WO2010098681A1

WO2010098681A1 - An improved nozzle for a fluid dispenser

Info

Publication number: WO2010098681A1
Application number: PCT/NZ2010/000033
Authority: WO
Inventors: Paul Fleming Buckley; David Andrew Trow
Original assignee: Forlong & Maisey Limited T/A Instrument Supplies
Priority date: 2009-02-26
Filing date: 2010-02-25
Publication date: 2010-09-02

Abstract

The invention relates to a nozzle for a fluid dispenser, wherein the nozzle includes a fluid outlet, and a base for the fluid outlet, and a valve which seals the fluid outlet until biased open, and a fluid distribution surface, and a nozzle tip, characterised in that the fluid distribution surface includes a plurality of discontinuities between the base of the fluid outlet and the nozzle tip, and wherein the valve is placed at the base. A method of use is also claimed.

Description

AN IMPROVED NOZZLE FOR A FLUID DISPENSER

TECHNICAL FIELD

The present invention relates to an improved nozzle for a fluid dispenser.

The invention has particular application for an improved nozzle for a fluid dispenser for use in animal husbandry.

However, persons skilled in the art will appreciate that the improved nozzle may be used in any industry which requires delivery of fluids to a surface.

BACKGROUND ART

Pour-on applicators are widely used in animal husbandry and the animal agricultural sector, so that fluids, such as pour-on, may be applied to commercially valuable animals, such as dairy or beef cattle, sheep, deer, horses and the like.

Pour-on, which is also known as "back liner" in some countries, is a medicament which is applied along the back of the animal to be treated. Pour-on is usually used to treat lice or other external parasites which may cause skin or other health related issues, as well as some internal parasites.

A pour-on applicator is provided with a fluid supply, and handle which acts as a lever to actuate a piston. Once actuated, the piston moves through the barrel of the applicator to force a specific dosage amount of fluid past a sprung outlet valve and out the nozzle of the applicator. The outlet valve seals the applicator so that there is no undesired flow of fluid.

Once the fluid has been delivered, the piston returns to a rest position when the handle is released, to allow automatic re-filling of the applicator. In order to pass fluid through the nozzle of the applicator, it is necessary to apply sufficient force to the piston as it moves through the barrel of the applicator. The handle of the applicator has a spring, the biasing force of which must be overcome by the user when actuating the applicator.

The user must also overcome the outlet valve of the applicator. It can be appreciated that the repeated actuation of the handle of a pour-on applicator can lead quickly to user fatigue, especially if large numbers of animals need to be treated.

Another factor which contributes to the force applied to the piston is the construction of the nozzle. The nozzle of some conventional pour-on applicators are similar to a shower head or "rose" which has a number of small apertures through which fluid must pass.

When the handle is actuated, this can lead to a slowing down in fluid delivery as more fluid enters the nozzle from the barrel of the applicator than is possible to exit the nozzle via the small apertures at a consistent rate. To compensate, the user of the applicator needs to apply even more force to the handle, and in turn the piston, to maintain a constant flow of liquid.

A further problem with conventional applicators is the dispersal of the fluid being delivered. Typically, due to the architecture of a conventional nozzle, the fluid flow as it exits the nozzle tends to be relatively concentrated. This is usually due to the pressure that is being applied to the fluid by the driving piston.

Furthermore, although there may be an initial individual flow of fluid from each aperture of the nozzle, the inherent surface tension of the fluid stream can cause individual fluid streams to merge together to create a more concentrated stream of fluid.

Another issue with conventional applicators is the formation of an air bubble within the barrel of the applicator. This can cause problems when delivering fluid as the air bubble may prevents a consistent fluid stream from forming. The air bubble can also adversely affect the accuracy of the dose delivered to the animal being treated.

Although careful manipulation of the applicator can reduce the impact of an air bubble on the fluid stream, this is relatively time consuming to achieve particularly when large numbers of animals need to be treated.

When an air bubble forms, the applicator needs to be orientated to a substantially vertical position. This causes the air bubble to rise, towards the nozzle. Actuation of the piston will move the air bubble out the nozzle first, ahead of the fluid. Without this manipulation of the applicator, it can be difficult to eliminate an air bubble without some loss of the fluid being delivered.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention there is provided a nozzle for a fluid dispenser, wherein the nozzle includes;

a fluid outlet, and

a base for the fluid outlet, and

a valve which seals the fluid outlet until biased open, and

a fluid distribution surface, and

a nozzle tip,

characterised in that

the fluid distribution surface includes a plurality of discontinuities between the base of the fluid outlet and the nozzle tip, and wherein the valve is placed at the base.

According to one aspect of the present invention, there is provided a fluid dispenser, wherein the dispenser includes a nozzle substantially as described above. According to another aspect of the present invention, there is provided a method of operating a fluid dispenser, the dispenser including;

a piston, and

a reservoir for fluid to be delivered, and

a nozzle through which fluid exits the dispenser, wherein the nozzle includes a fluid outlet, a base for the fluid outlet, a valve which engages with the fluid outlet, a fluid distribution surface, and a nozzle tip,

the method characterised by the steps of

(a) filling the reservoir with the fluid to be delivered, and

(b) moving the piston through the reservoir such that the fluid is displaced from the reservoir via the nozzle, wherein the nozzle is characterised in that the fluid distribution surface includes a plurality of discontinuities between the base of the fluid outlet and the nozzle tip, and wherein the valve is placed at the base.

The invention broadly relates to a nozzle or outlet for a fluid dispenser. The fluid dispenser may be a syringe or a drench gun but preferably is a pour-on applicator, which is used to deliver fluid medicaments to animals as a spray or mist.

However, a person skilled in the art will appreciate that the present invention may be used with fluid dispensers used in other industries such as the medical sciences, the food, hospitality, or horticultural industries all of which may require application of fluids to surfaces as a spray or mist.

Reference shall now be made to the fluid dispenser as being a pour-on applicator. A pour-on applicator typically includes a barrel, a piston, a handle linked to the piston such that the piston moves through the barrel upon actuation of the handle, and a nozzle to direct fluid as it exits the barrel.

The nozzle may simply be an extension from one end of the barrel of an applicator. Alternatively, the nozzle is a separate tube which engages with a fitting at one end of the barrel.

The nozzle should be understood to have two ends, a first end which engages with the barrel of the applicator (alternatively, the nozzle may engage with an extension or other fitting arising from the barrel), and an open second end, the nozzle tip, from which fluid exits the nozzle.

Open should be understood to mean that there are no obstructions, such as a cap or rose, at this part of the nozzle which may inhibit fluid flow from the nozzle tip.

At the second end, the nozzle is provided with a fluid outlet. The fluid outlet may be one or more apertures through which fluid must pass.

In preferred embodiments of the present invention, the fluid outlet is situated at least part way down the tip of the nozzle.

In preferred embodiments of the present invention, the fluid outlet has a base. A base should be understood to mean a surface which surrounds the aperture or apertures forming the fluid outlet.

The nozzle of the pour-on applicator includes a fluid distribution surface. This should be understood to mean a surface which distributes fluid as it exits the nozzle.

For example, the fluid distribution surface may be simply a disc with apertures passing from one side of the disc to the other. This disc is placed over or is inserted into the end of the nozzle.

In preferred embodiments of the present invention, the fluid distribution surface includes a plurality of discontinuities such that the fluid distribution surface is discontinuous.

A discontinuous fluid distribution surface should be understood to mean a surface which is provided with a broken or disrupted surface to allow dispersal of the fluid in a spray or mist as it exits the nozzle.

For example, the discontinuities may be in the form of a plurality of raised domes or bumps which are configured into the surface of the interior of the nozzle, between the fluid outlet base and the tip of the nozzle. As fluid exits the fluid outlet, the fluid passes over the domes, breaking up the fluid stream as it exits the nozzle. If the fluid stream is sufficiently broken up or dispersed, this will prevent the fluid from combining into a single or a few individual streams when it exits the nozzle.

Preferably, the interior of the nozzle tube between the nozzle tip and the base for the fluid outlet is configured with a plurality of recessed channels. It should be understood that these recessed channels form part of the fluid distribution surface.

In some embodiments of the present invention, the channels may only run from the nozzle tip to a point part way down the interior of the nozzle, rather than running to the base of the fluid outlet.

Other methods of forming a discontinuous fluid distribution surface will be readily apparent to a person skilled in the art. However, it is envisaged that the present invention may also be used in nozzles without a discontinuous surface.

In preferred embodiments in the present invention, the fluid distribution surface includes a fluid outlet in the form of at least one aperture with a valve situated above the fluid outlet.

Preferably, the valve is an elastomeric valve. This should be understood to mean that the valve is made from an elastomer, which has elastic properties. In particular, the valve can be temporarily deformed and is able return to its normal state without the aid of a spring or other similar mechanical means.

Preferably, the valve is an umbrella valve. An umbrella valve is a valve which, in a side view, resembles an umbrella. The outer perimeter of the underside of the canopy of the umbrella valve engages with the surface which is to be sealed. The stem of the umbrella is inserted into a recess which holds the valve in position.

In some embodiments of the present invention, the valve may be a flat disc secured at its centre to the fluid outlet.

In these embodiments of the invention, the perimeter of the disc biases against the raised surface surrounding the fluid outlet such that the outlet is sealed. The disc, when sealing the fluid outlet, takes on a slight cone-like shape in cross-section, the dome of the cone facing the fluid outlet.

Preferably, the fluid outlet is configured with a suitable recess in which the stem of the umbrella valve engages.

In preferred embodiments of the present invention, the fluid outlet is constructed with a central aperture into which the stem of the umbrella valve is inserted, surrounded by a plurality of secondary apertures through which fluid passes from the barrel and out the nozzle.

It will be appreciated that the secondary apertures form the fluid outlet.

It is also important to appreciate that it is the material from which the umbrella valve, or more specifically the canopy of the umbrella valve, is constructed which provides the biasing force which keeps the valve canopy in a sealing position. If the fluid pressure under the canopy exceeds the pressure above the canopy by more than a predetermined amount, then the edge of the canopy lifts, allowing fluid to flow.

Preferably, the umbrella valve is constructed from a flexible elastomeric material, such as a nitrile rubber or latex. In preferred embodiments of the present invention, the umbrella valve is constructed from silicone rubber. It has been found that silicone rubbers experience less variation in flexibility at lower temperatures.

The use of an umbrella valve in the nozzle of a fluid applicator is particularly advantageous as due to the absence of a spring, little pressure is required to overcome the biasing force of the valve.

However, the umbrella valve maintains a sufficiently good seal that it can function as the outlet valve of the applicator. No additional valve is required to function as the outlet valve for the applicator.

However, in some embodiments of the present invention, the valve may be biased by a spring.

In this embodiment of the invention, once the fluid pressure exceeds the biasing force of the spring, the valve moves away from the outlet thus forming a gap between through which fluid can pass. However, the user must still apply sufficient force to the piston to ensure the biasing force of the spring can be overcome.

Persons skilled in the art will appreciate that there may be other valves in the nozzle, which may or may not be umbrella valves.

In use, as the fluid meets the fluid outlet, which is sealed by the umbrella valve, the increase in pressure biases the valve open. The fluid is directed along the interior surface of the nozzle towards the nozzle tip.

In some embodiments of the present invention the fluid outlet may be configured such that the outlet is raised on a dome or similar structure within the nozzle, such that a recess is formed between the walls of the interior of the nozzle and the fluid outlet. Configuring the fluid outlet in this manner can assist in the directing of the fluid as it exits the fluid outlet.

When the fluid meets the sides of the interior of the nozzle, it enters the channels which lead towards the nozzle tip. The fluid is then directed in streams out of the nozzle.

In preferred embodiments of the present invention, at least a portion of the nozzle which forms the nozzle tip terminates in a cone-like configuration. Thus, it will be appreciated by having the fluid following the internal lines of the nozzle, a cone like spray or fluid distribution may be formed. This allows better fluid dispersal and coverage, with a minimal amount of pressure required to create this effect.

There may be subtle variations in the cone-like configuration of the nozzle tip. For example, the nozzle tip may be configured with a cone that provides an oval spray pattern. This may be achieved by constructing the cone with an elliptical cross- section. Persons skilled in the art will appreciate that by altering the shape of the nozzle tip, a variety of spray patterns may be formed.

Persons skilled in the art will also appreciate that the greater the angle of the sides of the nozzle tip away from the nozzle axis, the wider and more divergent the resulting fluid spray.

According to another aspect of the present invention there is provided a fluid dispenser, wherein the fluid dispenser includes

a barrel for a fluid, wherein in normal operation, the barrel has an upper most portion and a lower most portion, and

a nozzle for the fluid to exit the barrel,

characterised in that

in normal operating positions, the nozzle is positioned substantially uppermost with respect to the barrel.

According to yet another aspect of the present invention there is provided a barrel for a fluid dispenser, wherein in normal operation, the barrel has an upper most portion and a lower most portion, the barrel including

a nozzle,

characterised in that

in normal operating positions, the nozzle is positioned substantially upper most with respect to the barrel.

According to yet another aspect of the present invention there is provided a method of operating a fluid dispenser, the fluid dispenser including a barrel for a fluid, wherein in normal operation, the barrel has an upper most portion and a lower most portion, and

a piston configured to move through the barrel, and

a nozzle for the fluid to exit the barrel,

the method characterised by the steps of

(a) filling the barrel with the fluid to be delivered, and

(b) moving the piston through the barrel such that the fluid is displaced from the barrel via the nozzle, wherein the nozzle is characterised in that in normal operating positions, the nozzle is positioned substantially upper most with respect to the barrel.

The invention broadly relates to a nozzle or outlet for a fluid dispenser.

Preferably, the fluid dispenser is a drench gun or pour-on applicator, which is used to deliver medicaments to animals.

However, a person skilled in the art will appreciate that the present invention may be used with fluid dispensers used in other industries such as the medical sciences, the hospitality industry, or horticultural industry, all of which may require application of fluids to surfaces.

Reference shall now be made to the fluid dispenser as being a pour-on applicator.

In conventional pour-on applicators, the barrel includes at one end an elongated nozzle through which fluid passes as it moves through the barrel and out the nozzle tip. In preferred embodiments of the present invention, the barrel has substantially parallel sides. One side of the barrel may be thought of as the lower most portion. This is the portion regarded as the underside of the barrel which faces the ground when the applicator is in a normal operating position.

The upper most portion of the barrel is the side of the barrel which faces the user or the sky when the applicator is in a normal operating position.

In preferred embodiments of the present invention, the barrel may be provided with a barrel extension to which the nozzle is fitted.

In this embodiment of the invention, the upper most portion of the barrel extension and the upper most portion of the barrel are substantially continuous or inline.

In alternative embodiments of the present invention, the barrel extension may be at an angle relative to the barrel. In these embodiments of the invention, the junction (where the barrel extension meets the barrel) between the barrel extension and the barrel is at the upper most portion of the barrel.

Throughout the remainder of the specification it should be understood that when referring to a barrel, this is meant to include a barrel provided with a barrel extension.

However, this should not been seen as limiting, as it is foreseen that some barrels may not be provided with a barrel extension, and the point of junction (where the nozzle meets the barrel) between the nozzle and the barrel is at the upper most portion of the barrel.

It should be understood that a normal operating position for the applicator is to mean a substantially horizontal orientation, that is to say, the barrel and nozzle are substantially parallel to the ground when in a normal operating position.

However, persons skilled in the art will appreciate that there may be some variance in the orientation of the applicator depending on the user's preference when operating the applicator.

It should be understood that the nozzle is an elongate tube with substantially parallel sides.

However, in some embodiments of the present invention, the nozzle may have tapering sides although this does not alter the sustenance of the present invention. In other embodiments of the present invention, portions of the nozzle may be at an angle relative to another portion of the nozzle.

The upper most portion of the nozzle should be understood to mean the portion of the nozzle which faces the user or the sky when the applicator is in a substantially horizontal orientation.

In preferred embodiments of the present invention, the upper most portion of the barrel and the upper most portion of the nozzle is substantially continuous or inline.

However, persons skilled in the art will appreciate that this is not meant to be limiting.

It is envisaged that in some embodiments of the present invention, the placement of the nozzle may not be inline with the upper most portion of the barrel, but will still be positioned substantially upwards of a line drawn through the centre of the barrel when in a normal operating position.

Persons skilled in the art will also appreciate that some users of the present invention, depending on their requirements, may wish to have the nozzle situated such that the lower side of the nozzle and the lower most portion of the barrel are substantially continuous.

In some embodiments of the present invention, at least a portion of the nozzle may be angled away or displaced relative to the line of the barrel. However, in this embodiment of the invention, the junction (where the nozzle meets the barrel) between the nozzle and the barrel is substantially continuous with the line of the upper most portion of the barrel.

In use, as the piston moves through the barrel, any air bubbles which are present naturally rise and collect at the upper most portion of the barrel. As the piston continues to move the fluid towards the nozzle, the air bubbles are forced towards the nozzle.

Alternatively, the user of the applicator merely needs to angle the applicator slightly upwards in order to allow the air bubbles to move towards the nozzle of the applicator.

It can be appreciated that the position of the nozzle relative to the barrel makes it considerably easier for the collected air bubbles to pass out the nozzle without impacting on the stream of fluid as it exits the applicator.

It will be appreciated that the present invention has a number of advantages.

• Improved dispensing of fluid with minimal application of pressure, but without compromising the ability of the outlet valve to prevent inadvertent passing of fluid from the applicator;

• Improved fluid dispersal from the fluid dispenser;

• Greater coverage of an area to be treated with a fluid; • Improved ability to eliminate air bubbles which may be present in the fluid being delivered.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a perspective view of the improved nozzle for a fluid dispenser; and

Figure 2 shows a side view of the umbrella valve; and

Figure 3 shows a side view of the applicator.

BEST MODES FOR CARRYING OUT THE INVENTION

The improved nozzle (generally indicated by arrow 1) which is attached to an applicator barrel (2) is illustrated in Figure 1.

The nozzle (1) includes a fluid outlet (not shown) and a valve (3), in the form of an umbrella valve (3), for the fluid outlet (not shown).

The interior surface (4) of the nozzle (1) includes a number of channels or recessed grooves (5) which lead from the fluid outlet (not shown) to the tip (6) of the nozzle (1).

The fluid (not shown) exits the fluid outlet (not shown), and is directed by the valve (3) towards the channels (5) running along the interior (4) of the nozzle (1) towards the nozzle tip (6).

This allows fluid (not shown) to move along the channels (5) and exit the nozzle (1) in a dispersed cone-like pattern (not shown). A greater area is able to be covered by the resulting fluid spray.

Figure 2 illustrates the umbrella valve (3) in a side view. The umbrella valve (3) includes a canopy (7), the perimeter (8) of which is intended to engage with the fluid outlet (not shown) of the nozzle (not shown), such that the fluid outlet (not shown) is sealed. When installed into the nozzle (not shown), the perimeter (8) of the valve (3) is slightly distended against the valve seat (not shown) to tension the valve (3).

The umbrella valve (3) also includes a stem (9), which is inserted into an appropriately shaped recess (not shown) in the fluid outlet (not shown). The canopy (7) of the umbrella valve (3) is distended when the pressure of fluid (not shown) on the underside (10) of the canopy (7) exceeds the atmospheric pressure and the tension acting upon the upper side (11) of the canopy (7).

In Figure 3, the position of the nozzle (1) relative to the barrel (2) of the applicator (12) can be appreciated.

The upper most portion (13) of the nozzle (1) is substantially in line with the upper most portion (14) of the barrel (2). In the illustrated embodiment of the invention, the barrel (2) is provided with an extension (15) to which the nozzle (1) is fitted.

Air bubbles (not shown), being less dense than the fluid (not shown), naturally rise upwards. Therefore, when the applicator (12) is used in a generally horizontal orientation, air bubbles (not shown) will gravitate towards the upper most portion (14) of the barrel (2). As fluid (not shown) is forced along the barrel by the piston (not shown) of the applicator (12), the air bubbles (not shown) are easily moved into the nozzle (1) such that the air bubbles (not shown) can exit the nozzle (1) first, without impacting on the flow of fluid (not shown) exiting the nozzle (1).

Alternatively, the user can orientate the applicator (12) such that the applicator (12) is angled upwards. This will also cause movement of any air bubbles (not shown) towards the nozzle (1).

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

Claims

WHAT I/WE CLAIM IS:

1. A nozzle for a fluid dispenser, wherein the nozzle includes;

a fluid outlet, and

a base for the fluid outlet, and

a valve which seals the fluid outlet until biased open, and

a fluid distribution surface, and

a nozzle tip,

characterised in that

2. A nozzle as claimed in claim 1, wherein the fluid outlet is situated in the interior of the nozzle.

3. A nozzle as claimed in claim 1 or claim 2 wherein the fluid outlet is situated at least part way down the tip of the nozzle.

4. A nozzle as claimed in any one of claims 1 to 3 wherein the fluid outlet is raised on a dome or similar structure within the nozzle, such that a recess is formed between the walls of the interior of the nozzle and the fluid outlet.

5. A nozzle as claimed in any one of claims 1 to 4 wherein the valve is an umbrella valve, the umbrella valve including a stem and a canopy with an outer perimeter.

6. A nozzle as claimed in claim 5 wherein the canopy of the umbrella valve is situated above the fluid outlet.

7. A nozzle as claimed in either claim 5 or claim 6 wherein the outer perimeter of the canopy is configured to engage the base of the fluid outlet.

8. A nozzle as claimed in claim 7 wherein the surface to be sealed includes the fluid outlet.

9. A nozzle as claimed in any one of claims 5 to 8 wherein the fluid outlet is configured with a suitable recess in which the stem of the umbrella valve engages.

10. A nozzle as claimed in claim 9 wherein the recess is surrounded by a plurality of secondary apertures.

11. A nozzle as claimed in claim 10 wherein the secondary apertures is the fluid outlet.

12. A nozzle as claimed in any one of claims 1 to 3 wherein the valve is a flat disc secured at its centre to the fluid outlet.

13. A nozzle as claimed in claim 12 wherein the portion of the base of the fluid outlet surrounding the fluid outlet is raised.

14. A nozzle as claimed in claim 13 wherein the disc is configured to bias against the raised portion of the base of the fluid outlet such that the outlet is sealed.

15. A nozzle as claimed in any one of claims 1 to 14 wherein the valve is constructed from a flexible elastomeric material, such as a nitrile rubber.

16. A nozzle as claimed in any one of claims 1 to 14 wherein the valve is constructed from silicone rubber.

17. A nozzle as claimed in any one of claims 1 to 16 wherein the discontinuities are a plurality of raised domes or bumps configured into the surface of the interior of the nozzle.

18. A nozzle as claimed in any one of claims 1 to 16 wherein the discontinuities are a plurality of recessed channels configured into the surface of the interior of the nozzle tube.

19. A nozzle as claimed in claim 18 wherein the channels run from the nozzle tip to a point part way down the interior of the nozzle.

20. A nozzle as claimed in claim 18 wherein the channels run between the nozzle tip and the base for the fluid outlet

21. A nozzle as claimed in any one of claims 1 to 20 wherein the nozzle tip terminates in a cone-like configuration.

22. A nozzle as claimed in any one of claims 1 to 20 wherein the nozzle tip is configured with an elliptical cross-section.

23. A fluid dispenser, wherein the dispenser includes a nozzle as claimed in any one of claims 1 to 22.

24. A fluid dispenser as claimed in claim 23 wherein the fluid dispenser is a pour-on applicator.

25. A method of operating a fluid dispenser, the dispenser including; a piston, and

a reservoir for fluid to be delivered, and

a nozzle through which fluid exits the dispenser, wherein the nozzle includes a fluid outlet, a base for the fluid outlet, a valve which seals the fluid outlet until biased open, a fluid distribution surface, and a nozzle tip,

the method characterised by the steps of:

(a) filling the reservoir with the fluid to be delivered, and

(b) moving the piston through the reservoir such that the fluid pressure biases open the valve, displacing the fluid from the reservoir via the fluid outlet of the nozzle, wherein the nozzle is characterised in that the fluid distribution surface includes a plurality of discontinuities between the base of the fluid outlet and the nozzle tip, and wherein the valve is placed at the base.

26. A nozzle for a fluid dispenser substantially as herein described and with reference to the accompanying drawings.

27. A fluid dispenser substantially as herein described and with reference to the accompanying drawings.

28. A method of operating a fluid dispenser substantially as herein described and with reference to the accompanying drawings.