EP0134122A1

EP0134122A1 - Dispenser nozzle

Info

Publication number: EP0134122A1
Application number: EP84305257A
Authority: EP
Inventors: John Maxwell Borland; Harold Crooks
Original assignee: Precision Valve Australia Pty Ltd
Current assignee: Precision Valve Australia Pty Ltd
Priority date: 1983-08-04
Filing date: 1984-08-02
Publication date: 1985-03-13
Also published as: JPS60110364A; ZA845917B; BR8403909A

Abstract

A nozzle for dispensing a liquid for use in trigger actuated sprays or aerosol sprays. The nozzle (10) comprises a body (11) having a convex, preferably hemispherical, face (14), a cap member (17) overlying the convex face of the body and having a concave, preferably hemispherical inner face (18) lying in close proximity with the convex face of the body and defining therebetween an enclosed space (19). A discharge outlet (21) extends through the cap member (17) at a point adjacent its centre and a liquid inlet duct (22) opens into the enclosed space (19) adjacent an edge thereof.

Description

The present invention relates to a nozzle for use in dispensing liquids in an atomised form under applied pressure.
Such nozzles are widely used in aerosol containers and the so- called pump sprays in which a hand actuated pump compresses a liquid to effect its discharge through a fine orifice to induce atomisation.
The present invention provides a nozzle for dispensing liquids in an atomised form under pressure, comprising a body having a convex face, a cap member overlying the convex face of the body and having a concave face lying in close proximity with the convex face and defining therebetween an enclosed space, a discharge outlet extending through the cap member distal to an edge of the said space, and a liquid inlet duct opening into the said space proximal to an edge thereof.
Such a nozzle can provide good atomisation over a wide range of inducing pressures and, in preferred embodiments at least, good atomisation at low pressures.
Such an arrangement also has the advantage that the liquid to be atomised and the gas causing the atomisation may be kept separate until almost the instant of atomisation. This allows the atomisation of liquids which in, conventional atomising nozzles, can cause swelling of the plastics material used in the construction of the valve or pump controlling the applied pressure.
Nozzles according to this invention have particular application in three distinct types of situations. There is firstly the situation in which a liquid is sprayed purely by application of pressure directly to the liquid to discharge it through the nozzle. This pressure may be applied manually directly to the liquid or by manual compression of air, or by a propellant gas which is insoluble in the liquid such as a compressed gas. In this arrangement there is no requirement for a separate gas inlet duct to introduce a gas into the nozzle. The second situation applies where a, preferably low, gas pressure is applied through a gas inlet duct into the nozzle which draws liquid into the nozzle by a venturi action and atomises it as it is discharged through the discharge outlet. The third situation is, in a sense, a combination of the first two and involves both the pressurized conduct of the liquid to the enclosed space and the presence of a gas inlet duct.
In preferred embodiments of the invention for use in the second and third situations outlined above a gas inlet duct is provided in the body. The gas inlet preferably opens into the convex face of the body in substantially axial alignment with the discharge outlet.
The gas inlet duct preferably includes an enlargement or plenum chamber immediately prior to entering the enclosed space between the body and the cap member. The presence of such a plenum chamber appears to produce a finer atomisation of the liquid than is obtained with a duct of uniform cross section. The plenum chamber is preferably spherical or substantially spherical in shape.
The body is preferably formed of a synthetic plastics material by injection moulding, however, other materials and other formation methods could be used. The face of the body is preferably hemispherical, however, other shapes of face which are arcuate in cross section could be used. The surface could in one extreme case be hemi-cylindrical. It is, however, preferred that the face of the body is curved in at least two planes i.e. that it forms part of the surface of a body of revolution formed by a curved line. The face of the body preferably has a radius of curvature of from 2 to 5 mm in at least one direction.
The cap member preferably screws onto or is otherwise affixed to the body to define the enclosed space between the convex face of the body and concave face of the cap member. The faces are preferably a uniform distance apart over their entire area so that the enclosed space is of uniform thickness. The convex face of the body and the concave face of the cap member can also be of different radii, such that the enclosed space is of non-uniform thickness. It is preferred that the enclosed space is thinner adjacent the discharge outlet than in areas around the periphery thereof. This latter arrangement provides improved atomisation for a given pressure or allows the same degree of atomisation to be achieved at a lower pressure.
The cap member is preferably so connected to the body such that the thickness of the enclosed space may be varied as this can increase and decrease the amount of liquid being sprayed from the nozzle. In another embodiment of the. invention the convex face of the body is formed on one end of a plug movable within a surrounding portion of the body. In this latter embodiment of the invention the thickness of the space may be varied by movement of the plug relative to the surrounding portion of the body. This adjustment of the cap member or plug can be used to seal off the nozzle for transport or prevent actuation of the nozzle by children. This is achieved by bringing the concave face of the cap member into contact with the convex face of the body and thereby eliminating the space and blocking the path between the liquid inlet duct and the liquid discharge outlet.
The nozzle preferably includes a plurality of liquid inlet ducts opening into the enclosed space. These inlet ducts are preferably evenly spaced around the periphery of the enclosed space. It has been found that the use of three or more liquid inlet ducts substantially improves the evenness of the cone of spray emitted from the nozzle, particularly under low gas pressure.
Hereinafter given by way of example only are preferred embodiments of the present invention described with reference to the accompanying drawings in which:-

Fig. 1 is a vertical sectional view through a dispensing nozzle according to this invention;
Fig. 2 is a vertical sectional view through another dispensing nozzle according to this invention;
Fig. 3 is a vertical sectional view through a further dispensing nozzle according to this invention;
Fig. 4 is a vertical sectional view through a further dispensing nozzle according to this invention;
Fig. 5 is a vertical sectional view through a still further dispensing nozzle according to this invention; and
Fig. 6 is a vertical sectional view through a still further dispensing nozzle according to this invention.

The dispensing nozzle 10 as shown in Fig. 1 is particularly adapted for use with a hand pump which will pressurise air to effect the spraying. The nozzle 10 includes a nozzle body 11 comprising a plug 12 and a surrounding body portion 13. The plug 12 is formed at one end with a hemispherical face 14. A gas inlet duct 15 extends through the plug 12, into the surrounding body portion 13, into the plug 12 and opens into the centre of the face 14. The gas duct 15 includes a spherical chamber 16 spaced inwardly of the body 11 a short distance from the face 14 and positioned between one end of the plug 12 and the surrounding body portion 13.
A cap 17 is connected to the body 11 and covers the face 14. The cap 17 has on ,its inner surface a hemispherical face 18 which is concentric with the. face 14 and lies in axial alignment with it and spaced a small distance from it. The faces 14 and 18 define between them a hemispherical, shell-like, space 19. A discharge opening 21 is provided in the cap 17 in axial alignment with the gas duct 15.
A liquid inlet duct 22 is provided to introduce a liquid to be atomised into the space 19. The inlet duct 22 includes a one-way valve 23 enabling liquid to be drawn up through a dip tube 24 from a container (not shown) while not allowing liquid to run back down the dip tube 21 into the container. The inlet duct 22 joins an axially extending duct 25 direct the liquid into the space 19 at the peripheral edges thereof.
In use,gas is directed along the gas inlet duct 15. This gas discharges through the discharge opening 21. As the gas is discharged it draws liquid from the space 19 by venturi action and atomises the liquid as it is discharged from the opening 21.
It has been found that this nozzle allows the production of finely atomised particles using relatively low gas pressures and relatively high spray rates.
The cap 17 is preferably connected to the body 11 by a screw thread so that the distance between the faces 14 and 18 can be adjusted. Typically this distance will be from 0.02 to 0.04 mm. Typically these faces 14 and 18 will have a radius of from 2 mm to 5 mm.
The nozzles shown in Figs. 2 to 6 are similar in principle to the nozzle 10 described with reference to Fig. 1. For this reason only the differences between these nozzles and the nozzle of Fig. 1 will be described. The same numbering will be given to similar functional parts in all of the drawings.
Figures 2 and 3 show arrangements which are in principle very similar to the arrangement shown in Fig. 1 but are particularly adapted for use in aerosol systems.
In Figure 2 there is no spherical chamber 16 included in the gas duct 15. It will be noted that the convex face 14 has a smaller radius of curvature than the concave face 18. The thickness of the space 19 thus diminishes as the space approaches the discharge opening 21. In this embodiment of the invention the inlet duct 22 communicates with an annular duct 26 which extends around the plug 12 and from which a plurality of ducts 25 extend to the space 19. In Fig. 3 the plug 12 protrudes from the surrounding body part 13 but in other respects the dispenser nozzle 10 is similar to those shown in Figs. 1 and 2.
The nozzle of Fig. 4 is also adapted for use in an aerosol container and includes the cap 17 formed integrally with the surrounding body portion 13. The convex surface 14 of the body 11 is formed at one end of the plug 12. The gas and liquid inlet ducts 15 and 22 run through the surrounding body portion 13 before entering the plug 12 and thus leading to the space 19. The functioning of the nozzle is the same as that described with reference to Fig. 1.
The nozzle of Fig. 5 is for use with aerosol formulations where the propellant gas is dissolved or otherwise dispersed within the liquid product or for situations in which there is no propellant gas and the product is itself compressed. In this case there is no need for a separate gas inlet duct. The combined gas/product stream, or the product stream alone, passes along liquid inlet duct 22, annular duct 26 and axial ducts 25 to the space 19 and thus out through discharge opening 18 where the liquid product is atomised.
Fig. 6 shows a nozzle used for aerosol formulations. The cap 19 is connected to the plug 12 by a screw thread 27. By rotation of the cap 17 the thickness of space 19 may be varied and when the cap 17 is screwed in completely the discharge outlet 21 is closed by engagement against the convex surface 14 of plug 12.

Claims

1. A nozzle for dispensing liquids in an atomised form under pressure, comprising a body having a convex face; a cap member overlying the convex face of the body and having a concave face lying in close proximity with the convex face and defining therebetween an enclosed space, a discharge outlet extending through the cap member distal to an edge of the said space, and a liquid inlet duct opening into the said space proximal to an edge thereof.

2. A nozzle as claimed in claim 1 in which a gas inlet duct is provided in the body which duct opens into the enclosed space.

3. A nozzle as claimed in claim 2 in which the gas inlet opens into the enclosed space through the convex face substantially in axial alignment with the discharge outlet.

4. A nozzle as claimed in claim 2 or claim 3 in which the gas inlet duct includes a plenum chamber immediately prior to its entry into the enclosed space.

5. A nozzle as claimed in any one of claims l to 4 in which the convex face of the body is curved in two planes.

6. A nozzle as claimed in claim 5 in which the convex face is hemispherical.

7. A nozzle as claimed in any one of claims 1 to 6 in which the cap member is affixed to the body such that the thickness of the enclosed space between the convex face of the body and the concave face of the cap member may be varied.

8. A nozzle as claimed in any one of claims 1 to 7 in which the enclosed space between the convex face of the body and the concave space of the cap member is thinner adjacent the discharge outlet than in areas around the periphery of the space.

9. A nozzle as claimed in claim 7 in which the faces of the cap member and of the body can be relatively moved into contact to prevent the discharge of the liquid through the nozzle.

10. A nozzle as claimed in any one of claims 1 to 9 in which there are a plurality of liquid inlet ducts opening into the enclosed space, the inlet ducts entering the enclosed space at points spaced around the periphery thereof.