WO1997036801A2

WO1997036801A2 - Method and apparatus for maintaining and generating a pressure within a product dispenser

Info

Publication number: WO1997036801A2
Application number: PCT/BE1997/000039
Authority: WO
Inventors: Raymond Leonard Housen
Original assignee: Belgium Spray Accessory Factory Naamloze Vennootschap
Priority date: 1996-04-02
Filing date: 1997-04-01
Publication date: 1997-10-09
Also published as: BE1010074A6; EP0892747A2; JP2000507530A; AU2281997A; CA2250752A1; WO1997036801A3

Abstract

Method for generating pressure in a spray can and the like, whereby at least two products (8-9) are brought into contact with each other such, that, by doing so, a gas is produced and, thereby, a gas pressure is created, characterized in that the products (8-9) are brought together via a passage (12), whereby the flow rate via this passage (12) is controlled by means of a movable element (18-50-56-68) which, in its turn, is controlled by the gas pressure prevailing around the device.

Description

METHOD AND APPARATUS FOR MAINTAINING AND GENERATING A PRESSURE WITHIN A PRODUCTDISPENSER

This invention refers to a method and a device for generating pressure in a spray can and the like, as well as to a spray can equipped with such device.

More particularly, it refers to a method for generating pressure of the type whereby at least two products are brought into contact with each other in such a way that, by doing so, a gas is produced and, thereby, a gas pressure is created.

According to a known technique which is described in the European Patent No. 0 033 377, the aforementioned products are stocked in different compartments of a pouch. After installing this pouch in a spray can, the products, by subsequently breaking the partition walls between the aforementioned compartments, are brought into contact with each other, as a result of which a gas is created in the pouch, expanding this pouch. The expansion of the pouch is used to dispense the product present in the spray can, as well as for systematically breaking the partition walls of the subsequent compartments.

This technique shows as a less favourable characteristic that the pressure in the spray can is not constant, but fluctuates. Each time two compartments are connected to each other, a gas production occurs which causes a press¬ ure increase. The two subsequent compartments are only connected to each other as soon as the pouch has realized a definite expansion, whereby the pressure, however, is reduced. Taking into account that the number of compart- ments is limited due to constructive causes, the afore¬ mentioned pressure fluctuations are relatively large. This known technique also shows the disadvantage that the pouch with the compartments has to be assembled quite accurately in order to let the partitions between the compartments break at the right moments.

The invention aims at a method and device with which one or more of the aforementioned disadvantages can be excluded.

To this aim, the invention, first of all, concerns a method for generating pressure in a spray can, whereby at least two products are brought into contact with each other in such a way that, by doing so, a gas is produced and, thereby, a gas pressure is created, with the characteristic that the products are brought together via a passage, whereby the flow rate via this passage is commanded by means of a movable element which, in its turn, is controlled by the gas pressure prevailing around the device.

According to a preferred form of embodiment, the flow rate of the passage is regulated by means of a pressure- reactive regulator, more particularly a pressure-reactive valve reacting progressively onto the pressure in the spray can, such that the passage is closed every time the pressure in the spray can has obtained a well-defined value, but is reopened as soon as the pressure decreases below the aforementioned value.

Hereby is obtained that the two products are brought together progressively, whereby the gas production occurs precisely in function of the quantity of gas necessary to restore the normal dispensing pressure after each activation of the spray can.

According to a variant which offers the advantage that it can be realized with a considerably cheaper installation, the passage is closed initially and, by means of the moving element, a remaining passage is created once, as a result of which the products concerned react completely.

The invention also refers to a device for the realization of the aforementioned method. To this aim, it consists of a receptacle wherein a first of aforementioned two products is available; a closable or closed passage via which, by means of opening or realizing an open passage, the first product and the second product can be brought into contact with each other; and a movable element which can be controlled by means of the pressure surrounding the device and which performs the opening, and eventually closing, of the passage, respectively the production of such a passage.

The first product preferably is a liquid, εo that, for the movable element, use can be made of a valve. This valve provides in that the liquid can leave the receptacle and come into contact with the second product.

The expulsion of the liquid from the aforementioned receptacle, at least in the open position of the valve, can be performed in different manners. According to an advantageous possibility of the invention, the device comprises means which allow for placing the liquid under pressure in the receptacle, assisted by the pressure which is created in the spray can, such that no separate pressure means for the expulsion of the liquid are necessary. In a preferred form of embodiment, these means are formed by a wall of the aforementioned receptacle which, to this aim, is manufactured from a slowly gas- permeable material.

The products which are brought into contact with each other via the passage can be the products which react with each other for the production of a gas, but may also be products which do not react with each other, but provoke a reaction.

According to a first interesting possibility, the first product consists of a liquid acid, whereas the second product consists of salt in solid condition.

According to a second interesting possibility which offers the advantage that no liquid acid has to be handled, the first product consists of a dissolvent, for example water, and the second product consists of a dry composition of an acid and a salt, such, that a reaction with formation of a gas will be performed only when the acid and/or salt comes into dissolved condition by adding the first product to the second product.

In a preferred form of embodiment, the device is equipped with a pressure-reactive flow regulator which is manufac¬ tured in such a way that the passage is closed as soon as the pressure reaches a value which is higher than or equal to the dispensing pressure of the spray can for which the device is intended, and is closed at least also at a pressure which is smaller than or equal to atmos¬ pheric pressure. As a result of this, the device can simply be stored in an atmospheric environment before being installed in a spray can, without the gas generation starting. Furthermore, the device can simply be activated by initially creating a pressure in the container of the spray can in an external manner.

The invention also refers to a device for generating pressure in a spray can, whereby at least two products are brought into contact with each other such, that, by doing so, a gas is produced and, thereby, a gas pressure is created, characterized in that the first product consists of a dissolvent and the second product consists of a dry composition of salt and an acid, preferably in the shape of a block of compressed powder, regardless of the manner in which these products are brought together.

In order to better show the characteristics of the invention, by means of example without any limitative character, several preferred forms of embodiment are described in the following, with reference to the accompanying drawings, wherein:

figure 1 schematically shows a spray can equipped with a device according to the invention; figure 2 shows a practical form of embodiment; figure 3, on a larger scale and in cross-section, shows the part which is indicated by arrow F3 in figure 2; figure 4 shows a cross-section according to line IV- IV in figure 3; figures 5, 6 and 7, on a larger scale, show the part which is indicated by F5 in figure 3, for different positions; figure 8 shows an alternative of the part which is indicated by F8 in figure 3; figure 9, in cross-section, shows a variant of a device according to the invention; figures 10 and 11, on a larger scale and for different positions, show the part which iε indicated by F10 in figure 9; figures 12 and 13 show the bottom part of another two variants; figureε 14 to 16 show the device from figure 13 in different positions; figures 17 and 18 show another device according to the invention, for two different positions; figures 19 to 21 show a further form of embodiment, also for different positions.

As shown in figure 1, the invention refers to a device l which can be installed in a spray can 2, allowing to create an excess pressure P in the container 3 of the spray can 2, such that the product 4 to be dispensed, present in the spray can, is expelled from the container 3, for example, by means of a dip tube 5, as soon as the usual valve 6 or similar is activated, more particularly, is opened by means of pressing a push-button 7.

According to the form of embodiment shown schematically in figure 1, use is made of two products 8 and 9 reacting to a gas 10 when brought together. Preferably products are used reacting mutually to the formation of carbon dioxide gas. The first product 8 to this end preferably consists of an acid in liquid condition, or of an acid dissolved in a liquid, for example, citric acid. The second product 9 preferably consists of a salt, for example, calcium carbonate, barium carbonate, or sodium bicarbonate.

As represented, the device 1 for the generation of the gas 10 substantially consists of a receptacle ll wherein the first product 8 is situated; a passage 12 via which the first product 8 can come into contact with the second product 9; and a pressure-reactive flow regulator 13, with a movable element, such as a close-off valve, with which the passage 12, in function of the surrounding pressure around the device 1, thus, of the pressure in the container 3, is closed-off or not.

The pressure-reactive flow regulator 13, in this case, is of such nature that the passage 12 is closed-off as soon as the value of the pressure in the container 3 is higher t_han or equal to a pre-defined value, and is reopened as soon as a pressure decrease occurs in the container 3.

Here_by, the aforementioned pre-defined value is equal to the necessary dispenεing pressure.

_Actually, the aforementioned products 8 and 9 must not each be placed within a receptacle. It is, however, sufficient that they are separated from each other and they can be brought together in a controlled manner by means of the pressure-reactive flow regulator. Principally, one of the two products, in this case, product 9, may be present freely in the container 3 of the spray can.

The functioning and use of the device 1 are substantially as follows.

In non-operative condition, the container 3 is filled with a defined quantity of product 4 to be dispensed and a quantity of gas 10 with which the container 3 is held under a pressure P. When pressing the push-button 7, the valve 6 is opened and the product 4, via dip tube 5 and a dispensing opening 14, is expelled outwards and eventual¬ ly atomized. As a result of this, the pressure in the container 3 decreases. The pressure decrease is percepted by the pressure-reactive flow regulator 13 which hereby opens the passage 12. As a result of this, the product 8 from the receptacle 12 comes into contact with product 9, which causes the generation of gas 10 and the restoration of pressure P.

As soon as the pressure P has reached its normal value, the flow regulator 13 closes the passage 12 again. The supply of product 8 to product 9 is thus interrupted, as a result of which the gas production is stopped and the pressure in container 3 does not increase any more. In order to expel the product 8 from the receptacle 11, according to the invention different techniques may be employed.

According to one possibility, the receptacle 11 is set under pressure by providing therein, along with the product 8, also a quantity of gas under pressure, with a pressure that is preferably higher than the dispensing pressure of the spray can.

In the figures 2 to 7, a practical form of embodiment of the device 1 is shown.

Here, the second product 9 is placed in a chamber 15 which connects to the aforementioned passage 12, which offers the advantage that the product 8, flowing out of the passage, directly comes into contact with product 9, which guarantees an immediate reaction. The generated gas 10 can leave the chamber 15 via outlet openings 16.

The pressure-reactive flow regulator 13 consists of a pressure-reactive element 17 and a movable element cooperating with it, more particularly a valve 18, which is mounted in the passage 12.

The pressure-reactive element 17 can principally consist of any elastically compressible construction. In the given example, it consists of a housing 19, one wall of which is formed by a diaphragm 20, which can be moved under the influence of the pressure present in the spray can and consists, for example, of a thin corrugated steel plate. The reaction force during indentation of the diaphrag a 20 is substantially delivered by means of an elastic element 21 which is enclosed in the housing 19.

It is clear that the housing 19 is gas-tight. The gas present in the housing 19, for example, air under atmospheric pressure, and the elasticity of the diaphragm 20 of course also provide a force component exerting an influence upon the displacement of the diaphragm 20.

In a form of embodiment which is particularly simple to realize, the elastic element 21 is to be formed by a piece of rubber or plastic tube which, in compressed condition, is to be enclosed into the housing 19 either straight or in wou.d-up condition.

The valve 18 preferably consists of a needle-shaped valve body 22 wherein a recess 23 is provided, and a valve seat 24 in which the valve body 22 can shift axially such, that the passage 12 is open when the recess 23 is located in front of valve seat 24.

Herein, the valve seat 24 can consist of an O-ring mounted in the pasεage 12.

The valve body 22 at one end cooperates with the diaphragm 20 and can be fixed to it or not.

In the form of embodiment of figure 3 , the receptacle 11 has a wall 25 which is manufactured from a material allowing a slow permeation of gas under application of a pressure difference. This wall 25 must not be permeable for all gases, it is sufficient that it is permeable for the produced gas 10, first of all for carbon dioxide.

More particularly, this wall 25 shall consist of semi¬ rigid material, for example polyurethane.

In order to obtain a sufficient permeability, the wall 25 shall be manufactured relatively thin, for example, by means of a thermo-forming process. In order to give it nevertheless sufficient stability it may be provided with steps.

The configuration of the receptacle 11, the chamber 15 and the housing 19 is preferably as shown in figure 3, which means that the chamber 15 is situated between the receptacle 11 and the housing 19, that the valve 18 is arranged in the wall 26 between the receptacle 11 and the chamber 15 and that the diaphragm 20 is situated opposite to the wall 26 wherein the valve 18 is arranged. The product 9 is preferably formed by a ring-shaped block of compressed salt, which is positioned around the valve body 22.

The functioning of device 1 is as described hereafter.

When the device 1 is in an atmospheric surrounding, the valve body 22 assumes a position as shown in figure 5, because the diaphragm 20 bulges upward. By this, the passage 12 is closed and the first product 8 cannot leave the receptacle 11.

After the device 1 being installed in a spray can 2, first of all, via an external supply, in the spray can 2 a pressure can be applied which, for example, is somewhat higher than the normal dispensing pressure. This pressure effects onto the diaphragm 20, by which the valve body 22 shifts up to the position shown in figure 6.

Taking into account that the wall 25 is gas-permeable, a pressure is also built up in the space 27 of the receptacle 11. After a while, the pressures in the container 3 and in the space 27 equal each other.

When product 4 subsequently is dispensed, the pressure in the container 3 decreases. This pressure decrease, however, is not immediately followed by a similar pressure decrease in the space 27. When the pressure in the container 3 is reduced under the normal dispensing pressure, the valve body 22 obtains a position as shown in figure 7. Taking into account that the pressure in the space 27 at that moment is higher than in the container 3, the product 8 is expelled from the receptacle 11 via the opened valve 18.

As a result of the reaction of the released product 8 with product 9, gas is produced which, via the outlet openings 16, comes into the container 3. Hereby, the pressure increases again, causing the diaphragm 20 to be indented again. When the desired dispensing pressure is obtained, the diaphragm 20 is indented such, that the condition of figure 6 is reached again, whereby the passage 12 is closed and the gas generation stops.

It is clear that in this manner a constant pressure is maintained automatically in the container 3.

Instead of a permeable wall 25, preεεure paεsage means of another type can be applied. According to an alternative, the wall 25 is not permeable for gas and, as sche atic- ally shown in figure 3, a return valve 28 is applied allowing that the gas 10 from the container 3 can flow into the receptacle 11 when the pressure in the container 3 is higher than the pressure in the receptacle 11.

Of course, still other forms of embodiment are possible. In figure 8, for example, a variant is shown whereby the elastic element 21 consists of a ring-shaped block from elastically compressible material, for example, foam plastic or rubber.

According to a not represented variant, no elastic element 21 will be used, and the reactive force is only delivered by the the own elasticity of the diaphragm 20 and the gas pressure exerted thereon.

Figure 8 also shows that the valve body 22 may be fixed to the diaphragm 20, in this case by clamping in a seat 29 in the center of the diaphragm.

As also shown in figure 8, each of the outlet openings 16 can be provided with a return valve 30. This may consist of an elastic band which is stretched over the outlet openings with very little tensioning force, such as, for example, the shown O-ring 31.

Because of the presence of the return valve 30, the generated gas 10 can escape, the products 4 and 9 , however, can not come into direct contact with each other which can be desirable in certain applications. In this manner, the product 9 also cannot spread itself in the container 3, for example, by solution in product 4. Hereby, the not yet reacted product 9 remains in the proximity of the passage 12 so that the release of a quantity of product 8 always results in an immediate generation of gas.

Such a return valve can also consist of a very small opening or a porous part in the wall of chamber 15, whereby this opening of this porous part allow that gas 10 can leave the chamber 15, but no liquid can penetrate in the opposite direction.

In figure 9, a form of embodiment is represented whereby the second product 9 consists of a composition of components which, in undissolved condition, do not react with each other, in dissolved condition, however, will react with each other, whereas the first product 8 is formed by a dissolvent, for example water, with which one or both of the aforementioned components can be dissolved.

The device 1 shows a similar construction as the embodiment from figure 8. Conforming parts, then, are indicated with the same references.

Instead of the receptacle 11 being filled with a liquid acid, it is now filled with a dissolvent, preferably water.

The product 9 preferably consists of a mixture of dry components which will react with each other when being dissolved in a liquid, more particularly in the product 8. More particularly is preferred that these components are compressed to a single block or similar. Hereby, the components can consist of a salt, on one hand, and an acid in dry condition, for example in the shape of grains and/or powder, on the other hand.

The device 1 from figure 8 is, analogous to the embodiments from figures 3 to 8, provided with a valve 18 which is controlled by means of a pressure-reactive element 17.

The pressure-reactive element 17, in this case, is formed by a compressible housing 19 which is not connected to the chamber 15 and consists of two metal diaphragmas 32- 33 which enclose a space 34 and are welded together by their edges.

In figure 9, exclusively as an example, a valve 18 is shown the design of which differs from the one shown in figure 3. The valve 18 shows a needle-shaped valve body

22 which fits through the passage 12 and which is provided with two closing members 35-36 which can cooperate with two valve seats 37-38, such, that a closure is obtained when the valve body is pushed either into the one extreme position or into the other extreme position, and such, that a passage is obtained when the valve body takes a position situated between these two extreme positions.

In the represented example, the closing members 35-36 consist of enlargements in the valve body 22 , whereas the valve seats 37-38 are formed by the edges, situated at opposite sides of the wall 26, of the passage 12 provided in this wall 26. Between the closing members 35- 36, recesses 39 can be provided in the valve body 22 in order to render the passage of liquid in the open position of the valve more easily.

In the embodiment of figure 9, the valve body 22 is loaded by means of an elastic element, such as a bow 40, which provides for that the valve body 22 does not get off the pressure-reactive element 17.

To a great extent, the working is analogous to the one of the aforementioned forms of embodiment and will be described step-wise in the following, in reference to figures 9 to 11.

In figure 9, the device 1 is subject to atmosperic conditions. The pressure delivered by element 17, hereby, is such that the valve body 22 is pushed upward and a sealing of the passage 12 is obtained because the closing member 36 becomes situated against the valve seat 38.

When the device is situated in a spray can 2 and the latter is initially activated by realization, via the external way, of a gas pressure, the pressure-reactive element 17 is pushed inwardly, the valve body 22 is shifted, and the passage 12 is closed off, in this case, because the closing member 36 becomes situated upon valve seat 37, as shown in figure 10.

When the pressure in the container 3 of the spray can 2 diminishes, because product 4 is dispensed, the pressure in the chamber 15 will also diminish, as a result of which the presεure-reactive element 17 enlarges and the valve body 22 comes into a position as shown in figure 11, as a result of which the product 8, in this case water, flows via passage 12 into the chamber 15, under influence of the pressure which prevails in the space 27 and which develops in the same manner as described in reference to figure 3.

Because the water comes into contact with the mixture of acid and salt, one or both of these components will dissolve and they will react with each other, as a result of which gas develops and a pressure increase is created in the chamber 15 and, thereby, also in the container 3. With the increase of this pressure, the pressure-reactive element 17 is compressed again, and, when a defined pressure is reached, the valve body 22 comes back into the position of figure 10, whereby the supply of water is interrupted and, as a result of this, also the aforementioned reaction is terminated.

In consideration of the fact that with certain reactions of this kind, sometimes water is produced, it may be necessary to add still further substances to the product 9 in order to prevent the development of a chain reaction. This can easily be determined from the respective reaction comparisons as well as in an empiric manner. When the device 1 from figure 9 is meant to be applied in a product 4 which also forms a dissolvent for the components of which the product 9 consists, the openings 16 will have to be provided with a return valve 30, such as, for example, an elastic band 41. In this case, however, measures will have to be met in order to achieve that the chamber 15 can be pressurized by the initial pressurization of the container 3.

In figure 12, a variant is shown whereby the passage 12 partially is formed by a hollow 42 in the valve body 22. This hollow 42 gives out into the receptacle 11. In the wall surrounding the hollow, a radial opening 44 is provided which, by the movement of the valve body 22, is either situated opposite to a wall part 45 or opposite to a wall part 46 or opposite to an opening 47 giving out into chamber 15, whereby a sealing is obtained in the first two cases. The functioning of the embodiment from figure 12 can be compared to the one from figure 9.

In figures 13 to 16, a form of embodiment is represented with which a single generation of gas is provided. This device which can be called a "One Shot" gas generator, provides for that after half of the lifetime of a spray can, the pressure in this spray can is increased again. The pressure in the spray can, thus, is not constant, but due to the fact that a pressure-reactive movable element, such as a valve, is used, the advantage is obtained that the moment in which the gas will be generated additionally, can be defined very precisely in function of the pressure in the spray can, which is not the case with the known devices using a pouch with compartments whereby the partition walls are broken down by destructing them.

As shown in the figures 13 to 16, the device 1 uses a motion system 48 which is basically formed by a wall part 49 in the shape of a diaphragm which delimits the chamber 15 and, by means of a well-defined pressure difference, can switch from position A to B and vice versa.

The motion system 48 cooperates with a movable element with which the passage 12 can be closed off, respectively opened, which, in this case, consists of a closing element, such as a valve 50. This valve 50 shows a closing portion 51 which can be drawn downward out of the passage 12, but which, however, by means of an abat ent portion 52, is prevented from slipping out of the passage 12.

Furthermore, in the form of embodiment of figures 13 to 16, coupling means 53 are provided which allow for coupling the wall portion 49 to the valve 50. These coupling means 53 consist in the represented example of a snap-on coupling with hook-shaped coupling parts 54 which can engage behind a coupling part 55.

The functioning of the device l from figures 13 to 16 is as follows.

In an atmospheric environment, a condition is obtained as shown in figure 13.

When the spray can 2 is activated by putting it under pressure via external ways, the wall portion 49 is pushed inward, as a result of which coupling parts 54 are pushed over the coupling part 55 and a condition results as shown in figure 14.

As a result of the permeation of gas into receptacle l_l, and eventually into chamber 15, a minor shifting of the valve body 22 may occur, for example, up to the position which is represented in figure 15.

When, during usage of the spray can 2, the pressure in the container 3 is diminished to a well-defined value which, in a practical embodiment, is chosen such that it equals approximately 3 bar, the closing portion 51 obtains a position whereby liquid from receptacle ll comes into chamber 15 and gas is produced, as a result of which the wall portion 49 bulges outwardly again and the products 8 and 9 come together freely again. As a result of this, a large quantity of gas is produced which, then, is sufficient to diffuse the total quantity of product 4. Hereby, valve 50 takes a position as represented in figure 16.

In figures 17 and 18, a variant is shown whereby the passage 12 is provided with a closure 57 which can be pushed away by means of a movable element 56. This closure 57 consists of a closing plate 58 which is clamped in a seat 59.

The movable element 56 consists of a valve stem with an extremity 60 with which the passage 12 can be closed off.

The lower extremity 61 of the valve stem cooperates with a pop-over system 62 with a bent wall portion 63 which can, surpassing a dead point, be popped over towards the inside, respectively outside.

The valve stem is positioned centrally by means of a recess 64 in the extremity 61 which cooperates with a deformation 65 in the wall portion 63, as well as by means of an elastically bendable flange 66 which is present around the valve stem and reaches up to the circumference of chamber 15. This elastic flange 66 simultaneously exerts a reversing force upon the valve ste when this latter is pushed into the direction of passage 12.

In an atmospheric environment, the device is in a condition as represented in figure 17.

When the device 1 is situated in a spray can 2 and, via external way, a pressure is built up in this spray can, the wall portion 63 pops over into a position as represented in figure 18. As a result of this, the valve stem, against the force of the flange 66, is pushed upward and the closing plate 58 is pushed out of seat 59. The closure of the passage 12, however, remains guaranteed because extremity 60 now closes off the passage 12.

When, as a result of dispensation of product 4, the excess pressure in the container 3 becomes lower than a well-defined value, for example, 3 bar, the wall portion 63 pops back into the position of figure 17 and, under the influence of the force exerted by flange 66, the valve stem will also return into the position of figure 17.

As a result of this, dissolvent, for example water, flows from the receptacle 11 through the passage 12 and through openings 67 which are provided in the flange 66. Thereby, this dissolvent comes into contact with the components of product 9, as a result of which these, as aforementioned, will react to a gas. They react until all of product 8 or 9 is used up. As a result of this, a pressure increase is created in chamber 15 and container 3, as a result of which a second load of pressure gas becomes available.

In figures 19 to 21, another variant is represented, whereby use is made of a movable element, more particularly a valve 68 with a hollow valve stem 69 with, on one hand, an inlet 70 which can cooperate with the wall 26, and an outlet 71 which ends up into chamber 15 and which can be closed off by means of a movable wall portion 63 which is executed analogous to wall portion 63 in the embodiment from figures 17 and 18.

In an atmospheric environment, this device 1 is in a condition as represented in figure 19.

When the spray can 2 is put under pressure, the wall portion 63 takes a position as represented in figure 20, as a result of which the valve stem 69 with the inlet 70 is pushed into receptacle 11. A passage of liquid, however, is not yet possible because outlet 71 still is sealed.

As soon as the pressure in the container 3 becomes lower than a well-defined value, the wall portion 63 pops back into the position of figure 19, as a result of which the liquid of receptacle 11 can flow, via the valve stem 69, into chamber 15, with the result that gas is created.

Instead of, as shown in the forms of embodiment of figures 13 to 21, making use of a movable element consisting of a pressure-reactive valve which provides for that the passage 12 is opened at a well-defined pressure decrease and subsequently remains open, according to a variant of the invention, it might also be possible to use a movable element which, by its movement, forms a passage not present up to then. Hereby, particularly a needle or similar is intended which makes a perforation between receptacle 11 and chamber 15.

In the devices represented in figures 9 to 21, for the first product 8, instead of a dissolvent, also a liquid acid can be used, whereas for the second product 9, then, instead of a dry mixture of an acid and a salt, use can be made exclusively of a salt.

According to a not represented variant, the complete device 1 can be put into a gas-tight extendable pouch before installation in container 3. In this manner, any contact between, on one hand, the product 4 and, on the other hand, the products 8 and 9 and the gas 10 can be excluded.

The compact design of the device 1, with only one quantity of product 8 and one quantity of product 9, offers the advantage that with a relatively small device 1, however, a large quantity of gas can be produced, compared to the known embodiments whereby the products are arranged in several compartments. By the fact that large quantities of gas can be generated in a simple manner, the invention is especially suited for applications whereby the gas 10 is not only used to exert a pressure upon the product 4, but also has to mix with the product 4 to be dispensed, for example for causing a foam formation in the case of a product to be foamed. In this case, the device 1 will contain such a quantity of products 8-9 to be reacted that the generated gas 10 can as well provide for the dispensation of the product 4 as for provision of the foaming effect.

The aforementioned device 1 can as well be arranged loosely in container 3 as mounted fixedly herein. According to the invention, the device 1 is not only intended for the application in classic spray cans but can be applied in all kinds of dispensing containers whereby the product to be dosed is expelled under pressure. The present invention is in no way limited to the forms of embodiment described by way of example and represented in the figures, but the aforementioned method and device can be realized according to different variants without leaving the scope of the invention.

Claims

Claims ,

1.- Method for generating pressure in a spray can and the like, whereby at least two products (8-9) are brought into contact with each other such, that, by doing so, a gas is produced and, thereby, a gas pressure is created, characterized in that the products (8-9) are brought together via a passage (12) , whereby the flow rate via this passage (12) is controlled by means of a movable element (18-50-56-68) which, in its turn, is controlled by the gas pressure prevailing around the device.

2.- Method according to claim 1, characterized in that the aforementioned products (8-9) are brought together progressively, whereby the gas production happens precisely in function of the quantity of gas which is necessary to restore after each activation of the spray can (2) the normal discharge pressure.

3.- Method according to claim 2, characterized in that the flow rate of the passage (12) is regulated by means of a pressure-reactive regulator (13), more particularly a pressure-reactive valve (18) reacting progressively to the pressure in the spray can (2), such, that the passage

(12) is closed every time the pressure in the spray can

(12) has reached a well-defined value, but is reopened every time the pressure again becomes lower than the aforementioned value.

4.- Method according to claim 1, characterized in that the passage (12) is closed off initially and, by means of the movable element (50-56-68), a remaining passage is created once, as a result of which the respective products (8-9) react completely, whereby this movable element (50-56-68) provides for opening the passage (12) when the pressure in the spray can (2) is diminished to a well-defined value.

5.- Device for the realization of the method of claim 1, characterized in that it at least consists of a receptacle (11) in which a first of aforementioned two products is available; a closable or closed passage (1₂) via which the first product (8) and the second product (9), by opening the aforementioned passage (12) or by means of realization of an open passage (12), can be brought into contact with each other; and a movable element (18-50-56-68) which can be commanded by means of the pressure surrounding the device (1) and which performs the opening, and eventually closing, of the passage (12), respectively the creation of such a passage (12).

6.- Device according to claim 5, characterized in that the movable element consists of a valve (18) which is part of a pressure-reactive flow regulator (13) and which provides in that the products (8-9) are brought together progressively according to the necessity to produce gas in order to keep the pressure constant.

7.- Device according to claim 6, characterized in that the flow regulator (13) is provided with a pressure- reactive element (17) controlling the valve (18), which consists of a housing (19) with at least one wall in the shape of a diaphragm (20-32-33) which moves under the influence of pressure alterations in the spray can (2) and which, in its turn, provides for the movement of the valve (18).

8.- Device according to claim 7, characterized in that the housing (19) is gas-tight and that an elastic element

(21) is enclosed herein which exerts a pressure force onto the diaphragm (20), such as a piece of rubber or plastic tube which, in compressed condition, is enclosed in the housing (19).

9.- Device according to any of claims 6 to 8, character¬ ized in that it is equipped with a pressure-reactive element (17) and a valve (18) which are designed such that the passage (12) is closed as soon as the pressure reaches a value which is higher than or equal to the dispensing pressure of the spray can (2) for which the device is intended, and is closed at least also at a pressure which is lower than or equal to atmospheric pressure.

10.- Device according to claim 5, characterized in that the movable element consists of a pressure-reactive element (56) or valve (50-68) which, at a well-defined decrease of pressure in the spray can (2), places itself into an open position and subsequently stays open, whereby a pressure increase is provided for once.

11.- Device according to claim 10, characterized in that it is provided with a motion system (48), respectively a pop-over system (62), which, at an initial increase of pressure, switches from a first position to a second position and subsequently, as a result of a well-defined pressure decrease, switches back, respectively pops back, and thereby places the valve (18) into an open position, whereby this motion system (48), respectively pop-over system (62), principally consists of a movable wall portion (49-63) of a chamber (15) wherein the second product (9) is situated.

12.- Device according to claim 11, characterized in that the motion system (48), by means of coupling means (53), cooperates with the valve (50), whereby these coupling means (53) during the first movement automatically perform a coupling between the motion system (48) and the valve (50), such that the valve (50) is drawn out of the passage (12) when the motion system (48) shifts back.

13.- Device according to claim 11, characterized in that the passage (12) is provided with a closure (57) which can be pushed away by means of the movable element (56); that the movable element (56) in a first position leaves a free passage (12j and in a second position closes this passage (12); and that the movable element (56) is connected to the pop-over system (62) in such a manner that this movable element (56) during the initial increase of the pressure is placed in the passage (12) and pushes away the closure (57), all of it such that, with a well-defined pressure decrease, this movable element (56), by the popping back of the pop-over system (48), is drawn out of the passage (12).

14.- Device according to claim 11, characterized in that the pop-over system (62) cooperates with a hollow valve stem with, on one hand, an inlet (70) which, by shifting of the valve stem, is either closed off or connected to the aforementioned receptacle (11), and, on the other hand, an outlet (71) which can be closed off by means of a wall portion (63) which is part of the pop-over system (62), whereby this pop-over system (62) provides for that, in initial condition, the inlet (70) as well as the outlet (71) are closed off, that the valve stem during the initial increase of the pressure is shifted by means of the popping over of the pop-over system and the inlet (70) is opened and that, during popping back of the pop- over system (62), the valve stem remains in the same position and the outlet (71) is opened.

15.- Device according to claim 5, characterized in that the movable element consists of a pressure-reactive element which, by its shifting, realizes a passage through which the aforementioned two products (8-9) can come together, such as, for example, a needle or similar which makes a perforation in a partition wall.

16.- Device according to any of claims 5 to 15, characte¬ rized in that it comprises means allowing to create an excess pressure in the aforementioned receptacle (11) of the first product (8), such that this product (8), when the aforementioned passage (12) is opened, is pushed out of the aforementioned receptacle (11), whereby these means consist of pressure passage means allowing for a pressure to be build up in the receptacle (11) by means of the pressure which prevails outside the receptacle (ID-

17.- Device according to claim 16, characterized in that the pressure passage means are formed by a wall (25) of the receptacle (11) which is manufactured of a material allowing a slow gas permeation under application of a pressure difference.

18.- Device according to any of claims 5 to 17, charac- terized in that the second product (9) is situated in a chamber (15) which connects to the aforementioned passage (12) and which is provided with one or more outlet openings (16) which are possibly provided with a return valve (30) .

19.- Device according to any of claims 5 to 18, charac¬ terized in that the first product (8) and the second product (9) are products which themselves react with each other to a gas.

20 Device according to any of the claims 5 to 1₈, characterized in that the first product (8) consists of a dissolvent and that the second product (9) consists of undissolved components which can react with each other to a gas when the aforementioned dissolvent is added hereto.

21. Device according to any of claims 5 to 20, character¬ ized in that products (8-9), respectively components, are applied which comply to one or more of the following items: - products (8-9) or components forming carbon dioxide when brought together;

- a first product (8) consisting of an acid in liquid condition, or an acid diluted in a liquid and a second product (9) consisting of a salt; - a first product (8) or component consisting of citric acid;

- a second product (9) or component consisting of calcium carbonate, barium carbonate or sodium bicar¬ bonate; - a second product (9) consisting of a compressed salt block;

- a first product (8) consisting of a dissolvent, such as water, and a second product (9) consisting of a dry composition of a salt and an acid, preferably in the shape of a compressed block.

22.- Device for generating pressure in a spray can, whereby at least two products (8-9) are brought into contact with each other such, that, by doing so, a gas is produced and, thereby, a gas pressure is created, characterized in that the first product (8) consists of a dissolvent and the second product (9) consists of a dry composition of a salt and an acid, preferably in the shape of a block of compressed powder.

23.- Spray can equipped with a device according to any of the claims 5 to 21, characterized in that the product (4) to be dispensed which is present in the spray can (2) is a product to be foamed and that the aforementioned device (1) contains εuch a quantity of products (8-9) to be reacted that the generated gas can provide for the expulsion of the product (4) as well as for the provision of the foaming effect.

Method and device for generating pressure in a spray can and the like, and spray can equipped with such device.

Figure 1.