sealed from the ring 11. Preferably the guide 8 is glued to the body 2, in correspondence with the abutment surface 17 of fig. 2; the gluing is applicable as the components are usually made of plastic. Then the pin 10 is inserted into the guide 8, then the membrane 9 to which the pin is screwed by means of the screw 12 (which can be for example a screw M1); finally, the ring nut 11 is screwed down until the sealing edge 9a of the membrane is compressed.

[0055] The invention, as it is understood, not only reduces the number of components but also facilitates assembly with respect to an execution with very precise tolerances, metal springs, etc.

[0056] A two-component dispenser of the type shown in fig. 7 is used for products that must be mixed together only at the time of use, for example a carbonate salt with an acid, which cannot coexist in the same tank (development of carbon dioxide). This dispenser structure is also suitable for administering certain drugs which are soluble or stable in an acid environment, for example fluorchinolonics, but the acidity of the environment in which they are stable is incompatible with the human body, for example with the eyes, in which it is necessary to inject a slightly basic solution. Other examples are hydrophilic substances or solutions with lipophilic substances; these substances require the use of a stabilizing surfactant which is nevertheless harmful to the ocular surface or mucous membranes.

Claims (14)

1. Multi-dose dispensing head comprising: - a body with at least one product inlet opening (22); - at least one dispensing nozzle (21); - a chamber (23) communicating with said opening (22) and with said dispensing nozzle; - actuator means (4) suitable for compressing a predetermined quantity of product inside said chamber; - a movable shutter (10) housed in said chamber to close said nozzle, said shutter being openable due to the pressure in said chamber; characterized in that the obturator housing means comprise an elastically deformable membrane (9) arranged to seal a section of said chamber (23), in correspondence of a housing area of the shutter (10), and connected to the shutter in such a way as to react elastically to the opening movement of said shutter. 2. The dispensing head according to claim 1, wherein the shutter is fixed directly to a portion of said membrane. 3. Dispensing head according to claim 1 or 2, said membrane comprising a region (9d) in communication with said chamber (23), and thus directly exposed to the product under pressure in said chamber, and at least one sealing region (9a) that surrounds this region in contact with the product. 4. Dispensing head according to claim 3, said membrane comprising a supporting region (9b) of the shutter, and said sealing region being arranged around said membrane supporting region of the shutter. 5. Dispensing head according to claim 3 or 4, said sealing region being clamped against a stop surface (16) of the body, with the effect of fixing the membrane itself and sealingly closing said chamber (23). 6. Dispensing head according to claim 4 or 5, wherein said membrane comprises at least one wave or bellows portion (9c) which connects said membrane supporting region of the shutter (9b) and said fastening and sealing region ( 9a). 7. The dispensing head according to any one of the preceding claims, the membrane (9) being substantially formed as a disk. 8. The dispensing head according to claim 7, comprising a ring nut (11) for clamping the membrane to the body, said ring nut being inserted in a body mounting seat and sealingly compressing a peripheral annular region of said membrane against a surface of the body which substantially surrounds the shutter housing area. 9. Dispensing head according to any one of the preceding claims, said obturator (10) being represented by a needle valve and said housing means comprising a guide tube (8) mounted inside said chamber (23). 10. The dispensing head according to claim 9, wherein the needle head comprises a blind threaded hole (14), and the pin is fixed to said membrane by means of a screw (12) passing through a central hole of the membrane itself and engaged in said blind hole, a portion (9b) of membrane being tightly sealed between said screw and an edge of said threaded hole. 11. Dispensing head according to any one of the preceding claims, said membrane being made of an elastomeric material. 12. Dispensing head according to any one of the preceding claims, said nozzle (21) having a substantially constant or divergent section towards the outlet. 13. Dispensing head according to any one of the preceding claims, in which the said actuator means comprise a push-button (3) associated with return elastic means (6) and a piston (4) slidingly sealed in a channel (20a) communicating with said chamber (23), said piston also being arranged to seal the product inlet opening (22). 14. Multi-dose dispenser (100, 200) comprising a dispensing head according to any one of the previous claims.