GB2037378A

GB2037378A - Valve Assemblies for Pressurised Dispensers

Info

Publication number: GB2037378A
Application number: GB7938751A
Authority: GB
Original assignee: Aerosol Inventions and Development SA AIDSA
Current assignee: Aerosol Inventions and Development SA AIDSA
Priority date: 1978-11-17
Filing date: 1979-11-08
Publication date: 1980-07-09
Also published as: AU527581B2; FR2441778B1; GB2037378B; IT1122812B; ES245522Y; AU5280279A; FR2441778A1; DE7925897U1; ZA796066B; ES245522U; IT7925271A0

Abstract

In a valve assembly for a pressurised dispensing container (so- called aerosol container) the mounting cup 3 is made of non-metallic material and the actuating button 2 is permanently sealed to it, for example by ultrasonic welding. A flexible annular portion 15 or 15' of reduced thickness allows the movement of the button (downward or tilting) necessary to open the valve. The shell 4 may be permanently sealed to the mounting cup as well so that all three form a unitary assembly. The button has a hole 12 in its top face to allow "gassing" through a path including a clearance 13 around the stem and notches 14 in the rim of the shell 4. <IMAGE>

Description

SPECIFICATION Valve Assemblies for Pressurised Dispensers This invention relates to valve assemblies for pressurised dispensers, in particular for small hand-held pressurised dispensers such as those commonly known as aerosol containers.

The most widely known form of valve assembly comprises a valve shell containing a springloaded valve member or cup which is urged against a gasket through which protrudes a hollow actuating stem through which the product to be dispensed passes when the cup is pushed away from the gasket by actuation of the stem.

The protruding end of the stem carries an actuating button or so-called spray tip, and the shell is carried in a mounting cup which surrounds the stem and is secured to the shell to hold the gasket in place on the shell and simultaneously forms the means by which the valve assembly is mounted on a container.

In the known assemblies of this kind the mounting cup is generally of sheet metal and is secured to the shell by crimping. Where the product to be dispensed is of certain kinds, for example an insecticide, problems arise of corrosion of the metal, and also of denaturing of the product by contact with the metal. Another problem, arising where the valves are automatically assembled, is that of correct location of the gasket within the mounting cup during crimping.

It is known, during the manufacture of pressurised products, to fill the pressurising or propellant gas into the container through the valve. In one known method a so called "gassing head" engages and seals onto the button, pushing the button down so that the button makes a sealing engagement with the mounting cup. The gas then passes through holes provided in the button and through the mounting cup via a clearance provided around the stem. The effectiveness of the seal between the button and the mounting cup depends on the accurate manufacture of both these components and on accurate location and movement of the gassing head. In practice the seal at this point is far from perfect and there is a significant loss of gas.

The aim of the invention is to overcome these drawbacks and provide a valve assembly in which corrosion and denaturing problems can be reduced or eliminated and in which sealing between the button and the remainder of the valve assembly during "gassing" is perfect.

According to the invention there is proposed a valve assembly of the kind set forth in the second paragraph above, in which the mounting cup is of non-metallic material and is permanently sealed to the actuating button or spray tip, the connection between the button and the cup being sufficiently flexible to allow the movement of the button necessary to open the valve. Preferably it is also permanently sealed to the shell as well. In fact all these components may form together a unitary assembly. Thus at one stroke we have eliminated the problem of sealing between the button and the mounting cup during gassing, since these components are now together in one piece. Also by making the cup non-metallic we have eliminated corrosion. The button, cup and shell are preferably of thermoplastic material and may be made individually then welded together preferably ultrasonically.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a section through which a valve assembly according to the invention; Figure 2 shows the assembly of Figure 1 fitted onto a container and engaged by a gassing head; Figure 3 is a detail section of part of the button and mounting cup in a modification; and Figure 4 is a perspective view to a smaller scale of the valve shell.

The valve assembly 1 shown in Figure 1 comprises a button or spray tip 2 carried on a valve mounting cup 3 by which the assembly is mounted in an opening in the top of a container, and a valve shell 4. Within the shell 4 is a valve member or so-called valve cup 5, urged upwards by a spring 6 and connected to a valve stem 7 which has a radial hole 8 leading into its hollow interior. The upper end of the stem 7 fits into a socket 9 in the interior of the button 2, leading to a spray insert 10 through which the product from within the container is sprayed when the button is pressed to open the valve.

The valve member 5 is urged by the spring 6 into sealing engagement with a gasket 11 of suitable rubber or synthetic rubber material, this gasket surrounding the stem 7 and being clamped between the valve mounting cup 3 and the upper end of the shell 4.

This basic form of construction, so far described, is known, the mounting cup being made of sheet metal and the valve shell being held in place, simultaneously trapping the gasket, by inward crimping of portions of the wall of the mounting cup. In the construction according to the invention, however, the mounting cup is of plastics material, and the button, mounting cup and shell are welded together to form a one-piece structure. They are preferably made of a thermoplastic material that is capable of being welded by ultrasonic techniques, as this makes the welding operation simple. It will be noted that the button 2 has a hole 12 in its top face and there is a clearance 1 3 between the stem 7 and the mounting cup 3. In addition the shell 4 has vertical notches 14 (see Figure 4) around its upper end forming paths for a filling gas, as will be described later.

The lower part of the side wall of the button 2 has an annular portion 1 5 of reduced thickness, thin enough to be flexible so as to allow the button to be depressed, during gassing or in use, in relation to the mounting cup; below this portion is a thickened rim 1 6 by which the button is welded to the inside of a collar 1 7 on the mounting cup 3.

In the version illustrated in Figure 1 the flexible portion 15 forms a downward continuation of the side wall of the button; Figure 3 shows a modification in which, instead, a flexible portion 1 5' forms a step in this wall.

The valve shell 4 has a thickened rim 19 at its open upper end for welding into the mounting cup 3, and the notches 14 are formed in this rim. The outside diameter D of this rim 1 9 is equal to the inside diameter of a recess formed in the mounting cup 3 to receive it. The main body of the shell 4, shown at 19' is of a smaller outside diameter D', and has an inside diameter d', smaller than the inside diameter d of the portion 19. There is thus defined a shoulder 21, which carries an annular upwardly projecting rib 22 for engaging and forming a good seal with the gasket 11.

It will be appreciated the shell 4 can only be welded to the mounting cup 3 after insertion of the gasket 11, the stem 7, the valve cup 5 and the spring 6. The button 2 is preferably welded at the same time, although in theory, at least, it would be possible to weld the button to the mounting cup in a preliminary operation.

As shown in Figure 2, the valve assembly described is secured on a pressurised dispensing container 23 by means of an annular metallic collar 24. However it will be apparent that there is no contact between the metal of the collar and the contents of the container 23, even while the product is being dispensed.

To fill the container 23 with a propellant gas under pressure, a gassing head 25 is caused to engage and seal onto the top end of the button 2, depressing the button. The propellant gas passes through the hole 12 into the interior of the button and thence through the clearance 1 3. The pressure is such that it compresses the gasket 11, allowing the gas to pass radially outwards over the gasket and down through the notches 14 into the interior of the container. Some gas may also pass between the inner edge of the gasket 11 and the stem 7 and reach the container through the inside of the shell 4.

It will be appreciated that, as the button 2 is permanently sealed to the mounting cup 3, there can be no loss of gas at this point during gassing.

Thus it is only necessary for the gassing head to engage the top end of the button. However, the valve assembly described would still be used with the kind of gassing head that seals onto the mounting cup itself.

By virtue of the flexible portion 1 5 or 1 5' of the button, the valve assembly could be of the kind that operates by tilting of the button rather than a straight push.

Claims

1. A valve assembly for a pressurised dispensing container comprising a valve shell containing a spring-loaded valve member or cup which is urged against a gasket through which protrudes a hollow actuating stem through which the product to be dispensed passes when the cup is pushed away from the gasket by actuation of the stem, the protruding end of the stem carrying a button and the shell being carried in a mounting cup which surrounds the stem and is sealed to the shell to hold the gasket in place on the shell and simultaneously forms the means by which the valve assembly is mounted on the container, distinguished by the feature that the mounting cup is of non-metallic material and is permanently sealed to the button, the connection between the button and the cup being sufficiently flexible to allow the movement of the button necessary to open the valve.

2. A valve assembly according to claim 1 in which the button and mounting cup are both made of a weldable plastics material and are welded together.

3. A valve assembly according to claim 2 in which the button and mounting cup are welded together ultrasonically.

4. A valve assembly according to any one of claims 1 to 3 in which the shell is also permanently sealed to the mounting cup so that the button, shell and mounting cup form a unitary assembly.

5. A valve assembly according to any one of claims 1 to 4 in which the flexible connection is formed by an annular portion of the wall of the button of reduced thickness.

6. A valve assembly according to claim 5 in which the button carries a rim below the portion of reduced thickness, this rim being received in and sealed into a collar on the mounting cup.

7. A valve assembly according to claim 4 in which the shell has a thickened rim received in and sealed to a recess in the mounting cup and has an internal shoulder that locates the gasket.

8. A valve assembly according to any one of claims 1 to 7 in which the button has a hole in its top face and there is a clearance between the mounting cup and the stem to provide a gas path for use during filling of a container on which the valve assembly is mounted.

9. A valve assembly for a pressurised dispensing container substantially as described with reference to Figures 1, 2 and 4 of the accompanying drawings.

10. A valve assembly according to claim 9, modified substantially as described with reference to Figure 3 of the accompanying drawings.

11. A pressurised dispensing container fitted with a valve assembly according to any one of claims 1 to 10.