EP1973667B1

EP1973667B1 - Device for the delivery of gas-liquid mixtures

Info

Publication number: EP1973667B1
Application number: EP07700024A
Authority: EP
Inventors: Stefano Santagiuliana
Original assignee: Taplast SRL
Current assignee: Taplast SRL
Priority date: 2006-01-17
Filing date: 2007-01-04
Publication date: 2009-12-02
Anticipated expiration: 2027-01-04
Also published as: RU2008133414A; CN101370594A; ES2337412T3; ATE450318T1; RU2388549C1; DE602007003557D1; ITVI20060019A1; EP1973667A1; WO2007083206A1; BRPI0707141A2

Abstract

The application concerns a device (1) for the delivery of gas- liquid mixtures in association with a container for a liquid, comprising: first means (2) suitable for being moved from a first resting position to a second position for sucking up said liquid and carrying it to a mixing chamber (3) ; second means (5) suitable for compressing a gas and carrying it into a mixing chamber (3) when the first means (2) are moved from the first position to the second position. Said device also comprises a collection means (6) suitable for collecting at least a part of the portion of liquid in the air-liquid mixture that is not delivered after operating said device and that remains inside said mixing chamber (3) and/or downstream therefrom.

Description

This invention relates to a device for the delivery of gas-liquid mixtures, particularly in association with a container for containing a liquid product for delivery in the form of a foam or nebulized spray.
It is common knowledge that delivery devices are widely used, attached to a container of liquid or cream products, e.g. foodstuffs, soaps, creams, detergent or perfumes, for their delivery in the form of a foam or nebulized spray.
Such manually-operated devices collect the product from the container and mix it with a gas (usually air) under a positive pressure, thereby generating a foam during the delivery stage.
Such devices basically comprise first means for collecting the product from the container and conveying it to a mixing chamber, said first means being operated by means of an actuator in coordination with second means for conveying air entrained from the environment and suitably pressurized to the same mixing chamber.
Said first means essentially comprise a hollow body serving as the product suction/compression chamber, in which a first mobile piston is slidingly engaged. The second means comprise a second piston slidingly engaged in an airtight manner inside a hollow body serving as a gas compression chamber, which communicates with the mixing chamber by means of an air intake pipe.
Means for facilitating the formation of the foam, comprising a filter or porous septum through which the air-product mixture is forced to flow, are installed downstream from the mixing chamber and upstream of the device's outlet.
After the delivery of the product, elastic means ensure the return of the pistons to their resting positions.
In practice, the user takes action on the actuator to load the elastic means and thereby pushes the air under pressure and the product first towards the mixing chamber and then towards the device's outlet.
To be more precise, the air and product are first mixed together in the mixing chamber, forming a mixture that increases in volume as it is forced through the filter or porous septum, giving rise to the required foam.
By releasing the actuator, the user enables the elastic means to restore the device to the initial resting position, ready for a subsequent delivery action.
The first drawback of the known devices lies in that the residual liquid component contained in the foam and in the air-liquid mixture that does not reach the device's outlet tends to drop back into the air compression chamber through the air intake pipe.
A further correlated drawback lies in that the volume of the residual liquid reaching the air compression chamber progressively shrinks, thus altering both the product-to-air ratio and the performance of the device with each delivery action.
It is common knowledge, in fact, that the quality of the foam being delivered depends largely on the ratio of product to air being mixed each time the device is operated.
To overcome at least some of the aforementioned drawbacks, the known state of the art has proposed devices with a one-way valve element inserted inside the air intake pipe to prevent the residual fluid product flowing back into the air compression chamber and to enable the passage of the air.
This gives rise to a disadvantageous increase in the number of the device's component parts, however, with a consequent increase in the manufacturing costs due both to the larger number of components in the device and to the necessary additional operations for the installation of said valve element.
Form Document EP126696 A1 a device is known which comprises collection means adapted to collect residual liquid, said collection means comprising a duct formed in the stem of said device.
Other devices for delivery of gas-liquid mixture are known from US5443569A1 and WO9713585A1 .
Another drawback lies in that, each time the device is operated, said valve element gives rise to a delay in the flow of pressurized air into the mixing chamber due to the valve's inertia.
A further drawback consists in that said valve element makes the device less reliable.
The purpose of the present invention is to overcome the above drawbacks.
A particular object of the invention is to realize a device for the delivery of gas-liquid mixtures, even in the form of a foam or nebulized spray, that presents no variations in the ratio of air to liquid each time the product is delivered.
Another object is to realize a device with minimal overall dimensions by comparison with devices of the known state of the art used in comparable working conditions.
A further object is to realize a device that comprises a smaller number of components than comparable devices of known type.
Another object is to realize a device that is easier to assemble than comparable devices of known type.
A further object is to realize a device that can also be assembled using automated production lines.
Another object is to realize a device that is more compact than comparable devices of known type.
Another, not necessarily last object is to realize a device that is reliable and can also be completely recycled, even without any prior dismantling or other operations.
The above objects are achieved by a device for the delivery of gas-liquid mixtures that can be used in association with a container for a liquid in accordance with the content of the main claim.
Advantageous embodiments form the object of the dependent claims.
The proposed solution advantageously enables the above-mentioned drawbacks to be overcome without using valve elements, thereby reducing both the cost of the device and its complexity, while increasing its reliability and the simplicity of the assembly operations involved, be they undertaken manually or using automatic equipment.
Another advantage of the proposed solution lies in that it enables the realization of a device with minimal overall dimensions, thereby also minimizing the space occupied for the storage of the device-container system and maximizing the amount of product that can be stored inside the container. The aforesaid objects and advantages will become more evident from the description of several preferred embodiments of the invention, provided herein as non-restrictive examples with reference to the attached drawings, wherein:

figure 1 shows a longitudinal section of an example of one embodiment of the device according to the invention, associated with a container for the delivery of a product in the form of a foam;
figure 2 shows another longitudinal section of the device in figure 1;
figure 3 shows the device in figure 1 in a different working position;
figure 4 shows the device in figure 1 in the locked position, when not in use;
figure 5 shows a longitudinal section of another embodiment of the device according to the invention;
figure 6 shows a longitudinal section of another embodiment of the device according to the invention;
figure 7 shows a longitudinal section of another embodiment of the device according to the invention;
figure 8 shows a longitudinal section of another embodiment of the device according to the invention, suitable for delivering a product in nebulized form;
figure 9 shows a top view and a cross-section of a part of the device in figure 8; figures from 10 to 15 each show a longitudinal section of the device in figure 1, in different operating stages;
figure 16 shows a longitudinal section of a further embodiment of the device according to the invention.

First of all, it should be noted that the same parts of the single embodiments are identified by the same reference numbers. Position indicators mentioned in the single embodiments are logically transferable to new positions in the event of any change of position.
The embodiment of the invention described below refers to devices for the delivery of liquid detergents. The proposed solution is clearly also applicable, however, to devices for the delivery of perfumes or foodstuffs, or any other fluid in general, that has to be collected from a container and conveyed towards a delivery point after mixing with a gas, preferably in the form of a foam.
An embodiment of the device for the delivery of gas-liquid mixtures and/or fluids forming the object of the present invention, attached to a container C containing a fluid L for delivery in the form of foam, is illustrated in figure 1, where it is globally identified by the numeral 1.
It comprises first means, indicated globally by the numeral 2, suitable for being moved from a first position at rest, illustrated in figures 1 and 2, to a second position, illustrated in figure 3, where they suck the fluid L (consisting of a liquid detergent in this case) from the container C and carry it first to a mixing chamber 3 and then to the outlet 4 of the device 1 through a delivery pipe 4a.
The device 1. also comprises second means, indicated globally by the numeral 5, suitable for compressing a gas A (consisting of air in this case) and carrying it to the mixing chamber 3, when the first means 2 are moved from the first position to the second position.
According to the invention, the device also comprises collection means, indicated globally by the numeral 6, suitable for collecting at least a part of the portion of liquid of any air-liquid mixture that is not delivered, but remains in said mixing chamber 3 and/or downstream therefrom, and particularly between said chamber 3 and said outlet 4, after the device 1 has been operated.
Again according to the invention, the collection means 6 are also suitable for being emptied, at least partially, during the operation of the device 1, and particularly when the first means 2 are moved from the first position to the second position.
The first means 2, more easily visible in figure 2, comprise a first hollow body 7 in which a first piston 8 is slidingly engaged.
The first hollow body 7 defines a first chamber 9 for the liquid L, also called the suction/compression chamber for the liquid L, which communicates with the inside of the container C by means of a liquid suction pipe 10, and with the mixing chamber 3 by means of at least one liquid intake pipe 11.
The first piston 8 is connected by means of a stem 12 to an actuator 13, also called an actuator cap or button and comprising a spout, whereon the user exerts a pressure to operate the device 1.
The inside of the stem 12 is provided with said liquid intake pipe 11, which communicates with the first chamber 9 and with the mixing chamber 3.
The first piston 8 comprises a supporting element 8a, to which a plunger 8b (also called a membrane) cooperating in an airtight manner with the walls of the first chamber 9, is slidingly engaged.
First and second valve means 14 and 15, arranged downstream and upstream respectively of the suction pipe 10 and the liquid intake pipe 11 regulate the flow of the liquid L from the container C to the first chamber 9 and from the first chamber 9 to the mixing chamber 3.
In the embodiment described herein, the first valve means 14 comprise a first ball 14a made of a nonmetallic material and housed inside a corresponding seat 14b, while the second valve means 15 comprise sealing edges, or lips 15a on the plunger 8b.
The second means 5 comprise at least one second chamber 60 suitable for containing the aforesaid gas A so that when the suction means 2 are moved from the first position to the second position, the gas A is compressed and conveyed to the mixing chamber 3 through an air intake pipe 16.
To be more precise, in the embodiment illustrated herein, the second chamber 60 consists of a second hollow body 17, communicating with the mixing chamber 3 by means of the aforesaid air intake pipe 16, in which a second piston 18 comprising a second plunger 18a is slidingly engaged.
Third valve means, globally indicated by the numeral 19, regulate the replenishment of the air in the second chamber 60, after each delivery action.
In the particular embodiment illustrated herein, said third valve means 19 comprise a ball 19a made of a nonmetallic material and housed in a seat 19b.
It should be noted, moreover, that downstream from the mixing chamber 3 and upstream of the outlet 4 of the device 1 there are also means suitable for contributing to the formation of a foam, globally indicated by the numeral 20.
Said means 20 comprise a filter or a porous septum 20a and a diaphragm 20b with a plurality of through holes 21. There is a gap between the porous septum 20a and diaphragm 20b, that together constitute an expansion chamber 22 that facilitates the mixing of the liquid L with the air A, and the formation of a foam. The collection means 6 comprise a collection tank 25 coming between the second means 5 and the mixing chamber; to be more precise, said collection means are situated inside the pressurized gas intake pipe 16 that, as mentioned earlier, places the second means 5 in communication with the mixing chamber 3.
To be more specific, the top of the tank 25 communicates with the second air compression chamber 60 through a first stretch of the pressurized air intake pipe 16, while at the bottom it is complete with at least one opening 26 communicating, through a second stretch of the pressurized air intake pipe, with the mixing chamber 3.
In the embodiment illustrated, the tank 25 is in the shape of a ring arranged coaxially both to the stem 12 of the first piston 8 and to the plunger 18a of the second piston 18. To be more precise, the tank 25 is contained between two cylindrical walls 25a and 25b forming part of the second plunger 18a.
Again according to the invention, the capacity of the tank 25 is equal to or greater than the volume of the residual liquid obtained after the mixture contained inside the mixing chamber 3 and/or the expansion chamber 22 and/or the outlet pipe 4a has dissolved, said quantity of liquid depending on the air to liquid ratio of the mixture.
According to another embodiment of the invention, the capacity of the tank 25 is equal to or greater than the volume of the outlet pipe extending downstream from the mixing chamber to the device's outlet.
To be more precise, the capacity of the tank is equal to or greater than the sum of the volumes of the mixing chamber 3, the expansion chamber 22 and the outlet pipe 4a.
It should be noted, moreover, that in the preferred embodiment, the collection means 6 are situated outside the second chamber 60. This advantageously enables the useful volume of the air compression chamber 60 to remain the same, optimizing the overall dimensions of the device. This solution also enables a reduction in the volume of the outlet pipe and a consequent reduction in the amount of residual liquid that can remain inside said pipe after each delivery action.
It should also be noted that in other embodiments the opening 26 may not be in the bottom of the container.
The device 1 also comprises elastic means, indicated globally by the numeral 28, suitable for ensuring the return of the means 2 and 5 to the first position after a delivery action.
To be more precise, in the embodiment illustrated, these elastic means 28 comprise a helical spring 28a situated inside the second chamber 60 for the compression of the gas A.
To be more specific, said helical spring 28a has one end coming to bear on the second piston and the other end coming to bear on the bottom wall of the second chamber 60.
The device 1 also comprises means for locking/releasing the device 1, indicated globally by the numeral 29 and visible in figure 4.
Said means 29 are suitable for preventing or enabling the operation of the device 1 and can be operated by selectively rotating the actuator element 13 around a longitudinal axis, from a first predefined locking position, shown in figure 4, to a second predefined operating position, shown in figures 1, 2 and 3.
These means comprise a first opposing element consisting of a first projecting part 29a solidly attached to the stem 12, shown in figure 4, suitable for selectively interfering with a second opposing element 31 belonging to the supporting element 32 and solidly attached to the first hollow body 7.
In the case in point, this second opposing element 31 comprises a horizontal striker plane 31a that interferes with the element 29a, thereby preventing the axial movement of the plunger-stem-actuator assembly. The horizontal striker plane 31a is interrupted by a vertical groove 34, not shown in figure 2, obtained in the ring-shaped element 32, whereon the projecting element 29a can slide under the pressure exerted by the user to enable the movement of the pistons 28, 8 when the actuator 13 is brought into the releasing position.
Another embodiment of the invention, globally indicated with the numeral 100 in figure 5, is distinguishable from the previous embodiment in that the third valve means 19 comprise a ring-shaped lip 38 made of a nonmetallic material and belonging to a membrane 18b that forms part of the plunger of the first piston 18.
A further embodiment of the invention, indicated globally by the numeral 101 in figure 6, is distinguishable from the previous embodiment in that the ring-shaped lip 38a consists of a separate element associated with the membrane 18b on the plunger of the first piston 18.
Another embodiment of the device according to the invention, indicated globally by the numeral 102 in figure 7, is distinguishable from the previous embodiment in that the second chamber 60 is collapsible and, to be more specific, consists of bellows 39.
Said embodiment is also distinguishable from the previous embodiments in that, in addition to forming at least a part of the air compression chamber 60, said bellows 39 are elastic bellows that also serve as elastic means 28 for enabling the device to return to the resting position after each delivery action.
Clearly, however, in other embodiments, the first chamber 9 may also be collapsible and the elastic means 28 may also be situated inside the first chamber 9.
Another embodiment, not illustrated herein, is distinguishable from the previous embodiments in that the device also comprises means suitable for varying the allowable stroke of the first means 2.
This advantageously enables a variation in the quantity of foam delivered, while maintaining a constant air-to-liquid ratio. These means comprise an opposing element suitable for selectively engaging in grooves of various length provided, for instance, in the supporting element 31.
In this case, before operating the device, the user turns the actuator 13 into the position corresponding to the quantity of fluid to deliver, which is suitably indicated on the cap.
Another embodiment of the invention, indicated globally by the numeral 103 in figure 8, is distinguishable from the previous embodiments in that the device delivers the liquid product in nebulized form.
For said purpose, the means 20 are suitable for contributing to the nebulization of the product and in this case comprise a nozzle 65, illustrated in detail in figure 9. Said nozzle 65 is complete with three lines 66, which carry the air-product mixture towards the outlet 65b of the nozzle 65, generating a turbulence that determines the nebulization of the mixture.
Another embodiment of the invention, indicated globally with the numeral 104 in figure 16, is distinguishable from the previous embodiments in that the collection means 6 consist of a stretch 70 of the air intake pipe 16 and, to be more precise, of a stretch wherein said pipe has a wider cross-section.
Clearly, all the valve means in the device as described hitherto may be substituted by any other equivalent valve means of known type, and the same applies to the locking and stroke-limiting systems of the suction means.
The operation of the device according to the invention is described below, with reference to a system for the delivery of gas-liquid mixtures comprising a container C for a liquid L and a device 1 of the type illustrated in figure 1, given that there are no substantial differences between this and the other devices illustrated in figures 5, 6, 7 and 8.
In practice, the user takes preliminary action on the actuator 13, rotating it in order to configure the device 1 in the required operating mode.
To be more specific, the user can lock the device 1 by rotating the spout or cap 13 around its axis 30 so as to bring it into the position shown in detail in figure 4: in this position, the first opposing elements 29a face the striker planes 31 a, thus preventing any axial movement of the first and second means 2 and 5.
Vice versa, to operate the device 1, the user rotates the actuator 13 around its axis 30 in order to bring it into the position shown in figure 1: in this position, the former opposing elements 29a face the groove 34, along which they are able to slide freely, thus enabling the pistons 8 and 18 to move axially under the pressure P exerted by the user on the actuator 13.
In so doing, the user loads the elastic means 28 and compresses both the product L contained in the first chamber 9 and the air contained in the second chamber 60.
The rise in the pressure in the first chamber moves the plunger 8b on the supporting element 8a, thus enabling the liquid L contained in the chamber 9 to flow out, first into the liquid intake pipe 11 and then into the mixing chamber 3, along the path indicated by the numeral 50 in figure 10.
At the same time and in the same way, the increase in the pressure in the second chamber 60 forces the pressurized air first into the air intake pipe 16 and then into the mixing chamber 3, along the path indicated with the numeral 51.
The mixture that forms inside the mixing chamber 3 then moves to the outlet 4, passing through the means 20.
To be more specific, the liquid-air mixture passes first through the holes 21 in the diaphragm 20b, giving rise to a turbulence that facilitates the creation of air bubbles in the mixture, which subsequently expands in the expansion chamber 22 and passes through the filter 20a, where it becomes finer, ultimately reaching the outlet 4 through the pipe 4a in the form of a foam F, as shown in figures 3 and 11.
When the actuator 13 reaches the bottom of the first chamber 9, as shown in figure 11, it is released by the user, thus enabling the elastic means 28 to restore it to the initial resting position illustrated in figure 1.
This elastic return generates a negative pressure inside the chambers 9 and 60.
This negative pressure prompts the intervention of the first and second valve means 14 and 15 and makes the liquid L flow into the first chamber 9, making the device ready for subsequent reuse. To be more precise, the negative pressure retains the first plunger 8b which slides along the supporting element 8a and thus closes the liquid intake pipe 11, as illustrated in detail in figure 12.
At the same time and in the same way, the negative pressure generated in the second chamber 60 prompts the intervention of the third valve means 19, which consequently enable air to flow from the outside E into the first chamber 5, preparing the device 1 for subsequent reuse.
As shown in figure 13, on completion of a delivery operation, a residual amount of air-liquid mixture and/or foam that has not been delivered remains inside the outlet pipe 4a, the means 20 and the mixing chamber 3.
With time, the liquid and gaseous components of the mixture become separated. This means that, due to gravity, the residual liquid part drops into the mixing chamber and then, through the air intake pipe 16, reaches the tank 25, as shown in figure 14, thereby emptying the outlet pipe 4a and the means 20.
The residual liquid L thus collects temporarily in the tank 25, advantageously avoiding it reaching the second chamber 60.
It should be noted, moreover, that the proposed solution means that, when the device is subsequently reused, the tank 25 is emptied and all or most of the liquid it contained is carried into the mixing chamber 3. This advantageously enables the recovery of the liquid L in the tank 25, returning it to the mixing chamber 3 and consequently to the device's outlet 4, thereby substantially avoiding any loss of liquid.
In fact, a subsequent operation of the device determines a flow of pressurized air into the tank 25 through the first stretch of the air intake pipe 16.
When the pressurized air arrives above the surface of the liquid L inside the tank 25, it forces said liquid L towards the opening 26 in the bottom of the tank 25, thereby progressively emptying the tank, as shown in figure 13, and delivering air into the mixing chamber 3.
From the above description, it is clear that the proposed solution enables the previously-mentioned drawbacks to be overcome.
In particular, the proposed solution advantageously enables a device to be obtained that contains a smaller number of valve elements than comparable devices of the known state of the art.
It should also be noted that the proposed device can advantageously and preferably also be made entirely of plastic or synthetic material. This gives rise to a device that can be completely recycled without any prior action being needed to separate any parts made of metal or other incompatible materials.
Another advantage lies in that, by preventing the liquid from reaching the chamber, the proposed solution enables the spring to be advantageously installed inside said compression chamber, a solution that would otherwise not be advisable because of the oxidation phenomena that would be bound to occur therein as a result of contact between the metal, the liquid and the air, leading to a discoloring of the liquid being delivered.
Even though the invention has been described with reference to the attached to drawings, it may undergo some modifications during the executive stages, all coming within the same inventive concept expressed in the following claims and consequently covered by the present patent.
It should also be noted that, where the characteristics stated in the following claims are followed by reference signs, these signs shall be intended merely for the purpose of facilitating the reader of the claims and shall not restrict their interpretation in any way.

Claims

Device (1, 100, 10 1, 102, 103) for the delivery of gas-liquid mixtures in association with a container (C) for a liquid (L), comprising:
- first means (2) suitable for being moved from at least one first resting position to at least one second position for sucking up said liquid (L) and carrying it to at least one mixing chamber (3);

- second means (5) suitable for compressing a gas (A) and carrying it into said at least one mixing chamber (3) when said first means (2) are moved from said at least one first position to said at least one second position;

- said device comprising collection means (6) suitable for collecting at least a part of the portion of liquid (L) in the air-liquid mixture that is not delivered after operating said device and that remains inside said mixing chamber (3) and/or downstream therefrom, said collection means (6) communicating with said at least one mixing chamber (3) and with said second means so as to be adapted to be at least partially emptied during a subsequent operation of said device, when said first means (2) are moved from said at least one first position to said at least one second position, so that, during the emptying of said collection means, the liquid contained therein is at least partially carried into said mixing chamber;
characterized in that, said collection means (6) comprise a tank (25) having the shape of a ring defined by two cylindrical walls (25a, 25b) forming part of a plunger (18a) belonging to said second means (5) and adapted to compress said gas (A) so as to carry it into said at least one mixing chamber (3).
Device according to claim 1, characterized in that said tank (25) comprise at least one stretch (70) of an air intake pipe (16) that places said second means in communication with said at least one mixing chamber. (3).
Device according to claim 2), characterized in that said at least one stretch has a wider cross-section than the cross-section of the remainder of said air intake pipe (16).
Device according to any of the claims from 1) to 3), characterized in that said tank (25) communicates with said second means and is provided with at least one opening communicating with said mixing chamber.
Device according to claim 4), characterized in that said at least one opening is provided basically in the bottom of said tank.
Device according to claim 4) or 5), characterized in that said tank communicates with said second means by means of a gas intake pipe situated in the upper part of said tank, above the surface of the liquid (L) collecting in said tank.
Device according to any of the previous claims, characterized in that the capacity of said tank (25) is equal to or greater than the volume of the residual liquid obtained after the mixture in said mixing chamber (3) and/or in an expansion chamber (22) and/or in an outlet pipe (4a) has dissolved.
Device according to any of the previous claims, characterized in that said first means (2) comprise a first hollow body (7), forming a chamber (9) for the liquid to mix and communicating with said container by means of a suction pipe (10), and a first piston (8) slidingly engaged in said first hollow body.
Device according to any of the claims from 1) to 8), characterized in that said first means (2) comprise a first collapsible chamber for the liquid to mix communicating with said container by means of a suction pipe (10).
Device according to any of the claims from 8) to 9), characterized in that said device also comprises first and second valve means (14, 15) suitable for regulating the flow of said liquid from said container to said chamber (9) and its flow therefrom into said at least one mixing chamber (3).
Device according to claim 10), characterized in that said first and/or second valve means (14,15) comprise a ball (14a) and/or sealing edges or lips (15a).
Device according to any of the previous claims, characterized in that said second means (5) comprise at least one second hollow body (17), suitable for defining a second chamber (60) for the gas to mix and communicating with said at least one mixing chamber (3) by means of at least one gas intake pipe (16), with a second piston (18) slidingly engaged in said second hollow body (17).
Device according to any of the claims from 1) to 9), characterized in that said second means (5) comprise at least one second collapsible chamber communicating with said at least one mixing chamber (3) by means of at least one gas intake pipe (16).
Device according to claim 12) or 13), characterized in that said device also comprises third valve means (19) suitable for regulating the flow of gas into said at least one second chamber (60) and its flow therefrom into said at least one mixing chamber (3).
Device according to claim 14), characterized in that said third valve means (19) comprise a second ball (19a) and/or sealing lips (38, 38a).
Device according to any of the previous claims, characterized in that said device also comprises elastic means (28) suitable for ensuring the return of said first means (2) and/or of said second means (5) to the first position after a delivery action.
Device according to claim 16), characterized in that said elastic means comprise at least one elastic bellows element (39) or at least one helical spring (28a).
Device according to any of the previous claims, characterized in that said device also comprises means for locking/releasing (29) said first means (2) and/or said second means (5) so as to prevent or enable the operation of said device, said means for locking/releasing said first and/or said second means preferably can be operated by the user by selectively rotating an actuator (13) integral with a stem (12) of said first piston (8).
Device according to claim 18), characterized in that said locking/releasing means comprise a first element (29a) projecting from said stem (12) so as to interfere selectively with a second opposing element (31 a) or to slidingly engage in one or more groove(s) (34).
Device according to any of the previous claims, characterized in that said device also comprises means (20) suitable for contributing to the formation of a foam (F) installed downstream from said at least one mixing chamber (3) and upstream of an outlet (4) of said device or means (20) suitable for contributing to the nebulization of the mixture, installed downstream from said at least one mixing chamber (3) and upstream of an outlet (4) of said device.
System for the delivery of gas-liquid mixtures, comprising a container for a liquid and a delivery device characterized in that said delivery device is realized according to any of the previous claims.