The invention relates to a pump for dispensing a fluid product, comprising: a liquid chamber, for containing a liquid product; a liquid inlet valve, for admitting a body of liquid product into the liquid chamber; a liquid outlet valve, for regulating passage of liquid product from the liquid chamber to a dispensing head; and compression means, for applying a compressional force to the body of liquid product, thus forcing liquid product from the liquid chamber through the liquid outlet valve, additionally comprising: an air chamber, for containing air; an air inlet valve, for admitting air into the air chamber; an air outlet device, for conducting air from the air chamber to the dispensing head; and pressurizing means for reducing the volume of the air chamber, thus forcing air from the air chamber through the air outlet device, wherein the liquid inlet valve is elastically biased in a closed position.

In use, such a pump is conventionally connected to a reservoir, for containing a supply of the liquid product, which is admitted to the pump through the liquid inlet valve. In some applications, the pump will be located above the reservoir, with the liquid outlet valve above the liquid inlet valve (hereinafter referred to as a "standing configuration"); in other applications, however, the pump will be located below the reservoir, with the liquid outlet valve below the liquid inlet valve (hereinafter referred to as a "hanging configuration") .

Other configurations are, of course, also possible, e.g. with the pump located at a side of the reservoir.

For purposes of clarity and consistency, the following terms as used throughout this text and the appended claims should be interpreted as follows:

The term "fluid" should be interpreted as encompassing a liquid, a suspension of a granulated solid in a liquid, a gel, a foam, and a spray, for example.

The term "product" should be interpreted as encompassing soap (including shower gel) , shampoo, disinfectant (including alcohols), detergent, moisturizer, hair conditioner, and exfoliating scrub, for example, including mixtures of these substances .

The term "compression means" should be interpreted as encompassing a piston, bellows, balloon, and/or membrane, for example. The same applies to the term "pressurizing means".

The "liquid product" may be dispensed directly through the pump, or may first be mixed with another substance, such as air or another gas, another liquid, or a granulated solid, for example.

The term "reservoir" refers to any suitable type of container, whether rigid or flexible, such as a bottle, flask, or bag, for example.

A pump as described in the opening paragraph, when combined with a liquid reservoir as referred to in the second paragraph, forms a fluid product dispenser.

WO 03/089152 describes dispensers which combine a liquid pump and an air pump mounted at, or adapted to be mounted at, the neck of a container which contains foamable liquid. The liquid pump has a liquid pump chamber defined between a liquid cylinder and a liquid piston, and the air pump has an air pump chamber defined between an air cylinder and an air piston. Appropriate flow valves are provided to assure the operation of

the respective pumps. The liquid chamber usually has a liquid inlet valve. Either or both of an air outlet valve and a liquid outlet valve may be provided for the air discharge passage and the liquid discharge passage, respectively. In a proposal, the inlet valve is resiliently urged to a closed position, so that in the rest condition of the pump it prevents liquid from flowing from the container into the liquid chamber. This may be achieved by an upwardly-sprung valve body, or more preferably by a resilient valve member. Such dispensers are, for example, employed in washrooms, toilets, kitchens, hospitals, surgeries, hair/beauty salons, workshops and factories. In many cases, such dispensers are fitted in a holder that is mounted to a wall, often in the vicinity of a basin, bath, shower or toilet bowl; alternatively, such dispensers may be free-standing, and may be placed on a shelf, worktop or wash hand basin, or a trolley. In use, the pump is typically operated by hand, arm or elbow so as to dispense a quantity of fluid product. In general, this fluid product will be dispensed into the operator's hand, or onto a carrier such as a tissue or cloth, after which the fluid product is rubbed onto the skin or hair, or is applied from said carrier onto a surface to be sanitized, such as a toilet seat.

Generally, many of the environments referred to in the previous paragraph will have tiled floors and walls, at least in the vicinity of the sanitary facilities where the fluid product dispenser is often employed. The unintentional leakage of fluid or liquid product onto such tiled floors can lead to a slippery surface, with an attendant risk of injury to persons using those environments. In addition, chemicals present in the fluid or liquid product can adversely affect the finish on certain types of stone, e.g. by causing unwanted chemical reactions in limestone and marble, leading to unsightly blemishes on the stone in question. Moreover, apart from the damage that can be

caused by such leakage, it is also unsightly, costs time and effort to clean up, and wastes money in terms of lost product. These issues are of particular relevance in the case of dispensers used in a hanging configuration as referred to above. In addition, hygiene is important in many of the applications where such a fluid product dispenser is applied. Particularly in kitchens and surgeries, but also in toilets and hair/beauty salons, the dispenser's presence is intended to improve cleanliness and reduce the risk of infection. It is therefore important that the dispenser does not itself become a source of contamination. Often, the liquid product contained in the reservoir is sterilized, so that it is substantially free from (certain) pathogens. However, once that product comes into contact with air, it can become infected, e.g. by airborne bacteria, viruses and fungus spores. It is therefore important to ensure that product that has been exposed to the air, e.g. product residue remaining in the dispensing head after a previous actuation of the pump, is kept out of contact with the main body of liquid product in the reservoir. It is an object of the invention to address these problems. More specifically, it is an object of the invention to provide a pump, for use in a fluid product dispenser, which has reduced fluid/liquid leakage issues. Moreover, it is an object of the invention that such a dispenser should maintain a satisfactory level of sterility of the liquid product in its reservoir.

These and other objects are achieved in a pump as specified in the opening paragraph, characterised in that the liquid inlet valve is a duckbill valve. A pump according to the invention has several advantages. For example, if the pump is employed in a hanging configuration, below a reservoir, and the liquid outlet valve should fail for some reason (e.g. break, jam or wear), only the

liquid product contained in the liquid chamber can leak out of the pump - since the reservoir is sealed off from the liquid chamber by the fact that the liquid inlet valve is elastically biased closed. Because the liquid chamber generally has a drastically smaller volume than that of the reservoir (e.g. 0.4 ml vs. 800 ml in the case of a typical foam soap dispenser marketed by the applicant/assignee) , the quantity of liquid that can leak onto the floor in such cases is only a fraction of a percent of what it would otherwise be. This therefore significantly reduces the risk of injury due to slipping, the chemical erosion of stone surfaces, and the waste of liquid product .

Another advantage of the pump according to the invention is that, since the liquid inlet valve is elastically biased closed, contaminated product residue present in the dispensing head cannot make its way into a reservoir at the other side of the liquid inlet valve, and therefore cannot taint the contents of the reservoir.

A duckbill valve assumes the form of a tapering sleeve, with a relatively wide entry orifice and a relatively narrow exit constriction. The sleeve is manufactured from resilient material, such as rubber, which, due to its intrinsic elasticity, causes the sleeve to close in upon itself at the narrow end, thus closing the constriction. Only when sufficient force Fi is applied, will the biasing elastic forces concerned be overcome, causing the sleeve walls to separate at the narrow end, thus opening the constriction and allowing flow through the sleeve. As soon as the opening force falls below Fi again, the sleeve will close once more. In this manner, the duckbill valve is thus pre-loaded shut. In practice, the duckbill valve is positioned so that the sleeve tapers inward in the direction of intended flow. In a pump according to the current invention, therefore, the tip of the sleeve (the exit constriction) would

point into the liquid chamber, whereas the base of the sleeve (the entry orifice) would face toward the liquid reservoir dock. The valve can then be opened by creating an appropriate pressure differential across the valve, e.g. a negative pressure in the liquid chamber (or a positive pressure in the reservoir) ; the required negative pressure can be created during the pump's relaxation stroke (after its compression stroke) , whereby liquid product is sucked from the reservoir into the liquid chamber as the compression means relax (e.g. as a piston withdraws outward, or as a bellows or balloon expands) .

A further effect of the use of a liquid inlet valve that is elastically biased in a closed position, is that the ratio of the quantity of displaced air to the quantity of displaced fluid is determined more precisely. The volume of the body of liquid forced out with each stroke is more consistently the same .

The pump according to the invention can be any type of pump suitable under the circumstances. In a type of pump according to the invention, the fluid product is foam. An embodiment of such a pump additionally comprises: a mixing element, located in the dispensing head, for mixing liquid product and air emanating from the respective liquid and air chambers.

The mixing element may, for example, be a mixing chamber and/or a porous member, such as a gauze, sieve or mesh, for example. The air outlet device may be a valve, a narrow duct, a swan neck, or a labyrinth passage, for example. The term "air" should be broadly interpreted as encompassing other gases, such as N ₂ , for example. A foam pump of this type is described, for example, in US 5,271,530 (Daiwa Can Company) and US 2004/0149777 (Taplast) .

In yet another type of pump according to the invention, the fluid product is a spray. Such a pump comprises a

constriction positioned in such a way that liquid emanating from the liquid chamber is caused to flow through the constriction. Such pumps are well known in the art.

In many applications, a pump according to the invention will be used in a holder comprising: a housing, removably accommodating at least part of at least one of: a reservoir, for containing a liquid product, and; the pump according to the invention, connectable to the reservoir, for dispensing a fluid product using the liquid product as an input, further comprising at least one of :

(i) an actuating organ movably connected to the housing and serving to cooperate with said pump, whereby the pump can be actuated by manually moving the actuating organ;

(ii) a detector, for detecting that a member onto which fluid is to be dispensed has been offered to a dispensing head of the pump, and; an electric actuator, for actuating the pump on the basis of a signal output from the detector.

The actuating organ referred to may comprise a lever, button, hinged part, or wheel, for example; if so desired, it may be an integral part of the pump, such as in the case of a cap on a moving part of the pump. The employed detector may, for example, be based on heat detection, movement detection, the interruption of a light beam, a change in scattered light intensity (albedo change) , etc. indicating that a member such as a hand, cloth or tissue is being offered to the dispensing head, i.e. appropriately positioned to receive fluid product dispensed from that head. In many or most cases, such a holder will comprise means (such as screw holes, magnets, etc.) for mounting the housing to a surface, such as a wall.

It should be noted that, to safeguard against unwanted leakage of fluid product, the liquid outlet valve may also be embodied as a duckbill valve or umbrella valve that is elastically biased in a closed position. The invention will now be elucidated in more detail on the basis of exemplary embodiments and the accompanying schematic drawings, in which:

Figure 1 shows a cross-section of a pump for dispensing a fluid product, according to the prior art. Figure 2 shows a cross-section of a pump for dispensing a fluid product.

Figure 3 shows a cross-section of a pump for dispensing a fluid product .

Figure 4 renders a perspective view of a pump incorporated in a holder.

Figure 5 renders a longitudinal cross-sectional view of the subject of Figure 4, taken along the line AA' .

In the Figures, corresponding features are indicated by corresponding reference symbols.

Embodiment 1

Figure 1 renders a cross-sectional view of a pump 100 for dispensing a fluid product, according to the prior art. In this particular case, the fluid product is a foam, produced by mixing a liquid product with air. The pump 100 comprises: a liquid chamber 102 for containing a liquid product; a liquid inlet valve 104 for admitting a body of liquid product into the liquid chamber 102; a liquid outlet valve 106 for regulating passage of liquid product from the liquid chamber 102 to a dispensing head 107;

compression means 108, for applying a compressional force to the body of liquid product, thus forcing liquid product from the liquid chamber 102 through the liquid outlet valve 106.

Also present are: an air chamber 110, for containing air; an air inlet valve 112, for admitting air into the air chamber 110; an air outlet device 114, for conducting air from the air chamber 110 to the dispensing head 107; pressurizing means 116, for reducing the volume of the air chamber 110, thus forcing air from the air chamber 110 through the air outlet device 114; a mixing element 118, located in the dispensing head 107, for mixing liquid product and air emanating from the respective liquid chamber 102 and air chamber 110.

Also depicted is a collar 119, by means of which the pump 100 can be attached to a reservoir 20 (not depicted in Figure 1) . Figure 5 shows a pump 100 coupled to a reservoir 20 in a hanging configuration, for example. In the illustrated embodiment, the following design choices have been made:

The compression means 108 are embodied as a piston, with a piston shaft 111 and an attached piston head 113, which can be moved telescopically in and out of a piston tube 103. The piston shaft 111 is hollow, and has a central passage that forms part of the liquid chamber 102. Moving the dispensing head 107 toward the collar 119 causes the piston 108 to start a compression stroke, applying pressure to a body of liquid product present in the liquid chamber 102, and thus forcing liquid product from the liquid chamber 102 through the liquid outlet valve 106. On the other hand, moving the dispensing head 107 away from the collar 119 causes the piston 108 to start a relaxation stroke, causing negative pressure to build up in the

(empty) liquid chamber 102. If desired, elastic biasing means (such as a spring) can be employed to ensure that the piston 108 starts its relaxation stroke of its own accord once it is released from its compression stroke. The pressurizing means 116 are embodied as a bellows, within which is located the air chamber 110. Moving the dispensing head 107 toward the collar 119 compresses the bellows 116, reducing the volume of the air chamber 110 and thus forcing air from the air chamber 110 through the air outlet device 114. On the other hand, moving the dispensing head 107 away from the collar 119 causes the bellows 110 to relax, whereby air will be sucked into the bellows 110 through the air inlet valve 112. If the bellows 110 is made of resilient material, such as flexible plastic or rubber, it will be self-relaxing. The air outlet device is embodied as a labyrinth of narrow passages.

The skilled artisan will appreciate that these are free design choices, and that many other worthy alternatives are available, as alluded to earlier in this text. In the depicted pump 100, the liquid inlet valve 104 is not elastically biased, and is here embodied as a ball bearing 104w that is free to move between two flanges 104x and 104y. When used in hanging configuration (so that the pump 100 is upside down as compared to its depiction in Figure 1) , the flange 104x will form a valve seat against which the ball 104w can be pressed in a sealing manner; on the other hand, the flange 104y will act as a retainer, serving to prevent the ball 104w from falling (under the influence of gravity) into the liquid chamber 102, but being shaped such that liquid can nevertheless flow in the space between the ball 104w and the flange 104y, even when the ball 104w rests against the flange 104y. In use, such a liquid inlet valve 104 will normally be open, i.e. the ball 104w will rest against the flange 104y

(under the influence of gravity) . Only when sufficient pressure is built up in the liquid within the liquid chamber 102 (by movement of the piston 108 toward the liquid inlet valve 104) will the ball 104w be pushed away from flange 104y and toward valve seat 104x, thus closing the liquid inlet valve 104.

Because the liquid inlet valve 104 in the previous paragraph is default open in hanging configuration, it will allow a continuous leak of liquid from the reservoir 20 through the dispensing head 107 in the event of a failure of the liquid outlet valve 106.

Embodiment 2

Figure 2 shows a cross-section of a pump 100 for dispensing a fluid product, according to an embodiment of the current invention. The pump 100 in Figure 2 is identical to that in Figure 1, except as regards the liquid inlet valve 104.

According to the invention, the liquid inlet valve 104 is elastically biased in a closed position. In this particular embodiment, the liquid inlet valve is embodied as a duckbill valve. The duckbill valve 104 has a wall 104c of resilient material, in the form of a tapered sleeve. This sleeve 104c has a narrow end 104a (the exit constriction) and a wide end 104b (the entry orifice), and is positioned such that, when viewed from a liquid inlet orifice 121 in flow communication with a supply of liquid product in a reservoir 20, the narrow end 104a is distal and the wide end 104b is proximal, i.e. the valve sleeve tapers inward away from the reservoir 20 (and the liquid inlet orifice 121) and toward the liquid chamber 102. In use, the valve 104 will be elastically biased closed, as depicted in Figure 2. During the compression stroke of the piston 108, the valve 104 will remain closed. However, during the relaxation stroke of the piston 108, a negative

pressure will arise in the liquid chamber 102, causing liquid product to be sucked through the valve 104 from the liquid inlet orifice 121; once the relaxation stroke has ended and the negative pressure in the liquid chamber 102 disappears again, the valve 104 will close once more.

Because the duckbill valve 104 is elastically biased closed, contaminated liquid product in the liquid chamber 102 and/or dispensing head 107 cannot migrate back into the reservoir 20. This means that a supply of sterilized liquid product in the reservoir 20 will not be contaminated by backflow through the valve 104.

If the pump according to the invention is used in a hanging configuration, as shown in Figure 5, for example, then the fact that the valve 104 is elastically biased closed will limit leakage of liquid product in the event of a failure of the liquid outlet valve 106. If liquid outlet valve 106 were to break, jam or wear, for example, only the liquid product contained in liquid chamber 102 would leak out through the valve 106; the much greater supply of liquid product in the reservoir 20 would be held back by the inventive liquid inlet valve 104, which is elastically biased closed by default.

Embodiment 3

Figure 3 shows a cross-section of a pump 100 for dispensing a fluid product. The pump 100 in Figure 3 is identical to that in Figure 2, except as regards the details of the liquid inlet valve 104.

In Figure 3, the liquid inlet valve 104 is elastically biased in a closed position. In this particular embodiment, the liquid inlet valve is embodied as a valve seat 104f and cooperating ball bearing 104g. A resilient member 104h, such as a

spiral spring, rests against a retainer 104i and thrusts ball bearing 104g against valve seat 104f with a force F ₀ .

In use, the valve 104 will be elastically biased closed, as depicted in Figure 3. During the compression stroke of the piston 108, the valve 104 will remain closed. However, during the relaxation stroke of the piston 108, a negative pressure will arise in the liquid chamber 102. If the inward force exerted on the ball bearing 104g as a result of this negative pressure exceeds the elastic biasing force F ₀ , then liquid product will be sucked through the valve 104 from the liquid inlet orifice 121; once the relaxation stroke has ended and the negative pressure in the liquid chamber 102 disappears again, the valve 104 will close once more.

Embodiment 4

Figure 4 shows a holder 12, which can be mounted to a wall of a washroom, for example. The holder 12 houses a reservoir 20, for containing a liquid product, and an attached pump 100 according to the invention; these items are only visible in Figure 5, and will be discussed later in more detail. An actuating organ 14 is movably connected to the holder 12, and can be actuated so as to operate said pump 100. Also shown are an inspection window 16, which allows the amount of liquid product in the reservoir 20 to be seen from outside. An aperture

18 allows insertion of a tool with the aid of which the holder can be unlocked and opened, allowing access to the reservoir 20 and pump 100 located within.

Figure 5 renders a cross-sectional view of the subject of Figure 4, taken along the line AA' . The reservoir 20 is now visible, and may be embodied to be rigid or flexible (e.g. collapsible) . It can be made of any suitable material, such as plastic or glass, and may take the form of a bottle, flask, or

bag, for example. The liquid product contained in the reservoir 20 may, for example, comprise soap, shower/bath gel, shampoo, disinfectant (including alcohols), detergent, moisturizer, hair conditioner, exfoliating scrub, or mixtures of these products. The above-mentioned document US 5,732,853 describes such a reservoir, and means by which it can be coupled to a pump.

As can be seen in Figure 5, the actuating organ 14 in this instance is hinged to the holder 12 via a hinge joint 26. This, together with the gap 28 below the actuating organ 14, means that the actuating organ 14 can be swung in and out of the holder 12. An arm 30 connects the actuating organ 14 to the pump 100 in such a manner that, when the actuating organ 14 is swung into the holder 12 about hinge point 26, arm 30 operates pump 100 so as to dispense a dose of fluid product through the nozzle 24. Elastic biasing means, such as spring 32, ensure that the actuating organ 14 is urged back into its swung-out position when released. In general, a user depresses the actuating organ 14 using his hand palm, lower arm or elbow, for example, and collects the fluid product dispensed from the nozzle 24 in his hand or on a carrier (such as a cloth or tissue) ; for convenience, the nozzle 24 will therefore generally face substantially downward or outward from the holder 12.

The pump 100 is removably mounted to a bracket 36 that protrudes from the back wall 34 of the holder 12. This back wall 34 can be provided with screw-holes, magnets, or other means for mounting it to a wall or other surface. Also protruding from the back wall 34 is a lug 38B, which grips a cooperating lug 38A; however, using a tool inserted through aperture 18, these two lugs 38A, 38B can be disengaged, allowing the housing 12 to be opened, e.g. so as to replace the reservoir 20 and/or pump 100 located inside.

The pump 100 may be any suitable type of pump for the application in question, such as a spray pump or foam pump, for

example, and may operate on the basis of a movable piston, bellows and/or membrane, for example. In operation, the pump 100 dispenses the liquid contained within the reservoir 20, first mixing it with air. In all cases, the pump 100 dispenses a fluid product from the nozzle 24.