A pressurised dispenser

Abstract

 A pressurised dispenser includes an elastic motor unit 2 and a pouch 1. The pouch 1 is filled with the product to be dispensed against the elastic resistance of the motor unit 2. The pouch 1 is divided into a number of chambers in fluid communication with at least one outlet 5. The pouch is arranged to fold back on itself in the region of the divisions between the chambers to form a substantially flat package for insertion in the elastic motor unit.
In an alternative embodiment the elastic motor unit comprises an air spring 2′ which is filled with gas under pressure. The pouch 1′ is contained within the air spring 2′ and is filled with the product to be dispensed against the resistance of the gas pressure acting on the pouch.

Description

[0001] The present invention relates to the packaging and dispensing of products under pressure, and in particular to the provision of an alternative to aerosol dispensers.

[0002] Widespread concern about the environmental damage associated with the fluorochlorocarbons commonly used as aerosol propellants has led to an interest in the development of alternative systems for dispensing fluids under pressure. Systems have been proposed in which a pouch for the product to be dispensed is received within an elastic sleeve or "motor unit". The pouch is filled with the product against the elastic resistance of the motor unit. In use, a valve fitted to an outlet in the pouch is operated to allow the force of the motor unit on the pouch to expel the product.

[0003] Known examples of such systems suffer a number of disadvantages. In particular it has been found difficult to dispense the product in an even, regulated fashion and also to ensure that there is not a significant residue of the product left at the end of a dispensing cycle. Attempts have been made to overcome these disadvantages by, for example, providing ribs on the pouch and/or additional sleeves around the pouch to control the manner in which it collapses. However these attempts have only been partially successful in alleviating the disadvantages and moreover add undesirably to the cost and complexity of the package.

[0004] According to a first aspect of the present invention, a pressurised dispenser assembly comprising a pouch for receiving the product to be dispensed and an elastic motor unit, is characterised in that the pouch is divided into a number of chambers in fluid communication with at least one outlet and is arranged to fold back on itself in the region of the divisions between the chambers to form a substantially flat package for insertion in the elastic motor unit.

[0005] The present invention provides a dispenser assembly of simple construction which offers excellent performance characteristics. The folded pouch in its unfilled state is readily inserted or removed from a motor unit and so the assembly is particularly suitable for use in a dispenser intended to be re-cycled having once been emptied. This, in combination with the low energy and material costs of the assembly, further enhances the ecological advantages of the assembly as compared with conventional aerosol dispensers.

[0006] Preferably the pouch comprises two opposing sheets of plastics material sealed together at their edges. Preferably the sheets are welded together along a number of laterally spaced weld lines extending longitudinally from one edge of the sheets towards an opposing edge, and spacers are interposed between the opposing sheets to provide channels for fluid communication.

[0007] According to a second aspect of the present invention an elastic motor unit for use in such a system comprises a plurality of annular bands arranged end to end and defining together a cavity for receiving a pouch containing the product to be dispensed, each band being arranged to expand or contract substantially independently of the or each adjacent band.

[0008] By constructing the elastic motor unit of a number of independent bands the present invention allows the forces developed by the motor unit to be controlled with far greater precision. In particular, it is possible to ensure that the unit as a whole will not produce any significant vertical vector forces.

[0009] Preferably the bands at either end of the motor unit are arranged to have co-efficients of elasticity greater than those of the or each band away from the ends of the motor unit.

[0010] The end bands are provided with a greater co-efficient of elasticity so that for a given amount of linear extention they develop a greater radial force than the intermediate band. Typically these end bands will have a thicker wall section and greater depth. The geometry of the end bands is arranged so that they develop vectors that oppose the vertical movement, that is movement normal to the radial direction, produced in the pouch by the intermediate bands.

[0011] According to a third aspect of the present invention, a pressurised dispenser assembly comprising a pouch for receiving the product to be dispensed and a motor unit is characterised in that the motor unit comprises a sealed outer bag containing the pouch and arranged to be filled with gas under pressure, in use the pouch being filled with the product against the resistance of the gas in the outer bag.

[0012] The third aspect of the present invention uses a motor unit in which the elasticity against which the pouch is filled is provided by a gas under pressure. The structure of the assembly is such that it is readily constructed from re-cyclable plastics material such a PET sheets. Moreover since both the bag and the pouch are of generally similar construction they can both be formed in a single integrated manufacturing process.

[0013] The pouch used in this aspect of the invention may comprise only a single chamber formed by two opposing sheets but alternatively may be formed from a plurality of interconnected chambers and be arranged to fold flat in the manner of the pouch used in the assembly according to the first aspect of the present invention.

[0014] A pressure dispenser assembly in accordance with the present invention is now described in detail with respect of the accompanying drawings in which:

Figure 1 is a longitudinally sectioned side elevation;

Figure 2A & 2B are views of the pouch during and after manufacture;

Figure 3A to 3E are a plan and perspective views showing the manufacture of the motor unit;

Figure 4A to 4D are cross sections through the pouch;

Figure 5 is a plan showing alternative layouts of the chamber in the pouch; and

Figures 6A to 6C show an alternative embodiment.

[0015] A pressurised dispenser assembly comprises a pouch 1 received within an elastic motor unit 2. The pouch 1 includes an outlet 3 for connection to a valve unit 4. In use, the pouch 1 is filled with the product to be dispensed, causing radial expansion of the motor unit 2. The outlet 3 is then sealed to the valve unit 4. Subsequently when the valve unit 4 is operated the pressure generated by the motor unit 2 causes the product to be expelled via the outlet 3.

[0016] The construction of the pouch is shown in greater detail in figures 2A and 2B. The pouch is formed from two opposing sheets of plastics material, which in the present example is a metallised PET film able to resist 120 psi and to provide a barrier against light oxygen and water. A valve coupling 5 which in the completed pouch provides the outlet 3, is formed on one of the sheets. Laterally separated spacers 6 are welded to the same sheet towards its longitudinal edge. A second PET sheet is then fed to the primary sheet and sealed to the primary sheet by welding along its edges. Further weld lines W are then formed extending from one of the sealed edges longitudinally towards the opposing edge. The weld lines W define a number of chambers. The precise structure and configuration of the chambers is varied according to the manner in which the pouch is to be used, as described in further detail below. The pouch is then folded about the weld lines W concertina-fashion. Finally the trailing edge of the continuously-fed sheets is cut and sealed. The pouch then has the flat elongate configuration shown in figure 2B and is ready for insertion in the motor unit and subsequent filling.

[0017] The motor unit 2 comprises a number of annular bands 7 of elastomeric material joined together by webbing to form a continuous tubular cavity which receives the pouch 1. The manufacture of the elastic motor unit 2 is shown in figures 3. The annular bands are continuously moulded on a rotary cavity mould. The moulding assembly comprises a cavity mould A1 a second cavity mould block A3 and a intermediate core A2 all arranged around a wheel. The continuous lengths of tubular moulding output by the mould are folded as shown in Figure 3B. The moulding may be loaded in a cartridge for use in the subsequent stages of the manufacture process. In those subsequent stages the moulding is cut into discrete units of appropriate lengths to form the motor units. A register mark maybe formed on each motor unit to enable accurate re-cycling. The pouch 1 is then inserted in the cavity of the motor unit 2 with the portion of the pouch bearing the outlet 3 projecting clear of one end of the motor unit. A valve 4 is then assembled to the outlet and the entire assembly fitted in a suitable cannister 8.

[0018] As the pouch 1 is filled with the product to be dispensed it expands and at least partially unfolds against the resistance of the elastomeric annular bands. The initial expansion is effected by a gas pumped into the product pouch. In the present example the gas volume is approximately 10% of the product volume. This initial pre-filling with gas facilitate the initial opening of the pouch and chambers and expands the motor unit to the point of linear expansion. Then during the dispense cycle the presence of the prefilled gas ensures that all the product is dispensed from the pouch within the motor units range of linear operation, ensuring that the products is dispensed uniformly with only a minimal residue left at the end of the dispensing cycle. Although gas pre-filling is the preferred method of achieving these properties, alternatively a separate gas chamber may be formed in the pouch as a sealed unit or as a further alternative a mechanical spacer such as a rod or bar maybe inserted between the pouch and the motor assembly or sealed into the pouch.

[0019] As shown in Figure 1 the annular bands at the ends of the motor unit are thicker and of greater depth than the bands away from the ends. Typically the end bands will be approximately 3mm thick whereas the bands away from the ends are only 2mm thick. The thicker bands at the end of the motor unit generate forces with a component in the longitudinal direction. This arrangement is effective to prevent movement of the pouch within the motor assembly and to stop pouch slippage.

[0020] The expansion of one of the annular bands is shown in Figure 4. Figure 4A shows the band in its initial relaxed position. Non-linear expansion occurs until the point illustrated in Figure 4B is reached, this occurring at substantially 10% of the total filled volume of the assembly. The expansion from A to C is effected by the pre-filled gas which is typically air. The product is subsequently fed into the pouch expanding the motor unit linearly to its fully extended position shown in Figure 4D. In the present example the full volume of the unit is 220cc comprising 200cc product and 20cc of the pre-filled gas.

[0021] As noted above, by suitable positioning of the weld lines W the chambers within the pouch may be formed in a number of different configurations. Some of the different possible layouts are shown in Figure 5. Layouts RF1-RF6 are suitable for a pouch which is to be re-filled as part of a closed loop product cycle. To prefill a bag the following functions must be performed:

(a) purging of the pouch

(b) refill of the pouch

To achieve (a) a flow of the purging medium through the pouch is necessary and so the pouch must have both an inlet and outlet valve. The use of two valves also allows faster filling with gas in, e.g. a pre-inflation stage, with air venting out of the second valve. In the RF3 layout a sealed chamber is provided with a third valve. This chamber functions as an air spring or filler which is entirely separated from the product by the laminate walls. With the layout of RC4 and RC5 the pouch is arranged to be folded concertina-fashion about fold lines normal to the longitudinal axis. The alternative layouts RC1-RC5 are suitable for a package which is to be reclaimed, that is the dispenser is disassembled after use and the component materials fed back into the manufacturing process to produce further units. The pouch and the motor unit are designed for easy assembly and disassembly so that a pack can be re-used or re-cycled indefinitely. In practice the number of cycles of re-use will be limited by the eventual deterioration of the elastic motor unit.

[0022] Figure 6 shows an alternative embodiment. In this embodiment the elastic motor unit is provided by an air spring rather than by solid elastomeric bands as in the first embodiment. The air spring is provided by a sealed outer bag 2′ which is filled with atmospheric gases or CO₂ at approximately 4 volumes pressurisation. A pouch 1′ for the product is sealed within the outer bag 2′ and is filled with the product to be dispensed against the elastic resistance provided by the pressure of the gas in the outer bag acting on the pouch.

[0023] Both the outer bag 2′ and the inner pouch 1′ are formed from respective pairs of PET sheets welded or otherwise bonded together around their perimeters. The regions where the sheets of each pair are bonded to each other are indicated with an S in Figure 6A.

[0024] As shown in Figure 6B one of the sheets 10 making up the pouch 1 is bonded to the inner surface of one of the walls 11 of the outer bag 2′.

[0025] The assembly is manufactured as follows: A sheet 10 is fed from a reel of material. A circular aperture is cut in a sheet 10a at the appropriate position. A PET injection moulding forming an inner collar 14 is welded or bonded to the sheet 10a on the seal flange such that the moulding protrudes through the aperture. The size of the aperture is such that an annular area is left exposed. The sheet 11a forming the outer bag is pierced as described above but with a smaller aperture. The outer sheet is welded or bonded to the PET moulding on the exposed area of the seal flange. A second PET moulding forming an outer collar 15 is welded to the reverse of the assemby so that the seal area is mechanically supported by the PET flanges. The inner bag is completed by attaching a second sheet 10b and sealing around the perimeter of the two sheets to form a closed structure. The outer bag is completed by attaching a second sheet 11b and sealing around the perimeter such that the inner bag is encapsulated in the larger bag.

[0026] Additional reinforcements are provided in the pouch and the bag to prevent peel. In the particular embodiment shown a fitting 12 made of solid PET is used to fasten the pouch to the bag and also incorporates a coupling 13 which in use is fitted to a valve 4 of the type discussed above in relation to the first embodiment. As in the first embodiment the entire assembly is then fitted in a suitable cannister 8.

[0027] In use, after the pressurisation of the outer bag 2′ the inner pouch 1′ is filled with the product to be dispensed against the resistance of the gas in the outer bag until the inner bag is under a combined pressure of 5 volumes (75 psi). The energy taken to fill the pouch 1′ is released when the product is dispensed. When the pouch 1′ has been emptied of product, the dispenser can be re-cycled by opening the cannister, removing the bag and pouch, the materials of which can then be reclaimed, and fitting a new bag/pouch assembly to the cannister.

[0028] Various gases may be used to pressurise the bag 2, when atmospheric gases or CO₂ are used then the re-cycled PET material of the plastics sheets is metallised.

[0029] Although in the embodiment shown in the Figures, the pouch used with the air spring comprises just a single chamber, the air spring may also be used with a pouch as described above with respect to the first embodiment so that it is divided into a number of chambers and arranged to fold flat prior to filling.

Claims

1. A pressurised dispenser assembly comprising a pouch (1′) for receiving the product to be dispensed and a motor unit (2′) characterised in that the motor unit (2′) comprises a sealed outer bag containing the pouch and arranged to be filled with gas under pressure, in use the pouch (1′) being filled with the product against the resistance of the gas in the outer bag.

2. An assembly according to claim 1, in which each of the outer bag (2′) and the pouch (1′) comprise opposing sheets (10,11) of plastics material sealed together at their edges.

3. An assembly according to claim 1 or 2, in which the pouch (1′) is fastened to the outer bag (2′) by a fitting (12) including an outlet (5′) for fluid communication between the pouch (1′) and the exterior of the bag.

4. An assembly according to any one of the preceding claims, in which the outer bag (2′) is arranged to be filled with gas at substantially 4 volumes pressure, and the pouch when filled is under substantially 5 volumes pressure.

5. An assembly according to any one of the preceding claims, in which an outer surface of one wall of the pouch is bonded to an inner surface of one wall of the outer bag (2′).

6. A pressurised dispenser assembly comprising a pouch (1) for receiving the product to be dispensed and an elastic motor unit (2), characterised in that the pouch (1) is divided into a number of chambers in fluid communication with at least one outlet and is arranged to fold back on itself in the region of the divisions between the chambers to form a substantially flat package for insertion in the elastic motor unit (2).

7. An assembly according to claim 6, in which the pouch (1) comprises two opposing sheets of plastics material sealed together at their edges.

8. An assembly according to claim 7, in which the two opposing sheets are welded together along a number of laterally spaced weld lines extending longitudinally from one edge of the sheets towards an opposing edge and spacers (6) are interposed between the opposing sheets to provide channels for fluid communication.

9. An elastic motor unit (2) for use in a pressurised dispenser assembly comprising a plurality of annular bands (7) arranged end to end and defining together a cavity for receiving a pouch (1) containing the product to be dispensed, each band (7) being arranged to expand or contract substantially independently of the or each adjacent band.

10. An elastic motor unit according to claim 9, in which the bands (7) at either end of the motor unit are arranged to have coefficients of elasticity greater than those of the or each other band away from the ends of the unit.

Drawing