Patent Description:
Fluid dispensers of various types are known, such as for dispensing gel, foam or liquid soaps and alcohol sanitizers. The fluid dispensers may have an integral pump or a pump as part of a disposable and replaceable fluid container. The pump may be actuated to dispense fluid from a fluid container within the dispenser. Such pumps may be manually or automatically actuated to dispense the fluid by a pressing force or by a sensor sensing the presence of a hand.

Commercial liquid dispensers frequently use inverted disposable containers that can be placed in more permanent, dispensing devices. The dispensers may be affixed to walls of washrooms or the like. The devices are often located in washrooms or at the entrances to public buildings. Having the pump being integral to the disposable container as part of a disposable fluid dispensing package is desirable as it makes refilling the dispenser more convenient. It nevertheless requires the pump to be simple and cheap with a minimum of disposable parts.

Fluid dispensers are generally affixed to a wall or support structure, providing greater freedom in the direction and amount of force that is required for actuation. By the device being supported by an additional structure, they do not require two points of contact by the user for actuation. Thereby the points of contact by the user are reduced to <NUM>, or even zero when such devices use sensors. Sensor activation may identify the presence of a user's hand beneath the outlet to activate the pump. This avoids user contact with the device and the associated cross-contamination. It also prevents incorrect operation that can lead to damage and premature ageing of the dispensing mechanism. Alternatively, the user may manually actuate the pump by a pressing force imparted by a hand that may be subsequently washed with the dispensed fluid thereby reducing contamination during operation.

Various pumps are known that are suitable for the purpose of fluid dispensing. For example, in <CIT>, a pump is shown based on a plastomer spring and pump chamber. The pump is actuated by compressing the pump chamber between two concentric sleeves. The pump is received within a dispenser that interacts with the sleeves to actuate the pump. The pump has an outlet in the form of an orifice that delivers the product to a user. For certain viscous materials, such as soaps, the orifice provides adequate delivery.

A problem associated with pumps existing in the art is that the product is not always dispensed in a single defined direction. Caking of the nozzle may occur with certain products, leading to partial blockage and delivery in undesired directions. This is particular the case for alcohol sanitizers and alcogels, having a volatile fraction that may evaporate. Spray from the orifice or nozzle can accumulate on adjacent surfaces of the dispenser. The user may also be affected by spray unexpectedly landing on their clothing or other body parts including in the eyes. This can cause increased service time in an area where the pump is installed, e.g. washroom area, if the pump spray must be cleaned off other surfaces.

Attempts have been made to improve the delivery by providing a nozzle having a greater axial extent in order to ensure a more focussed delivery. Nevertheless, increasing the length of the nozzle with respect to the neighbouring parts of the dispenser can increase the exposure to spray in a lateral direction. An additional factor that needs to be taken into account for pumps of the type having a compressible or collapsible pump chamber is that the outlet orifice or nozzle must be securely retained during actuation. Any tendency of the outlet portion to twist or deviate during distortion of the pumping chamber could exacerbate problems of spaying and inaccurate delivery. This is particularly important in the case of plastomer based pumps, where the force required for delivery may be relatively high.

It would be desirable to have a pump assembly that provides for focussed delivery of a sanitizing fluid or the like and that reduces the incidence of stray droplets. The pump assembly should advantageously be hygienic, simple to manufacture, maintain and assemble and/or economical to produce. It should also preferably be robust for commercial usage.

The invention relates to a pump assembly and method according to the accompanying independent and dependent claims. Combinations of features from the dependent claims and independent claims may be combined with features as appropriate and not merely as explicitly set out in the claims.

In the invention, a pump assembly is disclosed for dispensing a fluid from a fluid container. The pump assembly is of the type comprising an upper sleeve and a lower sleeve, slidingly engaged together and a pump having an inlet end, an outlet end and a pump chamber therebetween, the pump being retained within the sleeves with the inlet end located at an upper end of the upper sleeve and the outlet end located at a lower end of the lower sleeve, whereby movement of the lower sleeve towards the upper sleeve causes the pump chamber to reduce in volume. The outlet end of the pump has a shoulder between a first diameter portion and an outlet nozzle, the outlet nozzle extending downwardly from the shoulder and having a second diameter smaller than the first diameter portion. The lower end of the lower sleeve comprises a shield, extending from a lowermost rim upwards and inwards to terminate at an orifice, the orifice being larger than the second diameter but smaller than the first diameter portion and the shield forming a domed continuous surface. The shoulder thus supports against a lip of the orifice and the outlet nozzle extends through the orifice to terminate at a dispersion location within the shield at a distance L from the orifice. Further, the domed continuous surface has a height of between <NUM> and <NUM> between the rim and the orifice.

The nozzle ensures a focussed delivery of the fluid. In the present context, fluid is intended to encompass, liquids, gels, dispersions, emulsions, foams and any other form of composition that may be delivered by pumps of this type. Nevertheless, the further that the nozzle extends from the lower sleeve, the greater is its exposure and the more likely that droplets may stray in undesired directions. According to the claimed embodiment, by providing the shield around the nozzle, lateral spraying can be prevented.

The orifice marks the point at which the lower end of the lower sleeve engages with the outlet end of the pump. This is the point at which force is transmitted to the pump in order to cause collapse of the pumping chamber. By providing a domed surface to the shield, force can better be transmitted through the lower shield to the outlet end of the pump. Furthermore, the continuous nature of the surface ensures that any spray is kept within the shield and can be easily cleaned. In this context, continuous surface means that it does not have any openings through which liquid or droplets might penetrate. Preferably, the domed surface is continuous and hermetic from the rim to the orifice.

The shield may have any domed shape that ensures good force transmission between the rim and the point of engagement with the shoulder of the outlet end of the pump. It may be hemispherical or part spherical, vaulted, arched or part ovoid. In an embodiment, it may be described as paraboloid. The skilled person will understand that this does not mean that it need have a mathematically perfect parabolic shape but merely that it is smooth and structurally able to transmit the required force with a minimum of structural thickness. In certain embodiments, the shield may have a wall thickness of between <NUM> and <NUM>, preferably between <NUM> and <NUM> and optionally no thicker than the wall thickness of the lower sleeve. Providing the shield to have a similar thickness to the remainder of the lower sleeve is advantageous in manufacturing, since parts having a homogenous thickness distribution are more stable to manufacture using certain techniques such as injection moulding and the like.

In an embodiment, the shield has a diameter at the rim in the range <NUM> to <NUM>, optionally between <NUM> and <NUM>. In the invention, the domed continuous surface has a height of between <NUM> and <NUM> between the rim and the orifice, optionally between <NUM> and <NUM>. As will be understood and as described further below, the relative dimensions of the shield will determine the manner in which it limits spray in directions other than the desired direction.

The effectiveness of the shield will also depend on the position of the dispersion location, which is also dependent upon the length of the nozzle. In one embodiment, the nozzle has a length of between <NUM> and <NUM> as measured from the shoulder. This may preferably be between <NUM> and <NUM>. The length of the nozzle is given here as the external dimension as measured from the connection to the shoulder. It will be understood that the nozzle will protrude a lesser distance towards the dispersion location, since the shoulder rests against the lip of the orifice at a rear side of the shield. It will also be understood that for the fluid exiting the nozzle, the effective nozzle length will depend upon the length of the internal channel, which may be different to the external length of the nozzle. The distance L may be in the range from <NUM> to <NUM>, optionally between <NUM> and <NUM>. Seen in a different perspective, the nozzle is recessed within the shield and set back from the lowermost rim. The dispersion location may be set back a distance of from <NUM> to <NUM> from the rim, preferably from <NUM> to <NUM>.

In an embodiment, the orifice may have a diameter in the range from <NUM> to <NUM>, optionally between <NUM> and <NUM>. Here too, the size of the orifice will depend upon the outer diameter of the nozzle, particularly at its base. It will also be understood that the diameter of the nozzle may vary along its length, in particular, it may taper towards the dispersion location. The retention of the nozzle within the orifice will be important in ensuring a stable retention of the pump, especially during compression. The shoulder at the outlet end of the pump may be smooth but may also be provided with a step or seat to better locate in the orifice. In an embodiment, the lower sleeve engages with the pump only at the lip of the orifice and does not extend towards the inlet end of the pump or otherwise surround the outlet end of the pump.

As a result of the above defined geometrical relations of the shield and nozzle, a limited spray angle may be achieved. In the present context, the spray angle may be defined as the angle between a line from a centre of the dispersion location to the rim and an axis of the nozzle. This spray angle is preferably between <NUM> degrees and <NUM> degrees, preferably between <NUM> degrees and <NUM> degrees. The skilled person will understand that this is defined as around half of the overall angle over which spray can be encountered. The actual overall angle will be slightly greater than twice the spray angle, since the dispersion location has a finite diameter and droplets can deflect from an opposite edge of the dispersion location and even from caked product extending beyond the nozzle. It will also be understood that it is not the purpose of the disclosure to provide a uniform delivery within this conical boundary, which merely represents the maximum extent to which droplets can stray.

Reference here is given to the axis of the nozzle. In general, this will also be the axis of the pump and also of the upper and lower sleeves, all of which are concentric. It is however not a requirement that this is the case and also not a requirement that the shield is concentric or fully symmetrical with other items. The purpose of the shield is to transmit force to the pump and avoid unwanted spray in certain directions. The shield may therefore orient more in one direction than in another direction and the lowermost rim need not necessarily be perpendicular to the respective axes of the pump and the nozzle.

According to an embodiment the lower sleeve is slideably retained together with the upper sleeve by interacting guide elements. The guide may comprise a snap-on resilient connecting part such as a tongue and groove arrangement or a detent, engageable with a channel. Such a connection allows for simple assembly of the sleeves, while retaining them in concentric arrangement, preventing the lower sleeve from disengaging under gravity or other forces occurring during its lifetime.

In an embodiment, the lower sleeve may also be rotatable with respect to the upper sleeve in the uncompressed, extended position. This may allow the lower sleeve to be rotated to a locked position in which the pump cannot be compressed, thereby preventing accidental actuation of the pump. This may be used during initial storage and transport of the pump prior to use.

According to an embodiment the sleeves are made from one or more plastic materials of the following list: PP (polypropylene), PET (polyethylene terephthalate), PE (polyethylene), PVC (polyvinyl chloride), PA (polyamide), PC (polycarbonate), POM (polyoxymethylene), ABS (acrylonitrile butadiene styrene) or PS (polystyrene). A preferred material for both sleeves is HDPE although it will be understood that they do not need to be both manufactured of the same material.

In a preferred embodiment, the lower sleeve surrounds the upper sleeve. This is the configuration corresponding to presently used pumps of this type and allows pumps according to the present disclosure to be used in existing dispensers. In such case the lower, outer sleeve may be provided with a flange at its upper end for actuation in an upwards direction. The skilled person will understand that this configuration, as further detailed below, can be easily reversed with the upper sleeve outermost.

In a further embodiment, a diameter of the lower sleeve is greater than a diameter of the rim of the shield, preferably between <NUM> and <NUM>, optionally between <NUM> and <NUM>. There is thus a narrowing of the lower sleeve, which may taper towards the rim. In this context, the diameter of the lower sleeve is used to refer to the constant diameter portion of the sleeve which is in sliding relation to the upper sleeve. Clearly, there may be parts of this element that extend further outwardly, such as the actuating flange mentioned above.

According to an embodiment the lower sleeve has a length in the range <NUM>-<NUM>, optionally between <NUM> and <NUM>. The thickness of the lower sleeve may be in the range <NUM> to <NUM>, optionally around <NUM> to <NUM>.

In a particular embodiment, the pump comprises a plastomer spring located within the pump chamber. Such pumps have been found extremely versatile in terms of minimising production costs by minimising the number of components. The pump chamber may also be collapsible, preferably of plastomer material. The pump chamber and spring may together provide inlet and outlet valves, whereby a pump is formed of just two pump components.

According to one embodiment the lower sleeve is a monolithic structure, in other words, the shield and the lower sleeve are a single element. Preferably this is a single injection moulded component. The upper sleeve may also be a single component, whereby the whole pump may be formed of just four elements, reducing production complexity and assembly operations.

The disclosure also relates to a disposable fluid dispensing package, comprising a pump assembly as described above and hereinafter, sealingly connected to a collapsible product container. The container may be permanently connected to the inlet end of the pump, e.g. by gluing or welding. Alternatively, it may be releasably connected e.g. by a snap fit, screw or bayonet connection.

The disposable fluid dispensing package may comprise a quantity of a liquid or gel product contained within the collapsible product container. In an embodiment, the package may be delivered to a user, filled and sealed and ready to be inserted into a suitable dispenser, with the pump assembly already attached. The pump assembly may itself form part of the seal or closure that prevents egress of the product prior to installation in the dispenser. In an embodiment, this seal is provided by the inlet and/or outlet valves of the pump. In this case there may be no requirement of any other removable or frangible seal, leading to a further reduction in components and potential garbage. Locking of the sleeves to prevent movement may ensure that the inlet and outlet valves cannot leak.

The invention also teaches a method of preventing emission of stray droplets in a fluid dispenser, the method comprising providing a pump assembly as described above and hereinafter and capturing the droplets using the shield. The domed continuous surface is then the only portion of the dispenser that needs to be cleaned to remove such droplets.

The disclosure also relates to a dispenser comprising or configured to receive such a disposable fluid dispensing package. The dispenser may be manually activated or sensor-activated to exert an axial force on the pump assembly between the upper sleeve and the lower sleeve to cause axial compression of the pump and a reduction in volume of the pump chamber.

In an embodiment, the dispenser may comprise a housing and an actuator, wherein the housing and/or the actuator extends downwards in use at least as far as the lowermost rim of the shield and/or no portion of the actuator or housing is within a line of sight of the dispersion location. In other words, portions of the dispenser will be hidden by the shield from droplets or spray emanating from the nozzle. The housing or actuator may then cover the shield and the rest of the pump assembly from view.

The features and advantages of the present disclosure will be appreciated upon reference to the following drawings of a number of exemplary embodiments, in which:.

The disclosure will be described with reference to a working position wherein the terms upper sleeve and lower sleeve are used in the context of their relative locations when in use. The lower sleeve is the sleeve at a furthest distance from the fluid container when attached to the fluid container. The lower sleeve therefore is a sliding sleeve and the upper sleeve is a stationary sleeve, relative to the dispenser when installed.

<FIG> shows a perspective view of a dispensing system <NUM> in which the presently disclosed pump assembly as claimed in the appended claims may be installed. The dispensing system <NUM> includes a reusable dispenser <NUM> of the type used in washrooms and the like available under the name Tork™ from Essity Hygiene and Health. The dispenser <NUM> is described in greater detail in <CIT>. It will be understood that this embodiment is merely exemplary and illustrative, and that the current disclosure may also be implemented in other dispensing systems.

The dispenser <NUM> includes a rear shell <NUM> and a front shell <NUM> that engage together to form a closed housing <NUM> that can be secured using a lock <NUM>. The housing <NUM> is affixed to a wall or other surface by a bracket portion <NUM>. At a lower side of the housing <NUM> is an actuator <NUM>, by which the dispensing system <NUM> may be manually operated to dispense a dose of cleaning or sanitizing fluid or the like. The operation, as will be further described below, is described in the context of a manual actuator but the disclosure is equally applicable to automatic actuation e.g. using a motor and sensor.

<FIG> shows in perspective view the dispenser <NUM> with the housing <NUM> in the open configuration and with a disposable container <NUM> and pump assembly <NUM> contained therein. The container <NUM> is a <NUM> collapsible container of the type described in <CIT> and also in <CIT>. The container <NUM> is of generally cylindrical form and is made of polyethylene. The skilled person will understand that other volumes, shapes and materials are equally applicable and that the container <NUM> may be adapted according to the shape of the dispenser <NUM> and according to the fluid to be dispensed.

The pump assembly <NUM> has an outer configuration that corresponds substantially to that described in <CIT>. This allows the pump assembly <NUM> to be used interchangeably with existing dispensers <NUM>. Nevertheless, the interior configuration of the pump assembly <NUM> may be distinct from both the pump of <CIT> and that of <CIT>.

<FIG> shows the disposable container <NUM> and pump assembly <NUM> in side view. As can be seen, the container <NUM> includes two portions. A hard, rear portion <NUM> and a soft, front portion <NUM>. Both portions <NUM>, <NUM> are made of the same material but having different thicknesses. As the container <NUM> empties, the front portion <NUM> collapses into the rear portion as liquid is dispensed by the pump assembly <NUM>. This construction avoids the problem with a build-up of vacuum within the container <NUM>. The skilled person will understand that although this is an example for the form of the container, other types of reservoir may also be used in the context of the present disclosure, including but not limited to bags, pouches, cylinders and the like, both closed and opened to the atmosphere. The container may be filled with soap, detergent, disinfectant, hand sanitizer, alcohol-based sanitizer, skincare formulation, lotion, moisturizer or any other appropriate fluid and even medicaments. In most cases, the fluid will be aqueous, although the skilled person will understand that other substances may be used where appropriate, including oils, solvents, alcohols and the like. Furthermore, although reference will be made in the following to liquids, the dispenser <NUM> may also dispense fluids such as gels, including dispersions, suspensions or particulates.

At the lower side of the container <NUM>, there is provided a rigid neck <NUM> provided with a connecting flange <NUM>. The connecting flange <NUM> engages with an upper sleeve <NUM> of the pump assembly <NUM> in a snap connection. The pump assembly <NUM> also includes a lower sleeve <NUM>, which terminates at lower end <NUM>. The lower sleeve <NUM> carries an actuating flange <NUM> and the upper sleeve has an upper end with a locating flange <NUM>. Both the sleeves <NUM>, <NUM> may be injection moulded of HDPE although the skilled person will be well aware that other relatively rigid, mouldable materials may be used. In use, as will be described in further detail below, the lower sleeve <NUM> is displaceable by a distance D with respect to the upper sleeve <NUM> in order to perform a single pumping action.

<FIG> show partial cross-sectional views through the dispenser <NUM> of <FIG>, illustrating the pump assembly <NUM> in operation. According to <FIG>, the locating flange <NUM> is engaged by a locating groove <NUM> on the rear shell <NUM>. The actuator <NUM> is pivoted at pivot <NUM> to the front shell <NUM> and includes an engagement portion <NUM> that engages beneath the actuating flange <NUM>. The pump assembly <NUM> including the lower sleeve <NUM> is out of the line of sight of an operator by being concealed by the actuator <NUM>.

<FIG> shows the position of the pump assembly <NUM> once a user has exerted a force P on actuator <NUM>. In this view, the actuator <NUM> has rotated anticlockwise about the pivot <NUM>, causing the engagement portion <NUM> to act against the actuating flange <NUM> with a force F, causing it to move upwards. Thus far, the dispensing system <NUM> and its operation is essentially the same as that of the existing system known from <CIT>.

<FIG> shows the pump assembly <NUM> in exploded perspective view illustrating the upper sleeve <NUM>, the lower sleeve <NUM>, spring <NUM> and pump body <NUM>, all axially aligned along axis A. The pump assembly is thus formed from just four components. The spring <NUM> is provided with integrally formed inlet valve <NUM> and outlet valve <NUM>. The pump body <NUM> has an inlet end <NUM>, an outlet end <NUM>, a pump chamber <NUM> and an outlet nozzle <NUM>. The spring <NUM> and pump body <NUM> are formed of plastomer material and are generally as described in <CIT>.

The upper sleeve <NUM> is provided on its outer surface with three axially extending guides <NUM>. The lower sleeve <NUM> is provided with three axially extending L-shaped slots <NUM> through its outer surface. The lower sleeve <NUM> is slightly larger in diameter than the upper sleeve <NUM> and encircles it. The axial guides <NUM> on the outer surface of the upper sleeve <NUM> are arranged to engage within respective slots <NUM> in the lower sleeve. The L-shape provides a locking mechanism whereby rotating the lower sleeve <NUM> causes the guide <NUM> to move into the horizontal arm of the L-shaped slot, thereby preventing axial movement of the lower sleeve <NUM> with respect to the upper sleeve <NUM>. This prevents activation of the pump assembly <NUM> when the lower sleeve <NUM> is in this locked position, maintaining the pump body <NUM> in an uncompressed state e.g. during shipment and storage, prior to use. The guides <NUM> also prevent the lower sleeve <NUM> from being removed from its position around the upper sleeve <NUM> whereby the pump body <NUM> is retained within the sleeves <NUM>, <NUM>.

The pump assembly <NUM> can be assembled by moving all the components shown in <FIG> together by encompassing the spring <NUM> within the pump <NUM>, and both between the upper sleeve <NUM> which sleeve then slides into lower sleeve <NUM> and is retained by engaging axial guides <NUM> within the slots <NUM> in a snap-on connection. Once connected the sleeves <NUM>, <NUM> cannot easily be separated. The consequent pump assembly <NUM> can then be attached to a fluid container or a dispenser housing at the socket <NUM>, details of the socket are not described in the present disclosure but may be chosen according to the housing or container with which the pump assembly <NUM> may be applied.

<FIG> shows a cutaway view through the lower sleeve <NUM> cut along line VI-VI of <FIG>. The actuating flange <NUM> extends outwards from the lower sleeve body at the upper part. The L-shaped slots <NUM> are clearly shown.

In this view, it can be seen that the lower end <NUM> of the outer sleeve <NUM> terminates at a lowermost rim <NUM>. The rim <NUM> is annular and continuous and marks the beginning of a shield <NUM> that extends upwards and inwards to terminate at an orifice <NUM> having a lip <NUM>. The shield <NUM> between the rim <NUM> and the orifice <NUM> forms a domed continuous surface <NUM> of generally paraboloid shape.

<FIG> shows a cross section through the pump assembly <NUM> of <FIG> in its assembled state.

The pump <NUM> is located within the upper sleeve <NUM>. The lower sleeve <NUM> encircles the upper sleeve <NUM>. The actuating flange <NUM> extends outwardly and can abut the locating flange <NUM> when the pump chamber <NUM> is maximally compressed. The outlet end <NUM> of the pump <NUM> has a first diameter portion <NUM>, which forms a shoulder <NUM> extending inwards to the nozzle <NUM>, which has a smaller diameter than the first diameter portion <NUM>. The nozzle <NUM> extends downwards from the shoulder <NUM>.

As can be seen, the nozzle <NUM> protrudes through the orifice <NUM> of the shield <NUM> and extends downwards to end at a dispersion location <NUM>. This is the point at which a fluid, in use, will exit the nozzle <NUM> and no longer be thereby constrained. It is located at a distance L from the orifice <NUM>. The orifice <NUM> is larger than the nozzle <NUM> but smaller than the first diameter portion <NUM> so that the shoulder <NUM> can support stably against the lip <NUM>.

As can also be seen in this view, the nozzle <NUM> is recessed within the shield <NUM> and set back from the lowermost rim <NUM>. The position of the dispersion location <NUM> is such that a line drawn from a centre of the dispersion location <NUM> to the rim <NUM> forms an angle S with the axis of the nozzle. This is referred to here as the spray angle. In the illustrated embodiment, the length of the nozzle <NUM> is approximately <NUM> and its internal diameter at the dispersion location is around <NUM>. The distance L is around <NUM>, the shield has a diameter at the rim of around <NUM> and a depth to the orifice of around <NUM>. The spray angle S as defined above is around <NUM> degrees, although due to the diameter of the nozzle outlet, spray may be encountered up to around <NUM> degrees.

Operation of the pump assembly <NUM> and the dispensing system <NUM>, will now be explained with reference to the figures, in particular, <FIG> and <FIG>.

As noted above, <FIG> show how engagement of actuator <NUM> by a user causes the engagement portion <NUM> to act against the actuating flange <NUM> exerting a force F.

The force F causes the actuating flange <NUM> to lift and the lower sleeve <NUM> to move upwards with respect to the upper sleeve <NUM>. This force is transmitted from the lower sleeve <NUM>, via the lowermost rim <NUM> and the shield <NUM> to the orifice <NUM>. The lip <NUM> engages against the shoulder <NUM>, causing the outlet end <NUM> to move upwards together with the lower sleeve <NUM>. The inlet end <NUM> of the pump body <NUM> is prevented from moving upwards by its engagement with the socket <NUM> of the upper sleeve <NUM>.

The movement of the lower sleeve <NUM> with respect to the upper sleeve <NUM> causes an axial force to be applied to the pump body <NUM>. This force causes the pump chamber <NUM> to collapse and fluid to be ejected through the nozzle <NUM>. Reverse flow of fluid through the inlet end <NUM> is prevented by the inlet valve <NUM>.

When the pump assembly <NUM> is in the fully compressed state on completion of an actuation stroke, the lower sleeve <NUM> has moved upwards a distance D with respect to the initial position and the actuating flange <NUM> has entered into abutment with the locating flange <NUM>. In this position, pump chamber <NUM> and spring <NUM> have collapsed to a maximum extent.

It will be noted that although reference is given to fully compressed and collapsed conditions, this need not be the case and operation of the pump assembly <NUM> may take place over just a portion of the full range of movement of the respective components. The resilient nature of the plastomer pump chamber <NUM> and the spring <NUM> cause these elements to return towards their initial position by exerting a net restoring force to move the outer sleeve <NUM> back downwards to its initial extended position.

The force F required to collapse the pump chamber <NUM> is relatively high, being in practice more than <NUM> N. It is also not constant, due to the manner in which the pump chamber collapses. During the life cycle of a pump assembly, this fluctuating force must be repeated many times. As all of the force is to be transmitted through the shield <NUM> to the shoulder <NUM> of the pump <NUM>, it is important that the structure is adequate to withstand it without damage. Nevertheless, excess materials are undesirable, since the pump assembly <NUM> is intended to be single use and must therefore be as economical as possible. The domed continuous surface <NUM> of the shield <NUM> ensures the most efficient use of materials for this structure. In the illustrated embodiment, the thickness of the shield is just <NUM> and is substantially uniform, making it better suited to injection moulding. It is also substantially the same thickness of the lower shield and is otherwise unsupported except at its connection at the lowermost rim <NUM>.

During operation of the dispensing system <NUM>, fluid is ejected through the nozzle <NUM> over the full area of the dispersion location <NUM>. Depending on the nature of the fluid being dispensed, it may exit as a narrow-focused beam or jet, having a width similar to the internal diameter of the nozzle <NUM>. It is however the case that certain fluids have a tendency to spread out sideways and do not form a narrow beam or jet. Additionally, any caking of the fluid around the edges of the nozzle <NUM> may cause deflection of parts of the fluid in a lateral direction. In a worst case, droplets and spray can be deflected by at least <NUM> degrees and exit in a direction perpendicular to the axis A of the nozzle <NUM>.

As a result of the shield <NUM> extending forwards of the dispersion location <NUM>, any droplets that are emitted sideways will be caught on the domed continuous surface <NUM>. Only fluid and droplets that depart from the nozzle <NUM> within the spray angle S will exit the dispenser <NUM>. Importantly, it should be noted that in <FIG>, the lower sleeve <NUM> has moved upwards with respect to the actuator <NUM> and the dispenser housing <NUM>. In the absence of the shield <NUM>, stray droplets exiting in this position at the end of the stroke D would have a tendency to collect on adjacent surfaces, especially those of the rear shell <NUM> and the actuator <NUM>. By ensuring that these surfaces are not in a line of sight with any portion of the dispersion location i.e. well outside of the spray angle S, a build-up of undesirable droplets and spray can be avoided. It is noted that in the view according to <FIG>, it may appear that part of the actuator <NUM> passes beneath the nozzle <NUM> and shield <NUM> but the skilled person familiar with the referenced dispensers will be aware that the actuator <NUM> is provide with a cut-out portion at this location, allowing free passage of the dispensed fluid.

Claim 1:
A pump assembly (<NUM>) for dispensing a fluid from a fluid container, the pump assembly comprising an upper sleeve (<NUM>) and a lower sleeve (<NUM>), slidingly engaged together and a pump (<NUM>) having an inlet end (<NUM>), an outlet end (<NUM>) and a pump chamber (<NUM>), the pump being retained within the sleeves with the inlet end located at an upper end of the upper sleeve and the outlet end located at a lower end of the lower sleeve, whereby movement of the lower sleeve towards the upper sleeve from an extended position to a compressed position causes the pump chamber to reduce in volume,
wherein:
- the outlet end of the pump has a shoulder (<NUM>) between a first diameter portion and an outlet nozzle (<NUM>), the outlet nozzle extending downwardly from the shoulder and having a second diameter smaller than the first diameter portion;
- the lower end of the lower sleeve comprises a shield (<NUM>) for narrowing a spray angle of fluid exiting the outlet end of the pump, the shield extending from a lowermost rim (<NUM>) upwards and inwards to terminate at an orifice (<NUM>), the orifice being larger than the second diameter but smaller than the first diameter portion and the shield forming a domed continuous surface (<NUM>) that does not have any openings through which liquid or droplets might penetrate,
whereby the shoulder supports against a lip (<NUM>) of the orifice and the outlet nozzle extends through the orifice to terminate at a dispersion location (<NUM>) within the shield at a distance L from the orifice, and
wherein the domed continuous surface has a height of between <NUM> and <NUM> between the rim and the orifice.