GB2049827A

GB2049827A - Improvements in or Relating to Valves for Aerosols

Info

Publication number: GB2049827A
Application number: GB8010112A
Authority: GB
Original assignee: Perfect Valois Ventil GmbH; Perfect Ventil GmbH
Current assignee: Aptar Dortmund GmbH
Priority date: 1979-03-27
Filing date: 1980-03-26
Publication date: 1980-12-31
Also published as: FR2452442B1; DE2912081A1; FR2452442A1

Abstract

A valve housing 1 is held in a cover 2 by peripherally distributed inwardly directed indentations 4 engaging beneath beads 5 on the valve housing, the latter having an annular clamping rim, 6 a gasket 7 being clamped between the rim and the end wall 8 and having an edge portion projecting beyond the clamping zone. Filling aperture 25 are formed between beads 5. Flats 26 are formed beneath the beads 5 and the housing is thickened at 28 inwardly of the apertures 25. <IMAGE>

Description

SPECIFICATION Improvements in or Relating to Valves for Aerosols The present invention relates to a valve for aerosols.

In the valve described in DE-OS 2,503,626 and DE-AS 2,559,444, the bead completely surrounding the valve housing is extended in the radially outward direction and towards the end wall of the valve holder to abut the same, the extension being in the form of a support wall formed with axially parallel incisions. The indentations engage beneath the support wall.

When the aerosol is filled with a pressure medium at relatively high pressure, the pressure medium is introduced not only via the valve stem, the valve housing interior and a duct in the valve housing spigot for an immersion tube, but also outside the valve stem via the filling aperture, which is formed between the valve stem and the inner edge of a circular aperture in the end wall of the valve holder. During the filling operation, the pressure medium so acts on the gasket for sealing off the outlet duct that the two edge zones thereof projecting outwardly and inwardly, respectively, in the radial direction beyond the annular clamping rim are folded over against the adjoining walls of the valve housing towards the interior of the aerosol.In this way, the pressure medium is introduced via the filling aperture past the valve stem through the duct and the immersion tube, on the one hand, and through the axially parallel incisions of the support wall outside the valve housing, between the latter and the peripheral wall, on the other hand. In this way, rapid filling is possible even if the immersion tube has a relatively small cross-section. Although the pressure medium can enter relatively unobstructedly during the filling operation with the described valve, the diameter of the valve body, and hence of the peripheral wall of the valve holder, is relatively large so that there are production problems.Since the relatively large radial distance between the abutment surfaces for the indentations in the valve housing increases the size of the lever arm for the forces operative during filling, the valve housing may be torn out of the anchoring in the indentations.

It is an object of the present invention to provide a valve so that reliable filling is possible, even at high pressure, using a valve housing of relatively small radial dimensions.

According to the present invention there is provided a valve for an aerosol, which valve comprises a valve holder having an end wall and a peripheral wall, a valve housing immovable relatively thereto, peripherally distributed inwardly directed indentations in the peripheral wall engaging beneath a bead on the valve housing, the latter having an annular clamping rim, and a gasket for sealing off an outlet duct, the gasket being clamped between the rim and the end wall, having an edge portion projecting beyond the clamping zone and having a peripheral edge, a filling aperture being provided only inside the clamping rim having the end wall and the gasket being adapted to lift away from the end wall in response to filling pressure, to form a filling path, radially extending and substantially axially parallel intermediate spaces being provided to increase the cross-section of the filling path in the region of the bead, a plurality of projections being distributed symmetrically over the periphery of the valve housing, projecting radially from the outer wall, the intermediate spaces being provided between the projections, and the indentations engaging beneath the projections and between the intermediate spaces on the valve housing outer wall.

It is particularly preferred that the valve body has a polygonal inside section and the valve stem has a circular outside section inscribed in the polygon, the number of sides of the polygon being equal to the number of intermediate spaces, the polygon apices being situate at the centre of the thickened portions forming the bead projections.

A valve in accordance with the present invention is suitable not only for liquid propellants (such as fluorohydrocarbons and hydrocarbons), but also for gaseous propellants (such as CO2 and N2O), which are introduced into the aerosol under pressure via the valve. The pressure medium or propellant is largely introduced through the space between the peripheral wall of the valve holder and the outer wall of the valve housing, particularly between the intermediate spaces between the projections, and is only slightly introduced via the immersion tube. This is an advantage, particularly in the case of valves having a narrow capillary riser and when aerosols are filled with gaseous propellants.

During filling with gaseous pressure media or propellants, foaming of the active substance/solution already present in the aerosol is intended to create the largest possible surface to ensure rapid absorption of the gaseous propellant by the solution. Consequently, the building up of a very high pressure in the aerosol during filling should be avoided, since the aerosol might be damaged as a result. With the construction of the valve according to the present invention, the flow of gas supplied during filling can be injected very uniformly on to the surface of the solution in the aerosol, the solution also being rendered turbulent with a very deep effect. This is achieved by means of defined flow paths formed by the intermediate spaces between the projections and the indentations on the peripheral wall of the valve holder.The special construction of the valve housing has enabled the indentations to be specifically oriented, that is crimped with a specific orientation, while the stability of the valve housing with respect to deformation during filling is increased. The valve housing is prevented from being torn out of the indentations by the pressure during filling. It has surprisingly been found that, with the valve according to the invention, increasing pressure on filling with gaseous propellants results in less build-up of positive pressure and greatly reduces the risk of the aerosol bursting or exploding. An additional advantage is that the aerosol can be filled more rapidly with such a valve.

Since the valve housing of such valves is pressed downwards with respect to the top of the valve holder by the high pressure during filling, if the pressure medium flows above the valve housing clamping rim past the gasket which now no longer bears against the end wall, the valve housing must be sufficiently flexible and yet be sufficiently stable to prevent its being torn out of its fixing, that is the indentation or the crimp. The valve housing construction according to the present invention satisfies these requirements, particularly if it is made from a polyamide.

The valve constructed according to the present invention basically does not differ in size from conventional valves with a conventional valve housing without such filling facilities. Even in the case of aerosols previously provided with conventional valves, the pressure medium filling time can be reduced, and the saving in time is extraordinary in the case of aerosols having a capillary riser. As a result of this construction the valve according to the present invention can be applied to practically every case, that is not only to special cases such as capillary risers or gaseous pressure media, but even to standard cases in which the riser is fitted over a nipple or spigot. As a result of this versatility, only one kind of assembly machinery and filling equipment is required, while the stock of parts required for the valve is simplified.This results in considerable saving in costs, only very minor conversion being necessary on existing assembly machinery.

For a better understanding of the present invention and to show how the same may be put into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 shows a longitudinal sectional view on the line I-I of Figure 2 of an aerosol valve in accordance with the present invention, Figure 2 shows a cross-section through the valve housing on the line II--II of Figure 1, Figure 3 shows a longitudinal sectional view, on line Ill-Ill of Figure 1, of another embodiment of aerosol valve in accordance with the present invention, and Figure 4 shows a cross-sectional view through the valve housing on the line IV--IV of Figure 3.

Referring to Figures 1 and 2 of the accompanying drawings, a valve housing 1 is fixed in a valve holder 2, which forms the top of a lid closing an aerosol. To this end, the peripheral wall 3 of the valve holder 2 has inwardly extending indentations 4 at a number of places along the periphery, the indentations being made, for example by crimping and engaging beneath projections 5 on the valve housing 1. The top edge of housing 1 is formed with an annular clamping rim 6, which presses a gasket in the form of a washer 7 against the end wall 8 of the valve holder 2. The pressure for this purpose is provided by the indentations 4, which press the projections and hence the valve housing towards the end wall 8 and against the gasket 7.

The interior 9 of the valve housing contains a valve stem 1 0, one end of which projects out through a circular aperture 8a formed in the end wall 8 of the valve holder 2. The valve stem 10 has an axial inner passage 11 at this outwardly projecting end, the passage communicating at the bottom with an annular groove 1 3 on the outer periphery of the valve stem 10 via a transverse hole 12. The diameter of the bottom annular shoulder of the annular groove 13 is larger than the diameter of the circular aperture 8a. A compression spring 14 bears against top end faces 1 6 of radial inner ribs 1 5 in the interior 9 of the valve housing and a bottom annular shoulder 1 Oa of the valve stem 10.When the latter is in the closed position, the gasket 7 is, therefore, sealingly pressed against the bottom of the edge of the circular aperture 8a. The aerosol product subject to the pressure of a propellant gas cannot, therefore, escape. When the valve stem 10 is pressed down against the force of spring 14 into the open position, for example by means of a valve head 18, the transverse hole 12 is opened as shown in Figure 1. Consequently, the product under pressure can enter the interior 9 via an immersion tube (not shown) connected to a spigot 1 9 of the valve housing and via a duct 20 formed in the spigot 1 9. The product under pressure than emerges, via annular groove 13, the transverse hole 12 and the inner passage 11, into the valve head 18, and leaves via a spray nozzle 21 provided at the valve head 18.

Above the annular shoulder 13, the valve stem 10 has an annular bead 1 Ob with a conical transition 1 Oc which, when the valve stem 10 is in the closed position, fills the circular aperture 8a in the end wall 8 of the valve holder 2. When the stem 10 is in the open position, however, transition 1 Oc is below the edge of the circular aperture 8a and is then approximately level therewith so that an annular filling aperture 22 is formed. The liquid or gaseous pressure medium is introduced at very high pressure through this aperture 22 when the aerosol is charged. The valve head 18 may be withdrawn from the valve stem 10 for this purpose. As a result of the high pressure on filling, the part of the gasket 7 projecting inwardly from the rim 6 is pressed against the inner periphery of the interior 9 of the housing 1 so that the pressure medium can flow past the stem 10 through the passage 20 and the immersion tube and into the aereosol. At the same time, the gasket 7 is pressed on to the rim 6 and the part of the gasket 7 projecting radially outwards above the rim 6 is pressed against the outer periphery of the housing 1. This creates another flow path between the end wall 8 and the peripheral wall 3 and the outer periphery, that is the area of the bead, of the valve housing 1. There is practically no resistance to this flow path for the pressure medium as might occur, for example, on filling through the duct 20 in the case of capillary risers.Rapid filling of the aerosol with pressure medium can thus be carried out at very high pressure.

To ensure very rapid and reliable filling with valve housings whose volume is equivalent to that of conventional valve housings, the top end of the valve housing 1 is constructed in a special way according to the invention.

Projections 5 distributed symmetrically over the periphery project radially from the outer wall of the valve housing 1. At the top and bottom they have shoulders 23 and 24 which are substantially parallel to one another, the top shoulder allowing the gasket to be folded over while the bottom shoulder enables the same to be flexible by reducing the housing wall thickness.

Intermediate spaces 25 disposed substantially symmetrically with respect to the inner ribs 1 5 are provided between the shoulders.

Tangential surfaces 26 are provided beneath each of the projections 5, the indentations 4 being situate near the surfaces 26. The tangential surfaces 26 also enable an assembly machine to be fed with the housings in such a manner as to ensure orientation of the crimp. This orientation guarantees a constant and reproducible position of the valve housing 1 in the valve holder 2.

As shown in Figures 1 and 2, four projections 5, intermediate spaces 25, and tangential surfaces 26 are distributed symmetrically over the periphery of the valve housing. Alternatively, three or more than four projections, intermediate spaces and tangential surfaces may be provided.

To increase stability, the outer wall of the valve housing 1 has a thickening 27 in the region of the intermediate spaces 25, and a thickening 28 on the inner wall. The surfaces of the two thickenings 27 and 28 substantially parallel to the axis of the valve housing 1 form tangential planes or planes parallel to a tangent to the periphery of the valve housing 1 and symmetrical in each case to the associated intermediate space 25. The intermediate spaces 25 are each bounded by the adjacent projections 5, the end faces 29 of which are directed parallel to a major plane of the valve housing 1 passing through the centre of the intermediate space 25. The thickening 28 on the inner wall gradually leads into the rim 6. The thickening 27 on the outer wall merges step-wise into the outer wall of the valve housing 1 in the direction of the spigot 19. However, this transition may be gradual.

In the embodiment shown in Figures 3 and 4, a valve body 41 is housed in a lid 42. A peripheral part 43 of the latter comprises six deformations 44 formed below six projections 45 which form a circular bead interrupted by six intermediate spaces 25 which form vertical passages for the propellant fluid or gas. This embodiment also has an axial circular clamping rib 46 which urges a gasket 47 against the front wall 48 of the lid, to allow additional compression when the propellant is filled under pressure, the same then passing between the lid 42 and the valve body 41.

As in the first embodiment, the system comprises a valve stem 50 with a bore 51 and a communicating hole 52, which have the same functions. The stem 50 has an annular collar 50b with a conical or rounded transition zone 50c so that, in the depressed position, an annular opening 22 is released for filling while in the raised position, as illustrated, aperture 22 is narrow enough to prevent the gasket 47 from moving into the gap. The valve stem is different from that shown in Figures 1 and 2. Spring 1 4a is engaged in a bell-shaped cavity 54 in the valve shank 50a, instead of being disposed on a pin as shown in Figure 1.

The valve stem 50 is guided by the valve shank 50a-which forms a skirt surrounding the spring 1 4a-sliding in the hexagonal cavity 56 of the valve body. Passages 57 are thus left open to expel the active product during usage. The hexagonal shape of the inner section of the valve body thus provides an internal excess thickness 28 at each intermediate space.

During filling, passages are thus left open (see the left-hand side of Figure 3) between the peripheral wall of the lid and the valve body, although the latter is held by the deformations 44 (see the right-hand side of Figure 3) below the beam projections 45.

The outer wall of the valve body 41 is provided with ribs or thickened portions 59 which form a reinforcement and between which there are passages for filling the propellant, and which allow positioning in an installation machine. In this case the thickened portions 59 are level with the bead projections 45. Advantageously, the outer surface of these thickened portions may be flat, being formed by a plane parallel to the valve axis. As in the first embodiment, the end faces 29 of the bead projections 45 are in this embodiment shown in planes parallel to main planes. They could have a different orientation, be radial, rounded, oblique or the like.

Figure 3 shows a gasket 60 for sealing-tight fitting of the lid on a container, and an immersion tube which may be outside (61 a) or inside (61 b) the spigot 1 9.

A valve housing constructed in the manner described above requires substantially only the same space as a conventional valve housing but enables the aerosol to be filled from outside via the filling aperture 22. This was hitherto possible only with complex valve housings and a matching valve holder. Since the oriented indentations 4 do not obstruct the flow path through the intermediate spaces 25, filling with gaseous pressure media or propellants is possible, the gas being injected with maximum uniformity on to the surface of the active substance solution already contained in the aerosol. The use of a high pressure thus ensures very deep turbulence or foaming of the active substance solution, which creates a very large surface through which the solution rapidly absorbs the gas.This obviates or greatly reduces the building up of a high pressure, more particularly a high maximum pressure, in the aerosol with the risk of the same bursting. Filling.

tests show that the maximum pressure built up decreases with increasing pressure during filling with a gaseous pressure medium.

Also, the valve housing 1 is stable enough to withstand the pressure exerted by the pressure medium, but flexible enough to yield to this pressure, for example by absorbing the pressure by a slight downward movement of the valve housing with respect to the indentations 4. A polyamide valve housing 1 in particular satisfies these requirements.

With a valve according to the present invention, therefore, a single type of assembly machinery and filling equipment can be used for filling different kinds of aerosols previously needing different assembly machinery and different valve housings, gaskets and valve holders. When the invention is applied instead of the conventional valve housings, filling time is also reduced. Consequently, aerosol production costs, and the manufacturing and storage costs for the component parts, can all be reduced.

Claims

1. A valve for an aerosol, which valve comprises a valve holder having an end wall and a peripheral wall, a valve housing immovable relatively thereto, peripherally distributed inwardly directed indentations in the peripheral wall engaging beneath a bead on the valve housing, the latter having an annular clamping rim, and a gasket for sealing off an outlet duct, the gasket being clamped between the rim and the end wall, having an edge portion projecting beyond the clamping zone and having a peripheral edge, a filling aperture being provided only inside the clamping rim having the end wall and the gasket being adapted to lift away from the end wall in response to filling pressure, to form a filling path, radially extending and substantially axially parallel intermediate spaces being provided to increase the cross-section of the filling path in the region of the bead, a plurality of projections being distributed symmetrically over the periphery of the valve housing, projecting radially from the outer wall, the intermediate spaces being provided between the projections, and the indentations engaging beneath the projections and between the intermediate spaces on the valve housing outer wall.

2. A valve according to Claim 1, wherein the indentations are each situate near a tangential surface.

3. A valve according to Claim 1 or 2, wherein the valve housing wall is of thickened construction in the region of the intermediate spaces.

4. A valve according to Claim 3, wherein the thickened region on the outer wall is symmetrical with respect to the associated intermediate space.

5. A valve according to Claim 3 or 4, wherein the thickened region on the inner wall is symmetrical with respect to the associated intermediate space.

6. A valve according to any one of the preceding claims, wherein the end walls of the projections bounding an intermediate space extend in parallel relationship to a major plane of the valve housing through the centre of the intermediate space.

7. A valve according to any one of the preceding claims, which has four intermediate spaces and there are four projections.

8. A valve according to any one of Claims 1 to 6, which has six intermediate spaces and there are six projections on the bead.

9. A valve according to any one of the preceding claims, wherein the valve body has a polygonal inside section and the valve stem has a circular outside section inscribed in the polygon, the number of sides of the polygon being equal to the number of intermediate spaces, the polygon apices being situate at the centre of the thickened portions forming the bead projections.

10. Any novel feature or combination of features described herein.