EP4688280A1

EP4688280A1 - Dispenser for dispensing a fluid

Info

Publication number: EP4688280A1
Application number: EP24719891.4A
Authority: EP
Inventors: Lamberto Carta; Fabrizio Camplone
Original assignee: Aptar Italia SpA
Current assignee: Aptar Italia SpA
Priority date: 2023-04-03
Filing date: 2024-03-27
Publication date: 2026-02-11
Also published as: CO2025014307A2; CN120916849A; IT202300006456A1; WO2024209309A1; AR132235A1; MX2025011802A

Abstract

Described is a dispenser (1) for dispensing a fluid comprising a containing body (2) which can be inserted in a bottle, a ring nut (9) which can be screwed on the neck of the bottle and a dispensing head (13). The dispenser (1) also comprises a piston (6) slidable inside the containing body (2) and a hollow stem (3) associated below the piston (6). Inside the containing body (2) there is a concertina-like deformable element (7), defining a return spring, the concertina-like deformable element (7) being made of plastic material.

Description

DESCRIPTION

DISPENSER FOR DISPENSING A FLUID

This invention relates to a dispenser for dispensing a fluid, that is to say, a dispensing device applicable to the neck of a bottle in order to dispense the fluid contained in the bottle.

As is known, a dispenser is commonly used for dispensing liquid, such as, for example soap (or other product not explicitly mentioned below).

The liquid is contained in a bottle with which the dispenser is associated by means of suitable connecting means.

These dispensers for dispensing fluid are located in the market for single-use products, where the attention for these products is increasingly oriented towards sustainable solutions with a low environmental impact.

In particular, a requirement for products in the so-called packaging sector, to which liquid dispensers form part, is to limit the variety of raw materials used, possibly with a view to solutions consisting of a single type of material or, alternatively, materials belonging to the same family.

Currently, the dispensers on the market commonly comprise metallic springs inserted in devices made mainly of materials belonging to the family of polymers. The devices on the market which involve the replacement of the metal spring use as an alternative elastic plastic components characterised by considerable dimensions and weight, that is to say, solutions which deviate both aesthetically and structurally and functionally from the typical design of dispensers with metal springs.

Disadvantageously, the plastic springs currently on the market tend to lose their elastic force and reduce their return capacity if kept in constant compression (stress relaxation).

The technical purpose of the invention is therefore to provide a dispenser for dispensing a fluid which is able to overcome the drawbacks of the prior art. The aim of the invention is therefore to provide a dispenser for dispensing a fluid made entirely with materials which are easy to dispose of and then recyclable with the entire packaging.

A further aim of the solution is to provide a dispenser for dispensing a fluid which is easily recyclable and has small dimensions and weight and maintains technical features similar to the traditional solutions, with springs made of metal, already present on the market.

A further aim of the invention is to provide a dispenser for dispensing a fluid which is able to preserve the return capacity of the spring.

A further aim of the invention is to provide a dispenser for dispensing a fluid with greater reliability and better sealing characteristics without adversely affecting the production costs and allowing the recovery of existing equipment already made for the dispensers with metal springs.

Lastly, a further aim of the invention is to provide a dispenser for dispensing a fluid which retains all the functional and performance features of traditional dispensers with a metal spring, both in relation to the protection and the safeguarding of the integrity of the package and the relative contents, and with regard to the effectiveness and comfort of use.

The technical purpose indicated and the aims specified are substantially achieved by a dispenser for dispensing a fluid comprising the technical features described in one or more of the appended claims. The dependent claims can correspond to possible embodiments of the invention.

The invention describes a dispenser for dispensing a fluid comprising a hollow containing body, which can be inserted in a bottle, made of plastic material, and comprising an orifice for sucking fluid from the bottle.

According to an aspect of the invention, the dispenser comprises a ring nut which can be screwed on the neck of the bottle.

Preferably, the ring nut comprises a shoulder, covering and associated with a flange of the containing body, and may also comprise a collar extending below the shoulder, according to the axis of the ring nut.

The dispenser comprises a piston slidable inside the containing body between a raised position and a lowered position.

The dispenser also comprises a hollow stem axially slidable inside the containing body and associated below the piston.

According to an aspect of the invention, the dispenser comprises a retaining ring integral with the containing body and inserted in it.

The retaining ring houses and guides the hollow stem in its movement inside the containing body.

Preferably, the retaining ring also defines between the containing body and the hollow stem a containment space.

Preferably, the retaining ring is configured for guiding the hollow stem defining two possible so-called “rest” positions: a first raised operating position and a second non-operating or stop position raised further relative to the first position.

According to an aspect of the invention, the dispenser comprises a concertina-like deformable element, defining a return spring of the dispenser.

The concertina-like deformable element comprises a lateral wall extending between an upper portion and a lower portion of the concertina-like deformable element.

Preferably, the lateral wall is inserted in the containment space coaxially with the hollow stem.

Preferably, the upper portion of the lateral wall is in contact with a radial protrusion of the hollow stem, whilst its lower portion is in contact with a lower portion of the retaining ring.

The concertina-like deformable element is made of plastic material.

Advantageously, having a spring made of plastic (that is to say, the concertinalike deformable element), the dispenser for dispensing a fluid is easily disposed of and then recyclable with the entire packaging.

Advantageously, the plastic spring, having small dimensions and limited weight, allows the overall aesthetic and dimensional characteristics of the dispensers to be maintained which are similar to the traditional solutions, with a metal spring, already present on the market. Advantageously, the particular shape of the concertina-like deformable element and the morphology of the ring also allow the same functional features of a metal spring to be maintained inside the dispenser.

According to another aspect of the invention, the dispenser comprises a dispensing head.

The dispensing head comprises a central portion connected to an upper portion of the hollow stem for controlling the actuation of the piston.

The dispensing head also comprises a spout designed to dispense the fluid contained in the bottle.

The dispensing head can be pressed by a user between a raised position, wherein the lateral wall of the concertina-like deformable element is axially extended, and a lowered position, wherein the lateral wall of the concertina-like deformable element is axially compressed.

Further features and advantages of the invention are more apparent in the nonlimiting description which follows of a preferred non-exclusive embodiment of a dispenser for dispensing a fluid.

The description is set out below with reference to the accompanying drawings which are provided solely for purposes of illustration without restricting the scope of the invention and in which:

- Figures 1A, IB, 1C and ID are schematic representations of a first embodiment of a dispenser according to the invention;

- Figures 2 A, 2B, 2C and 2D are schematic representations of a second embodiment of a dispenser according to the invention.

With reference to the accompanying drawings, the numeral 1 denotes in its entirety a dispenser for dispensing a fluid which, for simplicity of description, will be referred to hereafter as the dispenser 1.

The dispenser 1 comprises a containing body 2 and a ring nut 9.

The ring nut 9, associated with the containing body 2, is configured to be screwed or can be screwed to the neck of the bottle or coupled by means of an undercut system. The containing body 2 is hollow and can be inserted in a bottle. The containing body 2 is preferably axisymmetric in shape and comprises a top portion 2a and a bottom portion 2b.

The top portion 2a of the containing body 2 is open and allows the components which make up the dispenser 1 to be inserted into the hollow body 2.

In the bottom portion 2b, the hollow body 2 comprises an orifice for sucking fluid from the bottle. In other words, the liquid contained in the bottle enters the containing body 2 through the orifice.

In the bottom portion 2b a valve 4 may be suitably located, configured to open and close the orifice in a manner which will be described in more detail below.

According to a possible embodiment, the valve 4 is substantially “cup-shaped” and comprises an upper cylindrical extension which guides the motion, preventing the seizing and a spherical sealing surface, located on a corresponding conical surface of the containing body 2.

According to a possible embodiment, shown in Figures 2A-2B, the valve 4 has a spherical shape and is made of plastic material.

The containing body 2 also has a central portion 2c defining a dosing chamber 10 and a suction pipe which draws up the product to be dispensed close to the bottom of the bottle.

The valve 4 rises when the flow of fluid passes through the suction pipe and enters the dosing chamber 10, allowing in this way the entrance of the liquid. During the dispensing, due to the pressure in the fluid, the valve 4 lowers and returns to position, sealing the bottom portion 2b.

In other words, the ball of plastic material starts hypothetically from a suspension state, wherein the valve is open, and only subsequently, during dispensing, the valve closes due to the overpressure.

Preferably, but not necessarily, the containing body 2 has a geometry which is substantially funnel-shaped.

The three portions 2a, 2b and 2c mentioned above preferably differ in terms of their transversal dimensions, so as to define the above-mentioned funnel-shaped configuration of the containing body 2. The dispenser 1 also comprises a hollow stem 3 slidable axially inside the containing body 2 between a raised position and a lowered position.

The hollow stem 3 axially slidable inside the containing body 2 has at the top a radial protrusion 5b and at the bottom one or more lateral windows 5a.

The hollow stem 3 is designed to transfer, through its cavity, the liquid present to the inside of the dosing chamber 10. In particular, the hollow stem 3 comprises at least one window 5a (preferably it comprises two, even more preferably opposite to each other). The window 5a is configured to place in fluid communication the cavity of the hollow stem 3 with the inside of the containing body 2, and in particular with the dosing chamber 10 of the central portion 2c. Preferably, but not necessarily, the window 5a (or the windows 5a) is made on the lateral wall of hollow stem 3.

Preferably, but not necessarily, the end portion of the hollow stem 3 is closed, so that the liquid in the dosing chamber 10 can enter the cavity of the stem only through the window 5a.

According to a possible embodiment, the hollow stem 3 comprises a tip 5 hooked below the hollow stem 3 by means of a system of undercuts.

Preferably, according to this embodiment, at least one window 5a which allows the passage of the product to be dispensed from the dosing chamber 10 of the central portion 2c of the containing body 2 is made on the tip 5 of the hollow stem 3.

Preferably, the hollow stem 3 is made of two or more modules according to the requirements of the assembly lines. More preferably, the modules of the hollow stem 3 have a versatile assembly orientation.

In other words, the hollow stem 3 may be made in two pieces or modules according to a stem combined with lower tip configuration. The tip 5 is in turn equipped with a system of undercuts which attach to corresponding undercuts of the stem. The system of undercuts is sized to allow an assembly with loads which are not too high and which are compatible with the structural resistance of the components but which, at the same time, guarantee a high level of axial retention. Advantageously, these embodiments of the hollow stem 3 result in greater reliability and better sealing characteristics without adversely affecting production costs and allowing the recovery of existing equipment already made for dispensers with metal springs. In effect, by adopting technical solutions which allow quick and easy assembly processes advantages are obtained regarding hourly productivity and the energy needed to produce the dispenser 1.

According to a further embodiment, the stem module may have an undercut to which it is possible to rigidly connect a tubular extension 15.

The tubular extension 15 is integrally connected to the hollow stem 3 by means of snap-on profiles 15b made on said tubular extension 15.

The tubular extension 15, as well as having the purpose of preparing a stop system, allows the axial assembly of finishing components, such as, for example, dispensers without the need for the complete operation of the dispenser 1.

Advantageously, the tubular extension 15 allows a faster assembly process if protective elements are used, such as, for example, clips.

The dispenser 1 also comprises a piston 6 slidable inside the containing body 2 between a raised position wherein the volume of the dosing chamber 10 is at its maximum, and a lowered position wherein the volume of the dosing chamber 10 is at its minimum.

The piston 6 comprises an outer surface designed to come into contact with the inner wall of the dosing chamber 10 of the containing body 2 and an inner surface associated with the hollow stem 3, connected by a closed surface with a radial extension.

According to a possible embodiment of the piston 6, the closed surface with a radial extension has a reverse configuration designed to reduce as much as possible the minimum volume which the dosing chamber 10 adopts with the piston 6 in the lowered position.

The hollow stem 3 is associated with the piston 6 and is configured for controlling the activation. In other words, the piston 6 is associated below to the hollow stem 3 which is configured to move the piston 6 inside the dosing chamber 10 defined in the central portion 2c of the containing body 2. The hollow stem 3 is, therefore, associated at the bottom, in a slidable fashion, with the piston 6 for controlling the opening of the lateral windows 5a and selectively allowing the passage of the fluid contained in the dosing chamber 10 of the containing body 2.

According to a possible embodiment, the tip 5 of the hollow stem 3 has a conical sealing surface and a wide lower extension designed to favour the engagement with the piston 6.

The piston 6, controlled by the hollow stem 3, slides between the above- mentioned raised position, in which the volume of the dosing chamber 10 is at its largest, and the above-mentioned lowered position, where the volume of the dosing chamber 10 is at its smallest.

The piston 6 slides with a fluid-tight seal along the inner wall of the containing body 2.

The hollow stem 3 is at least partly slidable relative to the piston 6 in such a way that the window 5a is occluded or released by mutual sliding between hollow stem 3 and the piston 6.

When the lowering of the mobile unit comprising the hollow stem 3 and piston 6 creates an overpressure inside the dosing chamber 10, the piston 6 rises, the cavity of the hollow stem 3 is in fluid communication with the dosing chamber 10 through the lateral windows 5a and the fluid in the dosing chamber 10 rises along the hollow stem 3.

According to this configuration, the 4 valve is lowered and occludes the above- mentioned orifice due to the overpressure in the dosing chamber 10.

When the raising of the mobile unit comprising the hollow stem 3 and piston 6 creates a negative pressure inside the dosing chamber 10, the piston 6 lowers, the cavity of the hollow stem 3 is not in fluid communication with the dosing chamber 10 and fluid is sucked into the dosing chamber 10 of the containing body 2 from the bottle.

In this configuration, the valve 4 rises, leaving the above-mentioned orifice open, due to the negative pressure in the dosing chamber 10. According to the dispenser 1 described in this invention, the sliding of the movable unit consisting of hollow stem 3 and piston 6 inside the containing body 2 occurs by opposing the action of a concertina-like deformable element 7, defining a return spring of the dispenser 1, housed inside a containment space formed between the hollow stem 3 and the containing body 2.

The concertina-like deformable element 7 made of plastic is positioned outside the dosing chamber 10 to minimise the risks of chemical compatibility problems.

The concertina-like deformable element 7 is made of plastic material and comprises a lateral wall 8 extending between an upper portion and a lower portion of the concertina-like deformable element 7 and is designed to put the hollow stem 3 in a raised position together with the piston 6.

Preferably, the upper portion of the concertina-like deformable element 7 is in contact with the radial protrusion 5b present in the upper part of the hollow stem 3.

Preferably, the concertina-like deformable element 7 is made in the form of a spring with a V-shaped profile with a helical and conical extension.

Advantageously, this morphology guarantees a geometry which provides the necessary loads in the spaces allowed by a conventional dispenser 1.

The lateral wall 8 is inserted in the containment space, coaxially with the hollow stem 3 and having the upper portion in contact with the radial protrusion 5b of the hollow stem 3.

The upper portion of the lateral wall 8 of the concertina-like deformable element 7 may also comprise compensation passages aligned with or which can be aligned with corresponding passages for compensating the radial protrusion 5b of the hollow stem 3 configured for the entry or exit of air from said concertina-like deformable element 7.

According to a possible embodiment, the concertina-like deformable element 7 comprises anti-unscrewing ribs in the lower portion.

Advantageously, the anti-unscrewing ribs allow various modes of moulding the concertina- like deformable element 7, for example blowing or unscrewing. The dispenser 1 also comprises a retaining ring 14 integral with the containing body 2 and inserted inside it. In particular, the lower portion of the retaining ring 14 is in contact with the lower portion 8 of the concertina- like deformable element 7.

The containing body 2 is therefore closed at the top by the retaining ring 14, which is hooked inside the body through a system of undercuts and anti-rotational ribs.

The retaining ring 14 is configured for guiding the hollow stem 3 in its movement inside the containing body 2.

The retaining ring 14 defines an upper limit of the dosing chamber 10. This upper limit prevents the piston 6 from coming out from the dosing chamber 10 of the containing body 2.

In other words, the retaining ring 14 guides the hollow stem 3 and the piston 6 in their movement inside the containing body 2, also delimiting an upper containment space inside the latter.

According to a possible embodiment, the retaining ring 14 is configured to define an operating configuration and a non-operating configuration of the dispenser 1. The term “operating configuration” means a configuration wherein the dispenser 1 can be actuated and is able to dispense the fluid drawn from the bottle.

The term “non-operating configuration” means a configuration wherein the dispenser 1 cannot be actuated and is therefore not able to dispense the fluid.

In other words, the retaining ring 14 is configured for guiding the hollow stem 3 along the actuation stroke, and preferably defines two so-called “rest” positions of the dispenser 1: a first raised operating position wherein the piston 6, at the end of the raising stroke determined by the return of the elastic concertina-like element 7, is in contact with the lower portion of the retaining ring 14, and a second nonoperating, or stop, position obtained preferably by the reciprocal rotation between the tubular extension 15 and the retaining ring 14 which determines the locking of the slidable parts, wherein the hollow stem 3 is locked in a position further raised relative to the first raised operating position.

In other words, the first raised operating position is at a height slightly lower than the second stop position, in order to recover the relaxing effects of the concertinalike deformable element 7.

Preferably, but not necessarily, the piston 6 is housed in a tubular cavity of the retaining ring 14 provided with an undercut in such a way that the piston 6, in contact with said undercut, limits the raising stroke of the hollow stem 3 and defines a first raised operating position lower than the second non-operating or stop position.

In other words, the first operating position is obtained by means of undercuts suitably positioned on the lower portion of the retaining ring 14 against which rest corresponding abutments made on the piston 6, to stop the raising stroke of the piston.

Preferably, but not necessarily, the reciprocal rotation between the tubular extension 15 and the retaining ring 14, which determines the locking of the slidable parts, allows the further lifting of the piston 6 and the hollow stem 3, thanks to a ramp 14a made preferably using a protruding profile made on the inner surface of the retaining ring 14, to which suitable protrusions 15a made on the outer surface of the tubular extension 15 are constrained, slidably movable on the ramp 14a.

In other words, the second non-operating position is reached by means of a rotation manoeuvre which determines the lifting of the hollow stem 3.

Preferably, the reciprocal rotation is facilitated by the supporting constraint of the protrusions 15a formed on the tubular extension 15 connected rigidly with the hollow stem 3, slidably movable on the ramp 14a made on the retaining ring 14. Preferably, the protrusions 15a made on the tubular extension 15 rest on the ramp 14a, made on the retaining ring.

Alternative configurations, such as that illustrated in Figures 2A, 2B, 2C and 2D may comprise a similar lifting mechanism, again made by means of a supporting constraint between slidable elements suitably made on one of the components integral with the hollow stem 3 described below, and a suitable ramp 14a with a guide function, again made on the retaining ring 14, and with appropriate morphology. Advantageously, in the non-operating position, the concertina-like deformable elastic element 7 is less compressed than in the first raised operating position. This limits the effects of the relaxation due to the prolonging over time of the compression condition to which the concertina-like deformable elastic element 7 is subjected with the dispenser 1 stopped.

Designed to guarantee the coupling between the outer surface of the retaining ring 14 and the inner surface of the containing body 2, the ring nut 9, according to a possible embodiment, may comprise a shoulder 11, covering and associated with a flange 2d of the containing body 2.

Preferably, the ring nut 9 couples to the containing body 2 and to the retaining ring 14, by means of a collar 11b, associated with the shoulder 11, extending preferably inside the retaining ring 14, in such a way that, once screwed on the bottle, it prevents the removal of the retaining ring 14 and guarantees a high level of retention.

Preferably, but not necessarily, the ring nut 9 has on the shoulder 11 a lip I la associated with the tubular extension 15 for making a fluid-tight seal which prevents or limits the entry of water if the dispenser 1 is exposed to a jet of external water during use.

The dispenser 1 also comprises a dispensing head 13 having a central portion connected integrally to an upper portion of the hollow stem 3 for controlling the actuation of the piston 6 and a spout designed to dispense the fluid contained in the bottle.

The dispensing head 13 can be pressed by a user between a raised position wherein the lateral wall 8 of the concertina-like deformable element 7 is axially extended, and a lowered position, wherein the lateral wall 8 is axially compressed. In other words, the spout is placed in fluid communication with the central portion which is in turn in fluid communication with the hollow stem 3 in such a way as to dispense the fluid contained in the bottle when the dispensing head 13 is pressed by a user.

Preferably, in a configuration illustrated in Figures 2A, 2B, 2C, 2D, the dispensing head 13 comprises protrusions 13a slidably movable resting on the ramp 14a of the retaining ring 14, forming the lifting mechanism described above. Advantageously, the dispenser 1 is able to overcome the drawbacks of the prior art.

Advantageously, by providing a spring made of plastic, the dispenser 1 for dispensing a fluid is easily disposed of and then recyclable with the entire packaging.

Advantageously, the plastic spring, having small dimensions and limited weight, allows the overall aesthetic and dimensional characteristics of the dispensers to be maintained which are similar to the traditional solutions, with a metal spring, already present on the market.

Advantageously, the plastic spring is able to maintain its return capacity over time.

Advantageously, the embodiments of the hollow stem 3 result in greater reliability and better sealing characteristics without adversely affecting production costs and allowing the recovery of existing equipment already made for dispensers with metal springs.

Advantageously, the modules with an interchangeable orientation with which the hollow stem 3 is made allow a reduction in the production costs, given by simple and fast assembly processes with obvious advantages in terms of hourly productivity and the energy needed for producing the dispenser 1.

Advantageously, the dispenser 1 for dispensing a fluid retains all the functional and performance features of the traditional dispensers with a metal spring, both in relation to the protection and the safeguarding of the integrity of the package and the relative contents, and as regards the effectiveness and comfort of use.

Claims

1. A dispenser (1) for dispensing a fluid comprising: a hollow containing body (2) which can be inserted in a bottle, made of plastic material, and comprising at a bottom thereof an orifice for sucking fluid from said bottle, an inlet valve (4), a central portion (2c) defining a dosing chamber (10) and, at a top thereof, a flange (2d) which can be connected resting on the neck of said bottle to guarantee the seal of the liquid contained therein; a ring nut (9) connected or connectable to said neck of the bottle associated with said containing body (2); a piston (6) slidable inside said containing body (2) between a raised position and a lowered position; a hollow stem (3) axially slidable inside said containing body (2) and having at the top a radial protrusion (5b) and at the bottom one or more lateral windows (5a), said hollow stem (3) being associated at the bottom in a slidable fashion with said piston (6) for commanding the opening of said lateral windows (5a) and selectively allowing the passage of the fluid contained in said dosing chamber (10) of said containing body (2); a retaining ring (14) integral with said containing body (2) and inserted therein for housing and guiding the hollow stem (3) and the slidable piston (6) in their stroke inside the containing body (2), said retaining ring (14) also delimiting an upper containment space inside said containing body (2); a concertina-like deformable element (7), inserted inside said upper containment space delimited by the retaining ring (14) and defining a return spring of said dispenser (1), comprising a lateral wall (8) extending between an upper portion and a lower portion of the concertinalike deformable element (7), said lateral wall (8) being coaxial with the hollow stem (3), the upper portion being in contact with the radial protrusion (5b) of the hollow stem (3) and said lower portion being in contact with a lower portion of said retaining ring (14); a dispensing head (13) comprising a central portion connected to an upper portion of said hollow stem (3) to actuate said piston (6) and a spout designed to dispense said fluid contained in said bottle, said dispensing head (13) being able to be pressed by a user between a raised position wherein said lateral wall (8) is axially extended, and a lowered position, wherein said lateral wall (8) is axially compressed; characterised in that said concertina-like deformable element (7) is made of plastic material.

2. The dispenser (1) according to the preceding claim, wherein the retaining ring (14) defines two so-called “rest” positions: a first raised operating position and a second further raised position, relative to said first position, of non-use, or a stop.

3. The dispenser (1) according to claim 2, wherein said first raised operating position is obtained by means of undercuts suitably positioned on the lower portion of the retaining ring (14) against which rest corresponding abutments made on said piston (6), to stop the raising stroke of the piston.

4. The dispenser (1) according to claim 2 or 3, wherein the second non-use position is reached by means of a reciprocal rotation manoeuvre which determines the lifting of said hollow stem (3).

5. The dispenser (1) according to one or more of the preceding claims, comprising a ramp (14a) made on said retaining ring (14) to which are restingly constrained suitable slidable elements made on one of the components integral with the hollow stem (3).

6. The dispenser (1) according to claim 5, comprising a tubular extension (15) connected solidly with the hollow stem (3) by means of snap-on profiles (15b) made on said tubular extension (15) and provided with protrusions (15a) slidably movable resting on the ramp (14a).

7. The dispenser (1) according to claim 5 or 6, wherein said dispensing head (13) comprises protrusions (13a) slidably movable resting on the ramp (14a) of the retaining ring (14).

8. The dispenser (1) according to one or more of the preceding claims, wherein said concertina-like deformable element (7) is made in the form of a spring with a V-shaped profile with a helical and conical extension.

9. The dispenser (1) according to one or more of the preceding claims, wherein said upper portion of the lateral wall (8) of the concertina-like deformable element (7) comprises compensation passages, said compensation passages being configured to allow the entry or exit of air from said concertina- like deformable element (7).

10. The dispenser (1) according to one or more of the preceding claims, wherein said concertina-like deformable element (7) comprises, in said lower portion, a plurality of anti-unscrewing ribs.

11. The dispenser (1) according to one or more of the preceding claims, wherein said hollow stem (3) comprises, at the bottom thereof, a tip (5) hooked thereto by means of a system of undercuts.

12. The dispenser (1) according to claim 11, wherein said tip (5) has at least a window (5a) for the passage of the product to be dispensed contained in the dosing chamber (10) of the containing body (2).

13. The dispenser (1) according to claim 11 or 12, wherein said tip (5) has a conical sealing surface and a widened lower extension designed to facilitate the engagement with the piston (6).

14. The dispenser (1) according to one or more of the preceding claims, wherein the piston (6) comprises a closed connecting surface with a radial extension having a reverse configuration designed to optimise the minimum volume of said dosing chamber (10).

15. The dispenser (1) according to one or more of the preceding claims, wherein the valve (4) is substantially “cup-shaped” and comprises an upper cylindrical surface and a lower spheroidal surface.

16. The dispenser (1) according to one or more of the preceding claims from 1 to 14, wherein said valve (4) has a spherical shape and is made of a plastic material.

17. The dispenser (1) according to one or more of the preceding claims, wherein said ring nut (9) comprises an abutment (11), covering and associated with the flange (2d) of the containing body (2), and a collar (11b) connected thereto, designed to guarantee the hooking between the inner surface of the containing body (2) and the outer surface of the retaining ring (14).

18. The dispenser (1) according to claim 17, wherein said ring nut (9) has, on the abutment (11), a lip (1 la) associated with the tubular extension (15) for achieving a fluid-tight seal.