GB1603971A

GB1603971A - Aerosol valves and housings therefor

Info

Publication number: GB1603971A
Application number: GB557178A
Authority: GB
Original assignee: Metal Box PLC
Current assignee: Crown Packaging UK Ltd
Priority date: 1978-05-30
Filing date: 1978-05-30
Publication date: 1981-12-02

Description

(54) AEROSOL VALVES AND HOUSING THEREFOR (71) We, METAL Box LIMITED, of Queens House, Forbury Road, Reading RIG 1 3JH, Berkshire, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to valve assemblies for aerosol containers, and valves and valve housings therefor.

The invention particularly relates to such assemblies, valves and valve housings for aerosol containers of the kind in which propellant gas from the container headspace is mixed with the product as it passes through the valve to the spray head for dispensing.

The direct admixture of the propellant gas to the product in this way dilutes the product so that it emerges from the spray head as a fine spray.

It is known to achieve such admixture of propellant with product in the valve housing, and to that end it has been proposed to pierce the housing wall with a hole, commonly and hereinafter referred to as a "vapour phase tap", which is open to the container headspace and through which propellant gas may pass from the headspace to the interior of the housing.

The vapour phase taps hitherto proposed have been normal to the housing wall so as to impinge the propellant gas directly against the product flow or in alignment therewith.

Applicants believe, however, that by inclining the vapour phase tap in relation to the housing wall the emergent spray can be improved or modified in a desired manner.

For the avoidance of doubt, in the above paragraph and throughout the remainder of the specification the verb "incline" in relation to the (or each) vapour phase tap is intended not to include an angle of 90 within its meaning.

In accordance with the invention from one aspect there is provided a housing for the actuating valve of an aerosol container, which has a chamber along which a pressurised aerosol product may flow for later dispensing from a spray head, there being at least one vapour phase tap formed in the housing as an aperture through the housing wall, at its entry to the chamber the vapour phase tap being inclined to the chamberdefining surface of the housing wall so that gaseous propellant entering the chamber from the container headspace will, in use, have a component of velocity peripherally of the product flow through the chamber.

In accordance with the invention from another aspect there is provided a valve assembly for an aerosol container, which comprises a valve, and a mounting cup for said valve and adapted for peripheral attachment to the product-containing body of an aerosol container, the mounting cup having a boss at which it is formed with an aperture and the valve comprising:: (a) a housing as defined above wherein the chamber is defined by a tubular side wall of the housing and a bottom wall closing one end of the side wall, the bottom wall being formed with a passage by which the chamber is, in use, in permanent communication with the aerosol product, the said vapour phase tap being formed in the side wall, and a portion of the side wall at its end opposite the said one end thereof being received and secured within the boss; (b) an annular sealing gasket of elastomeric material interposed between the said opposite end of the side wall and the boss so as to close the chamber in opposition to the bottom wall: and (c) an actuator member disposed within the chamber and having a hollow stem which extends through the gasket and through the aperture in the boss to a free end upon which a said spray head may be fitted in communication with the stem interior passage, the stem having an opening communicating its interior passage with its outer periphery, and the actuator member being biassed away from the bottom wall of the housing so that normally the said opening is closed to the chamber by the gasket, but being movable against the bias along the chamber to open the opening to the chamber and so allow product flow through the chamber to the spray head.

The invention also provides a valve for a valve assembly as defined above.

In order that the invention may be more fully understood three embodiments thereof will now be described, by way of example, with reference to the acCompanying drawings. In the drawings: Fig. 1 shows an aerosol valve embodying the invention in central vertical section, when fitted to a mounting cup and having an actuating button and dip-tube attached; Fig. 2 shows the housing for the aerosol valve in central vertical section on the line II--II of Fig. 3; Fig. 3 is a plan view of the housing taken in section on the line Ill-Ill of Fig. 2; Fig. 4 is a view similar to Fig. 2 of the housing in a first modification; Fig. 5 is a view similar to Fig. 3 of the housing of Fig. 4; Fig. 6 is a view similar to Fig. 2 of the housing in a second modification; and Fig. 7 is a view similar to Fig. 3 of the housing of Fig. 6.

Referring in particular to Fig. 1 of the drawings, a valve for an aerosol container is conventionally attached to the aerosol cone (not shown) of the container by a metal mounting cup 10. In kriown manner the aerosol cone is double seamed to the product containing container body (also not shown).

The valve, generally denoted 11, comprises a plastics housing 12 having a chamber 34 defined by a side wall 37 and a bottom wall 38, an annular rubber sealing gasket 13, a plastics actuating member 14, and a compression spring 15 which biasses the actuating member in the upward direction as shown. The actuating member has a stem 16 which projects outwardly and upwardly through a hole formed in the mounting cup at a boss 18. The stem is undersized in relation to the hole to form an annular clearance 17 between the stem and the boss.

Also shown in Fig. 1 is a plastics actuating button 20 which is push-fitted onto the free upper end of the stem, and a plastics diptube 21 having its upper end push-fitted into a bore formed in the bottom end of the housing 11 and arranged to communicate the valve with the bottom end of the container body. Except as otherwise indicated the items 10, 12, 13, 14 and 20 are circular in cross section.

In greater detail, the valve is attached to the mounting cup 10 by crimped engagement of the latter underneath a frustoconical shoulder 22 on an enlarged top end portion 23 of the housing side wall 37. This crimping is effected around the base of the boss 18 at a number of spaced indentations one of which is shown and indicated at 24.

The gasket 13 is tightly held between a knife edge 25 formed around the top of the housing, and the annular top end 26 of the boss 18 around the clearance 17. Radially outside the knife edge 25 the housing is relieved at a further frustoconical shoulder 27 to leave an outer peripheral margin of the gasket which is normally free of the housing.

The gasket 13 also projects inwardly beyond the knife edge 25; it has its inner periphery received in a correspondingly shaped circumferential groove 50 formed in the actuating member 14 around the base of the stem 16. A blind longitudinal bore 30 extends along the whole length of the stem between a closed bottom end 31 and the top end of the stem within the button 20. A channel 33 radially formed in the stem communicates this bore 30 with the groove 50.

The part of the actuating member 14 lying below the gasket 13 is received, with clearance, in the housing chamber 34. It has a central boss 35 on its underside to provide radial location for the top end of the compression spring 15. The bottom end of the compression spring rests on the top free edges of four equally spaced rectangular lands 36 which project inwardly from the housing side wall 37 and upwardly from the housing bottom wall 38. The lands are individually backed by abutments 39 arranged todefine a lower limiting position for downward movement of the actuating member 14 as is shortly to be described. The abutments also serve to locate the bottom end of the compression spring 15 in the radial sense.

A hole 40 centrally formed in the housing bottom wall 38 between the inner free ends of the lands 36 communicates the chamber 34 with the top end of the dip-tube 21.

As is later to be described, the button 20 is designed to form a fine spray of aerosol product which is held in the container body.

In its front face 41 it has an insert 42 which is arranged in relation to an integral spigot 43 formed on the button 20 so as with the spigot to form a cylindrical channel 44 and four further channels 45. The insert is centrally formed with an orifice 46 through which the aerosol spray is to engage. The channels 45 radiate from the orifice 46 and communicate with the channel 44 at their radially outer ends. A further passage 47 formed within the button communicates the channel with the top end of the bore 30 in the stem 16.

A downwardly projecting skirt 48 is integrally formed around the bottom end of the button 20 and arranged to make sealing engagement with the boss 18 when the button, and thereby the actuating member 14, is depressed to the lower limiting position defined by the abutments 39.

To fill the container for use the product to be dispensed is inserted in the container body with the aerosol cone attached, and the mounting cup, already fitted with the valve 11, actuating button 20 and dip tube 21, is swaged in position on the aerosol cone.

The container is then filled with propellant by what is commonly known as the "through-button" filling method, that is to say, a filler head (not shown) is brought down in sealing engagement onto the button 20 so as to depress the button until a seal is made between the depending skirt 48 and the boss 18 as described above. A metered amount of the propellant from a source to which the filler head is connected then enters the container body under pressure via a path which comprises a pair of channels 49 in the button, the annular clearance 17 between the stem 16 and boss 18, and the interface between the top and outer peripheries of the gasket 13 and the opposed interior surfaces of the boss 18.The resistance presented to the liquid flow in the latter part of the path is substantially reduced by downward flexing of the unsupported outer margin of the gasket towards the frustoconical shoulder 27 on the housing 12, as is described and claimed in our U.K. Patent Specification No.

1534873, to which the reader' attention is directed. Two diametrically opposed flats 51 are formed on the outer periphery of the enlarged top end portion 23 of the housing so as to provide a low resistance path for product flow in that locality.

The depression of the actuating member 14 caused by the filler head causes the inner marginal area of the gasket within the knife edge 25 to flex downwardly into the chamber 34 and out of tight sealing engagement with the stem groove 50. This allows for further flow of propellant from the filler head to the container body through the interface between the interior periphery of the gasket and the actuating member 14. Such further flow is via the chamber 34, the hole 40 in the housing bottom wall 38, and the dip tube 21.

It may pass between the filler head and the chamber 34 either via the channels 49 and clearance 17, or via the items referenced 46, 45, 44, 47, 30 and 33 in sequence.

Because of the various alternative flow paths provided for propellant flow between the filler head and the container body, charging with propellant can safely be achieved at high flow rates. After charging has been effected, the filler head is disengaged from the actuating button 20, whereupon the spring 15 biasses the actuating member 14 and button 20 upwardly to the position shown, so returning the gasket to its sealing position within the groove 50 and preventing escape of product or propellant from the aerosol container. The container is then ready for dispatch.

The arrangement as thus far described is conventional, the description being given for a full understanding of the embodiment. The arrangement differs from previous proposals in the particular arrangement of holes which are formed in the housing side wall 37 so as to communicate the head-space above the aerosol product in the container body with the chamber 34. Such holes are commonly referred to as "vapour phase taps".

Referring now to Figs. 2 and 3 in conjunction with Fig. 1, the holes 55 are circular and three in number, and formed in the housing side wall 37 below its enlarged top end portion 23. They are disposed with their axes in a common plane which is transverse to the central axis XX of the housing. They are regularly spaced around the side wall 37 at 120 intervals, being equally inclined to the side wall 37 so as each to enter the chamber 34 at a tangent to the chamber-defining inner surface 56 of the side wall.

To use the container the operator depresses the button 20 against the action of the spring 15, so uncovering the channel 33 to the chamber 34 by downward flexing of the inner margin of the gasket 13. Product from the container body can therefore pass to the spray orifice 46 under pressure from the propellant, via the dip tube 21, hold 40, chamber 34, channel 33, bore 30, passage 47 and channels 44, 45. In passing through the chamber 34 the product is mixed with propellant vapour from the container headspace entering through the holes 55. By virtue of the inclinations of the holes 55, the propellant imparts a swirl to the product as it passes up the chamber 34. The swirling action ensures a fine spray from the spray orifice 46 by throttling the flow of product and/or providing effective mixing of propellant with product. Moreover, it possibly tends to reduce variations in flow rate.

Figs. 4 and 5 show a modified housing 12 in which the holes 55 are located in the enlarged top end portion 23 of the side wall 37 to impart a swirl to the aerosol product as it leaves the chamber 34. As before, the holes enter the chamber 34 tangentially. In order to ensure freedom for the propellant vapour from the head-space to enter the holes 55, a flat is formed on the top end portion 23 at the entrance of each hole. These flats also provide the same function as the flats 51 (Figs. 1, 2) in relation to propellant charging as previously described; the reference numeral 51 is therefore again used.

Figs. 6 and 7 show a further modification in which the holes 55 alternate with the lands 36 and abutments 39 at the bottom end of the side wall 37. Four holes 55 are therefore provided. As before they are centred on a common transverse plane in relation to the central axis XX at the housing 12". They are each inclined in relation to the respective normal to the side wall 37, but at a smaller angle of inclination than in the previous embodiments. The lands are themselves in dined so as substantially to lie on a cylindrical envelope, each hole 55 being disposed so as to direct propellant towards the gap formed between the two lands on either side.

Rather than being wholly tangential to the side wall 37, the holes 55 may be orientated so as to lie with their axes intermediate the tangential and the normal directions, the orientation being chosen to achieve a desired relationship of direct (i.e. normal) impingement and swirl components of the propellant in relation to the flow of product.

Furthermore, although in the illustrated embodiments each hole 55 is disposed with its central axis in a transverse plane in relation to the housing, it may in some applications be found desirable to direct a hole 55 so that it has an axial component of direction in relation to the housing, so as to cause the propellant to enter the chamber 34 with a velocity component aligned with, and in the same sense as, the product flow.

In the described arrangements the holes 55 are arranged in a single coplanar group.

However, this is not essential; if desired, some or all of the holes may be axially spaced along the housing in relation to one another. They may be inclined at differing angles in one or both of the transverse direction and the axial direction, and so may be arranged to impart counter-rotary. swirls to the product.

Although circular section holes 55 are described and shown, holes 55 of noncircular section (e.g. oval) may be used if desired.

Although three or four holes 55 are provided for the described arrangements, a greater or lesser number of holes (e.g. one, two or five) may be used.

The invention has wide application to aerosol valves having vapour phase taps to admit gaseous propellant to the liquid product passing to a spray head. It is not limited to valves adapted for any particular kind of propellant filling operation such as the through-button filling of the described embodiments, and the valve mechanism itself may vary widely.

A particular application of the invention is for aerosol containers having an alcoholbased product with a hydrocarbon (e.g.

butane) propellant, and water to reduce the flammability of the emergent spray. Such a formulation typically has alcohol/hydrocarbon/water ratios of 5:2:3 by weight.

WHAT WE CLAIM IS: 1. A housing for the actuating valve of an aerosol container, which has a chamber along which a pressurised aerosol product may flow for later dispensing from a spray head, there being at least one vapour phase tap formed in the housing as an aperture through the housing wall, at its entry to the chamber the vapour phase tap being inclined to the chamber-defining surface of the housing wall so that gaseous propellant entering the chamber from the container headspace will, in use, have a component of velocity peripherally of the product flow through the chamber.

2. A housing according to claim 1, wherein the chamber is defined by a tubular side wall of the housing and a bottom wall closing one end of the side wall, the bottom wall being formed with a passage by which the chamber is, in use, in permanent communication with the aerosol product, the said vapour phase tap being formed in the side wall.

3. A housing according to claim 2, wherein the vapour phase tap enters the chamber tangentially with no axial component of velocity.

4. A housing according to claim 2, wherein the vapour phase tap enters the chamber so that the gaseous propellant has a component of velocity in the direction of, and in the same sense as, the product flow.

5. A housing according to claim 2 or claim 4, wherein transversely of the product flow through the chamber the vapour phase tap enters the chamber between the tangent and the normal to the side wall.

6. A housing according to any claim of claims 2 to 5, which includes a plurality of the said vapour phase taps spaced regularly around the side wall and entering the chamber in a common transverse plane.

7. A valve assembly for an aerosol container, which comprises a valve, and a mounting cup for said valve and adapted for peripheral attachment to the product-containing body of an aerosol container, the mounting cup having a boss at which it is formed with an aperture and the valve comprising: (a) a housing as claimed in any claim of claims 2 to 6 having a portion of the side wall at its end opposite the said end thereof received and secured within the boss; (b) an annular sealing gasket of elastomeric material interposed between the said opposite end of the side wall and the boss so as to close the chamber in opposition to the bottom wall; and (c) an actuator member disposed within the chamber and having a hollow stem which extends through the gasket and through the aperture in the boss to a free end upon which a said spray head may be fitted in communication with the stem interior passage, the stem having an opening communicating its interior passage with its outer periphery, and the actuator member being biassed away from the bottom wall of the housing so that normally the said opening is closed to the chamber by the gasket, but being moveable

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. dined so as substantially to lie on a cylindrical envelope, each hole 55 being disposed so as to direct propellant towards the gap formed between the two lands on either side. Rather than being wholly tangential to the side wall 37, the holes 55 may be orientated so as to lie with their axes intermediate the tangential and the normal directions, the orientation being chosen to achieve a desired relationship of direct (i.e. normal) impingement and swirl components of the propellant in relation to the flow of product. Furthermore, although in the illustrated embodiments each hole 55 is disposed with its central axis in a transverse plane in relation to the housing, it may in some applications be found desirable to direct a hole 55 so that it has an axial component of direction in relation to the housing, so as to cause the propellant to enter the chamber 34 with a velocity component aligned with, and in the same sense as, the product flow. In the described arrangements the holes 55 are arranged in a single coplanar group. However, this is not essential; if desired, some or all of the holes may be axially spaced along the housing in relation to one another. They may be inclined at differing angles in one or both of the transverse direction and the axial direction, and so may be arranged to impart counter-rotary. swirls to the product. Although circular section holes 55 are described and shown, holes 55 of noncircular section (e.g. oval) may be used if desired. Although three or four holes 55 are provided for the described arrangements, a greater or lesser number of holes (e.g. one, two or five) may be used. The invention has wide application to aerosol valves having vapour phase taps to admit gaseous propellant to the liquid product passing to a spray head. It is not limited to valves adapted for any particular kind of propellant filling operation such as the through-button filling of the described embodiments, and the valve mechanism itself may vary widely. A particular application of the invention is for aerosol containers having an alcoholbased product with a hydrocarbon (e.g. butane) propellant, and water to reduce the flammability of the emergent spray. Such a formulation typically has alcohol/hydrocarbon/water ratios of 5:2:3 by weight. WHAT WE CLAIM IS:

1. A housing for the actuating valve of an aerosol container, which has a chamber along which a pressurised aerosol product may flow for later dispensing from a spray head, there being at least one vapour phase tap formed in the housing as an aperture through the housing wall, at its entry to the chamber the vapour phase tap being inclined to the chamber-defining surface of the housing wall so that gaseous propellant entering the chamber from the container headspace will, in use, have a component of velocity peripherally of the product flow through the chamber.

against the bias along the chamber to open the opening to the chamber and so allow product to flow through the chamber to the spray head.

8. A valve assembly according to claim 7, wherein the or each said vapour phase tap is formed in the end portion of the housing side wall.

9. A valve assembly according to claim 8, wherein the end porton of the housing is enlarged in relation to the remainder of the housing to form a shoulder part way down the housing, and the valve is secured to the mounting cup by engagement of the mounting cup with the shoulder.

10. A valve assembly according to claim 9, wherein the vapour phase tap is communicated with the head space by a flat formed on the end portion of the housing at the entrance of the vapour phase tap.

11. A valve assembly according to claim 7, wherein the or each said vapour phase tap is formed in the housing side wall between the end portion of the side wall and the housing bottom wall.

12. A valve assembly for an aerosol container, substantially as herein described with reference to Fig. I to 3 of the accompanying drawings.

13. A valve assembly for an aerosol container, substantially as herein described with reference to Figs. 1 to 3, and as modified in accordance with Figs. 4 and 5, or Figs. 6 and 7, of the accompanying drawings.

14. A valve for a valve assembly as claimed in any claim of claims 7 to 13.

15. A housing for the actuating valve of an aerosol container, substantially as herein described with reference to Figs. 2 and 3, or Figs. 4 and 5, or Figs. 6 and 7 of the accompanying drawings.