GB2153011A - System for the pressurisation of spray containers - Google Patents

Abstract

A spray container or aerosol 1 has a spray valve 2 and, internally, is provided with a butyl rubber sleeve 4 surrounding a textile mesh sleeve 7 and a core 5. When an outer chamber 6 is filled with a liquid to a level 17, that liquid is progressively transferred to an inner chamber (inside the sleeve 4) by capillary action through the sleeve 7 with expansion of the sleeve 4 (see Fig. 2) against the resilient opposition of the latter. Upon operation of the spray valve 2, the expanded sleeve 4 will contract and eject the liquid which it contains. The container 1 is refillable and no propellant gas is required. An inner sleeve 8 can be located between the core 5 and the textile sleeve 7, and the bottom of the core 5 and sleeve 8 are so constructed as to facilitate the ascent of the liquid. <IMAGE>

Description

SPECIFICATION System for the pressurisation of spray containers This invention refers to a system for the pressurisation of spray containers, which system revolutionises the standard technology in this field, giving such containers a self-sufficient character, i.e. by pressurising them automatically without the requirement of a pressure supply from an external source.

There are on the market many products which are used in spray form, themselves packed in containers which are called "sprays" or "aerosols" where the product to be used is accompanied by a pressurised gas which acts as a propellant so that, when a spray valve is operated, the internal container pressure causes the expulsion of the product in spray form.

Many products are marketed in this format, including, by way of example, perfumes, lacquers, liquid insecticides, paint, oils, and so on.

As is known, the gases which are used to pressurise these containers present two principal problems. One of these is by their accumulation in the upper layers of the atmosphere, which accumulation has negative effects on the formation of ozone, so that the progressive reduction of this latter gas involves an increase in the "greenhouse" effect at those levels, constituting a long term environmental risk. On the other hand, these propellant gases are also normally inflammable and dangerous so that, as is well-known, the conainers must carry warnings against their exposure to temperatures above 50 C and, even when empty, they must not be punctured nor thrown on to fires.

The system proposed in this invention eliminates such pressurising gases, along with any others, thus substantially completely overcoming the foregoing problems: with this system, on the basis of a sealed container with only the product to be sprayed, sufficient internal super-atmospheric pressure is obtained spontaneously so that, when the spray valve is operated, the contents issue in a dosified spray form.

Given the foregoing, it is the main aim of the invention to use the system advocated to obtain receptacles containing liquids which will propel such liquids in spray form without the use of pressurising gases.

A further object of the invention is for these containers to be rechargeable, with the consequent benefit at the economic level in the marketing of such products.

Further advantages of the system will be self-evident from the following description.

The basis of the system is the creation inside a reciptacle of any convenient shape of two co-axial chambers by means of an elastic tubular body having a coefficient of elasticity which is sufficient to supply the internal chamber it forms with a pressure level which will expel the liquid product.

This tubular body is hermetically sealed around the spray head and is installed on a support core which should extend to close to the lower base of the reciptacle, but with the additional feature that, between the tubular body and the support core, which are restricted by a clamp at the bottom free end, there is a second tubular body, of textile lateral, which second body emerges in the direction of the outer chamber and which, therefore, interconnects the two chambers.

The capillary action of the textile tubular body creates an "absorption wick" which progressively transfers the liquid product from the outer to the inner chamber, in parallel with a deformation of the first tubular elastic body: this elastic tension, stored in the first tubular body, is what propels the liquid to the exterior when the spray valve is opened.

For practical use, the system requires certain structural accessories. Between the central core and the assembly of the two tubular bodies elastic and textile -- the insertion is required of an inner sleeve which divides the inside chamber into two sub-chambers, one housing the core and the other housing the textile material tubular body: they are connected by a perimeter alignment of micrometric drill holes close to the bottom end of the inner sleeve, so that the pressure generated by capillary absorption in the external sub-chamber is progressively transmitted to the internal sub-chamber until a limit point of balance is reached where both pressure levels are equal and, at all events, are greater than atmospheric pressure. This means that, when the spray head is operated and the valve opens, the liquid emerges in spray form.

The core should also be of a particular structure: the bottom end, at the level of the micrometric holes in the inner sleeve, should be of truncated conical shape, and its cylindrical lateral surface should have a number of longitudinal and parallel grooves to promote the creation of a Bernoulli effect when, in turn, facilitates the ascent of the liquid. The middle area of the core includes radial drill holes which interconnect said lengthwise grooves (which, as pointed out above, are located in the lower half) and the hollow interior of the upper half, through which the connection is made to the spray valve.

Obviously, as the liquid in the container is consumed, the pressure is lowered which reduces the effectiveness of the pressurising body: however, as the system allows the container to be refilled, all that is required, when deemed necessary, is to remove the spray head and to top the unit up with the liquid product.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a diagram of a spray container fitted with the pressurisation system which is the subject of this invention in a vacuum or low pressure condition and with internal compartmentalised elements thereof shown in partial cross-section, allowing a view of the internal core.

Figure 2 is a view similar to that of Figure 1, but in which the container is shown filled with liquid and a compartmentalising elastic tubular body has deformed and has created pressure by which to propel liquid to the exterior when a spray valve is operated, Figure 3 is a side elevation of the flexible tubular body and of elements which secure it to the spray valve, Figure 4 is similar to Figure 3, for a second, textile tubular body, likewise showing the assembly's lower restricting clamp, Figure 5 is similar to Figures 3 and 4 but shows the inner sleeve with a clear indication of the arrangement of micrometric holes, Figure 6 is a lateral elevated and quarter-section view of a core, which is fitted with the elements shown in Figures 3, 4 and 5 and which, together with these, is intended for coupling to the spray valve, Figure 7 is a cross-sectional detail of said core, showing its upper half, and Figure 8, finally, is a further cross-sectional detail of the core, this time of the lower half.

Referring to the drawings, it can be seen that the system proposed by the invention is based on the arrangement on a container -1- of any convenient shape, and with an appropriate spray head or valve -2- and means for practical connection 3-to the mouth of the container, of a tubular elastic body -4- in butyl rubber of a hardness rating 16 on the Shore D. scale, which body -4is attached to a core -5- connected to the spray valve -2- and is axially arranged inside the con tainer -1-so that the tubular body creates -4two coaxial chambers in the container -1-, one chamber --66- which is external in relation with the wall of the container -1- and one internal chamber, between the body -4- and the core In the inner chamber, specifically between the elastic tubular body --44- and the core -5-, there is a second tubular body -7- of textile material which forms an elastic mesh that is able to exert the same pressure both longitudinally and laterally.

This mesh should, in its textile section, be manufactured in fibre-free cotton weft and warp thread with the purpose of creating a capillary effect both vertically and horizontally of sufficient strength to cause the transfer of liquid from the external chamber --66- to the inner chamber against the resilient effect of the tubular body -4-so as to distort it as shown in Figure 2.

As a complement to the structure described, the proposed system requires the provision, between the second tubular body -7- (in textile material) and the core -5-, of a sleeve -8- made of P.P.R. material (polypropylene rubber) of Shore D.

hardness 5, which material gives the sleeve -8- an optimum degree of external and internal consistency and adaptability.

The bottom of the sleeve -8- is closed and, close to this bottom end, there are a number of micrometric and perimetrally aligned holes -9each of a diameter of some 0.1 mm. These holes -9- are drilled inwards, i.e. from the outside to the inside, so as to permit full entrance to a liquid whilst concurrently offering a high level of resistance to the escape of such liquid by acting as a "castanet" type valve.

In accordance with the structure described, the sleeve - is pressure-fitted onto the core -5- and is fastened with a complementary part -10- (Figure 5), so that the core --55- must have an expanded part at the top, as shown at -11- in Figure 6.

The complementary part-1O consists of a P.V.C. (polyvinyl chloride) cap which, at the same time as sealing the sleeve -8-, provides the hermetic seal required for the whole assembly when fitted with the one-piece connection --33- to the spray head -2-.

The mesh-formation body -7- is pressure-fitted on the assembly 58 and adapts perfectly to the P.P.R. sleeve - over its whole surface. For preferance, the bottom part of the mesh should be eyeless in order to fit perfectly over the sleeve 8.

Finally, the flexible tubular body -4- must be fitted: this may be done by a heating process or by some mechanical expansion method which allows for its correct placement in a position where it reaches a neck or upper expansion end -11- of the core -5. However, this assembly procedure must not create deformations in the elastic mesh of the body -7-.

All this pressure core assembly, together with the spray head or valve -2-, is fitted to the mouth of the container -1- in such a way as to be removable using a bayonet connection or some other known device in order to enable the con tainer -1-to be fitted.

The different elements making up the pressurising body i.e. the core -5, the sleeve -8-, the textile tubular body -7- and the elastic tubular body -4- are strengthened rigidly at the bottom and the last three of these components are fitted to perimeter grooving -12- of the core --55- with the aid of a pressure clamp -13-, this grooving -12- having a toothed profile in order to ensure a hermetic seal.

Special mention must be made of the core -5, which is machined either in a polyamide or, preferably, in P.V.C. (given that polyamides are highly hydroscopic). This core is hollow along its first lengthwise half and its top 5', as appears in the cross-section of Figure 7 and, on the outside it is formed with a series of fins --144- which mark parallel grooves for the liquid along the whole length of the core -5, including its solid bottom.

At the centre, these fins -14- have ports -15 which connect the periphery of the core --55- with the upper half of the hollow interior thereof.

Adjoining the perimetral grooving -12- at the lower end of the core -5, the core has a section -15 that is, in general, of truncated conical shape which, together with the fins --144-, as pointed out above, promotes a Bernoulli effect to lift the liquid.

According to the structural and operational system advanced, once the container -1- is filled to a predetermined level -17-with the liquid to be sprayed, the spray valve -2- is connected to the interior, forming a hermetic seal with the pressurisation body 4785.

As the butyl rubber elastic tube --44- is open at the bottom, through which the textile mesh of the body -7- emerges a short distance into the outer chamber --66-, the liquid held in that chamber 6 is admitted by capillary action, through a re striction -18-, and is unable to return, as a result of the known physical effect that is created in restricted capillary bowls. Thus, the whole mesh body -9- is soaked and increases in volume, with a consequent increase in pressure in both directions, i.e., towards the elastic tubular body which is deformed until reaching the configuration shown in Figure 2, and towards the inner sleeve -- &

This increased pressure, in conjunction with that created by the deformation of the elastic tube 14-- causes the liquid to pass through the micrometric drill holes --99- in the sleeve -8-, so as to reach the sleeve interior where the core -5- is housed.The displacement of the cotton mesh 7-- during this operational phase allows a simultaneous deformation of the sleeve -8- in the same direction, so as to create an internal reduced pressure region around the core - which is gradually filled by the liquid as it passes through the micrometric ports -7-, and which liquid rises until it reaches the ports -15-through which it passes into the hollow interior of the core -5- where it reaches the area of the spray valve -2-.

Simultaneously, as the internal space of the sleeve - is filled with liquid, the external and internal pressures in the unit gradually come into balance, although they are at all times higher than external atmospheric pressure, as pointed out above: this over-pressure is obtained by the tension caused by the three elastic members which go to make up the pressurising body.

In these conditions, operation of the spray head opens the valve -2- and, by Venturi effect, the liquid is released in spray form.

Logically, the efficiency of the pressurising body is greater the fuller the conainer: such efficiency will diminish progressively until a limit situation is reached when the container is substantially 25% full. At this point, the efficiency is nil, because the pressure created by the pressure body will not be sufficient to create a difference with atmospheric pressure.

Nevertheless, and as pointed out above, one of the basic features of the system lies in the fact that the container -1- can be refilled, so that all that is required is to top it up to the original level, when the unit will recover substantially its maximum operational efficiency.

Apart from the basic advantages which are derived from the pressurisation system that is the subject of this invention, it is clear that, with this system, the mechanisation of the container -1- is much simpler than that for a standard spray: this, together with the possibility of indefinite re-use of the container is another considerable advantage over the technology normally applied in this field.

It is not thought necessary to provide any further description for an expert in the matter to grasp the scope of the invention and the advantages which is produces.

The materials, shape, size and arrangement of the components are susceptible of variation, always provided that this does not alter the essential nature of the invention.

Claims (1)

1. A spray container pressurisation system wherein a container having a spray valve is compartmentalised by an elastic tubular body which forms two chambers, an outer one between said tubular body and the wall of the container and an inner one inside said tubular body, and wherein a core is provided in the inner chamber to secure said tubular body hermetically to the spray valve, and wherein a second tubular body, of textile material, is provided between said core and the elastic tubular body which second tubular body protrudes from the bottom of the elastic tubular body and acts as a transfer means, by capillary action, between the outer and inner chambers so that a liquid which is to be sprayed, and which is located in the outer chamber, is moved by said capillary action into the inner chamber, producing a deformation of the elastic tubular body, against its resilient opposition, so converting it into a pressure "pump" which, by way of elastic recovery towards its undeformed configuration, will eject said liquid to the exterior when the spray valve is opened.

2. A spray container pressurisation system according to claim 1, wherein, between the core and the second tubular textile body, there is a sleeve that is closed at its bottom and, near this point, is formed with a perimeter alignment of micrmetric orifices through which two sub-chambers defined by the sleeve are interconnected.

3. A spray container pressurisation system, according to claim 1 or 2, wherein said elastic tubular body is formed from butyl rubber of substantially 16 hardness on the Shore D. scale, and wherein the second textile tubular body is an elastic mesh which can pressurise with substantially the same effect both longitudinally and laterally, said textile being fibre-free cotton in weft and warp threads, and wherein the internal sleeve is made of a P.P.R.

material of substantially 5" Shore D. hardness.

4. A spray container pressurisation system, according to any preceding claim, wherein substantially the top half of the core is hollow and has, along its external surface, a number of fins which form parallel grooves, with a connection between said grooves and the hollow interior of the core through holes in the base of said grooves, said core comprising a truncated conical section close to its lower end, following which there is a groove for securing to the core bottom portions of the two tubular bodies, elastic and textile, with the as A spray container pressurisation system according to claim 2 or to either claim 3 or claim 4 when read as appendant to claim 2, wherein the micrometric ports in the sleeve which is directly fitted onto the core have a diameter of substantially 0.1 mm and are drilled inwards so that liquid may easily enter whilst its return is resisted in the manner of a castanet valve.

6. A spray container pressurisation system according to any preceding claim, wherein the elastic tubular body whch compartmentalises the inner and outer chambers is fitted over the second textile tubular body by a heating procedure or with the assistance of a mechanical expanding device so that the fitting operation does not produce deformations in the textile mesh.

7. A spray container pressurisation system according to any preceding claim, wherein said container is refillable.

8. A spray container pressurisation system substantially as hereinbefore described with reference to the accompanying drawings.

9. A spray container or aerosol when provided with a pressurisation system according to any preceding claim.