EP0109361A1 - Actuating regulator - Google Patents

Abstract

In order to maintain constant the flow of a medium (18), expelled from a container using a compressed gas, notwithstanding the pressure drop in the container, a device, comprising a differential piston (2), having bearings with different diameters (12, 13, 14) and pressing on a spring (3) slides in a discharge channel (8a) having bearings with different diameters (8, 9, 10, 11) enlarged in proportion to the pressure drop of the container the passage sections between the piston (2) and the inner wall of the evacuation channel (8a) and causes, thanks to a change in direction of the flow of the medium (18), turbulence of a force such that they constitute a braking of the high flow when the pressure of the container is high and a braking of the flow which weakens as this pressure drops.

Description

The subject of the present invention is a thrust regulator of the kind defined in the preamble of claim 1. This thrust resulting from the pressure which acts on the surface of a medium inside a receptacle, for example an aerosol can , in order to maintain at least approximately constant the flow rate of this medium per unit of time during the expulsion of the latter out of the container and this non-obstant a pressure drop, proportional to the volume of this expelled medium, when the source of pressure consists of a compressed gas, for example air or nitrogen.

Many countries prohibit the use of chlorofluorinated hydrocarbons of the FREON type as propellant aerosols to contribute to the protection of the ozone belt which protects our globe against excessive ultraviolet radiation.

Since then, propane-butane mixtures or dimethyl ether have been used more and more as propellants.

If FREON is dangerous for the environment, propane-butane and dimethyl ether constitute a danger by their explosive nature.

We tried to use CO ₂ , N ₂₀ N ₂ 0 or simply compressed air as propellant. However, this use comes up against the fact that as the expulsion of the product from a container this results, by enlarging the remaining volume of the container, a pressure drop, proportional to this enlargement and consequently a reduction in the flow rate per unit of time and, if the product is sprayed , there is at the same time an increase in the size of the droplets and the spray becomes too wet, therefore unacceptable. In addition, the use of CO ₂ and NZO should be avoided, because these gases are partially absorbed by the product to be sprayed and which are therefore expelled with it, which causes the valve to flow after closing. residual in the form of drops. These problems can partially be solved by the use of the nozzle that the author of the present invention describes in US Patent No. 4,260,110 and which allows fine spraying of products with a low purely mechanical pressure, therefore without any known propellant gas. which, by its expanding force in contact with atmospheric pressure, makes the droplets explode when they come out of the nozzle. In this nozzle it is only the "mechanical break-up" which ensures, even with pressures below 2 bar, good spraying.

However, by using this nozzle with aerosol cans using compressed gases as propellants, there is a high flow rate per unit of time with fine spraying when the box, filled to the maximum is under high pressure and a low flow rate per unit of time with a always fine spray when the pressure has decreased following the evacuation of product.

In order to solve this problem of variable flow rates as a function of a pressure drop in the box, the author of the present invention proposes in European patent application No. 81902294.8 "Schubregler zur Verwendung im Innern von unter Gasdruck stehenden Behâltern", a regulator thrust, by means of which the flow of a medium per unit of time is kept at least approximately constant, expelled from a pressurized container not preventing the pressure drop, acting inside the container on this medium . In an evacuation channel there is a differential piston, the dimension of which relative to that of the evacuation channel is such that a minimum passage section remains for the evacuation of the medium at any time of expulsion. The differential piston has surfaces of different dimensions at the ends, the largest surface being opposite to the flow of the medium. The differential piston is supported on a spring which is calibrated so that under the action of the pressure of the container of a predetermined value, it is compressed so that the differential piston takes a first end position, by which it reduces the passage section of the evacuation channel to a minimum section and that in proportion to the pressure drop, following the evacuation of medium from the container, the spring expands and displaces the piston so that this results in a progressive enlargement of the passage section of the evacuation channel until the piston reaches a second end of travel, as soon as a minimum pressure, predetermined, settles in the container. The shape of the piston relative to that of the evacuation channel is chosen so that by its displacement it ensures that the sum resulting from the multiplication of the pressure of the container by the remaining passage section, remains, at least approximately, constant.

Each of the embodiments proposed in this European application has shortcomings and disadvantages, such as too high permeability of the membranes at vapor pressure, too high price of parts injected in synthetic materials due to the pressure required, regulation and consequently jerky spraying. due to an axial back and forth movement of the differential piston.

The object of the present invention is to provide a regulator which makes it possible, together with the nozzle as described in the aforementioned American patent, to obtain a constant flow rate per unit of time non-obstant the pressure drop in an aerosol container having as propellant a compressed gas such as nitrogen and air settling in as the box is emptied of its contents.

According to the invention, this object is attained by a regulator as defined in claim 1.

• fig. 1 une vue en coupe d'une première forme d'exécution du régulateur, réglant le débit sans avoir recours à des turbulances placé sur la valve ouverte d'une boîte aérosol dans un poussoir muni d'un gicleur,
• fig. 2 une vue en coupe d'une deuxième forme d'exécution du régulateur, réglant le débit à l'aide de turbulances, placé sur la valve fermée d'une boîte aérosol dans un poussoir muni d'un gicleur,
• fig. 3 le régulateur de la fig. 2 dans le cas de la valve ouverte,
• fig. 4 une vue en perspective partiellement en coupe sur un détail du régulateur et du gicleur selon la fig. 2,
• fig. 5 le piston tel qu'il est utilisé dans les formes d'exécution du régulateur selon les figs. l et 2,
• fig. 6 une vue éclatée en perspective d'une troisième forme d'exécution du régulateur logé dans un cylindre de montage avec le gicleur,
• fig. 7 un diagramme qui montre l'effet de régulation du débit par unité de temps obtenu par l'utilisation du régulateur selon l'invention en commun avec le gicleur selon le brevet américain no 4.260.110, comparé aux débits obtenus sans régulateur.

The details of the present invention appear from the description which follows, relating to preferred examples of execution, but without limitation, illustrated in the appended drawing which shows in:

• fig. 1 is a sectional view of a first embodiment of the regulator, regulating the flow rate without using turbulances placed on the open valve of an aerosol can in a pusher provided with a nozzle,
• fig. 2 is a sectional view of a second embodiment of the regulator, regulating the flow rate using turbulances, placed on the closed valve of an aerosol can in a pusher provided with a nozzle,
• fig. 3 the regulator of fig. 2 in the case of the open valve,
• fig. 4 a perspective view partially in section on a detail of the regulator and the nozzle according to FIG. 2,
• fig. 5 the piston as used in the embodiments of the regulator according to FIGS. l and 2,
• fig. 6 is an exploded perspective view of a third embodiment of the regulator housed in a mounting cylinder with the nozzle,
• fig. 7 a diagram which shows the effect of regulating the flow rate per time unit obtained by the use of the regulator according to the invention in common with the nozzle according to American patent No. 4,260,110, compared to the flow rates obtained without regulator.

In fig. 1, the pusher 6 is provided with a cage 1 which has a breakthrough with a large diameter 39, a diameter 40 and a small diameter 50 which leads to a channel 60 to supply a nozzle 5. In the cage 1 is a piston differential 2 whose upstream side has a large diameter 14 with the chamber 17 which serves as a fulcrum for the column of the medium 18, while its downstream side has a small diameter 12 and one end 12a having an aerodynamic form of reduction of turbulence. Between the upstream edge 61 of the channel 60 and the end 12a of the piston 2 is a distance "A". This distance "A" must be large enough so that the turbulence which is created around the end 12a, despite its aerodynamic shape, when the latter is too close to the channel 60, can agglomerate, in order to constitute a flow laminar before reaching the upstream edge 61 of the channel 60. In addition, the small diameter 50 of the cage 1 has, opposite the entrance to the channel 60, a curved wall 41, intended to eliminate the formation of other turbulences by angles, on the contrary, to facilitate the flow of the laminar flow towards the nozzle 5. The piston 2 is provided with the bearing surface 15 of the spring 3 and the grooves 16 and 16a through which the medium 18 can flow, even if the spring 3 is compressed to block and forming a sealed wall. The bearing surface 15 also serves as a stop for limiting the stroke of the piston 2, when the latter is moved downstream by the medium 18 under the highest expulsion pressure. As the expulsion pressure drops, the spring 3 expands and pushes the piston 2 upstream where its stroke is limited by the clamping sleeve 20 which adapts to the piston 3 $ of a valve aerosol not shown located inside the ferrule 31. On its periphery the ferrule 31 carries the chimney 53 which serves as axial guide to the pusher 6 to avoid a too pronounced tilting, tilting which is inevitable due to the length of the pusher , whose only point of support is the piston 35 which, not being for technical reasons not too guided, promotes an undesirable tilting. One could also limit a tilting using a skirt, integral with the socket 20 and which covers the ferrule 31.

When the pusher 6 is actuated and therefore the medium 18 is expelled by the strongest pressure, that of the filling, the piston 2 is moved in the downstream direction - not only by the thrust of the medium 18, but also by to a suction, created at the entrance of the channel 60 by the expansion of the medium under pressure, but also thanks to a swirl printed on the medium 18 and therefore the spring 3 is calibrated only according to the thrust of medium 18 and not not additionally as a function of this suction force, it is too weak at the start of regulation to overcome these two added forces and the piston 2 remains stationary, instead of moving in the upstream direction. As soon as by a certain evacuation of the medium 18 the expulsion pressure drops, the spring suddenly pushes the piston 2 into the regulating position, then corresponding to the residual pressure. It is therefore necessary, in order to obtain from the start a continuous displacement of the piston 2, use a differential spring which on a first rebound travel provides more force than on the rest of the travel.

Fig. 2 shows the second embodiment of the device according to the invention housed in a pusher 6 which serves as an opening element of the valve 25, which consists of the body 26, the seat 27, the inner seal 28, the seal outside 29, spring 30 and ferrule 31. A dip tube is not shown. The pusher 6 has the rod 32, provided with the line 33, parallel to the axis of the rod 32 and the line 34, perpendicular to the line 33. The rod 32 is inserted in the seat 26 of the valve 25 so that the seat 26 closes off the inlet of the pipe 33. The pipe 34 is placed so that its inlet is inserted in the upper part of the joint 28. This arrangement of the pipes 33 and 34 is imposed by the fact that no experienced commercial aerosol valve is waterproof immediately after closing the valve after use. When the propellant is a soluble gas such as FREON etc. there is an almost instantaneous evaporation and the flow of medium after closing the valve 25 is not noticed. But when compressed gas such as air or nitrogen is used as propellant, as recommended for the device according to the invention, the expelled medium contains no factor which, by its force of expansion in contact with the atmospheric pressure would instantly evaporate the medium which still flows from the valve after it has closed and there is a flow of medium at nozzle 5 which can last up to twenty seconds after the valve has closed. This flow is eliminated by the arrangement of the pipes 33 and 34 of the pusher 6. Not that the valve 25 has simply become sealed, the inlet of the pipe 34 being placed in the seal 28 which therefore closes it, does not allow more in the medium, still flowing in the seat 26, to penetrate into the pipe 34, the pipe 33 being, as already described, closed by the seal 28.

This design is essential especially for the use of the object of the invention to spray media, an excessive amount of which leaves the nozzle, as it dries, could obstruct it.

Fig. 2 shows the second variant of the object of the invention at rest, the spring 3 having pushed the piston 2 into its starting position, while FIG. 3 illustrates the position of the piston 2 during use, when the valve not shown is open and the medium 18 and expelled with the highest pressure from the container, also not shown.

The regulation, explained using figs. 2, 3, and 4, takes place as follows: As soon as the valve 25 opens, the medium 18 penetrates on the one hand into the chamber 17 of the piston 2 and on the other hand flows along the length of the piston 2 in the discharge channel 8a. Under the pressure of the medium 18 the piston 2 is pushed in the direction of the nozzle 5 and compresses the spring 3. The front face of the piston 2 bears firmly against the center of the core 4 and is therefore placed in the chamber 23, of which it decrease the volume. The protrusions 22 of the core 4 and the edge 19 of the nozzle being in firm contact with the cylinder 1, the medium 18 under pressure can only move towards the nozzle 5 through the grooves-conduits 24. As they are perpendicular to the channel 8a of the cylinder 1 there is caused at the outlet from the grooves 24 turbulence, the change in direction of the flow in a perpendicular manner being at the base of the obstructing turbulence observed. Because the grooves 24 are tangential with respect to the chamber 23, the flow of the medium 18, although turbulent, is subjected to a direction of rotary flow, perpetuated by the ciruclar edge 19 which transforms the turbulent flow into laminar flow which finally feeds the nozzle 5 through the channels 21. Because the turbulence is transformed in laminar flow, they only constitute a braking force which is all the stronger as the pressure of the medium is high, but without being able to reach a force for blocking the flow.

The braking, imparted to the flow of the medium 18 by the turbulence, is, in this embodiment of the regulator, a part of the regulation of the flow per unit of time, the spring 3 not intervening immediately but only, when the thrust of the medium 18 decreases to the point that the spring 3 can relax and open the passage section at all levels of the bearings of the piston 2.

Practical tests have shown that when the valve 25 opens, the product 18, leaving the nozzle 5, is not yet sprayed, but is expelled in the form of a few large drops. This is explained by the fact that the medium 18 has not yet been expelled with the entire pressure available, because the valve 25 does not open instantly.

To eliminate this phenomenon, the rod 32 of the pusher 6 has a large diameter 32a, with which it rests on the seal 28, the pipe 34 being located immediately below the diameter 32a. Line 34 does not have a round section, but rectangular. Therefore, when the pusher 6 is moved downward to open the valve 25, it remains closed for longer by the seal 28 than a round pipe which, for a section of identical size, must have a diameter such that '' part of the inlet is already disengaged from the seal 28, without the valve 25 being sufficiently open to release all the pressure, under which the medium 18 is located, while a rectangular pipe 34, of a predetermined height , requires on the one hand a larger path for movement of the pusher 6 so that its entry is clear of the joint 28 and on the other hand, instead of presenting as a inlet a small part of its section, as is the case for a round pipe, according to this predetermined height, the pipe 34 presents its entire inlet section at medium 18 which, thanks to the optimum opening of the valve 25, due to the larger path made by the pusher 6 to clear the entry of the rectangular pipe 34, is expelled with all the pressure available.

The regulator according to the invention as shown in detail in FIG. 4 is constituted by the cage 1, the differential piston 2, the compression spring 3 and the core 4 which can be made in one piece with the nozzle 5, housed either in a pusher 6 or in a mounting cylinder 7, illustrated in fig. 6. The cage 1 has the conduits 8, 9, 10 and 11, These conduits together forming the evacuation channel ₁ n 8a. The piston 2 is divided into three parts, each of which has a separate regulation bearing, namely the small diameter 12, the average diameter 13 and the large diameter 14. In addition, it is provided with the bearing surface 15, seat of the spring 3. In order to allow the medium 18 to pass through the various conduits of the cage 1 when the spring 3 is completely compressed, the piston 2 is provided with grooves 16 and 16a. At the large diameter 14, the piston 2 has the chamber 17 which serves as a fulcrum for the medium 18, which ensures effective displacement of the piston 2 under the action of pressure, under which the medium 18 is located. The force of the spring 3 is chosen so that the initial pressure of 5 bar of a medium 18 is fully compressed to allow the piston 2 to press firmly against the core 4 which therefore serves as a limit switch piston 2. The core 4 is inserted into the nozzle 5 so that it forms with the edge 19 thereof a depression 19a, from which the channels supply 21 of the nozzle 5. The upstream face of the core 4 carries the protrusions 22, the center of which presents the chamber 23, from which multiple grooves 24 emerge, each of which forms a tangent with the circumference of the chamber 23. The face upstream of the protuberances 22 and the edge 19 of the nozzle 5 are in firm contact with the cage 1 so that the grooves 24 become conduits which connect the chamber 23 to the recess 19a which thus becomes an annular conduit from which the medium 18 is introduced into the channels 21 of the nozzle 5.

The regulation of the flow using the regulator according to the invention is illustrated in FIG. 7. Line 45 represents the flow per unit of time, when using a commercially available nozzle, line 36 shows the flow per unit of time, obtained when using the nozzle according to US Pat. No. 4,260,110 The author of the present invention and line 37 illustrates the flow rate per unit of time obtained by using the regulator according to the invention with the aforementioned nozzle.

Claims (28)

1. Thrust regulator, composed of a differential piston (2) which rests on a compression spring (3), housed inside a discharge channel (8a) of a medium (18) which is under pressure inside a container, characterized in that the differential piston (2) has such a dimension with respect to that of the discharge channel (8a) that a minimum passage section remains for the evacuation of the medium (18) at all times of expulsion, that the differential piston (2) has at the ends (12; 14) surfaces of different dimensions, that the largest surface (14) is opposite to the flow of the medium (18) that the spring (3) is calibrated so that under the action of the pressure of the container of a predetermined value it is compressed so that the differential piston (2) takes a first end position, by which it reduces the passage section of the discharge channel (8a) to a minimum section and that in proportion to the pressure drop, following the e emptying of medium (18) from the container, the spring (3) relaxes and displaces the piston (2) so that this results in a progressive enlargement of the passage section of the evacuation channel (8a) until the piston (2) reaches a second end-of-travel position as soon as a predetermined minimum pressure is installed in the container, when the shape of the piston (2) relative to that of the evacuation channel (8a) is chosen to so that by its movement it ensures that the sum resulting from the multiplication of the pressure of the container by the remaining passage section remains at least approximately constant, that the discharge channel (8a) opens into a chamber (23) from which start from the channels (24) which each form a tangent with the circumference of the chamber (23) and which open into a circular channel (19a) from which the supply channels (21) of the nozzle (5) start, that the tangential channels (24) of the chamber (23) are perpendicular to the discharge channel (8a) and to the supply channels (21 ) of the nozzle (5), that the front face of the downstream end (12) of the piston (2) bears, under the effect of the highest pressure of the container, firmly against the upstream face of the core (4 ) that the passage sections between the piston (2) and the inner wall of the discharge channel (8a) decrease continuously in the downstream direction, that a spring (3) is provided, the force of which is chosen so that a predetermined pressure, acting on a medium surface (18) compresses it so that it allows the differential piston (2) to press firmly against the upstream face of the core (4). 2. Regulator according to claim 1, characterized in that the assembly is placed outside a container, but inside a diffusion element (6, 7) of a valve (25). 3. Regulator according to claims 1 and 2, characterized in that the entire device is located upstream and in the axis of the nozzle (5). 4. A regulator according to claim 1, having a pusher, the rod of which, being inserted into a valve, has a vertical pipe, into which a horizontal pipe blows, characterized in that the pusher (6) has a rod ( 32), having on a part a diameter (32a) of such a dimension and a length such that it rests on the seal (28) of the valve (25), only in the vertical pipe (33 ) ends a horizontal pipe (34) which has a rectangular section and that the upper wall of the horizontal pipe (34) is supported on the upstream end of the large diameter (32a) of the rod (32). 5. Regulator according to claim 1, characterized in that the largest section of the small diameter (12) of the piston (2) represents at least 94% of that of the smallest pipe (8) of the discharge channel (8a). 6. Regulator according to claim 1, characterized in that the largest section of the mean diameter (13) of the piston (2) represents at least 95% of that of the mid-pipe (9) of the discharge channel (8a). 7. Regulator according to claim 1, characterized in that the largest section of the large diameter (14) of the piston (2) represents at least 97% of that of the medium pipe (10) of the discharge channel (8a ). 8. Regulator according to claim 1, characterized in that the largest section of the large diameter (14) of the piston (2) represents at least 90% of that of the large pipe (11) of the discharge channel (8a ). 9. Regulator according to claim 1, characterized in that the length of the large diameter (14) of the piston (2) is at least identical to that of the large pipe 11 of the discharge channel (8a). LO. Regulator according to Claim 1, characterized in that the length of the large diameter (14) of the piston (2) is at least 25% greater than that of the large pipe (11). 11. Regulator according to claim 1, characterized in that the volume of the piston (2) which is inserted in the chamber (23) of the core (4) represents at most 16% of that of the chamber (23). 12. Regulator according to claim 1, characterized in that the section of the circular channel (19a) represents 50% of the total of the sections of the tangential channels (24). 13. Regulator according to claim 1, characterized in that between the downstream face of the mean diameter (12) of the piston (2) and the inlet of the pipe (8) of the discharge channel (8a) is maintained a annular space when the piston (2) presses against the core (4) of the nozzle (5), space whose volume represents 0.05% of the volume of the mid-pipe (9) minus the volume of the average diameter ( 13) of the piston (2), housed in this pipe (9). 14. Regulator according to claim 1, characterized in that the entire device with a nozzle (5) are housed inside a mounting cylinder, the upstream face of which is provided with a breakthrough diameter smaller than the large diameter (14) of the piston (2). 15. Regulator according to claim 1, characterized in that the cage ( ₁ ) has three different diameters, a large diameter (39) upstream, an average diameter (40) in the middle and a small diameter (50) downstream , that the upstream side of the piston (2) has a diameter (14) larger than its downstream side (12), that the distance (A) between the downstream end (12) of the piston (2) and the upstream edge ( 61) of the nozzle supply channel (60) (5) is at least 150% larger than the small diameter (50) of the cage (1), than the downstream end (12) of the piston (2) has an aerodynamic form for reducing turbulence and that the spring (3) is at least as long as the part of the cage (1) having the mean diameter (40). 16. Regulator according to claim 15, characterized in that the bearing surface (15) of the spring (3) serves as a stop for limiting the stroke of the piston (3) when the latter is pushed in the downstream direction by the highest pressure which acts on the medium (18). 17. Regulator according to claim 15, characterized in that the length of the spring (3) is greater than that of the part of the cage (1) having the average diameter (40). 18. Regulator according to claim 15, characterized in that the upstream face of the piston (2) has a chamber (17). 19. Regulator according to claim 15, characterized in that the length of the part of the cage (1) having the largest diameter (39) is the same as the length traversed by the piston (2) under the effect of the highest pressure acting on the medium (18). 20. Regulator according to claim 15, characterized in that the wall (41) of the channel (60) which is located opposite the inlet of the supply channel (8a) of the nozzle (5) has a curvature. 21. Regulator according to claim 1, characterized in that the spring (3) is a difforential spring. 22. Regulator according to claim 1, characterized in that the downstream face of the surface (15) of the piston (2) on which the spring (3) is supported is provided with multiple grooves (16; 16a) which extend parallel to the axis of the piston (2) along its part (15), surrounded by the spring (3). 23. Regulator according to claim 1, characterized in that apart from the spring (3) it is made of molded plastic. 24. Regulator according to claim 1, characterized in that the geometry of the piston (2) remains identical for all the pressures used inside a container and that only the force of the spring (3) changes. 25. Regulator according to claim 1, characterized in that the strongest spring (3) is compressed over a predetermined distance by a pressure of maximum 10.83 bar at an ambient temperature of 20 ° C. 26. Regulator according to claim 1, characterized in that the passage section between the downstream pipe (8) and the small diameter (12) of the piston (3) is from 2.0 to 0.12 mm ² for adjustment the flow rate of products with a viscosity greater than 10 centipoise and 0.12 to 0.06 mm ² for adjusting the flow rate of products with a viscosity of less than 10 centipoise when the piston (2) is fully housed in the pipe swallows (8). 27. Regulator according to claim 1, characterized in that the large diameter (14) of the piston (3) is pushed by the force of the spring (3) towards the valve (25) when the latter is closed. 28. Regulator according to claim 1, characterized in that it is housed inside a pusher (6) of a valve (25) when the device is used with an aerosol can or an aerosol can.

Images