GB2078862A

GB2078862A - Spray head for pressurised dispensers and method of assembling such a spray head

Info

Publication number: GB2078862A
Application number: GB8120666A
Authority: GB
Original assignee: Aerosol Inventions and Development SA AIDSA
Current assignee: Aerosol Inventions and Development SA AIDSA
Priority date: 1980-07-04
Filing date: 1981-07-03
Publication date: 1982-01-13
Also published as: DE8119364U1; FR2486036A1; AU7242981A; FR2486036B1; IT1138398B; GB2078862B; ES271595Y; AU541057B2; ES271595U; ZA814406B; IT8122317A0

Abstract

A large-diameter spray head for a pressurised dispenser (e.g. an aerosol can) has a main body 1 with a tubular portion 2 for engaging the valve stem and leading to a long recess 4 terminating at the side of the button, and a separate assembly 5 comprising a pin 6 with a passage along it and a spray insert 9 on one end of the pin is forced into the passage. The insert seals into the outer end of the recess. The correct behaviour of the insert can be checked in the assembly 5, before it is inserted into the main body 1. <IMAGE>

Description

SPECIFICATION Spray head for pressurised dispensers and method of assembling such a spray head In pressurised dispensers (such as are commonly known as aerosols) the type of container that finds favour with the public is that in which the spray head or button has a relatively large diameter, capable of approaching or even exceeding the diameter of the container itself.

Such a spray head comprise an axial tubular portion for engaging the actuating stem of the valve or the valve member itself. This axial tubular portion is continued in a radial passage which leads into a break-up nozzle or insert situated in the side wall of the spray head. This radial passage has a diameter which is very small in relation to its length, such as to call for careful moulding and it restricts the speed of the moulding cycle.

Moreover, the core which forms the passages in the moulding has to be cooled. Its relative fragility leads to it having to be replaced frequently, putting the mould out of action.

Furthermore the mounting of the break-up insert requires that it be correctly placed in its recess, especially in the case of swirl-type nozzles: if it is put in place too violently, the swirl passages in the nozzle can become crushed, leading to partial obstruction and to poor spraying volume. If the insert is put in place too gently, it can allow liquid to pass around the swirl passages, inhibiting the effectiveness of the swirl system.

Correct assembly is checked on the finished spray head and those which fall outside the limits of tolerance are rejected.

There is a lack of reasonable proportion between the cause of rejection and the value of the article rejected.

The aim of the invention is to alleviate the above-mentioned drawbacks in the manufacture of the known spray heads.

According to the invention a spray head for a pressurised dispenser is characterised in that it comprises on the one hand a main body having a tubular portion for engaging the dispensing member of the valve, as well as a cylindrical recess leading to atmosphere and communicating with the tubular portion, and on the other hand an assembly comprising a cylindrical pin intersected by at least one longitudinal passage opening into the end faces of the pin, the outer end face of the pin being capped by a spray insert or nozzle and the body being inserted frictionally in the recess, the nozzle establishing an annular seal with the recess.

The passage in the pin can preferably be constituted by at least one groove formed in its external cylindrical wall.

To facilitate assembly on automatic machinery, the pin is preferably made of symmetrical form, each of its ends having two stepped shoulders of smaller diameter.

In one embodiment, the base end of the cylindrical recess has a projecting axial abutment which limits the insertion of the pin and a radial passage communicating with the tubular portion and opening between the projection and the cylindrical side wall of the recess.

According to another feature the orifice which communicates with the tubular portion opens into the cylindrical recess on the axis of the latter, the rear end face of the pin being intersected by a diametrical groove leading into the cylindrical wall of the pin.

Also according to the invention a method of the invention also has as its subject a process for mounting such a spray head is characterised in that one end of the pin is capped by a break-up insert or nozzle, the correct operation of the insert or nozzle, thus assembled, is checked, and the pin/nozzle assembly is then inserted with friction into the cylindrical recess in the body of the spray head.

Thus, with a spray head with a separate nozzle assembly according to the invention, the moulding of the head is facilitated by the fact that the small radial passage is replaced by the recess for receiving the pin of large diameter, thus avoiding in practice the frequent replacement of the tiny fragile cores and allowing internal cooling of the large core which now forms the recess for the pin. This fact leads to the moulding cycles no longer being restricted and they can in practice be doubled in speed as compared with the moulding of the classical type of button.

Furthermore the mounting of the inserts onto the pins to form subassemblies allows checking of the fluid behaviour of the nozzle/pin assembly before it is fitted to the spray head. In the event of rejection, it is only the defective parts that are rejected, that is to say, the insert and its associated pin and not the whole spray head assembly as was the case hitherto.

Moreover, the invention allows the production of spray heads in large numbers independently of the particular spraying characteristics, and the manufacture of pin/nozzle assemblies in large numbers with various characteristics, independently of the spray heads.

The spray head/pin/nozzle assembly can be made up according to the requirements of the customers.

It is therefore possible to reduce stocks, whilst still responding immediately to orders.

Finally the short length of the radial passage joining the recess for the pin to the tubular portion leading to the valve allows this passage to be formed down to very small diameters.

This allows spraying systems of diverse behaviour to be produced, thanks to the combination in the choice of diameters of entry and of exit from the pin, allowing expansion and stratification of the aerosol product before it reaches the break-up insert or nozzle, which produces an effect of sudden explosion of the droplets and better atomisation.

These advantages are particularly marked in the case of water-based aerosol solutions such as those using dimethylether as propellant as the fineness of the atomisation allows faster evaporation of the water contained in the aerosol product.

The invention will be better understood by study of the following detailed description and inspection of the accompanying drawings which illustrate, by way of non-limiting example, a number of embodiments of the invention.

Figure I is a diametrically sectioned elevation of a large spray button or spray head according to the invention.

Figure2 is a view similarto that of Figure 1, showing another embodiment.

The spray head or button illustrated in Figure 1 comprises a body 1 moulded from plastics material and having on its vertical axis a tubular portion 2 which engages a standard aerosol valve of the female type, such as that sold under the identifying mark AR 70 by Messrs. Aerosol Research & Development Ltd.

This tubular engaging portion communicates with a radial passage 3 leading into a cylindrical recess 4 which in its turn leads to atmosphere through the wall of the body 1. Inserted into the recess 4 is an assembly 5 comprising a cylindrical pin 6 having in it a longitudinal groove 7 opening into each end of the pin.

The outer end face 8 of the pin is capped by a classical spray break-up nozzle insert 9 of the swirl type.

The assembly 5 is inserted frictionally into the recess 4, sealing being ensured by the side wall 10 of the insert 9.

The pin 6 has two shoulders 11, 12 symmetrically at each of its ends. At the outer end of the pin 6 the insert 9 engages without any play against the shoulder 11, whilst the shoulder 12 comes into engagement with the face of the swirl system.

Atthe inner end ofthe pin 6, the shoulder 12' comes into engagement with an axial abutment 13 which defines the degree of insertion of the pin 6 into the recess 4.

The radial passage 3 opens between the abutment 13 and the wall of the recess 4, thus providing an annular space 14for expanding the liquid aerosol, between the base of the recess 4 and the rear end of the pin 6.

The spray head illustrated in Figure 2 is designed more particularly for male valves of the so-called "stem" type. Parts corresponding to those in Figure 1 carry the same reference numerals.

This head comprises a cylindrical body 1 having an axial tubular portion 2 for engaging the stem of the valve, an assembly 15 comprising a pin 16 capped by a nozzle insert 9. The pin 16 is intersected by two grooves 7 and 17, diametrically opposite each other, leading at the rear end into a transverse groove 18. The radial passage 19 leads annuiarly in this case into the base of the recess 4.

In this embodiment the pin 16 is asymmetrical, its front face having no transverse groove 18.

In both embodiments the recess 4 for the pin ends in a slightly bell-mouthed enlarged portion which facilitates mounting of the pin/nozzle assembly.

According to the flow or atomisation required, one can vary the diameter of the insert 9 as in known spray heads, but also one can vary the diameters of the radial passage 3 and of the grooves 7 and 17 as well as of the expansion chamber 14.

This confers, therefore, a high degree of flexibility in adapting the spray head to the spraying of different aerosol compositions.

It will be understood that the invention is by no means limited to the embodiments described and illustrated but is open to numerous modifications.

For example, one could replace the grooves 7 and 17 by passages passing through the pin 6.

Claims

1. A spray head or button for a pressurised dispenser characterised in that it comprises on the one hand a body made up of a tubular portion for engaging the dispensing member of the said valve as well as a cylindrical recess opening to atmosphere, in communication with the said tubular portion, and, on the other hand, an assembly comprising a cylindrical pin intersected by at least one longitudinal passage opening into the end faces of the pin, the outer end face of the pin being capped by a spraying nozzle or insert, the assembly being inserted with friction into the recess, and the nozzle or insert establishing annular sealing engagement with the recess.

2. A spray head according to claim 1 in which the passage in the pin is formed by at least one groove in its external wall.

3. A spray head according to claim 1 or claim 2 in which the pin has symmetrically at each of its ends two stepped shoulders of smaller diameter than the remainder of the pin.

4. A spray head according to any one of claims 1 to 3 in which the base of the cylindrical recess has a projecting axial abutment which limits the distance by which the pin is inserted, and a radial passage leading to the tubular portion and opening between the abutment and the cylindrical side wall of the recess.

5. A spray head according to any one of claims 1 to 3 in which the radial passage leading to the tubular portion opens into the cylindrical recess on the axis of the latter, the rear end face of the pin being intersected by a diametral groove leading into the cylindrical wall of the pin.

6. A spray head for a pressurised dispenser constructed and arranged substantially as described with reference to the accompanying drawings.

7. A process of assembling a spray head according to one of claims 1 to 6 in which a pin is capped by a spray nozzle or insert, the correct operation of the insert, as thus mounted, is checked, and the resulting pin/nozzle assembly is inserted with friction into the cylindrical recess in the body of the spray head.